Settlement and stability are the primary geotechnical considerations in the design of embankments founded on soft clay. Settlements are inevitably associated with lateral deformations. Lateral flow in turn is an indirect measure of the stability of embankments. Therefore, a detailed study of different settlement components and lateral deformations and their correlations will provide guidelines for an embankment design. This paper presents a new methodology, termed “Field Deformation Analysis (FDA),” which is based on a simple concept dealing with lateral and vertical deformation characteristics of soft foundations under embankment stage loading. This method is used to delineate and quantify different settlement components, namely, immediate settlement, consolidation settlement, and creep settlement, from the total settlement measured during field observations, for the loading and consolidation stages. Finite element method (FEM) of analysis was performed for comparison with FDA results. The FEM analysis was performed using the CRISP computer program, developed at Cambridge University, which uses many soil constitutive models including the modified Cam‐clay model. In 1988, the Malaysian Highway Authority was authorized to build 13 full‐scale test embankments at Muar Flats, of which two were constructed without any foundation ground improvements. A comparison study of the results from FDA and FEM, performed for both the untreated full‐scale test embankments, revealed very good agreement during loading and consolidation stages. In addition, a consistent relationship between the different settlement components was also observed during the different stages of embankment loading.

Engineered soil covers are being evaluated under Canada's Mine Environment Neutral Drainage (MEND) program for their effectiveness in preventing and controlling acid generation in sulphidic mill tailings. A critical parameter for predicting the performance of these covers is the diffusion coefficient of gaseous oxygen in the cover materials. Laboratory experiments conducted to determine the effective diffusion coefficient of a candidate cover material, a glacial till from an active mine site, are described. The diffusion coefficient is determined by fitting a semianalytic solution of the one‐dimensional, transient diffusion equation to experimental gaseous oxygen concentration versus time graphs. Effective diffusion coefficients determined at high water saturations (85%–95%) were of the order of $8\times {10}^{-8}{m}^2/s$. The diffusion coefficients decreased with increase in water saturation as a result of the low diffusivity of gaseous oxygen in water relative to that in air and the low solubility of oxygen in water. Placement of soil covers in high saturation conditions would ensure that the flux of oxygen into tailings underneath such covers is low, resulting in low acid flux. This is confirmed by combined laboratory, field, and modeling studies.

The cohesion intercept in the Coulomb shear‐strength equation has a significant influence on the location of the slip surface and the factor of safety. The cohesion intercept results from a linear approximation of a segment of a nonlinear shear strength against effective normal stress relationship. Shear strength on a slip surface, at the instant of a global instability, may range from residual strength to peak strength for stiff clays, and from large strain strength to peak strength for soft clays. Peak strength controls local development of slip surface, but it may not be available during global failure. The critical slip surface for an initial slide is determined using the peak shear strength. However, a mobilized strength equal to or less than the peak strength is used to define the factor of safety. Effective stress‐stability analysis of slope failures has resulted in a reduction factor to the peak strength in order to obtain the mobilized strength for first time slides. For over 60 slope failures in soft and stiff clays, the values of $c\prime$ (mob) are in the range of 0–26 kPa as compared to 1–150 kPa for $c\prime$ of the clays involved in the failures.

A general frequency‐domain solution for electrical response of two‐phase dilute (high porosity) soil is presented. Tensorial character of the response in terms of dielectric constants as well as the resistivities of the constituents is illustrated. For transversely isotropic soils a single measurement at 55° to the axis of symmetry can predict scalar parameters such as porosity of soils or conductivity and dielectric constant of pore fluid or particles. Under special cases the results reduce to some well‐known relationships. Important characteristics of the dielectric formation factor are highlighted. Effects of particle concentrations on the electric response are introduced. The semitheoretical solutions taking into account the effects of particle concentrations do not deviate very much from the solution based on dilute particle arrangement. Beneficial effects of clay‐water interaction on dielectric response are discussed. Applicability of the theory is examined using experimental data.

Results presented in this paper represent the first part of research produced by the Verification of Liquefaction Analysis by Centrifuge Studies (VELACS), a cooperative research effort involving eight universities. Ultimately, the objective of the project is to perform a series of dynamic centrifuge model tests on a variety of different soil models to study the mechanisms of liquefaction‐induced failure and to use the results of these tests to verify various numerical procedures used in the analysis of liquefaction problems. However, prior to completing this final part of the project, a series of model tests was run by each of the eight universities to evaluate the dependence of centrifuge test results on the testing apparatus and test team; these results are presented here. Each university performed one model test using a standard model box; soil‐ and test‐preparation technique; soil configuration; and input earthquake motion. Model accelerations, pore‐water pressures, and surface settlements were measured during the eight tests and are compared in this paper. The test results help to define a general mechanism of liquefaction and show that similar results can be obtained when testing standard models at different centrifuge facilities. Although some scatter was observed, the results are sufficiently close to endorse their use in analysis validation exercises.

An earth‐reinforced retaining wall utilizing geogrids with full‐height precast concrete wall facing is instrumented. Measurements include movements of wall faces, lateral earth pressure, vertical stress in the soil mass, strains in the soil mass, and strains along the geogrids. A comparison is made between observed behavior and design assumptions and calculations. Based on this comparison, the following statements can be made: (1) Computation of maximum tension in the geogrids using the standard design procedure is in general satisfactory; (2) a part of the lateral earth pressure is transferred to the full‐height concrete facing, which is not considered in the design; (3) the distribution of vertical stress measured in the reinforced soil mass is nonlinear with the lowest value at the wall facing and this is contrary to the linear distribution assumed in the design calculations.