A study of the post‐construction crest settlements and deflections of 68 rockfill dams has been made in order to assess the usefulness and accuracy of the prediction of such deformations using empirical equations. Graphs of deformation per unit height against time are plotted for membrane‐faced (dumped and compacted rockfill), sloping, and central core dams. Comparisons of predicted and observed movements show that use of empirical equations can lead to large errors. An alternative approach is proposed, using only the deformation curves of existing dams with similar characteristics to the dam under consideration. Details are given in tabular form for each of the dams in the survey, as an aid to this approach.

An offshore fleet of about 435 mobile jack‐up rigs is currently drilling oil and gas wells around the world. About 2.6% of these jack‐up rigs annually experience an accident which is far greater than any other type of offshore drilling unit. Over one‐third of these accidents are associated with foundation problems. Certain geological conditions pose particular hazards to the foundation performance of mobile jack‐up rigs. To reduce the risk of foundation failure, these hazards can and should be identified by investigating subsurface conditions. Considerable interest is being given to assessing the accuracy of the analytical methods now available to predict the foundation performance of jack‐up drilling rigs. Some commonly used analytical methods are reviewed and actual case histories are presented.

TO avoid the complication in the calculation of progressive failure using the stress‐strain approach, and the inaccuracy of using the pseudo‐static analysis in seismic slope stability analysis, it is desirable to develop an effective method with which the critical state of the slope and the effects of earthquake on the slope stability can be determined directly. The present work is an attempt, within the framework of conventional pseudo‐static analysis, to develop a model for the evaluation of the critical state and the subsequent displacement response of slopes to earthquakes. The upper‐bound pseudo‐static limit analysis is applied for the determination of critical state of slopes, in this case, the yield acceleration and corresponding failure mechanism. Based on the calculated yield acceleration and the critical failure surface, Newmark's analytical procedure is then used to assess the soil displacements of slopes, which are subjected to a given earthquake load.

The mudstone underlying the Melbourne area forms the principal bearing stratum of the region. Because of its wide range of weathering characteristics, the mudstone is transitional between soils and more competent hard rocks. Little quantitative engineering data is available for these weak rocks and therefore a comprehensive series of laboratory tests including uniaxial compression tests, Brazilian tests, direct shear tests and triaxial compression tests, on several hundred individual intact specimens of the mudstone were performed. The variation of strength across a wide range of weathering characteristics is investigated. The suitability of several failure criteria is examined. A new nonlinear criterion is proposed and is shown to adequately predict the strength of the mudstone for the range of testing conditions considered.

Steady‐state flow through an earth dam with an impervious core and a cutoff extended various depths into an alluvial foundation was examined for dependance on the permeability ratio of the foundation and depth of the cutoff. The flow which can be calculated by hand by assuming water moving through the foundation alone, was compared to a more complete model including flow through the dam. The simplified assumptions for flow only through the foundation may be used for cases of horizontal permeability 10 to 100 times vertical permeability and cutoff depth ranging from 35%–100% of the foundation depth to give results within 10% of those of the more complete model.

A study is conducted to examine the parameters governing the coefficient of soil reaction $k_n$ normal to the surface of conduits as well as the coefficient $k_s$ tangential to the wall surface, and simple formulas are developed for their evaluation. Both circular and elliptical conduits are taken into consideration, as well as two types of soil, namely very dense and medium‐dense fillings. The coefficients of soil reaction are obtained by relating the results of internal force components and conduit deformations calculated with rigorous finite element analysis to equivalent results obtained from the system modeling of the problem. The results show that the coefficients of soil reaction vary considerably around the conduit. They are dependent on the span of conduit, the depth of soil and the direction of action.

Many earth dams exhibit lateral deformation during construction; the extent is dependent upon the stress‐strain characteristics of the embankment material. Earth dams constructed exclusively of impervious fill have the capacity to exhibit extensive plastic deformation, or bulging, of the embankment mass. The major cause of lateral bulging is molding water contents in excess of optimum. The analyses of two recently constructed earth dams, and the review of an earlier, similar experience, have led to the development of a simplified procedure for predicting the extent of lateral bulging.

The uncertainties encountered in the stability analysis for the foundation of the Ekofisk Tank are formulated in probabilistic terms and used to evaluate the reliability of the foundation design. The major sources of uncertainty are: shear strength of the soil, wave loads, porepressure generation under repeated loads, and methods of analysis. The results show that the conservative assumptions and low safety factor, based on the information available at the time of design, lead to a reliability that is close to those reported for other offshore foundations in the North Sea. About the same reliability is obtained by an estimate made on the basis of current knowledge. This study demonstrates the use of reliability analysis in designs involving complex loadings and inadequate knowledge on soil behavior. The procedures are comparatively simple and may be applied to new designs to help the engineer in making decisions about safety factors.

High ground‐water levels are a principal cause of slope instability and of significance in other geotechnical engineering problems. A methodology has been developed, and is described in this paper, for predicting the fluctuation of ground‐water levels as a function of precipitation. The approximate method uses measured characteristics of the site or region and a short period of calibration from a well record. The linkage of precipitation to ground‐water fluctuation can be used in either deterministic or probabilistic methods. The new methodology has been tested by application in several different geological and climatological areas. Based on these field studies, the sensitivity of the methodology to calibration period, aquifer response time, evapotranspiration and other characteristics has been evaluated. The overall conclusion of the work has been a demonstration that the fluctuation of ground‐water levels, including extreme values, can be predicted with sufficient accuracy for many design and analysis problems.

In order to demonstrate the effect from a strip load on the design of sheet pile walls, the earth pressure on a rigid vertical wall rotating about a point near the top of the wall is calculated for cohesionless soil using Brinch Hansen's earth pressure theory. A complete analytical solution corresponding to the calculation of the earth pressure by means of a circular failure arc is given together with charts demonstrating the results for the (plane) internal angle of friction $\varphi =\mathrm{30deg};\text{.}$ It is shown that the surcharge/unit weight ratio and the position of the strip load has significant influence on the design loads and that simple rules‐of‐the‐thumb should be carefully examined in order to ensure safe design procedures.