考虑流固耦合效应的水下隧道开挖工序模拟

采用FLAC3D数值方法并考虑流固耦合效应对静水平面17 m下隧道施工进行数值模拟，比较分析了不同工法开挖的围岩渗流、位移、应力及塑性区的变化。计算结果表明，CD法需注重隧道拱部预注浆堵水加固，台阶法需加强全断面预注浆堵水加固；考虑流固耦合影响后，隧洞围岩压力相对减小30%；且不同工法开挖〖JP2〗情况下，流固耦合效应对隧道支护结构的扁平效应影响不同；拱顶与拱脚是水下隧道施工应重点关注的部位。

Simulation Excavation Procedure of Submerged Tunnel Considering Fluid-solid Coupling Effect

Considering fluid solid coupling effect,FLAC3D numerical method is adopted to simulate the construction of tunnel at 17 meters below still water horizontal plane.The change of plastic zone,seepage flow,displacement and stress for surrounding rocks excavated by different methods is analyzed.Calculated results show that CD method should emphasize consolidating the pre-grouting and water plugging of tunnel arch while the bench method on reinforcing that of full section;under the effect of fluid solid coupling,the stress of rocks surrounding in tunnel reduces 30% relatively;the influence of fluid solid coupling on the flat effect of the tunnel support structure will be different under the different excavation methods;underwater construction of tunnel often concerns more about the vault and springing.