受断层影响,在断层上盘开挖与下盘开挖时具有不同的岩移机理。采用理论和数值分析的方法分别对陡倾断层上下盘开挖这两种工程状态下的岩移机制进行了研究,结果表明:当陡倾断层位于开挖引起的岩体变形的拉张区时,不论是在断层上盘开挖还是下盘开挖,都会使垂直断层面产生附加张应力,使其抗剪强度减小,在自重体积力作用下总会表现出具有正断层方式的错动,在地表以断层陡坎或台阶状的地貌形态出现,向下到断层“活化”——错动段的下限,错距逐渐减少到零。
Influenced by faults, the mechanism of rock movement was different due to the underground excavation in hangingwals and footwalls of faults. Theoretical and numerical methods were used under two construction states of underground excavation in hangingwalls and footwalls of faults. It was indicated that when the steep faults in the tensile deformation region were incurred by underground excavation, no matter the excavation in hangingwalls or that in footwalls of the faults, there would be additional tensile stress on the vertical fault plane and the shear strength decreased, showing the characteristics of normal fault slip. This phenomenon would appear on the ground surface in the form of fault escarpment, and down to the fault "activation" the lower limit of fault slip section where the fault throw gradually reduced to zero.