复合煤岩循环加卸荷红外辐射及能量演化特征

Infrared radiation and energy evolution characteristics of cyclic loading and unloading of composite coal and rock

为了深入分析循环加卸荷过程中复合煤岩能量演化特征,以平庄煤业集团风水沟矿为研究对象,利用三轴试验机和长波热像仪对复合煤岩在不同加卸荷速率下进行循环加卸荷试验并实现红外辐射监测,得到复合煤岩在加卸了过程中各部分表面平均红外温度变化,研究了不同加卸荷速率下弹性能密度、耗散能密度随温度及轴向载荷变化的规律,确定了总能量、弹性能和耗散能与轴向载荷和红外辐射温度之间的拟合关系。结果表明,煤岩红外辐射温度变化分为起始升温、温度平稳、温度骤降和快速升温4个阶段,其中快速升温阶段各能量增长速率最大。总能量、弹性能、耗散能与轴向载荷、煤体红外辐射温度高度相关,可以采用非线性曲线较好地拟合。研究成果为采用红外辐射温度变化法来分析循环加卸载过程中煤岩能量演化特征提供了依据。

In this paper,energy evolution was used as a variable to study the energy evolution mechanism in the process of rock deformation and failure,and the average infrared temperature and energy evolution law in the process of loading and unloading were analyzed.The research object was the composite coal rock with the combination ratio of 1:1:1 in the Fengshuigou coal mine of Pingzhuang Coal Industry Group.The cyclic loading and unloading tests of coal and rock under different loading and unloading rates were carried out by the TAW-2000 rock triaxial testing machine,and the infrared radiation temperature of coal and rock surface was detected by longwave thermal imager FLIR SC7000.The results show that:(1)with different loading and unloading rates,the variation trend of the average surface temperature of coal and rock mass is the same.There are four stages:initial temperature rise,stable temperature,sudden temperature drop,and rapid temperature rise.The temperature change of coal is more obvious than that of rock.The higher the loading and unloading rate is,the greater the temperature rises in the rapid heating stage.(2)Each energy increases with the increase of axial load.But the difference is that the elastic energy density presents a steady increasing trend while the increasing rate of the dissipative energy density gradually accelerates.The higher the loading rate is,the greater the dissipated energy and the higher the temperature rise.(3)Each energy has a quadratic correlation with the axial load,and the correlation coefficient is above 0.98.Each energy has a three times correlation with the infrared radiation temperature of coal,and the correlation coefficient is above 0.88.The energy growth rate of infrared radiation temperature increases greatly in the rapid heating stage after the sudden drop.Therefore,the trend of energy change can be judged by measuring the infrared radiation temperature,and then the current mechanical state can be obtained,which provides a new method for non-contact dynamic disaster prediction.