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1 1 -65-1997 1 1 : 52AFt FROh1 SUBTERRA I t•JC <06 889 81 SE <br />1997 Annual Meeting Abstracts <br />(Alphabetical According to Lead Author) <br />(cont'd) <br />ESTIMATION OF ROCK MASS S7TtSN4TH AND <br />FOUNDATION SLIDING STABILITY ANALYSES, <br />MH.LTOWN HILL DAM, OREGON <br />Douglas D. Boyer <br />(con['d) <br /> <br />~, <br />cleystone intetbds ate ptesmt st come bush IIow <br />contacb. The clayuone interbeds are of volcanic origin <br />(ash) which have be® slightly metamorphosed a¢d range <br />m thidmeas flour 0.1 m -4 feet at the dam site. The <br />claystme interbeds dip downctreem at approximately !0 <br />degrees. Sutficial mapping of Irmited outcrops indicate <br />that predomina¢[ jointing at the dam site consists of <br />poorly developed, ¢eu vortical cooling joints and <br />subhorizonul flow conuds within the basalt <br />Sliding along continuous claysxone interbeds within the <br />foundation of the dam is considered to be the moA critical <br />mode of po[auial insubility io the foundatio¢. Two <br />major claystme inte[beds (g[ea[er than IO feet thick) hove <br />been identified below the proposed dam footprint. Two <br />dimensional limit oquilibritrm subUhy e¢alyses were <br />performed using the procedures omlinad by dte U.S. <br />Army Corps of Engineer. Malyses wee performed for <br />13 cross sections and "block" amlyses were performed for <br />selected areas o¢ each abutment The co¢figuntion of the <br />asstrmed failure sedate fot each cross section included <br />failure along the top of the claysWne intabed and shearing <br />through intau bedrock in the pascive portico of the block. <br />The shear strength of the bush rock mast was estimated <br />based on laboratory triaxial test results of inuct rock <br />sample and wing published cmmlatioas with know¢ or <br />estimated properties of the rock trrass. Aldtough rarely <br />used in geological e¢d geotechniul applintionc, the mud <br />to rock mass streagtlt carrelatioec have bees widely used <br />in rock mechanics analyses. 11LS emprncat approach <br />inwrporates the use of the Hoek-Brown bilure criteria in <br />wnjunuion with the rock more rating (RMR) cystem. <br />The results of the chbiliry a¢alyees ndiute that <br />minimum rewrrrmmded factors of safety were ma m <br />excesded for the loading co¢ditims rmalyad <br />The presmtatiw will focus on the proper cbaraderi7atim <br />of the si[e geology and Ute apptwch used in eotimatieg the <br />shear strength of the foundation materials. <br />Teke.H 1001( al:~Cir OL ~I!•J11fCr'OCtt <br />http://geoweb:tamu:edtiFaegl ".:::., `";.. <br />P1LOT TESTIlpG DEVELOPS DIIAL PHASE . <br />EXTRACiTON DESIGN REQUUtEMENTS AT A <br />SUPERPUND 31TE U!i VIRGINIA <br />L. Boyd BrKding, 111 %'owrrpork Drier, Kennesaw, (iA; <br />and Dbn Schre(bcr <br />A pilot tat was performed to develop requ¢emmts fm a <br />wmbined Groundwate Extraction and Vapor Extraction <br />(GFJVE) System at a Strperfimd Site in Virginia. The she <br />wu the forma lautia¢ of two co¢crete se¢ling ta¢kc <br />which were used fm dicposa( of wane water and <br />chlorinated solvents over a period of approximately 25 <br />ywrs. The waaera u¢ks leaked resulting in a dissolved <br />phase chlorinated solvent plume extending down gradie¢t <br />flour the origi¢al tank locrtiona. <br />A dml phase extraction test was then run for <br />approximatey 2 days ruirtg a gtotmdwster extradim rate <br />of 7.3 GPM a¢d a weli6ead wc[nffi of 1.4 inches of <br />mercury. the resuhing npor eaataaio¢ rate was <br />approximately 3 cundard cubic feet per minute. Mass <br />removal rates were meaateed by sampling the vapor <br />extractim and grouodwata discharge strums and <br />analyzing for the prrsmce of chlorinated organics. <br />At the cenfetence, law will ptecent the overll strategy to <br />treat the center of the plume with dual phase entracion <br />and idea to impl®mt an intrinsic remediation program to <br />addreu residual wrdaminatio¢. It will show tLe <br />methodology used to develop the design roquiremmts for <br />the 12•we11 dual phase extrctim and 6 well av injection <br />system which was installed at the site. It will discuss how <br />to design for cadenced grormdtwta yield in GENE <br />appliutio¢s. The pmsmOrtim will wmpare actual full <br />scale system pedotnrance with the pilot test results. <br />hfIIQE SUBSIDENCE AND ROCKFALL HAZARDS: <br />A CASE STIIDY FROM NORTHWEST COLORADO <br />Chris D. Breedr, PE, S¢bTerre, Inc.. Kirkland, WA; Rick <br />Ml1G, Cyprus TweM)+rnile Coal Comparry; and Jerry <br />Comvm~ C,r1.T,.+,•n FnoineMnglJd, Stroud, UK <br />Ibis papa addresses rocldall harards ttsuhing Icom <br />IongwaU imdetmitting of the Tweatytnile Cliff in <br />Northwest Cobrado. There have been numerous studies oC <br />rockfall htrLrds and engaroaiog masuros to control <br />rockfall haurds w the Rocky Mmmtains. Aowt:va, the <br />project i9 censidered to be reLtively rnique due primarily <br />to die anticipated see of boulder and the need to ptevmt <br />large bouWas from reachutg the ¢eatby Cotmty Road <br />The Foidel Creek Mme currmily eatrads coal using 800. <br />foot wide IottgswU pa¢els mined m 1,000.foot centers at <br />depths ranging from 800 to 900 feet below the top of the <br />Tweatymile Saadatma Ia May, 1994, ui area of the <br />Twrnrymile Sandstone cliff failed ova LongwaU Panel ti <br />in the western rnnri¢g district. This area is west of the <br />study area described in this papa and seat not considered <br />harardous due to the distance of the read from the cliff <br />and geaerUy favorable foreslope topography. However, <br />P. 2 <br />AEG `97 87 <br />