论文部分内容阅读
地下洞室围岩在软岩地质条件下会产生流变效应,考虑“围岩—喷锚支护”系统的整体力学效应,在西源模型的基础上,提出了以塑性屈服函数及应力水平和长期强度大小关系为两个控制参数的双开关西源模型,建立包含流变时间、应力水平和塑性屈服函数等在内的粘弹性应变增量和粘塑性应变增量表达式;岩石未进入塑性屈服状态只考虑粘弹性应变增量,进入屈服状态后就应考虑粘塑性应变增量。将建立的非线性粘弹塑性流变模型编入三维弹塑性有限元程序,利用初应变法将应变增量转化为该应力水平下单元虚拟节点荷载,考虑锚杆、锚索的加固效应和喷层提供的支护抗力,最终求解围岩塑性区范围及其应力、应变和位移。以某抽水蓄能电站地下厂房洞室群为例,分析其“围岩—喷锚支护”系统30d流变过程中围岩塑性区、变形位移及锚杆应力变化规律,结果表明所建非线性粘弹塑性模型能较好地分析地下洞室的流变效应,可为工程设计施工提供合理建议。
The surrounding rock of underground cavern will produce rheological effect under soft rock geological conditions. Considering the overall mechanics effect of surrounding rock-spray-anchor supporting system, on the basis of Xiyuan model, the plastic yield function The relationship between stress level and long-term strength is a two-switch west-source model with two control parameters. Visco-elastic strain increment and visco-plastic strain increment expression including rheological time, stress level and plastic yield function are established. Plastic yield state only consider viscoelastic strain increment, after entering the yield state should consider the viscoplastic strain increment. The established nonlinear viscoelasto-plastic rheological model is incorporated into the three-dimensional elasto-plastic finite element program. The initial strain method is used to convert the strain increment into the unit virtual node load under this stress level. Considering the reinforcement effect of bolt and anchor cable, Layer to provide the support resistance, and finally solve the plastic area surrounding rock and its stress, strain and displacement. Taking the caverns in underground powerhouse of a pumped storage power plant as an example, the plastic zone, plastic deformation and displacement of anchor rock during the 30d rheology of “surrounding rock - shotcrete and anchor supporting system” are analyzed. The results show that The nonlinear viscoelastic-plastic model can well analyze the rheological effect of underground caverns and provide reasonable suggestions for engineering design and construction.