裂隙对含孔洞砂岩力学及损伤演化特征的影响

Effect of fissure on mechanical and damage evolution characteristics of sandstone containing hole defect

为研究裂隙对含孔洞岩体力学及损伤演化特征影响,利用颗粒流模拟程序,对存在不同裂隙形态的含孔洞岩样在单轴压缩下的力学性质进行数值试验研究,分析岩样破裂与力学特征随裂隙形态的变化情况,对其损伤演化特性进行探讨。研究结果表明:裂隙的存在会改变原有含孔洞岩样沿孔洞贯通的破坏模式,大多数岩样会形成贯通裂隙的主破裂带;但当裂隙存在于距原主破裂带较远,且倾角较大或长度较小时,岩样依沿孔洞形成主破裂带;岩样的峰值应力随裂隙距孔洞距离或裂隙倾角的增大而增大,随裂隙长度的增大逐渐减小;含孔洞岩样周边存在距孔洞距离越远,长度越大的裂隙,在相同应变下损伤越小;含孔洞岩样的损伤修正系数取值为0.77～0.90。

In order to study the effect of fissure on the mechanics and damage evolution characteristics of rock containing hole defect, the mechanical behavior of sandstone containing hole defect with different fissure morphologies was tested under uniaxial compression conditions by using the particle flow simulation program. The fracture and mechanics characteristics of rock samples were analyzed with the changes of fissure morphology. The damage evolution characteristics of rock samples were discussed. The results show that the presence of fissures will change the fracture pattern of the original rock sample containing hole defect along the hole defect and most of the rock samples will form the main fractured by the fissure. For fissure that is relatively far away from the original main fracture belt and has a larger angle or a smaller length, the rock sample is still fractured along the hole defect. The peak stress increases with the increase of the distance from the fissure to the hole defect and it increases with the increase of the fissure angle. The peak stress of the rock sample gradually decreases with the increase of fissure length. For fissure that is further away from the hole defect and has greater length, the damage is smaller at the same strain. The damage correction coefficients are 0.77-0.90 for rock samples containing hole defect.