| The rock mass in nature is a fractured rock mass composed of rock blocks and cracks.The seepage law of fractured rock mass under real condition has always been a hot issue in the field of rock hydraulics.The fractured rock mass in the goaf of coal mine is a rock mass with large space structure,its seepage problem is directly related to the safe operation of coal mine and the protection of groundwater resources in the mining area.It is also an important issue that needs to be deeply studied in the seepage problem of fractured rock mass.Based on the seepage theory of fractured rock mass,in this paper,the discrete element software UDEC and 3DEC were used to simulate the coal mining step by step in the rock mass of Daliuta,and using the idea of digital image finite element,building the background mesh which is consistent with the output image of the numerical calculation by discrete element software.By the way,the finite element model is reconstructed to calculate the seepage flow,studying the Variation law of seepage characteristics of fracture rock in caving zone and water flowing fractured zone before and after coal minning.This paper puts forward a kind of thought of solving the seepage calculation after the excavation of rock mass.The finite element reconstruction of discrete element model is realized by this method,besides in the method,the advantages of finite element software in simulating the collapse of rock mass and the advantages of finite element software in the calculation of stress seepage are fully utilized.Combining the two advantages together,it is very good to solve the problem of numerical simulation of the process of the excavation failure of the underground rock mass,the stress of the front and back,and the seepage law.The results achieved in this paper are as follows:1 Based on the related formation lithology and geological data,the 2D and 3D discrete element model of fractured rock mass containing 2-2 coal and overlying strata in the coal mine is established.This is the foundation of the numerical calculation of the fractured rock mass model,and studying the strength characteristics,deformation characteristics and seepage characteristics of rock mass structure and the rock mass response under the coupling action of seepage and stress.By means of two dimensional discrete element simulation of the geological model,the fracture development of a coal mining area in the process of fractional step mining is determined,meanwhile,the development height of caving zone and water flowing fractured zone as well as the deformation and settlement process of the midpoint of the ground surface during the process of excavation are determined.2 Using image processing technology to calculate the void ratio and the void space along the height of the bottom slab of the goaf in a rectangular space,offering the basic parameter calculation for the calculation of the storage capacity of underground reservoir water level curve.3 According to the digital image finite element technology ideas,through the background grid method,using MATLAB programming to realize coal seam mining rock mass of discrete element model outputs image reconstruction after conversion for finite element mesh model of the rock mass.Studying the seepage law of the large space rock mass structure formulated after mining by using the finite element calculation software ABAQUS. |
PDF Full Text Request