静应力下结构面扰动变形破坏过程试验研究

Disturbance Deformation and Failure Process of Joints Under Stress

结构面的剪切变形特性通常决定着围岩体的整体稳定性。为探究结构面的扰动剪切失稳特性,采用不同起伏角度及材料的对称规则齿形结构面试件,开展一定初始静应力下的扰动失稳试验。根据工程现场易获取的基本参数,如峰值剪切强度和峰值剪切位移,将结构面分为低强低脆高延性、高强高脆高延性、高强高脆低延性3种类型,相较于准静态荷载工况,扰动工况下含齿结构面的峰值剪切强度均降低明显,但峰值剪切位移相差不大。低强低脆高延性结构面在不同应力路径下均无明显应力降,为不易致灾的类型;高强高脆低延性结构面的峰值强度高,累积不可逆位移量小,峰后跌落大,较高延性结构面更易导致失稳。

The shear deformation characteristics of joints usually determine the overall stability of the surrounding rock mass.To investigate the shear instability characteristics of joints,disturbance shear tests under different initial stresses were carried out on symmetrical regular dentate specimens with various undulation angles and materials.According to the basic parameters easily obtained from the engineering site,such as peak shear strength and displacement,the joints can be classified into 3 types,that is,"low strength,low brittleness and high ductility","high strength,high brittleness and high ductility"and"high strength,high brittleness and low ductility".The peak shear strength of the dentate joints under disturbance conditions decreases significantly,but the peak shear displacement does not differ much,compared with the quasi-static condition.The"low strength,low brittleness,high ductility"joints are the non-catastrophic types with no significant stress dropping under different stress paths.The"high strength,high brittleness,low ductility"joints exhibit higher peak strength,smaller cumulative irreversible displacement and larger post-peak dropping,which are more prone to instability than the"high strength,high brittleness,high ductility"joints.