北本水电站坝基岩体剪切强度参数取值分析

Analysis on the Value Selection of Dam Foundation Rock Mass Shear Strength Parameters of Pakbeng Hydropower Station

以北本水电站的岩体抗剪强度试验数据为基础,采用Hork-Brown理论对数据进行整理及分析得出,坝基岩体与混凝土的抗剪强度主要受岩体强度控制,结构面抗剪强度主要受结构面充填物质及矿物成分控制;岩体抗剪强度的残余内摩擦角是峰值内摩擦角的0.78~0.95、残余粘聚力是峰值粘聚力的0.35~0.8,采用小值平均值拟合的数据及0.2分位值统计的结果与采用Hork-Brown理论推算的抗剪强度基本一致,说明采用岩体残余强度值为设计值是合理和安全的,但尚有一定的安全储备。

Based on the test data of the rock mass shear strength of Pakbeng Hydropower Station,the data is organized and analyzed by using Hork-Brown theory.It is concluded that the shear strength of the dam foundation rock mass and concrete is mainly controlled by the rock mass strength,and the shear strength of structural surface is mainly controlled by the filling material and mineral composition.The residual internal friction angle of rock mass shear strength is 0.78-0.95 times of the peak internal friction angle,and the residual cohesive force of rock mass is 0.35-0.8 times of the peak cohesive force.The shear strength results obtained by using the small mean value fitting parameter and the 0.2 point value statistics are basically the same as the value calculated by the Hork-Brown theory,indicating that it is reasonable and safe to use the residual strength value of the rock mass as the design value,but there is still some safety reserve.