某抽水蓄能电站地下厂房洞室群三维有限元稳定性分析

Three-dimensional Finite Element Stability Analysis of the Underground Cavern Group in a Pumped Storage Power Station

为了了解抽水蓄能电站地下厂房洞室群开挖支护后围岩的稳定性,以某抽水蓄能电站地下厂房洞室群为例,采用隐式弹粘塑性本构关系,建立三维有限元模型,对比分析地下洞室群毛洞工况、锚杆+锚索+衬砌联合支护工况及支护参数优化后围岩的变形、应力场分布及D-P点安全系数。结果表明:采用锚杆+锚索+衬砌联合支护的方式可以有效减小地下洞室群围岩的位移量,提高D-P点安全系数,使应力分布更为均匀,围岩的稳定性更好。锚杆长度在6m~8m范围变化及锚索预应力变化对围岩的变形、应力以及D-P点安全系数的影响不显著,但是对围岩局部有一定的影响,施工过程中应动态优化调整。

In order to understand the stability of surrounding rock after excavation and support of underground powerhouse cavern group in pumped storage power stations,a certain underground carvern group of pumped storage power station was taken as an example.Threedimensional finite element model was established by using the implicit elastoplastic constitutive relationship.The deformation,stress field distribution,and the safety factor of the surrounding rock under different conditions were analyzed.The initial excavation condition,the condition with combined support of rock bolts,anchor cables and lining were compared.And the condition of optimizing support parameters was also analyzed.The results indicate that the combined support of rock bolts,anchor cables and lining could reduce the displacement of the surrounding rock in the underground cavern group,increase the D-P point safety factor,and create a more uniform stress distribution.Which improved the stability of the surrounding rock.The variation in the length of rock bolts within the range of 6 to 8 meters and the change in anchor cable prestressing have negligible impacts on the deformation,stress,and D-P point safety factor of the surrounding rock.But they do have some influence on local areas of the surrounding rock,thus dynamic optimization adjustment should be made during construction.