This study describes the performance of a full‐scale embankment raised on a soft marine clay, stabilized with vertical band drains in Malaysia. The finite element code CRISP, which is based on critical‐state soil mechanics, has been employed to investigate the performance of the embankment and the underlying soft clay. Predictions of the excess pore pressures and both vertical and lateral displacements are made and compared with field observations. The limited use of closed‐form solutions for the prediction of settlements at the line of symmetry of the embankment is also discussed. The effectiveness of the prefabricated drains has been evaluated according to the rate of excess‐pore‐pressure dissipation at the soil‐drain interface. The numerical approach is based on a coupled consolidation analysis rather than on a conventional, purely undrained analysis. The numerical analysis reveals that for efficient vertical drains, the influence of smear and well resistance can be ignored. While the assumption of perfect drains may be acceptable in the long term, the short‐term settlements are governed by the drain efficiency.

Postearthquake deformations of the Wildlife site, Imperial Valley, Calif., following the 1987 Superstition Hills earthquake, have been interpreted by finite‐element deformation analyses. The analyses consider the stress redistribution and reconsolidation caused by the development of liquefaction. The stress redistribution analysis was conducted under fully undrained condition to consider the effects of strain‐softening behavior of liquefied materials. The reconsolidation analysis was conducted using Biot's theory to consider the effects of dissipation of excess pore‐water pressures. The results reveal that the delayed pore‐water pressure response and deformation may be due to the redistribution of stresses and pore‐water pressures.

The Luzon Earthquake of 1990 $(M_s=7.8)$ caused soil liquefaction in a widespread area that in turn caused crucial damage to various structures. After presenting an overview of the geotechnical aspects of the earthquake, this paper describes damage patterns of buildings in Dagupan City where fine to silty sands liquefied extensively. Also presented are geomorphological conditions, Standard Penetration Test (SPT) results, and shear wave velocity $\left(V_s\right)$ profiles determined by a Rayleigh wave method; and their relations to the building damage of the city. The buildings that suffered large settlement and tilting are found to be concentrated in the banks of active rivers and in the fills built on recently abandoned river channels. It is found that the currently available empirical correlations using SPT N‐value can well estimate the extent of liquefaction‐induced damage to buildings. The Rayleigh wave method used shows capability in determining cross sections of $V_s$ structure in the near surface soil.

An analysis of pile axial response to transient dynamic loading and to harmonic loading is presented allowing for nonlinear soil behavior, energy dissipation through radiation damping, soil hysteresis, and the loading rate dependency of the soil resistance. Also, the postpeak soil resistance is modeled for certain soil types, and the effect of neighboring piles is taken into account for piles in a group. The approach is used to analyze the pile response to harmonic forces, pile driving, and Statnamic loading and to establish the bearing capacity and load‐deflection curves; nonlinear dynamic interaction factors are also presented.

Two earlier papers by the writers, appearing in the preceding issue of the journal, presented an overview of the seismological and engineering aspects of the 1988 Armenia earthquake and examined building damage statistics contrasted to geologic and geotechnical soil profiles. Possible regions of appreciable soil amplification effects were identified in the cities of Leninakan and Kirovakan. The present paper and companion paper, in the same issue of the journal, present results from analytical soil amplification studies using actual soil profiles from Leninakan and Kirovakan, and investigate whether or not current state‐of‐practice methods could adequately explain the damage statistics and their local and geographical distribution in the two cities. The present paper deals with Leninakan, which is located in the center of a very wide flat valley, having a width‐to‐maximum‐soil‐thickness ratio of about 55. Results indicate that, when using proper laboratory and field measurements of soil properties, one‐dimensional soil amplification analyses can explain well not only the trends observed in the intensity and distribution of damage to buildings, but also observations made of response of various structures in Leninakan. The companion paper describes the one‐ and three‐dimensional soil amplification analyses and valley effects in Kirovakan and summarizes the overall conclusions drawn from this research related to soil effects during the Armenia earthquake.

There is substantial evidence that the city of Kirovakan, Armenia, despite its proximity (10 km) to the fault, experienced in general very small intensity of shaking during the 1988 earthquake. Moreover, the distribution of damage in the city was very nonuniform. In this paper, first, arguments are presented to show that seismological and geologic factors, relating to the generation and transmission of the seismic waves, could explain the unusually weak base excitation in Kirovakan. Then, the results of one‐dimensional (1D) wave‐propagation analysis, using soil profiles with field and laboratory measured parameters, are presented to explain the damage statistics in five zones into which the city was divided. 1D analyses of wave amplification in soil are found to provide adequate answers for zones where the underlying soils consist of less than 30 m dense gravelly sands and stiff clays. However, such analyses fail to explain the disproportionately large degree of damage observed only in one region, where soil profile constitutes a triangular sedimentary basin with maximum soil depth of about 150 m and width‐to‐depth ratio of about 5. A simplified three‐dimensional wave‐propagation analysis of the “valley” effects on ground‐surface motions, provides a better explanation of the observed damage.

A database is described that contains laboratory measurements of hydraulic conductivity and associated soil properties that were extracted from construction reports for compacted soil liners. The database contains measurements conducted on a wide variety of soils from 67 landfills in North America. The database was used to evaluate relationships between hydraulic conductivity, compositional factors, and compaction variables and to identify minimum values for soil properties that are likely to yield a geometric mean hydraulic conductivity $\le 1\times {10}^{-7}\mathrm{cm}/s$. A graphical analysis suggests that a geometric mean hydraulic conductivity$\le 1\times {10}^{-7}\mathrm{cm}/s$ can be achieved if the liquid limit ≥20, the plasticity index ≥7, the percent fines (<No. 200 sieve) ≥30%, and the percent clay (<2 μm) ≥15%. A multivariate regression equation was also developed that can be used to estimate the geometric mean hydraulic conductivity as a function of soil composition and compaction conditions.

The paper explores the use of discrete element simulations to model granular soil response to monotonic and cyclic loading. Two‐ and three‐dimensional random arrays of quartz spheres of various diameters are used that crudely represent rounded uniform quartz sand. Computer program CONBAL, developed by the writers from existing code TRUBAL, is used. All simulated granular specimens are first isotropically consolidated, and are then subjected to monotonic drained loading or constant volume (undrained) cyclic “simple shear” simulations. The monotonic results exhibit similar pressure‐dependent shear strength and dilation behavior to that found in actual sands, but with the simulated specimens being stiffer and failing at a smaller strain. The simulated cyclic loading results closely resemble the “pore water pressure” buildup to initial liquefaction, hysteresis loop formation and degradation, “banana loop” shapes, and lines of phase transformation observed in sand experiments. The effect of intergranular friction coefficient ${\mu }_s=\tan {\phi }_u$ and particle rotation on the results of simulated material is also studied, and they are found to be very important.

Stability postulates by Drucker and by Hill are applicable to solid metal. When applied to granular material exhibiting nonassociated flow, these concepts of stability imply that the material may be unstable when exposed to certain stress paths inside the failure surface. Series of triaxial tests on fully saturated and partly saturated specimens of sand have previously been performed under drained and undrained conditions to study the regions of stable and unstable behavior. The stability postulates by Drucker and by Hill do not capture the conditions for stable and unstable behavior of granular materials. Granular materials may become unstable if the state of stress is located above the instability line for the material. Presented here is a series of experiments conducted on loose sand that compresses during shear. In these tests the sand is allowed to creep over different periods of time resulting in movement of the yield surface. The influence of the new location of the yield surface on the static and cyclic instability of the sand is studied and discussed.

The hyperbolic stress‐strain model has been shown to be valid for modeling the nonlinear stress‐strain behavior of soils prior to failure in soil‐structure interaction analyses. However, guidelines for selecting hyperbolic stress‐strain parameters for silts have not been published to date. To fill this need, a series of isotropically consolidated‐drained and consolidated‐undrained triaxial tests were performed on freshly deposited, normally consolidated silts and clayey silts to provide guidance for selecting hyperbolic parameters for these materials. The effect of clay mineral content and dry unit weight on the hyperbolic parameters was investigated by reconstituting specimens at clay mineral contents of 0, 10, 20, 30, and 50% by dry weight and at standard Proctor relative compactions of 85, 90, 95, and 100%. At low clay mineral contents, the normally consolidated silt exhibited dilative shear behavior while a contractive behavior was observed at high clay mineral contents. The transition from dilative to contractive shear behavior is controlled by clay mineralogy. Due to the dilative behavior of the normally consolidated silt mixtures, failure criteria of maximum deviator stress and maximum pore‐water pressure were used to obtain the Mohr‐Coulomb shear strength parameters from the drained and undrained triaxial tests.

The calculation of stresses under rectangular footings with biaxial bending is carried out by solving the three‐equations system that sets up the load and soil stresses equilibrium. When a planar soil stresses distribution is assumed, and the area is in full compression, the just mentioned system is linear and its solution immediate. With increasing eccentricities, some corners of the footing can get detached from the soil, the system becoming nonlinear, and difficulties arise in its resolution. In the paper an analytical alternative to the numerical and graphical solutions is presented, which will lead to obtaining explicit solutions for these stresses and neutral axis location.

Theoretical relationships suggest that the hydraulic conductivity of compacted soils can be evaluated with electrical resistivity measurements. On the material scale, high resistivity may be indicative of low molding water content, high air‐filled porosity, or high sand or gravel content. On the liner scale, resistivity measurements may be useful for identifying desiccation cracking or poor interlift bonding. Methods exist for measuring the resistivity of compacted soils in the laboratory and on field liners. Further evaluation is warranted to fully assess the utility of resistivity measurements for evaluating soil liners.