Study On Dynamic Response Of Underground Structure In Liquefied And Unliquefied Foundation

Due to the frequent occurrence and significant hazard of earthquake currently, the insurance of the safety and stability of underground structures become the key point and difficulty in design study. It was shown in seismic damage data that the underground structures were subjected to different levels of destruction after earthquake, especially the underground structures built in liquefiable foundation. Therefore, it is essential to study the dynamic response of underground structures in liquefiable foundation.Based on the existing research above, the finite difference software FLAC3D was adopted to obtain the numerical calculation model for studying five-storeyed basement of a frame-core tube structure and soil surrounding. The characteristic of liquefaction was presented by calculating the excess pore water pressure and effective stress of liquefaction foundation. The dynamic response disciplines of the underground structure and soil surrounding were examined by comparing the displacement and acceleration response under liquefaction and non-liquefaction, respectively. The mechanical characteristic of underground structure in liquefied foundation was studied by comparing the force analysis under liquefaction and liquefaction. It was shown that:(1) The pore water pressure of foundation increased gradually until liquefaction. (2) The liquefaction amplified the moment and shear force of the slurry wall and side columns, indicating that the liquefaction of soil can amplify the moment and shear force of underground structure and the amplification was greater with the increasing magnitude of acceleration peak. (3) The peak of acceleration of liquefied foundation was obviously less than that of non-liquefied foundation. (4) The lateral displacement of underground structure and soil surrounding in liquefied foundation was greater than that in non-liquefied foundation, as the same with the relative displacement. It was indicated that the liquefaction had a great influence on the stability of underground structure and soil. The results obtained from this paper provide some guidance for subsequent similar projects.