地震时地下连续墙围束效应与围束土壤超孔隙水压力之探讨

以三维有限元程序仿真研究受地下连续墙围束土壤其受震时之反应。以1995年阪神地震波为输入条件,土体为中紧密度砂土及疏松砂土时发现:随着地震方向地下连续墙位置之靠近,围束体内部的土体最大水平向位移将跟着减少,其中又以在中紧密度砂的效果明显于松砂之效果;在松砂中之超孔隙水压生成速度明显比中紧密砂快;中紧密砂中之超孔隙水压于受激发过程会因土体剪胀之故,局部期间有下降现象;中紧密砂之液化因地下连续墙围束效应明显降低。

Numerical study on seismic interaction between wall-type underground structures and excess pore water pressure of confined soils

A 3D FEM program was used to analyze the seismic behaviors of wall confined soils of underground. Taking 1995 Kobe Earthquake waves as input and assuming that the ground was composed of medium dense sand and loose sand, it was shown that horizontal displacement of the enclosed medium dense soils decreased as a result of wall confinement. The excess pore water pressure of the confined soils was strongly excited due to soil-structure interaction. However, the development of excess pore water pressure of confined soils reduced with the decrease of distance between two sides of the wall, especially in the case of medium dense sand. The sudden drop of development of excess pore water pressure of medium dense sand took place due to soil dilantancy and the confinement effect greatly reduced the occurrence of the soil liquefaction in enclosed area.