高速列车振动下隧道周边砂土液化研究

Study of Sand Liquefaction under Vibration Load of High Speed Train

以广深港高速铁路狮子洋盾构隧道为背景,考虑流固耦合作用,通过FLAC3D软件对列车荷载引发的地层动力响应进行了数值模拟,分析了列车高速通过隧道时孔隙水压力和超孔压比的变化规律。计算中,采用车辆-轨道耦合模型得到列车轮轨激振力。采用循环活动性准则判别砂土液化。结果表明,高速列车荷载作用下,孔隙水压力增大,超孔压比峰值出现在地表,但其值很小,不会发生液化;两列列车交会通过隧道时,超孔压比近似对称分布,其最大值比单列列车通过情形略有增大。

Based on the program of Shiziyang shield tunnel of Guangshengang high speed railway,a fluid particle coupled model was established by FLAC3D to simulate the dynamic response of stratum induced by high speed train.The excitation loads of moving trains onto the track plate are obtained by train-track system model.The sand liquefaction is judged by the rule of cyclic mobility.The pore water pressure and excess pore water pressure ratio was analysed.Results show that the possibility of sand liquefaction is low due to low excess pore water pressure ratio,the peak value of which appeared near the landsurface.The excess pore water pressure ratio is asymmetricly distributed under the action when two trains meet,while the peak excess pore water pressure ratio is a little greater than that at the situation with one single train.