乌东德水电站左岸尾水出口陡倾顺向坡变形影响因素分析

 乌东德水电站左岸尾水出口正面边坡为典型陡倾顺向坡，在施工期出现了2次变形。以工程地质条件分析为基础，以变形监测资料和声波检测资料分析为主要手段，辅以三维数值模拟计算，对其变形与边坡结构、坡脚隧洞、开挖爆破、坡内小断层、卸荷松弛的关系进行研究，进而对边坡变形的影响因素进行分析。研究认为，该边坡变形主因为顺向坡切脚，此外，脚部紧凑大断面隧洞挖空和超标准爆破扰动，在较大程度上加剧了边坡的变形，坡面出露的小断层对断层附近坡体变形加剧有一定影响。提出在脚部有大断面隧洞开挖的顺向坡施工中，洞坡交叉部位的隧洞开挖应以支护后边坡稳定为前提，再进行隧洞的分层开挖，另外，施工爆破与边坡支护在顺向坡施工过程中亦应予以高度重视与特殊控制。研究成果丰富了顺向坡稳定性研究的工程实例，为工程本身的支护设计及开挖施工提供了重要的技术支持，亦为类似工程提供可以借鉴的经验与指导。

Factors influencing deformation of steep consequent slopes at the tail water outlet on the left bank of Wudongde hydropower station #br#

The slope located at the exit of left tail water tunnel of Wudongde hydropower station is a typical bedding slope with a high dip angle，and the deformation occurred in two stages during the excavation. The influences of the slope structure，the excavation at slope toe，the engineering blasting，the fault and the unloading on the slope deformation were studied with the field monitoring and the numerical simulation. The results show that the main reason of deformation is the cutting excavation at slope toe. In addition，the excavation of a tunnel with large cross section at slope toe and the excessive blasting increase the deformation. The small fault in the slope also affects the slope deformation to some extent. Therefore，it was suggested that excavation should be carried out after the slope supporting at the intersection region of tunnel and slope.