【摘要】 基于在伺服试验机上获得的不同围压下断续预制裂隙大理岩体积应变-轴向应变全程曲线,分析了围压对断续预制裂隙大理岩扩容特性的影响规律。结果表明,完整和断续预制裂隙大理岩裂纹损伤阈值随着围压的增加均近似呈线性增大,而且裂纹损伤阈值对围压的敏感性低于峰值强度;同等围压下,粒径较小的中晶大理岩具有较高的裂纹损伤阈值;完整或断续预制裂隙大理岩的长期内摩擦角均显著低于瞬时内摩擦角值,但长期黏聚力的降低幅度与裂隙分布密切相关;完整或断续预制裂隙大理岩的峰值强度越高,相应的裂纹损伤阈值也越大,且两者之间具有较好的线性关系。研究结论对于岩石工程设计和数值分析时断续节理裂隙岩体力学参数选取具有一定的参考价值。更多还原

【Abstract】 Based on the obtained volumetric-axial strain curves of marble with pre-existing fissures under different confining pressures,the effect of confining pressures on dilatancy behavior of marble with pre-existing fissures is analyzed.The results show that the crack damage thresholds of intact and pre-cracked marble all increase linearly with the confining pressures,and that the sensibility of the crack damage thresholds to the confining pressures is lower than that to the peak strength.Under the same confining pressure,the medium marble with smaller grain sizes has higher crack damage threshold.The long-term internal friction angles of intact and pre-cracked marble are lower distinctly than the short-term,but the reducing extent of long-term cohesion is closely related to fissure geometry.The higher the peak strength of intact or pre-cracked marble,the larger the corresponding crack damage thresholds.The peak strength of intact and pre-cracked marble has a good linear relation with the crack damage thresholds.The conclusions are significant for the choice of mechanical parameters of rock mass with jointed fissures when carrying out engineering design and numerical simulation.更多还原