脉动孔隙水压下煤岩损伤变形的能量观点分析  

Energy analysis of coal damage deformation under pulsating pore water pressure

作　　者：朱红青[1,2] 张民波[2] 顾北方 申翔[2] 

机构地区：[1]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083 [2]中国矿业大学(北京)资源与安全工程学院,北京100083

出　　处：《中南大学学报（自然科学版）》2014年第10期3657-3663,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金重点资助项目(U1261214);国家自然科学基金资助项目(51074168)~~

摘　　要：采用RLW-2000M微机控制煤岩流变仪进行三轴加压状态下脉动孔隙水压作用于煤岩的实验研究。研究结果表明:煤岩在脉动水压作用下的残余应变具有初期变形较大、后期变化较小且平稳的特征,其变化趋势符合负指数幂规律。基于热力学定律,采用能量观点将单个滞回曲线加、卸载过程中的4个阶段进行能量吸收与能量释放的划分,其变化规律分别为Uab逐渐减小、Ubc逐渐增加、Ucd变化不稳定和Ude逐渐减小。同时,单个滞回曲线总能量的变化是能量耗散的过程,具有初期变化较大、后期逐渐降低的趋势,与残余应变特征相对应。脉动水压上限越大,能量耗散越大,煤体内部损伤和塑性变形越大,强度丧失越多。从能量的角度解释了脉动水压作用下煤岩损伤变形的过程,为现场施工煤层脉动注水提供了一定的理论参考依据。The experimental study of pulsating pore water pressure acting on coal was done in the triaxial compression state by using the RLW-2000 coal rheometer controlled by microcomputer. The results show that the residual strain of samples is big at the initial stage and uniform at the latter stage, which follow negative exponential law. Based on the thermomechanics law, the loading and unloading process of a single hysteresis loop curve is divided into four stages of energy absorption and energy release by using energy principle. And the characteristics of four stages are as follows：decreasing in the Uab phase, increasing in the Ubc phase, and fluctuating in the Ucd phase and decreasing in the Ude phase.At the same time, the total energy change of a single hysteresis loop is a process of energy dissipation and it is big in the initial phase and small in the later phase, which is consistent with the characteristics of residual strain. The amount of energy dissipation is greater when the water pressure is bigger, which indicate that damage and plastic deformation are bigger. The damage and deformation process of coal acted by pulsating water pressure is explained from energy view,which provide certain theoretical reference for on-site construction.

关 键 词：脉动孔隙水压 损伤变形 残余应变 能量吸收 能量释放 强度丧失 

分 类 号：TD712[矿业工程—矿井通风与安全]