The case of a rigid wall retaining a reinforced cohesionless fill that carries a uniform surcharge load has been analyzed based on the limit equilibrium approach. The reinforcement may be in the form of strips or mats that are not connected to the wall. This analysis considers the stability of an element of the failure wedge, which is assumed to develop in the reinforced earth mass adjoining the back face of the wall. Nondimensional design charts have been developed for computing the resulting lateral earth pressure on the wall and the height of its point of application above the base of the wall. The theoretical findings have been verified in two different sets of model tests on a rigid wall that is retaining a dry sand fill and that is reinforced by aluminium and bamboo strips. Experimental results are in good agreement with the theoretical predictions. An applied example for an 8‐m high wall illustrates the design procedure.

Limit equilibrium methods for slope stability analysis do not, in general, satisfy the overall equilibrium conditions; they must make assumptions regarding the inclination and location of the interslice forces. An alternative slope analysis based on the discrete element method is presented to avoid these drawbacks. A slope in the present model is treated as comprised of slices that are connected by elastoplastic Winkler springs. By considering the conditions of compatibility, stresses on the mobilized surface can be obtained that are statically admissible and consistent with the material strength. The formulation of the method is presented and followed by a comparison of the method with limit equilibrium methods. Examples are also shown that demonstrate the applicability of the method to the analysis of progressive failure involving local yield and subsequent stress redistribution.

Results from a comprehensive experimental program on both loose and dense fine Ottawa silica sand subjected to generalized monotonic loading are presented. The experimental program was conducted on both solid and hollow cylinder specimens, using a new hollow cylinder apparatus, and includes isotropic, triaxial compression, triaxial extension, simple shear, axial/torsional, and other combined tests at various stress levels. This paper presents part of the results with the emphasis placed on generalized failure and yield criteria. The results are compared with predictions using Lade's single‐hardening constitutive model for factional materials based on nonassociated flow plasticity. The comparisons show good agreement between experimental data and model predictions for the failure surfaces for both loose and dense sand. Moreover, very good agreement is shown between experimental data and simulation results for the isotropic, triaxial compression, triaxial extension, and simple shear tests examined.

Membrane compliance in the triaxial test may cause water‐content redistribution and an increase in specimen density during undrained cyclic loading. A reduction in effective confining pressure causes the membrane to rebound from penetration sites and causes pore fluid to migrate to the specimen periphery. As pore fluid is drawn from interior to peripheral voids, the skeletal grain structure contracts to balance the fluid volume. Thus, specimen density at the end of undrained cyclic loading may be considerably higher than the density at the start, even though the test is undrained. Properties measured at the end of the test may not represent actual in situ performance, as the specimen contracted due to membrane compliance. The final specimen density may be determined by measuring volume changes in drained hydrostatic load and unload tests. Volume changes due to membrane penetration may be used to compute changes in density during undrained loading. The basis for this determination is presented in this paper. Results are presented for unsluiced and sluiced gravel specimens.

The three‐dimensional response of La Villita, an earth and rock‐fill dam in Mexico, during the earthquakes of November 15, 1975 and September 19, 1985, is investigated. A simplified numerical procedure is derived to represent upstream‐downstream, and coupled longitudinal‐vertical vibration. This procedure accounts for the dam alluvial foundation and the canyon geometric configuration. Soil behavior is modeled by a nonlinear hysteretic incremental‐plasticity model. Computations are performed using step‐by‐step time‐integration procedures. Accelerations and displacements are computed and compared to those actually observed. The computed (normal and shear) stress and strain histories at various locations within the dam are also shown. In general, the employed computational model is found to predict the magnitude of recorded accelerations with reasonable accuracy. The observed permanent deformations are found to exceed the computed values and are modeled by a simple sliding‐block formulation.

Perceiving granular material as a collection of particles, a constitutive law for granular material is derived based on a micromechanics approach. The constitutive model takes into account the mechanisms of sliding and separation of particles under large deformation. One of the obstacles for modeling particle sliding is the nonuniform strain field under large deformation. In this paper we tackle this problem by introducing a distributive law that describes the heterogeneous strain field. A brief review of the previous work on granular mechanics is presented followed by a description of the current approach. This approach treats the material at three levels, namely, representative unit, microelement and interparticle contact. On this basis the constitutive laws for each level are derived, and the overall stress‐strain relationship is expressed in terms of interparticle contact behavior. The unique features of the present theory are discussed to show its usefulness in comprehensive modeling of complex behavior for granular material.

A micromechanics‐based constitutive model for granular material is evaluated. The predicted stress‐strain behavior for idealized material is compared with that observed from experiments for sands. Under small strain conditions, the model capability is evaluated for predicting initial moduli, secant moduli, and damping ratio with the material is subjected to low‐amplitude loading. Under large strain conditions, the model capability is evaluated for predicting the stress‐strain strength behavior when the material is subjected to various stress paths. In the predictions, three material parameters are used to represent the stiffness and friction of the interparticle contact. Although the predictions are made for idealized spherical particles, the predicted behaviors are found to be remarkably similar to that observed for sands in experiments. The potential capability of the proposed constitutive theory is illustrated, and the model performance is discussed on various aspects of granular material behavior, such as stress‐induced anisotropy, path dependency, plastic flow, dilatancy, and noncoaxial behavior under rotation of principal stress.

Recent advances in polymeric materials have opened up a new alternative of providing additional stability to embankments on soft soils by incorporating polymeric reinforcement in the form of sheet or grid at the base of embankments. A new approach to the analysis of rotational stability of reinforced embankments, based on the work of Low for unreinforced embankments, is presented in the paper. The equation for required reinforcement force for an arbitrary slip circle is set up. From this, the solutions for center of critical slip circle and maximum reinforcement force are obtained in the form of closed-form equations. The design of wide-crested reinforced embankments can be carried out quickly, using the equations and tabular values presented herein.

Clay particles are usually treated as lyophobic colloids and, thus, colloid chemistry provides a means for description of interactions in a clay-water-electrolyte system. The Stern-Gouy-Chapman theory of diffuse double layer has been applied to the behavior of clays with varying degrees of success. In most textbooks, the equations describing the diffuse double layer are given in electrostatic units. However, it is very confusing for researchers of different disciplines to communicate this way, as the existing equations are not even in compliance with the counterparts in electrical engineering. Moreover, it complicates double-layer computations when coupled flows are involved, i.e., one type of flow is induced by another type of force. These problems become apparent as the amount of research in hazardous waste management and site remediation grows. Hence, it is worthwhile to redevelop these equations using the SI system to eliminate these ambiguities and a redundant conversion factor. Moreover, it is shown that the SI equations can be obtained very conveniently by replacing the dielectric constant term in esu equations by the product of 4π and the permittivity of the medium.