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III III'lllll llll 111 ~ DOL•~A~••C•UK,~ZCtO/. `$ CXh,~iZJ
<br />•
<br />320 Mode/Studies of E((ecrs
<br />directly above or on the sides of the cavity. The Studies of the Influence of Stress, Temperature,
<br />gelatin had returned to its original condition of and Radiation on Flow and Stability in Rock
<br />little or no stress and the lines in the gelatin no Salt Mines." Proceedings oC the First Congress of
<br />longer showed any local deformation at points the International Society of Rock 1\lechanics,
<br />above the ~vax adjacent to the cavern boundary. October, 1966, Lisbon, Portugal.
<br />This vas also the case for the other models that
<br />V.H., "Role of Gravity in Orogenesis
<br />"
<br />Bucher
<br />shoved localized initial subsidence. ,
<br />,
<br />Bulletin of the Geological Society' of America
<br />The experiments using t.•ax to represent the salt 1965), v. 67, no. 10, p. 1295-1318.
<br />(October
<br />as a plastic medium suggest that if a cavity ,could ,
<br />eventually close, subsidence would occur kith a De~rillier, J.O., "Photoelastic and Grid Displace-
<br />varying pattern through time. One might expect a merit Anal}'sis of Gelatin Models ,.•ith Embank-
<br />period early in the history of closure in which max- merit Loads," X1.5. Thesis, Engineering
<br />imum subsidence would occur over the salt adja- l,lechanics Department, Louisiana State Univer-
<br />cen[ to the cavity rather than over the cavity, sity, June, 1965.
<br />itself. Ho,veccr, the final result long after cavity
<br />Dicis~on oC Engineering Laboratories, Bureau of
<br />closure begins would simph• be a small amount of Reclamation, Department of Interior, "Triaxial
<br />subsidence ort•r the entire sw'face of the sal[. The Compression Tests of Rock Salt Cores for the
<br />amount of [his Final subsidence „ill be relatively h'nited Slates Atomic Energy Commission-
<br />insignificant for cavity volumes in the 10,000,000 Project Dribble," Laboraton Report loo.
<br />to 15,000,000 cubic feet range. (-] 0~3), October, 1962.
<br />Experimental work demonstrates that iF the salt
<br />behaves as a brittle material, a ca,ity in the salt Jindal, V.I{., "\lodel Studies of the Effects of
<br />could collapse very rapidly'. The more cohesive cap Solution-Cavern Closure in Salt Domes," M.S.
<br />rock ,would then fracture in[ensivel}• and it would Thesis, Louisiana State Universit}, 1969.
<br />suffer local subsidence over the cavity. The over- "-accelerated Deformation of
<br />Lomenick, T.F.
<br />lying sediments ~.•ould also subside directly over ,
<br />Rock Salt at Elevated Temperature and Pressure
<br />the cavern although the magnitude of such subsid-
<br />and lts Implications for High Level Radioactive
<br />ence may be less than [hat in the cap rock or in the «`aste Disposal," Ph.D. Dissertation, University
<br />sal[. For sudden collapse of a cavity- located fairly oC Tennessee
<br />196S.
<br />close to the top of the salt, local subsidence can be ,
<br />expected immediately o,'er the cavity-. The failure Post, D., "Photoelasticity," Alanua! of Experi-
<br />of a cavity in the Choctaw Dome in Iberville ntert[a! SCress Anal}'sis, 2nd Edition, 1965, p.
<br />Parish, Louisiana probably represents this kind of 29.
<br />faiThe effect of cavity closure in a,iscoelastic me- Richards, R., and i`tark, R., "Gelatin Models for
<br />"
<br />dium is distinctive. As cavity- closure occurs in such Photoelastic Anal)•sis of Gravity Structures,
<br />a medium, the medium surrounding the cavern is Experimental 1\fechanics, January, 1966.
<br />stressed and an isochromatic pattern develops in Serata, S., and Gloy'na, E.F., "Principles of Struc-
<br />[he model around the cavity. The concentration of rural Stability of Underground Salt Cavities,"
<br />isochromatic lines increases „ith the closing of the Jot/rna! of Geophysical Research (September,
<br />cavity- showing an increase in the stress gradient 1960), v. 65, no. 9, p. 29 19.2987.
<br />around the cavity. Thus the stress gradient sur-
<br />R.L., and Arman, .~., "Qualitative Stress
<br />Thoms
<br />rounding the cavity increases t,ith closure if the ,
<br />Anal}•sis for Embankment Foundation," Report
<br />material has viscoelastic properties. on Loutsiana Department of Hight,ays Project
<br />REFERENCES i\o. 736.00-63, 1966.
<br />Bradsha,v, R.L., Lomenick, T.F., \1cClain, \V.C.,
<br />and Empson, F.l\1., "Alodcl and Underground
<br />
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