某水电站厂房洞室群围岩点荷载强度试验成果分析及利用研究

Study on analysis and utilization of result from point-load strength experiment on surrounding rock of cavern group for powerhouse of a hydropower plant

通过厂房地下洞室群围岩点荷载试验,获得了洞室不同深度位置岩石点荷载强度值,试验发现各平洞点荷载强度随洞室深度变化呈现明显的波动性变化特征。研究表明,围岩岩性、断层以及岩石微观结构等是影响岩石点荷载强度的主要因素。其中,围岩中普遍发育的矿物定向排列是导致点荷载强度波动性变化的最主要因素。最后,通过与实测单轴抗压强度比较,得出当岩石单轴抗压强度大于60 MPa时,宜采用成都理工大学推荐公式换算单轴抗压强度,当单轴抗压强度小于60 MPa时,宜采用水利水电规范推荐的转换公式计算岩石单轴抗压强度。

Through the point-load experiment on surrounding rock of underground cavern group of powerhouse,the point-load strength values of the rock at different depths of the caverns are obtained; from which it is found out that the point-load strengths of all the caverns present obvious fluctuated change characteristics along with the change of the depth. The study shows that the main factors to impact the point-load strength of the rock are lithology of surrounding rock,fault,microstructure of the rock,etc.,in which the mineral oriented arrangement generally developed in the surrounding rock is just the most important factor that leads to the fluctuated change of the point-load strength. Finally,it is obtained through the comparison with the measured uniaxial compressive strength that the formula recommended by Chengdu University of Technology is appropriate to be adopted for converting the uniaxial compressive strength,when the uniaxial compressive strength of the rock is larger than 60 MPa,while the conversion formula recommended by the relevant technical specifications of water conservancy and hydroelectric engineering is suitable to be used for calculating the uniaxial compressive strength of the rock,when the uniaxial compressive strength of the rock is less than 60 MPa.