| With the increase of coal mining depth,the working face is faced with more complex hydrogeological conditions,resulting in frequent floor water inrush accidents,which seriously threaten the safe and efficient coal production.Hidden faults are a kind of common fault structures in deep strata.Compared with penetrating faults,hidden faults have small drop,large number,random development location,and difficult to be ascertained.Therefore,it is more likely to cause floor water inrush accidents under the influence of mining.Therefore,it is very important to study the water inrush mechanism of coal seam floor with hidden fault fracture zone for safe and efficient mining of deep coal resources.In this thesis,by means of field investigation,laboratory test,theoretical deduction and numerical simulation,the seepage-creep coupling properties of hidden fault rock mass and its influencing factors were studied,and the whole process of coal seam floor water inrush was reproduced,providing experimental and theoretical basis for the prevention and treatment of floor water damage in the fracture zone with hidden fault.The main research results are as follows:(1)Seepage-creep coupling properties test of hidden fault rock mass was carried out.Seepage-creep coupling test system of fault rock mass was specifically developed,and seepage-creep coupling properties tests of hidden fault rock mass under different conditions were designed.The water inrush process of floor was divided into two periods: compression creep period and expansion failure period,and the influences for different factors on the water inrush characteristics of floor were analyzed.(2)Seepage-creep coupling theoretical model of hidden fault rock mass was constructed.According to the water inrush characteristics of hidden fault rock mass in coal seam floor,creep constitutive equation,stress field control equation,seepage field control equation and seepage-creep coupling auxiliary equation were established,and seepage-creep coupling theoretical model of hidden fault rock mass was obtained by coupling their relations.(3)Laboratory scale simulation of seepage-creep coupling properties of hidden fault rock mass was carried out.COMSOL MULTIPHYSICS software was used to solve and calculate the theoretical model.The simulation results were compared with the test results to verify the reliability of the model.On this basis,the temporal-spatial evolution laws for seepage-creep coupling properties of the hidden fault rock mass were obtained.(4)Engineering scale simulation of seepage-creep coupling properties of hidden fault rock mass was carried out.Based on geological conditions of No.3 coal seam in a mine,the simulation research on engineering scale was carried out to predict the characteristics of water inrush of hidden fault rock mass in coal seam floor,and the water inrush prevention and treatment schemes were proposed according to the prediction results.The thesis has 48 figures,9 tables,and 99 references. |
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