Compared to intact coal,tectonic coal exhibits unique characteristics.The deformation behaviours under cyclic loading with different confining pressures and loading rates are monitored by MTS815 test system,and the me...Compared to intact coal,tectonic coal exhibits unique characteristics.The deformation behaviours under cyclic loading with different confining pressures and loading rates are monitored by MTS815 test system,and the mechanical and energy properties are analysed using experimental data.The results show that the stress-strain curve could be divided into four stages in a single cycle.The elastic strain and elastic energy density increase linearly with deviatoric stress and are proportional to the confining pressure and loading rate;irreversible strain and dissipated energy density increase exponentially with deviatoric stress,inversely proportional to the confining pressure and loading rate.The internal structure of tectonic coal is divided into three types,all of which are damaged under different deviatoric stress levels,thereby explaining the segmentation phenomenon of stress-strain curve of tectonic coal in the cyclic loading process.Tectonic coal exhibits nonlinear energy storage characteristics,which verifies why the tectonic coal is prone to coal and gas outburst from the principle of energy dissipation.In addition,the damage mechanism of tectonic coal is described from the point of energy distribution by introducing the concepts of crushing energy and friction energy.展开更多
基金funded by the National Major Scientific Research Instrument Development Project(No.41727801)the National Natural Science Foundation of China(Nos.42030810 and 41972168)+1 种基金the Dominant discipline support project of Jiangsu Province(No.2020CXNL11)the Foundation of Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization(No.2019A001).
文摘Compared to intact coal,tectonic coal exhibits unique characteristics.The deformation behaviours under cyclic loading with different confining pressures and loading rates are monitored by MTS815 test system,and the mechanical and energy properties are analysed using experimental data.The results show that the stress-strain curve could be divided into four stages in a single cycle.The elastic strain and elastic energy density increase linearly with deviatoric stress and are proportional to the confining pressure and loading rate;irreversible strain and dissipated energy density increase exponentially with deviatoric stress,inversely proportional to the confining pressure and loading rate.The internal structure of tectonic coal is divided into three types,all of which are damaged under different deviatoric stress levels,thereby explaining the segmentation phenomenon of stress-strain curve of tectonic coal in the cyclic loading process.Tectonic coal exhibits nonlinear energy storage characteristics,which verifies why the tectonic coal is prone to coal and gas outburst from the principle of energy dissipation.In addition,the damage mechanism of tectonic coal is described from the point of energy distribution by introducing the concepts of crushing energy and friction energy.
