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Temperature effects on strength and deformation behaviour of rocks in Southern Ontario
138A
In a 'continuous failure state' triaxial test the specimen is maintalned in the state of failure while subjected to steady changes of its state of stress. The specimen is brought to a state of failure at a chosen constant confining ~ressure. Then under monotonically increasing axial compression the confining ~ress~re is continuously adjusted so that a straight llne is ~ o d u c e d in the atress-atrain plane. Its slope is equal to that of the initially observed slope. It is shown that the stress path which the specimen is made to follow cc~'re~ponds closely to its failure envelope. Thus, it is possible~ in ~rinclple, to determine the failure envelope Of a rock with the aid of a sir~le test specimen. Over 120 tests on four dlffe~ent rock types have been carried out.
835o3o INFLUENCE OF WATER ON THE STRESS SUPPORTED BY EXPERIMENTALLY FAULTED WESTERLY GRA~A'±'~ Dennis, S M; Atklnson, B K Geephys J R Astr Soc, VT1, N2, Nov 1982,
m85-29~ Stress relaxation experime~s on l~e-faulted wet and dry Westerly granite are rep~ted. Results showed that at 300 deg C and 400 deg C, the wet samples required markedly lower shesr stresses for sliding than the dry samples. The deformation rate was a power function of the applied stress where the stress exponent was al~cximately 7 far pare water pressure of IOOMPa and 21 fcr pore water pressure of 20MPa. The experimental results were extrapolated to conditions believed to occur at depths of 10kin along the San Andreas Fault Zone. 835031 CORRELATION BETWEEN LOW-AMI~ITUDE SHEAR MCDULUS AND SHEAR STRE~YI~ FOR KAOLI~,'±'~ CLAY. TECHNICAL NOTE Athanasopoulos, G A; Richart, F E J Geotech Engng Div ASCE, Vl09, I~T~, May 1983, P719-723 Labaratcry tests were carried out on kaolinite clay to examine the effects Of average confinimg stress and overconsolidation ratio (0CR) on the ratio of iow-amplitnde shear modulus to shear strength. Resonant column tests arg consolidated umdralned trlaxial tests were perfcrmed. It is concluded that the ratio Of shear modulus to shear strergth is not a constant value, even far a single clay soil: variation Of the average effective confining stress ani OCR had a sigr~ficant effect. 835032 MULTIPLE FRACI~ING OF BOREHOLES BY USING TAILORED-PULSE LOADING Swift, R P; Kustlbov, A S SOC Pet Engr J, V22, N6, Dec i ~ 2 , P923-932 A laboratory experiment was developed to stray the effects of ~esst~izimg b ~ e h o l e s of rock samples ~ith tailored Imllses at intermediate loading rates. The experimerft focused on ascertaining the loadlmg conditions needed to ir~tiate multiple-fracture growth from a bc~ehole. Observations on samples of a medi%~n-pcrosity sandstone showed that the degree Of multiple fracturing is quite sensitive to the condition of the borehole as well as to the loading rate and appears strongly influenced by transient pare-pressure effects.
835o33 PROPOSED STANDARD TEST N~THOD FOR A FREE FALL PE NET~TION TEST Riggs, C 0 Geotech Test J, VS, N3-4, Sept-Dec 1962, P69-92
A standard test method for a free fall penetration test is proposed. It is stated within the new method that the apparatus can be used to satisfy the requirements of A~q~!~ Standard Method for Penetration Test and Split-Barrel Sampling of Soils (D 1586).
835o34 SHEAR STRENGTH OF THE ~qEATHERED CHAMPLAIN CLAY MEASURED IN A LARGE DIA!~TER TRIAYIAL TEST Lafleur, J; Lefebvre, G; ~arcotte, M Can Geotech J, Vlg, N4, Nov 1982, I~13-420 Describes the sampling procedure and the results of large diameter (150ma) consolidated isotropic drained (CID) triaxial tests on samples from the weathered (fissured) clay crust of the Champlain sea deposits. Eight compression tests under low confinlrg stresses were made: they showed that the post-peak strergth parameters were substantially higher than those back-calculated from a landslide occurring in the same weathered crust. Examination of the shape of the failure planes and of the stress-strain curves led to the conclusion that, in spite of the large sample size, the l~ropagatlon of fractures was controlled by the intact clay matrix rather than by the flssures. CID tests in the normally consolidated range were found to give results closer to the landslide back analysis results.
835035 MASs STRENGTH OF JOINTED RES!DU~I SOILS Koo, Y C Can Geotech J, V19, N3, Aug 1982, P225-231 The presence of low strength relict Joints in residual soils causes planes of weakness to f ~ . The strength distribution of Jointed soils is bimcdal, with the intact strength as an upper limit and the Joint strength as a lower limit: it varies with direction and the geometry of the potential sllp surface. A probabillstlc equation for estimating the mass strength of Jointed soils for slope stability analysis is ~resented, together with a case study as illustrat ion.
835036 T ~ T U R E
EFFECTS ON STRENGTH AND DEFORMATION BEHAVIOUR OF ROCKS IN S O U I ~ N ONTARIO Wal, R S C; Lo, K Y Can Geotech J, Vlg, N3, Aug 1982, P307-319
A labaratcry programme of loading tests to investigate the effects of elevated temperature up to 350 deg C on the strength ard d~formation behavlour of rocks was carried out. It was shown that the thermo-mechanlcal behavlour varies with rock type. For granitic gneiss, the deformation modulus increases slightly with temperature up to 120 deg C, then decreases at a rate of 25 per cent per 100 deg C. Poisson's ratio decreases with increasing temperature up to 250 deg C. The unlaxial compressive strength decreases with increasing temperature at a rate of aPl~aximately 30MPa per lO0 deg C. In contrast, the deformation and strength behavlour of limestone appears to be insensitive to temperature change.
835037 CYCLIC STRET~TH AND DEFORMATION OF NORMALLY CONSOLIDATED CLAY Yasuhara, K; Yamanouchi, T; Hirao, K Soils Fotznd, V22, N3, Sept 1982, P77-91 Repeated triaxlal compression tests on a saturated marine clay were analysed in terms of both the effective stress and the total stress. Important factgrs found to influence the strergth and deformation characteristics of the clay a@e the loading frequency, the stress induced anlsotropy, and the drainage condition.
In a 'continuous failure state' triaxial test the specimen is maintalned in the state of failure while subjected to steady changes of its state of stress. The specimen is brought to a state of failure at a chosen constant confining ~ressure. Then under monotonically increasing axial compression the confining ~ress~re is continuously adjusted so that a straight llne is ~ o d u c e d in the atress-atrain plane. Its slope is equal to that of the initially observed slope. It is shown that the stress path which the specimen is made to follow cc~'re~ponds closely to its failure envelope. Thus, it is possible~ in ~rinclple, to determine the failure envelope Of a rock with the aid of a sir~le test specimen. Over 120 tests on four dlffe~ent rock types have been carried out.
835o3o INFLUENCE OF WATER ON THE STRESS SUPPORTED BY EXPERIMENTALLY FAULTED WESTERLY GRA~A'±'~ Dennis, S M; Atklnson, B K Geephys J R Astr Soc, VT1, N2, Nov 1982,
m85-29~ Stress relaxation experime~s on l~e-faulted wet and dry Westerly granite are rep~ted. Results showed that at 300 deg C and 400 deg C, the wet samples required markedly lower shesr stresses for sliding than the dry samples. The deformation rate was a power function of the applied stress where the stress exponent was al~cximately 7 far pare water pressure of IOOMPa and 21 fcr pore water pressure of 20MPa. The experimental results were extrapolated to conditions believed to occur at depths of 10kin along the San Andreas Fault Zone. 835031 CORRELATION BETWEEN LOW-AMI~ITUDE SHEAR MCDULUS AND SHEAR STRE~YI~ FOR KAOLI~,'±'~ CLAY. TECHNICAL NOTE Athanasopoulos, G A; Richart, F E J Geotech Engng Div ASCE, Vl09, I~T~, May 1983, P719-723 Labaratcry tests were carried out on kaolinite clay to examine the effects Of average confinimg stress and overconsolidation ratio (0CR) on the ratio of iow-amplitnde shear modulus to shear strength. Resonant column tests arg consolidated umdralned trlaxial tests were perfcrmed. It is concluded that the ratio Of shear modulus to shear strergth is not a constant value, even far a single clay soil: variation Of the average effective confining stress ani OCR had a sigr~ficant effect. 835032 MULTIPLE FRACI~ING OF BOREHOLES BY USING TAILORED-PULSE LOADING Swift, R P; Kustlbov, A S SOC Pet Engr J, V22, N6, Dec i ~ 2 , P923-932 A laboratory experiment was developed to stray the effects of ~esst~izimg b ~ e h o l e s of rock samples ~ith tailored Imllses at intermediate loading rates. The experimerft focused on ascertaining the loadlmg conditions needed to ir~tiate multiple-fracture growth from a bc~ehole. Observations on samples of a medi%~n-pcrosity sandstone showed that the degree Of multiple fracturing is quite sensitive to the condition of the borehole as well as to the loading rate and appears strongly influenced by transient pare-pressure effects.
835o33 PROPOSED STANDARD TEST N~THOD FOR A FREE FALL PE NET~TION TEST Riggs, C 0 Geotech Test J, VS, N3-4, Sept-Dec 1962, P69-92
A standard test method for a free fall penetration test is proposed. It is stated within the new method that the apparatus can be used to satisfy the requirements of A~q~!~ Standard Method for Penetration Test and Split-Barrel Sampling of Soils (D 1586).
835o34 SHEAR STRENGTH OF THE ~qEATHERED CHAMPLAIN CLAY MEASURED IN A LARGE DIA!~TER TRIAYIAL TEST Lafleur, J; Lefebvre, G; ~arcotte, M Can Geotech J, Vlg, N4, Nov 1982, I~13-420 Describes the sampling procedure and the results of large diameter (150ma) consolidated isotropic drained (CID) triaxial tests on samples from the weathered (fissured) clay crust of the Champlain sea deposits. Eight compression tests under low confinlrg stresses were made: they showed that the post-peak strergth parameters were substantially higher than those back-calculated from a landslide occurring in the same weathered crust. Examination of the shape of the failure planes and of the stress-strain curves led to the conclusion that, in spite of the large sample size, the l~ropagatlon of fractures was controlled by the intact clay matrix rather than by the flssures. CID tests in the normally consolidated range were found to give results closer to the landslide back analysis results.
835035 MASs STRENGTH OF JOINTED RES!DU~I SOILS Koo, Y C Can Geotech J, V19, N3, Aug 1982, P225-231 The presence of low strength relict Joints in residual soils causes planes of weakness to f ~ . The strength distribution of Jointed soils is bimcdal, with the intact strength as an upper limit and the Joint strength as a lower limit: it varies with direction and the geometry of the potential sllp surface. A probabillstlc equation for estimating the mass strength of Jointed soils for slope stability analysis is ~resented, together with a case study as illustrat ion.
835036 T ~ T U R E
EFFECTS ON STRENGTH AND DEFORMATION BEHAVIOUR OF ROCKS IN S O U I ~ N ONTARIO Wal, R S C; Lo, K Y Can Geotech J, Vlg, N3, Aug 1982, P307-319
A labaratcry programme of loading tests to investigate the effects of elevated temperature up to 350 deg C on the strength ard d~formation behavlour of rocks was carried out. It was shown that the thermo-mechanlcal behavlour varies with rock type. For granitic gneiss, the deformation modulus increases slightly with temperature up to 120 deg C, then decreases at a rate of 25 per cent per 100 deg C. Poisson's ratio decreases with increasing temperature up to 250 deg C. The unlaxial compressive strength decreases with increasing temperature at a rate of aPl~aximately 30MPa per lO0 deg C. In contrast, the deformation and strength behavlour of limestone appears to be insensitive to temperature change.
835037 CYCLIC STRET~TH AND DEFORMATION OF NORMALLY CONSOLIDATED CLAY Yasuhara, K; Yamanouchi, T; Hirao, K Soils Fotznd, V22, N3, Sept 1982, P77-91 Repeated triaxlal compression tests on a saturated marine clay were analysed in terms of both the effective stress and the total stress. Important factgrs found to influence the strergth and deformation characteristics of the clay a@e the loading frequency, the stress induced anlsotropy, and the drainage condition.