煤矿层滑构造的物理模拟及预测方法研究

Interlayer-gliding structures are well developed in coalmines. It has considerable adverse effects on seam thickness, quality, roof and floor, coal and gas outburst, mine water inrush et al. The coal seam is easy to become main detachment surface which is almost associated with small faults within 3 meters of fault throw. Intensive investigation of coalfield exploration is unable to accurately determine the locations. Exploration technique of seismic reflection wave could control the faults within 5 meters throw. 3-D seismic exploration of 3D could forecast small faults within 2 to 3 meters throw which accuracy rate is only about 30%. Coal Geology technicians and scientists continue to explore the effective means to forecast the coal interlayer-gliding. Scaled physical experiment is an important way to investigate the evolution and genetic mechanics of structural deformation. The project is planned to analyze mine geology and 3-D seismic data of Huainan Coalfield. We plan to analyze tectonic stress fields by conjugated shear joints, filled-in veins and small folds et al. Based on the principle of similarity, series of simulation experiments are carried out to in-depth study main controlling factors of interlayer-gliding structures. Combined with conclusions of quantitative evaluation of interlayer-gliding structures,comprehensive analysis of genetic mechanics are carried out. We establish models to forecast the locations of interlayer-gliding structures and influence on coal seam in unexplored mining area. The project will not only enrich and improve the mine geological structure theory, but also provide some new inspiration for the study of seam rheology. It also provides a theoretical basis for coal mines to design mining area.

煤矿层滑构造对于煤厚、煤质、煤与瓦斯突出、矿井突水等有很大不利影响,由于煤层易成为主滑面或滑移带，大多与断距小于3m以下的小断层伴生，煤田精查勘探无法对其准确判断，地震反射波勘探只能对落差5m以上断层控制较好，三维地震勘探对断距为2～3m的断层预测准确率只有30%左右。采取何种有效的手段对煤矿层滑构造进行预测，一直是煤田地质人员和科研工作者不断探索的问题。本项目拟在淮南煤田矿井地质和三维地震资料详细分析的基础上，对不同类型的层滑构造进行观察，利用小构造的变形特征，解析井田古构造应力场，根据研究区块地质原型的边界条件，以相似性原则作为约束条件，开展不同类型层滑构造的模拟实验，深入研究层滑构造的主控因素和力学机制，结合层滑构造定量评价指标，预测未开拓采区层滑构造及其对煤层的影响。本研究不仅丰富和完善了矿井地质理论，而且还可以给煤矿生产部署提供参考依据。

通过对淮南和淮北煤田顾桥矿、张集矿、孙疃矿等层滑构造进行调查和研究，确定了煤系地层中不同构造部位层滑构造的地质模型，即揉皱型和断裂型两大基本类型，根据不同层滑构造的组合形态又可分为书斜式、垒堑式、阶梯状、“ｙ”与反“ｙ”字形等。通过对淮北地区地表露头、井下小构造等调查，采用赤平投影方法解析了不同井田的古构造应力场，划分构造期次，即自石炭–二叠纪含煤地层沉积后，淮北煤田至少经历了3期较大的构造事件，分别为印支期近SN 方向的挤压、燕山早期NWW-SEE方向的挤压、燕山晚期NNE-SSW方向挤压，在煤田内形成大量NNE-SSW方向正断层。根据两淮地区不同井田层滑构造的地质原型和力学机制，设计不同边界条件的构造物理模拟实验，以相似性原则作为约束条件，开展了不同类型层滑构造的模拟实验，深入研究层滑构造的力学机制，揭示层滑构造的演化过程和主控因素，预测层滑构造对煤层的影响，为煤矿开采部署提供参考依据。