富水软岩隧道施工围岩力学特性及变形研究

Study on mechanical properties and deformation of surrounding rock in water rich soft rock tunnel construction

以某富水软岩隧道施工为研究对象,采用数值模拟的方法,重点分析了考虑流固耦合作用前后隧道位移、围岩初支应力和围岩塑性区的变化规律,得到结论:考虑流固耦合作用后的最大水平位移和最大竖向位移比不考虑时分别增大了29.7%和71.1%,围岩最大拉应力和最大压应力分别增大了1.6倍和46.1%;考虑流固耦合作用后,由于水的存在,围岩的塑性区明显较不考虑时增大许多,此时围岩更容易发生屈服;高压富水隧道开挖后会增大有效应力,因此,在设计和施工时更要重点进行支护加固,防止隧道发生失稳。

Taking the construction of a water rich soft rock tunnel as the research object,using the method of numerical simulation,this paper focuses on the variation laws of tunnel displacement,initial support stress of surrounding rock and plastic zone of surrounding rock before and after considering the fluid structure coupling,and obtains the following conclusions that the maximum horizontal displacement and maximum vertical displacement after considering the fluid structure coupling are increased by 29.7%and 71.1%respectively compared with those without considering.The maximum tensile stress and maximum compressive stress of surrounding rock increased by 1.6 times and 46.1%respectively.After considering the fluid structure interaction,due to the existence of water,the plastic zone of surrounding rock is obviously much larger than that when it is not considered,and the surrounding rock is more prone to yield.The effective stress will increase after the excavation of high-pressure and rich water tunnel.Therefore,support and reinforcement should be emphasized in the design and construction to prevent the instability of the tunnel.