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Risk in geotechnical works: conceptual and practical suggestions
190A
923397 Risk in geotechnical works: conceptual and practical suggestions de Mello, V F B Proc 8th Pcmamericu Cos~ference on Soil Mec&mics aml Foundau'on Engiacering, Cm'tage~, 15-21 Amgast 1987 V4, P319-347. Publ SCG: Colombia, 1991
the hillside were still unstable, and remedial measures were necessary to protect the wells. Surface drainage to remove runoff quickly, plus crated masonry and piled concrete retaining walls are proposed. In addition, grouting of existing surface cracks and encouragement of slope vegetation are suggested.
Engineering design requires balance of adequate safety factors with overall costs. Initial approaches were based on static factors of safety. Probabilistic approaches were later developed as a refined method of risk assessment. A suggested method involves evaluating the changes in safety factors resulting from changes in nominal initial conditions or properties and calculating changes in risk probability. This can be applied in back analysis or re-analysis of existing cases. A number of failure examples is examined in this manner.
923401
923398 Slope stlbility using optimization technique Joshi, D K; Govil, A K Proc l~lian Geoteclmical Conference, 1989, Geotecimiqacs of Problematic Soils and Rocks, gisaklmpatMm, 14-16 December 1989 VI, P469-471. Pubi New Delhi: Sarita Prakashan, 1989 Various methods available for determining the factor of safety of a soil slope and their limitations are briefly listed. An alternative approach is presented in which a closed form nondimensional slope stability is formulated by introducing a Heaviside unit function and co-ordinates of the centre of the slip surface. Optimal solutions of the derived equations can be obtained using a first order optimisation technique. The function eliminates the necessity to divide the soil mass into slices. Failure surfaces are close to those of the Bishop analysis. 923399 Rook creep induced slope failures in Part of Chonab Valley -a case study for Nera slide along National Highway 1A, Jammu and Kashmir Pande, P; Sharda, Y P; Sinha, A K Proc Indian Geotechnical Conference, 1989, Geoteclmiques of Problematic Soils and Rocks, Visakhapatnam, 14-16 December 1989 V1, P477-481. Publ New Delhi: Sarita Prakashan, 1989 Repeated landslides have occurred along the Ramban section of IA where Precambrian slates, quartzites, and phyllites lie between two major thrusts. Anomalous surface reversal of dips is evident at places in the metasedimentaries. These could be the results of rock creep, slow flow of the near-surface rock downslope under gravitational loading, for which the conditions of high relief and unconfined topography are favourable. A typical example is presented. Short and long term remedial and preventative measures are described. 923400
Investigation of landslide and suggestion for remedial measures at CN4 (ONGC) site, Changpang, Borholla, Assam - a case study Kalita, U C; Bayan, G K; Borthakur, B C; Baruah, P Proc Indian Geotecimieal Confereace, 1989, Geoteelmiqacs of Problematic Soils and Rocks, Vls~kal~tMm, 14-16 December 1989 V1, P513-517. Publ New Delhi: Sarita Prakashan, 1989 Slope failure during heavy rain and triggered by an earthquake shock threatened producing oil wells. Site investigation showed loose clayey soil to considerable depth. Stability analysis by Bishop's method suggested that the upper regions of
Evaluation of the stability of sanitary landfills Singh, S; Murphy, B J Prac Symposium on Geoteclmics of Waste Fills - Theory and Practice, Pittsborg, 10-13 Sept 1989 1'240-258. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) As availability of landfill sites is falling, one option is to build fills to greater heights in order to increase capacity. New sites are being prepared for fills of unprecedented heights, which has raised concern about their stability. Data on shear strength properties of refuse and settlement of fills are critically evaluated, and the adequacy of the Mohr-Coulomb theory to account for large, non-catastrophic deformations observed is examined. A new approach is presented for stability analysis, based on bearing capacity and settlement criteria. Dynamic strength characteristics of refuse fills and stability under seismic loading are discussed.
9234O2 Slope stability investigations at a landfill in southern California Siegel, R A; Robertson, R J; Anderson, D G Proc Symposium on Geotedmics of Waste Fills - Theory and Practice, Pittsborg, 10-13 Sept 1989 P259-284. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) The Operating Industries Inc landfill at Monterey Park, California, contains municipal and industrial refuse covered with soil of varying thickness. Slopes are up to 70m high, with narrow benches at several levels and average steepness 1:2 to 1:3. Investigations included CPTs, monitoring of inclinometers, piezometers and surface monuments, and laboratory direct shear tests on refuse. No slope failures have occurred, but surface movement and cracking are evident. Slope stability was analysed using the simplified Janbu method. Factors of safety are presented and their adequacy discussed. Dynamic stability during several earthquakes was also analysed.
9234O3 Stability consideration of vertical landfill expansions Tieman, G E; Druback, G W; Davis, K A; Weidner, C H Proc Symposium on Geoteck:dcs of Waste Fills - Theory and Practice, Ptttsborg, 10-13 Sept 1989 P285-302. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) Vertical expansions (piggybacking) of ash residue and municipal waste landfills are planned. Acceptable levels of safety against damage to liner systems by further settlement and side slope instability are essential. Design of such landfills has been studied with attention to failure of the piggyback liner system and deep seated circular failure through the existing fill and subgrade. Side slope failure along the soii-geosynthetic interface between new and existing fills is also considered. Leachate collection systems and geogrid reinforcement of subgrades are discussed.
© 1992 Pergamon Press Ltd. Reproduction not permitted
923397 Risk in geotechnical works: conceptual and practical suggestions de Mello, V F B Proc 8th Pcmamericu Cos~ference on Soil Mec&mics aml Foundau'on Engiacering, Cm'tage~, 15-21 Amgast 1987 V4, P319-347. Publ SCG: Colombia, 1991
the hillside were still unstable, and remedial measures were necessary to protect the wells. Surface drainage to remove runoff quickly, plus crated masonry and piled concrete retaining walls are proposed. In addition, grouting of existing surface cracks and encouragement of slope vegetation are suggested.
Engineering design requires balance of adequate safety factors with overall costs. Initial approaches were based on static factors of safety. Probabilistic approaches were later developed as a refined method of risk assessment. A suggested method involves evaluating the changes in safety factors resulting from changes in nominal initial conditions or properties and calculating changes in risk probability. This can be applied in back analysis or re-analysis of existing cases. A number of failure examples is examined in this manner.
923401
923398 Slope stlbility using optimization technique Joshi, D K; Govil, A K Proc l~lian Geoteclmical Conference, 1989, Geotecimiqacs of Problematic Soils and Rocks, gisaklmpatMm, 14-16 December 1989 VI, P469-471. Pubi New Delhi: Sarita Prakashan, 1989 Various methods available for determining the factor of safety of a soil slope and their limitations are briefly listed. An alternative approach is presented in which a closed form nondimensional slope stability is formulated by introducing a Heaviside unit function and co-ordinates of the centre of the slip surface. Optimal solutions of the derived equations can be obtained using a first order optimisation technique. The function eliminates the necessity to divide the soil mass into slices. Failure surfaces are close to those of the Bishop analysis. 923399 Rook creep induced slope failures in Part of Chonab Valley -a case study for Nera slide along National Highway 1A, Jammu and Kashmir Pande, P; Sharda, Y P; Sinha, A K Proc Indian Geotechnical Conference, 1989, Geoteclmiques of Problematic Soils and Rocks, Visakhapatnam, 14-16 December 1989 V1, P477-481. Publ New Delhi: Sarita Prakashan, 1989 Repeated landslides have occurred along the Ramban section of IA where Precambrian slates, quartzites, and phyllites lie between two major thrusts. Anomalous surface reversal of dips is evident at places in the metasedimentaries. These could be the results of rock creep, slow flow of the near-surface rock downslope under gravitational loading, for which the conditions of high relief and unconfined topography are favourable. A typical example is presented. Short and long term remedial and preventative measures are described. 923400
Investigation of landslide and suggestion for remedial measures at CN4 (ONGC) site, Changpang, Borholla, Assam - a case study Kalita, U C; Bayan, G K; Borthakur, B C; Baruah, P Proc Indian Geotecimieal Confereace, 1989, Geoteelmiqacs of Problematic Soils and Rocks, Vls~kal~tMm, 14-16 December 1989 V1, P513-517. Publ New Delhi: Sarita Prakashan, 1989 Slope failure during heavy rain and triggered by an earthquake shock threatened producing oil wells. Site investigation showed loose clayey soil to considerable depth. Stability analysis by Bishop's method suggested that the upper regions of
Evaluation of the stability of sanitary landfills Singh, S; Murphy, B J Prac Symposium on Geoteclmics of Waste Fills - Theory and Practice, Pittsborg, 10-13 Sept 1989 1'240-258. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) As availability of landfill sites is falling, one option is to build fills to greater heights in order to increase capacity. New sites are being prepared for fills of unprecedented heights, which has raised concern about their stability. Data on shear strength properties of refuse and settlement of fills are critically evaluated, and the adequacy of the Mohr-Coulomb theory to account for large, non-catastrophic deformations observed is examined. A new approach is presented for stability analysis, based on bearing capacity and settlement criteria. Dynamic strength characteristics of refuse fills and stability under seismic loading are discussed.
9234O2 Slope stability investigations at a landfill in southern California Siegel, R A; Robertson, R J; Anderson, D G Proc Symposium on Geotedmics of Waste Fills - Theory and Practice, Pittsborg, 10-13 Sept 1989 P259-284. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) The Operating Industries Inc landfill at Monterey Park, California, contains municipal and industrial refuse covered with soil of varying thickness. Slopes are up to 70m high, with narrow benches at several levels and average steepness 1:2 to 1:3. Investigations included CPTs, monitoring of inclinometers, piezometers and surface monuments, and laboratory direct shear tests on refuse. No slope failures have occurred, but surface movement and cracking are evident. Slope stability was analysed using the simplified Janbu method. Factors of safety are presented and their adequacy discussed. Dynamic stability during several earthquakes was also analysed.
9234O3 Stability consideration of vertical landfill expansions Tieman, G E; Druback, G W; Davis, K A; Weidner, C H Proc Symposium on Geoteck:dcs of Waste Fills - Theory and Practice, Ptttsborg, 10-13 Sept 1989 P285-302. Publ Philadelphia: ASTM, 1990 (ASTM Special Technical Publication 1070) Vertical expansions (piggybacking) of ash residue and municipal waste landfills are planned. Acceptable levels of safety against damage to liner systems by further settlement and side slope instability are essential. Design of such landfills has been studied with attention to failure of the piggyback liner system and deep seated circular failure through the existing fill and subgrade. Side slope failure along the soii-geosynthetic interface between new and existing fills is also considered. Leachate collection systems and geogrid reinforcement of subgrades are discussed.
© 1992 Pergamon Press Ltd. Reproduction not permitted