A study of the effect of the overconsolidation ratio (OCR) on the cyclic shear modulus degradation of clay is presented. The research is based on a series of strain‐controlled, constant‐volume, cyclic, simple‐shear tests conducted on samples of an offshore Venezuelan clay consolidated to $\mathrm{OCR}=1\text{,}$ 2, and 4. The modulus degradation with number of cycles is successfully modeled for different OCR's using an expression applied previously to normally consolidated clays. The rate of cyclic modulus degradation decreases with increased OCR, and the dynamic stress‐strain backbone curves can be modeled by an extension of the SHANSEP method originally suggested for normalizing static stress‐strain curves. A chart is also developed for normally consolidated marine clays from Venezuela, California, and Alaska, which indicates that the modulus degradation rate parameter t, corresponding to a given cyclic strain, is similar for similar clays, with t decreasing as the plasticity of the clay increases. Also, a comparison between values of t obtained from simple shear and triaxial tests on one of the clays shows that these different test types can be compared at an equal value of the increment of deviatoric strain trajectory for one cycle. This suggests a way to apply the modulus degradation model presented in this study to the analysis of 3‐D cyclic loading situations using the incremental theory of plasticity.

Expansive reactions between lime and sulfate‐bearing clay soils have attracted little attention until relatively recently. Lime treatment of Stewart Avenue in Las Vegas, Nevada, has induced heave in excess of 12 in. Heaved areas are found to contain abundant thaumasite, a complex calcium‐silicate‐hydroxide‐sulfate‐carbonate‐hydrate mineral. Thaumasite forms a solid solution series with ettringite, a calciumaluminum‐hydroxide‐sulfate‐hydrate mineral. In the presence of aluminum, ettringite forms first and is replaced by thaumasite only at temperatures below 15 °C. The mechanism of heave is a complex function of available water, the percentage of soil clay, and ion mobility. Only the long‐term pozzolanic chemistry of normal lime‐soil reactions is disrupted. Cation exchange, agglomeration, and carbonation are unaffected. With the present state of knowledge, lime‐induced heave is difficult to predict for all but most obvious conditions.

The design of spread foundations for uplift loads is based primarily on capacity considerations, largely because there has been only a limited effort to characterize the load‐displacement response of these foundations. This paper examines the results of 75 full‐scale field tests and synthesizes the results in a convenient design procedure that incorporates estimated displacements. The effects of soil type (granular versus cohesive) and foundation type (steel grillage versus concrete slab or steel plate) are investigated, and it is found that: (1) Granular soils lead to a slightly stiffer response than cohesive soils in the initial portion of the load‐displacement curve; and (2) slab or plate foundations lead to slightly stiffer response than grillages for granular soils only. The type of foundation has little influence for cohesive soils, and for practical purposes, a single generalized load‐displacement relationship can be used to represent the available data for all four cases at the 95% confidence level.

The physico‐chemical processes of advection, dispersion, adsorption, and degradation that control pollutant transport processes in groundwater are described. Dimensional analysis is presented, and the scaling requirements for centrifuge modeling of these processes is developed. The validity of these scaling laws is examined by conducting modeling of models tests using several types of soils in idealized models of one‐dimensional flow situations. The importance of scaling gravity (by using a centrifuge) is highlighted. The centrifuge permits simulation of prototype stress levels and thus makes it possible to obtain identical soil properties such as permeability in a small‐scale model as compared to a full‐scale soil deposit. Simulation of capillary effects and a phreatic surface is also possible in a centrifuge model, but not in a 1‐g scale model. It is concluded that the scaling laws are valid for adsorption and advection in the reported model tests, but in coarse‐grained soils where the Peclet number is often greater than one, the dispersion process cannot be directly scaled from model to prototype. Even if direct scaling is not possible, the centrifuge is a useful tool for providing data to test or verify numerical models, since full‐scale test data are not abundant, and the full‐scale boundary and site conditions are poorly defined.

A method is proposed for evaluating the overconsolidation ratio in clays based on the distribution of dynamic pore pressure around a penetrating cone. For this purpose the pore-pressure measurements at or on the tip and at the base of the tip are normalized with respect to the hydrostatic pore pressure. The difference between the two normalized values is shown to correlate well with changes in the overconsolidation ratio. The conclusions are applicable to depths of about 30 m with water table near ground surface. Results obtained from various North and South American clays are evaluated resulting in a linear relationship between a defined pore pressure parameter and OCR. It would appear that this relationship can be applied to clays in general. However, the relationship may be dependent on the sensitivity of the soil. The proposed relationship can be considered appliable for overconsolidation ratios up to 10–15. At higher OCRs the effect of fissuring appears to modify the drainage conditions of the test, possibly producing a lower pore pressure parameter than expected, resulting in poor agreement with the proposed relationship.

Analysis and mathematical solutions are presented for a torsionally loaded pile embedded in two-layered soil deposit assuming elastic behavior. Soil shear modulus is assumed to be constant in each layer or to vary linearly with depth. Numerical results are obtained for practical range of parameters and nondimensional charts are presented for design purposes