Mechanical Properties And Establishing Of Constitutive Relation Of Coal Rock In13_-1 Coal Seam From Panxie Coalfield Under Impact Load

Selecting coal rock in13-1coal seam from Panxie coalfield as research object, the dynamic mechanical properties and constitutive relation of gas coal is studied through combined method of experiment, theoretical analysis and numerical simulation.The uniaxial impact compression test of coal rock in13-1coal seam from Panxie coal field is executed under several strain rates by using SHPB, test data including wave form and degree of crushing is collected, and dynamic relation curves of stress and strain is obtained by three-wave method. The test results show that dynamic strength, dynamic elastic modulus and degree of crushing are insensitive to strain rate, gas coal have dynamic mechanical properties such as strain hardening and strain-rate hardening.Based on gas coal dynamic mechanical, the dynamic constitutive equation of gas coal is established through modifying Z-W-T constitutive equation and instructing damage variable. Being obtained through data fitting, the constitutive parameters indicate that coal rock is sensitive to the response of the high strain rate, and under high strain rates gas coal characterizes brittle feature more obviously than anthracite. The fitting curves coincide with the experiment curves well.According to the dynamic constitutive equation, VUMAT subroutine is developed by using FOTRAN language, and the finite element model of SHPB is created. The simulation results show that the dynamic constitutive equation of coal rock can reflect the gas coal’s dynamic stress-strain relation before peak stress well.