柘溪水电站开关站边坡变形分析

Slope Deformation Analysis of Switch Station of Zhexi Hydropower Station

柘溪水电站扩机过程中,为保证扩机厂房东端开关站边坡稳定,采用截面积分别为2.5 m×8 m和4 m×8 m的挡土墩进行支护。在挡土墩的施工开挖过程中,因为挡土墩的截面积比较大,加之边坡填渣的性状差,开关站边坡监测下沉变形较大,且变形速度加快,引起开关站线架上外侧电缆被拉直。为评估在整个挡土墩施工期间,开关站边坡及地表的变形状态、变形量级、变形影响范围,在充分利用现有工程地质资料和试验结果的基础上,建立挡土墩开挖支护的三维数值模型,根据施工开挖期间得到的边坡上外观监测变形信息,采用FLAC 3D软件,设计了12组参数样本,通过位移反分析的方法获得了开关站边坡内人工堆积物的变形参数,在此基础上进行挡土墩开挖施工过程仿真模拟,通过计算分析,得到了一些对设计和施工都有意义的结果。

During the expansion of Zhexi Hydropower Station, in order to support the eastern slope of the power station, a row of anti-slide piles with sectional area 2.5 m × 8 m and 4 m × 8 m were applied. The excavation of the piles produced much and fast deformation of the slope and ground surface due to the large sectional area and the bad quality of the filling. Base on the available engineering geological data, test results and monitoring data of subsidence deformation, a 3 - D numerical model of anti-slide pile supporting was set up to evaluate the mode, level and impact of the deforma- tion. And then FLAC3D program were used to establish 12 parameter samples to make back-analysis to get the deformation parameters of the man-made deposit in the field. Then a simulation of the excavation of the piles was made. At last some results proved to be benefit for engineering design and construction were obtained by calculation and analysis.