层理压剪特性及裂纹沿层与穿层破坏数值模拟及其机理研究

针对岩石工程中的节理缺陷，基于统计损伤理论，对含裂隙及层理情况下的小尺寸试样进行了单轴压缩数值模拟。结果表明: 不含预制裂纹的节理模型裂隙顺着节理产生，含裂隙及节理模型裂隙沿预制裂纹尖端及节理产生，仅含预制裂隙模型裂隙沿预制裂纹尖端产生; 节理倾角较小时，节理发生剪切破坏，预制裂隙的翼裂纹主要发生穿层破坏，节理倾角较大时，节理发生拉伸破坏，预制裂纹的翼裂纹主要发生沿层破坏，且靠近预制裂纹的节理破坏更加剧烈; 随着节理倾角的增大，峰值荷载先减小后增大，当节理倾角为 45°时试样的峰值荷载最小，含预制裂纹及节理下的模型峰值强度最低，仅含节理的模型峰值强度较大，仅含预制裂隙下的模型峰值强度最高。基于声发射规律推导了层理压剪损伤过程的本构方程，结合数值模拟结果，得到加载过程中岩样的损伤变化一共分为四个阶段，即线弹性变形阶段、裂纹萌生阶段、裂纹加速扩展阶段及损伤平稳发展阶段。同时，讨论了层理裂隙沿层及穿层破坏的理论解释，认为层理抗拉强度及倾角是影响裂隙的沿层及穿层破坏的关键因素。

Numerical simulation and mechanism study on compression-shear characteristics of rock stratification and layer-along and layer-through fractures of crack

Aiming at joint defects in rock project，a numerical simulation of uniaxial compression is made on the small-sized specimen with fissure and joint based on the relevant statistical damage theory． The result shows that the fissure of the joint model without prefabricated crack occurs along the joint and the fissure of the model with fissure and joint occurs along the tip of the prefabricated crack and the joint，while the fissure of the model only with prefabricated crack occurs along the tip of the prefabricated crack． When joint dip-angle is less，the shear fracture is to be taken place from the joint and the layer-through fracture mainly occurs from the wing crack of the pre-fabricated crack，while tensile fracture occurs from the joint and the layer-along fracture mainly occurs from the wing crack of the pre-fabricated crack along with the more intensive joint failure near the pre-fabricated crack when joint dip-angle is larger． Following with the increase of the joint dip-angle，the peak load decreases at first and then increases． When joint dip-angle is 45°，the peak load of the specimen is the least along with the lowest peak strength of the model with pre-fabricated crack and the joint，while the peak strength of the model with joint is larger and the peak strength of the model only with the pre-fabricated crack is the largest． The constitutive equation of the compression-shear damage process is derived according to the relevant acoustic emission law，and then the four phases of the damage variation of the rock specimen during the loading process are obtained in combination with the numerical simulation results，which are the linear elastic deformation phase，the crack initiation phase，the crack accelerated propagation phase and the damage steady development phase． Meanwhile，the theoretical explanation of both the layer-along and the layer-through rock stratification fractures are discussed，from which it is considered that the rock stratification tensile strength and dip-angle are the key factors to affect the layer-through and the layer-along fractures．