引水隧洞初期支护及其施加时机对围岩稳定性的影响

Effect of Primary Support and Application Timing on Surrounding Rock Stability of Diversion Tunnel

为研究初期支护对水工隧洞开挖后围岩稳定性的影响,以Hypermesh平台建立有限元模型,采用ABAQUS作为计算和后处理软件,分析了裸洞开挖以及在不同时机施加初期支护时围岩的变形、应力和塑性破坏区,探究了工字钢采用等效模拟的可行性。结果表明,采用等效参数法模拟钢拱架合理,初期支护可有效提高围岩的稳定性,且随着施加时机的提前,围岩稳定性越好,但同时支护结构的受力会越大。为减轻初期支护的负荷,需要充分发挥围岩自身的承载能力。因此,合理选择最佳施作时机十分重要。

To study the influence of primary support on the stability of surrounding rock after excavation of hydraulic tunnel,the finite element model was established with Hypermesh platform.Using ABAQUS as the calculation and posttreatment software,the deformation,stress and plastic failure zone of surrounding rock without primary support and under different supporting conditions were analyzed,and the feasibility of equivalent simulation for I-beam was investigated.The results show that it is reasonable to use equivalent parameter method to simulate the steel arch,and the primary support can effectively improve the stability of surrounding rock;With the advance of the application time,the stability of surrounding rock is better,but the stress of support structure is greater.In order to reduce the load of initial support,it should be given full play to the surrounding rock’s self-supporting capacity.Therefore,the best supporting time should be selected reasonably.