岩石倾斜裂隙与水平裂隙扩展贯通试验及数值模拟研究  

Experimental study and numerical simulation of inclined flaws and horizontal fissures propagation and coalescence process in rocks

作　　者：魏超 朱维申[1] 李勇[1,2] 王书刚 董振兴[1] 蔡卫兵 WEI Chao;ZHU Wei-shen;LI Yong;WANG Shu-gang;DONG Zhen-xing;CAI Wei-bing(Geotechnical and Structural Engineering Research Center,Shandong University,Jinan,Shandong 250061,China;School of Qilu Transportation,Shandong University,Jinan,Shandong,250002,China)

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]山东大学齐鲁交通学院,山东济南250002

出　　处：《岩土力学》2019年第11期4533-4542,4553,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金项（No.41672281,No.51579140,No.51879149）;山东大学交叉学科基金（No.2017JC001）;山东大学齐鲁交通学院自由探索项目（No.2019B47_1）~~

摘　　要：采用最新配置的水泥砂浆材料,通过在试件中布置倾斜裂隙和水平裂隙,开展了单轴和双轴条件下的压缩试验,详细分析了不同加载条件下试件裂隙的扩展和贯通规律。试验结果表明:无裂隙内水压时,在单轴压缩条件下倾斜裂隙在扩展贯通水平裂隙后裂纹的扩展路径和方向发生明显改变,试样最终发生劈裂破坏。侧压的增大抑制了倾斜裂隙端部翼裂纹和次生裂纹的萌生,高侧压下翼裂纹没有贯穿水平裂隙,试样破坏模式变成了剪切破坏。水力耦合作用下,单轴压缩时倾斜裂隙翼裂纹尖端的最大主应力分布范围随着内水压的增大逐渐变小,翼裂纹的起裂应力、起裂角和峰值强度逐渐降低,试样发生劈裂破坏。通过数值模拟得到的裂纹扩展贯通规律与试验结果具有良好的一致性,开展了不同内水压时倾斜裂隙扩展贯通无水压的水平裂隙的数值分析,随着内水压的增加倾斜裂隙首先萌生共面裂纹随后产生翼裂纹,翼裂纹扩展贯通水平裂隙时扩展路径同样会发生改变。水力耦合作用下侧压也会抑制翼裂纹的萌生,随着内水压的增大减弱了侧压对倾斜裂隙翼裂纹的抑制作用。Using the newly developed cement mortar materials, horizontal natural fissures and inclined precast flaws were arranged in the testing specimens, and different tests were carried out under uniaxial and biaxial compression conditions. Crack propagation and penetration process under different loading conditions were analyzed in detail. The test results show that: the propagation path and direction of pre-cracks change significantly after the pre-cracks meet the natural fissures during the coalescence process, and the phenomenon of ‘displacement jump’ appears. The increase of lateral confining stress inhibits the initiation of wing cracks and secondary cracks on the inclined crack tips. Under high lateral confining stress, these cracks do not penetrate through natural fissures, and the failure mode changes from splitting to shear failure. Under the action of hydraulic coupling, the maximum principal stress distribution of the wing crack tip in uniaxial compression gradually decreases with increase of internal water pressure, and the initiation stress, initiation angle and peak strength are also gradually reduced. The crack propagation and penetration law obtained by numerical simulation is in good agreement with test results. The numerical analysis of inclined flaws with different internal water pressures extending through the waterless pressure horizontal fissures is carried out. With the increase of the water pressure, the inclined flaws firstly initiate the coplanar cracks and then generates the wing crack. When the wing crack propagates through the horizontal fissures, the expansion path also changes. Under the action of hydraulic coupling, the lateral pressure also suppresses the initiation of the wing crack. The increase of water pressure weakens the inhibition of lateral pressure on wing cracks.

关 键 词：倾斜裂隙和水平裂隙 裂隙扩展试验 内水压 数值模拟 

分 类 号：TU452[建筑科学—岩土工程]