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Behavior of braced excavation in sand under a seismic condition: experimental and numerical studies 总被引：1，自引：1，他引：0
The behavior of braced excavation in dry sand under a seismic condition is investigated in this paper. A series of shake table tests on a reduced scale model of a retaining wall with one level of bracing were conducted to study the effect of different design parameters such as excavation depth, acceleration amplitude and wall stiffness. Numerical analyses using FLAC 2D were also performed considering one level of bracing. The strut forces, lateral displacements and bending moments in the wall at the end of earthquake motion were compared with experimental results. The study showed that in a post-seismic condition, when other factors were constant, lateral displacement, bending moment, strut forces and maximum ground surface displacement increased with excavation depth and the amplitude of base acceleration. The study also showed that as wall stiffness decreased, the lateral displacement of the wall and ground surface displacement increased, but the bending moment of the wall and strut forces decreased. The net earth pressure behind the walls was influenced by excavation depth and the peak acceleration amplitude, but did not change significantly with wall stiffness. Strut force was the least affected parameter when compared with others under a seismic condition. 相似文献
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It is well known that the generation of excess pore water pressure and/or liquefaction in foundation soils during an earthquake often cause structural failures.This paper describes the behavior of a small-scale braced wall embedded in saturated liquefiable sand under dynamic condition.Shake table tests are performed in the laboratory on embedded retaining walls with single bracing.The tests are conducted for different excavation depths and base motions.The influences of the peak magnitude of the ground motions and the excavation depth on the axial forces in the bracing,the lateral displacement and the bending moments in the braced walls are studied.The shake table tests are simulated numerically using FLAC 2D and the results are compared with the corresponding experimental results.The pore water pressures developed in the soil are found to influence the behavior of the braced wall structures during a dynamic event.It is found that the excess pore water pressure development in the soil below the excavation is higher compared to the soil beside the walls.Thus,the soil below the excavation level is more susceptible to the liquefaction compared to the soil beside the walls. 相似文献
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Raj Banerjee Sanku Konai Aniruddha Sengupta Kousik Deb 《Geotechnical and Geological Engineering》2017,35(4):1327-1340
As a part of the seismic safety evaluation of several bridges and other hydraulic structures located on Kasai River bed in India, the liquefaction potential of Kasai River sand is studied in 1-g shake table in laboratory and numerically using a commercial software FLAC 2D. The surface settlement, lateral spreading, predominant frequency, amplification of the ground motion and pore water pressure development in Kasai River sand in dry and liquefied states have been studied when subjected to sinusoidal motions of amplitude 0.35 g at a frequency of 2 Hz. The nonlinear curves used to represent shear strain dependency of stiffness and damping ratio of Kasai River sand are obtained from cyclic triaxial tests. Reasonably good agreement between the experimental and the numerical results is observed. It is found that the settlement and lateral spreading for the liquefied sand is 2.60 and 2.50 times than those of the sand in the dry state. The volumetric strain of the liquefied sand is found to be around 4%, which is significantly higher than 1.53% observed in the dry sand. It is observed that the amplification of the peak ground acceleration for the saturated sand is 1.08 and 1.32 times higher than that for the dry sand from theoretical and experimental results, respectively. The shear strain developed in the liquefied sand is 1.17 times more than that for dry sand. The fundamental and higher modal frequencies of dry sand are found to be 1.13, 1.117 and 1.119 times more than those for the saturated sand, respectively. 相似文献
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