狮子洋隧道洞口列车振动流固耦合分析

Fluid-structure Interaction Analysis on Train Vibration at the Portal of Shiziyang Tunnel

根据车辆-轨道耦合模型,采用弹性地基梁板模型,得到列车轨下激振力。按广深港高速铁路狮子洋盾构隧道洞口资料,建立精细的三维数值模型,通过FLAC3D软件对列车荷载引发的隧道动力响应进行了数值模拟,分析了列车振动作用下狮子洋隧道洞口水-土耦合规律。结果表明:在列车振动荷载作用下,孔隙水压力增长区域位于隧道周边的一定范围,主要分布在隧道底部地层,在左右两隧道之间的隧道下方地层,超孔隙水压力值最大;地层受振位移响应等值线呈倒钟状分布,隧道上方影响范围大,且衰减缓慢,隧道下方影响范围小,且衰减迅速;管片左侧近域地层位移响应最大,列车振动对相邻隧道附近地层的影响不明显,其位移值远远小于左侧的地层位移。

According to vehicle-track coupling model, the sub-rail exciting force of train is obtained with beam-plate model on the elastic foundation. Depending on the data at the portal of shielded Shiziyang Tunnel of Guangzhou-Shenzhen-Hong Kong Express Rail Link, the accurate 3D numerical model is established; the dynamic response of the tunnel caused by train load is numerically simulated with FLAC3D software and the water-soil coupling law under train vibration at the portal of Shiziyang Tunnel is analyzed. The results show that under vibrating load of train, the area with increasing pore water pressure is within certain scope around the tunnel mainly located at the bottom stratum of the tunnel and the maximum excess pore water pressure exists at the lower stratum of the tunnel between left and right tunnels ; the displacement response isoline of stratum vibration presents the distribution like a inverse shell with large influenced area at the upper part of the tunnel damping slowly and small influenced area at the lower part of the tunnel damping quickly; there has maximum displacement response at the close stratum on the left of the segment, and the train vibration has little influence on the stratum close to the adjacent tunnel with the displacement value far less than that of left stratum.