岩石节理在固定法向压力刚度条件下的剪切理论研究

节理在固定法向压力刚度（CNS）条件下的剪切过程比较复杂，剪切中由于剪胀的存在使得法向压力增大，而法向压力的增加又限制了剪胀的发生。根据CNS剪切过程中某一瞬时状态下法向压应力大小，以节理在该法向压应力下法向剪胀位移与剪切位移的关系为基础，建立一个楔形物理模型。通过循环迭代求得CNS剪切过程中每一步的法向压应力值，进而得到整个过程的剪切应力值。通过该模型，讨论了节理各参数对CNS剪切过程的影响，结果表明，其剪切应力值受法向压应力刚度与节理法向变形参数共同协调控制（包括单轴压缩变形及剪胀角的磨损），节理在剪切过程中越不易发生压缩变形，其剪切应力值越大。

Theoretical study of rock joints shear behavior under constant normal stiffness conditions

The shear behavior of joints was not easy to predict under constant normal stiffness(CNS) conditions.The normal compressive stress would increase during shearing when the joints dilation took place.Meanwhile the increasing of compressive stress would cause the restriction of dilation,which would finally reduce the increment of compressive stress.A simple model was presented to simulate the joints shear behavior under CNS conditions.It was based on the relationship between normal displacement and shear displacement of the joints in the shearing process,from which the normal compressive stresses in the CNS conditions were calculated iteratively and the shear stresses were obtained finally.The influences of parameters of rock joints on shear behavior under CNS conditions were also discussed.The results show that the shear stresses are determined coordinately by the constant normal stiffness and the normal deformation parameters of joints,including the uniaxial compressive deformation and the decreasing of dilation angle;and the shear stress will reach a high value if the joints are not easy to compress during CNS shearing process.