富含软泥的溶洞性顶板巷道围岩稳定性控制研究

发布时间：2019-04-24 21:02

【摘要】：受煤层赋存条件的影响，富含软泥入侵的溶洞性顶板广泛分布于我国许多矿区，用于其孔洞发育、原位强度低、围岩整体性差，使得该类顶板巷道的稳定性控制已成为亟待解决的技术难题。本文以永聚煤业10#煤溶洞性顶板巷道为工程背景，结合溶洞注浆加固理论，分析研究溶洞性顶板巷道围岩的稳定性控制机理。采用溶洞注浆相似模拟、注浆岩体力学实验及数值模拟相结合的方法，探讨溶洞性顶板合理的注浆材料、注浆参数以及巷道支护方式，经实际工程应用与现场监测取得了良好的应用效果。主要研究结论如下：（1）富含软泥的溶洞性顶板，受孔洞效应影响其原位力学性能强度偏低（单轴抗压强度约为10.7MPa～18.9MPa）、自稳能力较差，在高地应力的作用下巷道顶板极易发生坍塌、冒落，溶洞性顶板巷道围岩的稳定性维护极为困难。（2）针对软泥入侵溶洞性顶板特性，结合相关围岩注浆加固原位改性理论，提出了对溶洞性顶板的分段封堵、分区注浆的加固技术，，注浆加固后其顶板围岩完整性得到明显改善，顶板支护结构的承载能力得到提高；分析表明注浆材料、注浆参数及支护方式的合理选择直接决定溶洞性顶板巷道围岩的稳定控制。（3）针对软泥入侵溶洞性顶板实际工程条件，运用注浆相似模拟、数值模拟以及力学性能实验等方法进行综合分析，确定溶洞性顶板注浆最优浆液水灰比为0.8：1；水玻璃用量为25%所用水泥体积量；巷道顶板最佳支护方式为拱形断面＋锚杆（索）＋29U型钢＋钢纤维混凝土联合支护。（4）试验表明：富含软泥的溶洞性顶板采用注浆加固后（水灰比0.8：1），围岩强度提高37.9%～165%，巷道围岩顶底板移近量减小58.61%～89.25%，巷道围岩两帮收敛量减小66.16%～93.79%。其顶板力学性能得到大幅提高，顶板围岩自稳能力有了较大的改善，注浆效果显著；数值模拟研究表明，高应力作用下软泥溶洞性顶板巷道破坏影响范围为巷道尺寸的3～4倍范围，该范围内溶洞的分布对巷道围岩的稳定性影响明显。（5）软泥-浆液结石体在较短时间内能完成膨胀变形（约8h），采用0.8：1的注浆水灰比，其最终膨胀量约为原结石体体积的3.1%，根据注浆工程手册，压力夯实注浆在该膨胀量作用下，效果最为显著；而且使得在溶洞性顶板巷道围岩注浆加固过程中，缩短了注浆施工过程，对软泥溶洞顶板快速加固效果明显，对富含软泥的溶洞性顶板注浆改性施工具有实际指导意义。（6）在永聚煤业10#煤轨道大巷进行了实际工程应用，并对实施的巷道围岩变形与锚杆（索）工作载荷进行了监测。结果表明：巷道围岩变形收缩量与顶板载荷最终均达到了稳定状态，溶洞性顶板巷道注浆加固与支护取得了良好的效果。
[Abstract]:Influenced by the existing conditions of coal seam, the karst roof rich in soft mud intrusion is widely distributed in many mining areas in China, which is used for the development of holes, low in-situ strength and poor integrity of surrounding rock. The stability control of this kind of roof roadway has become a technical problem to be solved urgently. In this paper, the stability control mechanism of surrounding rock of karst roof roadway is analyzed and studied based on the engineering background of No. 10 coal karst roof roadway in Yonggu coal industry and the theory of grouting reinforcement of karst cave. This paper discusses the reasonable grouting material, grouting parameters and roadway supporting mode by means of similar simulation of grouting in karst cave, mechanical experiment of grouting rock mass and numerical simulation. Through practical engineering application and on-the-spot monitoring, good application results have been obtained. The main conclusions are as follows: (1) the in-situ mechanical strength of the soft mud-rich roof is relatively low (uniaxial compressive strength is about 10.7MPa~18.9MPa) and its self-stabilization ability is poor due to the influence of void effect on the in-situ mechanical properties of the roof. Under the action of high in-situ stress, the roof of roadway is easy to collapse and fall, and it is very difficult to maintain the stability of surrounding rock of roadway with cave roof. (2) in view of the characteristics of soft mud intrusive karst roof, combined with the theory of in-situ modification of surrounding rock grouting strengthening, this paper puts forward the reinforcement technology of subsection sealing and sub-zone grouting for karst cave roof. After grouting reinforcement, the integrity of the surrounding rock of the roof is improved obviously, and the bearing capacity of the roof supporting structure is improved. The analysis shows that the reasonable selection of grouting material, grouting parameters and supporting mode directly determines the stability control of surrounding rock of karst roof roadway. (3) in view of the actual engineering conditions of the soft mud intrusion into the cave roof, the grouting similarity simulation, numerical simulation and mechanical performance experiment are used to carry on the comprehensive analysis, and the optimal grouting water-cement ratio of the solution-cavity roof grouting is determined to be 0.8 渭 1; The best supporting method for roadway roof is arch section + bolt (cable) + 29U steel + steel fiber reinforced concrete (SFRC). (4) the test results show that the strength of surrounding rock is increased by 37.9% and the moving amount of roof and floor of roadway is decreased by 58.61% and 89.25%, respectively, after grouting is used to reinforce the soft mud-rich cave roof (water-cement ratio 0.8%), and the strength of surrounding rock is increased by 37.9% and 16.5%, respectively. The convergence of the surrounding rock is reduced by 66.16% and 93.79%. The mechanical properties of the roof have been greatly improved, the self-stabilization ability of the surrounding rock of the roof has been greatly improved, and the grouting effect has been remarkable. The numerical simulation study shows that the influence range of tunnel failure of soft mud cave roof under high stress is 3 ~ 4 times that of roadway size, and the distribution of karst cave has obvious influence on the stability of surrounding rock of roadway under the action of high stress. (5) the soft mud-slurry aggregate can complete the expansion deformation in a short time (about 8 hours). The final expansion amount is about 3.1% of the original rock volume by using the grouting water-cement ratio of 0.8%. According to the grouting engineering manual, the final expansion of the soft mud-slurry aggregate can be completed in a short period of time (about 8 hours). The effect of pressure tamping grouting is the most obvious under the effect of the expansion amount. In addition, it shortens the grouting construction process in the process of grouting reinforcement of surrounding rock of karst roof roadway, which has obvious effect on the rapid reinforcement of soft mud karst cave roof, and has practical guiding significance for the grouting modification construction of soft mud rich karst roof. (6) the practical engineering application has been carried out in 10# coal track roadway of Yongju Coal Industry, and the deformation of surrounding rock and the working load of bolt (cable) have been monitored. The results show that the deformation and shrinkage of the surrounding rock and the load of the roof reach the stable state at last, and the grouting reinforcement and support of the roadway with the cave roof have achieved good results.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

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