真三轴循环载荷作用下煤岩力学及损伤特征试验研究  

Experimental study on mechanical and damage characteristics of coal under cyclic true triaxial loading

作　　者：段敏克 蒋长宝[2] 郭现伟[3] 杨科[1] 张向阳[1] 马海峰[1] DUAN Minke;JIANG Changbao;GUO Xianwei;YANG Ke;ZHANG Xiangyang;MA Haifeng(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan,Anhui 232001,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400030,China;Jining No.3 Mine,Yanzhou Coal Mining Corporation Ltd.,Jining,Shandong 272169,China)

机构地区：[1]安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南232001 [2]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400030 [3]兖州煤业股份有限公司济宁三号煤矿,山东济宁272169

出　　处：《岩石力学与工程学报》2021年第6期1110-1118,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：安徽高校自然科学研究项目重点项目(KJ2020A0325);国家自然科学基金资助项目(52074044,51674048)。

摘　　要：为了研究煤矿采掘过程中真三轴循环扰动应力对煤岩力学特征的影响,利用GCTS真三轴力学试验系统,开展分级循环中间主应力σ2下的煤岩力学试验研究,分析分级循环σ2对煤岩变形、能耗及损伤特征的影响,揭示真三轴循环过程中的中间主应力效应。研究结果表明:分级循环σ2对中间主应变ε2和最小主应变ε3的影响明显大于最大主应变ε1。随着最小主应力σ3值增加,分级循环σ2引起地ε1和ε3都明显降低。循环加或卸载σ2都可引起煤岩的失稳破坏,且当σ3较小时,煤岩倾向于在σ2卸载至靠近σ3的过程中发生破坏,而当σ3较大时,煤岩倾向于在σ2加载至靠近最大主应力σ1的过程中发生破坏,但破坏时对应的σ2逼近率相近都在70%左右。σ2的加载和卸载作用对煤岩的残余变形甚至破坏具有等效性。随着分级循环σ2幅度的增加,煤岩的总耗散能呈"指数型"增加,煤岩的损伤变量呈现明显的"减速→加速→再减速"的S型变化趋势。分级循环σ2过程中的煤岩平均安全损伤变量阈值为Dc=0.9。To study the influence of true triaxial cyclic disturbance stresses on the mechanical characteristics of coal in the process of mining and excavation,the coal mechanical experiment under the intermediate principal stress(σ2) of tiered cycle is carried out based on GCTS true triaxial mechanical experiment system,and the influence of σ2 on deformation,energy consumption and damage characteristics of coal is analyzed. The results show that the effect of tiered cyclic σ2 on ε2 and ε3 is greater than that on ε1. With increasing σ3,both ε1 and ε3 decrease significantly. Cyclic loading or unloading of σ2 can cause instability and failure of coal. When σ3 is small,coal tends to be destroyed in the process of σ2 unloading to close to σ3,and when σ3 is large,coal tends to be destroyed in the process of σ2 loading close to σ1. However,the approximation rate of σ2 corresponding to failure is similar,all around 70%. The loading or unloading of σ2 has equivalent effect on the residual deformation and even failure of coal. With increasing the amplitude of tiered cyclic σ2,the total dissipation energy of coal increases exponentially,and the damage variable of coal presents an obvious S-type change trend of deceleration, acceleration and re-deceleration. The threshold value of the average safety damage variable of coal and rock is 0.9 in the process of tiered cyclic σ2.

关 键 词：岩石力学 原煤 循环中间主应力 残余应变 能量耗散 损伤变量 

分 类 号：TU45[建筑科学—岩土工程]