Construction Of In-situ Stress Database And Study On Factors Influencing In-situ Stress Distribution In Coal Mine

There are 1357 items in-situ stress data of China coal mine collected in the paper,including 406 items stress relief data and 951 items hydraulic fracturing data and the whole data is based on the in-situ stress data measured by CCRI.On the basis of the data,the paper presented the "database of stress environment in China coal mine" and conducted detailed research on the factors influencing in-situ stress distribution by methods of theoretical analysis,mathematical statistics and numerical simulation.In addition,the paper conducted a preliminary exploration on insitu stress back analysis in typical coal mine.Through a series of study on this paper,the following results can be obtained:(1)Based on the in-situ stress data collected in coal mine,The "database of stress environment in China coal mine" has got construction.The in-situ stress data in coal mine can be searched quickly and accurately,and the results are displayed in the form of earth stress map.The map of crustal stress and the map of crustal stress in China coal mining area were drawn.(2)The scattered points of several typical characteristic parameters in coal mine with depth were established and analyzed.Among them,the linear regression formula of maximum and minimum horizontal principal stress and vertical stress with depth can be:The regression formula of the ratio of maximum,average and minimum horizontal principal stress to vertical stress with the depth can be:(3)The paper selected 42 items siltstone stress data,136 items fine sandstone stress data,99 items shaly sandstone stress data and 90 items mudstone data,and made the maximum and minimum horizontal principal stress regression analysis,horizontal shear stress regression analysis with the depth and the ratio of average principal stress to vertical stress regression analysis with the depth.(4)The paper selected 77 items data which contain coal and rock elastic modulus and Poisson's ratio,and established multiple linear regression formula of maximum and minimum horizontal principal stress and vertical stress with depth and elastic modulus:?H=0.0015 + 0.0366H + 0.015E;?h=0.024 + 0.0186H-0.00099E;?V=0.327 + 0.0226H-0.01065E.The paper also established multiple linear regression formula of horizontal shear stress and the maximum principal stress difference with depth and the elastic modulus:?1-3 = 0.275 + 0.018H + 0.0205E.And by multiple regression and analysis,the paper made a parameter correction to the ratio of the average principal stress to the vertical stress presented by Sheorey model.(5)In the coal mine,the relationship and criterion between in-situ stress and fault slip is discussed and the paper gave three models on the criterion between in-situ stress and fault slip:maximum and minimum horizontal principal stress for normal and reverse fault mode,maximum principal stress difference for three types fault mode and Mohr stress circle critical tangent mode.(6)Selecting Changcun Coal Mine as the background,the paper made a preliminary in-situ stress back analysis on research region by numerical simulation.The measured stress and numerical simulation results are in good agreement.At the same time,according to the result of stress back analysis the paper analysed the tectonic stress field which be impacted by faults and folds geological structure.