卸荷与补偿路径下深部岩体力学特性与变形破坏特征  

Mechanical properties and deformation damage characteristics of deep rock under unloading and compensation paths

作　　者：戚敏杰 赵光明[1,2] 刘崇岩 许文松 王坤[1,2] QI Minjie;ZHAO Guangming;LIU Chongyan;XU Wensong;WANG Kun(Key Laboratory of Safe and Effective Coal Mining,Ministry of Education,Anhui University of Science and Technology,Huainan 232001,China;State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学煤矿安全高效开采省部共建教育部重点实验室,安徽淮南232001 [2]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

出　　处：《煤炭学报》2025年第3期1541-1554,共14页Journal of China Coal Society

基　　金：安徽省高校优秀科研创新团队资助项目(2022AH010053);国家重点研发计划资助项目(2023YFC2907602);安徽省教育厅研究生学术创新资助项目(2022xscx080)。

摘　　要：为了研究应力补偿对单面卸荷砂岩力学特性与变形破坏特征的影响,采用真三轴扰动卸荷岩石测试系统对砂岩进行不同中间主应力单面卸荷试验和应力补偿路径下岩体破坏试验,基于Mg-C强度准则研究了2种应力路径对卸荷岩石强度参数的影响,分析了应力补偿后卸荷岩石的力学特性和变形特征。结果表明:在研究范围内,即使是在非常规真三轴状态下,中间主应力σ_(2 )的增大同样可以有效提高岩石的承载能力和稳定性,使岩石由塑性向脆性转化;2种应力路径下卸荷岩石的破坏模式存在差异,岩石的整体破坏模式随着σ_(2 )的梯次增大由张拉向张拉-剪切复合再到剪σ_(3)'切破坏发展,卸荷面附近的破碎区逐渐由深部向浅部转移,而随着卸荷面补偿应力的梯次增大,整体破坏模式由张拉-剪切复合破坏向剪切破坏转变,卸荷面附近的破碎区逐渐由浅部向深部转移;岩石在单面卸荷与应力补偿支护过程中,伴随着ε_(3)的扩容与压缩,ε_(2)基本上无明显变化,但是ε_(1)和ε_(v)发生2次明显的回弹变形,且ε_(1)和ε_(v)的变形与ε_(3)同步;应力补偿可以有效补偿卸荷引起的岩石应力损失,提高砂岩的黏聚力和破坏强度,使砂岩加卸载期间的补偿系数η(m1)、η(m^(3))、η(mv)逐渐增大,但对内摩擦角和η(m2)影响较小;在任意补偿应力条件下压裂系数ξ(m2)和ξ(m^(3))均为负值,岩石在σ_(2 )和σ3方向处于扩容状态,而ξ(m1)和ξ(mv)正好相反,在任意补偿应力条件下均为正值,岩石处于压缩状态。To study the effect of stress compensation on the mechanical properties and deformation damage characterist-ics of unloading sandstone,a true triaxial perturbation unloading rock testing system was used to carry out unloading ex-periments on sandstone with different intermediate principal stresses and rock damage experiments under stress compensa-tion paths,and the effects of the two stress paths on the strength parameters of unloading rock were investigated based on the Mg-C strength criterion,and the mechanical properties and deformation damage characteristics of unloading rock were analysed after the stress compensation.The results show that the increase of the intermediate principal stressσ_(2 )can effect-ively improve the bearing capacity and stability of the rock and transform the rock from plasticity to brittleness in a cer-tain range,even in the unconventional true triaxial state;There are differences in the damage patterns of unloading rocks under the two stress paths.The overall damage pattern of rocks develops from tension to tension-shear composite to shear damage with the gradient increase ofσ2,and the crushed area near the unloading surface gradually shifts from deep to shal-low,while the overall damage pattern changes from tension-shear composite to shear damage with the gradient increase ofσ_(3)'compensating stress at the unloading surface,and the crushed area near the unloading surface gradually shifts from shallow to deep.During the unloading and stress-compensated support of the rock on one side,accompanied by the expan-sion and compression ofε_(3),there is no significant change inε_(2),butε_(1) andε_(v) undergo two significant rebound deforma-tions,and the deformations ofε_(1) andε_(v) are synchronized with that ofσ3;Stress compensation can effectively compensate the rock stress loss caused by unloading,improve the cohesion and damage strength of sandstone,and gradually increase the compensation coefficients of sandstone during loading and unloading,η(m1),η(m^(3)),andη(mv),but hav

关 键 词：真三轴 单面卸荷 中间主应力 卸荷效应 应力补偿 

分 类 号：TD315[矿业工程—矿井建设]