论文部分内容阅读
通过对煤样常规三轴试验的拟合,得到一组能够反映煤样宏观力学性质的PFC细观参数,并在此基础上制备含不同倾角预制裂隙的剪切试样,利用模拟的方法研究裂隙倾角对煤样宏观剪切力学性质的影响.通过对模拟结果分析,得到如下结论:由于拉应力最大值和拉应力的分布区域随裂隙倾角不断改变,导致裂纹萌生应力在倾角为0°~30°时呈现不断增大的趋势,在30°~75°之间呈现减小的趋势,在75°~90°之间呈现增大趋势.根据裂纹数目随应力应变曲线的变化特点,将试样的破坏过程分为3个阶段,并根据翼裂纹再次扩展到次生裂纹萌生扩展阶段对应的剪切应变大小将不同裂隙倾角试样大体分为脆性破坏试样和延性破坏试样.在对试样破坏过程分类的基础上分析了试样的最终破裂模式和次生裂纹萌生对应的剪切应变,结果表明试样破裂过程的决定因素为试样的破裂模式,并且破裂模式影响次生裂纹萌生对应的剪切应变.通过对模拟试验结果的分析,提出不同工况的支护建议.
Through the fitting of the conventional triaxial test of coal sample, a group of mesoscopic PFC parameters that can reflect the macroscopic mechanical properties of coal samples are obtained. Based on this, the shear specimens with pre-fractures with different dip angle are prepared and simulated by simulation The influence of fracture angle on macroscopic shearing mechanical properties of coal samples is analyzed.The simulation results show that the maximum tensile stress and tensile stress distribution along with the fracture angle change continuously and the crack initiation stress is in the range of 0 ° ~ 30 °, showing an increasing tendency, showing a decreasing trend between 30 ° ~ 75 ° and an increasing trend between 75 ° ~ 90 °.According to the variation characteristics of the number of cracks with the stress-strain curve, The failure process is divided into three stages, and according to the size of shear strain that the wing crack propagates again to the initiation stage of secondary crack initiation, the specimens with different fracture angles can be divided into brittle failure specimens and ductile failure specimens. The final rupture mode of the specimen and the shear strain corresponding to the secondary crack initiation are analyzed based on the classification of the specimen failure process. The results show that the rupture of the specimen is the rupture mode of the specimen, and Secondary split mode affects the shear strain corresponding to crack initiation on the analysis of simulation results, the support suggestions proposed different conditions.