Laboratory tests indicate that a one‐dimensional advective‐dispersive transport model for reactive solutes provides reasonable estimates of the breakthrough of low‐concentration organic contaminants in saturated fine‐grained earthen barriers. Based upon this transport model, a design/analysis methodology and respective guidelines are developed for earthen barriers used in waste disposal applications. The limitations and restrictions of the model are discussed and fundamental variables affecting the transport are parametrically analyzed. Transport of low‐concentration trichloroethylene at a selected study site was selected for illustrating the presented procedure.

A new elastoplastic model has been developed for predicting the stress path, the stress/strain response, and the shear strength of soils under cyclic loading. The model utilizes multiyield surfaces and a combination of isotropic and kinematic hardening. The model is similar to that of Prevost (1978) but introduces several new concepts. A theoretical expression is derived for the permanent volumetric strain, which occurs during undrained cyclic loading, that reflects the anisotropic behavior of the soil. Theoretical derivations are also presented to show that during undrained cyclic loading the elastic bulk modulus is constant and that the Skempton pore‐water pressure coefficient, associated with each yield surface, does not vary from its initial value. These relationships considerably simplify the task of predicting the response of the soils under cyclic loading. Experimental verification of the model predictions for the stress path, stress/strain curve, and shear strength of a very loose sand are presented, together with the model predictions for a kaolin clay using published data.

Mat foundation design requires an analysis of the mat when subjected to unsupported regions due to swelling or shrinkage of expansive soils. A study was conducted to investigate simple rational methods for calculating the active zone depth (z) and from it the edge moisture penetration distance $\left(L_m\right)$ in expansive soils. Analysis of soil moisture diffusion assuming a periodic variation in surface‐soil suction indicated that z can be a function of the maximum suction change imposed, minimum suction change considered significant, climate frequency, and field diffusion coefficient. The $L_m$ may be given by $z-D$ where D is the depth of the foundation or perimeter stiffening beam below ground surface. Data required to evaluate z and $L_m$ were obtained from field observations made during an 18‐month study on airport pavements on expansive soils. These climatic parameters may also be used in design of mat foundations supporting structures.

Freshly consolidated or densified clean sands exhibit a substantial increase in stiffness under drained aging conditions. Laboratory measurements of dynamic shear modulus after primary consolidation and field measurements of penetration resistance after ground densification by blasting, vibrocompaction, or dynamic compaction, in clean sands show a significant increase with time. A possible mechanism for this time effect in clean sands is the continued rearrangement of sand particles during secondary compression. Improved frictional resistance to deformation develops with time with a gradual increase in interlocking of particle surface roughness and increased geometrical particle interference through more efficient packing. Empirical equations are proposed that result in satisfactory predictions of the postprimary consolidation shear modulus and of postdensificatibn cone‐penetration resistance. The equation for the time‐dependent cone resistance includes the assumption of a decrease in compressibility and an increase in effective horizontal stress during secondary compression. In the absence of continued cone‐penetration testing subsequent to compaction, the proposed equation may be used to extrapolate from measurements that are carried out immediately after ground modification.

Laboratory resonant‐column and torsional shear tests are performed to determine the dynamic response (i.e., shear modulus and damping) of sands reinforced with discrete, randomly distributed fibers. The effect of fiber inclusion is evaluated as a function of shearing‐strain amplitude, confining stress, prestrain, number of cycles, fiber content, aspect ratio, and modulus. The dynamic modulus increases with increasing fiber aspect ratio, modulus, and with increasing fiber content to a limiting weight fraction. The presence of fibers reduces prestrain effects often observed in unreinforced sands. The increase in dynamic modulus of fiber‐reinforced sand is decidedly more pronounced at high shearing‐strain amplitudes. The maximum percentage increase in modulus as a result of fiber inclusions occurred over a narrow range of confining stresses from 3 to 10 psi (21 to 48 kPa). Damping was less affected by the inclusion of fibers than shear modulus. The dynamic response of sands reinforced with vertically oriented fibers is very similar to that of randomly distributed fibers.

A field study was made for evaluation of variability in degree of compaction of structural fills. Multiple runs of field‐density tests were performed at three sites by nine geotechnical engineering firms in San Diego, California. The tests were run after the geotechnical engineer had tested and approved each site as having met the 90% relative compaction requirement. All tests at each site were performed at the same time and at the same elevation in close proximity to each other. A statistical analysis of the results indicated a significant scatter in percent compaction data: The range of variations, expressed as a percentage of the mean value, were about 17% for a uniform silty sand fill, 15% for a silty clay fill, and 26% for a gravelly to cobbly sand fill. This amount of variability in relative compaction is greater than that generally found in embankment dams. This is partly because the standards of practice for mass grading of structural fills are less rigorous than for dams, and partly because of inadequate or imperfect fill‐control procedures.

A design approach is presented to analyze laterally loaded piles embedded in layered frozen soil. The design approach makes use of a commercially available computer solution that uses p‐y curves to model soil and pile interaction. Shear strength and strain criteria for both ice‐rich and ice‐poor soil are presented for use in constructing p‐y curves. Published pile load test results and deflections calculated using the design approach are compared. Two Prudhoe Bay, Alaska loading cases are analyzed, and calculated deflections and moments are presented.

A closed‐form solution for determining the development of tension in soil reinforcements is incorporated in a rigid‐plastic soil model. The model accounts for the plastic work to deform the soil and the elastic work to deform the reinforcements in tension and bending. The model is used to evaluate experimental results obtained in large‐scale direct‐shear tests. The results show that the mobilization of tension in the reinforcements is a function of the reinforcement properties and the deformation characteristics of the reinforced soil. The reinforcement properties affect the width of the shear zone and the increase in the strength of the reinforced soil is not linearly proportional to the reinforcement concentration. The contribution of reinforcement tensile stresses to the increased strength of the reinforced soil is as much as one order of magnitude greater than the bending stresses. Thus, the use of limit equilibrium methods for analysis of reinforced structures, ignoring the bending moment contribution, is recommended.