孔隙水压力作用下砂岩裂纹扩展行为的试验研究  

Experimental study of sandstone crack propagation behavior under different seepage pressures

作　　者：张黎明[1,2] 王在泉[1,2] 赵天阳 丛宇[1,2] ZHANG Li-ming;WANG Zai-quan;ZHAO Tian-yang;CONG Yu(School of Civil Engineering,Qingdao University of Technology,Qingdao,Shandong 266033,China;Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone,Qingdao University of Technology,Qingdao,Shandong 266033,China;School of Science,Qingdao University of Technology,Qingdao,Shandong 266033,China)

机构地区：[1]青岛理工大学土木工程学院,山东青岛266033 [2]青岛理工大学蓝色经济区工程建设与安全协同创新中心,山东青岛266033 [3]青岛理工大学理学院,山东青岛266033

出　　处：《岩土力学》2022年第4期901-908,共8页Rock and Soil Mechanics

基　　金：山东省自然科学基金(No.ZR2020ME099,No.ZR2020MD111);国家自然科学基金(No.52179104)。

摘　　要：为研究水力耦合作用下砂岩裂纹扩展特征,开展了不同孔隙水压和围压条件的砂岩破坏试验。结果表明:有效围压相同,随着孔隙水压力增大,脆性指标数增大,起裂应力、损伤应力和峰值应力都变小;裂纹初始体积应变变小,裂纹扩展体积应变先减小后增大,损伤应力与峰值应力对应的裂纹轴向应变扩展速率、裂纹环向应变扩展速率增加,裂纹体积应变扩展速率与孔隙水压力关系不明显。孔隙水压力相同,随着有效围压增加,起裂应力、损伤应力和峰值应力增大。起裂应力、损伤应力、峰值应力对应的裂纹轴向应变扩展速率、裂纹环向应变扩展速率和裂纹体积应变扩展速率增大。同一块砂岩特征应力点的裂纹应变扩展速率比较,裂纹轴向应变扩展速率最大,裂纹环向应变扩展速率次之,裂纹体积应变扩展速率最小。To study the characteristics of sandstone crack propagation under hydraulic coupling,sandstone laboratory tests were conducted under different seepage pressures and confining pressures.Under the same effective confining pressure,it is shown that the rock brittleness index becomes higher as the seepage pressure increases,while the crack initiation stress,the crack damage stress,and the peak stress decrease gradually.The initial volumetric strain of the crack decreases,and the volumetric strain of crack propagation decreases firstly and then increases afterward.The growth rate of the crack axial strain and the crack circumferential strain are both increasing that corresponding to the damage stress and the peak stress,however,no obvious relation is observed between the growth rate of the crack volume strain and the seepage pressure.Under the same seepage pressure,the initiation stress,damage stress,and peak stress gradually increase as the effective confining pressure increases.In addition,the growth rates of the crack axial strain,circumferential strain and volumetric strain increase gradually during deformation that corresponds to the crack initiation stress,damage stress and peak stress,respectively.When comparing the different growth rates of crack strain for a tested sandstone specimen,it is found that the strain growth rates have the following order:the crack axial strain>the crack circumferential strain>the crack volume strain.

关 键 词：水力耦合 特征应力 裂纹扩展速率 

分 类 号：TU454[建筑科学—岩土工程]