为研究含孔洞-裂隙缺陷岩石损伤的宏细观特征,利用颗粒流程序PFC2D,对不同裂隙倾角、裂隙开度的红砂岩试样进行了单轴压缩数值试验,分析了不同类型缺陷试样的峰值强度、弹性模量、声发射特征、裂纹扩展特征随裂隙倾角及裂隙开度的变化情况。试验结果表明:砂岩的峰值强度和弹性模量与裂隙倾角间具有正相关关系,而裂隙开度的增加对试样峰值强度和弹性模量影响较小;随着裂隙倾角的增大,声发射累计振铃计数呈现前期缓慢减少、后期迅速增大的变化趋势;随着裂隙开度的增大,声发射累计振铃计数呈现先减小后增加再减小的变化趋势;随着裂隙倾角的增加剪切裂纹数量逐渐增加至与拉伸裂纹相近,破裂模式也由拉伸破坏变为拉剪混合破坏;不同开度砂岩破裂模式均为拉伸破坏;当裂隙倾角水平或垂直时,仅有一条裂隙参与主裂纹的形成;当裂隙倾角非水平或非垂直时,两裂隙之间产生崩落区,且均参与主裂纹的形成;随着裂隙开度的增大砂岩试样的破碎程度逐渐增大,除裂隙开度为1mm时因开度太小导致裂隙闭合未形成崩落区外,其余试样均产生崩落区,且崩落区范围逐渐增大,4种开度砂岩裂隙均参与主裂纹的形成。

To study the macro- and micro-structure characteristics of rock damage with pore-double fractures, a uniaxial compression numerical test was conducted on sandstone with different fracture inclination angles and crack openings by using PFC2D. The changes of peak strength, elastic modulus, acoustic emission characteristics, and crack propagation characteristics of rock samples with different types of defects, as the inclination angle and crack opening vary, were analyzed and the results were as follows: There is a positive correlation between the sandstone’s peak strength, elastic modulus and inclination angles while the increase of fracture openings has little effect on the peak strength and elastic modulus of sandstone samples. With the increase of fracture inclination angles, the cumulative ringing count of acoustic emission show a trend of slow decrease in the early stage and rapid increase in the later stage. The cumulative ringing count of acoustic emission show a trend of decreasing first, then increasing, and finally decreasing with the increase of fracture opening. With the increase of the fracture inclination angles, the number of shear cracks gradually increases to be similar to that of tensile cracks, and the failure mode changes from 黄冬梅等:含孔洞-双裂隙红砂岩宏细观损伤特征数值试验研究tensile failure to mixed failure. The fracture mode of sandstone with different opening are tensile failure. When the fracture inclination angles are horizontal or vertical, only one fracture is involved in the formation of the main crack. When the fracture inclination angles are not horizontal or vertical, there is a caving zone between the two fractures and both of them are involved in the formation of the main crack. With the increase of the fracture openings, the fracture degree of sandstone samples increases gradually. Except for samples with the fracture opening degree of 1mm, which failed to form caving zones as a result of the crack closure due to the small fracture opening, all the other samples have caving zones, whose range increases gradually. All the four kinds of sandstone cracks are involved in the formation of the main crack.