The behavior of both flexible and rigid shafts socketed into rock and subjected to lateral loads and moments is studied. Parametric solutions for the load‐displacement relations are generated using the finite element technique. Based on these solutions, simple, approximate, closed‐form equations are developed to describe the response for the full range of loading conditions, material parameters, and socket‐rock mass stiffnesses encountered in practice. These results are in close agreement with available solutions for the limiting cases of flexible and rigid shafts. The solutions give horizontal groundline displacements and rotations and can incorporate an overlying soil layer. The problem of assessing the lateral load capacity of rock‐socketed foundations is also addressed, and a method of analysis to predict this capacity is suggested. The application of the theory, in the form of back‐analysis, to a single case involving the field loading of a pair of rock‐socketed shafts is also described.

Membrane compliance significantly increases the liquefaction resistance of gravelly soils determined by undrained, cyclic triaxial tests. The mechanisms of membrane compliance are discussed in this paper. The liquefaction resistance of 2.8‐in. (71‐mm) and 12‐in. (305‐mm) diameter triaxial gravel specimens are presented in this paper for two conditions: (1) A typical membrane compliance system; and (2) a very low compliance system. The low‐compliance system is created by sluicing the gravel specimens with sand so that the peripheral specimen voids are filled, significantly reducing penetration during consolidation. The liquefaction resistance of sluiced specimens is found to be about 60%‐65% of unsluiced specimen values. Residual pore pressure ratios of 100% develop in sluiced specimens for values of cyclic stress ratio and number of stress cycles causing about 12% residual pore pressure ratio in unsluiced specimens. It is concluded that tests performed on sluiced gravel specimens significantly reduce membrane compliance and provide a more accurate assessment of the noncompliant liquefaction resistance of gravel specimens.

Large permanent displacements of anchored retaining walls such as quay walls, sheet‐pile walls, and bulkheads are often reported in the literature after moderate to strong seismic activity. In most cases, liquefaction of the soil is cited as the reason for the large displacement or failures. In this paper, we examine an alternative mechanism, generated by inertial forces, which triggers large displacements of anchored retaining walls during moderate to strong earthquakes. Through this mechanism, we investigate whether substantial wall displacements or failures precede liquefaction. A limit equilibrium analysis, using the Mononobe‐Okabe seismic earth pressure equations, is performed to determine whether anchor failures lead to the general failure of anchored retaining walls during seismic events. Results of shaking‐table tests on aluminum walls with a dry cohesionless soil as the backfill confirm the analytical methodology. Based on the limit analysis, a balanced seismic design concept for anchored retaining walls is presented. We find that the balanced seismic design enhances the seismic resistance of anchored retaining walls at little additional expense. We use a typical design example to compare the balanced design procedure with current design practices.

A simple approach for nonassociative elastoplastic modeling of mechanical behavior of soils is presented in this paper. The distinctive features of this model are: (1) Disparate mechanisms for volumetric and distortional yielding; (2) plastic flow functions similar to those employed in the original cam‐clay models; (3) yield stresses given by single state variables; and (4) hardening moduli controlled by the evolution of a state variable. The capability of the model in its present form has been assessed against common triaxial (monotonic loading) test results obtained from published sources. Many complex characteristics of granular soils such as mean stress and path‐dependent dilatancy, strain‐hardening and strain‐softening responses in drained shear, and density‐dependent undrained shear responses (complete liquefaction as well as cyclic mobility) are remarkably well reproduced by this approach.

The success of an anchored geosynthetic system depends in large part on the ability of the system to remain tensioned after installation. For pinned‐anchor and spring‐steel collar connectors, the pullout stiffness of the anchor, along with the geosynthetic‐soil system response during unloading, controls the post‐installation fabric tension. Since anchors are typically long, slender driven reinforcing rods, both elastic extension and rigid body translation must be accounted for in determining anchor pullout stiffness. The interface shear strength between soil and anchors mobilizes linearly with relative displacement up to a critical displacement, beyond which it remains constant at the maximum interface shear strength. Solutions for the pullout problem in cohesionless soil are developed, and examples illustrate how pullout stiffness requirements, and therefore anchor lengths, may be determined for spring‐steel collar connectors. A threaded‐anchor‐and‐nut connection, although more difficult to install, is the preferred connector since the loads transferred to the soil are only limited by the maximum pullout resistance of the anchor, not the anchor pullout stiffness.

A new method to evaluate static strength and deformation behavior of gravelly soils containing particles too large to be tested with conventional laboratory equipment is presented. This new matrix method is based on the assumption that large particles floating in a matrix of finer‐grained material do not significantly affect the strength and deformation characteristics of the mixture. Therefore, the behavior of a prototype soil containing oversized particles can be modeled by testing the matrix portion alone, provided the model specimen is prepared at the density that exists within the prototype soil away from the oversized particles. A testing program designed to validate the matrix modeling method is described. Results of consolidated‐drained triaxial (CDTX) tests performed on prototype and model specimens are presented. CDTX peak shear strengths for the prototype and model soils are found to be almost identical. Fully softened strengths for the prototype and model specimens vary by no more than 15%. The stress‐strain and the volumetric strain‐axial strain behavior of the prototype and model soils are very similar up to the peak shear stress.

The response of an elastic foundation, such as settlement, can generally be obtained by integrating the product of the influence factor and the distributed load over the entire foundation. The exact evaluation of this double integral is usually very involved, especially for arbitrarily shaped foundations. In the paper, a very simple method is developed for obtaining the elastic responses of soils and rocks using the computer package MathCAD and Green's theorem in calculus. Initially, the double integral is transformed into a line integral by invoking Green's theorem. The line integral can then be evaluated very conveniently using the built-in procedure in MathCAD for numerical integration. The proposed method can be applied to an arbitrarily loaded area with an arbitrary stress distribution and can be programmed very easily using MathCAD. Examples will be given to illustrate the use and accuracy of the proposed method.

In the technical note, a two-dimensional mathematical model for piping under a dam on a granular material is reported. No details of the calculation are given, but the results are communicated. The key feature of the model is the treatment of a piping channel, thus incorporating and unifying apparently conflicting hypotheses made in the past by Lane and Koshla. The result is a map of steady-state equilibrium situations that are possible for the length of the piping channel under the dam as a function of the water-level difference on both sides of the dam and the particle grain size. The latter parameter arises because of the necessary treatment of the stability of the channel walls. The results show that stable states are possible as long as the piping channel does not exceed half the length of the structure. A formula linking the relevant parameters to obtain a necessary condition for equilibrium is presented. Implications for model tests and centrifuge tests are discussed.

Continuous flight auger (CFA) piles are a popular and effective technology for low-vibration and low-noise applications in inner urban areas. This technical note describes the writers' observations and comments on the loss of ground related to CFA pile installation during construction of the deep foundation for a 52-story apartment building in the city of New York. In order to reduce the loss of ground during CFA pile installation, several technical procedures are formulated, field tested, and adopted. However, the potential for the ground loss and subsequent movement of adjacent structures exists throughout the duration of CFA pile installation and should be evaluated by a site-specific investigation.