基于分层计算的层间剪切带原位变形试验研究

由于含层间剪切带复合岩体的非均匀性,传统的承压板变形试验只能得到复合岩体的综合模量,而无法准确得到层间剪切带的变形参数。介绍了黄河中游红色碎屑岩地区某大型水利枢纽工程坝址区层间剪切带的发育特征,选择典型勘探平硐进行刚性承压板中心孔法原位变形试验,在预留上部保护岩层条件下,通过在中心孔内设置不同深度的液压锚头,直接得到复合岩体、层间剪切带上下缘岩体的压力-变形关系曲线。利用推导的深部岩体压缩变形公式,分别计算其变形参数。根据分层计算原理,利用层间剪切带上缘岩体和下缘岩体变形差值计算得到层间剪切带的等价变形参数。研究结果表明,层间剪切带的变形参数低于上下缘岩体及复合岩体,其等价变形模量为0.72GPa,等价弹性模量为1.41GPa。

Study on In-situ Deformation Test of Interlayer Shear Zone Based on Divided Layer Calculation

Because of unhomogeneity of composite rock mass with interlayer shear zone, there is a synthetical modulus of composite rock mass can only be obtained by traditional pressure-bearing plate test, but the deformation parameters of interlayer shear zone cannot be obtained. The characters of interlayer shear zones at some dam sites of big hydraulic project in red clastic area of Yellow River middle reaches were introduced. A rigid pressure-bearing plate in-situ experiment with central borehole was conducted at some typical prospect adit. The relationship curves between pressure and deformation of composite rock mass, upper rock mass and lower rock mass of interlayer shear zone were directly obtained by arranging different deep hydro-anchor heads under beforehand remaining upper protecting rock. Their deformation parameters are calculated by the deduced compressive deformation formula of deep rock mass. According to divided layer calculation, the equivalent deformation parameters of interlayer shear zone are calculated by the difference between upper rock mass and lower rock mass of interlayer shear zone. Research results show that the deformation parameters of interlayer shear zone are lower than those of upper rock mass, lower rock mass and composite rock mass. Its equivalent deformation modulus is 0.72GPa, and its equivalent elastic modulus is 1.41GPa.