围岩应力梯度对应变型岩爆特征荷载影响模型试验研究  

Experimental Study on Model of Influence of Stress Gradient of Surrounding Rock on Characteristic Load of Strain Rockburst

作　　者：张航 夏元友[1] 刘夕奇 祝文化[1] 吝曼卿[2] ZHANG Hang;XIA Yuan-you;LIU Xi-qi;ZHU Wen-hua;LIN Man-qing(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan Hubei 430070,China;School of Resources and Safety Engineering,Wuhan Institute of Technology,Wuhan Hubei 430062,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070 [2]武汉工程大学资源与安全工程学院,湖北武汉430062

出　　处：《公路交通科技》2021年第1期104-111,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(42077228,51504167);中央高校基本科研业务费资助项目(2017-YB-022);高等学校博士学科点专项科研基金项目(520110143110017)。

摘　　要：应变型岩爆是在深地下开挖引起围岩应力集中后受梯度应力作用下产生的。为探明围岩应力梯度对应变型岩爆围岩破坏及特征荷载的影响,采用自主研发的真三轴气液复合加卸载岩爆模拟试验装置,在相同模型材料、围压与单面卸载条件下,进行了4种竖向梯度应力加载的岩爆模型试验。试验采用类岩石材料的大尺寸(1000 mm×600 mm×400 mm)试件实现竖向梯度应力加载,模型材料选取具有强岩爆倾向的水膏比为0.7的石膏材料。基于岩爆模型试验的宏观破坏现象观察及加卸载过程的声发射能量与累计能量曲线,分析了竖向加载应力梯度系数对试件岩爆破坏特征的影响规律。基于试验过程的加载应力及声发射振铃总计数曲线的阶段性变化分析,获得了4种不同竖向梯度应力加载条件下试件的峰值荷载、起裂荷载与损伤荷载。结果表明:随着竖向加载应力梯度系数的增大,岩爆碎屑由大块板状为主逐渐过渡到以小块片状、块状与粉末状为主,岩爆碎屑的弹射最大距离逐步增大,岩爆的动力破坏现象越来越来越明显;试件在破坏过程中释放的累计能量逐渐减小,能量释放越来越趋于临近岩爆前集中释放;试件的起裂荷载趋向于增大,损伤荷载则变化不大,峰值荷载减小。Strain rockburst is generated under the action of gradient stress after the stress concentration of surrounding rock caused by deep underground excavation.In order to find out the influence of stress gradient of surrounding rock on failure and characteristic load of strain rockburst surrounding rock,the rockburst model test under 4 vertical gradient stress loadings is carried out by using the self-developed true triaxial gas-liquid composite loading and unloading rockburst simulation test device under the conditions of same model material,confining pressure and one-side unloading.The test uses large-size(1000 mm×600 mm×400 mm)specimens of rock-like material to achieve vertical gradient stress loading.The model material is the gypsum material with a strong rockburst tendency and a water-gypsum ratio of 0.7.Based on the observation of the macroscopic failure phenomenon of the rockburst model test and the acoustic emission energy and cumulative energy curves of the loading and unloading process,the influence rule of the vertical loading stress gradient coefficient on the rockburst failure characteristics of the specimens is analyzed.The peak load,crack initiation load and damage load of the specimens under 4 vertical gradient stress loading conditions are obtained based on the analysis of the stage changes of loading stress during the test and acoustic emission ringing total counting curve during the test process.The result shows that(1)with the increase of stress gradient coefficient of vertical loading,the rockburst debris gradually transitioned from large plate-like shape to small sheet,block and powder shapes,the maximum ejection distance of rockburst debris gradually increased,and the dynamic failure phenomenon of rockburst became more obvious;(2)the cumulative energy released by the specimens during the loading process gradually decreased,and the energy release became more and more concentrated near rockburst;(3)the crack initiation loads of specimens tended to increase,the damage loads changes little,and th

关 键 词：隧道工程 应变型岩爆 试验研究 应力梯度系数 特征荷载 声发射 

分 类 号：U452.26[建筑科学—桥梁与隧道工程] TU431[交通运输工程—道路与铁道工程]