Using a geotechnical viewpoint, this paper proposes a potential, partial solution to solve some of the problems posed by increasing amounts of certain types of sludgy industrial waste. The primary objective of this study is to examine the potential for burning various industrial wastes combined with lime, in certain proportions, to produce a by‐product having cementing characteristics similar to ordinary portland cement (OPC). It is found that the percentages of main cementitious compounds in this new cement‐like stabilizer are comparable to those of OPC. The by‐product also shows promise for use in stabilizing a loam soil. The contribution of ettringite to strength development is discussed. It is found that this new type of additive can be used to stabilize loam soil for subgrade purposes.

There are many sources of uncertainty involved in seismic safety evaluation of an embankment or an earth dam. Even when conservative assumptions and selections of parameters are made, there will always be a probability that performance of the dam during its lifetime may not be as predicted. To evaluate seismic risk of damage or failure of earth dams, a seismic risk analysis procedure is presented. The future occurrence of earthquakes is probabilistically described in terms of both intensity and number of cycles of ground motion (seismic hazard analysis). Furthermore, a probabilistic procedure for the calculation of permanent deformation of earth dams (seismic performance analysis) is presented, characterizing the seismic event in terms of acceleration, number of cycles, and predominant period of motion. The results of seismic hazard and seismic performance analyses are combined to yield the risk of seismic damage or failure of a dam (seismic risk analysis). An example case study is presented, illustrating the application of the procedures. A risk‐based seismic safety evaluation of an embankment or an earth dam can provide estimates of relative risks that are useful in design and decision analysis and can avoid compounding of conservatism.

A simple procedure for estimating earthquake‐induced permanent deformations of earth dams, embankments and slopes is presented. The analytical model is based on computed permanent deformations obtained by using Newmark's sliding‐block analysis and actual recorded acceleration time histories. The model incorporates the effect of earthquake magnitude through the use of equivalent uniform cycles of motion. Uncertainties in the model and the parameters used are accounted for through the use of modeling error theory. Normalized plots and a computer program are presented that provide the probability that the permanent deformation of a critical sliding mass will exceed a specified value. The results from this probabilistic procedure can be expressed in terms of damage probabilities in the form of a seismic performance analysis matrix. The use of a seismic performance analysis matrix in an overall seismic risk analysis for an earth dam, embankment or a slopes is described in a companion paper.

The transitional yielding approach offers a unique and smooth definition for loading, unloading, and reloading; further, it need not define a conjugate point. A generalized transitional yielding approach, with any desired number of limit surfaces, is proposed. These limit surfaces represent various degrees of the hierarchical material memory due to stress history. A new method for modeling nonassociative soil behavior is also proposed; it has the advantage of using exactly the same function for the yield surface and the plastic potential surface. Model prediction and experimental data are compared to illustrate the validity of the proposed approach.

Rectangular open or in‐filled trenches (wave barriers) are often used in engineering practice to reduce the ground vibrations caused by propagating surface (Rayleigh) waves of relatively small wavelengths. This paper presents simple design expressions for estimating the vibration screening effectiveness of rectangular wave barriers in homogeneous soil deposits. The design formulas are developed by conducting an extensive numerical investigation on the influence of various geometrical and material parameters on the vibration screening effectiveness of the barriers. An advanced direct Boundary Element Method (BEM) incorporating higher‐order isoparametric elements and a sophisticated self‐adaptive numerical integration scheme is used for this study. Dimensionless parameters that govern a barrier's performance are then identified, and models are developed taking these parameters into account in a simplified way. Through some comparisons with results from the rigorous BEM code and available experimental data, the applicability of the model is demonstrated. Some layered soil cases are also studied, and the important effects of layering on the performance of a trench as a wave barrier are presented.

A study on the influence of the plasticity index (PI) on the cyclic stress‐strain parameters of saturated soils needed for site‐response evaluations and seismic microzonation is presented. Ready‐to‐use charts are included, showing the effect of PI on the location of the modulus reduction curve $G/G_{\max }$ versus cyclic shear strain ${\gamma }_c\text{,}$ and on the material damping ratio λ versus ${\gamma }_c$ curve. The charts are based on experimental data from 16 publications encompassing normally and overconsolidated clays $(\mathrm{OCR}=1-15)\text{,}$ as well as sands. It is shown that PI is the main factor controlling $G/G_{\max }$ and λ for a wide variety of soils; if for a given ${\gamma }_c$ PI increases, $G/G_{\max }$ rises and λ is reduced. Similar evidence is presented showing the influence of PI on the rate of modulus degradation with the number of cycles in normally consolidated clays. It is concluded that soils with higher plasticity tend to have a more linear cyclic stress‐strain response at small strains and to degrade less at larger ${\gamma }_c$ than soils with a lower PI. Possible reasons for this behavior are discussed. A parametric study is presented showing the influence of the plasticity index on the seismic response of clay sites excited by the accelerations recorded on rock in Mexico City during the 1985 earthquake.

Tests are conducted on the filtration characteristics of the chimney drain and on the erodibility of the upstream clay blanket at Conner Run Dam. The test results are discussed and conclusions drawn regarding the potential of compacted clay to erode internally and on the validity of current filter criteria to prevent piping from occurring. The beneficial effects of fly ash in the reservoir to control piping of clay blankets is also evaluated.

Equipment for determining water content rapidly, accurately, and reliably is required to properly monitor the compaction of earth fills. Improper compaction control can result in structures with severe performance and maintenance problems. Water content determination in a conventional oven may require up to 24 hr. If 24 hr are required to determine that the water content of a layer is unacceptable, that layer may be buried under several feet of subsequently placed and compacted fill. This paper describes a microwave drying system developed to determine water content reliably and accurately in real time. The design of the system is based on continuously monitoring the weight change of a soil specimen subjected to microwave radiation. The system, its theory of operation, and its use are described briefly. Data are presented to show that microwave and conventional water contents usually correlate to within half a percentage point for a variety of soils. The microwave system has been satisfactorily used on two Corps of Engineers filed projects. Analysis of data from the projects is presented.

A slide in the upstream slope of California's San Luis Dam on September 4, 1981, was caused by a loss of strength in the stiff clay in the foundation beneath the slope. This loss in strength, which occurred over 14 years of the dam's operation, is not explainable in terms of commonly held views of the behavior of stiff clays. An investigation showed that the shear strength of the desiccated clay beneath the dam decreases very rapidly to the fully softened strength when the clay is soaked. When the clay is subjected to cyclic loading, as it was by cycles of reservoir filling and emptying, the strength of the clay decreases gradually from the fully softened strength to its residual value. These mechanisms of strength loss appear to have been responsible for the San Luis Dam slide, and should be considered in stability evaluations whenever stiff clays are subjected to wetting and cyclic variations in load.

A comparison is made of the experimental and theoretical values of bending moment, shear force, deflection, and pressure for a reinforced concrete box culvert measuring 1,200 by 1,200 mm (inside dimensions) by 9-m long and 75 mm (uniform) thick. Dry sand is used to backfill the culvert. Both the numerical and experimental results compare favorably, but the results differ appreciably from those considered for conventional analysis and design. Also, there is a substantial reduction in the midspan bending moments as compared with conventional analysis.

Existing models for one-dimensional compression of clays are reviewed. Only the recently proposed Hardin's model has potential for realistic prediction of one-dimensional compression behavior of clays over a wide stress range. A new, extended power-function model is also presented and compared with the published compression data and with the Hardin's model. Both models fit the experimental data for normally consolidated, as well as overconsolidated, samples. For normally consolidated samples, they properly account for the change of the one-dimensional compression behavior, in the low stress range, for different initial void ratios. Since each of the models has only three parameters, they present an attractive replacement for the existing models. Which of the models should be used in any practical application will depend on their relative performance. It is most likely that the choice will be based on the user's preference and not on the merit of the model itself.