Loading method.

In order to study the mechanical response and crack evolution law of different lithologic rock bodies under different stress environments in deep stress mines, based on the deviator stress theory, the actual triaxial disturbance unloading rock test system was used to simulate the stress occurrence environment of the original rock. The mechanical characteristics of different σ2 coal rock masses were studied, and the crack evolution law of coal and sandstone under different stress environments was analyzed. The results show that the increase of σ2 inhibits the deformation in the σ2 direction of coal and sandstone, promotes the expansion and deformation in the σ3 direction, and enhances its peak strength and elastic modulus. The development characteristics of internal cracks in rock mass are directly related to the stress environment, and the increase of σ2 promotes the increase of the proportion of coal RA value, weakens the proportion of sandstone RA value, aggravates the development of coal internal shear cracks, and inhibits the development of internal shear cracks in sandstone. The larger σ2, the greater the initial AE ringing count of coal and sandstone, and the greater the AE cumulative energy when the rock mass is finally damaged. At the same time, due to the self-organizing behavior in the process of crystal failure in sandstone, the cumulative energy curve of sandstone fluctuates in a step-like manner. The ringing count and cumulative energy increase suddenly, which can predict the imminent instability and failure of the rock, and the research results can provide an experimental basis for the sudden instability of deep high-stress roadways.

为研究深部应力矿山中不同岩性岩体在不同应力环境下的力学响应与裂纹演化规律，本研究以偏应力理论为基础，采用真实三轴扰动卸荷岩石试验系统模拟原岩的应力赋存环境，针对受不同第二主应力（σ2）作用的煤岩体开展力学特性研究，并分析了煤与砂岩在不同应力环境下的裂纹演化规律。研究结果显示，σ2的增大可抑制煤与砂岩在σ2方向的变形，促进其在第三主应力（σ3）方向的扩容变形，并提升其峰值强度与弹性模量。岩体内部裂纹的发育特征与应力环境直接相关：σ2的增大可提升煤体RA值（RA value）的占比，降低砂岩RA值的占比，加剧煤体内部剪切裂纹的发育，同时抑制砂岩内部剪切裂纹的扩展。σ2越大，煤与砂岩的初始声发射（Acoustic Emission，AE）振铃计数越高，岩体最终破坏时的声发射累计能量也越大。与此同时，由于砂岩在晶体破坏过程中存在自组织行为，其声发射累计能量曲线呈现阶梯状波动特征；振铃计数与累计能量的突增可用于预判岩体即将发生失稳破坏。本研究成果可为深部高应力巷道的突发性失稳提供试验依据。