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Maximum likelihood estimation of slope stability
210A
SURFACE STRUCTURES:SLOPES
dies on the German North and Baltic Sea coasts including Mecklenburg-Vorpommem. -from English summary
shear strength of their discontinuities and weak zones which are of particular significance in determining slope stability. -from Authors
Slopes
944318 Calculation of rates of displacement of viscous soil masses on a sloped surface S. R. Meschyan, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 183-188; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 2-5. This article discusses solution of the problem of determining the rates of displacement of viscous soils on a slope surface, taking into account the nonlinear relationship between deformation rates and tangential stresses, and its variability throu~.h the depth of the soil mass under the action of the soil's own we.~. t. An example is given of determining these rates at different depths of a slipping layer, as well as at different moments in time (up to 1000 days). -Journal summary
944313 Rational polynomial technique in slope-reliability analysis R . N . Chowdhury & D. W. Xu, Journal of Geotechnical Engineering - ASCE, 119(12), 1993, pp 1910-1928. This paper is concerned with the application of a numerical technique, known as the rational polynomial approximation, to the first-order second-moment method for calculating statistical moments of a performance function in reliability analysis. The approach is used for slope reliability analysis within the framework of limit equilibrium considering two recognized methods of analysis (i.e. the 1965 generalizedproc~ure of slices of Morgenstem and Price and the 1979 Sarma method). Two illustrative examples are presented in this paper: one for a homogeneous slope and the other for a slope in layered soil. The results for the reliability index are compared with two other methods, the point-estimate method and Monte-Carlo simulation method. -from Authors 944314 Slope failure analysis using local minimum factor-of-safety approach S . L . Huang & K. Yamasaki, Journal of Geotechnical Engineering- ASCE, 119(12), 1993, pp 1974-1987. An approach using the minimum factors of safety against local failures is presented. The factor of safety obtained by the proposed method is in good agreement with that determined by Bishop's and Sarma's metods. The locations of the critical slip surfaces, however, deviate slightly from Bishop s method due possibly to the assumptions made in the formulation of each method. -from Authors 944315 Convergent flow of subsurface water concerned with slope failure (in Japanese) S. Shindo, Quaternary Research (Tokyo), 32(5), 1993, pp 315-322. Discusses the mechanism of subsurface convergent flow on a slope from the standpoint of hydrogeomorphology and disaster science. Field experiments suggest that pores become enlarged by direct mechanical erosion and discharge of soluble ]~roducts to form macro pores or soil pipes. The idea of slope fatigue phenomenon' is also introduced based on the above-mentloned facts. This process is important because it enables us to estimate slope instability. -from English summary 944316 Evaluation of the effect of initial information about soilproperties on the reliability of calculating the stability of slopes and structures V. I. Rechitskii, Hydrotechnical Construction, 27(3), 1993, pp 164-171; translated from: Gidrotekhnicheskoe StroiteTstvo, 3, 1993, pp 35-40. Factors affecting the reliability of predictions concerning the stability of slopes and structures are considered, with pamcular attention to the initial data available and the calculation method selected. Factors limiting the use of probability methods included the need for certain statistical information on the main initial parameters, regarded as random variables, and the diflicu]ty of establishing standard levels of reliability where lives might be threatened by the collapse of structures. -D.W.Taylor 944317 Shear strength characteristics of discontinui. ties in weak, stratified, clay-bearing coal measures encountered in Turkish surface coal mining R. Ulusay & M. F. Yoleri, Bulletin - International Association of Engineering Geology, 48, 1993, pp 109-117. Mechanical properties of Neogene sedimentary soft rocks and their discontinuities are deteriorated by environmental ch.anges, sucn as wetting and stress release. In addition, the ~hable estim.ation of shear strength of weakness planes in m.ese rocks is a common problem. This paper aims to cnara.ctenze me engineering properties of weak, stratified, cl.ay.-be.aring coal measures encountered in surface coal mmmg m southwest Turkey with special reference to the
944319 Analysis of the stability of embankment slopes by the method of limiting equilibrium M . N . Pink, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 193-196; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 8-10. A method is suggested for calculating the slope stability of a soil mass, which differs from known methods basedon equations for the equilibrium of individual elements of the mass in its assumptions about the height of application of interelement forces to derive a solution. There is a program for automated calculation. -Journal summary 944320 Maximum likelihood estimation of slope stability N. K. Sah, P. R. Sheorey & L. N. Upadhyaya, International Journal of Rock Mechanics & Mining Sciences, 31(1), 1994, pp 47-53. Simple new empirical equations have been proposed for direct estimation of the safety factor for circular (for dry and wet slopes) and wedge (for dry slope) failure of slopes. These new equations for estimation of slope safety factor are obtained using the maximum likelihood estimation method of statistics. Twenty three dry and 23 wet case studies of circular failure and 14 dry cases of wedge failure data were collected. Good agreement is seen to exist between the safety factors predicted by the new equations and those obtained using the limit equilibrium method. -from Authors 944321 A general limit equilibrium model for threedimensional slope stability analysis L. Lain & D. G. Fredlund, Canadian Geotechnical Journal, 30(6), 1993, pp 905-919. A generalized model for three-dimensional analysis, using the method of columns, is presented. The model is an extension of the two-dimensional general limit equilibrium formulation. Intercolumn force functions of arbitrary shape can be specified to simulate various directions for the intercolumn resultant forces. A unique feature of the model involves the use of a geostatistical procedure (i.e., the thIer~ige" sing technique) in modelling the geometry of the slope, tratigraphy, the ]potential slip surface, and the porewater pressure conditions. The model was utilized to study a case history involving an open-pit mining failure. The results indicate that the model is able to provide a more re.alistic simulation of the case history than was possible using a conventional two-dimensional model. -from Authors 944322 Probabilistic evaluation on progressive failure in cut slopes H. Hayashi & W. H. Tang, Structural Safety, 14(1-2), 1994, pp 31-46. A method is developed for evaluating the static stability of a cut .slope formed by str..ain-sof~,ning soil Considering/~rogresswe zanure as me critical failure mode: The stress condition along a potential failure surface both prior to and after an excavation is d e t e ~ e d by fihite-element analysis, where the potential slip surface is modeled as joint elements. An e|asto-plastic model of shear strength versus strain is also assumed to study the redistribution of
SURFACE STRUCTURES:SLOPES
dies on the German North and Baltic Sea coasts including Mecklenburg-Vorpommem. -from English summary
shear strength of their discontinuities and weak zones which are of particular significance in determining slope stability. -from Authors
Slopes
944318 Calculation of rates of displacement of viscous soil masses on a sloped surface S. R. Meschyan, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 183-188; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 2-5. This article discusses solution of the problem of determining the rates of displacement of viscous soils on a slope surface, taking into account the nonlinear relationship between deformation rates and tangential stresses, and its variability throu~.h the depth of the soil mass under the action of the soil's own we.~. t. An example is given of determining these rates at different depths of a slipping layer, as well as at different moments in time (up to 1000 days). -Journal summary
944313 Rational polynomial technique in slope-reliability analysis R . N . Chowdhury & D. W. Xu, Journal of Geotechnical Engineering - ASCE, 119(12), 1993, pp 1910-1928. This paper is concerned with the application of a numerical technique, known as the rational polynomial approximation, to the first-order second-moment method for calculating statistical moments of a performance function in reliability analysis. The approach is used for slope reliability analysis within the framework of limit equilibrium considering two recognized methods of analysis (i.e. the 1965 generalizedproc~ure of slices of Morgenstem and Price and the 1979 Sarma method). Two illustrative examples are presented in this paper: one for a homogeneous slope and the other for a slope in layered soil. The results for the reliability index are compared with two other methods, the point-estimate method and Monte-Carlo simulation method. -from Authors 944314 Slope failure analysis using local minimum factor-of-safety approach S . L . Huang & K. Yamasaki, Journal of Geotechnical Engineering- ASCE, 119(12), 1993, pp 1974-1987. An approach using the minimum factors of safety against local failures is presented. The factor of safety obtained by the proposed method is in good agreement with that determined by Bishop's and Sarma's metods. The locations of the critical slip surfaces, however, deviate slightly from Bishop s method due possibly to the assumptions made in the formulation of each method. -from Authors 944315 Convergent flow of subsurface water concerned with slope failure (in Japanese) S. Shindo, Quaternary Research (Tokyo), 32(5), 1993, pp 315-322. Discusses the mechanism of subsurface convergent flow on a slope from the standpoint of hydrogeomorphology and disaster science. Field experiments suggest that pores become enlarged by direct mechanical erosion and discharge of soluble ]~roducts to form macro pores or soil pipes. The idea of slope fatigue phenomenon' is also introduced based on the above-mentloned facts. This process is important because it enables us to estimate slope instability. -from English summary 944316 Evaluation of the effect of initial information about soilproperties on the reliability of calculating the stability of slopes and structures V. I. Rechitskii, Hydrotechnical Construction, 27(3), 1993, pp 164-171; translated from: Gidrotekhnicheskoe StroiteTstvo, 3, 1993, pp 35-40. Factors affecting the reliability of predictions concerning the stability of slopes and structures are considered, with pamcular attention to the initial data available and the calculation method selected. Factors limiting the use of probability methods included the need for certain statistical information on the main initial parameters, regarded as random variables, and the diflicu]ty of establishing standard levels of reliability where lives might be threatened by the collapse of structures. -D.W.Taylor 944317 Shear strength characteristics of discontinui. ties in weak, stratified, clay-bearing coal measures encountered in Turkish surface coal mining R. Ulusay & M. F. Yoleri, Bulletin - International Association of Engineering Geology, 48, 1993, pp 109-117. Mechanical properties of Neogene sedimentary soft rocks and their discontinuities are deteriorated by environmental ch.anges, sucn as wetting and stress release. In addition, the ~hable estim.ation of shear strength of weakness planes in m.ese rocks is a common problem. This paper aims to cnara.ctenze me engineering properties of weak, stratified, cl.ay.-be.aring coal measures encountered in surface coal mmmg m southwest Turkey with special reference to the
944319 Analysis of the stability of embankment slopes by the method of limiting equilibrium M . N . Pink, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 193-196; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 8-10. A method is suggested for calculating the slope stability of a soil mass, which differs from known methods basedon equations for the equilibrium of individual elements of the mass in its assumptions about the height of application of interelement forces to derive a solution. There is a program for automated calculation. -Journal summary 944320 Maximum likelihood estimation of slope stability N. K. Sah, P. R. Sheorey & L. N. Upadhyaya, International Journal of Rock Mechanics & Mining Sciences, 31(1), 1994, pp 47-53. Simple new empirical equations have been proposed for direct estimation of the safety factor for circular (for dry and wet slopes) and wedge (for dry slope) failure of slopes. These new equations for estimation of slope safety factor are obtained using the maximum likelihood estimation method of statistics. Twenty three dry and 23 wet case studies of circular failure and 14 dry cases of wedge failure data were collected. Good agreement is seen to exist between the safety factors predicted by the new equations and those obtained using the limit equilibrium method. -from Authors 944321 A general limit equilibrium model for threedimensional slope stability analysis L. Lain & D. G. Fredlund, Canadian Geotechnical Journal, 30(6), 1993, pp 905-919. A generalized model for three-dimensional analysis, using the method of columns, is presented. The model is an extension of the two-dimensional general limit equilibrium formulation. Intercolumn force functions of arbitrary shape can be specified to simulate various directions for the intercolumn resultant forces. A unique feature of the model involves the use of a geostatistical procedure (i.e., the thIer~ige" sing technique) in modelling the geometry of the slope, tratigraphy, the ]potential slip surface, and the porewater pressure conditions. The model was utilized to study a case history involving an open-pit mining failure. The results indicate that the model is able to provide a more re.alistic simulation of the case history than was possible using a conventional two-dimensional model. -from Authors 944322 Probabilistic evaluation on progressive failure in cut slopes H. Hayashi & W. H. Tang, Structural Safety, 14(1-2), 1994, pp 31-46. A method is developed for evaluating the static stability of a cut .slope formed by str..ain-sof~,ning soil Considering/~rogresswe zanure as me critical failure mode: The stress condition along a potential failure surface both prior to and after an excavation is d e t e ~ e d by fihite-element analysis, where the potential slip surface is modeled as joint elements. An e|asto-plastic model of shear strength versus strain is also assumed to study the redistribution of