Stephen G. Wright

Bio: Stephen G. Wright is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Slope stability & Shear strength. The author has an hindex of 15, co-authored 40 publications receiving 1540 citations. Previous affiliations of Stephen G. Wright include Virginia Tech.

Soil Strength and Slope Stability

Abstract: This book describes the state-of-the-art methodology for evaluating and analyzing soil strength and the design and stabilization of slopes in soil. Focus is on the principles of limit equilibrium analysis and the appropriate use of computer programs. Methods are also presented for checking the results of complex analyses and for presenting results of slope stability analyses.

Slope reliability analysis using generalized method of slices

Abstract: Chen and Morgenstern extended Morgenstern and Price's method of slices by expressing force and moment equilibrium in two equations involving multiple integrals. In the present study a practical nested quadrature integration procedure is proposed and implemented in a spreadsheet, to obtain the factor of safety and side force inclinations that satisfy the Chen-Morgenstern equations. Since the deterministic factor-of-safety analysis does not explicitly reflect the uncertainties of the parameters that affect performance, the paper next considers the Hasofer-Lind second moment reliability index. It is shown that extending from the deterministic analysis—a demanding task in its own right, traditionally—to the hitherto equally complicated reliability index computation requires little extra effort. The spreadsheet approach is powerful and versatile, yet practical, and it affords the user an appreciation of what is being implemented.

Wave‐Induced Slides in South Pass Block 70, Mississippi Delta

Abstract: Failure of a major offshore platform caused by a seafloor slide and hurricane wave forces is described. Data on the soils and waves are combined with limit equilibrium, finite element and layered continuum analytical models to determine soil movements and forces. Estimates are made of the ultimate strength of the platform foundation. Comparison of force and resistance characterizations indicates good agreement. Ultimate strength design methods are suggested to supplement present elastic methods in design of slide‐resistant platforms.

Watershed delineation with triangle-based terrain models

Abstract: An algorithm is presented for tracing the path of steepest descent from a given starting point on a terrain model defined by a triangulated irregular network. This algorithm is then extended to solve several problems. The flow patterns for a site are generated by tracing flow paths from a large number of starting points. The approximate stream network or channel network is found by tracing the channels upstream from pits or exit points. Once the stream network is found, the source areas or contributing areas for each of the sections of the stream are delineated. The source areas are then used to delineate the watersheds of selected nodes in the channel network. The format of a possible data structure for the channel network is presented along with pseudocode examples for traversing the channel network and the source areas. Execution times on a desktop computer are presented along with suggestions for optimal use of the algorithms.

Accuracy of Equilibrium Slope Stability Analysis

Abstract: The accuracy of limit equilibrium slope stability analyses procedures is examined by comparing the results of the Simplified Bishop procedure with results obtained using the finite element procedure of analysis. The distributions of normal stresses along the shear surface were compared and found to be reasonably similar, the agreement between the two procedures being closest for relatively flat slopes with relatively low values of cohesion. The values of the factor of safety, while assumed constant in the Bishop procedure, were shown by the finite element analyses to vary considerably along the shear surface. However, the overall, or average, values of the factor of safety computed by these two procedures were found to agree within 5 percent over the range of conditions investigated. It was concluded from these results that the Simplified Bishop procedure, as well as many other limit equilibrium analysis procedures, do not involve large errors in the computed values for the overall factor of safety of earth slopes.

State of the Art: Limit Equilibrium and Finite-Element Analysis of Slopes

Abstract: In the past 25 years great strides have been made in the area of static stability and deformation analysis. The widespread availability of microcomputers has brought about considerable change in the computational aspects of slope stability analysis. Analyses can be done much more thoroughly, and, from the point of view of mechanics, more accurately than was possible without computers. Still, engineers performing slope stability analyses must have more than a computer program. They must have a thorough mastery of soil mechanics and soil strength, a solid understanding of the computer programs they use, and the ability and patience to test and judge the results of their analyses to avoid mistakes and misuse. Realistic analyses of deformations of slopes and embankments were not possible until about 25 years ago. They are possible now mainly because the finite-element method has been developed and adapted to these applications. The principal requirement for achieving reasonably accurate and useful results fro...

Submarine landslides: advances and challenges

Abstract: Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine...

Geotechnical stability analysis

Abstract: This paper describes recent advances in stability analysis that combine the limit theorems of classical plasticity with finite elements to give rigorous upper and lower bounds on the failure load. These methods, known as finite-element limit analysis, do not require assumptions to be made about the mode of failure, and use only simple strength parameters that are familiar to geotechnical engineers. The bounding properties of the solutions are invaluable in practice, and enable accurate limit loads to be obtained through the use of an exact error estimate and automatic adaptive meshing procedures. The methods are very general, and can deal with heterogeneous soil profiles, anisotropic strength characteristics, fissured soils, discontinuities, complicated boundary conditions, and complex loading in both two and three dimensions. A new development, which incorporates pore water pressures in finite-element limit analysis, is also described. Following a brief outline of the new techniques, stability solutions ...

Simplified Procedure for Estimating Earthquake-Induced Deviatoric Slope Displacements

Abstract: A simplified semiempirical predictive relationship for estimating permanent displacements due to earthquake-induced deviatoric deformations is presented. It utilizes a nonlinear fully coupled stick-slip sliding block model to capture the dynamic performance of an earth dam, natural slope, compacted earth fill, or municipal solid-waste landfill. The primary source of uncertainty in assessing the likely performance of an earth/waste system during an earthquake is the input ground motion. Hence, a comprehensive database containing 688 recorded ground motions is used to compute seismic displacements. A seismic displacement model is developed that captures the primary influence of the system’s yield coefficient ( ky ) , its initial fundamental period ( Ts ) , and the ground motion’s spectral acceleration at a degraded period equal to 1.5 Ts . The model separates the probability of “zero” displacement (i.e., ⩽1 cm ) occurring from the distribution of “nonzero” displacement, so that very low values of calculated...