Karl Terzaghi, a major contributor to progress in embankment dams, made significant contributions to the understanding of properties of rockfill and to the improvement of design of the concrete‐face rockfill dam. His contributions are noted and followed by a history of parallel development of earth core and concrete‐face rockfill dams and the impact of compacted rockfill on the concrete face rockfill dam. Emphasis in this paper is directed towards the concrete face type of rockfill dam, since the earth core type is already well‐covered in the literature. Recent progress in the design and construction of the concreteface rockfill dam is outlined and documented. Design trends and performance data are presented.

The Jebba Main Dam is founded on alluvial sands up to 230 ft (70 m) in depth. Soil investigation established the presence of locally loose materials at various depths. The test methods of the original investigation are described, and the soil parameters measured are presented. A short description of design considerations is followed by a detailed description of field tests with different vibrocompaction equipment, deep blasting, and penetrometer equipment. Production work included densification of approximately $308\text{,}700{\mathrm{yd}}^3$ $\left(236\text{,}000m^3\right)$ by deep blasting and $3\text{,}492\text{,}200{\mathrm{yd}}^3$ $\left(2\text{,}670\text{,}000m^3\right)$ of foundation materials by vibrocompaction method, and represents one of the largest groundimprovement programs ever undertaken.

Data are presented from cyclic triaxial tests on remoulded clays with load or displacement control. The ability of simple load control tests to predict strains developed in complex (storm profile) tests is found inadequate. It is suggested that only the minimum cyclic stress ratio associated with the fully weakened state has any direct design relevance. The minimum cyclic stress ratio varies with frequency. If data from load controlled tests are re‐analyzed to account for rate effects on shear strength then a constant value independent of frequency is observed. However, measurement is approximate and requires several extended tests. It is found that the fully weakened state for the soil tested can be achieved in a single displacement controlled test provided that 10,000 cycles at a mean double amplitude strain of at least 5% are applied. Irrespective of data re‐analysis, the minimum cyclic stress ratio measured in a single displacement controlled test is constant for frequencies less than 1/5 Hz. Within this limit the values of this parameter obtained from the two test modes agree to within 10%.

A method is presented for calculating the interlock tensions in the sheetpile walls of a circular cellular cofferdam. A horizontal strip of unit width of wall is considered and the governing equations are derived from equilibrium and compatibility requirements for the strip. The pressure of the cell fill against the sheetpile walls is assumed known. Numerical examples are presented in which interlock tensions in the arc cell, main cell, and common‐wall are calculated for various pressures. Bulging of the cell walls and rotation of the legs of the connecting Y are also found. The calculations provide theoretical justification for use of an equation for estimating the force in the common‐wall and lead to a generalization of that equation. The method may be applied to other sheetpile wall configurations besides those of a circular cofferdam.

Strontium distribution coefficients were determined on samples of glacial till from two sites in Southern Ontario to investigate the effect of natural strontium concentrations on measured distribution coefficient (Kd) values. The distribution coefficients were determined by the ‘batch’ method using synthetic ground water solutions prepared on the basis of 1:1 soluble soil extract analysis. A regression analysis of Sr Kd versus soluble strontium content of the soil materials indicated a strong relationship between decreasing Sr Kd and increasing natural strontium concentrations with a correlation coefficient of $-0.8511\text{.}$ Batch tests performed using stable strontium showed that the horizontal section of the distribution curve observed using the conventional radiometric method of analysis is not representative of varying Sr concentrations but is a result of Kd values determined at one Sr concentration, due to the natural Sr content of the soil material. Removal of the natural Sr caused an increase in the measured Kd value. This increase in Kd, coupled with the previous observations, provides evidence that the Sr Kd values for the soils studied are significantly affected by the natural Sr content of the soils. The effect on Kd values by background isotopes has important implications with respect to both the measurement of Kd values and with respect to their field application in as much as Kd values could be altered by any changes in the natural concentration of stable isotopes of the radionuclides of interest.

In this paper, a novel analysis is proposed to predict the pressure‐settlement characteristics of footings using the hyperbolic stress‐strain curves of soils as the constitutive law. The analysis is competent to incorporate the effect of shape, base roughness, and flexibility of the footings. Analyses are developed both for strip and square footings. Results are examined in terms of ultimate bearing capacity, settlement at failure, and nondimensional correlations of settlement. Analytical data are compared with available experimental results and show excellent agreement.

Triaxial tests with confining pressures of up to 2000 psi (14 MPa) to simulate the overburden pressure in oil shale formations are performed on duplicate sets of cores taken from Silver Point Quad in DeKalb County, Tennessee. Oil yields in the samples ranged from 8.4 gal/ton to 15.6 gal/ton (or 35 l/t to 65 l/t). A Mohr-Coulomb failure model was developed making use of p-q plots and statistical analysis. A significant finding of this study is that the failure of Tennessee oil shale under confining pressures is independent of the richness of the oil shale. Cohesion and angle of internal friction of oil shale are obtained with high accuracy. Possible mechanisms are discussed.

Railroad embankments are designed for almost no residual soil displacement by providing adequate depth of ballast. Formulations for evaluating dynamic shear modulus and damping ratio from commonly known soil indices such as C', 0', OCR, Gm, etc., under small 1=1 strain assumption can be used conveniently in the dynamic analysis of railway embankments, thus obviating the need to conduct elaborate field or laboratory experiments. These formulations are presented.

Laboratory bearing capacity model tests were performed on both reinforced and unreinforced sand loaded by a strip footing. The effects of soil density and reinforcing strip length were investigated. The tests show that a significant increase in bearing capacity can be achieved at relative densities between 51 and 90% by the use of metal reinforcing strips. Bearing capacity of reinforced sand is a strong function of the length of the reinforcing strips only until the strip length reaches approximately seven times the footing width; additional length does not significantly increase bearing capacity. For those tests on unreinforced sand where a distinct peak in the load-bearing pressure curve occurs (general shear failure), the failure of the corresponding reinforced sand occurs at a larger settlement. A comparison of test results with an analytical method of predicting bearing capacity of reinforced sand shows the importance of the soil-reinforcing strip friction coefficient.

The effect and the possible performance of soil-metallic powders reinforcement systems are evaluated. A series of undrained triaxial compression tests were carried out on cylindrical samples of silty clay reinforced with metallic powders (aluminum and cast iron) at various percentages by weight of the soil. The inclusion of metallic powder in earth improved both the strength and deformation behavior of soil substantially. The addition of small amounts of metallic powder significantly increased the maximum principal stress difference of soil sample. The metallic powder imparted additional cohesion to the soil to a significant extent.

Available laboratory data on clays tested for both lateral stress coefficient behavior and undrained shear strength are reviewed. Since the coefficient of earth pressure at-rest and normalized undrained shear strength during unloading are both functions of the overconsolidation ratio, direct relationships are formulated between the normalized at rest coefficient and normalized strength.

A method proposed for determining the safety factor against wall collapse of a circular, unbraced excavation in a homogeneous soft clay is extended to account for a varying strength profile. A trial analysis indicates that the calculated safety factors correspond to variable local (i.e., Detroit) field experience.