丰宁抽水蓄能电站地下厂房围岩地质条件复杂,软弱夹层和不利结构面组合较多。在长期载荷的作用下,这部分岩体容易发生流变。电站运营时,机械振动、水流冲击等扰动因素加速了流变进程,使岩体稳定性变差,对电站的安全运营极为不利。本文选取12 条蚀变带作为主要研究对象,通过室内流变扰动效应试验,获得厂房蚀变带岩体的基本物理参数,分析出扰动敏感阈值。并根据所测参数及相关地质资料,建立地下厂房三维数值模型。利用ABAQUS 有限元软件分析地下厂房位移场、应力场及塑性区分布和厂房12 条蚀变带全过程位移变化的规律。研究表明:地下厂房整体位移场、应力场、塑性区都在可控范围内。12 条蚀变带流变趋势呈减速流变趋势,蠕变总位移为5~12 mm。在扰动荷载作用下,含蚀变岩的围岩长期稳定性可以得到保证。

The geological conditions of the surrounding rock of the underground powerhouse of FengningPumped Storage Power Station are complex,and there are many combinations of weak interlayers and unfavor⁃able structural planes. Under the action of long-term load,this part of rock mass is prone to rheology. Duringthe operation of the power station,disturbance factors such as mechanical vibration and water flow impact ac⁃celerate the rheological process,which deteriorates the stability of the rock mass and is extremely unfavorable tothe safe operation of the power station. In this paper,12 alteration zones are selected as the main research objects. Through the indoor rheological disturbance effect test,the basic physical parameters of the rock mass inthe alteration zone of the plant are obtained,and the disturbance sensitive threshold is analyzed. According tothe measured parameters and related geological data,a three-dimensional numerical model of undergroundpowerhouse is established. ABAQUS finite element software is used to analyze the displacement field,stressfield and plastic zone distribution of underground powerhouse and the law of displacement change in the wholeprocess of 12 alteration zones of underground powerhouse. The research shows that the overall displacementfield,stress field and plastic zone of the underground powerhouse are within the controllable range. The rheo⁃logical trend of 12 alteration zones shows a deceleration rheological trend,and the total creep displacement is 5~ 12 mm. Under the action of disturbance load,the long-term stability of surrounding rock with altered rockcan be guaranteed.