A method for the internal design of reinforced soil walls based on working stresses is developed and evaluated using measurements from five full‐scale structures containing a range of reinforcement types. It is shown that, in general, the stiffer the reinforcement system and the higher the stresses induced during compaction, the higher are the tensile stresses that must be resisted by the reinforcements. Unique features of this method, compared to currently used reinforced soil wall design methods, are that it can be applied to all types of reinforcement systems, reinforcement and soil stiffness properties are considered, and backfill compaction stresses are taken explicitly into account. The method can be applied either analytically or using design charts. A design example is included.

Oil‐shale solid wastes are evaluated for use as soil stabilizers. A laboratory study consisted of the following tests on compacted samples of soil treated with water and spent oil shale: unconfined compressive strength, moisture‐density relationships, wet‐dry and freeze‐thaw durability, and resilient modulus. Significant increases in strength, durability, and resilient modulus were obtained by treating a silty sand with combusted western oil shale. Moderate increases in durability and resilient modulus were obtained by treating a highly plastic clay with combusted western oil shale. Solid waste from eastern oil shale appears to be feasible for soil stabilization only if limestone is added during combustion. Testing methods, results, and recommendations for mix design of spent shale‐stabilized pavement subgrades are presented and the mechanisms of spent‐shale cementation are discussed.

The increasing use of polymeric geogrids in reinforced soil walls and steep slopes warrants special attention to all details including their anchorage behavior. Because of the open structural nature of geogrids, their performance is different from other sheet‐like reinforcing materials such as metallic strips and geotextiles. They derive their anchorage capacity through both friction and bearing resistances. This paper focuses on the structural behavior of geogrids under a pullout loading condition. An experimental investigation is conducted using three different geogrids tested at three different lengths. The load‐displacement response at different locations along the geogrid is monitored during pullout. The experimental results are compared with predictions using a previously published finite‐element model simulating soil‐geogrid interaction and taking into account the deformation of the geogrid structure. Tension in the geogrid, as well as friction and bearing components of resistance, are presented in relation to geogrid length, pullout load magnitude, and distance from the clamped end of the geogrid. Factors such as the load‐extension behavior of ribs in the pullout load direction and the flexibility of ribs in the perpendicular direction as well as their ability to transfer the load through the rib junctions are shown to greatly influence the overall behavior. The results emphasize the fact that the success of a geogrid in fulfilling its anchorage role is directly related to its structural composition and material specific characteristics.

A model for the analysis of pile axial response to transient dynamic loading and to harmonic loading is presented, allowing for nonlinear behavior of the soil adjacent to the pile, energy dissipation through different types of damping, and the loading rate dependency of the soil resistance. The approach is used to establish equivalent linear stiffness and damping parameters of single piles as well as dynamic interaction factors for approximate nonlinear analysis of pile groups. The applicability of these parameters to the pile‐group analysis was examined, and a reasonable agreement with the direct analysis was found. The superposition technique may be used to analyze the response of small pile groups. Also, the dynamic stiffness of pile groups is greatly affected by both the nonlinear behavior of the soil and the slippage between the pile and soil. For a basic range of soil and pile parameters, equivalent linear stiffness and damping parameters of single piles and interaction factors for approximate nonlinear analysis are provided.

Increasing offshore construction activities in areas where marine sediments contain gas (either in dissolved or free form) have generated an interest in developing in situ test equipment capable of detecting and quantifying the amount of in situ gases (η‐profiling). This is important since: (1) Failure to detect gas pockets ahead of the drill bit during soil investigation or drilling operations may result in gas blowouts, and, consequently, life and financial losses; and (2) if the amount of gas is not correctly quantified for use in advanced laboratory testing of gassy soil specimens, misleading design parameters may be established. This paper introduces a new in situ test device, referred to as the BAT probe, which is used to sample in situ pore water/gas to quantify the amount of gas in the soil (η‐profiling) and to predict the presence of gas pockets ahead of the drill bit. The results from a laboratory verification test program and several offshore soil investigation projects are presented and discussed.

Gas in solution in the pore water or in its free form is found in many marine sediments around the world. The presence of gas may influence and alter the properties of the host soil, and could, in some cases, jeopardize the stability of foundations of marine structures. The outcome of a pilot laboratory study on the effects of gas on the undrained static and cyclic strength of sand is presented in this paper. The test results indicate that the presence of gas may strongly influence the undrained strength of sand. The extent of the effect is, among other things, a function of the gas type, the amount of gas, and the pore pressure level.

Results from four centrifuge model tests are presented. Three of the model tests involve layered soil deposits subject to base shaking; one model test involves a uniform soil deposit of sand subject to base shaking. The layered soil models consisted of fine sand overlain by a layer of relatively impermeable silica flour (silt). Pore‐water pressures, accelerations, and settlements were measured during all four tests. Results from the model tests involving layered soils suggest that during liquefaction a water interlayer or very loose zone of soil may develop at the sand‐silt interface due to the difference in permeabilities. In each layered model test, boils were observed on the surface of the silt layer. These boils were concentrated in the thinnest zones of the overlying silt layer and provided a vent for the excess pore‐water pressure generated in the fine sand.

It is generally perceived that roughened high‐density polyethylene (HDPE) has superior interface frictional properties, when in contact with any type of granular material, compared to smooth HDPE. Large‐scale direct shear interface test results are presented that indicate that this is not always the case and that the shear strength of finer‐grained materials may be better mobilized by the currently available roughened HDPE than by coarser‐grained materials. Based upon a limited number of tests, there appears to be a direct relation between soil composition, depth of texturing, and the amount of shear strength mobilized during shearing. This study indicates that the ratio of D80 of the granular material to the height of texturing (h_text) of the roughened HDPE may be used to determine how much of a materials shear strength may be mobilized at the interface. The results of this testing suggest the importance of testing all interfaces when performing analysis and design for geosynthetic liners and covers.