Shear Strength Of Sand Research Articles

Shear Modulus and Cyclic Undrained Behavior of Sands

The results of laboratory experiments performed to investigate the effects that factors such as fabric, anisotropic consolidation and stress-strain history have on the shear modulus at very small strains (G0), on the drained modulus degradation curve, and on the cyclic undrained shear strength of sands are summarized. The results presented show that G0 is relatively insensitive to sand fabric, initial stress ratio, monotonic prestressing, and cyclic strain history. Thus, specimens with the same G0 can exhibit very different behaviors in cyclic undrained shear, depending upon their initial fabric, initial stress ratio, or stress-strain history. To a lesser degree, this is also true for the shear modulus (G) at larger strains, as interpreted in the conventional manner from drained cyclic shear tests (unload/reload modulus). Based on these findings, the limitations involved in the use of G0 and G to interpret behavior in cyclic undrained shear are discussed.

Shear strength of sands during increasing pore pressure : Kaczynski, R R Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 20–25 October 1986V2, P981–989. Publ Rotterdam: A A Balkema, 1986

Shear strength of sands during increasing pore pressure : Kaczynski, R R Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 20–25 October 1986V2, P981–989. Publ Rotterdam: A A Balkema, 1986

Interpretation of the results of shear tests of sands

This paper investigates the main factors which determine the shear strength of sands and assesses such properties as the angle of internal friction, density, porosity, saturation, moisture content, residual strength, stress-strain state, and vertical and horizontal deformation for their contributions to the shear strength. Issue is taken with the conclusion of an earlier study that the density has no effect on the angle of internal friction. It is concluded that the bearing capacity of sands should be calculated with consideration of the effect of their density.

Cyclic undrained triaxial and torsional shear strength of sands for different sample preparation methods : Tatsuoka, F; Ochi, K; Fujii, S; Okamoto, M Soils FoundV26, N3, Sept 1986, P23–41

Cyclic undrained triaxial and torsional shear strength of sands for different sample preparation methods : Tatsuoka, F; Ochi, K; Fujii, S; Okamoto, M Soils FoundV26, N3, Sept 1986, P23–41

Cyclic Undrained Triaxial and Torsional Shear Strength of Sands for Different Sample Preparation Methods

The effects of sample preparation methods on the cyclic undrained stress-strain behavior of sands were investigated by means of triaxial and torsional shear tests using two kinds of clean sands and one kind of sand including fines, with a wide variation in the sample density. Four different sample preparation methods were adopted; air-pluviation, wet-tamping, wet-vibration, and water-vibration. The differences in the effects of sample preparation methods were found to be significant in both testing methods. However, specific ways in which the sample preparation methods affected the results were not consistent between the triaxial and torsional shear tests. This indicates that the process of estimating cyclic undrained simple shear strengths from triaxial strengths is not as simple as has previously been considered. It was found that in torsional shear tests the shapes of strength curves in the planes of the cyclic stress ratio and the logarithm of the number of cycles Nc are similar for different sample preparation methods, in the sense that the different curves collapse into a single curve when these curves are moved appropriately along the log Nc-axis. It was also found that for the same sample density the effects of the sample preparation method on the cyclic undrained stress-strain behavior decrease with the increase in strain. A new density index is proposed, from which the cyclic undrained behavior can be estimated for different sample preparation methods and for different kinds of sands until the shear strain becomes around 3% in double amplitude.

Statistical Evaluation of Cyclic Strength of Sand

A statistical model is proposed to estimate the cyclic shear strength of a saturated sand deposit. Large-scale shaking table test results are used to develop the basic model since they reproduce the in situ test conditions more closely than other laboratory tests. Due to the unavailability of large-scale shaking table test results for different soils and test conditions, cyclic triaxial test results are used to modify this basic model. The model is first developed to represent laboratory conditions. This laboratory relationship is then modified for in situ conditions. Factors affecting laboratory relationships that are considered in this study are methods of sample preparation, soil fabric, system compliance, mean grain size, multidirectionality of earthquake motions, and secondary factors. Factors affecting the in situ relationship are previous strain history, age, cementation, etc. It is observed that considerable uncertainty is expected in the estimation of the in situ cyclic shear strength. The uncertainty associated with the in situ relative density contributes significantly to the overall uncertainty. This type of uncertainty needs to be considered in any analysis where the cyclic shear strength of sand is an important parameter, e.g., liquefaction.

Experimental study of anisotropic shear strength of sand by plane strain test : Oda, M; Koishikawa, I; Higuchi, T Soils Found, V18, N1, March 1978, P25–38

Experimental study of anisotropic shear strength of sand by plane strain test : Oda, M; Koishikawa, I; Higuchi, T Soils Found, V18, N1, March 1978, P25–38

Experimental Study of Anisotropic Shear Strength of Sand by Plane Strain Test

ABSTRACT Anisotropic parallel alignment of particles is universally observed not only in river, beach and coastal dune sands but also in artificially deposited sands. Anisotropic shear strength caused by the anisotropic parallel alignment of particles can be observed more clearly in the plane strain condition e2 = 0 than in the symmetrical stress condition σ2 = σ3. This must be chiefly due to the fact that re-arrangement of particles during shear deformation can be more easily performed in the latter condition than in the former one. Shear strength of sand in a plane strain test has been generally believed to be 10% to 20% greater than that obtained in a triaxial compression test. When the specimen is compressed at a small angle to a bedding plane, however, it is possible that the shear strength in the plane strain test is smaller than that in the triaxial compression test. The effect of anisotropic shear strength cannot be ignored when stability problems and earth pressure problems in plane strain condition are analyzed.

Shearing properties of sand under a repeated loading representing the ground pressure distribution of a tracked vehicle

This paper deals with experiments concerning the shearing properties of sand under repeated loading simulating the ground pressure distribution of a tracked vehicle. Shearing tests were carried out in sand by using a direct shear apparatus. It was confirmed that the shear strength of sand under repeated loading decreases with an increase in the number of loadings. This influences the soil thrust exerted by a highspeed tracked vehicle.

Shear Strength of Sand at Constant Volume

Abstract To verify the expressions developed by other researchers for separating the strength component resulting from volume change in shear (dilatancy), shear tests at constant volume as well as drained tests are necessary. In conventional undrained triaxial tests on granular materials, volume change of the soil skeleton occurs as a result of rubber membrane penetration. In the present investigation, conventional tests were modified to ensure a constant volume condition by compensating for the rubber membrane penetration. Drained tests, conventional undrained tests, and modified undrained tests were conducted on a uniform medium sand, uniform coarse sand, and a gap-graded sand; the results are compared. Conventional undrained tests gave somewhat higher values of shear strength than those of modified undrained tests. The results of drained tests corrected for volume change compare well with those of modified undrained tests.

Shear strength of sand under general stress system : Ramamurthy, T IIT, Delhi, Ind Rawat, PC IIT, Delhi, Ind Conference. Session one. 2F, 1T, 19R Proc. Eighth Int. Conf. on Soil Mech. Found. Engng, Moscow, 1974, V1.2, 1974, P339–342

Shear strength of sand under general stress system : Ramamurthy, T IIT, Delhi, Ind Rawat, PC IIT, Delhi, Ind Conference. Session one. 2F, 1T, 19R Proc. Eighth Int. Conf. on Soil Mech. Found. Engng, Moscow, 1974, V1.2, 1974, P339–342

Shear strength of sand at extremely low pressures: 95. V. M. Ponce and J. M. Bell.J. Soil Mech. Fndns. Div., Proc. ASCE, 97 (SM 4) Paper 8062, pp. 625–638 (April 1971)

Shear strength of sand at extremely low pressures: 95. V. M. Ponce and J. M. Bell.J. Soil Mech. Fndns. Div., Proc. ASCE, 97 (SM 4) Paper 8062, pp. 625–638 (April 1971)

Shear Strength of Sand at Extremely Low Pressures

Data contributing to the understanding of the nature of shear strength at extremely low pressures are presented. The expanding use of models for solving soil stability problems has aroused considerable interest in the behavior of sand at confining pressures below 5 psi. Triaxial compression tests were carried out varying the cell pressure between 0.20 psi and 35 psi. Experimental evidence shows that the increased dilatancy of sands sheared at extremely low pressures produces an increase in the principal stress ratio at failure. The overall increase in strength is mostly represented by the introduction of an apparent cohesion intercept. Values of this intercept for the quartz sand tested range from 0.14 psi at loose states to 0.22 psi at dense states. Values of the angle of shearing resistance at extremely low pressures are smaller than those obtained at moderate pressures by less than 0.5°. For loose states, shear can be associated with expansive volume change if the normal pressures are low enough. The shearing behavior of loose sands at very low pressure is quite similar to that of dense sands at moderate pressure.

The Relationship between the Shear Strength of Sands in Triaxial Compression, Plane Strain and Direct Shear

Synopsis A theoretical relation is derived between the peak Coulomb φ values for saturated drained sands measured in the direct shear test and the plane strain compression test using the stress-dilatancy equation and the assumption that the directions of principal strain increment and principal stress coincide. Limiting dilatancy rates in triaxial compression allow an overall comparison of the φ values to be expected in these three types of test. Present available experimental data indicate quite close agreement over the range φu = 17°–39° for cohesion-less soils. On derive une relation theorique entre les valeurs φ de pointe de Coulomb pour des sables draines satures mesurees dans l'essai de cisaillement direct et l'essai de compression a deformation en plan en utilisant 1'equation de contrainte-dilatabilite et la supposition que les directions de l'accroissement de deformation principale et de la contrainte principale coincident. Des taux limites de dilatabilite en compression tr axiale permettent de fa...

The Relationship Between the Shear Strength of Sands in Triaxial Compression, Plane Strain and Direct Shear

The Relationship Between the Shear Strength of Sands in Triaxial Compression, Plane Strain and Direct Shear

The Relation Between the Shear Strength of Sands in Triaxial Compression, Plane Strain and Direct

Synopsis A theoretical relation is derived between the peak Coulomb φ values for saturated drained sands measured in the direct shear test and the plane strain compression test using the stress-dilatancy equation and the assumption that the directions of principal strain increment and principal stress coincide. Limiting dilatancy rates in triaxial compression allow an overall comparison of the φ values to be expected in these three types of test. Present available experimental data indicate quite close agreement over the range φu = 17°–39° for cohesion-less soils. On dérive une relation théorique entre les valeurs φ de pointe de Coulomb pour des sables drainés saturés mesurées dans l'essai de cisaillement direct et l'essai de compression à déformation en plan en utilisant 1'équation de contrainte-dilatabilité et la supposition que les directions de l'accroissement de déformation principale et de la contrainte principale coincident. Des taux limites de dilatabilité en compression tr axiale permettent de faire une comparaison d'ensemble des valeurs φ auxquelles on peut s'attendre pour ces trois types d'essais. Les données expérimentales disponibles actuelles indiquent une concordance trés proche dans le cas où la gamme des valeurs de φu = 17° – 39° pour les sols sans cohésion.

New state standard "Soils. Method of Laboratory Determination of Shear Strength of Sands and Clays in Box Apparatus under Conditions of Completed Consolidation" GOST 12248-66. Group Zh39

New state standard "Soils. Method of Laboratory Determination of Shear Strength of Sands and Clays in Box Apparatus under Conditions of Completed Consolidation" GOST 12248-66. Group Zh39

Shear Strength of Sands during Rapid Loadings

Triaxial tests with times-to-failure ranging from 5 min to 5 milliseconds have been used to investigate the effect of strain-rate on the strength of dry and saturated sands. New techniques were dev...

Discussion of “Shear Strength of Sands During Rapid Loadings”

Discussion of “Shear Strength of Sands During Rapid Loadings”

Shear Strength of Sands During Rapid Loadings

Triaxial tests with times-to-failure ranging from 5 min to 5 msec were used to investigate effect of strain-rate on strength of dry and saturated sands; new techniques were developed for applying strains rapidly, and for measuring resultant stresses and pore pressures; peak friction angles of sands tested were substantially independent of failure-time; however, excess pore pressures generated within saturated loose sands did vary with failure-time.