不同温度养护后胶结充填体三轴卸围压力学特性试验研究  

Experimental study on mechanical characteristics of cemented backfill under triaxial unloading confining pressure after cured at different temperatures

作　　者：刘炜震 郭忠平[1] 黄万朋[1,2] 牛世伟 侯吉峰 LIU Weizhen;GUO Zhongping;HUANG Wanpeng;NIU Shiwei;HOU Jifeng(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;State Key Laboratory of Coal Mining and Clean Utilization,China Coal Research Institute,Beijing 100013,China;College of Coal Engineering,Shanxi Datong University,Datong,Shanxi 037009,China)

机构地区：[1]山东科技大学能源与矿业工程学院,山东青岛266590 [2]煤炭科学研究总院煤炭资源高效开采与洁净利用国家重点实验室,北京100013 [3]山西大同大学煤炭工程学院,山西大同037009

出　　处：《岩石力学与工程学报》2022年第11期2268-2282,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点研发计划资助项目(2018YFC0604706);国家自然科学基金资助项目(51774195);煤炭科学研究总院煤炭资源高效开采与洁净利用国家重点实验室开放基金资助项目(2021-KFYB-020)。

摘　　要：为研究胶结充填体在煤矿深部的高地温环境下发生卸荷的力学特性,采用RTX–4000型岩石动态三轴仪,对不同温度(20℃,35℃和50℃)养护后的胶结充填体进行不同初始卸荷围压下的常规三轴卸围压试验,得到胶结充填体三轴卸荷全过程的偏应力–应变曲线,分析其变形、破坏特征及强度准则。研究结果表明:50℃养护后的胶结充填体内部产生的有害热应力易使胶结充填体卸荷的应力–应变曲线在峰后阶段出现微破裂现象,进而使得变形模量在随围压卸载的过程中也出现突降和逆向增长。胶结充填体卸荷破坏形式主要为局部张拉裂纹、剪切裂纹以及由热损伤和力学损伤共同造成的错位裂纹。Mogi-Coulomb强度准则能更好地表征胶结充填体在增轴压卸围压条件下的卸荷破坏强度特征;随养护温度的升高,胶结充填体的黏聚力先减小后增大,内摩擦角先增大后减小,黏聚力的变化同卸荷峰值强度的变化规律一致,黏聚力越大,卸荷峰值强度越高,表明黏聚力为影响胶结充填体卸荷峰值强度的主要因素。In order to study the unloading mechanical characteristics of cemented backfill in the high geothermal environment of deep coal mine,RTX–4000 rock dynamic triaxial apparatus was used to carry out the conventional triaxial unloading confining pressure test under different initial unloading confining pressures on cemented backfill after cured at different temperatures(20℃,35℃and 50℃).The deviatoric stress-strain curve of cemented backfill during the whole triaxial unloading process was obtained,and its deformation,failure characteristics and strength criterion were analyzed.The results show that the harmful thermal stress inside cemented backfill after cured at 50℃is easy to cause the stress-strain curve of cemented backfill under unloading to appear micro-rupture phenomenon in the post-peak stage,and then makes the deformation modulus drop suddenly and increase reversely in the process of unloading confining pressure.The unloading failure forms of cemented backfill are mainly local tension cracks,shear cracks and dislocation cracks,in which the dislocation cracks are caused by thermal damage and mechanical damage.Mogi-Coulomb strength criterion can better characterize the unloading failure strength characteristics of cemented backfill under the condition of increasing axial pressure and unloading confining pressure.With the increase of curing temperature,the cohesive force of cemented backfill decreases first and then increases,and the internal friction angle increases first and then decreases.The change of cohesive force is consistent with the change law of unloading peak strength.The greater the cohesive force,the higher the unloading peak strength,indicating that cohesive force is the main factor affecting the unloading peak strength of cemented backfill.

关 键 词：采矿工程 养护温度 胶结充填体 三轴卸围压 变形 强度准则 

分 类 号：TD32[矿业工程—矿井建设]