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Estimation of the experimental and basic components of the observed variance of rock strength
86A
Strength characteristics See also: 815245 8150~6 EFFECTS OF APP~RA~'JS SIZE AND SI~FACE ARF_A OF CHARGE ON THE IMPACT STRENGTH OF ROCK Rabia, H; Brook, N Int J ROCk Mech Min Scl, V18, N3, Jume 1 ~ i , P211- 219 Ftu~amen~al work into the effects of apparatus size on the impact strength of rock is reported. A series of tests using three sizes of a 'Protodyakonov' ~ p e drop hammer are carried out arzl the resultir~ values of impact h-urdness are cc~ed. The effects of size of charge on the impact h,~'dness of rock are investigated using crushed rock fragments. An empirical equation, contaiming impact hardness, Sh~re H~rdness and operating pressure ~s suggested for predicting the performance of percussive drills. Auth.
815o~i STATISTICAL PREDICTION FORMULA FOR COMPRESSIVE STRENGTH OF A ROCK Joag, A P; Lele, V S Rock Mech, VI3, N~, March 1981, P215-220 Develops ~ prediction formula for cor~essive stremgth of a rock in terms of its quality index (water absorbing capecity) and applies it to basalt and sandstone. 815048 EETIMATION OF THE EXPERD~NTAL AND BASIC COMPONENTS OF TKE OBSERVED V&RIA~CE OF ROCE" STRENGTH Pretorius, J P G Rock Mech, V13, N2, Nov 1~80, Pllg-130 The intercept of the strength correlelogram over distance is used to estimate the propor~,ions of the observed stremgth variance which can be attributed to the testing (experimental) procedure amd to the basic differences between the s t r e n g ~ of the specimens. The method is applied to saA~istone u~iaxi~l strength data (Wild, i ~ 8 ) where a l ~ o ~ m ~ t e l y half of the observed variance is ~ i m e n ~ a l and half basic. A spatial tre~i accounts for most of the basic variance. The u n i ~ i a l s t r e ~ is also spatially ccrre!ated with the triaxial stremgth. It is shown that the results of testing ;rocedures of equal reliability will be poorly correlated if the experimental components of variance are large. Auth. AND DRYING ON SHEAR STP~mNGTH 8150~9 EFFECT OF ~ N ~ Allam, M M; Srldhar~.n, A J Geotech Engng Div ASCE, V107, NGT~, A~ril 1981, I~21-437 Repca-ts lab tests of a silty sani in which specimens were subjected to up to 60 drying ani rewetting cycles amd then u ~ e r w e n t isotropica~ consolidated undrained tests in the conventions.l triax!~l shear apparatus. The tests showed increases in stiffness and brittleness, decrease in ccm;ressibllty and increase in shear stremgth as the intrinsic effective stress increases due to b o r i s generated by wettlmg and dry~mg.
815o~o EFFECT OF STRESS C O N C ~ I O N S
ON THE CYCLIC
BEHAVIOR OF SANDS Chancy, R C; Stevens, E; .Eheth, N Geotech Teat J, V3, N3, Sept 1980, P97-104
Describes cyclic t r i v i a l strength t.~sts, some on r~noulded sand specimens contairlng spherical inclusion of balls of cemented sanl, others on homogeneous specimens. Results indlcat.ed t h ~ the cyclic strergth ,'~fa specimen -~ith an inclusion ~¢as increased up to maximum of 6-7 per cent over th~.t of ~. corresponding homcgeneou~ specimen at ~n are~ ratio of I0 per cent. An increase in the area ratio to 25 per cent showed ~ decrease in cyclic str.~ngth to a level similar to th=t exhibited by n. homogeneous specimen. 8-!5051 UNIAXIAL STRENGTh{ O~ ROCK M~TF~IAL WiJk, G Geotech Test J, V3, N3, Sept 1980, PllS-119 Test~ to determine uni:~ximl tensile ~rAi compressive strength for a gr~nlte, a msrb].e and a sandstone are described. There was no statistically detectable difference betwe.~n the stremgth values of large a~i small s~mples, although the volume ratio of the samples was 20 or more. Sis-sin g~uge measurements ~aken during c ~ r e s s l o n tests on ~.e granite revmaled stremgth values iniepemdezfc of eccentricitie~ of sample lo~ds.
815o52 NOFMALIZED DYNAMIC U~DRAINED S~RENGTH OF SANDS SI/BJECTED TO CYCLIC AND RANDOM L O ~ L ~ D Tstsuoka, F; Yzs~is, S; Iwasaki, T Soils Found, V20, N3, Sept 1980, PI-16 Dezcribes undrained cyclic triaxlal tests on undisturbed sand. Analyses strer~-ths defined. by axial strain amplitudes ard developments of excess pore water. Presents a simplified equation for evaluating cyclic undrained triavial strer4[th of sani amd establishes a relations2~ip between strength for uniform cyclic loading amd for r~ndom cyclic loading. Proposes a simplified method for evaluating an equivalent uniform ].oading strength for a raniom loading using a strength curve obtained through uniform cyclic loading tests.
815053 ANISOTROFY OF THE UNDPAINED S T P ~ I ~ CONSOLIDATED CLAYS (IT ITAIXAN)
OF NO~JULLY
Cavalera, L; Scarpelli, O Riv Ital Geotec, V!4, h'3, July-Sept 1980,
P181-19o Presents a theoretical analysis of the unlrairmd shear stremgth :~risotropy fourzl in triaxisl shear tests, and compares this with observations on Fi~micino clays and other clays repel-ted in the literature. 815054 DRAINED RESIDUAL ~ T H . . OF COHESIVE SOIX~S Luplni, J F; Skinner, A E; Vaughan, P P Geotechnlque, V31, N2, June 1981, P181-213 Reviews correlation between residual friction ~ngle ~ni soil inie~ properties. Results of rin~ shear tests on different soil mixtures show that 3 types of residual behaviour occur depenii~g on the proportion of platy, low friction perticles and rotu~i I~A~ticles present. Considers the transition from one to the other in terms of particle packing. 6~ refa.
8z5o55 DIAMEVfRICAL C(~gPRE~ION OF TRANSVERSELY ISOTROPIC DISKS Warns, K A; Chores, K P Proc 21st US ~eympos~um on Rock Mecharlcs, Rol!a, Missouri, 28-30 May 1980, P2~3-248
Strength characteristics See also: 815245 8150~6 EFFECTS OF APP~RA~'JS SIZE AND SI~FACE ARF_A OF CHARGE ON THE IMPACT STRENGTH OF ROCK Rabia, H; Brook, N Int J ROCk Mech Min Scl, V18, N3, Jume 1 ~ i , P211- 219 Ftu~amen~al work into the effects of apparatus size on the impact strength of rock is reported. A series of tests using three sizes of a 'Protodyakonov' ~ p e drop hammer are carried out arzl the resultir~ values of impact h-urdness are cc~ed. The effects of size of charge on the impact h,~'dness of rock are investigated using crushed rock fragments. An empirical equation, contaiming impact hardness, Sh~re H~rdness and operating pressure ~s suggested for predicting the performance of percussive drills. Auth.
815o~i STATISTICAL PREDICTION FORMULA FOR COMPRESSIVE STRENGTH OF A ROCK Joag, A P; Lele, V S Rock Mech, VI3, N~, March 1981, P215-220 Develops ~ prediction formula for cor~essive stremgth of a rock in terms of its quality index (water absorbing capecity) and applies it to basalt and sandstone. 815048 EETIMATION OF THE EXPERD~NTAL AND BASIC COMPONENTS OF TKE OBSERVED V&RIA~CE OF ROCE" STRENGTH Pretorius, J P G Rock Mech, V13, N2, Nov 1~80, Pllg-130 The intercept of the strength correlelogram over distance is used to estimate the propor~,ions of the observed stremgth variance which can be attributed to the testing (experimental) procedure amd to the basic differences between the s t r e n g ~ of the specimens. The method is applied to saA~istone u~iaxi~l strength data (Wild, i ~ 8 ) where a l ~ o ~ m ~ t e l y half of the observed variance is ~ i m e n ~ a l and half basic. A spatial tre~i accounts for most of the basic variance. The u n i ~ i a l s t r e ~ is also spatially ccrre!ated with the triaxial stremgth. It is shown that the results of testing ;rocedures of equal reliability will be poorly correlated if the experimental components of variance are large. Auth. AND DRYING ON SHEAR STP~mNGTH 8150~9 EFFECT OF ~ N ~ Allam, M M; Srldhar~.n, A J Geotech Engng Div ASCE, V107, NGT~, A~ril 1981, I~21-437 Repca-ts lab tests of a silty sani in which specimens were subjected to up to 60 drying ani rewetting cycles amd then u ~ e r w e n t isotropica~ consolidated undrained tests in the conventions.l triax!~l shear apparatus. The tests showed increases in stiffness and brittleness, decrease in ccm;ressibllty and increase in shear stremgth as the intrinsic effective stress increases due to b o r i s generated by wettlmg and dry~mg.
815o~o EFFECT OF STRESS C O N C ~ I O N S
ON THE CYCLIC
BEHAVIOR OF SANDS Chancy, R C; Stevens, E; .Eheth, N Geotech Teat J, V3, N3, Sept 1980, P97-104
Describes cyclic t r i v i a l strength t.~sts, some on r~noulded sand specimens contairlng spherical inclusion of balls of cemented sanl, others on homogeneous specimens. Results indlcat.ed t h ~ the cyclic strergth ,'~fa specimen -~ith an inclusion ~¢as increased up to maximum of 6-7 per cent over th~.t of ~. corresponding homcgeneou~ specimen at ~n are~ ratio of I0 per cent. An increase in the area ratio to 25 per cent showed ~ decrease in cyclic str.~ngth to a level similar to th=t exhibited by n. homogeneous specimen. 8-!5051 UNIAXIAL STRENGTh{ O~ ROCK M~TF~IAL WiJk, G Geotech Test J, V3, N3, Sept 1980, PllS-119 Test~ to determine uni:~ximl tensile ~rAi compressive strength for a gr~nlte, a msrb].e and a sandstone are described. There was no statistically detectable difference betwe.~n the stremgth values of large a~i small s~mples, although the volume ratio of the samples was 20 or more. Sis-sin g~uge measurements ~aken during c ~ r e s s l o n tests on ~.e granite revmaled stremgth values iniepemdezfc of eccentricitie~ of sample lo~ds.
815o52 NOFMALIZED DYNAMIC U~DRAINED S~RENGTH OF SANDS SI/BJECTED TO CYCLIC AND RANDOM L O ~ L ~ D Tstsuoka, F; Yzs~is, S; Iwasaki, T Soils Found, V20, N3, Sept 1980, PI-16 Dezcribes undrained cyclic triaxlal tests on undisturbed sand. Analyses strer~-ths defined. by axial strain amplitudes ard developments of excess pore water. Presents a simplified equation for evaluating cyclic undrained triavial strer4[th of sani amd establishes a relations2~ip between strength for uniform cyclic loading amd for r~ndom cyclic loading. Proposes a simplified method for evaluating an equivalent uniform ].oading strength for a raniom loading using a strength curve obtained through uniform cyclic loading tests.
815053 ANISOTROFY OF THE UNDPAINED S T P ~ I ~ CONSOLIDATED CLAYS (IT ITAIXAN)
OF NO~JULLY
Cavalera, L; Scarpelli, O Riv Ital Geotec, V!4, h'3, July-Sept 1980,
P181-19o Presents a theoretical analysis of the unlrairmd shear stremgth :~risotropy fourzl in triaxisl shear tests, and compares this with observations on Fi~micino clays and other clays repel-ted in the literature. 815054 DRAINED RESIDUAL ~ T H . . OF COHESIVE SOIX~S Luplni, J F; Skinner, A E; Vaughan, P P Geotechnlque, V31, N2, June 1981, P181-213 Reviews correlation between residual friction ~ngle ~ni soil inie~ properties. Results of rin~ shear tests on different soil mixtures show that 3 types of residual behaviour occur depenii~g on the proportion of platy, low friction perticles and rotu~i I~A~ticles present. Considers the transition from one to the other in terms of particle packing. 6~ refa.
8z5o55 DIAMEVfRICAL C(~gPRE~ION OF TRANSVERSELY ISOTROPIC DISKS Warns, K A; Chores, K P Proc 21st US ~eympos~um on Rock Mecharlcs, Rol!a, Missouri, 28-30 May 1980, P2~3-248