循环荷载作用下煤变形与能量演化规律试验研究  

EXPERIMENTAL STUDY OF DEFORMATION AND ENERGY EVOLUTION LAW OF COAL UNDER CYCLIC LOADING

作　　者：许江[1,2] 李波波[1,2] 周婷[1,2] 刘东[1,2] 曹偈[1,2] 叶桂兵[1,2] 

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室,重庆400044

出　　处：《岩石力学与工程学报》2014年第A02期3563-3572,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：重庆市基础与前沿研究计划项目(cstc2013jj B90001);国家科技重大专项资助项目(2011ZX05034–004);国家重点基础研究发展计划(973)项目(2011CB201203)

摘　　要：利用自主研发的含瓦斯煤岩热流固耦合三轴伺服渗流装置,以型煤试件为研究对象,进行不同温度条件下循环荷载试验研究,研究循环荷载作用下煤变形与能量演化规律。研究结果表明:(1)轴向吸收能U1随轴向应力增加逐渐增大,主要转化为弹性应变能Ue1释放和径向回弹变形做负功消耗能U3,以及用于卸载阶段塑性变形及新生裂纹耗散能Ud,同时围压产生的径向弹性应变能Ue3补充进来。(2)加载段吸收能U为正,煤从外载荷吸收能量,随着循环次数的增加而逐渐减小,经历第1次循环到第2次循环突降的阶段后逐渐趋于稳定。在同一循环周期下,加载段吸收能随温度的升高逐渐减小,70℃下最稳定。(3)轴向耗散能Ud1、径向耗散能Ud3的绝对值、耗散能Ud均随着循环次数的增大而减小,并逐渐趋于稳定值。(4)加卸载耗散能Ud、可释放的弹性应变能Ue的绝对值转化速率均随温度的升高而减小,而加载段3做负功消耗能U3的转化速率变化不大,三者随循环次数的增大有减小趋势,且Ue释放速率的绝对值比Ud耗散速率、U3消散速率的绝对值均快。Based on the self-developed triaxial servo-controlled seepage equipment for thermal-hydrologicalmechanical coupling of coal containing methane,the experimental study of cyclic load of coal was performed on coal samples under different temperatures. The results are shown as follows：（1） The absorbed energy in axial direction U1 increases with the increase of axial stress,its converted into elastic strain energy Ue1 and consumed energy for radial deformation U3,and the dissipated energy Ud for plastic deformation or cracks in unloading stages,the radial elastic strain energy Ue3 produced by confining pressure is supplemented at the same time.（2） The absorbed energy U is positive,it decreases gradually with the increase of the cycle index,and it begins to flatten after the sudden drop between the first and the second cycle. In the same cycle,U decreases with the temperature increase,and it is the most stable in 70 ℃.（3） The absolute value of axial dissipated energy Ud1,radial dissipated energy Ud3 and the dissipated energy Ud decrease with the increase of the cycle index,and tend to stably.（4） The absolute value of conversion rate of Ud and Ue decrease with temperature increase,but the conversion rate of U3 has not changed much,the three forms of energy all decrease with increase of cycle index,and the absolute value of releasing rate of Ue is faster than Ud and U3.

关 键 词：岩石力学 循环荷载 温度 变形 能量 

分 类 号：TU43[建筑科学—岩土工程]