The Tectonic Evolution And Its Effect On Mine Structure Of Panguan Syncline

The tectonic evolution of the Panguan syncline has a significant control effect on the development of coal well structure,and the development degree of the mine structure has a profound influence on the safe and efficient production of the coal mine.Therefore,on the basis of the collection,collation and regional geological structure characteristics and evolution analysis of mine geological data system,this paper analyzes the paleo tectonic stress field by the field structural observation and analysis,the structural rock and structural coal microscopic deformation characteristics and the stress strain ring boundary analysis and the complexity of the mine's structural complexity.The formation and evolution mechanism of the Panguan syncline and its control on the structural development of the mine are discussed.The following research results have been achieved:(1)The Panguan syncline is located in the middle of the block NE to the blocking fold area,with a NE to the extended short axis open skew inclined oblique,its SE wing is slow,the dip angle is 15-20 degrees,the extension is stable,the structure deformation is weak,the NW wing is steepy,the general rock dip angle is 25-45 degrees,the local erect or the inversion.It has the overall structural characteristics of "block interphase,complex combination,basement control and multi-stage superposition".(2)The structure and structural deformation characteristics of the Panguan syncline are discussed.The extension of NE-SW to the main Hercynian period formed NW to the Youjiang fault and the Zhao Zi River fault,which formed the north and south boundary of the study area and restricted the development of the late syncline.The average direction of the maximum principal stress sigma 1 at the Indosinian period is 27 degrees,which mainly causes the early NW fault to squeeze and shear,and forms the Yan Wu Zhai syncline and the Xiao Zhu Qing anticline near the fracture NW direction.The tectonic movement in the Yanshan period is the most intense,the maximum principal stress,sigma 1,is 339 degrees,forming a large fold and fracture in the area of NNE-NE,which plays a key role in the formation of the structural form in the study area;and the movement in Himalaya is still strong and the maximum principal stress in the region is 83 degrees in the 1 direction,which makes the Panxian fault strong right.The movement of walking and sliding caused the secondary folds in the northern part of the Panguan syncline and the right spin shear broom like structure in the northern part of the syncline,and made the NW Youjiang fault sinistral strike slipping,causing the curved bend of the southern part of the syncline in the southern part of the Panguan syncline.(3)The most developed high angle conjugate shear joints in the study area are the most developed with NW direction,followed by NNE direction and near EW direction,reflecting the role of the tectonic stress field in the study area with multiple stages and different directions.On the basis of the observation and analysis of the mechanical properties of the joints,the palaeo tectonic stress field is restored through the intersecting relationship between the joint groups,and the paleo tectonic stress field is restored.The microscopic deformation characteristics of the tectonic rocks show that the micro deformation structure is mainly brittle deformation,such as shear and tensional fracture,and the plastic deformation is weak,and the shear fracture is more straight and prolonged.The extensional cracks are filled with calcite,and the cracks are cut and restricted by each other.The microstructure deformation characteristics of the coal are found to be weak,mainly brittle,and the ductile deformation is only partly visible.(4)Using the fractal theory,the mesh method is used to calculate the value of the fracture capacity of the moon field mine,the mountain foot tree mine,the fire paking mine and the golden fine mine by the grid covering method.According to the fracture capacity dimension contour line,the complexity of the fault development of each mine is analyzed.It is found that the fault capacity dimension area is mainly distributed in the large and medium faults and the inverse.In the vicinity of faults,the development of large and medium faults is weak in the low value area,which reflects that the larger strata are the key factors affecting the complexity of the mine structure.