Soil mechanics principles can be successfully applied to many of the problems encountered in underground mining. A few typical problems are described, and the application of soil mechanics to their solution is indicated. The topics considered include: (1) The design and properties of stiff fill materials for the support of underground excavations; (2) stress distribution within the fill contained by an inclined underground excavation; (3) the design of water retaining underground plugs; and (4) the design of behavior of steel‐reinforced walls of granular material used to provide roof support in shallow coal mines.

A new concept, effective confining contact stress (product of porosity and effective confining stress), used to analyze the mechanism of shear failure in granular materials with special reference to the reduction in effective angle of shearing resistance with increases in confining stress under triaxial compressive stress. Steel balls and sands from borehole, quarry, and river are studied. The results of the tests, which include unusually high stresses, show direct dependence of the angle of shearing resistance on effective confining contact stress within the dilative range regardless of the drainage condition and extent of particle crushing in the tests. This makes possible the formulation of a method by which the effective angle of shearing resistance of a material at any preshear porosity and confining stress can be estimated from the results of a limited number of drained tests within the dilative range. The physical significance of the dependence of shear strength on the new parameter is analyzed.

Tests were performed on dense and loose sand in a glass‐walled fault test box to investigate the shapes and locations of failure surfaces that may occur in alluvium overlying active dip‐slip faults. The experimental procedure is reviewed and the results of the tests with reverse and with normal movements along the bedrock faults are presented. Based on the experimental results, a simple model is developed to predict the shapes and locations of failure surfaces in the soil. These are determined as a function of the depth of the soil, the angle of dilation for the soil, and the dip angle of the fault. The conditions for development of a graben structure, as observed during normal movement on the bedrock fault, are also determined. The emphasis of the study is on the mechanics of deformation and failure in cohesionless soil above dip‐slip faults in relation to principles of soil mechanics. The simple model is also evaluated in relation to real field conditions.

The shapes and locations of failure surfaces in alluvium overlying active dip‐slip faults are studied on the basis of experiments performed in a fault test box. A simple model for predicting primary and secondary failure surfaces in the alluvium caused by unidirectional movement on the bedrock fault is reviewed. This model is employed to evaluate additional failure surfaces produced by fault movement in the opposite direction and subsequent to the initial movement. The shapes and locations of these latter failure surfaces are almost unaffected by the presence of failure surfaces caused by the initial fault movement. Ground surface expressions in alluvium associated with movements on dip‐slip faults are summarized. Three field cases are reviewed and related to the experimental observations and the proposed simple model. This model is used to predict shapes and locations of failure surfaces in alluvium overlying dip‐slip faults. Model predictions compare favorably with observations from the field.

An effective stress method is presented for analysis of seismic response and liquefaction of horizontally layered saturated sand deposits, based on solution of the fully coupled equations for the granular solid and the pore fluid. A new material model for hysteretic behavior of sands and a new effective stress path rule are presented. The shear modulus reduction and damping of the proposed model are compared with other experimentally based relations. The proposed effective stress analysis method is used to simulate shaking table tests, with results in reasonably good agreement with experimental results. The proposed method of analysis is compared with a number of other well‐known methods.

The effective stress method of analysis described in a comparison paper is used to study the effect of various factors on the response and the liquefaction potential of saturated sands. Through a number of analyses, a comparison is made between the results of total stress analysis and effective stress analysis. Analyses are performed to study the effects of the earthquake type, peak base acceleration, depth of water table and coefficient of permeability. The influence of these factors on the pore pressure build up, characteristics of ground surface response and the liquefaction potential are studied.