| Coal is an important strategic resource and major energy source in China,and how to mine the Yining coalfield,as one of the important undertaking areas and strategic reserve areas for the westward shift of coal productivity in China,is an important topic for the future.In this thesis,we summarize and analyze the tectonic characteristics and tectonic evolution stages of Yining coalfield,evaluate the tectonic complexity of the study area,simulate the state of representative coal seams in the study area under multiple mining,and summarize the influence of different structures on coal mining in the study area.The results of the study will aim to provide a reliable geological and theoretical basis for the protective development and mining of coal resources in the Yining coalfield.Combining the regional tectonic background and the tectonic evolution of the neighboring areas,this thesis divides the tectonic evolution of the study area into four stages:Haixi-Indian,Early-Middle Yanshan,Late Yanshan-Himalayan Act I,and Himalayan Act II-Present,and discusses the tectonic evolution and stress characteristics of each stage separately.The study shows that the tectonic deformation in the study area is dominated by extrusion and uplift,and is influenced by the Yanshan phase tectonic movement,and has suffered from multiple phases of extrusion and multiple phases of tensional fracture and uplift denudation.In this thesis,we collected geological data of the study area,summarized the characteristics and laws of tectonic development in Yining coalfield,and selected two evaluation indexes of similarity dimension and entropy function in fractal fractal theory to quantitatively evaluate the complexity of geological structure in the study area.The evaluation results show that the tectonic complexity of the study area is mainly more complex tectonics,and there are two tectonically complex areas in the north and east of the study area,while the tectonically simple areas are mainly distributed in the central part of the study area,and the tectonics gradually become complex from the central part to the north and south sides.Using FLAC3Dmodeling software,the present-day state of the Panjin coal mine in the Yining coalfield in the Yibei mining area after multiple phases of tectonic evolution is used as the basis for numerical simulation analysis of the area.The simulation aims to reveal the deformation and damage patterns of the rock layers in the space above and below the coal seam caused by mining in the coal seam in the tectonically developed area,especially multiple mining,and to provide a basis for further mining of the coal seam.The changes of displacement,stress and plastic zone of coal seams in the simulated area after sequential mining are systematically analyzed.The control of different scales of tectonics on the coal seam assignment in Yining coalfield is systematically analyzed to reveal the control of multi-scale,multi-level and multi-style tectonics on the coal seam assignment.The influence of different tectonic styles,such as folds,faults and other factors on coal mining in the study area is summarized and analyzed. |
