1. Mine Construction Branch,China Coal Research Institute,Beijing　 100013,China; 2. School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing　 100083,China; 3. Beijing China Coal Mine Engineering Co. ,Ltd. ,Beijing　 100013,China

剪切破坏断面是弱胶结砂岩在破坏过程中断裂后所形成相匹配的表面,断面形貌特征根据受力方式和饱水条件的不同形成差异显著。利用3D激光扫描对剪切破坏断面进行精确测量,结合地理信息系统(GIS)技术对不同受力方式和饱水条件下的破坏断面形貌进行三维可视化处理和定量分析,并采用扫描电镜从细观角度对产生的断面形貌特征差异及其破坏机理进行研究。试验结果表明:随夹具角度的增加,破裂面法向力降低,法向力的减小是导致破裂面扰动较大以及剪切断裂面粗糙度和起伏度增加的主要原因之一;通过饱水岩样细观结构的分析发现,弱胶结砂岩骨架颗粒自身吸水膨胀软化,骨架颗粒之间的黏连性变差,胶结程度降低,直接导致试件抗剪强度降低,同时,水对剪切破坏面扰动影响也降低,致使在相同受力条件下饱水试件断裂面粗糙度和起伏度相对较小;胶结物质的遇水软化的特性是决定弱胶结砂岩剪切破坏断面形貌的关键因素,为进一步研究弱胶结砂岩损伤演化过程及破坏机理提供可靠的试验依据。

The shear failure surface is formed by the fracture of weakly cemented sandstone during the damage process. The features of such surface are vastly different depending on different forces and water saturation conditions. During this study,the researcher uses 3D laser scanning to accurately measure the shear fracture surface,leverages the Geographic Information System (GIS) technology to conduct the three-dimensional visualization and quantitative anal- ysis of the surface caused by different forces and water saturation conditions,and utilizes the scanning electron micros- copy (SEM) to explore the morphology of the surface as well as its failure mechanism in a micro-level. The results show that with the increase of the angle of the fixture,the normal forces of the fracture surface decrease,which leads to the disturbances of the fracture surface and the increase of the roughness and fluctuation degree of the shear fracture surface. With the interactions of water and the sandstone,the grains of the weakly cemented sandstone skeleton swell and soften with water,and the adhesion of the skeleton particles dete-riorate,while the cementation decreases. This di- rectly leads to the decrease of the anti-shear capability of the specimen. At the same time,the impact of disturbances on the shear failure surface is reduced,thus the roughness and the fluctuation degree of the fracture surface with water saturation under the same force stress conditions are relatively small. The mechanical properties of the cemented mate- rial are the key to the morphology of the shear fracture surface of the weakly cemented sandstone,which provides an experimental foundation to further study on the damage evolution process and failure mechanism.

国家重点研发计划资助项目(2016YFC0600801)；国家自然科学基金重点资助项目(51534002)；

SONG Zhaoyang,JI Hongguang,LIU Zhiqiang,et al. Morphology and failure mechanism of the shear fracture surface of weakly cemented sandstone with water saturation[ J]. Journal of China Coal Society,2018,43(9):2444 -2451.