富水岩质隧道开挖稳定性分析

Stability Analysis of Water Rich Rock Tunnel Excavation

为了对富水区岩质隧道开挖的安全范围进行研究,基于弹性多孔介质和Biot-Willis理论模型,考虑开挖过程中渗透系数变化,建立隧道开挖三维流固耦合模型,并以此对重庆花阳隧道的开挖稳定性进行分析。通过不同的开挖距离(步长)将中间迭代过程中的应力结果嵌入到流体模型的孔隙水压力中,实现流固耦合作用下隧道动态开挖过程稳定性分析。结果表明:在隧道富水段,原位应力增大是由孔隙水压力产生的,距离富水段开挖前10m和开挖后30m是应力、位移发生突变的区域,突变率将近50%,在开挖富水隧道时,应在安全范围内对隧道进行加固,保持隧道的稳定性。论文成果可为隧道现场灾害治理提供参考性意见。

In order to investigate the safety range of rock tunnel excavation in water-rich areas,a three-dimensional fluid-solid coupling model for tunnel excavation was established which considering the change of permeability coefficient during excavation based on elastic porous media and Biot-Willis theoretical model.This model is then applied to analyze the stability of Huayang Tunnel in Chongqing city.Stress results from intermediate iterations was embedded into pore water pressure in the fluid model through different excavation distances(steps)which can analyze the stability of the tunnel dynamic excavation process under fluid-solid coupling.The results show that in the water-rich section of the tunnel,the in-situ stress increase is caused by the pore water pressure.The distance between 10 meters and the excavation of 30 meters the excavation of the water-rich section is the area where the stress and displacement change abruptly,and the abrupt change rate could reach 50%.The corresponding treatment plan is finally proposed,which could provide reference for on-site disaster management.