一种脆性底板断层裂隙破坏的分析方法

在对承压水上采煤煤层底板应力场的分析当中，目前大多数用的是弹性理论或者是弹塑性理论．根据断裂力学关于Ｇｒｉｆｆｉｔｈ二型裂纹断裂的理论，对此类问题中脆性底板中存在（未穿透底板的）断层情况给出一种新的分析方法．其结果可为试图解决此类问题的有限元程序编制者或现场工程技术人员直接采用．

含预制裂隙类岩石裂隙演化与破裂特征的试验研究

裂隙岩体是自然界中普遍存在的工程岩体,在外力作用下易引起岩体结构破坏失稳而诱发工程故事。为此,基于相似理论制作了含十字交叉裂隙的类岩石试样,利用RMT-150B岩石力学试验机,对含有不同裂隙长度和裂隙倾角的类岩石试样进行单轴压缩试验,分析其裂隙演化规律和破裂特征。研究结果表明:含预制裂隙试样的抗压强度明显低于完整试块;当主裂隙长度一定时,裂隙岩样的峰值应力随次裂隙长度的增大而降低;当裂隙倾角为0°和60°时,裂隙岩样表现为拉伸型翼形裂纹的破坏形式;当裂隙倾角为30°和45°时,裂隙岩样表现为拉剪混合型裂纹的破坏形式,既有翼形裂纹,又有次生共面裂纹。

Effect of fractures on mechanical behavior of sand powder 3D printing rock analogue under triaxial compression

In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.

酸化作用下页岩超声波透射试验研究

为了探索碳酸(H_(2)CO_(3))对页岩酸化作用引起的声学特性变化特征,以修武盆地海相页岩为研究对象,通过超声波透射试验方法研究了页岩试样被H_(2)CO_(3)处置后的时域信号、频域信号、波速、衰减系数等特征。结果表明:页岩试样被H_(2)CO_(3)处置后,超声波纵波和横波在页岩中的传播时间延长,纵波与横波幅值均呈现明显的下降特征;超声波频域内最大振幅下降,主频向低频方向发生偏移,部分页岩试样主频发生畸变;超声波纵波与横波波速均下降,纵波与横波衰减系数均增大。页岩试样被H_(2)CO_(3)处置后呈现的声波特性变化特征,反映出H_(2)CO_(3)酸化作用导致页岩孔隙度增大或者产生了破坏裂隙。

Dynamic behavior of rock during its post failure stage in SHPB tests

In order to investigate the micro-process and inner mechanism of rock failure under impact loading, the laboratory tests were carried out on an improved split Hopkinson pressure bar （SHPB） system with synchronized measurement devices including a high-speed camera and a dynamic strain meter. The experimental results show that the specimens were in the state of good stress equilibrium during the post failure stage even when visible cracks were forming in the specimens. Rock specimens broke into strips but still could bear the external stress and keep force balance. Meanwhile, numerical tests with particle flow code （PFC） revealed that the failure process of rocks can be described by the evolution of micro-fractures. Shear cracks emerged firstly and stopped developing when the external stress was not high enough. Tensile cracks, however, emerged when the rock specimen reached its peak strength and played an important role in controlling the ultimate failure during the post failure stage.

煤矿地表移动与岩石层滑移观测研究

为了研究煤矿地表移动与岩石层滑动之间的关系,以北部某煤矿为原型,分别在该煤矿工作面附近建立了地表移动观察站。通过对实测资料的分析与研究,得到了南屯煤矿该区域综采条件下的地表移动变形规律与起动步距参数,结合数值模拟,对概况地表移动与岩石层滑移情况进行深入分析。

Overburden failure and the prevention of water and sand inrush during coal mining under thin bedrock

Coal mining under thin bedrock or thick unconsolidated soil layers brings mining problems related to these special geological conditions. The meaning of the term ''thin bedrock'' is defined through the thick- ness statistics of the coal seam and the bedrock layer. The coal-bearing strata having thick, unconsoli- dated aquifers and thin bedrock located at the Taiping Coal Mine in Shandong province were taken as a geological prototype for subsequent study. The geological, hydro-geological and engineering character- istics of the thin bedrock were analyzed. An engineering geological model was than established. Overbur- den failure and the development of ''Three Zones'' were studied by physical model tests. The rupture pattern and rock failure were analyzed for mining conditions under thin bedrock. The height of the caving zone and the freely flowing water fractured zone of different mining thicknesses were separately calcu- lated. The results show that a mining thickness greater than 3.5 m causes the height of the freely flowing water fractured zone to be sufficient to touch the weathered zone and the bottom of the Quaternary sys- tem aquifer, to various degrees. This, then, would lead to water and sand inrush into the working face. Measures to prevent water and sand flow inrush disasters by eliminating the power source are put fore- word. A field dewatering scheme was designed and observational data were obtained. The dewatering project had an obvious effect and the water level at working face number 8309 dropped to a safe level. The average draw down of the groundwater was observed to be 7.86 m. This showed that the dewatering project played a role in decreasing the hydraulic pressure and ensuring safety mining.

工作面顶板安全状况钻孔窥测分析

文章采用钻孔窥测的方法分析某工作面顶板状况。首先,根据实验和研究目的选择了合理的实验设备YTJ20钻孔窥视仪。根据现场施工和设备观测的需要,设计观测测点布置方案,并规范整个观测流程。通过对工作面胶带巷道相隔30 m的临近面轨顺顶板岩层的深部钻孔窥视,并对钻孔展开图进行分析,得出某工作面顶板较坚硬,但是竖向裂隙较发育,围岩垂直应力明显大于水平应力。顶板在3 m范围内的破碎状态严重,在3 m后顶板的破碎状况逐渐减小。

采动覆岩涌水溃砂灾害模拟试验系统研制与应用

为研究煤层开采过程中覆岩涌水溃砂灾害的演化特征,研制采动覆岩涌水溃砂灾害模拟试验系统。该系统由主体承载支架、试验舱、承压水仓、模拟采煤装置、储能罐、水压水量双控伺服系统和位移应力双控伺服系统组成,具有模拟空间大、可视度优、密封性好、加载方式多样、数据精度高等特点。以西部地区煤炭赋存地层为工程背景,利用研制的低强度非亲水相似材料对煤系地层进行模拟铺设,并对其进行模拟开采,较好地再现了覆岩涌水溃砂灾害孕育、发展及发生的全过程,获得工作面开采过程中覆岩变形破坏、裂隙发育扩展、水砂通道形成及水砂突涌参数和特征。试验结果表明该试验系统稳定可靠,研究方法及结果对进一步认识采煤工作面涌水溃砂灾害的形成机制具有指导和借鉴意义。