摘要
为了探求煤层冲击倾向性鉴定时循环加卸载中滞回环与弹塑性应变能的关系,利用电液伺服试验机对煤样进行单轴循环加卸载试验。对试验所得循环加卸载应力–应变曲线、循环次数与滞回环面积曲线、弹性应变能与滞回环面积关系等进行分析。得出结论如下:(1)随着循环次数的增加,循环次数和弹性应变能与滞回环面积呈正相关。(2)滞回环产生于循环加卸载过程的压密阶段。当煤样接近破坏时,压密阶段的不可逆塑性形变达到最大。(3)每一次循环的塑性能是新生成裂纹的耗散能,以往的弹性能量指数计算中未将压密裂纹形成的耗散能(滞回环面积)去掉,导致指数计算结果偏小,因此提出弹性能量指数修正计算公式。提出的修正公式可使煤层冲击倾向性鉴定时的弹性能量指数计算更精确。
Uniaxial cyclic loading and unloading experiments for coal samples were performed using electro-hydraulic servo testing machine in order to obtain the relationship between the hysteresis loop and elastoplastic strain energy under cyclic loading and unloading for identifying the burst tendency of coal. The stress-strain curves,the curves of loading cycles against the loop area of hysteresis and the relationship between the elastic strain energy and the loop area of hysteresis were analyzed. The loop area of hysteresis and the elastic strain energy were found to be positively correlated with the circle numbers. The hysteresis loop occurred in the compression phase of the cyclic loading and unloading. When the coal sample was approaching the failure,the irreversible plastic deformation achieved the maximum value. The plastic energy of each cycle was found to be the dissipated energy of the newly generated cracks. The dissipated energy（hysteresis loop area） was not subtracted in calculating the elastic energy index in the previous methods,which led to smaller values. The index formula was thus modified for better predicting the burst tendency of coal.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2014年第9期1791-1797,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
教育部科学技术研究重点资助项目(210064)
国家自然科学基金资助项目(51374097)
关键词
岩石力学
弹性应变能
滞回环
循环次数
滞回环面积
rock mechanics
elastic strain energy
hysteresis loop
cycle numbers
area of hysteresis loop
