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Influence of stress level on the creep of unfilled rock joints
75A
An empirical model is developed that predicts accurately the transient response of salt creep to incremental and decremental changes in stress and temperature, k~ven though the model is empirical, it is derived from a firm theoretical framework for the micromechanical deformation processes of both steady-state and transient creep. In this model, the tr*.nsient creep functions modify the steady-state creep behavlour, which in t~rn is based upon creep mechanisms and the d~orm:~tion-mechanlsm m:Bp° The model is ~pplied successfully to experimental stress-drop results obtained for s:~it. Auth.
Time dependent behaviour 833095 T ~ Dk~FEhDENT ~TFRgl. PREsZ~IE,:~, ~OISSON'S RATIO .k'],i'U5URt~NT Tan TJ ong-Kie Proe lOth Interrmtionsl Conference on Soll 7echanics and Foundation Engineering~ Stockholm, 15-19 June 1981, V1, F797-800. Publ Rotterdam: A. A. Balkema, 1981 T~teral pressures have been measured as a function of time in a gauge oedometer under various stepwise loadir~s and it is recon~uended that to determine the initial and ultimate stress distribution that creep or relaxation tests are also carried out. The time dependent Poisson's ratio can then be determined. 833096 CREEP IN POLYCRYST}kLLINE AGGREGATES BY bW.TTF~ TRANSPORT THRO~K]H ~ LI(~U'ID PI{ASE RaJ, R J Geophys Res, ~ 7 , }~6, ]0 June 1982, I~7314739 Polycrystalline aggregates which contain some liquid in grain interfaces can deform by matter transport, through the liquid phase. If the applied stress is multlaxial, then the devlatorlc component of the stress will produce creep, that is, a change in shape of the aggregate without ar~ change in volume, while the mean stress will cause the aggregate to denslfy. Constitutive equations for creep rate and densificatlon rate are derived. I% is shown that the rate may be controlled either by the interface kinetics of dlssolution/preclpitatlon of the crystal from the liquid or by the diffusion rate of matter t~u'ough the liquid. The first process can be related to the kinetics of crystal growth from solution, and the second, to the viscosity of the liquid. The results of the ~nalysis ~re used to interpret experiments on densiflcation rate of a rock salt polycrystalline ~ggregate i~nersed in saturated brine. AL~hh.
833O97
TIT.~-DEPENDE~ ~_ VOL~rETR!C CON~f!TUTI~ RFLATION FOR FAULT GOUGE AhD CLAY AT HIGH PRESSURE Cht, C I; Wang, C Y Proc 23rd symposium on Rock ":echanics, Berkeley, 25-27 August 1982, P270-278. Publ N ~ York: A~.~, 1982 The time-dependent volumetric constitutive relation for a ~an Ar~Lreas fault gouge and a consolld~:ted k~olinlte ~re experiment~lly determined ~t confining pressUres to 200~nPa, under creep conditions ~r~ ~t ultrasonic frequency. At ~r~ given pressUre, the bulk modulus determined ~t l!~{z frequency is identical to the 'elastic' modulus determined at a stevwlse change of pressure. :fter the pressUre change~ there occurs a tlme-dependent change of volume and thus the effective bulk modulus. The constitutive relations may be modelled by a standard, linear, viscoel~stic medium with pressure-depart dent moduli and viscosity. Results imply that both stress and pOre pressUre in fnult zones may show t~,ne-dependent v~riations in response to a ch~.nge of st'~te of stress, such ~s thut occurring after ~n e~rthquake.
833o98 :,~'ORE KtRDENI_~}/REC~L=2y
MODEL OF TRANsIE~f CREEP OF ~ I T DURI}~. ~_~RESS LOADING A}~ U~Y_OADI~3 !4unson, D E; D~wson, P R Proc 23rd iymposium on Rock Mechanics, Be~'keley, 25-27 August 1982, ~299~306. Publ New York: : w'.~, 1982
833099
sTE zDY-/~ATE C R O P OF ROCK ;V.LT IN GEOFA~.INFERINO R~eifle, T W; 2ensezy, P E Proc 23rd Symposium on Rock "~echanlcs, Berkeley, 25-27 August 1982 , P307-314. Publ New York: AIT~, 1962 C~mpares 2 constitutive models proposed for the steady-state (secondary) creep of salt at certain stresses and temperat~es, and evaluates them using data from creep tests. Statistical (linear regression) ~r~lysis indicates that the simple model based on one defor~2tion mechanism does not represent the influence of stress ~nd temperature on the steady-state creep of salt. However~ the more complex, two-term model does not give as good predlct~ons of creep rates as the one-term model.
833100 Ir~LUENCE OF :~:T.~..S~ LEVEL ON THE CREEP OF UNFILLED ROCK J O l ~ q Schwartz, C 'J; Kolluru, .T Proc 23rd :-y~.poslum on Rock ~4echanics, Berkeley, 25-27 Au~xst 1982, P333-350. Publ New York: AI:~, 1982 Uni~xisl creep tests were performed on intact and Jointed s~mples of a specially farmulated gypsum plaster 'synthetic rock'. Results show that unfilled Joints increase the axi-cl creep displacements under unlaxlal compression. A simple thearetical asperity creep mechsnism is proposed to explain the observed behavlour. 833101 TRIAU
An empirical model is developed that predicts accurately the transient response of salt creep to incremental and decremental changes in stress and temperature, k~ven though the model is empirical, it is derived from a firm theoretical framework for the micromechanical deformation processes of both steady-state and transient creep. In this model, the tr*.nsient creep functions modify the steady-state creep behavlour, which in t~rn is based upon creep mechanisms and the d~orm:~tion-mechanlsm m:Bp° The model is ~pplied successfully to experimental stress-drop results obtained for s:~it. Auth.
Time dependent behaviour 833095 T ~ Dk~FEhDENT ~TFRgl. PREsZ~IE,:~, ~OISSON'S RATIO .k'],i'U5URt~NT Tan TJ ong-Kie Proe lOth Interrmtionsl Conference on Soll 7echanics and Foundation Engineering~ Stockholm, 15-19 June 1981, V1, F797-800. Publ Rotterdam: A. A. Balkema, 1981 T~teral pressures have been measured as a function of time in a gauge oedometer under various stepwise loadir~s and it is recon~uended that to determine the initial and ultimate stress distribution that creep or relaxation tests are also carried out. The time dependent Poisson's ratio can then be determined. 833096 CREEP IN POLYCRYST}kLLINE AGGREGATES BY bW.TTF~ TRANSPORT THRO~K]H ~ LI(~U'ID PI{ASE RaJ, R J Geophys Res, ~ 7 , }~6, ]0 June 1982, I~7314739 Polycrystalline aggregates which contain some liquid in grain interfaces can deform by matter transport, through the liquid phase. If the applied stress is multlaxial, then the devlatorlc component of the stress will produce creep, that is, a change in shape of the aggregate without ar~ change in volume, while the mean stress will cause the aggregate to denslfy. Constitutive equations for creep rate and densificatlon rate are derived. I% is shown that the rate may be controlled either by the interface kinetics of dlssolution/preclpitatlon of the crystal from the liquid or by the diffusion rate of matter t~u'ough the liquid. The first process can be related to the kinetics of crystal growth from solution, and the second, to the viscosity of the liquid. The results of the ~nalysis ~re used to interpret experiments on densiflcation rate of a rock salt polycrystalline ~ggregate i~nersed in saturated brine. AL~hh.
833O97
TIT.~-DEPENDE~ ~_ VOL~rETR!C CON~f!TUTI~ RFLATION FOR FAULT GOUGE AhD CLAY AT HIGH PRESSURE Cht, C I; Wang, C Y Proc 23rd symposium on Rock ":echanics, Berkeley, 25-27 August 1982, P270-278. Publ N ~ York: A~.~, 1982 The time-dependent volumetric constitutive relation for a ~an Ar~Lreas fault gouge and a consolld~:ted k~olinlte ~re experiment~lly determined ~t confining pressUres to 200~nPa, under creep conditions ~r~ ~t ultrasonic frequency. At ~r~ given pressUre, the bulk modulus determined ~t l!~{z frequency is identical to the 'elastic' modulus determined at a stevwlse change of pressure. :fter the pressUre change~ there occurs a tlme-dependent change of volume and thus the effective bulk modulus. The constitutive relations may be modelled by a standard, linear, viscoel~stic medium with pressure-depart dent moduli and viscosity. Results imply that both stress and pOre pressUre in fnult zones may show t~,ne-dependent v~riations in response to a ch~.nge of st'~te of stress, such ~s thut occurring after ~n e~rthquake.
833o98 :,~'ORE KtRDENI_~}/REC~L=2y
MODEL OF TRANsIE~f CREEP OF ~ I T DURI}~. ~_~RESS LOADING A}~ U~Y_OADI~3 !4unson, D E; D~wson, P R Proc 23rd iymposium on Rock Mechanics, Be~'keley, 25-27 August 1982, ~299~306. Publ New York: : w'.~, 1982
833099
sTE zDY-/~ATE C R O P OF ROCK ;V.LT IN GEOFA~.INFERINO R~eifle, T W; 2ensezy, P E Proc 23rd Symposium on Rock "~echanlcs, Berkeley, 25-27 August 1982 , P307-314. Publ New York: AIT~, 1962 C~mpares 2 constitutive models proposed for the steady-state (secondary) creep of salt at certain stresses and temperat~es, and evaluates them using data from creep tests. Statistical (linear regression) ~r~lysis indicates that the simple model based on one defor~2tion mechanism does not represent the influence of stress ~nd temperature on the steady-state creep of salt. However~ the more complex, two-term model does not give as good predlct~ons of creep rates as the one-term model.
833100 Ir~LUENCE OF :~:T.~..S~ LEVEL ON THE CREEP OF UNFILLED ROCK J O l ~ q Schwartz, C 'J; Kolluru, .T Proc 23rd :-y~.poslum on Rock ~4echanics, Berkeley, 25-27 Au~xst 1982, P333-350. Publ New York: AI:~, 1982 Uni~xisl creep tests were performed on intact and Jointed s~mples of a specially farmulated gypsum plaster 'synthetic rock'. Results show that unfilled Joints increase the axi-cl creep displacements under unlaxlal compression. A simple thearetical asperity creep mechsnism is proposed to explain the observed behavlour. 833101 TRIAU