Research On The Damage And Fracture Of Coal Based On Catastrophe Theory

With the continuous development of science and technology,energy efficiency is also increasing.China’s coalbed methane production in twenty-first Century has exceeded 10 billion cubic meters,which represents China’s coal-bed methane has been in a period of rapid development.And The important technical means to improve coalbed methane production is hydraulic fracturing.In order to exploit coalbed methane more efficiently,this paper studies the relationship between hydraulic fracturing of coal rock mass and the brittleness of coal and rock mass from the angle of coal rock mass brittleness and sudden fracture of coal rock mass.The main contents of this paper are as follows:(1)In this paper,the present situation of the research on the damage and fracture of coal and rock mass,the numerical simulation of rock deformation and failure,the acoustic emission of rock mass and the theory of catastrophe are studied.The advanced technology and theory of rock mass failure and rock burst at home and abroad are reviewed.(2)In this paper,the research methods and theory of brittle rock mass are introduced,the method based on the full stress strain curve is widely used.In this paper,based on the damage evaluation method based on Jiang Dongfeng’s theory,the brittleness index of rock mass is studied and evaluated.(3)According to the numerical simulation of the 12 RFPA2D-Basic version of soft coal and rock samples under uniaxial compression,we can get different coal and rock stress-strain curve,the stress-strain curve and the brittle index above the uniaxial compression of rock brittleness are different.Based on the study of acoustic emission signal and energy of different brittle rock mass,the relationship between the brittleness and acoustic emission of coal and rock mass is studied.(4)Combining the brittleness index theory to establish catastrophe model of coal and rock damage folding and mutation,and according to the coal rock damage model of catastrophe damage energy release model of coal and rock.Through the RFPA2D-Flow numerical simulation software,simulation of hydraulic fracturing numerical 12 coal rock samples,according to the hydraulic fracturing simulation results of different coal and rock brittleness,can be obtained: The greater the brittleness of rock mass is,the more complex fracture network will be formed by hydraulic fracturing of coal rock mass.Analysis of bedding and the effect of confining pressure on rock hydraulic fracturing,the results shows that bedding angle is large,the smaller the pressure,the greater the brittleness of coal rock mass hydraulic fracturing of coal and rock,it is easier to form more branch fracture and complex fracture network.