Numerical Simulation On Coal-rock Viscoelastoplasticity Deformation In Mining Process

The original stress distribution of coal-rock is destroyed in the mining process, and the speed of deformation damage is increasing by the creep properties of coal. Then it is significant to research the coal-rock creep properties, stress distribution and displacement variation in the mining process for prevention of disaster such as roof falling and gas outburst.The purposes of this paper is to simulate Viscoelastoplasticity of coal-rock in the mining process using ABAQUS software, considering the relationship between creep properties and mining process. The suitable constitutive model is selected through comparison of merits and demerits of the ABAQUS models and the accuracy of Drucker-Prager models is verified through examples. The simplified 2d finite element model of coal-rock is created. The numerical results of Drucker-Prager models and Drucker-Prager creep models are calculated respectively, then main results are drawn as follow:(1) The Drucker-Prager creep model of ABAQUS is suit for the simulation of coal-rock mining.(2) The deformation of coal-rock and the variation of creep strain in mining process are simulated by using ABAQUS software. Two different areas are showed in vertical stress distribution of roofs. The first area is the distressed zone above gob. The stress value is increasing with the rising of height of stress arch. The second area is the high stress area located in both side of gob. In early stage, the smaller displacement arch is formed in roofs, with a V-shaped deformation of roofs. The roofs squeezed completely in the end of mining with the U-shaped deformation of roofs. The creep value of coal-rock is increasing by the time increase, according to displacement. The strain value varies located on the top of roof of initial mining area. (3) The stress and variation of displacement are conformed to the phenomenon in references; therefore the simulation results are accurate.