覆岩隔离注浆充填压实区形成机制研究

发布时间：2018-01-28 12:05

本文关键词： 建筑物下采煤部分充填覆岩隔离注浆充填注浆充填压实区关键层绿色开采　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：覆岩隔离注浆充填是一种有效的建(构)筑物压煤开采方法,其原理是通过高压注浆充填覆岩离层区,来压缩采空区破碎岩体并形成压实区,压实区与工作面之间的隔离煤柱联合控制覆岩关键层变形与破断,从而减小地表沉陷。因此在采空区内形成压实区是该技术成功的关键。但是已有研究并未深入探讨压实区形成的机制,具体包括注浆充填压力作用下压实区形成的力学机理、压实区形成的动态过程、压实区形成的影响因素。对此,本文综合采用力学分析、工程实测、物理模拟和数值模拟的方法开展了覆岩隔离注浆充填压实区形成机制的研究工作,主要研究成果与结论如下。建立了覆岩隔离注浆充填压实区形成的力学模型,并通过工程实测和物理模拟对模型的可靠性进行了验证。基于该模型给出了注浆充填压力向下传递到采空区的附加应力计算公式,通过注浆充填附加应力进一步导出了采空区应力与压缩量、压实程度和压实区宽度的计算公式。从而从理论上证明了覆岩隔离注浆充填可以在采空区内形成压实区。基于注浆充填压力变化的4阶段特征揭示了压实区形成的动态过程,为不同推进距下的注采比匹配设计奠定了基础。将注浆充填压力分为零压/降压、增压、稳压与超压阶段,并明确了各阶段内采空区的压实过程及其与工作面推进、注采比的关系。注浆压力进入增压阶段开始对采空区产生压缩作用,进入稳压阶段采空区的压实程度与压实区宽度随工作面的推进不断增加,稳压阶段是采空区压缩与压实区形成的关键阶段,进入超压阶段采空区的压实程度与压实区宽度进一步增加。揭示了主要地质采矿与注浆充填因素对压实区形成的影响规律,为优化注浆充填设计奠定了基础。注浆压力与工作面宽度的增加有利于压实区的形成;而采高、隔离层强度与厚度(注浆层位)的增加不利于压实区的形成;埋深、垮采比、垮落带岩体强度对压实区形成的影响较小。基于面宽对压实区形成的影响规律,给出了有利于压实区形成的最小工作面宽度确定方法。研究成果指导了淮北袁店二井煤矿7223工作面覆岩隔离注浆充填不迁村采煤试验。利用建立的压实区力学模型预计了采空区的压实情况,结果表明工作面具备形成压实区的条件,进而依据压实区形成的动态过程给出了不同推进距下的注采比匹配方案,按照该方案实施注浆充填后成功实现了不迁村采煤。
[Abstract]:Separated grouting filling of overburden is an effective method of building (building) coal compaction. Its principle is to compress the broken rock mass in goaf and form compaction area by high pressure grouting filling the separated zone of overburden rock. The separated coal pillar between compaction area and working face controls the deformation and fracture of the key strata of overburden rock. Therefore, forming compaction area in goaf is the key to the success of the technology. However, the mechanism of forming compaction zone has not been deeply studied. It includes the mechanics mechanism of compaction area formed under grouting filling pressure, the dynamic process of compaction area formation, and the influencing factors of compaction area formation. Physical simulation and numerical simulation have been carried out to study the formation mechanism of overburden isolated grouting filling compaction area. The main research results and conclusions are as follows. The mechanical model of overburden isolated grouting filling compaction area is established. The reliability of the model is verified by engineering measurement and physical simulation. Based on the model, the formula for calculating the additional stress that the grouting filling pressure is transferred down to the goaf is given. The stress and compression of goaf are further derived by grouting and filling additional stress. The compaction degree and the width of compaction zone are calculated. Thus, it is theoretically proved that the compaction zone can be formed in goaf by separated grouting filling of overburden. Based on the four-stage characteristics of grouting filling pressure, the formation of compaction zone is revealed. The dynamic process of. It lays a foundation for the matching design of injection-production ratio under different propulsive distance. The grouting filling pressure is divided into zero pressure / depressurization stage, supercharging stage, steady pressure stage and overpressure stage. The compaction process of goaf in each stage and the relation between the compaction process of goaf and the advance of face and the ratio of injection to production are clarified. The grouting pressure entering the stage of supercharging begins to produce the compression effect on the goaf. The compaction degree and the compaction area width of goaf are increasing with the advance of the working face, and the steady pressure stage is the key stage of the formation of the goaf compression and compaction zone. The degree of compaction and the width of the compacted area are further increased in the stage of overpressure, which reveals the influence of the main geological mining and grouting filling factors on the formation of the compaction area. It lays a foundation for optimizing grouting filling design. The increase of grouting pressure and face width is beneficial to the formation of compaction area. However, the increase of the intensity and thickness of the isolation layer (grouting layer) is not conducive to the formation of the compaction zone. The influence of buried depth, caving ratio and rock strength of caving zone on the formation of compaction zone is relatively small, based on the law of the influence of surface width on the formation of compaction zone. The method of determining the minimum face width in favor of forming compaction area is given. The research results guide the mining test of coal mining in 7223 coal face of No. 7223 coal face of Yuandian No. 2 Coal Mine, Huaibei. The compaction area is established by using the established compaction area. The mechanical model predicts the compaction of goaf. The results show that the working face has the condition of forming compaction area, and then according to the dynamic process of forming compaction area, the matching scheme of injection-production ratio under different propulsive distance is given. According to this scheme, the coal mining is realized successfully after grouting filling.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD823.7

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