剪切破坏是煤矿开采中岩石破坏的主要类型之一。开采扰动引起顶板覆岩结构与完整性遭到破坏，致使含水层以层间径流向垂向径流转变，水-岩作用下岩石剪切破坏特征将发生显著改变。为研究水作用下岩石剪切破坏特征演化规律，以神东矿区乌兰木伦煤矿3-1煤顶板砂质泥岩为研究对象，通过薄片显微鉴定试验得到了其组分及微结构特征;结合无损浸水试验装置测试了其含水率随时间变化规律，确定了砂质泥岩含水率状态，为研究含水率影响下砂质泥岩直剪特性演化规律提供了可能;利用自制的岩石直剪试验系统，并结合声发射监测结果，探讨了含水率影响下砂质泥岩直剪变形破坏规律、强度损伤及声发射特征。结果表明:砂质泥岩具有水平层理构造，其中的粉砂质碎屑质量分数为40%，泥质质量分数为60%，黏土矿物主要为高岭石和伊蒙混层，占整体矿物成分的75%;根据岩样含水率随浸水时间变化规律，将其划分为快速增长(0~18 h)、缓慢增长(18~42 h)和稳定(42 h~)3个阶段;随着含水率增加，岩样抗剪强度、黏聚力和内摩擦角分别呈指数、负指数和线性降低;由干燥到饱和，黏聚力和内摩擦角分别下降77.9%和33.3%;随着含水率增加，岩样声发射累计计数逐渐减小，破坏后宏观主裂隙平整度降低;峰值破坏阶段低含水率岩样产生大尺度张拉裂隙，高含水率岩样产生小尺度张拉裂隙。

Shear failure is one of the main types of rock failure in coal mining.The structure and the integrity of roof strata will be destroyed by mining disturbance,which leads to the change of flow mode of water in aquifer from interlayer runoff to vertical runoff.The waterrock interaction in this process will change the shear failure characteristics of rocks significantly.In order to study the evolution law of shear failure characteristics of rocks under water effect,the sandy mudstone of 3-1 coal roof of Wulanmulun coal mine was taken as the study object.The composition and microstructure characteristics of sandy mudstone were obtained by the microscopic identification test of thin section.The variation of moisture content of sandy mudstone with time was tested by nondestructive immersion test equipment.The moisture content of sandy mudstone was determined,which provided a possibility for studying the evolution law of the direct shear characteristic of sandy mudstone under the effect of moisture content.The direct shear deformation and failure law,strength damage and acoustic emission characteristics of sandy mudstone under the influence of moisture content were discussed with the selfdeveloped rock direct shear test system and acoustic emission monitoring results.The result show that sandy mudstone has horizontal bedding structure,and the content of silty debris is 40% and the content of argillaceous is 60%.Clay minerals in sandy mudstone mainly include kaolinite and illite,accounting for 75% of total mineral constituent.According to the variation law of moisture content of rock specimens with immersion time,the moisture content immersion time curve can be divided into three stages:rapid growth (0-18 h),slow growth (18-42 h) and stable (42 h-).With the increase of moisture content,the shear strength,the cohesion and the internal friction angles of rock specimens decrease exponentially,negative exponentially and linearly,respectively.From dry to saturated,the cohesion and the internal friction angle of sandy mudstone decrease by 77.9% and 33.3% respectively.With the increase of moisture content,the cumulative count of acoustic emission of the rock specimen decreases.With the increase of moisture content,the flatness of macro main crack decreases after the rock specimen is destroyed.In the peak failure stage,the rock specimens with low moisture content produce largescale tension cracks,while the rock specimens with high moisture content produce smallscale tension cracks.The research findings provide a useful references to waterrock interaction problem in the engineering such as the waterenriched roadway of coal mine,water preserved mining and dam design of underground reservoir.

1 试样制备

2 试验装置及试验方案

3 含水率对砂质泥岩直剪力学特性的影响

   3.1 不同含水率岩样剪应力-剪应变曲线

   3.2 不同含水率岩样抗剪强度

   3.3 不同含水率岩样黏聚力和内摩擦角

   3.4 不同含水率岩样剪切破坏特征

4 含水率对砂质泥岩声发射特征的影响

   4.1 不同含水率岩样累计声发射特征

   4.2 不同含水率岩样裂隙发育类型

   4.3 不同含水率岩样的裂隙发育程度

5 讨论

6 结论