Deep Soft Coal And Rock Roadway Deformation Law Of Creep And Numerical Simulation

With the increase of coal mining scale,most of the country of mining depth of more than 800 m,while 70% is disposed of deep roadway in soft coal seam.Soft rock roadway and general different,because buried deep,soft coal with the help of two broken loose and the presence of tectonic stress with the help of the Ministry of coal and rock deformation and render large strong rheology,difficulty and problems caused by deep mining,is China’s coal industry have to face the problem,studies show: deep rock has sustained strong rheological properties,the performance of large deformation,long duration,which has a significant time effect.Therefore,the use of scientific research methods on the creep characteristics and variation of deep soft rock of coal research,to solve theoretical and practical engineering project and double the value of the creep-related issues.Based on a comprehensive analysis of domestic and foreign rock creep testing machine and creep numerical simulation,carried out the following studies and draw some conclusions:(1)using the SD-20 instrument for rock creep grade coal and rock uniaxial loading and unloading creep compression test,and obtain creep parameters of coal by nonlinear fitting.Through the analysis of coal and rock uniaxial compression creep test curve,you can see:at lower stress levels,coal and rock specimens transition from the initial stage and quickly into stable creep stage,when the stress level exceeds its yield the limit,the rock comes into the constant creep stage,the strain increases with time going by,if the strain value exceeds its limit strain value,the specimen will damage;sectional shape of the roadway has the greater inpact on roadway displacement,the displacement of rectangular roadway largest,followed by a curved wall and circular roadway minimum;(2)Using the finite difference software FLAC3 D select Moore-CVISC creep model of Coulomb expansion model simulation under different conditions(different stresses,different lithologies)deep creep weak variation of coal and rock roadway surface.The simulation results show that: with the increase of stress levels,displacement of roadway roof,floor and help section is gradually increased depth deeper roadway surface vertical stress increases within a certain time,the growth rate first increases and then decreases lithology worse the conditions,the greater the amount of deformation.Creep deformation is the main form of deep tunnels with high stress damage;(3)The monitoring points are arranged in a certain direction of the roadway gangs,and the displacement gradient is used to judge the variation rule of the creep stage.The results show that the displacement gradient of the horizontal strata in the horizontal direction of the roadway is different from that of the loosening circle,and the relationship between the high stress,the large section and the lithology of the roadway with different stress level,different section size and different lithology conditions The time required for the rock to reach the creep stability is longer.At different creep times,when the displacement gradient is 0.002,the displacement of the surrounding rock is in the constant creep stage,and when the stabilization phase is greater than the displacement gradient Can be used to determine the roadway into the accelerated creep stage,through the displacement gradient can reflect the size of the roadway loosening circle,when the loosening circle size increases in the rate of 0.003 m / d,you can determine the development of roadway loosening basically in a stable stage.