叶巴滩地下厂房布置方案选择与围岩稳定分析

Selection of Layout Scheme and Stability Analysis of Surrounding Rock in Yebatan Underground Powerhouse

叶巴滩水电站地下厂房区域实测最大地应力37. 57 MPa,处于高至极高地应力区,加之厂房区域地质结构面复杂,导致地下厂房尾调室选型和布置方案的选择成为工程设计难点。为了选择出合适的地下厂房布置形式,对拟比选的圆筒式尾调室,以及长廊式尾调室两种地下厂房方案展开三维非线性有限元分析。研究表明:断层F2、F4、f85和f9对圆筒式尾调室方案更为不利,开挖完成后长廊式尾调室方案能够更好的限制塑性破坏区的发展,加之长廊式方案中断层F2对主厂房仅仅切割了安装间底部高程,而圆筒式方案中,断层F2贯穿主厂房1#机组段,对主厂房围岩稳定性更为不利。长廊式尾调室方案洞周应力和围岩稳定状态较圆筒式尾调室方案更佳,建议选择长廊式尾调室方案。

The maximum in-situ stress measured in the underground powerhouse of Yebatan hydropower station is37. 57 MPa,and it is in a region of high to extremely high stress. In addition,the plant area is cut by multiple geological structure surface. Therefore,the choice of the tailrace surge tank and layout of the underground powerhouse is a difficult problem. In order to choose the appropriate underground plant layout,three-dimensional non-linear finite element analysis was carried out for the proposed program of cylinder-type surge tank and program of corridorstyle surge tank. The research shows that the fault F2,F4,f85 and f9 are more unfavorable to the program of corridor-style surge tank. After the excavation,the program of corridor-style surge tank can better limit the development of plastic damage zone. In addition,In the program of corridor-style surge tank,only the bottom height of the installation room was cut by F2. In the program of cylinder-type surge tank,F2 through the main workshop of the group,more unfavorable to the stability of surrounding rock of main powerhouse. The stress and stability of the surrounding rock in program of corridor-style surge tank are better than those in program of cylinder-type surge tank,therefore program of corridor-style surge tank is recommended.