煤层开采区地表拉张裂隙的形成与演化模拟试验研究

发布时间：2018-05-14 21:50

本文选题：地下开采 + 地表变形　；参考：《安徽理工大学》2017年硕士论文

【摘要】：煤炭作为我国的主要化石能源,其在我国国民经济建设中所占据的地位是不可替代的。我国经济的发展离不开煤炭资源的开发与利用。然而随着煤炭的采出,矿区地表常常发生塌陷变形,而地表塌陷形成过程中往往伴有裂隙的形成。地表裂隙的形成改变了土壤原有的内部结构,加速了水土的流失,降低了土壤中营养元素的含量,促使耕地贫瘠化。根据裂隙的形成机理将裂隙分为四类,即挤压型裂隙、滑动型裂隙、塌陷型裂隙、拉张型裂隙。本文主要是对煤层开采区地表拉张型裂隙的形成与演化进行研究。拉伸型裂隙是由于地表受到的拉应力超过了其所能承受的最大抗拉强度时形成的,裂隙一般呈现上宽下窄的形态,裂隙发育深度相对较浅。拉伸型裂隙的形成加速了地表土壤的水土流失,改变了地表形态及耕地的内部构造,降低了土壤质量。研究地表拉张裂隙的形成与演化不仅可以对裂隙的形成与发育规律有更清楚的认识,还可以对裂隙的形成位置进行预测。本文通过模拟煤层的开采,对煤层开采过程中地表拉张型裂隙的形成与演化进行了研究,并对不同开采厚度下裂隙的形成与发育情况进行了对比分析。试验过程对裂隙的特征值进行了测量,应用并行电法对模型内部裂隙的发育情况进行了监测,对观测面上裂隙的发育过程做了拍照记录,后期通过对并行电法得到的反演剖面图进行分析、数字图像的处理,结合观测数据的分析处理结果,得到了以下研究成果:(1)煤层开采过程中拉张裂隙超前于开采工作面一定距离形成,随着煤层开采的进行裂隙宽度先变大后减小。(2)采深相同时,开采厚度越大裂隙发育达到最大值时的宽度、深度也越大;煤层采长相同时,煤层开采厚度小时地表形成裂隙的密度大。(3)并行电法对试验模型内部拉张裂隙的形成与演化过程进行了很好的表征。根据模型土体内部电阻率阻值大小在开采过程中的变化,通过对多阶段电阻率反演剖面图的分析,对试验过程中裂隙的形成位置,宽度、深度的发育大小进行了直观的表现,为研究裂隙的形成与演化提供了理论支撑。
[Abstract]:As the main fossil energy in China, coal plays an irreplaceable role in the national economy construction. The development of our country's economy is inseparable from the development and utilization of coal resources. However, with the coal mining, the surface of the mining area often collapse deformation, and the formation process of surface collapse is often accompanied by the formation of cracks. The formation of surface cracks changes the original internal structure of soil, accelerates soil erosion, reduces the content of nutrient elements in soil, and makes cultivated land barren. According to the formation mechanism of fractures, the fractures can be divided into four types, namely, compression-type fissures, sliding fissures, collapse-type fissures and tensioning fissures. In this paper, the formation and evolution of extensional fractures in coal seam mining area are studied. The tensile fracture is formed when the tensile stress on the surface exceeds the maximum tensile strength it can bear. The fracture is generally in the form of upper width and narrowness and the fracture development depth is relatively shallow. The formation of extensional fissures accelerates soil erosion, changes the surface morphology and the internal structure of cultivated land, and reduces the soil quality. The study of the formation and evolution of the surface tensile fractures can not only have a clearer understanding of the formation and development law of the fractures, but also predict the formation position of the fractures. In this paper, the formation and evolution of tensile fractures in coal seam mining are studied by simulating the mining of coal seams, and the formation and development of fractures under different mining thickness are compared and analyzed. The characteristic values of fractures were measured during the experiment, the development of cracks in the model was monitored by parallel electric method, and the development process of cracks on the observation surface was recorded by taking pictures. In the later stage, the inversion profile obtained by the parallel electric method is analyzed, the digital image is processed, and the analysis and processing results of the observation data are combined. The following research results are obtained: in the process of coal seam mining, the tensile fissure is formed in advance of a certain distance from the mining face, and with the coal seam mining the crack width increases first and then decreases. 2) when the mining depth is the same, The greater the mining thickness, the greater the width and depth of the fissure when it reaches the maximum, and the more the coal seam looks at the same time, The formation and evolution of tensile fractures in the test model are well characterized by parallel electrical method. According to the variation of the internal resistivity resistance of the model soil in the mining process, through the analysis of the multi-stage resistivity inversion profile, the formation position, width and depth of the cracks in the test process are shown directly. It provides theoretical support for studying the formation and evolution of fractures.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD327

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