软弱覆岩强含水层下综放开采覆岩运移规律及水砂防控技术研究

发布时间：2018-05-23 18:27

本文选题：含水层 + 综放开采　；参考：《中国矿业大学》2017年博士论文

【摘要】：敏东一矿首采盘区覆岩性质及含水层形态特殊,覆岩偏软,且含水层多、含水性强,针对性开展软弱覆岩强含水层下综放开采覆岩运移规律及水砂防控技术研究对于保障矿井安全生产、降低开采活动对地表生态环境的破坏极为重要。本文在对首采盘区覆岩含水层富水性评价、覆岩运移规律及含水层对工作面充水溃砂影响等内容研究的基础上,建立了适用于敏东一矿及类似条件下矿井工作面的水砂防控技术体系。论文主要研究工作及成果如下:(1)根据地质勘探数据,评价分析了矿井首采盘区开采充水水源及含水层富水性,综合利用地面电法和矿井直流电法对受开采影响的主要含水地层的富水情况进行探测,揭示了敏东一矿强含水层的赋存特征。物探所得结果与实际情况较吻合。(2)运用钻孔注水法实测得到了敏东一矿首采盘区覆岩“两带”高度,结果表明:垮落带高度为36.65 m,垮采比为4.76;导水裂缝带高度为83.78 m,裂采比为10.88。利用实验室力学性质测试和现场实测数据对离散元程序UDEC模拟参数进行校核,反演不同采高时覆岩运移特征及两带高度,所得垮采比最大和最小值分别为4.25和3.5,平均3.9;裂采比最大和最小值分别为11和8.1,平均9.3,与现场实测结果较为接近。综合钻孔实测和数值计算分析了敏东一矿软弱覆岩强含水层下综放开采覆岩破坏规律。(3)通过实验室相似模拟,得到了工作面覆岩导水裂隙发育规律,相似模拟所得直接顶初次垮落步距大于现场实测结果,而老顶周期来压步距与现场实测结果相近。由于相似模型中垮落带覆岩呈层状充填采空区,其所得垮落带和裂隙带高度均比现场实测结果偏大,通过铺设散体砂石、预制节理及增加直接顶强度等方法预处理模型垮落带内岩层,可有效提高相似模拟结果的可靠性。(4)针对敏东一矿地层岩性及强度特征,开展了0-0.5 mm和0.5-1 mm两种砂径骨料的相似模拟试验,得到了覆岩导水裂隙演化对模型骨料粒径变化的敏感程度,揭示了软弱覆岩综放开采裂隙及应力演化规律。结果表明,相似材料骨料砂径越小,其强度越大,随砂径增大,相似材料试件破坏由剪切主导型逐渐转变为张拉主导型;砂径越大,相似模拟中覆岩断裂步距越小,覆岩裂隙发育越充分,过小的砂径反而不利于覆岩导水裂隙演化。(5)构建了敏东一矿软弱覆岩强含水层及类似条件下综放开采防治水体系。首先防止含水层溃水、溃砂,其次避免工作面涌水量超限,最后补充顶板水疏降技术;提出了“顶水开采与疏干或疏降开采相结合、先疏后采与边采边疏相结合、钻孔疏干或疏降与回采疏干或疏降相结合、分段控制开采厚度”的防治水总方案,有效保证了矿井的安全综放开采。
[Abstract]:In Mindong No. 1 Mine, the overlying rock and aquifer form are special, the overburden is soft, the aquifer is abundant, and the water content is strong. It is very important to carry out the study of overburden migration law and water and sand prevention and control technology of fully mechanized caving mining under the strong aquifer of weak overburden rock in order to ensure the safety of mine production and reduce the damage to the surface ecological environment caused by mining activities. Based on the study of the water-rich evaluation of overburden aquifer in the first mining area, the law of overburden rock migration and the influence of the aquifer on the water filling and sand collapsing in the working face, etc. The technical system of water and sand prevention and control is established for Mindong No.1 Mine and similar mining face. The main research work and results are as follows: (1) based on the geological exploration data, this paper evaluates and analyzes the water-filled water source and the water-rich aquifer in the first mining area of the mine. The surface electric method and the mine direct current method are used to detect the water-rich condition of the main water-bearing strata affected by the mining, and the occurrence characteristics of the strong aquifer in Mindong No. 1 Mine are revealed. The geophysical exploration results are in good agreement with the actual situation. (2) the height of overlying rock in the first mining area of Mindong No. 1 Mine has been obtained by using borehole water injection method. The results show that the height of caving zone is 36.65 m, the ratio of collapse to production is 4.76, the height of water-conducting fracture zone is 83.78 m, and the ratio of fracture to production is 10.88. The parameters of discrete element program (UDEC) simulation are checked by laboratory mechanical property test and field measurement data, and the characteristics of overlying rock migration and the height of two zones are inversed when mining height is different. The maximum and minimum ratio of collapse and production are 4.25 and 3.5, respectively, with an average of 3.9, and the maximum and minimum of fracture-production ratio are 11 and 8.1, respectively, with an average of 9.3, which is close to the field measured results. The failure law of overburden rock in fully mechanized caving mining under strong aquifer of weak overburden in Mindong No. 1 Mine is analyzed by comprehensive borehole measurement and numerical calculation. The initial collapse step distance obtained by similar simulation is larger than that of field measurement, but the pressure step distance of main roof cycle is close to that of field measurement. Because the overburden of the caving zone in the similar model is layered filled with goaf, the height of the caving zone and the fissure zone is higher than that of the field measurement. The preprocessing methods such as precast joints and increasing direct top strength can effectively improve the reliability of the similar simulation results in the rock strata in the caving zone.) aiming at the lithology and strength characteristics of Mindong No. 1 mine, the prefabricated joints and other methods can effectively improve the reliability of the similar simulation results. The similarity simulation tests of 0-0.5 mm and 0.5-1 mm sand diameter aggregates are carried out. The sensitivity of the evolution of overburden water-conducting fractures to the change of model aggregate particle size is obtained, and the fracture and stress evolution law of fully mechanized caving mining in weak overburden is revealed. The results show that the smaller the aggregate diameter of similar material is, the greater its strength is, and with the increase of sand diameter, the failure of similar material specimen gradually changes from shear leading type to tension-oriented type, and the larger the sand diameter, the smaller the fracture step distance of overburden rock in similar simulation. The more fully developed overburden fissures, the smaller the sand diameter is, which is not conducive to the evolution of overburden water conductivity fissures.) the strong aquifer of weak overburden rocks in Mindong No. 1 Mine and the water prevention system of fully mechanized caving mining under similar conditions are constructed. First of all, to prevent aquifer from collapsing water and sand, secondly to avoid overflowing water from working face, and finally to supplement roof water thinning and falling technology, and to put forward the "combination of top water mining and draining or thinning mining, first and then mining and edge mining," By combining dryness or thinning of boreholes with dryness or thinning of mining, and controlling mining thickness by stages, the total scheme of water prevention and control can effectively ensure the safety of fully mechanized caving mining in coal mines.
【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】：TD745;TD325

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