The results of model tests of 18 ground anchors vertically buried in sand are described in this paper. Also described are tests on half‐section model anchors which were tested to observe movement and behavior during uplift loading of the soil surrounding the anchors. Comparison tests were done to determine the influence of factors such as diameter, fixed anchor length, and buried depth on the uplift capacity of anchors. Two types of failures, deep and shallow, were observed in the tests. The tests showed that top resistance and skin resistance did not occur simultaneously. Peak skin resistance required very little anchor movement, while peak top resistance required substantially more movement. It is concluded that equations currently used to estimate anchor capacity by adding peak skin and top resistance should be modified. Based on the results of the model tests, and confirmed by field tests, an equation was developed for estimating uplift capacity and displacement of anchors.

This article deals with the prediction of the response to monotonic axial loading of single piles in various soil conditions. A 98‐pile load test data base was obtained from the Mississippi State Highway Department and was used to evaluate 13 methods designed to predict the ultimate load of a pile and five methods designed to predict the settlement of a pile. The methods include SPTA/$S_u$ methods, cone penetrometer methods, a pressuremeter method, and a dynamic formula method. The accuracy and precision of each method is quantified statistically, and a risk analysis is performed in order to properly assess the factor of safety. A cost analysis is also performed in order to find the factor of safety that will minimize the cost of construction plus the cost of a potential failure.

A study of the dynamic impedances for radially inhomogeneous, infinite viscoelastic layers with a circular hole, and for piles embedded in a medium represented by such layers is made. Systems in vertical and torsional modes of vibration are examined considering both a discontinuous variation in shear modulus and an exponentially increasing, continuous variation. The results are evaluated over wide ranges of the parameters involved and compared with those obtained for a homogeneous layer. In addition, the harmonic response of strip foundations supported at the surface of a vertically inhomogeneous viscoelastic half‐space is examined, and it is shown that within the framework of a previously proposed approximation, the impedances of such foundations for both horizontal and vertical modes of vibration may be deduced from those obtained for the vertically excited, radially inhomogeneous layer.

Materially objective, rate‐type constitutive relations are presented for creeping soil. The soil is treated either as a non‐Newtonian viscous fluid or a saturated mixture of an inviscid interstitial fluid and a non‐Newtonian viscous fluid matrix. In the latter case, the effective stress is additively decomposed into a quasi‐elastic and a viscous component; the former relates the void ratio with the spherical stress and accounts for consolidation, the latter describes rate dependent deformations. Starting from stress‐stretching relations of a Reiner‐Rivlin fluid and by postulating that the stretching can only depend on nonlinear stress quantities via the second stress deviator invariant, the most general isotropic constitutive relations are deduced. Mathematical expressions which are postulated for the free phenomenological functions are calibrated with the aid of laboratory and field data. The fits that are obtained for specimens subjected to triaxial and shear tests, as well as in situ tests from Swiss landslides, prove satisfactory reproduction of the observed creep behavior.

Analysis of the response of pile foundations to lateral loads requires accurate characterization of the behavior of the pile and the soil surrounding the pile. The common assumption of pile linearity in bending may not be valid in many cases. A model for representing nonlinear pile bending behavior in the analysis of laterally loaded piles is introduced. The ability of the model to predict observed behavior is illustrated by application of the model to a lateral load test case history.