Study On The Effect Of Overburden Rock Deformation Factor By The Synergy Between Tectonic Field And Mining Stress Field

This essay adopts the main shaft coal bunker of Hebi No.8 coal mine as the engineering application background, and uses theoretical analysis, rock mechanics parameter test, similar material simulation experiments,numerical experiments and field tests and other research methods,it analyzes and researches movement and deformation and destruction rule of the overburden rock under the synergy of tectonic stress field and mining-induced stress field.The overburden rock complicated space curved surface is separated,using the theory of differential geometry,calculate a point of maximum and minimum principal curvature radius,in combination with the thickness of the overburden rock and mechanical parameters,tectonic principal stress can be obtained.In order to more accurate calculate mining-induced stress,four factors of affecting the prediction accuracy is optimized.①The size of the mining micro unit,established by the method of numerical experiments of the side length d of mining micro units and mining face length L and specific value of depth and thickness D as functional relationship;②Through the mining face contour line of coal seam floor fitting space curved surface equation.On this basis,it obtained angle and trend of mining micro unit centroid point.Then acquires mining micro unit influence on the movement and deformation of the overburden rock;③Using six node triangular finite element method to expect coal thickness of mining micro unit centroid point.④Through numerical experiment method,according to the different GSI values,calculates mainly the size of the radius of influence of the overburden rock in different elevation. Fitting the function relation between index n of the main influence radius and comprehensive crush resistance cR.The mining stress according to the coordinate axis rotation method,transforms to coordinate axis is based on tectonic principal stress in the new coordinate system,after a complex mathematical operations,and makes the stress in the two coordinate system transforms into the stress in the same coordinate system,according to the rule of D-P to judge damage area and stress of a specific point of the overburden rock.Using similar material simulation experiment for validation,error between mining-induced stress in inclination direction of coal bunker and similar material simulation results is 12.6%,vertical direction error is 19.0%.Calculates the synergy of tectonic stress and mining-induced stress, error of trend direction of coal bunker is 5.2~23.8%;error of tendency direction is 1.2~10.3%.Using of D-P standard to judge without damage at coal bunker,conform to field measurement.