基于地质概化的坚硬厚基岩覆岩裂隙场演变特征研究

    Study on evolution characteristics of fracture field in hard thick overlying strata based on geological generalization

    • 摘要: 精准掌握采动覆岩导水裂隙带演化特征是防止工作面突水灾害发生的重要基础,尤其对于西部矿井高强开采条件尤为重要。以榆树湾煤矿201西翼盘区为背景,以各砂岩层单轴抗压强度、RQD、砂岩层厚度作为系统聚类分析指标提出了厚基岩地质概化方法,系统研究了不同基岩层厚度对导水裂隙带发育高度、裂隙角度、频次、节理应变能演变规律的影响,确定了导水裂隙带高度与节理总应变能的量化关系。研究结果表明:基于地质概化方法模拟所得导水裂隙带发育高度随基岩厚度增大呈现对数正相关增大趋势,且增加速率逐渐减小,该规律通过与邻近矿井实测结果对比分析,验证了其准确性;随着基岩厚度的增大,导水裂隙带内垂直裂隙发育频次显著增大,水平裂隙反之,这表明基岩厚度的增大对导水裂隙带内水平裂纹的萌生与扩展具有一定抑制作用;导水裂隙带发育高度与覆岩能量释放程度密切相关,随节理最大应变能和总应变能的增加呈指数增加特点,且增加速率逐渐增大。

       

      Abstract: Accurately grasping the evolution characteristics of the water-conducting fracture zone in the mining overburden is an important basis for preventing the occurrence of water inrush disasters in the working face, especially for the high strength mining conditions in the western mines. Taking the 201 west wing area of Yushuwan Coal Mine as the background, taking the uniaxial compressive strength of each sandstone layer, RQD, and thickness of sandstone layer as the system cluster analysis indexes, this paper proposes a geological generalization method for thick bedrock, systematically studies the influence of different bedrock layer thickness on the development height, fracture angle, frequency, and joint strain energy evolution law of the water-conducting fracture zone, and determines the quantitative relationship between the height of the water-conducting fracture zone and the total joint strain energy. The research results show that: the development height of the hydraulic fracture zone simulated based on the geological generalization method presents a log-positive correlation increasing trend with the increase of the bedrock thickness, and the increasing rate gradually decreases. This law is verified by comparing with the measured results of the adjacent mines; with the increase of the thickness of bedrock, the development frequency of vertical cracks in the water-conducting fracture zone increases significantly, while the horizontal cracks in the water-conducting fracture zone increase, which indicates that the increase of the thickness of bedrock has a certain inhibition effect on the initiation and expansion of horizontal cracks in the water-conducting fracture zone; the development height of the water-conducting fracture zone is closely related to the energy release degree of the overlying rock. It increases exponentially with the increase of the maximum strain energy and the total strain energy of the joint, and the increasing rate gradually increases.

       

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