无煤柱自成巷开采试验与顶板结构变形演化机制研究

No-pillar mining technique with automatically formed gob-side entry retaining is a kind of original and innovative mining technology without coal pillar and tunnelling, which has better application prospect and higher research value. But at present, most of the research on this technology focuses on the field macroscopic laws, and there are few basic theories and experimental studies. This project intends to carry out the mining test of no-pillar mining technique with automatically formed gob-side entry retaining on the basis of the previous field law research. First, the basic parameters of 3D model test will be determined through the basic performance test of model material. Secondly, the mechanical properties of precast roof rock mass with element blocks will be tested, and the ratio parameters of element blocks and cementing materials will be determined, which provided a new method for simulating the fracturing and crack-expansion effect of caved rock mass. Then, based on the resistivity test of roof rock mass in the deformation process, the resistivity method characterization system of mechanical properties of rock mass will be constructed, and a monitoring method of rock mass failure process in 3D physical model test will be formed. Finally, a three-dimensional physical model test will be carried out in the whole process of no-pillar mining technique with automatically formed gob-side entry retaining. Based on the results of resistivity, displacement and stress monitoring, the fracture and failure characteristics, evolution rules of motion state and deformation expansion mechanism of roof structure without coal pillar under mining disturbance will be studied. The research results can provide the foundation design basis for the application of no-pillar mining technique with automatically formed gob-side entry retaining.

无煤柱自成巷开采技术是我国原始创新的一项无煤柱、无掘巷开采技术，具有较好的应用前景和较高的研究价值。但目前针对该技术的研究多集中在现场宏观规律层面，基础理论和试验研究不足。本项目拟在前期现场规律研究的基础上，开展无煤柱自成巷开采试验与顶板结构变形演化机制研究。首先，通过模型材料基础性能测试，确定三维模型试验基本参数。其次，开展单元块预制碎胀岩体力学性能试验，明确单元块和胶结材料配比参数，为模拟垮落岩体碎胀效应提供一种新方法。然后，基于顶板岩体试件变形过程中的电阻率试验，构建顶板岩块受载过程中力学性质的电阻率法表征体系，形成一种三维物理模型试验内部岩体破坏过程监测方法。最后，开展无煤柱自成巷开采全过程三维物理模型试验，基于电阻率、位移和应力监测结果，研究无煤柱自成巷顶板结构在开采扰动下的断裂破坏特征、运动位态演变规律以及变形扩展机制。研究成果可为无煤柱自成巷开采现场工程应用提供基础设计依据。

无煤柱自成巷开采是我国自主创新的一项无煤柱、无掘巷开采技术，具有较好的应用前景。但目前针对该技术的研究多集中在现场宏观规律层面，关于顶板结构变形规律及其控制设计方法的研究仍有不足。本项目在前期现场规律研究的基础上，综合采用理论分析、模型试验和数值模拟等方法，开展了无煤柱自成巷开采顶板结构变形演化机制方面的研究工作。主要进展包括：（1）明确了无煤柱自成巷开采顶板岩层结构特征，建立了顶板岩层“承压结构”和“卸压结构”力学模型，揭示了各结构变形规律及稳定机制。（2）构建了无煤柱自成巷开采全过程围岩应力状态演化模型，揭示了无煤柱自成巷开采围岩应力演化规律，明确了无煤柱自成巷开采条件下围岩的力学平衡机理。（3）建立了无煤柱自成巷开采顶板控制理论模型，明确了顶板结构在不同阶段的稳定特征和控制机理，提出了无煤柱自成巷开采围岩控制设计计算方法。项目基本按计划任务完成了相关研究工作，经费支出合理，达到了预期目标。项目执行期间，研究成果发表SCI/EI学术论文12篇，申请中国发明专利4项（2项已授权，2项实审），支撑获得省部级科技奖励1项。研究成果可为无煤柱自成巷开采现场工程支护设计提供科学依据，为我国自主创新的煤炭资源开采新工法推广应用奠定了理论基础。