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Deformability of layered or jointed rock masses: Analysis and comparison of different types of test
128A
826025 CONE PENETROMETER AND LIQUID LIMIT. TECHNICAL NOTE Wood, D M Geotechnique, V32, N2, June 1982, P152-157 Discusses the use of a cone penetrometer to measure the liquid limit of soils and compares the method with the Casagrande method and the results with the undrained strengths of clays. Concludes that the method provides a useful index property for soils. 826026 SPATIAL VARIABILITY OF THE UNDRAINED ~IRENGTH OF CLAYS Asaoka, A; A-Grivas, D J Geotech Engng Div ASCE, Vl08, NGTS, May 1982, P743-756 A simple yet accurate procedure for the description of the spatial variability of the undrained shear strength S of soft clays is achieved on the basis of experimental findings and field observations of the depth-dependent nature of S. The main features of the method are a linear with depth variation of the mean value and standard deviation of S and a smooth exponential function that describes the correlation between values received by S at different vertical locations. The developed procedure is illustrated in a case study involving actual strength data. 826027 OFFSHORE SAMPLE DISTURBANCE AND ITS EFFECT ON PILING DESIGN Dov._-r~ A R; Ralney, W S; Thompson, G R Oil Gas J, v79, N41. 12 Oct 1981, I~7-90 MinlsZure vane tests and fall cone tests were carried out on samples of marine clay. Undrained ~hear strengths obtained from these methods are compared. It was also found that testing location within the samples affected the streng~Ja results, wi¢/~ undrained shear streng*~h values obtained from tests conducted near the tip of the sampling tubes being consistently lower than at selected points further into the tube. The effect of these different .values on ~ltlmste pile capacity and p~le design is shown. 826028 STUDY ON BIAXIAL TESTS OF ROCKS. MECHANICAl. BEHAVIOUR OF ROCK PLATE SPECIMENS UNDER COMBINED STRESSES OF COM~RESSION-COMPRESSION AND COMPRESSION-TENSION (IN JAPANESE) Kobayashi, R; Furuzumi, M J Min Metal/ Inst Japan, V97, Nlll6, 1981-1982, I~77-82 Biaxial tests were carried o~b on Ogino tuff, Karawago tuff and Kimachi sandstone using a specially designed machine. Th~ msximum value of fail1~re strength of Kawarago tuff in compression-compression test is about 1.4 times the unlaxial compressive strength, Kimachl sandstone about 1. 9 times, and Ogino tuff about 1.3 times. The increase of failure strength of rocks in compresslon-compresslon tests shows that the magnitude of the intermediate principle stress has a considerable influence on the magnitude of the fracture strength. The failure limiting llne of rocks in compressiontension test has two sections~ One curved section shows the range over which the failure strength of rocks decreases as the tensile stress increases. The other linear section shows the range over which the failure strength g~adua/_ly spproaches the uni~xisl tensile strength.
826029 STRENGTH OF ROCK MASS ESTIMATED BY TESTING M~OD OF sHEARING ROCKS Bk~/WEEN TWO BOREHOLES (IN JAPANESE ) Kobay~shi~ R; S ~ o t o , F J Min Metal/ lr~st Japan, V97, Nlll5, Jan 1981, FT-12 A new b~rehole-type shear instrument is inserted in one side of the two bore-holes and the rocks between the bore_holes are punched by s shear edge which is pressed by an oil p~mp. The shear strength Is calcul=_ted from the applied shear los~ and the shearing area° 826030 API~LICATION OF A CRITICAL STATE SOIL MODEL FOR CYCLIC TRIAXIAL TESTS Carter, J P; Brooker, J R; Wroth, C P Proc 3rd Australia-New Zealand Conference on Geomechanics, Wellington, 12-16 May 1980, V2, P121-126. Publ Wellington: New Zealand Institution of Engineers, 1980 The concepts of critical state soll mechanics have been used to develop a simple mathematicsl model which predicts many aspects of the beh~vlour of clays under repeated loading. The model employs the parameters that are usually associated with the Cam-clay family of models together with an additional parameter which chsracterises the cyclic behaviour. Numerical studies are made of the behaviou~ of the model urder cyclic triaxial test conlitlons. Predict i o ~ are compared with the results of laboratory tests on a saturated clay. Auth. 826031 RATIONAL APPROACH TO THE POINT LOAD TEST Read, J R L; Thornton, P N; Regan, w M Proc 3rd Australla-New Zealand Conference on Geomechanlcs, Wellington, 12-16 May 1980, V2, P35-39. Publ Wellington: New Zealand Institution of Engineers, 1980 Conversion factors correlating point load strength with unlaxial compressive strength are subject to errors. In additlon test results may be ~ffected by sample anisotropy. Examples are given to show that provided these limitations are recognised the test can be successfully used to measure the strength of rock samples and classify rock. Auth. 826032 SOME PLASTICTTY SOLUTIONS RELEVANT TO THE BEARING CAPACITY OF ROCK AND FISSURED CLAY. JOHN JAEGER MEMORIAL LECTURE Davis, E H Proc 3rd Australla-New Zealand Conference on Geomechanlcs, Wellington, 12-16 May 1980, V3, P27-36. Publ Wellington: New Zealand Institution of Engineers, 1980 Examines the theoretical effects of seml-brittle or strain softening behaviour and the presence of defects, such as Joints and fissures, on the stability of soil and rock masses. This is done by analysing results from box models to determine the surface bearing capacity under plane strain conditions and under mouotonically increasing or single load application. Cyclic loading of footings is briefly considered 0
Deformation characteristics 826033 DEFORMABILI'Iqf OF LAYERED OR JOINTED ROCK MASSES: ANALYSIS AND CC~PARISON OF DIFFERENT TYPEs OF TEA
129A
Bayly, B; Cousens, E Int J Rock Mech Min Sci, VI9, ~ , P195-199
Aug 1982,
Tests using a borehole Jack or a pressure plate on tunnel wall are unsuitable for layered or Jointed rock masses. Such rock masses possess five deformability measures (2 Youngts moduli, 2 Poisson's ratios and the sheer modulus) stud the procedures mentioned, which were developed for measuring just two parameters, are not adaptable. Jack tests on in situ blocks that have been partly isolated by saw-cuts are more suitable, perhaps in conjunction with seismic methods.
826034 S(~4E ELemeNTS
OF A THEORY FOR IN-SITU S~I~ESS. TECHNICAL NOTE McCutchenj W R Int J Rock Mech Min Sci, vIg, ~ , Aug 1982s P201-203 Presents the elements of an in situ stress theory which accounts for the anc~sl@~s behaviour of K (the ratio of average horizontal stress to vertical stress): K being greater than 1 at shallow depths but becoming less than 1 at great depths, eventually reaching a constant value° The method is applied to a model of a self-gravitating spherical shell situated on an unyielding, massive, interior body. The resulting stress- strsin relations are then applied to observed data in the earth's crust.
826035 P R E S ~ TEST IN A HOMOGENEOUS LINEARLY ElAsTIC CROSS-ANISOTROPIC SOILo TECHNICAL NOTE Warren, S J Geotechnique, V32, N2, June 1982, P157-159 Gives an analysis showing that in a cross-anisotropic soil the pressur~neter test yields values of the horlzontal-to-horizontal sheer modulus, which can be used in predicting deformations.
826o36
CONSEQUENCES OF DEVIATORIC NORMALITY IN PLASTICITY WITH ISOTROPIC STRAIN HARDENING. SHORT COMMUNICATION Baker, R; Desal, C S; Int J Num Anal Meth Geomech, V6, N3, July-Sept 1982, P383-390 For mar~ soils experimental evidence suggests that deviation from nc~mallty between the plastic strain increments and the yield function is exhibited mainly in the voltametric behavlour, whereas the deviatoric behavio~r e~xhibits ne~nnality. An analysis of the consequence of this observation is presented, and it leads to an expression for the plastic potential function as composed of two functions: a yield function and another depenlent only on the hydrostatic l~'e ssl/re.
826037 RESILIENT CHARACTERISTICS OF BRAZILIAN SOILS de Medina, J; Preussler, E S J Geotech Engng Div ASCE, V108, NGTS, May
1982, P697-712 Resilient properties of twenty soil samples from subgrades, sub-bases, and mechanically stabilised soil bases of flexible pavements in the South and Southeast of Brazil were evaluated. Soils are mostly residual in origin. Correlations of resilient moduli with confining pressure or deviator stress were established. Co~relations of resilient moduS/ with CBR values were established for finp~Irained soll samples.
A tentative soil classification according to resiliency is developed. Also reference Is made to the applications to pavement deflection calculstions. Auth. 826038 ELASTIC AND PLASTIC STRAIN PROPERTIES OF SAND. TECHNICAL NOTE Ting, C S J Geotech Engng Div ASCE, VI08, NGTS, May 1982, P787-793 Reports measurements of the elastic and plastic volumetric and axial strains of samples of medium sand with 2 different unit weights. The tests were carried out in s. conventional triaxial apparatus with loading and unloading, under conditions of hydrostatic and deviator stress, up to a maximu~n hydrostatic stress of 4 k ~ s q cm. 826039 ELASTIC BEHAVIOUR OF NORMALLY CONSOLIDATED CLAY Ohmaki, S Proc 3rd Australia-New Zealand Conference on Geomeehanics, Wellington, 12-16 May 1980, V2, P127-132. Publ Wellington: New Zealand Institution of Engineers, 1980 In this paper the elastic strain of soil is assumed to consist of two components: one caused by changes in stress ratio and the other by changes in meaneffective stress. These 2 components were studied by conducting triaxial drained tests with various stress paths on samples of consolidated clay. Based uponthese results, an empirical law for stress-straln behaviour under axisymmetric conditions is proposed. 826040 AUTOMATIC JOINT EI]~MENT GENERATION TO SIMULATE STRAIN SOFTENING YIELD BEHAVIOUR IN EARTHEN MATERIALS Richards, B G Proc 3rd Australla-New Zealand Conference on Geemechanics, Wellington, 12-16 May 1980, V2, P233-239o Publ Wellington: New Zealand Institution of Engineers, 1980 This paper describes a model incorporating automatlcally generated joint elements to simulate the observed behaviour of strain softening materials, including the post-yield behaviour. Good agreement was obtained when this model was used to back analyse triaxial and direct shear tests of such material. The collapse load of strip footings as predicted by this model was also compared with previously published results, giving excellent agreement.
Surface properties 8260~1 CERCHAR AHRASIVITY INDEX AND ITS RELATION TO ROCK MINERALOGY AND PETROGRAPHY Sua~as M; Petersj T Rock Mech, VIS, NI, June 1982, PI-8 To evaluate the relation between the Cerchar Abrasivity Index (a parameter used in calculating advance rates of full face turmelling machines) and the petrography of the rocks, measuremerits were made on minerals and monemineralic rocks. From these data a thearetical abrasivity (quartz equivalence) can be calculated for every rock c~nposition. From the comparison of the theoretical and experimentally determined abrasivity the influence of fabric and other factors besides mineralogical composition were deduced. A u t h .
826025 CONE PENETROMETER AND LIQUID LIMIT. TECHNICAL NOTE Wood, D M Geotechnique, V32, N2, June 1982, P152-157 Discusses the use of a cone penetrometer to measure the liquid limit of soils and compares the method with the Casagrande method and the results with the undrained strengths of clays. Concludes that the method provides a useful index property for soils. 826026 SPATIAL VARIABILITY OF THE UNDRAINED ~IRENGTH OF CLAYS Asaoka, A; A-Grivas, D J Geotech Engng Div ASCE, Vl08, NGTS, May 1982, P743-756 A simple yet accurate procedure for the description of the spatial variability of the undrained shear strength S of soft clays is achieved on the basis of experimental findings and field observations of the depth-dependent nature of S. The main features of the method are a linear with depth variation of the mean value and standard deviation of S and a smooth exponential function that describes the correlation between values received by S at different vertical locations. The developed procedure is illustrated in a case study involving actual strength data. 826027 OFFSHORE SAMPLE DISTURBANCE AND ITS EFFECT ON PILING DESIGN Dov._-r~ A R; Ralney, W S; Thompson, G R Oil Gas J, v79, N41. 12 Oct 1981, I~7-90 MinlsZure vane tests and fall cone tests were carried out on samples of marine clay. Undrained ~hear strengths obtained from these methods are compared. It was also found that testing location within the samples affected the streng~Ja results, wi¢/~ undrained shear streng*~h values obtained from tests conducted near the tip of the sampling tubes being consistently lower than at selected points further into the tube. The effect of these different .values on ~ltlmste pile capacity and p~le design is shown. 826028 STUDY ON BIAXIAL TESTS OF ROCKS. MECHANICAl. BEHAVIOUR OF ROCK PLATE SPECIMENS UNDER COMBINED STRESSES OF COM~RESSION-COMPRESSION AND COMPRESSION-TENSION (IN JAPANESE) Kobayashi, R; Furuzumi, M J Min Metal/ Inst Japan, V97, Nlll6, 1981-1982, I~77-82 Biaxial tests were carried o~b on Ogino tuff, Karawago tuff and Kimachi sandstone using a specially designed machine. Th~ msximum value of fail1~re strength of Kawarago tuff in compression-compression test is about 1.4 times the unlaxial compressive strength, Kimachl sandstone about 1. 9 times, and Ogino tuff about 1.3 times. The increase of failure strength of rocks in compresslon-compresslon tests shows that the magnitude of the intermediate principle stress has a considerable influence on the magnitude of the fracture strength. The failure limiting llne of rocks in compressiontension test has two sections~ One curved section shows the range over which the failure strength of rocks decreases as the tensile stress increases. The other linear section shows the range over which the failure strength g~adua/_ly spproaches the uni~xisl tensile strength.
826029 STRENGTH OF ROCK MASS ESTIMATED BY TESTING M~OD OF sHEARING ROCKS Bk~/WEEN TWO BOREHOLES (IN JAPANESE ) Kobay~shi~ R; S ~ o t o , F J Min Metal/ lr~st Japan, V97, Nlll5, Jan 1981, FT-12 A new b~rehole-type shear instrument is inserted in one side of the two bore-holes and the rocks between the bore_holes are punched by s shear edge which is pressed by an oil p~mp. The shear strength Is calcul=_ted from the applied shear los~ and the shearing area° 826030 API~LICATION OF A CRITICAL STATE SOIL MODEL FOR CYCLIC TRIAXIAL TESTS Carter, J P; Brooker, J R; Wroth, C P Proc 3rd Australia-New Zealand Conference on Geomechanics, Wellington, 12-16 May 1980, V2, P121-126. Publ Wellington: New Zealand Institution of Engineers, 1980 The concepts of critical state soll mechanics have been used to develop a simple mathematicsl model which predicts many aspects of the beh~vlour of clays under repeated loading. The model employs the parameters that are usually associated with the Cam-clay family of models together with an additional parameter which chsracterises the cyclic behaviour. Numerical studies are made of the behaviou~ of the model urder cyclic triaxial test conlitlons. Predict i o ~ are compared with the results of laboratory tests on a saturated clay. Auth. 826031 RATIONAL APPROACH TO THE POINT LOAD TEST Read, J R L; Thornton, P N; Regan, w M Proc 3rd Australla-New Zealand Conference on Geomechanlcs, Wellington, 12-16 May 1980, V2, P35-39. Publ Wellington: New Zealand Institution of Engineers, 1980 Conversion factors correlating point load strength with unlaxial compressive strength are subject to errors. In additlon test results may be ~ffected by sample anisotropy. Examples are given to show that provided these limitations are recognised the test can be successfully used to measure the strength of rock samples and classify rock. Auth. 826032 SOME PLASTICTTY SOLUTIONS RELEVANT TO THE BEARING CAPACITY OF ROCK AND FISSURED CLAY. JOHN JAEGER MEMORIAL LECTURE Davis, E H Proc 3rd Australla-New Zealand Conference on Geomechanlcs, Wellington, 12-16 May 1980, V3, P27-36. Publ Wellington: New Zealand Institution of Engineers, 1980 Examines the theoretical effects of seml-brittle or strain softening behaviour and the presence of defects, such as Joints and fissures, on the stability of soil and rock masses. This is done by analysing results from box models to determine the surface bearing capacity under plane strain conditions and under mouotonically increasing or single load application. Cyclic loading of footings is briefly considered 0
Deformation characteristics 826033 DEFORMABILI'Iqf OF LAYERED OR JOINTED ROCK MASSES: ANALYSIS AND CC~PARISON OF DIFFERENT TYPEs OF TEA
129A
Bayly, B; Cousens, E Int J Rock Mech Min Sci, VI9, ~ , P195-199
Aug 1982,
Tests using a borehole Jack or a pressure plate on tunnel wall are unsuitable for layered or Jointed rock masses. Such rock masses possess five deformability measures (2 Youngts moduli, 2 Poisson's ratios and the sheer modulus) stud the procedures mentioned, which were developed for measuring just two parameters, are not adaptable. Jack tests on in situ blocks that have been partly isolated by saw-cuts are more suitable, perhaps in conjunction with seismic methods.
826034 S(~4E ELemeNTS
OF A THEORY FOR IN-SITU S~I~ESS. TECHNICAL NOTE McCutchenj W R Int J Rock Mech Min Sci, vIg, ~ , Aug 1982s P201-203 Presents the elements of an in situ stress theory which accounts for the anc~sl@~s behaviour of K (the ratio of average horizontal stress to vertical stress): K being greater than 1 at shallow depths but becoming less than 1 at great depths, eventually reaching a constant value° The method is applied to a model of a self-gravitating spherical shell situated on an unyielding, massive, interior body. The resulting stress- strsin relations are then applied to observed data in the earth's crust.
826035 P R E S ~ TEST IN A HOMOGENEOUS LINEARLY ElAsTIC CROSS-ANISOTROPIC SOILo TECHNICAL NOTE Warren, S J Geotechnique, V32, N2, June 1982, P157-159 Gives an analysis showing that in a cross-anisotropic soil the pressur~neter test yields values of the horlzontal-to-horizontal sheer modulus, which can be used in predicting deformations.
826o36
CONSEQUENCES OF DEVIATORIC NORMALITY IN PLASTICITY WITH ISOTROPIC STRAIN HARDENING. SHORT COMMUNICATION Baker, R; Desal, C S; Int J Num Anal Meth Geomech, V6, N3, July-Sept 1982, P383-390 For mar~ soils experimental evidence suggests that deviation from nc~mallty between the plastic strain increments and the yield function is exhibited mainly in the voltametric behavlour, whereas the deviatoric behavio~r e~xhibits ne~nnality. An analysis of the consequence of this observation is presented, and it leads to an expression for the plastic potential function as composed of two functions: a yield function and another depenlent only on the hydrostatic l~'e ssl/re.
826037 RESILIENT CHARACTERISTICS OF BRAZILIAN SOILS de Medina, J; Preussler, E S J Geotech Engng Div ASCE, V108, NGTS, May
1982, P697-712 Resilient properties of twenty soil samples from subgrades, sub-bases, and mechanically stabilised soil bases of flexible pavements in the South and Southeast of Brazil were evaluated. Soils are mostly residual in origin. Correlations of resilient moduli with confining pressure or deviator stress were established. Co~relations of resilient moduS/ with CBR values were established for finp~Irained soll samples.
A tentative soil classification according to resiliency is developed. Also reference Is made to the applications to pavement deflection calculstions. Auth. 826038 ELASTIC AND PLASTIC STRAIN PROPERTIES OF SAND. TECHNICAL NOTE Ting, C S J Geotech Engng Div ASCE, VI08, NGTS, May 1982, P787-793 Reports measurements of the elastic and plastic volumetric and axial strains of samples of medium sand with 2 different unit weights. The tests were carried out in s. conventional triaxial apparatus with loading and unloading, under conditions of hydrostatic and deviator stress, up to a maximu~n hydrostatic stress of 4 k ~ s q cm. 826039 ELASTIC BEHAVIOUR OF NORMALLY CONSOLIDATED CLAY Ohmaki, S Proc 3rd Australia-New Zealand Conference on Geomeehanics, Wellington, 12-16 May 1980, V2, P127-132. Publ Wellington: New Zealand Institution of Engineers, 1980 In this paper the elastic strain of soil is assumed to consist of two components: one caused by changes in stress ratio and the other by changes in meaneffective stress. These 2 components were studied by conducting triaxial drained tests with various stress paths on samples of consolidated clay. Based uponthese results, an empirical law for stress-straln behaviour under axisymmetric conditions is proposed. 826040 AUTOMATIC JOINT EI]~MENT GENERATION TO SIMULATE STRAIN SOFTENING YIELD BEHAVIOUR IN EARTHEN MATERIALS Richards, B G Proc 3rd Australla-New Zealand Conference on Geemechanics, Wellington, 12-16 May 1980, V2, P233-239o Publ Wellington: New Zealand Institution of Engineers, 1980 This paper describes a model incorporating automatlcally generated joint elements to simulate the observed behaviour of strain softening materials, including the post-yield behaviour. Good agreement was obtained when this model was used to back analyse triaxial and direct shear tests of such material. The collapse load of strip footings as predicted by this model was also compared with previously published results, giving excellent agreement.
Surface properties 8260~1 CERCHAR AHRASIVITY INDEX AND ITS RELATION TO ROCK MINERALOGY AND PETROGRAPHY Sua~as M; Petersj T Rock Mech, VIS, NI, June 1982, PI-8 To evaluate the relation between the Cerchar Abrasivity Index (a parameter used in calculating advance rates of full face turmelling machines) and the petrography of the rocks, measuremerits were made on minerals and monemineralic rocks. From these data a thearetical abrasivity (quartz equivalence) can be calculated for every rock c~nposition. From the comparison of the theoretical and experimentally determined abrasivity the influence of fabric and other factors besides mineralogical composition were deduced. A u t h .