Showing papers on "Direct shear test published in 1973"
TL;DR: In this paper, a sliding scale of roughness is proposed for estimating the shear strength of rough joints, and the curvature of the proposed strength envelopes reduces as the roughness coefficient reduces, and also varies with the strength of the weathered joint wall or unweathered rock.
1,168 citations
87 citations
Journal Article•
TL;DR: The authors showed that RESIDUAL SHEAR STRENGTH IS PRIMARILY DEPENDENT ON MINERAL COMPOSITION and system CHEMISTRY and that STRENGTH and PLASTICITY can be correlated.
Abstract: THE AUTHOR DRAWS ATTENTION TO THE FACT THAT DRAINED DIRECT SHEAR TESTS BY NUMEROUS WORKERS ON NATURAL SOILS, PURE MINERALS AND MINERAL MIXTURES HAVE SHOWN THAT RESIDUAL SHEAR STRENGTH IS PRIMARILY DEPENDENT ON MINERAL COMPOSITION AND SYSTEM CHEMISTRY. THESE NUMERALOGICAL FACTORS AFFECT ATTERBERG INDEX PARAMETERS. IT DOES NOT SEEM SURPRISING THAT STRENGTH AND PLASTICITY CAN BE CORRELATED. /TRRL/
79 citations
TL;DR: In this paper, the authors compare the displacement fields given by an anisotropic continuum model of a jointed rock mass with that obtained from the discrete joint model, and find that the model predicts a stress distribution that is significantly different from Flamant's solution for a strip load on a semi-infinite rock mass.
52 citations
01 Sep 1973
TL;DR: In this article, a new direct shear machine was proposed for jointed sandstone samples under undrained conditions with pore pressure measurement, and the results showed that the pore pressures in jointed specimens continued increasing right up to the peak load.
Abstract: Undrained Shear Testing of Jointed Rock
Water pressures must change inside joints undergoing shear without perfect drainage. This paper describes a new direct shear machine in which jacketed samples with oriented joints can be tested under consolidated undrained conditions with pore pressure measurement. Triaxial compression techniques for such tests are also described and typical results with intact and jointed sandstone samples are compared with results from the direct shear tests. Whereas intact specimens displayed increasing pore pressure followed by dilatancy and pore pressure decline before peak loading, the pore pressure in jointed specimens continued increasing right up to the peak load.
45 citations
TL;DR: In this paper, it was found that the strength of the LUNAR soil is less than that of a ground-basalt simulator in air, and the contrast between the two was shown to be significant.
Abstract: TWO OEDOMETER AND THREE DIRECT SHEAR TESTS HAVE BEEN PERFORMED IN VACUUM ON A 200-G SAMPLE OF LUNAR SOIL FROM APOLLO 12 (SAMPLE NO. 12001, 119). IT HAD BEEN EXPECTED THAT THE VACUUM ENVIRONMENT AND CLEAN PARTICLE SURFACES WOULD CAUSE THE LUNAR SOIL TO HAVE A LOWER COMPRESSIBILITY AND A HIGHER SHEAR STRENGTH THAN THAT OF A GROUND BASALT SIMULANT IN AIR. INSTEAD, IT IS FOUND THAT THE OPPOSITE IS TRUE: THE COMPRESSIBILITY OF THE LUNAR SOIL IS SLIGHTLY GREATER AND THE SHEAR STRENGTH IS SIGNIFICANTLY LESS. THIS DIFFERENCE IS TENTATIVELY ATTRIBUTED TO THE DEGRADATION UNDER STRESS OF FRAGILE LUNAR PARTICLES SUCH AS AGGLUTINATES AND BRECCIAS. OVER THE RANGE OF DENSITIES TESTED, THE TYPICAL VIRGIN COMPRESSION INDEX IS 0.06 AND THE FRICTION ANGLE VARIES FROM 28 DEG TO 35 DEG. LARGE-SCALE PARTICLE CRUSHING OCCURS AT NORMAL STRESSES OF LESS THAN 70 KN/SQ M (10 PSI), AND CONSEQUENTLY, THE MOHR-COULOMB STRENGTH ENVELOPE SHOULD BE EXTREMELY CURVED. THE SHEAR STRENGTH OF OTHER LUNAR SOILS AT THE SAME VOID RATIO WILL PROBABLY VARY ACCORDING TO THE PROPORTION OF FRIABLE PARTICLES. /AUTHOR/
31 citations
21 citations
Journal Article•
TL;DR: In this article, a simple method for determining the COHESION C and INTERNAL FRICTION ANGLE "PHI" of SOILS and STABILIZED MATERIALs, which requires knowledge of only the UNCONFINED COMPRESSIVE STRENGTH and TENSILE STRENGTH, is presented.
Abstract: A SIMPLE METHOD FOR DETERMINING THE COHESION C AND INTERNAL FRICTION ANGLE "PHI" OF SOILS AND STABILIZED MATERIALS, WHICH REQUIRES KNOWLEDGE OF ONLY THE UNCONFINED COMPRESSIVE STRENGTH AND TENSILE STRENGTH, IS PRESENTED. THE TENSILE STRENGTH MAY BE CONVENIENTLY DETERMINED BY THE NEWLY DEVELOPED DOUBLE-PUNCH TEST. A PROCEDURE IS OUTLINED FOR ESTABLISHING C AND "PHI" FROM THE MOHR-COULOMB FAILURE ENVELOPE CONSTRUCTED BY USING THE PROPOSED METHOD. COMPARISONS SHOWING GOOD AGREEMENT BETWEEN STRENGTH PARAMETERS CALCULATED FROM THE PROPOSED METHOD AND THOSE MEASURED BY MORE CONVENTIONAL DIRECT SHEAR AND SPLIT-TENSILE STRENGTH TESTS FOR VARIOUS TYPES OF SOILS ARE GIVEN. /AUTHOR/
18 citations
Journal Article•
TL;DR: In this article, the authors present some additional information to that given by BISHOP and COMMENTS on the RESIDUAL SHEAR STRENGTH of VARIOUS CLAY SHALES as DETERMINED by COMPARATIVE RING SHEAR, MULTIPLE REVERSAL DIRECT SHEAR and ROTATIONAL SHEAR TESTS.
Abstract: THE AUTHORS PRESENT SOME ADDITIONAL INFORMATION TO THAT GIVEN BY BISHOP AND COMMENTS ON THE RESIDUAL SHEAR STRENGTH OF VARIOUS CLAY SHALES AS DETERMINED BY COMPARATIVE RING SHEAR, MULTIPLE REVERSAL DIRECT SHEAR AND ROTATIONAL SHEAR TESTS. DETAILS ARE GIVEN OF THE APPARATUS USED IN THOSE TESTS, AND TABLES PRESENT THE CLASSIFICATION INDEXES, MINERALOGY, AND RESULTS OF RESIDUAL SHEAR STRENGTH TESTS.
4 citations
TL;DR: In this article, the authors present a study on the strength of tailings from a gold mine and find that the tailings have a high strength, which increases with increasing density.
Abstract: DATA ARE PRESENTED ON THE SHEAR STRENGTH OF SILT SIZE TAILINGS FROM A GOLD MINE. THE SLIMES ARE DESCRIBED AND DETAILS ARE GIVEN OF DIRECT SHEAR TESTS. THE RESULTS OF THE TESTS ARE SUMMARIZED IN A TABLE. THE SLIMES WERE FOUND TO HAVE A HIGH SHEAR STRENGTH WHICH INCREASES WITH INCREASING DENSITY. THE HIGH SHEAR STRENGTH IS ATTRIBUTED TO PARTICLE INTERLOCK AND TO ATTRACTIVE ELECTRICAL FORCES BETWEEN THE LAYER LATTICE MINERAL PARTICLES. THE SLIMES EXHIBIT A DECREASE IN SHEAR STRENGTH WITH INCREASING DEGREE OF SATURATION. THIS STRENGTH DECREASE IS ATTRIBUTED TO HYDRATION OF IONS ON THE SURFACES OF THE LAYER LATTICE MINERAL PARTICLES AND THE RESULTING REDUCTION IN ATTRACTIVE INTERPARTICLE ELECTRICAL FORCES. QUALITATIVELY SIMILAR STRENGTH BEHAVIOR MAY OCCURE WITH CERTAIN OTHER FINE GRAINED PARTICULATE MATERIALS (EG. TAILINGS, NATURAL SOILS, AND FAULT GOUGES), WHICH CONTAIN APPRECIABLE QUANTITIES OF LAYER LATTICE MINERAL PARTICLES.
TL;DR: In this paper, a method of preparing isotropic clay soil samples in the laboratory is given, where consolidation is accomplished under hydrostatic pressure, and direct shear tests are performed on specimens trimmed at different inclinations to the physical horizontal from the block samples prepared by this method.
Abstract: A method of preparing isotropic clay soil samples in the laboratory is given, where consolidation is accomplished under hydrostatic pressure. Direct shear tests were performed on specimens trimmed at different inclinations to the physical horizontal from the block samples prepared by this method. The ratio of undrained shear strengths in any direction to that in the vertical direction was found to be practically equal to one. Similar tests performed on specimens trimmed from samples of the same clay consolidated one-dimensionally showed this ratio to be maximum for horizontally trimmed specimens. Thus, for laboratory investigation, where isotropic test specimens are desired, soil samples should be consolidated hydrostatically and not one-dimensionally as the latter yields anisotropic samples.
01 Jan 1973
TL;DR: In this paper, a simple method for determining the cohesion, c, and internal friction angle of stabilized materials requiring knowledge of only the unconfined compressive strength and tensile strength is presented.
Abstract: A simple method for determining the cohesion, c, and internal friction angle, ¢, of soils and stabilized materials requiring knowledge of only the unconfined compressive strength and tensile strength is presented. The tensile strength may be conveniently determined by the newly developed double-punch test. A procedure for establishing c and ¢ from the Mohr-Coulomb failure envelope constructed using the proposed method is outlined. Comparisons showing good agreement between strength parameters calculated from the proposed method and from those measured by more conventional direct shear and split-tensile strength tests for various types of soils are given.
01 Jan 1973
TL;DR: In this paper, a series of shear tests were performed on several prepared samples of granular and powdery bulk materials to investigate the following parameters: Particle size and distribution, particle movement, moisture content, consolidation of material, bulk density, void ratio, porosity, volume change, and strain rate.
Abstract: Shear tests were performed on several prepared samples of granular and powdery bulk materials to investigate the following parameters: Particle size and distribution, particle movement, moisture content, consolidation of material, bulk density, void ratio, porosity, volume change, and strain rate. A series of shear tests was performed with weight-percent-ratios of minus 0.185-inch tertiary sand and 1-/sup 1///sub 2/- by /sup 1///sub 2/-inch tertiary gravel mixtures, and weight-percent-ratios of minus 200-mesh limestone (rock dust) and minus 200-mesh bituminous float coal dust. A comparison was made for shear test results obtained with rectangular and circular shear cells utilizing the large and small direct shear testers. Specifically, the shear results obtained include the angle of internal friction or shear strength of the tested material under known consolidating pressures, and the kinematic angle of friction or coefficient of friction between the interface of a bulk material and a sample wall material. The experimental procedure, tests, and results are given for each parameter investigated.
Journal Article•
TL;DR: In this article, the authors studied the increase in strength of soft clays due to the use of highway embankment and showed that the excess pressure data can be used to quantify the strength gain.
Abstract: THE INCREASE IN SHEAR STRENGTH IN SOFT CLAY DUE TO CONSOLIDATION UNDER HIGHWAY EMBANKMENT LOADING IS STUDIED. VERTICAL SHEAR DRAINS WERE USED TO ACCELERATE THE PROCESS OF CONSOLIDATION. THE GAIN IN SHEAR STRENGTH WAS MEASURED OVER A FOUR-YEAR PERIOD AFTER CONSTRUCTION OF THE EMBANKMENT. IT IS SHOWN THAT THE EXCESS PORE WATER PRESSURE MEASURED IN THE FIELD CAN BE USED TO PREDICT THE INCREASE IN SHEAR STRENGTH WITH REASONABLE ACCURACY. DETAILS ARE GIVEN OF THE SUBSURFACE PROFILE WHICH CONSISTS OF A RELATIVELY HOMOGENEOUS, GRAY BAY MUD COMBINED WITH BROKEN SEASHELLS TO A DEPTH OF 50 TO 70 FEET. LABORATORY SHEAR STRENGTH WAS OBTAINED FROM TESTS ON UNDISTURBED SAMPLES TAKEN FROM BORING HOLES BY USING THE UNCONFINED COMPRESSION TEST (U-TEST) AND THE UNCONSOLIDATED-UNDRAINED TRIAXAIL COMPRESSION TEST (UU- TEST). THE SAMPLES WERE OBTAINED BY EITHER PUSHING A TWO- INCH CALIFORNIA SAMPLER HYDRAULICALLY INTO THE BAY MUD OR PUSHING A SWEDISH FOIL SAMPLER INTO CLAY LAYERS. THE ANALYSIS OF THE SHEAR STRENGTH INCREASE IS PRESENTED, AND THE RESULTS ARE TABULATED AND DISCUSSED. IT IS CONCLUDED THAT EXCESS PORE PRESSURE DATA GENERALLY YIELD A BETTER ESTIMATE OF STRENGTH GAIN AND IS PREFERABLE TO THE USE OF TIME-SETTLEMENT DATA.
Journal Article•
TL;DR: In this article, a model for the FAILURE of a plane at the RESIDUAL SHEAR RESISTANCE is presented, which is based on the same model used in the present study.
Abstract: RENEWED INTEREST IN THE POSTPEAK BEHAVIOUR OF COHESIVE SOILS STIMULATED BY THE FOURTH RANKINE LECTURE (SKEMPTON, 1964) HAS LED TO A NUMBER OF INVESTIGATIONS IN THE RECENT PAST A CLOSE EXAMINATION OF THE VARIOUS INVESTIGATIONS CONCERNED WITH RESIDUAL STRENGTH OF CLAYS INDICATES THE POSSIBILITY OF GROUPING THEM INTO THE FOLLOWING CATEGORIES: (1) DEVELOPMENT OF A SUITABLE LABORATORY TECHNIQUE TO MEASURE RESIDUAL STRENGTH- (A) REVERSING DIRECT SHEAR; (B) TRIAXIAL COMPRESSION; (C) RING SHEAR; (2) INFLUENCE OF GEOMECHANICAL FEATURES ON RESIDUAL STRENGTH- AND (3) LABORATORY STUDIES DIRECTED TO AN UNDERSTANDING OF THE BASIC MECHANISMS INVOLVED IN THE MOBILIZATION OF SHEAR STRENGTH DURING THE RESIDUAL STAGE OF DEFORMATION THE PRESENT INVESTIGATION PERTAINS TO THE LAST CATEGORY, AND IS PRIMARILY CONCERNED WITH THE STUDY OF THE INFLUENCE OF THE FOLLOWING FACTORS ON THE RESIDUAL STRENGTH OF SATURATED REMOULDED CLAYS: (1) CLAY COMPOSITION, (2) MODE OF PRE-CONSOLIDATION STRESS HISTORY (ISOTROPIC AND K0-CONSOLIDATION), (3) ORIENTATION OF SAMPLE (VERTICAL AND HORIZONTAL TO MAJOR PRINCIPAL STRESS DIRECTORS), (4) STRESS HISTORY (NORMALLY CONSOLIDATED AND OVERCONSOLIDATED), (5) TEST CONDITIONS (UNDRAINED AND DRAINED) SATURATED CLAYS IN THE REMOULDED STATE WERE USED TO ELIMINATE THE EFFECTS OF MACRO-STRUCTURAL GEOMECHANICAL FEATURES ON THE BASIS OF EARLIER INVESTIGATIONS, A MICRO- MODEL FOR THE FAILURE PLANE AT THE RESIDUAL SHEARING RESISTANCE IS SUGGESTED