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Home My WebLink AboutAPA1389I .. i -J ' r , [" I • I I I I susrrNA H'lDROELECTF-1iC PROJECT I ACRES INTE:~NAL REVIEW BOARD I f•AEETI NG # 4 I I I I .j I J ' I I I I REPO~T I SEPTE~IIBER 8, ~981 I I I ~repared Jy: I r- ' I I I hfJ~f~ .. I l1!~Lj I I I I I I I • ~---At t\SY.' \ POWER AUTHOR IT"!' ~ -·-------...... J '·· "'•,/• L__ I I I I I I I I I I I I I I I I I I I I ALASKA POWER AUTHORitY ~ SUSITNA HYDROELECTRIC PROJECT Internal Review Board Meeting No. 4 MINUTES OF MEETING held at the offices of Acres Consulting Services, Niagara Fa 11 s, Canada on September 8, 1981 TABLE OF CONTENTS Agenda/List of Attendees 1. General Remarks 2. Status of Studies 3. Status of Seismic Studies 4. Status of Geotechnical Field Work 5. Approach to Spillway Designs 6. Devi 1 Canyon Layout Studies 7. De vi 1 Canyon Ar::h Dam An a lyses 8. Approach to Watana Layout Studies 9. Watana Dam Design 10. Watana Dam Layout Studies 11. Watana Relict Channel Studies APPENDIX A -Supporting Documentation APPENDIX B -Review Board Report September 30, 1981 P5700.J.3 I I I I I I I I I I I I I I I I I 'I I ALASKA PO~lER AUTHORITY SUSITNA HYDR!)ELECTRIC PROJECT · INTERNAL REVIEW BOARD MEETING NO. 4, NIAGARA FALLS, CANADA SEPTEMBER 8, 1981 AGENDA 1 -0830 -General Remarks -Dr. D. MacDonald 2 -0845 -Status of Studies -J. D. Lawrence 3 -0915 -Status of Seismic Studies -V. Singh 4 -0945 -Status of Geotechnical Field Work -S. N. Thompson -1015 -Coffee and Discussion 5 -1030 -Approach to Spillway Designs -Dr. J. W. Hayden 6 -1115 -DevJ1 Canyon Layout Studie$ -R. K. Ibbotson 1200 -Lunch and Discussion 7 -1300 -Devil Canyon Arch Dam Analyses -R. K. Ibbotson 8 -1330 -Approach to Watana Layout Studies -J. D. Lawrence 9 -1345 -Watana Dam Design -D. W. Lamb 1500 -Coffee and Discussion 10 -1515 -Watana Dam Layout Studies -R. K. Ibbotson 11 -1630 -Watana Relict Channel Studies -V. Singh ATTENDEES Review Panel Dr. D. H. MacDonald Dr,. I. McCaig J. G. S. Thomson L. Wolofsky H. Eichenbaum I •• I I I I I I I I I I I I I I I I- I Presenters Observers J. D. Lawrence ~ J. W. Hayden., S .. N. Thompson . V. Singh R. Ibbotson D. W. Lamb A,. Burgess (afternoon only) G. Krishnan D. Meilhede R. Miller (afternoon only) L. Duncan R. Shery D. Shandalov (10:30 -13:30) M. Dumont T. Gwozdek (afternoon only)· D. t.Jillett M. Vanderbu_rgh I 'j""\ ' , A_l • . A.' " "" • I • .r\ ,, •• ( i ,\.f •. ~· r . I I I I I I I I -I I I I I I I I I I I 1. General Remarks (Dr •. D.H. MacDonald) In view of the restricted time available and the amount of material to be presented and -discussed, Dr. MacDonald suggested that only pertinent remarks be raised at the meeting. Separate meetings should be arranged later for detailed discussion of points of interest. 2. Status of Studies (J.D. Lawrence) General J.D. Lawrence reiterated the tight schedule of the Agenda, and requested close adherence to it, without wishing to prevent useful discussionb He also requested that the Review Board members summarize and confirm in writing their major concerns and points raised during the meeting. Minutes· M. F .. Dumont waul d be recording the Minutes of the Meeting; J.D. La\"trence requested all presenter·s should provide him with copies of ail pertinent documentation, slides and figures. 1981 Progress (i) Hydrology: -Field recording of flows and sedimentation studies -Flood analysis continues -Energy studies continue based on reservoir simulation progl'·am (ii) Seismic: (iii) -13 features have been identified as significant for study. Geo- logic mapping continuing. Geotechnical: Intensive program of seismic refraction studies and auger boring continues at both sites. Field studies continue on foundation conditions and material from ·~the borrow areas. -In addition, further study of the relict channel is anticipated. ( i v) Design: -The development of design· for the dam and power facilities at each site continues. I I I I I I I I I I I I I I I • ~ I I (v) Environment: -Studies continue on temperature stratification and water quality in the reservoirs with particular emphasis for design, and on fish and game impacts~ -Access roads -Transmission line route (vi) Costs/Schedule: -An upper limit cost estimate was prepared earlier this year. -Preliminary cost estimates for the preferred developments will be .prepared in October/November for vetting by an external consultant (to be elected by APA). (vii) Licensing: -On schedule (viii) Finance/Risk: -The State has passed legislation which should ensure the financial viability of the project. The implications are being 1 ook ed i nt. 0. Deadlines (i) Development Selection Report: -The draft has now been reviewed by Client, Federal and State Agencies and is being revised for general issue. (ii} w.c.c. Fieldwork: -On schedule (iii) R&M Fieldwork: -On schedule (iv) APA External Board: -Meeting scheduled for October 6-8, in Buffalo, to consider recommended layouts at Hatana and Devil Canyon. (Economics and environmental aspects are not scheduled for discussion.) (v) Cost Estimates: -Preliminary cos~ estimates will be provided as follows: Devil Canyon: End of October·I981 Watana: End of November 1981 I I I I I I I I I I I I I I I I I 'I I • • . .. . ~J . '. .. • '. • . . . • . • ., . !1 . I • I. .. • • . . ·-.· . ·~·: .. -~ r .. · • . :.. . •. .;_.~ .. ~ ·. ;_. . : .. < '. • .~:· .. :.··. . ... ·. · . .' ·-~-.' - : ·.: -. . . · .. '· . . . . : . . . . . : . . : ~.... . : . . :. : .·. . . . . . . : ··"· , (vi) Geotechnical Report: -1980 Program -September 1981 -1981 Program -February 1982 (vii) Feasibility Report: -First draft due February 1982 -Final draft must be available by March 15, 1982 for general ci rcu l at ion. (Certain environment a 1 aspects wi 11, however, be studied further between March 1982 and June 1982; APA are aware of this) .. (viii) FERC license: -Submit to APA by May 1982, for both Watana and Devil Canyon, (as a result of a previous Review ~oard recommendation). Previous Points of Discussion (for reference) ( . ' 1 I ( 1 i) (iii) Acres Internal Review Board Meeting No. 3 (February 1981): -Watana Dam slopes of 2.5H:lV U/S, 2.0H:1V DIS reviewed -Fingerbuster (downstream shear zone) to be included in WCC studies -Nitrogen supersaturation problem highlighted (spillways) -Low level outlet design concepts discussed -Multi-level intake design requirements -Earthfill dam at Devil Canyon considered -Watana dam schedule tight for the volume involved -license application should include Devil Canyon Acres External Review Board Meeting (Februaryj: ... Seismic activity along Talkeetna Thrust, KD 37 (line along river), Susitna feature, Benioff Zone, and nfloating" eq -Nature of the andesite/ diorite cant act -Relict channe 1 -Depth of a 11 uvi urn at the upstream cofferdam -Devi 1 Canyon: Concern about shear zones Design of underground powerhouse, sul'·face powerhouse, dam section, .Watana arch alternative. APA Review Board Meeting (June) -Fieldwork in the relict channel -Underground powerhouse exploration -Downstream erosion -Seismic1ty and nitrogen supersaturation problems highlighted -The Orovi 11 e dam s 1 ope was considered acceptable for upper 1 i mit cost estimate for Watana (2.75 H:lV) -Downstream water qua 1 i ty concerns emphasized I I I I I I I I I I I I I I I I I il I 3. Current Layouts These would be described in detail later by R.K. Ibbotson but major changes would be: De vi 1 Canyon: Watana: Orifice spillways changed to HB valves Dam slope upstream amended to 2.4 major structures on the right bank Status of Seismic Studies (V. Singh) Previous Work Thirteen features had been identified as requiring further study; 9 at Devil Canyon, 4 at Watana. Three features were accepted as having a major effect on the sites: -Denali Fault (8.5 M) -Castle Mountain Fault (7.5 M) -Benioff Zone (8.5 M) w.c.c. Findings from 1981 Studies -Watana: -Talkeetna Feature: Considered to be inactive. -Susitna Feature: No evidence of a fault. -KD37 (River Feature): No evidence of a fault. -Fins: A fault but size is insignificant. -Devil Canyon - 3 faults identified, but inactive. - 6 others may be faults, but also considered inactive. w.c.c. Co~clusions -Three major features identified are Denali, Benioff, and Castle ~1ountai n. - 11 Floating 11 earthquake, is related to the Benioff Zone, (5 to 5 .. 5 M). Report may propose probab i 1 i st i c approach to potentia 1 movements near structures. Panel Comments -On what basis was Talkeetna considered inactive? s. Thompson explained good evidence available to the South (50 million years), less good to the north (only 12,000 years). I I I I I I I I I I I I I I I • I I I I 4. 5. -The panel were concerned with a probabilistic approach to prediction of 1 ikely earthquake motions near structures. -It was notei· that fault inactivity was presumed on a basis of 1 ack of specific e r~dence of activity., StatU$ of Geotechnical Field Work (S. Thompson) Summary of 1981 Work (a) Watana: -BH 12 (powerhouse left bank) drilled. -BH 1 (powerhouse right bank) drilled. ~ BH 3 (powerhouse right bank) drilled. -Seismic refraction studies in the river upstream and .downstream to assess the depth of alluvium. -A summary of rock quality (RQD values) with depth was presented; the right bank pO\'Ierhouse v1ill be in good quality rock. (b) Devil Canyon: -Pond feature has been confirmed as a shear alignment (inactive) -BH 5, BH SA drilled in and near the river. - A feature in the river at the Devi 1 Canyon arch dam site has been identified from Acres drilling and confirmed by interpretation of Corps of Engineers cores as probably an inactive fault, thought to be small at this time. Not sufficient evidence to justify changing from arch dam design to rockfill at this time. Further investigations are in progress to obtain more data on this feature. (c) Layouts: -Watana: Avoid Fins structure with upstream diversion portal~ Approach to Spillway Designs (J. Hayden) Current Design Concepts -Philosophy: ( i) f .. ) \11 Diversion flow -1 in 50 years Nitrogen s_upersaturati on -accepted 1 in 100 years Design flood -1 in 10~000 years ( i i;) ( iv) Probable Maximum Flood I I I I I I I I I I I I I I I I I I I -Devi 1 Canyon: Values allow for routing through Watana,_which is assumed constructed. (a) Watana Diversion: 2 tunnels 35 feet diameter -Lo\>Jer tunnel_ pressi.!re, upper free flow vlhich can be converted to low level outlet. Both concrete lined, design velocity 50 ft/sec. -Upper tunne 1 waul d be c 1 eat~ of possi b 1 e upstream sedimentation -Emergency capacity of 10-30,000 cfs, capacity dependent on head, and energy dissipater for flood during construction. Service Spillway (tunnel and values): -6 H.B. valves designed to mitigate nitrogen supersaturation for any flood up to the 1 in 100 year occurrence. Also provides mid level release for drawing down top 200 feet of reservoir. Power Flow: - A 11 owed in fl cod routing up to 1 in 100 year floods Not for any higher flow. Auxiliary Spillway (headgates, chute and flip bucket): -Used for floods greater· than the 1 in 100 year occurrence, when nitrogen supersaturation is considered acceptable, up to the 1 in 10,000 year flood, with some surchanging of the reservoir (up to 7 feet). Emergency Spillway: -Fuse plug dam fails~ passing the PMF. (b) Devil Canyon -Diversion: One tunnel -Service Spillway: 5 HB valves in the face of the dam -AuxiTi ary Spi 11 way: Chute and st i 11 i ng basin on the right bank -Emergency: Fuse plug dam as at Watana Panel Comments -Precedents should be established for diversion tunnel velocity of 50 ft/s, HB operation requirements and spillway design concepts .. I I ·I· I I I I I I I I I I I I I I I I -Dam break analysis of cofferdam required in vie\~ of volume of water retained; possible costs of damage down·stream would affect optimization of tunne 1 diameter, and te.:d toward 1 arger tunne 1 with 1 ower coffer darn .. ~ All chutes will require aeration. -Possible to design a cofferd~m that can safely be overtopped. -Fuse plug dam must bE: stable up to a fixed level and collapse ~hereafter; a gated structure waul d be more expensive, but more re l i ab 1 e. -Stilling basin walls at Devil Canyon are subject to dynamic water 1 oadi ng. -HB valves would cause icing problems in winter; although normal spillway operation would be in summer, it could also occur at unscheduled times. Loss of 1 oad owing to major industria 1 action \vas cited as a precedent for forced spilling. 6. Dev i 1 Canyon Layout Studies (R. K,. Ibbotson) Options Considered (a) Powerhouse on right bank, 2 diversion tunnels on left bank, 4 orifices in the dam for auxiliary spillway discharging into a plunge pool at the dam toe, chute and flip service spillway on right bank. (b) As (a) but service spillway replaced with chute and flip on left bank. (c) As (a) but service spillway replaced by stilling basin on the right bank~ The preferred option was the stilling basin, to avoid extensive erosion downstream of the dam, and consequent high maintenance costs. Nitrogen Supersaturation Because of the nitrogen supersaturation problem, the orifice spillway has been changed to 5 H.B. valves as a service spillway; the stilling basin now will be used as the auxiliary spillway for floods in excess of the 1 in 100 year occurrence. Extension to Portage Creek Cost/benefit analysis for the tailrace extension to Portage Creek has been done, indicating CBR of about 1o Difficult tunnelling with little geotechnical data available. Panel Comments -Stilling basin walls are too thin if unsupported by rock. I I I I I I· I I I I. I I I I I I I I I -Need for precedent/experience report on HB valves particularly with regard to vibration and winter operation. Model studies will be required in design stage. (• -Recommended at· least lOD straight section before the valve to establish linear flow pattern~ (particularly at Watana). -To avoid supercooling the trashracks on the intake should not be exposed above W~L, -Switchyard position is on opposite bank to powerhouse .. -Tailrace shown is freeflow; one extra set of gates? 7. Devil Canyon Arch Dam Analyses (R .. K. Ibbotson) Previous \~ark -Static analysis was completed. Current Studies -Dynamic.analysis has now been completed plus minor geometry chan9es to achieve a more symmetrical distribution of stress. -Crest elevations are 10 feet lower than present thinking~ (1445 EL). -All work is done by Trial-load method. Results Static Cases: (i) Self weight+ normal hydrostatic {ii) s.w. + drawdown (1295) (iii} Full reservoir +temperature (iv) Drawdown + temperature Tensions stresses were as follows: (i) -27 psi {ii) -97 psi (iii) -393 psi Dynamic: 0.5g and 5% damping ratio: -2470 psi in arch These results were discussed with Merlin Copen who stated 10% damping ratio was applicable. Design earthquake was also reduced to 0.4g and the analysis repeated. Revised stresses (maximum tension); -1390 psi in arch I I .~ I I I I I I I I I I I I I I I I Allowing for redistribution of_tensile stresses by cracking, the maximum tensile stress is -322 psi in the arch. If the water dynamic load is reduced 60% for valley shape and constricted approach~ the maximum tensile stress is -251 psi. Pane 1 Comments • Consider possible finite element analysis check on desigD by ISMES (Italy) D. Shandalov stated F.E. analysis does not allow for stress r e 1 i ef by crack i n g. -Plastic non-recoverable deformation of abutments. This may be offset by grouting, which would tend to strengthen rock and give a more elastic response under load. 8. ~oach to Watana Layout Studies (J. D. Lawrence) It had been agreed that until the rockfill dam design had advanced sufficiently to warrant steeper dam slopes, conservative Oroville dam slopes would be adopted for layout studies on the other major structures, (2 .. 75:1 upstream, 2:1 downstream). These slopes were also used to prepare the upper limit cost estimate. Field data are now being used to firm up the design with a view to steepening the side slopes to ease the site congestion. 9. Watana Dcm Design (D. W. Lamb) Borrow Areas (~) Ti11 from borrow area D has hig: Jermeability (lo-5 em/sec) but is otherwise suitable for the cor~-On the wet side of optinum moisture content by 2-5%. Control on con:o. ction wi 11 be difficult. Estimates are to be adjusted to allow for haul distance, placing and compaction methods. Low P. I. on most s amp 1 es. Some evi de nee of no c 1 ay at depth. Borrow area His also available; longer haul distance. (b) Filter material (Area E) must be processed for use,~ probably from a dragline operation, in 2 bands: -Fine grained -~ Coarse Some of fine grained may be s~iJ:eb 1 e for the core. (c) Rockfill -This will be from quarry. (d) Minimal data on river alluvium. Core. and filter specs may need to be tightened up, which will affect costs. (e) Quantities -·An average of 2 to 5 times the volume requirements, which is on the low side. Fine filter materia 1 may be tight. I I I I I 1: I I I I I I I I I I I I I (f) Quarry is in the andesite (at least at the surface), which may not be suitable for concrete aggregates. Design Factor~ {a) (b) (c) (d) Core thickness will be about 50% of· the head of water acting. Core ·wfll be central and essentially symmetrical. Filters are a minimum of Hi ·feet thick. Crest width currently 50 feet for provision of a road& Present sl ooes fall ow Oro vi n ~ dam which sustained 5. 8M in 1975 without damage. Checks su9gest it is safe up to 8.25M. Design work currently assessing stability of upstream slope of 2.25. Fai 1 ure under earthquake 1 oadi ng was discussed, as de.scribed in Seed's Rankina Lecture,. together with design details which would avoid possible failure mechanisms, e.g., use of rounded gravels as upstream fill. - Grouting ~tiOuld be either from the surface or from a gallery under the dam. The gallery is believed to be useful for instrumentation!t access for remedial works, and to avoid schedule delays. Disadvantage is drainage and pumping necessary. (e) Core contact. This will be flared to 100 feet minimum at the abutments. Analysis (A. Burgess) (i) 2.25 slope dynamic analysis is being done at present by computer ·analysis, using assumed rockfill properties. Variation in material properties caused by current 1 ack of rea 1 i sti c test data for fill materials will be subject of sensitivity analysis. Static analysis and slope stability studies will be done later. c (ii) Finite element methods are being used to assess the dynamic stability under earthquake loading. Material properties under cyclic leading are available only for sand, these have been uprated to estima~ed gravel v-~lues. · Static analysis results shown (performed initially to determine stress levels in dam) represent arching across the core, with some cantilever action of the up~er coreo Dynamic stress analysis shows highest stresses in the upstream face of the core and the upstr·eam rockfill, using a simulated earthquake of record. This has to be repeated 1 ater with the WCC predicted earthquake record. The last ph as~ of design wi 11 be amending these dynamic results to a 11 O\\f for pore water pressure distribution. Panel Comments -Any problems with frost damage in the core ? Shou1 d be a 11 ov1ed for in the unit costs I, I I I I I I I I I I I I I I I I I I -Widths of filters and transitions are too smalL. -Several Chinese rockfill dam failures under earthquake have been analyzed and failure modes reconstructed; the published work (ICOLD, 1980) should be studied. -Assumed' lift height currently 3 feet for rockfill. This is very critical to schedule. 10. Watana o·am Layout Studies (R.K. Ibbotson) All 1 ayouts are governed by the requirement to set dam and .structures between the major shear features (Fins and Fingerbuster). ( i) Cascade spillway on 1 eft bank. This 1 ayout has been kept in as a means of resolving the nitrogen supersaturation problem. Trade off in rockfill for use in the main dam was allo\>led for. Rockbc1ting and other strengthening measures allowed for in cost estimate~& (ii) Preferred (least cost) layout has chute and flip on right bank; nitrogen supersaturation up to 1 in 100 year flood eliminated by use of HB valves as service spillway. The upstr~am dam slopeais shown at 1 in 2.4. 1 in 2.25 is at present being analyzed, which would give more flexibility with arrangements of structures and position of dam centerline. Panel Comments -Downstream tunnel portals are too close together for construction. -Precedent for use of HB valves as primary release devices? Need for a report on their use was reiterated. -Significance of upstream dam slope? Change from 2. 75 to 2.40 reduces cost by $10 million, with adjustment of dam center line. 11. Watana ~elict Channel Studies (V. Singh) -Since the channel ·may affect the feasibi 1 ity of the project, a cost has been assigned to cover investigation. and remedial work. -Seismic lines were extended to trace the extent of the channel. Cross sections have been drawn, based on present information. 45 million dollars has been allowed for a continuous cut-off (slurry trench) to avoid piping failure. Saddle dam slopes are flat to allow for earthquake settlement and maintain stability .. I I I I I I I I I I -• I. I I I •• I I I -Further study will be undertaken in Phase 2 {auger drilling, Becker dri 11 i ng) e Rock surface contours wi Tl be drawn based on 6 boreho 1 es and seismic refraction lines. Permeability measurements will be required in Phase 2; also adits may be driven to assess rock conditions at depth. MFO/ah I I I I I I I , I. I I ··- 1 I I. I I I I I APPENDIX A SUPPORTING DOCU~tENTATION I . . 1·, I I J: .I I I I I I· I I I I I I I I SUSITNA HYDROELECTRIC PROJECT STATUS OF STUDIES (J. Lawrence) ,, ' -t 1i .. t -, -· -, -f -- ----~ -I_., -III -... · oJ SU~lTNA ST/\TV6 _, . -G-€;Ctfec.H N \CAL. E-KPLor:tA 'fro N . -W/\TAN/\ te/lL CNJ7C>N ~16-N Of>f1M l 2.A 11 ON -tSNVI~N MENTAL. -*fl#(~lS:stOI'l -CoNSfRUC1't oN Cos-r.s ~ So#tt:SOlJI eG -LtceN~NGr t -ftNPcNelAL ~ .f<I~K S-(UD\6-5 -'D;A'"DL\N€6- -ftNN-tefa..cpMENl S~rroN R€Pdl:T-seP. 11'1 -~eN OF Wee!, Ft6LD WMK-seR tgl -R.evtew !>P. AclteoJ~<~wt Aa...c Wt>~<K-SSP. &-1 -APA exteRNAL P~er.... R,€Vusw-lPT. ~ 1 -~a\ MINAI<'/ ~IL CANtoN 6S7ft\1A16 -OCT. il "-Pi<aJMirl~'/ WATA:NA e671MATe ~ Nov. WI -fltiN. &eoreo~. ~ ... ~~-2'2 -ft(at.~1 ~Ff ftASl61LlT)' f2Et?a<--r-FE$6 ... tr2. -FJNpq_ J1lAf-r 0 fel>r;~r~rwrj REPtne,--.fMe.rs-~.e. • -~e~ WeEN$€-DY::i.JtAeNTO -MA'/ ~'2.. . . --.• ;--· --- -,. --·•· - - ---·- . c=SU61TNA DEVELOPMENT SELECTiON WATAN~ : -t=ll-L "DAM SSo F"1'. -2. 75 t-1 : l " ·tfs ~oPE. -loS M\w...toN CU. Y.D. -4oo MW \qc::J'S -.fOO MW \qq'- D£Vt L CAN'/0 N : -Al<.a.t DAtvt G:»5o FT. -400 MW :2c:oo . l . .. -...... s-: -.... -· - --: -.j.~ ;- -Aef.<.-65 IW1~N~L P~€L .. I f€8. lGlf?l . I ~ '"' A-.'r AN A_ <;J _nO,.e~ s 2 • ~ t\ : \. 'I ll( .s ·!fr'\ ~---,.F"' w-1. ~-,, 2.) .. : 1 v 'b/ ~ '---lNeiJJRS f=l~etSc$~ ttJ sef>M\C ~1U1>)' · -N\1"~o6(arl SUP~<;f\1\J~ION ~oet.GM (. CWl LLWA '/t6) -LoW 1..£.\fet.,. OU"Tlw~T. ~6N C£Nc.eprs '-MUL-rl-leVEl-lriTAK6 ~6tN ~C€P~ -Ct>N~Iotf< 6A~T.t--l FILL. "DAM A.i :D.c... -WJ><fANA ~\Or\1-""f est:,f-lEDU I e.. toQ... ~M -l't\C,L\J'QO DC.· tN L\C6N56 APPL..\eATtoN -'---· -· --~--. . -1 ....... -·-•• ! i--.• . -ACR.tf'::> GXTtRNAL PA~t..J ·~ - f c e. t q 'B" 1 ' -7ALK€£TNA. -r-H~U&T --kDS --7 . ---t;~\TNA F6ATUQG . . ~ FL..o"-r t N~ 6~H Q\JAKS __, 9~lOFt= 'NAfANf' -ANbt-~\"(6 'bol<l"f~ eoMTPCf t11 NNE.L~) __, ~a.J '-'1 CHANN E.(., -ALLUV\\JM I?J€P1"J4 ) (Go Ffe{l DAtA~ 't>6Vll CAW'/oM ~ c?\-\-6~ z.oNes WA&ANJ:\ -UN~Gr~OONO P/1-\ -'5U~FAOE-P/H AL.. -r. ~ ~V\Lt.,E-:>EOrtoN -Co~~~~ --•a .--·w a .. ~ .~ ~ .. -· ~ .._ ··• -.. --· -APA. E.X\eRNAL ~NEL- · JUN C I qb"l • I -WATANA :-~e;; CftANN~L. 6XA-oAA1low l -UN~~UNt> fJjH 6xPL..OAA1'tON -~AL..\(e,E,TNA 7HRus-r I suc;rJNA fet\1"UR6 INVe=!Tlt:;rA. "Tr of\l~ -~GNI OFF 7-0N'S EI\R.,-1-t &.UAJ<6-s . ..., OP..OVtt .. J .... 6 OftM SeJ::lTI oN t:::'OR WAl~~ l :2c7S'H: tv uf:s SLOPs) -tvt-rt<.oertsN S\JPaeSA-ru~ATic:lC\1 . lSPIU..WA-ts) -DoWN~-T~M Gf.<.OS& ON (SPlU..WA "')'dQ) t . -tbwNS1~ WA1€ce QtJ~-ry (%olrl1 ~-rA.-n~~. ·. M~f'HOL..OG:f't. ftSHERlee=> J ' \ a I t, • \ H> . \;,_ .... ~ ., I ·l I i ----·~-• .r--.. ··-:----.... .............._ ,.--·~-· ... PUTE 7.1 GENERAL ARRANGEMENT • • ' t • ·-~------------------------------------ ·-·----...------------------------.. SECTION A·A ·· ' . .. . . --------------~--- --·-·-!--.. SECTION B-8 • -----I I, --.. --• • GENERAL ARRANGEMENT ltAU_IA • • , t • • - 0 ~ ... 0 ~· t --- • -·~· -- • SECTION A•A l&ll[!l .. ·- CQlTfi:!IA ~~;ce ~II.I..WA'I" oe!afQI( ~---"--IIIIJlDCI.C.P. tMUIC.tlo.II;:Y, :.I'IU.WA.V IM'kl~ l'U)OO -~U IIC:~Q\OIR. ~ IA.blt.II.N -..,l\Wil·~-bll:l)· ~lt'YOIIt ~~M~ 1.1twi,. W\TM. ·so~ .::.__ ·- • I I I I I I I I I •• I I I I I I I I I SEISMIC STUDIES (V. Singh) -- ~ ~ :D 0 0 ,.. -< 0 m n 0 z "' c r- -4 >-z -c 0 -& g ,. ~ II a t -~ - .. ·~ ,• - ~ .. ' .. 1004 Earthqu•ke Rupturt Zone · · · --- ( ~ . '. ' ------------ .. Zone of low Historic Seismicity Plate Motion Relative tq North American Plate NOTES 1. S#t Figure_6-1 for IOGation of Section A-·A·. 2. Geolovh: date aoorcea included in thoH c:hed in figures 4·1 ttnd 5-1. · 0 I Prepared by: Woodward-Clyde Cpnsultants, 1980 SCHEMATIC TAlKEETNA . TERRAIN SECTION 50 100 Milt F I J 0 60 -I I I I I I I 10 I I -.... " ' • . . . . ·r ... J~· , . ... . . ~ . .. :~- . , ... ~ . . : ·~. . ·; .. ·.e;:. .. . .... . . . . - • ,. . .. - --. - LEGEND --Indeterminate _. A fe~ture -·-Indeterminate • B feature ,. -o-indetermin.te • B t. feature NOTES 1. Explanation of feature c:tassifica.tion presented Section 8.2 . 2~ Explanation of alphanumeric: symbol presented in A~dix A. DEVtL CANYON SITE SIGNIFICANT FEATURE MAP 0 1 2 Miles cg: ? \ 0 1 2 3 Kil I I I. I I I I I I I I I I .I I . _-·t-(. l l--... .. ./ • " .. J \ , ._ji -_..;-.f ,.--~ I I' l i ~-. \. /iJ~· ../.~ff 1 'i· .. i .. ! . , .. : I "" '~~ ~,:-.::: ~ ... '. ~ .:--. ..., DEVIL CANYON DAM SITE . -·--~- • .. .... ___ __. ______ " '="' •• _, '· ! . / .. ~ . / . i :. ~ ,;:o:p .;~· ' ! 0 ... ~_, --,~ ~-... . ·; . .. ? ~--l .. . .: t. . I ..... , : . .. ~--:,. ..... 0 0 .I I I I I I I I I I I I I I I I '1. ' I I GEOTECHNICAL FIELD EXPLORATION ( S. Thompson) - I I I I I I I I I I I I I I I I I I I 1981 WAIANA P.ROGRAM 8DDITIONAL WORK 1) GEOLOGY MAPPING & EMPHASIZE SPECIAL FEATURES / 2) DRILL POWERHOUSE AREA * 3) ·RELICT CHANNEL MAPPING, SEISMIC LINES * 4) ROUNDED SHELL MATERIAL UPSTREAM OF THE DAM 5) RESERVOIR SLIDE POTENTIAL RECONNAISSANCE NOTE: * RECOMMENDED BY APA EXTERNAL REVIEY/ BOARD APA PANEL RECOMMENDED DRILLING TO DETERMINE MATERIAL PROPERTIES IN BURIED CHANNEL. · iERVAL 100 FEET ·.t_•, t ,_., fQOr CO~HilUP<; 11CAI.. OATUM OF 1929 i. GEOlOGlCAl SURVEY lORAuO 80225. OR RESTON, VIRGINIA 22092 AINn sYMBOLS 1s AVAilAI!LE ON REQUEST I n ~ _.J8 .;./ l;,... ,• ,,:/' ' / ~ "' Borrow Area BORROW AREAS ---WATANA '" i 1Conttoi ' ROAD ClASSIFICATION : Toc"';;r;; laio.cn 1r No roods or tra•ls m !his area ,Un•vcrs. ; lO.OOO lOOOm ,;one6. TALKEETNA MOUNTAINS {0-4). 1 Land ~n ALASKA,pr1'1etc · Foho$'2 N6245-W14830j15X30 1951 Mllf(JII ~1$1()1;'; l"t\5 I ~l I I I ! ~f~oo l .IOo I 'IVATANA SITE . . cv/ , f ~ I 1980 GEOTECHNICAL INVESTIGATION 0 PREVIOUS WORK I • f980 PROGRAM -DIAf~lOND CORE HOLES J----! ... SEISNlC LINES .r. I I II \VAT ANA SITE I 1981 GEOTECHNICAL 0 PREVIOUS WORK I .4 r 980 PROGRAM ··---12 81 PROGRAr~ -r- y' INVESTIGATION BOREHOLES -DIAMOND CORE HOLES I I ! ~ ... . ' . I I SEIS~~IC LINES 1---f 1980 . 1---4 1981 I I I I I I BORROW AREA F )" / / () JJ . . . NOTE: AP17 • I) SECnON SHOWN ON FIGURE _ 2) TOPOGRAPHIC CONTouRS ARE APPROXIMATE t.. 1 , Previous Work r--...., 1981 Work 198'! SEISMIC LINES SCHEMATIC WATANA EXPLORATION ----- -1 L. BH-1 BH-3 1000 NORTH ABUTUEHT ZIOO IIOC tOOO 1 PREVIOUS 1981 -•• --- BH·6 f;;i-i: ~ SllO. Cll IIOT1'C5il 7CI CIS SECTIOt! A-A LOOKING U/S N as• W • ftiWR'I £DQf; ·I I SECTION B-B LOOKING U/S N 4~ W ---- SOUTif ABUTMENT aoo • • aoo "CC ~ t ---, K,jU .• l'lllT GEOLOGIC CROSS-SECTION WATANA -' ' -- •, BH-12 I I I. I I I I I . I I I I I I I I I I, I VERT I CAL DEPTH BELO\·J ROCK SURFACE < ()I . - "..] 50 1 l::f\ I -1 t::O I _,~u -' • 150' -~Jt::n' ~JV 250' -350' 350 1 -450' 450 1 -550' 550' -650' SITE AVERAGE vJATANA RQD SUf·1r'!ARY FEET DRILLED 944.7 1472.0 753 I L~ L~67, 7 338.2 233.0 196,8 4405.8 RQD % S"Cll Lio 61% 74% 80% 83% ..,6c;' I IC 03ct 0 Ia 67% DATA BASE: DH-1.~ 4.~ 5.~ 6,~ 7.~ 8.~ 9.~ 10.~ 11.~ 12.~ 21.~ 23_, 24.~ £8. BH-2.~ 6_, 8. RQD SUrMARY TABLE % WITHIN RANGE 0-25 25-50 50-75 75-9C 95-lDO __ ._. __ ._ _________ .-a_::::;. _______ ,_. _________________ ~--------..... -----"-'-~----,_- 1lo;- .... '" 12 25 10 17 I I I • BOREHOLES BH TEST PITS SL ft.H DEVIL CANYON SITE PREVIOUS GEOTECHNIGAL INVESTIGATIONS • AH-G4 .. <!' "· I •tOO ~·· I\~ _) I I I I I BH-2 DEV1L CANYON SITE 1981 GEOTECHNICAL INVESTIGATIONS PREVIOUS 19cl1 • BOREHOLES 0 • TEST PITS :6 f--f SEISMIC LINES r---i ----- t'l)OO 1400 IZOO NORTH ABUTMENT l'OO 600 PROJ£CT£D zoo' Cl/S PREVIOUS WORK 1981 - BH-5b . BH-1 BOTTOM ~0' U/$ LOOKING U/S N lie E -· -.. - DH-1 (PROJECTED) BH-3 I SOUTH ABUTMENT BH-5a 100 , ICAU Ill nn l't£F£fa!CES: l flUfttAU OF RECLAt.t.UION. 1~60 ~ CORP$ OF [MGIIIEERS • 197S ~ $01.1'-0 15ecl Wvt:STIG.A'~ GEOLOGIC CROSS-SECTION DEV~LCANYON -- BH--7 BH:4 B()TJOW 250' DIS - I I I I I I I I I I I I I I I I I I I VERT I C.A.L DEPTH BELO\~i ROCK SURFACE 01 -. 50! 50' -150 1 ~ 150' -· 250 I 250' -350' 350' -450 1 450' -550' 550' -650' 650 1 -750' SITE AVERAGE DEVIL CANYON RQD SUf·1t·1ARY FEET DRILLED 477.60 924,90 727.70 626.1 412.8 223.9 128.8 "7 L} ~ :> • .,., 3556.3 ~ ~ .. . , ,, . RQD SUt~t:ARY TABLE I RQD% 72% 76% 81% 87% 91% 90% 85%: 85o; fr::. 81% % ~ITHIN RANGE Q-25 25-50 50-75 75-90 · 90-95 £5-lOC ___________ ._ ___________________ ;_ ... ___ ..... __________ .., ________________ ._.._, __ ..., __ CE 05 1lJ -loo • 22 1~ _.,., 38 .I I I I I I I I I APPROACH TO SPILLWAY DESIGNS (J. Hayden) I I I I J, .;, I I I I '1 I I ·I SusrrNA HYDROELECTRIC PRG~Ecr I PROJECT FLO\AfS I I • I INFLOW REIURN PERIOD YRS, ; I . IMEAN ANNUAL 1 IN 50 1 IN 100 1 IN lOJOOO PMF (DesIGN) TABLE 1 -RIVER FLOv!S (Fr 3/S) WATANA ANNUAL SUMMER PEAK PEAK ' ! ~,· 36)000 I 84., 000 i 92JOOO 1156)000 ! 1310,000 I ·- - I I I * WITH WATANA DEVELOPMENT UPSTREAM. I I I I I I I I .!J N A-rtJ RPt '-Fl-IJ W .ANNUAL SUMMERi PEAK PEAK : t .!! : 41~'000 ; 53J 208 ; 54)000 ·140)000 325)000 I l I I l -I '· ! -l I I I I I I TABLE 2 -ROUTED FLONS FOR DISCHARGE FACILITIES (FT 3/S) RETURN PERron YRs. WATANA DEVIL CANYON 1:50 · DIVERSION CAPACITY . I 1: 100 ANNUAL .YfATANA RESERVOIR STARTING LEVEL AT 2172' (HIGHEST SIMILATED TIME LEVEL) I I I I I I I. I I I I I 1:100 SUMMER 1:10;000 PMF 120)000 270)000 50;000 D, C. N0Rf.4.AL MAX-OPERATING LEVEL BOTH RESERVOIRS AT NORMAL MAX. OPERATING LEVEL BOTH RESERVOIRS AT NORMAL MAX, OPERATING LEVEL BOTH RESERVOIRS AT NORMAL MAX. OPERATING LEVEL 1) FIGURES TENTATIVE -OPTIMIZATION STUDIES UNDERWAY, I I I I I I I I I I I I I I I I I I I ~BLE 3 ~ DISCHARGE CAPACITY OF OUTLET FACILITIES CFT 3;s) FACILlTY Ave. RIVER FLOW MAx. AvG. MONTHLY FLOW CJUNE) MrN. AvG. MONTHLY FLOW (filAR) SeRVICE SPILLWAY AUXILIARY SPILLWAY EMERGENCY SPILLWAY LOWLEVEL OUTLET FOR) COMPENSATION FLOW ~ MAX, CAPACITY ) EMERGENCY DRAWDOWN YIATANA 7)860 23)100 890 33)000 giJOOO 150;000 10)000 24JOOO 33)000 D.C. 8)960 26)200 1)030 45JOOQ 45Jnco REMARKS 1:100 YRa RATED FLOW LESS 75% POWERHOUSE. 1:10)000 YR. FLOW LESS 1:100 FLOW (NO POWERHOUSE AVAILABLE). PMF LESS l:IO~DOO YR. FLOW (NO POWERHOUSE AVAILABLE) I AT 100 1 HEADr I AT 600 HEAD. Sc:RvicE SPI LL~ti,~Y USED FOR EMERGENCY DRAWDOWN, I I I I I I I I I I I I I I I I I I. I DEVIL CANYON LAYOUT STUDIES (R. Ibbotson) ., -----. -- " t • .. ' \ ··, 1 ....... \ ' I I ', \ J , ,' ...... -, ' \ -- .... _ •• ,..otjo • . . ,e. ···'··- •• - ie.oo ,...._...__ - PLATE 7.1 ALASKA POViU AUTHO~rrt J ,..,.,,.., ... .,..,., .. t«"tltt •••u-c-•· OE.VIl.. CAN'iON SCI-tEME. I FLAW "'4o SI:CTtOH - --.. -11 .. , .•.. 1. • .. .. ... ................ ~ .. .... "' -·-· .. -............... ..... a .... ·- w.~------------------------------~ ... 1----------------- -u.L------·-------------·-·-·· OAM P~OFILE (LOO~ UASTii&AM) 11~ 1--------- IIA L------------·-. SECtiON. .T~Q.l) SPU .. ~WA.V ·-,.·---·~ .. • t I ;.,~ ,,,.,,_.,._, _____ .....,._...~~·----------~--------------- - '""_ . ...., ___ _ t OE.VH.. CAN'IO).l SC~EMC. ' SECTIO~~ -- • • • • \ ""GENERAL ARRANGEMENT 10 I t ? f a ~----~~----~--_.--~~~----~----------------~------~------~--~----------~ ·~~ --.... t -· - * ~· . JOO,.l••wu ~oou.r'Gia MA41' -~ .. ·1-"~"0 .. -~""' ~T ...... P\..A'TE 7. 3 AUS!CA. POW£~ AUTHOI:ITY ....... '" -···· , •• llt ,, .... t, ... _._,_, _'Y" .... --.·-.. ·----· _....._ ... _..,...... .... ....__ ...... ., ...... . .. .. .. ~· ' ' GtNER - ~ l_~~------r-~~~~~~~~-.~~~.~~~~~~-.~M~O--~~~~~~~. ~~~~~-i~~i~~~~~~jU.-~~"rt;- llOO 1109 gwW..& 11'4 PUT SECI!QN B•B ·- SECTION A·A (fMAU 11'11.\JIAl) SECTION C·C. -----· -----------------: ----·-··-..... ----~ ---.. -~ .. ----,-,L(-·--· _._,c.;_ ___ _ -~ . StCTION F-F ---/f~·-- SECTION E·E ~.n 'fv't .. !! .. 10 ""~"'''"Co.IIC. AlASKA POWflt. AUtHORITY DEVIL CANYON SCHEME a - ! I I t ' t q ! . +'\ f 1 i • . \ I ( ' ' ---- • I 1 -l i'IIITtlt.{Ao [ii:..lll4'/ . l- t • . . . ' ···-·.. • .. l'lt.ATE: 9..1 itrr · ALASKA lib\\'i'k AtJTHOi:ltY lk~nl ....................... t nauec• D£\111.: CAN'I'ON SCHrt.it ''IT -~! T ;l Jl ''1, I. L •. ' ; -; ! -~ i : l.w ·. } ~ : t ! • + I .:..I; : : -11 . ~ . } . ... - .. it • fi t·l ·-·\ -,~..-r,_{;-,,.~p·r-"'!'Y --· -~--~··~,-·~x--~ --,~-T. ~. m H ft . i . ft ~ ~ i : . . t I I ! 1: I a: '. ! ! . ,. Jl l ~I ~-~ ~ I I~~ ! • I trW· ' : l't;t' I. d! ' l -~ § ~ i• i· §. H i· §• I 1·1 ~ .i . . . i j_! : ~ : ; i " . !: 'F j: J; : .... 15 z i !· /· t I I. I . . . I It ,., t I I i ll ~i m Ill'>~ .. H'i'i D' .... t - ~ .... 5 §· 8 'i i a B A ft ~~ .. ! ! 0 .. f ~ ~~ f·~ it. i I M ~-i !l l I J I I $ a -,... ....... -·· .. - ~-~~ . - . ' -~"' " . D· !.,.;;...,..;....,IIWI..L.'-.-'~~~~t .... .., .... ,.-__ JJ"'•tio!ll-· .. tti ..... t&!l ~ ........ _., ... -------~--~~l:~~----------------------••••·••·--•t--•••-•-w I 1 -tiL It::' • 0 • l _, • ! t . i I l i I i ..,.I 'i } i ... l . ... ' 1 • i ' t . i • •• . .. : . • i I ; i ; .. \ ·i l ' . u • ' I I I -! .: I ! . . IP .. . ! . i ~ i : 1 .. ..... .. J. . ,, " ,·, . ·' I ---' •• ---.... •• tW1 UN au• ~ nH I tiM a i ' ilU. i .... .f .. lio -----._.__ ----............ ...... .......... ·-:riGa ... -...., ..... .,4_.,.,../f'-~--~-:· ........ "'-- t ' ' t ' -- lUI . ~ t:~· .w.•\ 1\J.; -~ f . lUI .. liU .fit' •t 11 liM .... .... tHo\ .r-J .... u.. ·""' ·~"rt . ... (. .. M .=<iO,. ll>o 0 It \0 .. ,U. ~ ~' "t(f~ A>cci.U. (fl4) - I . . I I 1\ I I I I UiV!~ CANYON ARCH DAM ANALYSIS (R. Ibbotson) I I ~ I It I I I I I I I I ~. I I I I I I I I I ,, I I I I I I I 4 -DESIGN CRITERIA 4 .. 1 -Material Propertie!_ a) Concrete Frost Resistance Concr·ete Strength {365 day) Unit Weight Static Modulus {)f Elasticity (susta'ined) Dynamic Modulus of Elasticity (instantaneous) Poissons Ratio Tensile Strength: Static (for estimating cracking only) 5% of strength Dynamic Flexural 15% of strength Thermal Properties: Conductivity Specific Heat Coefficient of Thermal Expansion Diffusivity b) Foundation Rock Deformation Modulus (sustained) Poissons Ratio 4. 2 -Temperatures ( °F) Air Temperature: Mean Annual 0 High Mean Monthly - Low Mean Monthly Highest Mean Monthly Maximum Lowest Mean Monthly Minimum c 5,000 psi 150 1b/ft3 3 x 106 psi 5 x 106 psi 0.2 250 psi 750 psi 1.52 BTU/ft/hr/°F 0.22 BTU/lb/°F -6 5. 6 X 10 ft/ft/0 f 0.046 ft2/hr 2 x 106 psi 0.2 28.9 55.0 4.4 63.8 -3.6 I I I I I I I I I I I I I I I I I I I Highest Maximum Lowest Minimum Lowest Difference Between Any Nean Monthly Maximum and the Corresponding Mean Monthly Minimum RESERVOIR WATER TEMPERATURE Depth Below M 0 N i H Surface (ft) 4 5 6 I 8 9 10 11 . 0 -50 ~_f 32 !!& 51 53 45 39 32 70 to Reser- voir Bottom . 39 39 39 39 39 39 39 39 12 32 39 91.0 -48.0 -14.5 1 ~2 39 The effe~t of solar radiation has been at this stage neglected. Grouting temperature of vertical construction joints: 39°F 4.3 --Earthquake 2 3 32 3Z 39 39 For maximum credible earthquake conditiors •wo vers~ons of the mean response spectra for the Pen1 off zone, developed by Woodward Clyde Consultants have been used. Peak Ground Acceleration 0.5 g o. 4 g 4.4 -Hydraulic Data . Reservoir Water Levels: Normal Maximum *Normal Minimum 1:10,000 Yr Flood Level Probable Maximum Flood Damping Factor 5% 10% 1,455 ft 1,430 ft 1,460 ft 1,465 ft I I I I I I I I I I I I I I -I I I I •• Effect of tailwater, silt deposits, ice load, and uplift loads (internal pres- sur~ within th~ dam) have been neglected. *Thts was assumed as 1,295 ft for stress calculations. However, minimum operat- ing level has now been maintained at 1~430 ft from standpoint of firm energy considerations. Hence, this condition will be far less extreme. 4.5 -Loading Combinations: a) ~~~al Loading Combination -Combination of basic loads that can simultaneously occur during time design life of the dam (self-weight, temperature and hydrostatic load condition.) b) Unu~ual Loading Combination -Combination of loads that are possible, but which are unlikely to occur during the design life of the dam (probable maximum flood conqitions.) c) Extreme Loading Combination-Are related to earthquakes. The loading combinations cases are given in Table 4.1. 4 .• 6 -Factors of Safety: a) Usual Loadin~ Case UL-1, UL-2 -Compressive stresses -F.O.S. > 4 -Tension stresses -not allowable.* b) Usual Loading Case UL-3, UL~4, and Unusual Case -Compressive stresses -F.o.s. 2 3 -Tension stresses not to excec; 250 psi. a -Tensile stresses above 250 psi are to be redistributed to other resistance mechanisms by local joint openings. *These factors of safety correspond to the trial load method and are in line \'lith the previous practice.. They do not necessarily apply to ether methods of analysis • ' ~. . -I • f ~ • • . "' ' ~ '\ . . ·: . ' ,;')~ . \ . . . \. )• ; ,. ·: ~ ' • : • CJl • • .4 I I I I I I I I I I I I I I I I I I I c) Ext~eme Loading Case EL-l, El-2 -Compressive stresses -F. 0. S._ ~1. -Tension stresses exceeding the tensile strength of 750 psi are to be redistributed to other resistance mechanisms. In case of horizontal tensile stresses across the arches the dam should be considered as a set of unrestrained cantilevers 50 percent of full height, because of opening vertical construction joints. ·. ---, .. ----------- TABLE 4.1 I CombinatJ:cn ~lass u 5 U A L Unusual Ext reme load Combinationf CombinatJ.on Number 1JL..:1 UL--Z UL-.} UL-4 1JNC-1 ll-1 t.l-Z 5 Df.AO l 0 A 0 X X X X X X X T A B T A I Air and Reservoir fcbt•uary X 5 r. I Watur l empeJ·atun~s April X f. L 0 Reservoir Water 1,455 X X X X A 1,46:> X D Levels 1,Z~') X L 5 1. 4.)1) X X 0 A 0 I 0 y I N A t-1 n.s c c I Ma~imum Credible 5% Damp. X A c s E l f..arthquake fl.4G 5 0 10 Damp. X A 0 s •- 1 I I I I I I I I I I I I I I I I I 5 -METHOD OF ANALYSIS 5.1 -General The Arch Dam Stress Ana 1ys is System (ADSAS) program which is a computerized version of the trial load method, is used for static and earthquake dynamic analysis. In the analysis the arch dam is assumed to be a continuous structure. The dead load is applied in the cantilever direction (construction joints grouted at full height of sections). The computer program SAP IV is used for the unrestrained crown _cantilever analy- sis in cases where the dam is subjected to ~trong earthquake motions, causing opening of the upper part of vertical construction joints. 0 5.2 -Method of Definition of Loads a) Temperature Load The two-dimensional heat transfer program (heatflow) is used for determi nation of temperature d i str i but ion in the dam body. The USBR Engineering Monography N34 is used for computation of the amplitude of the sinusoidal cycles, (Annua 1, 15-0ay and Da i 1y). The temperature 1 oads input into ADSAS are presented in Appendix A. b) Hydrodynamic Load The hydrodynamic pressure due to horizontal earthquake on the dam upstream face (nadded mass 11 ) is defined by using Westergaards Formula and is reduced to 60%, due to the effect of narrowness of the gorge, inclination of the dam face and water compressibility (see Appendix C.) I I I I· I I I I I I I I I I I I I I I 6 -ARCH DAM GEOMETRY The arch dam abutments are founded on the sound bedrock of the canyon. The sound unweathered rock is determined as generally 40 feet be1 ow the bedrock surface and the foundation is trimmed so as not to cause an abrupt change in the dam profile and hence a concentration of stresses .. At the bottom of the valley, the dam sits on a massive concrete plug which can adjust to any disconformities of the bedrock at the valley floor without changing the geometry of the dam. Sound bedrock does not continue above approx- imately ·elevation 1350 feet on the left bank and a massive thrust block is con- structed to take the thrust of the upper 100 feet of arches. A similar block is founded deep in the rock on the right side in order to preserve the symmetry of the dam profile. The dam geometry is shown on Plate 6.2. It is a double curvatur.e structure with the cupola shape of the crown cantilever defined by vertical curves of approxi- mately 1352 feet and 869 foot radius. The horizontal arches are prescribed by varying radii moving along two pairs of center lines. The shorter radii of the intrados face cause a broadening of the arches at the abutment reducing the con- tact stresses. The dam reference plane is approximately centra 1 to the bottom of the va 11 ey and the two center confi gur at ion assign l anger radii to the arches on the wider side of the va 11 ey thus pro vi ding comparab 1 e contact areas on both sides of the arches at the concrete/rock interface. The longer radii will also allow the thrust from the arches to be directed more into the abutment rather than parallel to the river. The net effect of this two center layout will be to improve the symmetry of the stresses right across the dam. ' The crown cantilever is 635 feet high. It is 20 feet thick at the crest ar1d 90 feet thick at the base. The bottom mass concrete plug is 50 feet high. The slenderness coefficient of the arch is equal to 90/635 = 0,142 and the radii of the dam axis at crest level are 710 feet and 780 feet for the left and right angles of the dam, respectively. The central angles vary between 51.5 DEG at El. 1300 and 25 DEG at the base for the left side of the arch dam and 58 DEG to 30 DEG for the right side. The ratio of crest length to height for the dam is 1260:635:: 1.98:1 {thrust blocks not included). I I I I I I •• I I I I I I I I I I I I The left bank thrust block is 105 feet high and 170 feet long at the base. The right bank thrust block has a maximum height of 100 feet and a length of 155 feet and is adjacent to the spillway control structure, which will behave as a continuation of the thrust b:ock, transferring the thrust directly into the rock. I I I I I I I I I I I I I I I I I I I 7 -STATIC LOAD CONDITIONS 7.1 -Dead Load !n all analyses, the vertical construction joints within the dam are assumed to be ungrouted and hence the weight of the dam is considered as confined within the cantilevers, with no distribution through the ar·:hes, and directed verti- cally downwards into the foundation. 7.2 -Hydrostatic Hydrostatic loadings induced by the reservoir at specified levels were consid- ered in all load combinations. The effect of tailwater and uplift pressures will have little effect on the overall stresses and are not considered at this time. 7. 3 -!_emperature (a) Solar Radiation · The dam orientation, running north-south, and the narro\'f valley will cause solar radiation to have only minor effects on concrete temperatures and hence stresses frDm radiation will be neglected at this time. (b) Air Temperatures Because of absence of temperature records, temperatures at the Devi.l Canyon site have been interpolated from records taken at two stations: Summit (El. 2405 feet) and Talkeetna (El. 345 feet). The stat·tons are equidi.stant from Watana and their average altitude is similar to river level at Watana. The temperatures from the two stations were averaged to obtain the following temperatures at the dam site: I I I I I I I I I I • I I I I I I I I I (c) AMBIENT AIR TEMPERATURE (°F) Mean Annual ............................................. 28.9 High Mean Monthly •.......•...•.....•.....•....•....... 55.0 Low Mean Monthly ...•......•... : .................. ~...... 4.4 Highest Me an Month 1y Maxi mum . . . . . • . . . . . • . . • . . • . • . . . . . . 63.8 Lowest Mean Monthly Minimum ••...•........• H ........... -3.6 Highest Maxi mum . • • • • . . • • . • . . • . . . . . . . . . . . . . . . . . . . . . . . . . 91.0 Lowest Minimum ....•..•....•••......•••.......•.•.••..• -48.0 Lowest Difference between any Mean Monthly Maximum and the Corresponding Mean Month 1 y Mi n i mum . . . . . • • . . • . • . . • . . . . • . . . . • . . . . . . . . . . . . 14. 5 Three sinusoidal temperature cycles-annual, 15-day and daily are developed based on USBR ENG MONOGRAPH No. 34. The temperatures obtained are as follows: EXTREME CONDITIONS USUAL CONDITIONS Above Below Above Below 0 Mean (DEGF) Mean (DEGF) Mean (DEGF) Mean jDEGF) Annua 1 15-day Daily 26.1 28.8 7.25 Reservoir Water Temperature 24.5 42.15 7.25 26.1 15.15 7.25 24.5 22.95 7.25 Average monthly reservoir temperatures are given below. Temperatures throughout the top 50 feet are as shown and below 50 feet they vary lineraly to 39°F at a depth of 70 feet. I I I I I I I I I I I I I •• I I I I I (d) (e) Month April May June July August September October November December · January February March Grouting Temperature 32 32 46 57 53 45 39 32 32 32 32 32 Below 70 ft From Surface (°F) · 39 39 On account of the cold climate and the possibility of freezing, grouting temperature was selected at 39°F~ as low as considered practicable, in order to reduce tension in the dam induced by shrinkage at lower tempera- tures. Temperature Distribution The temperature distribution in the dam body was determined using the two d irnensi on a 1 heat transfer program "HEATFLOW' obtai ned from the U.s. Department of the Interior (formerly USBR) and was input as a uniform tem- perature combined with a linear distribution as described in Appendix A. I I I I I I I I I· I I I I I I I I •• I 7.4 -Load Combinations Static analyses were performed for the following normal loading combinations: UL-1 -Hydrostatic and dead loads at normal reservoir level 1445 feet UL-2 -Hydros~atic and dead loads at maximum drawdown reservoir level 1295 feet UL-3 -The same as UL-1 plus temperature (February) UL-4-The same as UL-2 plus temperature (April) UL-1 and UL-2 Conditions The cantilever and arch stresses along the face of the dam are shown in Figures 87-1 to 87~4 in Appendix B. In both the arch and cantilever directions, the _entire structure is in compression and below the allowable stress of 1250 psi, except for a few isolated areas where small tensile stresses occur. Maximum (compression) and minimum (tension) stress for conditions Ul-1 an UL-2 are shown in Tab 1 e 7 .1. The arch and cantilever stresses for loading combinations UL-3 and UL-4 are shown in Figures 7.5 to 7.12. The maximum and minimum stresses along the rock/concret~ interface and in the dam above the foundation are given in Tab 1 e 7 .2. 7.5 -Conclusion (1) Under hydrostatic loading, minor isolated tensile stresses occur up to a maximum of 97 psi. ( 2) In bo;-;1 cases with temperature 1 oadi ngs UL-3 and UL-4, the compressive stresses are below the allowable limit . I I I I I I I I I I I I I I I I I I I (3) In UL-3 case, tensile stresses are acting in isolated areas. The tensile stresses is possi b 1 e to e 1 i min ate by refining the shape of the arch. (4) In UL-4 case, the crest of the dam is in the arch direction subjected to almost axi a 1 tension. Ten~i 1 e stresses up to 200 psi are found at the whole height of the crown downstream face. . Prevention of these tensile stresses is possible only by application of special measures such as: -Low closure temperatures at the upper part of the arch which may be obtained by using closure slots between adjacent blocks filled up with concrete in spring time when the blocks are at minimum temperature. -Thermal insulation of the downstream face. -Prestressing the upper part of the dam by means of flat jacks. I I I I I I I I I I I I I I I I I I I Arch Max Min TABLE 7.1 EXTREME ~mGN!TUDES OF STRESSES AT ROCK/CONCRETE INTERFACE Loading Combination (stresses in psi) UL•l 792 (D. El 1100) 23 ( U . El 1 000) Cantilever Max Min 722 (D. El 820) -27 (D El 1370) Principal t·1aX 1 049 ( 0. 1 000) Min -140 (D. 900) -indicates tension D indicates downstream face U indicates upstream face UL-2 432 (U El 900) 3 (U El 1 000) 760 (U El 900) -97 (0 El 1200) MAXIMUM STRESSES IN DAM ABOVE FOU~DATION Arch Max Min Cantilever Max Min UL-1 958 (U El 1100) 182 (D E1 1 000) 575 (D El 1000) 0 {0 El 1370) UL-2 · • .~ 548 (U El 1000) -36 (D El 13i0) 542 (U El 1000) -44 (U El 1295) I. I. I I I I I I I I I I I I I I I I I · Arch Max Min Cantilever Max r4in Arch r4ax Min Cantilever Max Min TABLE 7.2 EXTREME MAGNITUDES OF STRESS ALONG ROCK/CONCRETE INTERFt'.~g_ Loadi~g Combination UL-3 (point) UL-4 {point) 747 (U El 900) 381 {D 1100) -182 (U El 1455) -157 (D 900) 689 (0 El 820) 804 (U El 900) -393 (0 El 1370) -281 (D E1·1455) EXTREME f~GNITUDES OF STRESSES IN DAM ABOVE FOUNDATION Loading Combination UL-3 (point) UL-4 (point) . 1180 ( U El 1200) 717 ( U El 11 00) -134 (D E1 1000) -268 (U E1 1455) t U E l 1455) 515 (U El 900) 608 (U El 1000) -75 (D E1 1370) -62 (U El 1295) I: I I .I' I I ... I I I I I I I I I I I I 8 -DYNAMIC ANALYSE.S Preliminary assumptions for purposes of analysis are as follows: The assumed . ..response spectra input to AOSAS is from Figure 3-4 of the ~~oodward Clyde Draft Report 11 Prelirninary Earthquake Ground Motion Studies for the Proposed Susitna Hydroelectric Project". The mean response spectra for the Benioff zone is scaled up to 0.5g peak from 0.37g. The damping ratio is five percent. The response spectrum is shown in Figure 8.1. The response spectrum analysis was initially attempted for 1 to 20 modes. A larger displacement mode was encountered on mode 19. The high displacement induced unreasonable stresses in the dam and therefore made the results useless. The problem was re-analyzed using 14 modes of vibration. The response spectrum analysis assumed an instantaneous concrete modulus of 5,000,000 psi. The results of positive and negative earthquake are presented in the following tables. The load combinations are hydrostatic and grvity + earthquake and hydrostatic + gravity + uniform and linear temperature~ earthquake: Tab 1 e 8.1 -Response Sect rum Analysis -Arch Stresses Table 8.2 -Crown Cantilever Stresses The resultant tensile stresses of 2580 psi and 729 psi in the arch and canti- levers, respectively, are greatly in access of the allowable tensile stress of 500 psi. The results of a dynamic analysis of Devil Canyon Arch Dam based on a 0.4g peak ground acceleration, 10% damping, the Woodward Clyde Consultants response spectrum (see Figures 8. 2) and using the ADSAS program are shown on Figures B.15 and 8.16. For comparison~ the results of dynamic analyses for a peak ground ' acceleration 0.5g and 5% damping are presented on Figures 8.13 and 8.14 I I I I I I I I I I I I I I I I I I I The ·change of earthquake parameters to 0.4g and 10% damping has reduced the compressive~ tensile and shear stresses at a 11 points on the dam faces by a factor of 1.58 compared to the O.Sg acceleration and 5% damping case. The case of upstream ground movement {hydrostatic, gravity and earthquake loads), the maximum cantilever tensile stress at the upstream face dropped from 729 psi to 427 psi (at elevation 1285 feet on the crown cantilever). The maxi- mum compressive arch stresses at the upstream face (crown El. 1370) dropped from 3657 psi to 2551 psi. Stresses on the downstream face are much lower than on the upstream. Downstream ground movEment (hydrostatic and gravity minus earthquake load) shows extremely high tensile stresses across the arches (see Table 8.3). The stresses computed are not realistic .. As discovered by field observations and model tests on other projects, earthquake induced ground movement in the downstream direc- tion causes the radial construction joints at the upper part of an arch dam to open. The tension induced in the upper part of these arches is relaxed and the dam eva 1 ves into a set of independent, unrestrained cant l1 evers, deflecting freely in the upstream direction. In order to accord more closely with the actua 1 behavior of the Devil Canyon · Arch Dam, when subjected to strong earthquake motions, dynamic ana lyses on the unrestrained crown cant i 1 ever were pfrformed using the computer program SAP IV. Model test on other arch dams with simulated radial construction joints~ per- formed by 11 I sr.-tES" have shown that opening of the joints take p 1 ace over the top 1/3 to 1/2 (depending on the narrowness at the gorge) of the dam, while the lower part remained intack. The ana lyses are based on: (1) The Woodward Clyde Consultants response spectrum curves for the Benioff zone with peak ground accelerations of O.Sg and 0.4g and damping rates of 5% and 10%. I I I I •• I I I I I I I I I .I I I I I (2) The hydrodynamic stress di stri buti on as proposed by Westerguard approach and reduced to 60% due to the effect of narrowness of the gorge, inclina- tion of the dam upstream. face and water compressibility (see Appendix C) .. (3) Full reservoir water level 1445 feet computer program for dynamic analysis has been used • The following combinations of earthquake parameters have been examined: Peak Ground Acceleration "G" 0.5 0.-4 Damping Ratio (Percent) 5 10 0 5 10 The results of the cantilever dynamic analysis are as follows: Added Mass (Percent) 100 60 100 60 100 60 100 60 (1) The natural period of vibration 11 T11 is 0.62 sec, 0.15 sec and 0.09 sec. (Various magnitudes of acceleration and added mass have little effect). For comparison, a full height cantilever, which is slender, has been computed. The periods were found 2.42 sec, 0.49 sec and 0.20 sec. The stresses in the upper part of the arch in this case were smaller than in the short cantilever. I I. I ·:- 1 I I. I I I I I I I I; I I I. I: (2) The stresses due to hydrostatic and gravity and dynamic loads are presented separately and in combinations. In Tables 8.4 and 8.5 and in Figure 4, maximum tensile stresses of 880 psi at the downstream face were obtained in the case of 0.5g, 5% damping and full Westergaard's added mass at 170 feet bel ow crest leveL. Compressive stresses at the upstream face at that level are 1100 psi. The maximum tensi1e stresses in case of 0.5g, 10% damping and 60% of Westergaard's added mass are equal to 451 psi. The change of damping from 5% to 10% decreases the maximum tensile stresses approximately 1.6 ·times. Th·e application of 60% added mass instead of full Westergaard's provides a reduction of the maximum tensile stresses of about 25%. In a 11 comb in at ions of dyanmi c J oads considered, the tens i 1 e stresses at the base of cantilever have changed to compressive (except of case O.Sg, 5% damping and full added mass, where tension is reduced to 55 psi) (Figure 8.4). In the case of 0.4g, ground acceleration, the maximum tensile stresses at the downstream face of cantilever dropped to 509 psi 120 feet below the crest with 5% damping and full added mass, and to 272 psi with 10% damping and 60% added mass. The effects of the change in damping and added mass are approximately the same as in the case of 0.5g acceleration. I I I I I I I I I I I I I I I I .I I I i) Arch.at Elv. 1455' STATION FACE E 1000 I E 1143 I E 1259 I E 1393 I . E 1526 I E 1638 I E 1711 I Q E 1714 I TABLE 8. i RESPONSE SPECTRUM ANALYSIS ~ HYDRO + HYDRO + HYDRO + ! HYDRO + GRV GRAVITY GRAVITY + EO GRAVITY-EO r + TEMP + EO 467 3404 -2470 3294 313 1943 -1630 1784 516 3229 -2197 3122 307 2304 -1690 2146 484 2948 -1980 2843 366 2749 -2017 2611 406 2498 -1686 2383 438 3019 -2143 2896 324 2033 -1385 1877 417 2566 . -1732 2376 303 . 1591 -985 1356 342 2232 -1548 1962 274 2513 -1965 2105 576 2409 -1257 2465 267 2574 -2040 2125 607 2478 -1267 . 2596 HYDRO + GRV + TE~1P -EO -2580 -1476 -2304 -1848 -2085 -2155 -1801 -2266 -1541 -1922 -1220 -1818 -2373 -1201 -2409 -1146 I I I I I I .1· I I I I I I I I I I I I TABLE 8.~ RESPONSE SPECTRUM ANALYSIS ii) Arch at E1ev. 1370' I H.YDRO + HYDRO + I HYDRO + I STATION FACE GRAVITY GRV + EQ GRV -EQ E 642 3657 -2373 1000 I 255 949 -439 t:' 707 3222 -1808 lu 1143 I 258 1597 -1081 E 593 2461 -1275 1259 r 396 2247 -1455 . E 416 1634 -802 1393 ' I 518 2558 -1522 E 295 1188 ... 599 1526 I 498 2383 -1387 E 206 1071 -659 1638 I 413 1979 -1153 E 110 1220 -1000 1711 I 374 1449 -701 .HYDRO + GRV l HYDRO+ GRV. + TEMP + EQ + TEMP -EO 4119 -1911 697 -€91 3677 -1353 1355 -1323 2884 -852 2021 -1681 2006 l -430 ' 2323 -1757 1511 -275 2111 ' -1659 1297 l ·433 I 1733 -1399 1266 -954 1345 -805 -•- ·1 I I .. I I' I I I •• I I I I. - I I ' I I ELEV. 1455 1370 1285 1200 1100 1000 900 820 FACE u D u n u D u D u D u D u D u D TABLE 8.2 RESPONSE SPECTRUM ANALYSIS CROHN CANTILEVER HYDRO + HYDRO ·+ HYDRO + ! HYDRO + GRV HYDRO + GRV GRAVITY GRAVITY + E_Q GRAVITY-EQ + TEMP + EO + TEMP -EO 0 0 0 0 0 0 0 0 0 0 109 -581 799 -564 816 56 653 -561 658 -576 98 -729 925 -655 999 222 1021 -577 950 -648 71 -629. 771 -508 892 402 1111 ... 307 988 -430 102 -435 639 -282 792 544 1110 -22 948 -184 223 -142 638 -31 19.9. 575 1026 124 ' 851 -51 383 -19 785 113 917 539 988 90 842 -56 305 -402 1012 -373 1041 722 1541 -97 1508 -130 --.. --- EARTHQUAKE ELEVA11Uff) Of fACE Of DAM ARCH FT. 0.5G u 1455 D ' 5% Damp. I u 1370 . D u 0.4G 1455 . 0 u 10% Damp. 1370 D --· --· .-.. ,_ ... -: .. , .. - TABLE 8.3 DISTANCE ALONG THE ARCH (FT) CROWN ABUTMEtff 0 143 394 638 714 -2470 -2197 -1686 -985 -2040 -1630 -1690 -2143 -1548 -1261 -2373 -1808 -803 -659 -lOOQ -439 -1081 -1522 -1153 -70l -1392 -1203 -919 -512 -1149 -720 -957 -1196 -855 -751 -1267 -887 -355 -341 -592 -185 -589 -774 -578 -306 --·--. . -· ·--- Table 8.4 DEVIL CANYON ARCH DAM RESULTS Of SINGLE CANTILEVER DYNAMIC ANALYSIS fOR 0.5 G PEAK GROUND ACcELERATION 1428 -5 29 + 180 + 144 + 177 + 141 1375 -72 148 + 760 + 604 + 685 + 546 1322 -265 405 +1210 + 960 +1075 + 856 1269 -530 750 +1630 +1300 +1450 +1150 1216 -930 1230 +2060 +1635 +1823 +1440 1163 -1495 1885 +'2620 +2081 +"2300 "+1825 1110 -2295 2785 +2840 +2255 +2490 +1570 1. Resultant stresses are computed for dynamic loads applied upstream 2. 11 *11 indicates maximum tensile stresses; 11011 indicates corresponding compressive stresses at the opposite side of the same level. 3. (-} indicates. tension. -t51 -612 -805 -880* -830 -735 -55 sses at Downstream Face -114 -148 -456 -537 -555* -670 -550 -700* -ll05 -593 -196 -415 530 205 --- s -112 175 139 112 136 -398 688 532 .b13 474 -451* 945 695° -S10 591° -400 1100° 770 920° 620 -21C 1135 705 -S93 510 60 1125 536 !lOS 330 315 545 -70 195 -325 Table 8.5 DEVIL CANYON ARCH DAM RESULTS OF SINGLE CANTILEVER DY.NAMIC ANALYSIS FOR 0.4 G PEAK GROUND ACCELERATION 1425 -5 29 + 143 + 114 + 140 + 112 1375 -72 148 + 577 + 459 + 528 + 420 1322 -265 405 + 914 + 727 + 826 + 656 1269 -530 750 +1233 + 977 +1110 + 885 1216 -930 1230 +1547 +1230 +1394 +1105 1163 -1495 1885 +1971 "+1560 +1750 +1390 1110 -2295 2795 +2130 +1692 +1897 +1504 1. Resultant stresses are computed for dynamic loads ap~lied upstream 2. 11 *11 indicates maximum tensile stresses; 11011 indicates corresponding compressive stresses at the opposite side of the same level. 3. (-) indicates tension. -1'14 -85 -111 -429 -311 -380 -509* -322* -421* -483 -227 -360 -317 0 -164 -86 325 135 655 1093 888 -83 138 109 135 107 -272*' 505 382 456 .348° -251 649° 462° 561° 391 -135 703 447 580 355 125 617 300 464 175 495 476 65 .255 -105 1381 -165 -603 -398 -791 -liS ._ ~- 1.2r-~--------------------------------------------~--------------~ .. I • . 1.0 + ap = 0.21g 0.2 0.03 0.1 . Damping Ratio== 0.05 · . , + . . 0.3 1 3 10 Period (seconds) MEAN RESPONSE SPECTRA AT THE DEVIL·s CANYON SITE FOR MJl,XlMUM EARTHQUAKES ON KNOWN ACTIVE FAULTS .. ---~--•. ...- 0') ...._ ItS (/) ... c 0 •r- 4..J ItS s... <U .-- <lJ u u a:::( r- I'd s... 4-) u <lJ a. (/) 1.2.------------------------------------ DAMPING RATIO= 0.10 1.0 ? 0.8 BENIOFF ZONE 0.6 / DENALI FAULT 0.4 a = 0.37g p a = 0.2lg p 0.2 Period ·(seconds) 0~--------~--~------~----------~--------·--~----------~--------~ 0.01 0.03 0.1 Prepared by Acres, 6/4/81 from data , provided by M. Powers, WCC 1 . .3 .10 MEAN RESPONSE.SPECTRA AT THE DEVIL.CANYON.SITE FOR MAXIMLKv1 EARTHQUAKES ON KNOWN .ACTIVE .FAULTS --.• t.'DJ ---' @II I ot SJNTEGRA.TEO PAl< OF ARCH DAM J+A lNTACT PART OF A.I<C~ OA!'-" -----, \-I'(OROSTATlC ADDE.D MASS -151 -<#l'l -805 -88/:J -8'00 -7~5 545 +Tn7777.m7J.~ .-65 -ss(-e~) (~4-8) "08'2.. -52'2. (-'251) (~55) 441 ,__~~ _221 (·l~S) (116) ~00 1-...:;:::::.-10 (l25) (-105) ~5 J==::::J o'2. s ( 4~'!>) -b7'J'7h.T7777,..& 109~ Q~81) 0.6 G f. 5X DAMPING 0.4-G f 10~ DAMPING tOO o/.2 AODE.O MASS 100% ADDE.O MASS (4 !SO Yo IN BAACK.E.TS) CANTILE.Vl:.R STRE..5SE.S (PSI) . " SE..CTION A-A DIRC:.CTION OF GFlOlJ~ t-AQVEMENT NOTE-; 0 (MH-lUS) tNDICATSS 'Tt:~SILE STR.E~SS Ql {PLUS) lt-.IDICA.TE.S.. 4:;0MPI<.E.S51VE. ST,aE.$5. OE.VIL CANYON ARC\-\ DAM E:ARTl-tQUA.K.E DYNAMIC ANAL-YSlS fiGURE I· I ,, I I I I .,.,. I I WATANA LAYOUT STUDIES (J. Lawrence, R. Ibbotson) I I I "' I I ' I I I I :-':._·.· .. ·. · .. ~-.. :::·. ·<· . ,..~· .. : .· · ... ' ·_.· .. · .. -... · _:_ .· .. · .. _· · .. ' . ·\~ .· ":~ .. · ., : '.: • • • ._ .. _. ~ • -: • ' • • ~ •• ~ • ' < :-. • ~ • • ' f : • • • • • • • . : ••• •• : ' • • • • ·' • • • \ ... -~- l>GV~atT Seu:c;t1~ bf.\fV\ pes lt.SwN ~'*---4------~~ l.-1\ tou-rs f . . . ~----~- ----------- - ,.,... ... / ... ......---··· ---·· ,..._. ... --..... ............._ .,....-··· . . .................. "." ·-.... ~----.-. _____ .,_.,.,. __ .. "!"" __ -.,_ .. ______ , ______ .... --·-------·-----.. --., __ , ____ ...,_.._ ..... __ ....__ .. ..,._,. ............. .. - --.. -• c.~.--- I _..,_ ------- .. ~ .. I 2.~00 t!IOO 'tliOO ~·oo lOOO 1900 OtiiGIIU.\. --· --· ·-------------- 11~00 ...... --.,.~ ··--·· --------·----------- I "tOO 1!000 ··---~------------ 1!:.00 . ··---------·--------------- 14.00 SECTION A-A '\UOO 't'ZOO '1100 'ZOOO -· .. ___ ,., ________ _ 1900 1800 l!Ulf'£ noo tGOO 1!>00 1400 SECTION B-8 Pl.AT'E 7.2: WATANA t..11\IN o.t.t.1· tAll. SCHE\t!!S1 ......... ·-t 7 t • t 4 s t It F£FF rrrl-·rt -----.... _ .. ___ .._, _________ .........,.__. ___ .. ------------- I ~ ,,s,o 1..::0 1330 lo!!QO 1750 I'JOO IG50 1<000 I !>SO ISOO t4SO 1400 - !I•WIIf.f.l.l\lc:UOIT1!0~ .40'w. !>0'.., IP._ '!>~'"'• AO~.--· SECTION A·A sc...ut•A 0 t -............. ___ .. __ .,...._ .. ,_ .... ~-.. ·-·. --- SPILLWAY PROFILE ' ., - g+C SECTION 0-~-.... ·-:-·-stw--[" &C:AI.~t A ta!O .,. ----\·---JIIIIIIl) ltc>O ·----··~---· §ECTIQN E-E ~'A TYPICAL CHUTE WALL SECTION ~·e. ll200f 21!SO 2100 SECTION C·C ~•A SECTION B·B ~LatA GE~J<M. RI!.YJSION t . ' t ''". -·~· .. ._ ~-... - - ----- ~~~s--- GENERAL ARRANGEMENT ......-----'''So~ SCAI.X!A • 7 • • -- --· -- ADCC.O ~101'1 . • t -- SECTION A-A ~[18 CI21TE2fA ~IZ'IICC. l!PIU.~ ~· ~001:1 IIQ,.ClO t:.~ tM!.RG!JlCY !!.PIU.Wfo.V MAX~ n.«!!....;.-170.alol:.i': «:st~ ~ !AA'(I¥1,~ ~ h::Yt.,Oll-2ZOO' ~ll. IW>lllhiW u1~ 'Wim ~~-'I!~ - PLATE 7.4 WATAAA SCHEM£3A1 Pl~N ~ SECTlON --· - 1.'700 SPILLWAY PROFILE I 'fOCI -·-····~. ·---.... ··--·------ 1!!.00 SECTION A·A SECTION 8-8 .... , tq . ' • t • t • - - ----- 0 100 li)O F1tl' .... . . r 1 ...I I I I AlASKA. POWER AUTHOitTY ~tANA S~~AI . SPilLWAY , _ _....._,. ______ ..... ,.., __ ,.._. _...., ____ , ___ .,. ____ .,. _____ ,. ... A .. ·:,.;.-.. ~1"-----.......... , •• --- .. /-" .. ___ .. .--... ·~···~~::-\' ,...--··-···-----... --·· / _,.......,. -------- - 11100 1500 1400 1----------·-··----. -~----- ' ' ~~ I I ~A rt>B ---·•-. .... _ ... .__ ______ a..'ltG&' SPILLWAY CONTROL STRUCTURE (tHLAIZGI.O) SCAUl. t & u.n ~~----·---Coetl ·--·-------- SECTION A-A 1:1(; ... 1.1. • 0 ........... •• !.. .... ·~ ,. c~~l'lr'*l SPILLWAY PROFI,LJ;: -llc:AL£ I .a.. ............................... ""' ... l 1 I I ·--....... -... .. _____ _ •• --··-·--1 ,, __ I ' SECTION C·C 'SGA.Uio t & . ....... _____ ...,_....,._ .......... ~ ........ __ , ... ·-·-·-·-···-·--------,-...__,., ___ ... _____ .. ..., ______ _ -•• ---.. 0 --- ~-........... ..., N, ,f, q. -~---- ........ •• t ' . -· 1. ----Q -- • t . --- - PLATE 8.1 \VAT ANA VA~/£ M'£ ~'lAY ~llliltu.TM: ~t>lt.~ AAAANGEMENT -- 1900 t3qO '2,'2.00 tiOO tooo I 'tOO 1600 noo 1600 1500 I<&QO MAIN DAM -PROFILE .MAIN DAM SECTION AT MAXIMUM HEIG!iT I&Oor----------------------------b·~----------------------~--------------------------------------------------- • tcnn~ ta~YTR~ .. ,, . ~~':m. UPSTREAM COFFERDAM SECTION "'~~~'illT ' HOIIW.L ftNtlt ~~--~~~~~~~~~------------~-t--~~----~-r----~---\i~~--~~~ -~.M~I ~~ II.J' ,,~L_----~--~~~===Ll=====================~~~==~~====jljt======~~~-- • t • . I t 15 t •• <I\ ... ..,~ ... , ...... -........-, ........... _..,.._..,.__, ___ ,,._. __ _ --- - --,.,{)-- .... -. .,- PLATE S.2 l~TANA VALVE TYPE-SPillWAY AlTERNATN'E MI\IN 'Of\M /I.NO Cl\'£RSIOH f a • F'FFI--FI . ' -Cii* --· --. . ~.-.. . ~ . . . ~ - ' ·~ ~ 'f' • .. • • \. 4 ~ ~ • • ~ .. . . . . . . . " ~ ' . ·. ~ ~ . . .. ·~ ' . ... ... . . " . '· J;i<IO:... --- . -- -:-------·----,----- ---~-------'--·~·.- POWER FACILITIES -PROFILE ----· , ... , .• :J"f, ....... "-··~ ·----------,''l-!~·1>'~ ~ ---.. ··---·-·-·.. -·----------SPILLWi\v-:.-·pRoFiLE ________________ __..........__ ... ···-- ~ --------------.. -. ... ----. ~--.. ---~ -1------~~1<~~ -·---~----------------------- SERVICE SPILLWAY ______ ___,; __________ .. ,, ___ ::; ___ ~--~-~-~ .. :.; ... ~-~..-...:=-~-·····-----·-· -------------·. ·--·-·-··-·--·--·-·--------------------·-----------' ---·-------· ~----·--.. ,..,._..... ........... --. .....1!. --....... , . .,., ·- ----... ----· ---···-'-· -·-- •· ·* , ..... ~-·.:;-., ........... -... -· ' .. -·* ....... ~ ...... -·-.. " . ...-.--- ~ ~---=~~~-!.~"!!~"'~~~~~ -·-·-----~r~ WAtANA t.OOP.TlON CF' SHU-ll 2DNES -----·--·--- ·~!' -• t • 7 t • . , . ""·-"'-..... .. --.. -.-· ... .. .. ---·· -· ... ,......,._ ... _ _..,...... ........ ~,._ . .,. .... - ------~--. ~ ~~ -.. .-Q - ?-~ O·f' 1.111 i-9ll -.f.J;~ ~J·'l9 !}qtl ,.q:> r.n .... ~-~ , ... loot- •oa; ;~ 1 ..CIIi '!ll• .... ,$'lt) LATE 8·1 AlA$b.. POWER .l.UTHOiriY WATANA p.f\M VOLUMES rrrrrr ... " . --- I .I I I I .I I () I I WATANA DAM DESIGN I 1. General Considerations (W. Lamb) I I I I I I I. I I BORROW AREAS . 10-EET . • r~Q~TOURS 11. DATUM OF 1929 §\lA.':kA. • • • ~ . .... ~ .... :I Gil. SURVEY • 8 • OR RESTON. VIRGIN!.\ 22092 QiiAOr:ANGlE lOCATION S'(MOQLS IS AVAilABL£ Ott REQUEST •• WATANA 14t·3Q" 1Mapped, lconhol by ROAD CLASSIFICATION \Tnl"l<l'l~>'aonM N d . . !IC~l\cn o roa s or lta•ls m this area :UOIVCt5J1 TALKEETNA MOUNTAINS (0-4) . N6245-W14830/15X30 1951 .MUO!l!£YI$t011S 11165 po.ooo . ;1000 !zone 6 • ltanri Folios S·l - __, 0'1 I .....a '-0 co .....a 0 0 !) SUSITNA RNER • "2_,0~ nl/·1)3 T~'.AP·21 .~:--·-•• u.s, Slonjiord Sieve Optnlnga In lnc:hu f!j· un .. eo. . 70 -~ t1\ ; ~0 . I ~0 ·-J:: o-·-' ... . ~ ;II. 60 4;0 ,.. ..c. ~ . ..Q. "" & L.. 0 ~0 c: ·-U- II\ ~ ... 0 0 u -c:: -C) 40 (.) ... i$0 c :. ... u IU ; ... n. \ ... I D.. . . 30 '70 1 i \ ' ; ISO l J so tOO 0.0~ 0 100 '~0 .. 10 . 5 0.5 0.05 0,1 0.0~ 0.005 Gram Size in Millimeters . J I . . SAND, SILT or CLAY GRAVEL. Coar$0 I Fine I Coarse. J Medium Fine PI CLASSIFICATION 8 DESCRIPTION SM ~---------+~~~~~~-+------r.------r------r--------------------~--------------------~ Typical Gradation Curves ~~~~~--~,--~--~~---~--~---~-----t-------·1--------------------------------------------~ SM SM \ --. SM AH-02-4 SM AH-02-5 SM . AH-02-8 SM AH-02-9 SM . . DRAWN BY DL BORROW AREA D APPAOVSJ 61 j C 0 N SULTAN TS, IN C. SU~RY OF GRAIN SIZE DISTRIBUTIONS .DATE DEC. 198Y - - - - -.. ,c!!JI .. ) -ae --•e!!•· ... - - - - . . . . .. ' U,i.lf.N.1UJD iQVI Of'D.tNO 14 tiCifa'.S I . . . I ' f I 4 . I . • ' . r :. . . I. : • I • . . • • .. . I • • J • • . . . ··~ . ,• . • -t-i--+--1---10 H--H--t--1--l---lta t--t--1----liQ . . .•. ,,I I • I 1 . I if.nv~lqio Of JrDdjl~lpn· CUfVOS do~ived. frpm tests of samples from test pits. 8 t1uu 19 t Uorra\.t area D.. " (Outside lines represent extreme range of preliminary 1981 results} ! ... • l. I' ---.. --; --r -· .. -•-\-: .. _ -... • . . 00 40 )( ~ ·Z - 'I: 30 u -t-- U) ct ..J A. 20 10 7 4 0 BORROW AREA D ATTERBERG LIMITS FOR MATERIAL 0-10 FEET Natural Water Contents ® . --AH 10 AH = Auger Hole Results TP = Test Pits - ( ; . \~o 0 NP = Non Plastic samples #200 SIEVE ·® TP ."'I ) 40· 50 80 70· LIQUID ·LIMIT ., • :- 80 --·- 90 100 --- --- -.• -.. --·· -· -·--- - ~ z - BORROW AREA D ATTERBERG LIHITS FOR MATERIAL 10-20 FEET 10...-- Natural Water Contents #200 SIEVE eo..,.__ 40~--~~---~-----4-----4-----+-----+-----r~~~-----r----, 0 10 • . 40 60 60 LIQUID LIMIT 70 80 90 100 • -~-.. t --..... ·--·tal· ·-· ~ ---··-. -- .. ~ z - Natural Water Contents so ..... - 50.,___ BORROW AREA 0 ATTERBERG LIMITS FOR MATERIAL >20 FEET #200 SIEVE. 40~--~----~----4-----+---~-----t--~~~'-t-----r----t: ~~oL---~--~----4----4----+----~~--r-~~--~r---t 0 r.:: en cg ..J 0.. . 20L---~----~----4-----+--~~-----+~--~--~t-----r----. @ • f·.~~ ~., •. __ .J.. _ __,~-~~h.L...J..~~-+---+---t---;---r--; , " 1 00 60 70 80 90 100 LIQUID LIMIT I I I I I I I I .I I I I I ·~. I .. I I I I I . . ... R a M Consulbnt Inc. LABORATORY COMPACTION CQNT.RQ.. REFQ3T Jal) Nome ~ l.Dcafi"'"--..::.:.::z.&.a.MRL-.I..;:a.-...-...M:~~J~il.olo.li ..... ____ """"""=-'"-'--............ -,.....-~---~~--.--~--~-......... ~ Alchitect «Enginll4!' &ere• .-.rice z • Contractor • J A. Oalcripti~ of Soil: Vall Grad.C 'tttill'-GRAVELLY SILT! SAHD W '1'RJ.CE CLA . . Unifutd AASHO Mctwiol Merit-·------------ClassificotiOR _SM _____ Clas$fM:Otion . . Sautee o1 Material. Deadman cr.!ek ~l:!._~_w_-_ao-_J __ oo _ _...(_A_re_a_D __ ) -------~ Natuiol Wator Ccmnt 6 I" 0/o Natural ~ Density . PCF Speci fie: Gr04ity_ Uquid Limit l1otl Viscous 0/e Pt0$tic: Umit _____ •t. Plasticity lndex Non Pla.£tic ~ C. Tet Results: Maximum CNy Oensity_-.o:l::.:::l:;.;;;:S~·..:.O _____ PCF Optimum ~ater Content_..,g.,.~ 140 I 1\ Sieve Analysis \ \ 2 • lis • 1 10 3/4a l/2. Jta• t " f 10 140 1200 .02Jza .oos .oo:z 100 95 93 89 87 86 80 g 76 ... 58 g ! 26.9u 9-.2Q: 3.~ 135 130 125 . ·- ~ / 1/ "" / 1/ .I / f I J : -~ . . ~ ::, i ., !: .I :·. l ·: .. I i I -_\ /" ' / \ (1 ~ / - l_L~ \ \ \ :--:;,; ,.. ! -. lr.. I . I : I I . ·.• . ! ; . ' i ' ~·; I l_ I ~ . i \~ \ ~ " 1 "\ ... ' ' ';--\_ . I 1\.'~'~ i \"i \ iA . \ F.:' ft. l\ \ t \ t \9_ \ • \ ~- _'l ,, \ \ \ \ ' l ~ -\ \ \ ' I \ I •\ I \ I ' ! _! I \ I I \ I l \I I '4 I Range of natural water con~en t 10 15 0 c -·--·--~-.... --,~ ·-- ----£.··--~------·--·--·-------·--·------------~-----·---·----------··-·-----------t:l TP-80-19· \\:tentative) ~ " . AH-E9 8 I raoo·----··---- WATANA BORROW AREA E .. PREVIOUS EXPLORATIONS 21 TEST PITS FROM 1981 NOT SHOWN 0 TP-80-18 e Af-!-f:8 3.75' 0 TP-80-17 .+.cP focP "' 10ft -lliJtOC LDI. rltflW *)It~- I:DaiiJ ~L J i t-[.1.:./~ -1 Seismic Line . . • /111--7 . 0 TP-9 Auger Hole Test Pit ---:---; --' ' :.-· . . , .. ·~------- U.S. Standard Slt'tl Opening a In lnch.oo U.S. Sh'mdard Sieve Numben Htdromahr . 3 ~ 11/Z I 3/4 1/Z !/8 ! 4 6 B Jl f4 16 20 30 40 506070 too l.i\0 200 no 0 100 ~f\ I II • I I l r 1 \; ~ u. I I I I I II to. \. I' tC! 90 h. 10 r\ ...... ~ eo !\,. ~ 20 ~ "' 70 ~ i';;: 'lP E !21 1-1 SHALL0\•1 30 -"® -..:::: -(0-8 FEET) ;o. ..c. C\ \ ,•1() 'ii '3: ::: GO 40 '>. >-t-.1'-.;Q .0 ...... 'I'-·'CI ~ ...... tl 50 L-,. 50 ·~ c: t-=A. :t:J ·-t-....... lL 0 f... (0 .... ""'( ~ c DEEP SAMPLES -~ 40 60 ...:: u """'-. I ~ ,_ -. ·.0. ., r-... "- 0.. ..... ~ " ill.. 30 ~ 70 -.;;. ' . ~ ........ "'-.... 20 I .. 80 ~ • TP ~1 10 . E r-2 90 ' 0 too 100 ~0. 10 5 I 0.5 0.1 0.05 0.01 0.00~ 0.001 Grain Size in Millimeters . I GRAVEL I SAND I SILT or CLAY I Coarse I Fine I Coarse Medium Fine SAMPLE NO. MOISllJRE t;UNIENT OE~~ITY LL Pl CLASSlFICATlON a DESCRIPTION TP E21-1 SANDY SILT t'IITH TRACE CLAY TJ:l E21-2 Gt-1 SANDY GRAVEL \'lij'H ~nMF. SILT ' . ! . DRAWN BY R E L '} Engineering 8r Geological Consultants GRADATION CURVES FOR BORROW AREA E APPROVED BY MC H-- fVI ANCHORAGE FAIRBANKS ALASKA JUNEAU SUSITNA HYDROELECTRIC PROJECT DATE AU G. 1981 : PROJEcf NO. lJ5250'b TYPICAL GRADATION U.S. Standard Slave Openings In lnchn U.S. Slandard Sieve Numben Hydrometer 100 ~ 2 .L..l/Z I !14 112. ~/! '!! ' R ll ll 14 I 6 ~r 30 4( 50 60 7( 100 {41) 2 00 2.1 0 , ~ ~ ~ ~ ~ X' --. ~~ r--~ I I! I "'I.: .....;;;: ~ lh - 90 ' ' ~ ~" ~ ""-.. "'-.....; ~ "'l ~ "'-...! ~ ..... ~ ..... ... \ ~ ~ ~' ~ 11111111 Iiiii :--. ' ~ ~ ---..:::: ~;;;:::: 80 ' ~ ~ '"'~ :"'...... -I" ...... ~ t\\ ~ ~ ~ ~ ~~ ~~ ~ "'r-. ..... ill ~,.. ~ ~ ~ ~\ ,\\\ ~" :--..... ... ~~ ~· :'--,. ~tl.. -t--. ~ ~ l\" l\ \ \\~ ~-' r-... i\ ···-70 -.c ' ~~ ~" ~ \ ~ 1\\ \\\\ I' SHALLO~J SAHPLE RANGE 0\ 'Cij ?;: 60 >. .0 .... ., 50 c 1.1.. ' ~ ~ r--' r' ~ too. ~ ~\~ ~~ ~ ~ ~ ~ ~ ~ '-~ ~~ ~ ~ ~ ' ~ ~ ' '\:-., ' ~ ~ ~ ~ ~ \ -c ., 40 0 L. Cl) n. 30 ... ~ ~ ~ ~ ~ ~ ~ ) i"lll ~ ~ ~ ~ ~ ~ ~~ --.. ~ ~ ~ ~ 20 ~ 10 ~0 100 50 10 GRAVEL Coarse Fine SAMPLE NO. LL PI 1 Engineering a Geological Consultants II ANCHORAGE ·FAIRBANKS ALASKA JUNEAU '------------ """ \ ~\ \\\ i\ ~ r.. " ~\\\ " ~i '\ \ ' ~\\\ \ \ \. ~~ ~k--~ \ ~'\~ ~ ~~ ~ ~ \ \\\.\ ~\ ~~ t--o~ ~ ~ ~ \\ ,~""t\ ..... ~ ~F: ~~ ,, t' ~ " '-\ ~ ~ ~' ~ 0 ~ \ ~~' ~ ~~ ~~ ~ ~ ~~ ~~ ~ t\[\ :\. .. ~ '~ ~~ ~ ~ ~ ~ ...... ~ DEEP SAMPLE RANGE " """ ~ ~ ~~~ ~ .... ... ~~ ~ ...... Q ~ ~----...;;; ,s .... ~ ~ ~ 0~ ~· 0.0!1 0.00 O.OQ~ Groin Size In Millimeters SAND Medium Fine SILT or CLAY CLASSIFICATION a DESCRIPTION COMPOSITE GRADATION CURVES FOR BORROWN AREA E SUSITNA HYDROELECTRIC PROJECT 0 10 20 30 -cth •20 ~ -\0 :>. ..Q:l: """' <lti """ 50 ...... tn <0 •<.(;) -60 i.t:: '4b to ...... ~ ...... ~ 70 eo 90 100 0.001 •• ------•• ----.. - ~ .< . U. s. StonJkrd Slave Of lAing• In ln,hn U.S, ~Uondotd ta.ve N11mben Hydrometer . 3 2 11/2 t !1/4 liZ 3/0 -l 4 • 8 12._ _14 16 20 '10 "0 506070 100 l40 200 210 . 0 100 il ~ ' J II I I' I I I I I . I I I I I I II . ..... -. 90 ~ ~ ~ 10 ' ~ Ill --. "" . .... i . -~ ....... ' . 10 ~ ~Q . .. . .. ·~ "' ~r--.:--- ......... ~ . .. ~ ~ ~w~" ~,5~ . ~ ~ ' -70 . .. ~ ~ . '30 ..:.::: -" ~ ~ ..c ~ -01. -. .. i 3 }-2!:6-~ ~ .I' I"'' ~ ~ . ~r-~ :. 80 . . 1,~ "":---~ 4Q ::; . • '-Preliminary Limit of Gradation .}; . ~ R:--. '-. ' . ......_~ '-~~, . ·~ ... ' ,.,. ~ ~0 ill ~0 ---. . !'~ ~ ~ . :0 ... ·0 u.. .... Q -.. . N ~ ~ --- c -., 40 ~~ 6Q ,:;::: u '• -. -... ~ "'r-. " ., ~ h. -a. . ' t' '<:'II ' -. I ~ • a 30 ..... -1!1.. --70: ... . ' . -.....; ~ . ~ . .. •• i -=+ --~ --1'-: ~ _,_ . ao ~~~--6Q . ~ ~-----. ~ .... ~-~ ... .. -~ ...... ["'Il! . . .......... :--......_ ~ ~ ~0 . . '• . ., -~ 'I 90; . r--. , . --. - I tOO 0 too eao .. 10 ·~ I 0.6 . 0.1 0.0~ 0.01 0.005 0001 . . Groin Size in Millimeters \ 'G'RAVEL . I SAND \ ,, J . Coarse_ r Fine 1 c·oarse I Medium Fine SILT or CLAY . .. . . MOISTURE ORY . SAMPLE NO. !;ONlEt.!T. OENSlTY LL PI CLASSIFICATION a DESCRIPTION W-80-256 10.9 21.7 9.2 ---W-B0-257 12 .. 3 17. 1' 2.5 \ ' . -~ ' . . BORROW AREA H DRAWN BY DL R ¢M APPROVED B't J CONSUt..TANTS, lN C. SUV1MARY OF GRAIN SIZE DISTRIBUTION PATE DEC. 198JY -· OCftT UA_....._- I I I I I I l I I j . I J •• I ~ I I I I I I ' ·. r • R 8 M Consultant lnc. LABORATORY COMPACTION CONTROL REPORT Architect or Engineer Acres American Inc~. Contractor ~ · -----..--'"-----------------~ • Unified Material Mark_. __ c ____________ Classification GC-sc . AASHO . Classific.otioo Source of Material --Bo_r_r_o_w_Ar_e_a_· _H_._s_am __ p::...l._e_N_o_._w_-_a_o_-_2_5_6 __ --=----:-------1 . · Natural Water Content 10 .• 9 • 0/o Natural Ofy Density ______ PCF Specific Gravity_~ Liquid Umit __ 2_1_._7 ____ 0/o Plastic Umit_. _____ 0/o Plasticity Index.._. ---"'-"-"'---4 a Test Procedure Used __ · __ __._~~...J,;;I.S;;.J.J.~L..-.J..L_----.:;.AA~s~HT~O~------------~ C. Test Results.:Moxirnum Ory~Density_.1_3_9_·._o _______ PCF Optimum Water Content 6. 2 - \ Sieve Analysis ~ . f\ I Size % Passing \ i J I " ~" rf 4'' a~ 4 10 40 00 .02nun .005 .002 100 95 88 84 81 78 71 64 b 53 ~ 38 .. 2 0 140 24.3 ~ 135 13.6 (..) 0::: 8.6 w 0.. _. uj co -' >- }-u; ~ 130 0 >-a: 0 I . I I : I I I _.l T f I I l 1 !• I I ' ' _\_ I I .... \I ' t\ I \ l I i \ I ' l I J "'\ ·I r \ I b. J I i I C'\. J ~· j I \. I· l 'o I j II I ...... 1 ~ I \.1 ~'t 1 ! ~. ·v J l { I II l\. .. ..;; l II 1\..-\-.\. J I II "'\ ....., 1-b" j c s I <U ll ....., \ c l 0 ~ r u J1 ! I I I s.. \ I QJ \ I 4-' 1 I ttl I \ ! I I 3 • [\ 1 I 1 -! \ nl ~ ,s.. ! I_ ::::J ! \ I t ....., 1 ' I ~ z !\ ! • • . \ ! ~ .1 I I j \ t I I J 1\ - f I \ 5 10 f5 WATER CONT.ENT -PERCENT OF CRY WEIGHT ~--------------------------------------------------------------------------- I 1-, I I I I I I I I I I I I I I I I I· I I WATANA DAr~ SITE RIVER ALLUVIUt1 AVAILABLE Cx 10E CY) LOCATION DISTANCE TO AXIS FROM LONGEST HAUL -----~---,.._-...._ ... ______ .._ _______ .... ._.. ____________ ...,._,... ... __ ._..,. _____ _.._._. ...... _. ...... ~-- 1 2 3 5 E 7 . ----------...-------------------~-----------_, ____ .,.. _______ ~-------~ ..... UPSTREA~~ c 17 25+ 25+ 25+ 25+ 25+ DO~/NSTREA~1 0 0. 0 .31 47 79 TOTAL 0 17 25 8E 72 104 120 HIGH CONFIDENCE ESTir~ATE ON ABOVE QUANTITIES: UPSTREAM I) 7 14 14+ 14+ 14+ 14+ DOWNSTREPJ1 0 0 0 15 23 33 48 TOTAL 0 7 ±4 29 37+ L~7+ E2+ I I I I I I I I I I I. I I I I I I I I rJATANA DA~ EMBANKMENT QUANTITIES <xloE CY) <DEPENDENT ON FINAL LP,YOUT REFINEr~ENTS) TYFE OF MATERIAL REQUIRED EST AVAIL. SOURCE -------------------------------------------------~--------- I~1PERVIOUS FINE FILTERS · COARSE FILTERS ROCKFILL GRAVEL FILL CONCRETE Jl.GG I ROUGH TOTAL 10-15 5-6 . 1-2 55-60 71-83 ~1CY 50-75 AREA D 5-10+ AREA H 12.5 AREA E 1E AREA E 100+ QUARRY A 47-104 WITHIN 6 MILES OF . AXIS., IN RIVER. 10+ AREA E 2-5 TIMES REQUIREMENTS~ BASED ON PRELIMINARY TAKEOFFS. I I I I I I I I I I I I I I I I I . . .. . ' POSSIBLE WAYS. IN WHICH AN EARTHQUAKE MAY CAUSE FAILURE OF AN EARTH DAM ' . 1 -Disruption o~ dam by major fault movement in foundation~ . 2 -Loss of freeboard due to differential tectonic ground movements. 3-Slope ·failures· induced by ground motions. . . 4 -Loss of freeboard due to slope failure or soii compaction .. 5 -Sliding of dam on weak foundation materials. .. 6 -Piping failure through cracks induced b.y ground motions~ ... 7 -Overtopping of dam due to seiches in re ;~z--o~r. 8 -overtopping of dam due to slides or·r0ckfalls into reservoir. 9 -Failure of spillway or ou.tlet works. (Seed, 1979 -19th Rankine Lecture) \ l ) ----------------------------------------~------~--------------~-----------------~ .I •• I I I I •• I I I I I I I I I I I I DEFENSIVE MEASURES ·. . . J l -Al:low ample freeboard to allow for settlement, slumping or fault movements. 2 -Use wide transi~io.n zones of material not vulnerable to cracking • . 3 -Use chimney drains near the central portion of embankment • . 4 -Provide ample .drainage zones to allow for possible flow o£ ttla ter :through cz:acks •· · . 5 -Use wide core zones 6f plastic materials not vulnerable to cracking. 6 -Use a well-gr~ded filter upstream. of the core to serve as a crack stopper. , .. . 7 -Provide crest details which will prevent erosion in the event of overtopping_ 8 -Flare the embankment core lit abutment contacts. 9 Locate the core to minimize the degree of saturation of materials. "' 10 -S1;.abi1ize slopes around th,r-reservoir to prevent slides. • A • 11 -Provide special details if danger of fault movement in foundation. (Seed, 1979 -19th Rankine Lecture) l • I ;.-~ -~-~.:. • .. ..: .... •• 0 '_·'.:. •• ·_. • ••• .•• ~. •• :-•• ' • -• .r __ · .. ~ _.·. . . .. ;: •,. ' 7 . : ... · .. '. _.. :.··· .. ·· ~ : . ' .. _ ·~: .... · .. :.;·. ~ • "··~, ~ . . ·.' . '· . ' . --IIIII -··----IIIIi ------------~-------------~~ Aai1 l .·1~ \!..) ' ® ~1.900. ~ \ 0 ~ 200 400ft. ,-., ~ ' ~!!!J , and \~~ -lmpe~vious core from main b?rrow area. . ~.---\ ... and \.2f.:-J ·-Transition zone consisting· of well graded mixture of. silts,sand!2, gravels, cobbles and boulders to 15-inch maxirnwn.size. · ·: Shell zone of predominantly sands, gravels, cobbles and boulders to 24-inch maximum size. (£) Imperious core from selected abutment stripping. @·and @ Orainage zones consisting of grav,~ls, cobbles and boulders. . ' FIG. 112 MAXHIUM (}11lANKMEiiT SECTION--OROVIllE DA~ ®. ® @) ® .. .. . . . . Con ere te to.re block Seepage. meas'ute~n t ba~!tier Rip rap Grout curtain -~ · . . . f ''-----·--·----·--· ------·---·---------------____________ ......_ ___ , ___ ,. .... ,/ uao uoo • t\00 ' . •U3flt ·~ ~------~--~~--~,------l=~--~~~~~--------------------------------------~~~~~~--~~a.--~~---- 1100 ·~ I "!'CC ••oo I lOCO t<&oo \&00 1400 ~ ' _,-......., ...... ~ ...... , TIJA)IItL.S / , ,. ~~-----e_)(TE~.~r pf (;.(.DvT c vR~J JJ. ~lollli!IUol "' • ..J>d-: ~LM.l. LLUI't' T l 1 oour a 11!2' .. ..,.._.. ~~~, ! ............. . ~ IJ. ~~ ~· '/-\\ "'-..._ ,i-5'· . t"l . \ \.., ~ r.,. 11 L s-\ \r ~ -....... ... IIUPf!M>,~ ~ ...L:_ AOCI( ~~ n.1. .J.l ~ \ \ ROCI\ U&) ~ f'IU. "" ~ A.'TIA ---:/_j_ ,:;--\ \--~ """'"'" ............. FINL FlLTIA -J./tl.OIPE~ ~ 1 · \ ..\_--l'llfl. f'l1.:ru "-., LL I _l ' CALL~Y _ .. ~ l-.~ v.wt~1'. \ MAIN DAM SE~l\ION AT MAXIMUM HEIGHT ~ f,)~tfJI,I .qc..r=. t-toL~J ,.._ . -/~ .,_ ' ~r-----------------------~~--------------------------------------------------------------- • CCFI'\:"Doi.M l !IUMY 11UWI STitUC.'Tu~e • . ' . . '· UPSTREAM COFFERDAM SECTION #>') I C) 0 0 . - - - - - - - - - - - - ---.. -· . ' • l --~---- . . . .. . . 0 '. . . ' -· I I I I I I I I I I I I I I I I I I WATANA DAM DESIGN 2. Seismic Analysis (A. Burgess) • • • ··: •• .t; . . ... ~ . . . ·, .· • .~ '• • •r ',. :· ·_f • '; , I· . I •• I I I .I I I I I I I I . I I I I • I '· ~ A65 I A./S 7A7S /£.,/ T't h"eol"? Pw.? qeAr~l?oAJ {t.s. A-oss o~'='" ~IZ5NQ71:1) .(6 d) IS Fotert.A--poN 7)vzuv9 ::f?fiAKIN'Y ( ?JYN-+Nic. l.,~'"'"l CA:VSIIVC, ~7"/ZENC,TI-I ;s.x.c~ € Jer£) ., I I I I I t I I I I r J 1 Aa.. U .. 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THALW~G ,..,..;w MA.IOR BEDROCK OUTCROPS ;;, INFERRED LOCATION OF O?Z SHEAR ZONE KNOWN LOCATION OF SHEAR ZONE • PROBABLE RELICT CHANNEL ENTRANCES WATANA ---SPECIAL FEATURES I I I I I I I I· I I I I I I. I I I I I APPENDIX B REVIEW BOARD REPORT I ·~ I I I I • I I I I I I I I I I I I I SUSITNA HYDROELECTRIC PROJECT BOARD MEMBERS 1 S SUGGESTIONS AS A RESULT OF A MEETING WITH PROJECT GROUP HELD IN NIAGARA FALLS ON SEPTEMBER 8~ 1981 1 -GEOLOGY AND SEIS~1ICITY Board members believe that every effort should be made to expedite final logs of drill holes and drawings of geological plans and sections using old as well as new data. Early accomplishment of this will significantly aid the consideration of the fractured zone under the river at De vi 1 Canyon. The seismic ground motion for use in preliminary design should be defined in a manner which could be used in the license application: 2 -DAM DESIGN Design of the Watana earth-fill dam is not yet a definitive stage but slopes have been selected which would facilitate construction of diversion and anci 1- lary works. The adoption of these slopes in proposed ar-rangements should be reinforced by analysis or by a statement of precedents used in other dams of simi 1 ar materials and in simi 1 ar seismic terrain. Concern was expressed over the narrow width of filter zones at all elevations, and in particular nea,." the base where a poor transition at rock contact could lead to piping. The Board suggested that reference be made to the filter criteria in use in the James Bay structures. Board members suggested that grouting tunnels unde~ the dam can be shown on the drawings, but the probabi 1 i ty of main use is sti 11 an open question. Although the arch dam appeared to limit str·ess levels to satisfactory value during earthquakes up to 0.4 g with a damping factor of 10 percent, some board members felt that a more comprehensive examination was required of other para- meters such as in situ rock stresses in the abutma.nt. I I I I I I I: I I· I I I I I· I I •• 3 -RIVER DIVERStON, SPILLWAY AND OUTLET WORKS Board members thought that precedents for each element of design in the river diversion, spillway and outlet works should be clearly stated. The river diversion works at Watana appeared out of balance. The height of the upstream cofferdam was 140 feet and retained 125,000 acre feet of storage. The velocity of flow in the diversion tunnels was 50 ft/s, a high value. The econo- mic optimum arrangement presented exceeded precedents and should be reviewed with the object of reducing risks in.the event of the cofferdam overtopping. The merits of free flow tunnels should be considered more fully. The avoidance of nitrogen supersaturation downstream from the dams during spillage or release of water from the reservoir has dominated the design and stretched a precedent in a number of areas. In view of the design implications of these criteria, the Board be 1 i eves that every effort must be made to justify the need for these criteria. The use of 1 arge Howe 11 Bunger valves for spillway discharge requires trashracks upstream. The H.B. valves· would cause an inordinate amount of SJ6ray in the summer and ice in the winter and could be subject to vibration. A precedent fo.r Howell Bunger valves to be used for such duty had not been given. Neither had a precedent been given for a chute spillway with as 1 arge a drop and unit dis- charge. The use of a fuse plug in the emergency spillway creates risks of accident al failure with catastrophic release of water or no failure when neededo The Board pr.eferred a positive control of emergency releases by use of gates or similar structures. Board members stated that more consideration should be given to other types of low and intermediate level outlet works. The Board suggested that 11 break head orifices" could he used in these works as was done at Mica. The use of cascade spillways for service and auxiliary use should be considered in more detai 1 at Watana. :1 I •• . . I I I I I I I I I I I I I I I The structural adequacy of the sti llin_g basin at Devi 1 Canyon was questioned .. The fuse plug in the emergency spillway should, if possible, be replaced by a positive control • I an McCaig questi a ned the necessity of a diversion tunne 1 at Devil Canyon. No diversion tunnel was used at Kariba. In many cases, diversion is made initially through a channel and 1 ater through a port in the dam. 4 -INTAKE, POWERHOUSE AND TAILRACE TUNNELS The Board considered that the intake trashracks projecting above the water sur- face increases the probability of trashrack blockage by frazi·l ice. Reference should be made to the Churchill Falls design. The need for drawoff at various reservoir levels at Watana requires better definition. Definition might allow simp 1 ifi cation of the design. The location chosen for the underground powerhouse should be justified by rock quality, proximity to access and power lines, etc. Gates or stoplogs in the draft tube and tunnel outlet would, as shown, be sub- ject to freezing; some modification is needed. Successful operation of the facilities during construction, and in service after completion, requires that special attention be given to operating conditions and problems resulting from the vigorous winter climate in Alaska. 5 -CONSTRUCTION AND CONSTRUCTION MATERIALS At Watana, the tunnel outlets for diversion, tailrace and spillway are located -very close together. Cofferdam and penstock arrangements would be unduly com- plicated. The construction sequence should be considered in arriving at layout, particularly at Watana, since close location of structures can create problems for construction and for the operation of the facilities. Borrow pits for earth dam construction have been established and the suitability of grading determined. Exploratory work is currently underway on concrete aggregates and the resul.ts will soon be available. I I I I I I I I I I I I I I I I I I Same andesites are kno,wn to produce aggregates sub,iect to alkali-aggregate reaction. The properties of all potential concrete aggregates that would be used in the Devil Canyon and Watana dams and powerhouses should be established soon. cc: J. Lawrence J. G. Warnock A 11 Board Members J. MacPherson