张河湾抽水蓄能电站地下厂房系统开挖监测分析

张河湾抽水蓄能电站装机4台,单机容量250MW。地下厂房系统由主副厂房、主变及开关室、母线洞等组成。厂房系统开挖后,监测到围岩位移迅速增大,空间位移表现明显,围岩位移和应力一般在支护后变化逐渐趋缓;围岩位移和锚杆应力曲线呈台阶式分布,从围岩位移变化、锚杆和锚索应力变化来看,厂房与主变室的交叉洞口处,变形较大,厂房上游拱座处受力较为复杂,变形也较大。说明开挖对围岩的位移影响很大,施工中支护必须及时跟进。

Analysis on the Excavation Monitoring of Underground Powerhouse of Zhanghewan Pumped-storage Power Plant

Zhanghewan Pumped-storage Power Plant has four generating units with the installed capacity of 250 MW each. It underground powerhouse is composed of main and auxiliary powerhouses, main transformer chamber and swithyard and busbar tunnel, etc. After the excavation of powerhouse system, we monitored that the displacement of surrounding rock increases quickly and its space displacement is obvious. The displacement and stress vary gently after the completion of supporting. The curves of displacement of surrounding rock and stresses of anchorage bars is in terrace distribution. The deformation in the crossing hole between the main powerhouse and main transformer chamber is bigger, and duo to complex stresses conditions of the upstream arch abutment of powerhouse, its deformation also is big. All these shows that the excavation will bring big effect on the displacement of surrounding rock so that the supporting should be made timely in the construction.