摘要
对含平行裂隙相似材料试件进行单轴压缩试验,并用PFC3D模型进行了模拟。通过试验和DEM结果对比分析,探讨了含平行双裂隙岩体在单轴压缩下的破坏规律。研究结果表明:在变形破坏阶段,当轴向应变达到0.02后,应力-应变曲线出现"双峰"现象;抗压强度随预制裂隙倾角的增大呈非线性变化。预制裂隙倾角较小时(≤45°),抗压强度随裂隙倾角变化规律不明显。预制裂隙倾角在45°时,试块抗压强度最低。预制裂隙倾角较大时(≥45°),抗压强度随裂隙倾角的增大而增大;裂纹起裂区域均位于两预制裂隙中间区域。随着预制裂隙倾角的增大,萌生裂纹的端点位置从两端点均在预制裂隙中间,向一端点位于裂隙中间另一端点位于预制裂隙顶端,到两端点均位于预制裂隙顶端转变;试件不同预制裂隙倾角对应不同的岩桥倾角,岩桥倾角较大时(≥60°),岩桥倾角与抗压强度呈正相关关系。
The uniaxial compression test was carried out on the materials specimens with similar parallelcracks and it was simulated using the PFC3D model.A failure mechanism study of jointed rock with parallel-cracks was discussed by comparison of uniaxial compression test and DEM.The results showed that:at the deformation and failure stage,the"double peak"phenomenon appears in the stress-strain curve when the axial strain reaches 0.02.The uniaxial compressive stress varies nonlinearly with the increase of the pre-existing cracks dip angle.When the pre-existing cracks dip angle is no more than 45°,the uniaxial compressive stress does not change significantly with the pre-existing cracks dip angle.The uniaxial compressive stress of specimen with 45°pre-existing cracks dip angle is lowest.The uniaxial compressive of specimen increases with an increasing pre-existing cracks dip angle when the pre-existing cracks dip angle is larger than 45°.The range of crack initiation is located in the middle of the two pre-existing cracks.With the pre-existing cracks dip angle increase,the crack initiation position extends from the end of the crack at the middle of the pre-existing cracks to the end point is located at the other end of the crack at the tip of the pre-existing cracks,and finally transform to both ends are the crack tip.Different pre-existing cracks dip angle of the specimens corresponds to different ligament angles.When the ligament angle is large than 60°,it is positively correlated to the uniaxial compressive stress.
作者
李玉成
孙浩程
房媛
杨定韬
孟祥瑞
LI Yucheng;SUN Haocheng;FANG Yuan;YANG Dingtao;MENG Xiangrui(University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《水资源与水工程学报》
CSCD
2019年第5期215-220,共6页
Journal of Water Resources and Water Engineering
基金
国家自然科学基金项目(10872133)
上海市软科学研究领域重点项目(18692106100)
