基于3DEC节理岩体隧道开挖与支护的数值模拟

隧道在穿过节理裂隙较发育的地质环境时，地下水与支护条件等因素会对隧道开挖后围岩的稳定性产生影响。因此，以国内某山岭高速公路隧道为背景，基于离散元理论，考虑裂隙水压力作用，分析了砂浆锚杆与混凝土衬砌等支护条件在隧道开挖后对围岩稳定性的影响，并基于3DEC软件，对裂隙岩体隧道的开挖与支护进行了数值模拟。模拟结果表明：地下水对裂隙岩体隧道的开挖与支护影响较大，有地下水的裂隙岩体隧道开挖较无地下水的围岩整体与局部位移均增加了2~3倍；在有无裂隙水两种工况下，选择合理的支护手段均能使围岩位移量减小20%~32%。

Numerical Simulation of Jointed Rock Mass Tunnel Excavation and Support Based on 3DEC

In view of the fact that such factors as groundwater and supporting conditions will affect the stability of surrounding rocks after tunnel excavation in the process of the tunnel passing through the geological environment with developed joints and fissures, with a case study of a mountain highway tunnel in China as the background, based on the discrete element theory, an analysis has been made of the influence of such support conditions as mortar anchor and concrete lining on the stability of surrounding rocks after the tunnel excavation, with the effect of fracture water pressure taken into consideration, followed by a simulation test of the excavation and support of tunnel in fractured rock mass by using 3DEC software. The simulation results show that groundwater exerts a great influence on the excavation and support of the tunnel in fractured rock mass, with the overall and local displacement of the tunnel in fractured rock mass with groundwater 2~3 times higher than that of the tunnel without groundwater, and that the displacement of surrounding rock can be reduced by 20%~32% by adopting reasonable support methods under two different working conditions with or without the fracture water.