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Dynamic response of axisymmetric embedded foundations
183A
Groundwater problems 903419 Deep overburden shaft collar - Musselwhite project case history Winship, M D; Martin, G S CIM Bull V82. ,%'930, Oct 1989, P53-58 Shaft sinking through 16m of water bearing sand and till overburden is described. Ten soldier piles were first driven to sockets in bedrock, then interlocking sheet piles were driven as deep as possible (7.5-10m) on the outside of the soldier piles. Six dewatering wells were installed. Excavation problems first arose when the bottom of the sheet piles was reached and water flow increased. Extra wells could not cope and wooden lagging was installed as depth increased. Further problems occurred when bedrock was reached, caused by water flow along the rock/sand interface. Drainage pipes were installed and a shaft collar concreted before rock excavation began.
Influence of dynamic loads 903420 Foam rubber modeling of topographic and dam interaction effects at Pacoima Dam Anooshehpoor, A; Brune, J N Bull Seismol Soc Am V79. N5. Oct 1989, PI347-1360 Large horizontal ground accelerations were recorded at the Pacoima Dam station during the 1971 San Fernando earthquake. To examine topographic effects on amplification or attenuation of ground motion, a 3D foam rubber model of the valley was subjected to simulated earthquake excitation. Results show that the topographic effect is dependent on the direction of approach of the seismic energy, whether the canyon is on the ray path or not. Dynamic interaction between dam and ridge was also studied. 90342 I Dynamic response of axisymmetric embedded foundations Emperador, J M; Dominguez, J Earthq Engng Struct Dynam VI8, N8, Not' 1989, P1105-1117 Dynamic stiffness functions of rigid cylindrical foundations embedded in a uniform or layered viscoelastic half space, and of hemispherical foundations in a uniform half space are obtained using the boundary element method. The direct integral formulation is used together with the complete space point load fundamental solution. Numerical results from this easily implemented method are close to other published results. Effects of Poisson's ratio for the uniform half space and of bedrock compliance for the layered case are investigated. 903422 Centrifugal modelling of dynamic soil-structure interaction Weissman. K; Prevost, J H Earthq Engng Struct Dynam VI8, NS, Nor 1989. P1145-1161 A centrifuge model has been developed which can realistically represent soil-structure systems under earthquake excitations. It is validated by free field soil tests, dynamic soil structure interaction tests, and numerical analysis of experimental results. The apparatus is lined with a layer of absorptive material to permit simulation of infinite horizontal soil strata. Dependence of radiation damping on natural frequencies of structure and soil strata has been investigated. Results are consistent with established theory. Stiffness and damping parameters obtained for a two degree of freedom model agree well with classical formulae, suggesting more complicated systems can be studied with this apparatus.
903423 Boundary element approach to the dynamic stiffness functions of circular foundations Alarcon, E; Cano. J J; Dominguez, J Int J Num Anal Meth Geomech VI3. N6, Nor-Dec 1989, P645-664 A boundary element approach to the dynamic response of axisymmetric foundations, based on the complete space point load fundamental solution, is presented. Dynamic stiffness (impedance) functions are evaluated for three different site conditions: uniform half space, soil on a half space,and layered soil on a compliant half space. Comparison of results with other published solutions indicates a high degree of accuracy. 903424 Study on lateral dashpots for soil-structure interaction and its application to a simplified technique Fukuwa, N; Nakai. S Soils Found V29. N3. Sept 1989. P25-40 Dynamic characteristics of embedded rigid foundations are studied using the boundary element method. Lateral dashpots are introduced to the soil in plane strain to represent the wave propagation for a soil slice in the third direction. Efficiency of the dashpots is evaluated by comparing results from 2D, approximate 3D and exact 3D analyses. Based on these results, lateral dashpots are introduced to one dimensional soil columns which represent a half space around an embedded foundation. Impedance functions are then easily obtained in an explicit form and foundation input motions evaluated using the substructure technique. Validity of this simplified procedure is demonstrated. 903425 Analytical solution for Newmark's sliding block. Technical note Conte, E; Dente, G Soils Found V~9. N3, Sept 1989, PI52-156 Newmark (1965) suggested that the sliding soil mass of earth dams or slopes can, under dynamic conditions, be modelled as a sliding block on an inclined slope with rigid-plastic sliding resistance. A solution for monopulse or cyclic loads is presented. Interaction between pulse loads can be aualysed. For seismic loading where critical acceleration is exceeded by only a few of the pulses, a solution may be easily obtained. 903426 Method to evaluate the dynamic stability of hydraulic fill structures Bhatia, S K; Schwab. J P; lshibashi, I Proc Conference on Hydraulic Fill Structures, Fort Collins, 15-18 April 1988 P529-548. Publ New York: ASCE. 1988 (Geotechnical Special Publication No 21) Development of an analytical method to predict cyclic response of soil under combined static and dynamic loading is discussed. A review of existing knowledge of sand cyclic behaviour is first presented. Ottawa sands were tested under strain controlled conditions using torsional shear apparatus, with pore pressure buildup, shear stresses and shear strains monitored. Results were evaluated to devise new pore pressure and stress strain models. These models are then formulated into effective stress analysis. Analysis of 2 dams illustrates use of the method.
© 1990 Pergamon Press plc. Reproduction not permitted
Groundwater problems 903419 Deep overburden shaft collar - Musselwhite project case history Winship, M D; Martin, G S CIM Bull V82. ,%'930, Oct 1989, P53-58 Shaft sinking through 16m of water bearing sand and till overburden is described. Ten soldier piles were first driven to sockets in bedrock, then interlocking sheet piles were driven as deep as possible (7.5-10m) on the outside of the soldier piles. Six dewatering wells were installed. Excavation problems first arose when the bottom of the sheet piles was reached and water flow increased. Extra wells could not cope and wooden lagging was installed as depth increased. Further problems occurred when bedrock was reached, caused by water flow along the rock/sand interface. Drainage pipes were installed and a shaft collar concreted before rock excavation began.
Influence of dynamic loads 903420 Foam rubber modeling of topographic and dam interaction effects at Pacoima Dam Anooshehpoor, A; Brune, J N Bull Seismol Soc Am V79. N5. Oct 1989, PI347-1360 Large horizontal ground accelerations were recorded at the Pacoima Dam station during the 1971 San Fernando earthquake. To examine topographic effects on amplification or attenuation of ground motion, a 3D foam rubber model of the valley was subjected to simulated earthquake excitation. Results show that the topographic effect is dependent on the direction of approach of the seismic energy, whether the canyon is on the ray path or not. Dynamic interaction between dam and ridge was also studied. 90342 I Dynamic response of axisymmetric embedded foundations Emperador, J M; Dominguez, J Earthq Engng Struct Dynam VI8, N8, Not' 1989, P1105-1117 Dynamic stiffness functions of rigid cylindrical foundations embedded in a uniform or layered viscoelastic half space, and of hemispherical foundations in a uniform half space are obtained using the boundary element method. The direct integral formulation is used together with the complete space point load fundamental solution. Numerical results from this easily implemented method are close to other published results. Effects of Poisson's ratio for the uniform half space and of bedrock compliance for the layered case are investigated. 903422 Centrifugal modelling of dynamic soil-structure interaction Weissman. K; Prevost, J H Earthq Engng Struct Dynam VI8, NS, Nor 1989. P1145-1161 A centrifuge model has been developed which can realistically represent soil-structure systems under earthquake excitations. It is validated by free field soil tests, dynamic soil structure interaction tests, and numerical analysis of experimental results. The apparatus is lined with a layer of absorptive material to permit simulation of infinite horizontal soil strata. Dependence of radiation damping on natural frequencies of structure and soil strata has been investigated. Results are consistent with established theory. Stiffness and damping parameters obtained for a two degree of freedom model agree well with classical formulae, suggesting more complicated systems can be studied with this apparatus.
903423 Boundary element approach to the dynamic stiffness functions of circular foundations Alarcon, E; Cano. J J; Dominguez, J Int J Num Anal Meth Geomech VI3. N6, Nor-Dec 1989, P645-664 A boundary element approach to the dynamic response of axisymmetric foundations, based on the complete space point load fundamental solution, is presented. Dynamic stiffness (impedance) functions are evaluated for three different site conditions: uniform half space, soil on a half space,and layered soil on a compliant half space. Comparison of results with other published solutions indicates a high degree of accuracy. 903424 Study on lateral dashpots for soil-structure interaction and its application to a simplified technique Fukuwa, N; Nakai. S Soils Found V29. N3. Sept 1989. P25-40 Dynamic characteristics of embedded rigid foundations are studied using the boundary element method. Lateral dashpots are introduced to the soil in plane strain to represent the wave propagation for a soil slice in the third direction. Efficiency of the dashpots is evaluated by comparing results from 2D, approximate 3D and exact 3D analyses. Based on these results, lateral dashpots are introduced to one dimensional soil columns which represent a half space around an embedded foundation. Impedance functions are then easily obtained in an explicit form and foundation input motions evaluated using the substructure technique. Validity of this simplified procedure is demonstrated. 903425 Analytical solution for Newmark's sliding block. Technical note Conte, E; Dente, G Soils Found V~9. N3, Sept 1989, PI52-156 Newmark (1965) suggested that the sliding soil mass of earth dams or slopes can, under dynamic conditions, be modelled as a sliding block on an inclined slope with rigid-plastic sliding resistance. A solution for monopulse or cyclic loads is presented. Interaction between pulse loads can be aualysed. For seismic loading where critical acceleration is exceeded by only a few of the pulses, a solution may be easily obtained. 903426 Method to evaluate the dynamic stability of hydraulic fill structures Bhatia, S K; Schwab. J P; lshibashi, I Proc Conference on Hydraulic Fill Structures, Fort Collins, 15-18 April 1988 P529-548. Publ New York: ASCE. 1988 (Geotechnical Special Publication No 21) Development of an analytical method to predict cyclic response of soil under combined static and dynamic loading is discussed. A review of existing knowledge of sand cyclic behaviour is first presented. Ottawa sands were tested under strain controlled conditions using torsional shear apparatus, with pore pressure buildup, shear stresses and shear strains monitored. Results were evaluated to devise new pore pressure and stress strain models. These models are then formulated into effective stress analysis. Analysis of 2 dams illustrates use of the method.
© 1990 Pergamon Press plc. Reproduction not permitted