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结合室内单轴试验和颗粒流与Fish语言程序对杨村矿煤岩进行了不同围压组合试验,研究双向不等围压煤岩的强度、能量演化机制,并基于能量原理导出能量强度准则。结果表明:随围压比增大,煤岩屈服段对应应变幅宽先增后减,峰后软化段应力降明显,残余强度减小;可释放弹性应变能随应变增加在峰值前不断增大,但增速越来越小,峰后初期快速减小,然后保持较低水平;随围压比增大,煤岩在较大轴向应变下出现内部损伤,高围压比下峰前一定应变范围吸收的能量全部用于内部损伤裂隙形成和扩展所需的表面能,揭示了高围压比要比低围压比煤岩破坏时内部损伤程度严重;高围压比煤岩在较大第一、第二主应力作用下峰后弹性应变能释放更加容易;煤岩弹性储能极限与围压比存在线性变化规律,将弹性储能极限与能量演化结合导出能量强度准则,准则方程包含岩性常数和3个主应力,考虑了岩石破坏的综合因素,计算精度比Hoek-Brown准则和Drucker-Prager准则更具优势,能很好地表达岩石强度特性。
Combining with the indoor uniaxial test and particle flow and Fish language program, different confining pressure combinations of coal and rock in Yangcun coal mine were carried out to study the strength and energy evolution mechanism of unequal confined coal and rock. The energy intensity criterion was derived based on energy principle. The results show that with the increase of the confining pressure ratio, the corresponding strain amplitude increases first and then decreases with the increase of strain, and the stress decreases sharply after softening and the residual strength decreases. The releaseable elastic strain energy increases with increasing strain before the peak value , But the growth rate is getting smaller and smaller, decreasing rapidly in the early post-peak period and then keeping a low level. With the increase of the confining pressure ratio, the coal rock has internal damage under large axial strain, The energy absorbed in the strain range is all used for the surface energy required for the formation and propagation of the internal damage fracture, revealing that the internal damage degree is serious when the high confining pressure ratio is lower than the confining pressure ratio and the coal rock is damaged. The post-peak elastic strain energy release under the influence of the first and second principal stresses is easier. The elastic energy storage limit and the confining pressure ratio of coal rock exist linear variation. The elastic energy storage limit and energy evolution are combined to derive the energy intensity criterion. The criterion equation contains Lithologic constants and three principal stresses. Considering the comprehensive factors of rock failure, the calculation accuracy has more advantages than Hoek-Brown criterion and Drucker-Prager criterion, and can well express the rock strength characteristics.