基于应力解除法的九岭山隧道洞壁二次应力场分布规律研究  

Stress relief method-based study on distribution law of secondary stress field in tunnel wall of Jiuling Mountain Tunnel

作　　者：马振旺 汪波[1] 王志伟[1] 谭力豪 全晓娟[1] MA Zhenwang;Wang Bo;WANG Zhiwei;TAN Lihao;QUAN Xiaojuan(Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University,Chengdu 610031, Sihchuan, China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031

出　　处：《水利水电技术》2019年第2期184-190,共7页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金项目(51878571;51578456);广东省交通科技项目(2016-02-014)

摘　　要：为了解九岭山隧道开挖后洞壁二次应力场分布规律及其与岩爆发生状况之间的关联性,采用应力解除法沿九岭山隧道全线选取岩体完整,受开挖扰动小的部位进行了洞壁二次应力的实测,并结合现场岩爆实际发生情况,对洞壁二次应力场的分布规律进行综合对比分析,并结合应力判据对岩爆进行了二次准确预测。研究结果表明:洞壁二次应力值与隧道埋深呈现近似线性关系,二次应力量值呈现σ_1>σ_θ>σ_x>σ_3>τ_(xy)的特征;洞壁切向应力σ_θ最大为63.944 MPa,最大主应力σ_1最大值为77.17 MPa,二者量值相差7.5%,对岩爆的发生均起主导作用;洞室开挖后的洞壁切向应力σ_θ与埋深的相关系数为0.933 23,相比最大主应力σ_1与埋深的相关系数0.897 22,σ_θ与埋深的相关性更好;隧道开挖后,切向应力σ_θ在30～50 MPa范围内时可初步判定将可能发生微岩爆,σ_θ大于50 MPa时可初步判定将可能发生中等岩爆;以此为基础,再结合应力判据可对岩爆发生等级做出准确预测。研究成果为高地应力硬岩隧道岩爆预测提供新的思路。In order to understand the distribution law of the secondary stress field in the tunnel wall after the excavation of Jiuling Mountain Tunnel and its correlation with the occurrence of rock burst, the actual measurement of the secondary stress in the tunnel wall is carried out through adopting the stress relief method to select the integral rock mass and the positions with less disturbance from excavation along the whole line of the tunnel, and then a comprehensivecontrastive analysis is made on the distribution law of the secondary stress field in the tunnel wall in combination with actual occurrence of the in situ rock burst, while the secondary accurate prediction is made on the rockburst occurred therein with the relevant stress criterion. The study result shows that an approximate linear relationship is there between the value of the secondary stress in the tunnel wall and the buried depth of the tunnel, for which the magnitude of the secondary stress exhibits the characteristics of σ1>σθ>σx>σ3>τxy.The maximum tangential stress σθ of the tunnel wall is 63.944 MPa and the maximum value of the maximum principal stressσ1 is 77.17 MPa;for which a difference of 7.5% is between both of the magnitudes of them, thus both of them play the leading roles for the occurrence of rockburst. The coefficient of the correlation between the tangential stressσθof the tunnel wall after the excavation and the buried depth is 0.933 23, which is much better if coMPared with the correlative coefficient of 0.897 22 between the maximum principal stress σ1 and the buried depth. After the excavation of the tunnel, when the tangential stress σθ is within the range of 30~50 MPa, it is can be preliminarily determined that a micro-rockburst is possibly to occur, while the possible occurrence of a moderate rockburst can be preliminarily determined when σθ is larger than 50 MPa. On the basis of this and in combination with the relevant stress criterion, an accurate prediction of the occurrence grade of rockburst can be made. Th

关 键 词：九岭山隧道 二次应力场 应力解除法 岩爆 隧洞工程建设 地下洞室开挖 岩石单轴抗压强度 

分 类 号：U456[建筑科学—桥梁与隧道工程]