基于三轴试验与数值模拟的大理岩破坏特征研究

为了研究深部围岩在不同围压下的力学性质与破坏特征, 对不同围压下大理岩开展了三轴压缩试验; 利用RFPA^2D数值模拟软件对大理岩开展了不同围压下应力-应变特征、强度与声发射特征等研究。结果表明, 岩样峰值应力与围压有关, 随着围压增大, 岩样逐渐由脆性破坏转为延性破坏; 岩石弹性模量随着围压增大表现出非线性增大规律; 数值模拟结果也表明, 岩样声发射现象在单轴压缩时反应强烈, 伴随围压增大, 岩样声发射特征参数逐渐趋于稳定, 围压对岩石横向应变有明显束缚作用, 降低了岩石能量释放与破坏程度。RFPA^2D数值模拟可呈现大理岩试样在不同围压下裂纹萌生、发育、汇合至试样破坏的全过程, 其模拟结果与室内试验结果吻合度较高, 验证了结论的可靠性, 可为矿山深部开采提供理论依据和现实指导。

Failure Characteristics of Marble Based on Triaxial Test and Numerical Simulation

In order to study the mechanical properties and failure characteristics of deep surrounding rocks under different confining pressures, triaxial compression tests were conducted for a marble under different confining pressures. The stress-strain characteristics, strength and acoustic emission characteristics of the marble were also studied by using RFPA^2D numerical software. The results show that the peak stress of the rock sample is related to the confining pressure. The rock sample gradually turns from brittle failure to ductile failure as the confining pressure increases, and the elastic modulus of the rock increases nonlinearly with the increase of the confining pressure. The numerical simulation results show that strong acoustic emission can be observed during uniaxial compression. With the increasing of the confining pressure, the characteristic parameters of acoustic emission of the rock samples gradually tend to be stable, and the confining pressure has an obvious binding effect on the lateral strain of the rock, which reduces the release of rock energy and the degree of damage. The RFPA^2D numerical simulation can present the whole process of crack initiation, development, convergence and failure of the marble sample under different confining pressures, with the simulation results consistent with the laboratory test results, which verifies the reliability of the conclusion. This research can provide a certain theoretical basis and practical guidance for deep mining of mines.