Showing papers on "Direct shear test published in 1988"
TL;DR: In this article, a multistage direct shear test was performed on saturated and unsaturated specimens of a compacted glacial till and the results showed that the axis-trajectory shear was effective on both unsaturated and saturated specimens.
Abstract: Multistage direct shear tests have been performed on saturated and unsaturated specimens of a compacted glacial till. A conventional direct shear apparatus was modified in order to use the axis-tra...
299 citations
TL;DR: In this paper, a method of test for bond should reflect a typical in-service stress state yet also be sensitive to variation in the strength of the bond, and a slant shear test was found to be the most appropriate.
Abstract: When new concrete is placed next to old concrete, attempts are usually made to bond the two concretes together: ofen a cement paste or mortar joint is used, as in masonry. The service stress states in bonds can vary tremendously so no single test method can replicate all these states. A method of test for bond should reflect a typical in-service stress state yet also be sensitive to variation in the strength of the bond. Four tests were evaluated, and a slant shear test was found to be the most appropriate. The effects of various parameters were evaluated theoretically with the finite element and/or experimentally. A bond material with a modulus of elasticity similar to the adjacent concrete was found to be desirable, as was consistency in the bond material properties. Thick bond layers were found to reduce bond strength considerably and copolymer polyvinyl acetate was found to be a poor bonding agent over a wide range of curing conditions and mortar mix designs.
159 citations
TL;DR: In situ shear tests were performed on soils reinforced by roots as mentioned in this paper, and the shear strength measured by the in situ tests were found to be less than the shearing strength along a potential slip surface in slope stability problems.
Abstract: In situ shear tests were performed on soils reinforced by roots. Analytical models of soil‐root interaction presented in a companion paper were used to compute the forces in the roots and the contribution of the roots to the shearing resistance of the soil‐root system. General agreement between measured and computed shearing resistances was taken as verification of the analytical models. Results of the computations also showed the influence of the dimensions of the shear box on the measured shear strength. The shear strengths measured by the in situ tests were found to be less than the shear strength along a potential slip surface in slope stability problems. Methods for estimating the shear strengths for stability analysis are presented.
114 citations
TL;DR: In this paper, two-way strain controlled cyclic simple shear tests under the undrained condition are carried out for normally consolidated and overconsolidated Kaolinite clay.
91 citations
TL;DR: In this paper, a crack rail shear (CRS) specimen is used to characterize the Mode III interlaminar fracture toughness of continuous-fiber-reinforced composite materials and an analytical expression for the strain energy release rate is developed based on a strength of materials approach.
79 citations
TL;DR: In this article, a conventional direct shear box was modified to accommodate the testing of an unsaturated soil, and the design concepts and necessary modifications to the apparatus were described, and a multistage testing procedure was outlined.
Abstract: A conventional direct shear box was modified to accommodate the testing of an unsaturated soil. The design concepts and necessary modifications to the apparatus are described. A multistage testing procedure is outlined. Typical results from direct shear tests are presented. The results illustrate the relationship between suction and shear strength for a glacial till soil.
79 citations
TL;DR: In this paper, the size effect in shear strength of longitudinally reinforced beams is studied by means of a nonlinear fracture mechanics model, and the structure size should be normalized to an intrinsic length parameter of the concrete.
Abstract: The size effect in shear strength of longitudinally reinforced beams is studied by means of a nonlinear fracture mechanics model. According to the actual theoretical study, structure size should be normalized to an intrinsic length parameter of the concrete. This length parameter is proportional to the fracture energy G//F of the concrete. It is found that the shear strength of a concrete beam may be equally sensitive to G//F as to the tensile strength of the concrete. It is concluded that G//F should be measured during experimental studies of the shear strength of beams and the punching strength of slabs. A simple method for considering the intrinsic length parameter in existing shear strength formulas is proposed.
73 citations
TL;DR: In this paper, a torsional simple shear-resonant column device was used to perform experiments on hollow cylindrical samples consisting of glass spheres with two different diameters.
Abstract: A torsional simple shear-resonant column device was used to perform experiments on hollow cylindrical samples consisting of glass spheres with two different diameters. The purpose of the investigat...
53 citations
TL;DR: In this article, a rotary shear machine was designed for testing rock surfaces, especially the shear strength of rock surfaces separated by an infilling of weaker material, which was constructed in 1986 and has recently been used to complete a series of trial tests on clean, flat rock surfaces and similar surface separated by clean rock gouge.
Abstract: This note describes a rotary shear machine similar to those designed by Bishop, Green, Garga, Andersen & Brown (1971) and Bromhead (1979), but suitable for testing rock surfaces, especially the shear strength of rock surfaces separated by an infilling of weaker material. The machine was constructed in 1986 and has recently been used to complete a series of trial tests on clean, flat rock surfaces and similar surfaces separated by clean rock gouge. It was specifically designed to accurately measure shear parameters up to peak failure and to follow these parameters beyond failure to their residual or basic angle of friction. This permits an accurate study of the mechanisms governing shear resistance in rock joints which are subjeced to large displacements.
34 citations
TL;DR: Spatial microheterogeneity might be related to the effects of the shear field in the alignment of filaments, and the balance between a three-dimensional network and a microheterogeneous system appears related to both shear and the presence of actin-binding proteins.
Abstract: The diffusion coefficients and fluorescence polarization properties of actin subjected to a known shear have been determined both during and after polymerization, using a modification of a cone-plate Wells-Brookfield rheometer that allows monitoring of samples with an epifluorescence microscope. Fluorescence polarization and fluorescence photobleaching recovery experiments using rhodamine-labeled actin as a tracer showed that under conditions of low shear (shear rates of 0.05 s-1), a spatial heterogeneity of polymerized actin was observed with respect to fluorescence intensity and the diffusion coefficients with actin mobility becoming quite variable in different regions of the sample. In addition, complex changes in fluorescence polarization were noted after stopping the shear. Actin filaments of controlled length were obtained using plasma gelsolin (gelsolin/actin molar ratios of 1:50 to 1:300). At ratios of 1:50, neither spatial heterogeneity nor changes in polarization were observed on subjecting the polymerized actin to shear. At ratios of approximately 1:100, a decrease on the intensity of fluorescence polarization occurs on stopping the shear. Longer filaments exhibit spatial micro-heterogeneity and complex changes in fluorescence polarization. In addition, at ratios of 1:100 or 1:300, the diffusion coefficient decreases as the total applied shear increased. This behavior is interpreted as bundling of filaments aligned under shear. We also find that the F-actin translational diffusion coefficients decrease as the total applied shear increases (shear rates between 0.05 and 12.66 s-1), as expected for a cumulative process. When chicken gizzard filamin was added to gelsolin-actin filaments (at filamin/actin molar ratios of 1:300 to 1:10), a similar decrease in the diffusion coefficients was observed for unsheared samples. Spatial microheterogeneity might be related to the effects of the shear field in the alignment of filaments, and the balance between a three-dimensional network and a microheterogeneous system (containing bundles or anisotropic phases) appears related to both shear and the presence of actin-binding proteins.
32 citations
TL;DR: In this article, the effects of irregular and multi-directional load application on soil deposits during earthquakes were clarified by applying six sets of irregular shear stress from two mutually perpendicular directions in the simple shear test device.
Dissertation•
01 Jan 1988
TL;DR: In this paper, the compression behavior, shear strength characteristics, and material properties of dense slurries and soft settled beds of natural fine-grained sediments were studied experimentally.
Abstract: The compression behaviour, shear strength characteristics, and material properties of dense slurries and soft settled beds of natural fine-grained sediments were studied experimentally. Slurries of varying initial density, initial height, and pore fluid salinity were settled one-dimensionally, by self-weight, in the laboratory. Settling behaviour was studied in terms of slurry appearance, particle segregation, height of surface versus time, sediment surface and element settlement rates, and the redistribution of sediment with respect to height and time. Consolidation behaviour was studied in terms of sediment compressibility and pore fluid flow. Shear strength was examined "in situ" and elated to the parameters effective stress and specific volume. Instruments and techniques were developed to facilitate the measurement of low effective stresses, low strengths, and high specific volumes. A small scale sediment sampler was developed and used in an attempt to study the arrangement of particles within soft sensitive beds. The experimental results revealed numerous fundamental reasons why theoretical models of settling and consolidation are unsatisfactory when applied to dense flocculated slurries and beds of high specific volume, respectively. For the sediment studied, well-defined compressibility and shear strength relationships were observed. Pore fluid flow relationships were non-unique at high specific volumes. The compression behaviour of slurries was found to have a rational basis in terms of electrochemical forces and degrees of particle association. The experimental results are relevant to engineering practice. Recommendations are made regarding future research.
TL;DR: In this paper, a methodology to assess the permanent deformation of earth fills such as dams and embankments subjected to a shaking of an earthquake is presented, which consists of a hybrid use of the static and dynamic response analyses and the laboratory soil tests by means of the triaxial torsion shear test apparatus.
01 Jan 1988
TL;DR: In this paper, two large scale model reinforced soil walls were constructed within the soil retaining wall test facility at the Royal Military College, Kingston, Canada, for the purpose of testing the stability of soil retaining walls.
Abstract: Two (2) large-scale model reinforced soil walls were constructed within the soil retaining wall test facility at the Royal Military College, Kingston, Canada.
TL;DR: The stress state in many practical geotechnical problems is analogous to simple shear strain this article, and the devices available to test soil samples in Simple Shear strain impose nonuniform stress and...
Abstract: The stress state in many practical geotechnical problems is analogous to simple shear strain. However, the devices available to test soil samples in simple shear strain impose nonuniform stress and...
TL;DR: In this article, a load transfer model was proposed to predict tension forces in reinforced soil inclusions under expected working loads, assuming an elastoplastic strain hardening behavior for the soil and an elastic-perfectly plastic behaviour for the reinforcement.
Abstract: Results of both triaxial and direct shear tests on reinforced soil samples performed by different investigators have shown that soil dilatancy and extensibility of the reinforcements have a significant effect on the generated tension forces in the inclusions. An appropriate soil--reinforcement load transfer model, integrating the effect of soil dilatancy and reinforcement extensibility is therefore needed to adequately predict forces in the inclusions under expected working loads. This paper present a load transfer model assuming an elastoplastic strain hardening behaviour for the soil and an elastic--perfectly plastic behaviour for the reinforcement. This model is used to analyse the response of the reinforced soil material under triaxial compression loading. A companion paper present the application of this model for numerical simulations of direct shear tests on sand samples reinforced with different types of tension resisting reinforcements. The model allows an evaluation of the effect of various parameters such as mechanical characteristics and dilatancy properties of the soil, extensibility of the reinforcements, and their inclination with respect to the failure surface, on the development of resisting tensile stresses in the reinforcements. A parametric study is conducted to evaluate the effect of these parameters on the behaviour of the reinforced soil material. An attempt is also made to verify the proposed model by comparing numerical predictions with available experimental results of both triaxial and direct shear tests on reinforced soil samples. This model can be used for analysis and design of reinforced soil walls with different types of tension resisting inclusions to predict tension forces under expected working loads.
TL;DR: In this article, the shear properties obtained by vane tests are compared with those by a direct shear test (shear box) and an unconfined compression test, and the differences of shear property among these three tests are discussed.
TL;DR: In this paper, the authors provide a brief review of the very limited data available on the size effect on strength of soils and present the results of an investigation of this effect on the drained strength of two residual soils derived from basalt.
Abstract: This paper first provides a brief review of the very limited data available on the size effect on strength of soils Then it presents the results of an investigation of this effect on the drained strength of two residual soils derived from basalt The dense basaltic soil, derived from weathering of columnar basalt, is fissured, whereas the vesicular basaltic soil, product of weathering of amygdaloidal basalt, is remarkably free of discontinuities The results of tests on 500 mm square, 100 mm square, and 635 mm diameter direct shear tests, as well as on 36 mm diameter triaxial samples were obtained The data clearly indicate the significant effect of fissures on the strength of dense basaltic soil, whereas the effect is absent in the vesicular soil The reduction in strength with size in the former can be attributed almost totally to a loss of the cohesive component of shear strength In the absence of tests on large-sized samples, a method is suggested to estimate the mass strength of such soils from re
Journal Article•
TL;DR: In this paper, a series of drained tests on Lias clay at various normal stresses in both a reversible shear box and a modified Bromhead ring shear apparatus were performed, and the results indicated that residual failure surfaces are not developed at normal stresses below 30 kN/sq m (4.4 lb/sq in.).
Abstract: This paper describes a series of drained tests on Lias clay at various normal stresses in both a reversible shear box and a modified Bromhead ring shear apparatus. The residual failure envelopes were found to be curved at normal stresses below 150 kN/sq m (22 lb/ sq in.). At normal stresses above this value, the modified Bromhead ring shear tests produced lower values of residual shear strength than reversal shear box tests. The results indicate that residual failure surfaces are not developed at normal stresses below 30 kN/sq m (4.4 lb/sq in.).
TL;DR: In this paper, the authors investigated the behaviour of a relatively long soil block containing an undulating weak zone of finite thickness, and examined the effect of the thickness and amplitude of the weak zone on the overall strength and deformation of the block.
Abstract: This paper investigates the behaviour of a clay layer containing an undulating shear surface, when sheared across the undulations. A relatively long soil block containing an undulating weak zone of finite thickness is assumed. A finite element study is undertaken, examining the effect of the thickness and the amplitude of the weak zone on the overall strength and deformation of the block. Also examined is the behaviour of the block when either only the weak zone or both the weak zone and the intact soil are strain softening. Key words: undulating shear surface, finite elements, strain softening.
01 Jan 1988
TL;DR: In this paper, direct shear test data for parent material and bonded and unbonded jointed specimens of conventional and RCC (roller compacted concrete) are presented and compared and recommendations made regarding shear strength values for lift joints in gravity dams constructed of RCC.
Abstract: Direct shear test data for parent material and bonded and unbonded jointed specimens of conventional and RCC (roller compacted concrete) are presented and compared. Results are discussed and recommendations made regarding shear strength values for lift joints in gravity dams constructed of RCC. Some discussion is presented on safety factors used in analyses.
TL;DR: In this paper, a discussion of the paper which was published in Geotechnique volume 38, no. 1 (1988) is presented, which concludes that direct shear tests are carried out with boundary conditions which are intermediate in type, and, in consequence, precise data interpretation is difficult.
Abstract: This is a discussion of the paper which was published in Geotechnique volume 38, no. 1 (1988). This is the concluding contribution of the discussion. It notes that direct shear tests are carried out with boundary conditions which are intermediate in type, and, in consequence, precise data interpretation is difficult. The most reliable way to evaluate direct shear data is to compare them with good quality plane strain data from an apparatus in which known boundary stresses are applied uniformly to the sample. The simplicity of the symmetrical conditions advocated by Jewell and Wroth is appealing and the lower shearing resistance measured may be appropriate to many field situations.
TL;DR: In this paper, an experimental evaluation of the ASTM D 4255 two-rail shear test has been carried out for the fatigue of unidirectional E-glass/913 epoxy.
Abstract: An experimental evaluation of the ASTM D 4255 two-rail shear test has been carried out for the fatigue of unidirectional E-glass/913 epoxy. Results from the standard configuration were unsatisfactory with scatter on fatigue life of three orders of magnitude. A close examination of specimens revealed the presence of longitudinal cracks from the specimen free edge caused by the transverse loading component from rail bending. Specimens with such cracks had long lives while specimens without had short lives. The coupon configuration was thus modified with the inclusion of small slots at the location of the longitudinal cracks. This modification greatly decreased scatter of both static strength and fatigue life. Finite-element work showed a consistent shear field in the gage area of the slotted coupon. Experimental work showed a slightly lower value of stiffness from the modified coupon. An effective gage length for the slotted coupon was deduced. A useful S-N curve for unidirectional glass/epoxy in shear has been produced from a simple modification to an existing static shear test method. Its applicability to other materials and layups has been commented upon.
TL;DR: In this paper, an exponential function was proposed to model the wheat-structural material frictional behavior and the average relative differences between model simulations and experimental data were 15.96%, 9.76%, 11.78%, and 9.54% for wheat-aluminum, wheat-galvanized steel, wheatplywood and wheat-concrete interfaces.
Abstract: DIRECT shear tests were performed to study fric-tional behavior of wheat on aluminum, galvanized steel, plywood and concrete. The results showed that the conventional coefficient of friction concept defines the upper bound of tangential force along the contacting surfaces. The magnitude of tangential force is dependent on both the normal force and relative displacement between grain and structural material surfaces. An exponential function was proposed to model the wheat-structural material frictional behavior. Tests were performed to determine the frictional behavior of 10.2% moisture content (w.b.) wheat on four structural materials. Model simulations compare favorably with test data. The average relative differences between model simulations and experimental data are 15.96%, 9.76%, 11.78% and 9.54% for wheat-aluminum, wheat-galvanized steel, wheat-plywood and wheat-concrete interfaces.
13 Jun 1988
01 Jan 1988
TL;DR: In this paper, three holes were cored at Site 630 during Leg 101 of the Ocean Drilling Program and whole-round samples were tested for geotechnical analyses from Hole 630B. Results from triaxial and direct shear testing indicate that Section 101-630B-2H-5 has a higher degree of cohesion and a higher angle of internal friction (0) than sediment recovered deeper in the section, although angles of external friction from all three samples are lower than typical angles measured from deep-sea foraminiferal ooze.
Abstract: Three holes were cored at Site 630 during Leg 101 of the Ocean Drilling Program. Whole-round samples were ob tained for geotechnical analyses from Hole 630B. Consolidation studies, which relate changes in the coefficients of con solidation, compressibility, and permeability to the overburden pressure, indicate that sediments recovered to 79.4 mbsf (meters below seafloor) are not significantly consolidated. This may be a function of total carbonate content, mineral ogy, and type of carbonate constituents. The lower total porosity and permeability of Section 101-630B-2H-5 relative to 101-630B-5H-6 and 101-630B-9H-6 are explained in terms of effective fluid flow, total calcium carbonate content, and type of constituents present. Results from triaxial shear testing and direct shear testing indicate that Section 101-630B-2H-5 has a higher degree of cohesion and a higher angle of internal friction (0) than sediment recovered deeper in the section, although angles of internal friction from all three samples are lower than typical angles measured from deep-sea foraminiferal ooze. At tempts to compare triaxial shear results qualitatively with measurements of undrained vane shear strength from Hole 630A suggest that the latter may be meaningless if taken from sediments dependent on overburden pressure to maintain strength. Calculations based on consolidated and drained shear strength suggest that if the sediment column is homogeneous, the slope will be stable to 14° of inclination. If the inhomogeneities in the section, such as the turbidite layers known to be present, are weaker than the sediments tested, then the stable slope inclination may be less than that calculated. This is substantiated by the abundance of seismic evidence for slumping, sliding, and imbricate thrusting on this gentle (2°3°) slope.
Journal Article•