摘要
基于动态土工离心模型试验来研究强震动条件下液化土同桩基础的相互作用问题。设计了4个典型土工离心模型试验来研究桩土的加速度、位移等地震响应特性,再现了位于液化土地基上的实际桩基础在大地震下的破坏程度、状态和机制,并进一步对比分析试验结果,取得了较好的成果,为桩基础的抗震设计提供了可靠依据,具有重要意义。
The evaluation of liquefaction hazard and the seismic design for the pile foundation built in the liquefiable soil is potentially significant. The problem of soil-pile interaction in liquefiable soils is a nonlinear and complicated problem. Now the dynamic centrifuge test is widely used to study the seismic performance of pile foundation. Four cases of 50 g dynamic geotechnical centrifuge model test, dry sine input-wave model 1, saturation sine input-wave model 2, saturation model 3 of level 1 scenario input-wave, and saturation model 4 of level 2 scenario input-wave, are conducted to study the seismic response characteristics such as acceleration, displacement, pore water pressure of pile foundation, and mechanism of soil-pile interaction. A rectangular rigid container with internal dimensions of 150 mm×450 mm×300 nun （WxLxH） was used in the centrifuge tests. The soilprofile is comprised of one horizontal layer silica sand of about 10 m thick resting on stiff bedrock at prototype scale. The saturation soil profile is made by de-aired dry sand saturated by de-aired motolose solution of 50 times the viscosity of water that the deposit has the prototype permeability of sand. The model pile foundation consists of structure supported by a 2×2, 10 times diameter spacing pile group. Moreover, the results from centrifuge modeling are compared. It is found that displacements of saturation models are larger than those of dry models. Compared with＇dry model 1, the acceleration value of saturation model 2 descended quickly during shaking. This is may be induced by liquefaction. Sand liquefis at two depths of 2.5 m, 5.0 m in prototype scale of model 4 does not liquefy, and the excess pore water pressure dissipated slowly after shaking in model 3. The failure degree, state and mechanism of the site pile foundation in liquefiable Soil subjected to the strong motion have been discussed and a good result is achieved. These results are consistent with the one obtained from numerical simulations. This study provides a reliable foundation for the seismic design of the oversize pile foundation.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2005年第A02期5555-5560,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
安徽省自然科学基金资助项目(01045409)
关键词
土力学
液化土
桩土相互作用
土工离心模型试验
强震动
soil mechanics
liquefiable soil
soil-pile interaction
geotechnical centrifuge model test
strong motion
