The effect of cutoff walls on the seismic behavior of underground structures in liquefiable soil

Underground structures such as subway tunnels, water pipe lines, manholes and etc. are indispensable parts of urban zone used for various applications. Shallow underground structures buried in liquefiable soils may experience extensive damages such as floatation or sinking and extra lateral displacement due to earthquake induced soil liquefaction. Different mitigation strategies have been developed for eliminating or alleviating uplift of underground structures such as densification or replacement of surrounding liquefiable soils, installation of gravel drainages, cutoff walls, grouting and etc. In this paper, at first, the uplift mechanism of underground structures in liquefiable sand soil is explaned; then, the mechanism of cutoff walls in aloviating uplift response and their interaction with subway are studied. The cutoff walls parameters variation effect on interaction behavior of the adjacent subway is numerically investigated. At the end, the effects of dense soil columns installation on the subway reponses are compared with cutoff walls influences

Keywords:

Underground tunnels , Uplift , Cutoff walls , Liquefaction , Earthquake