考虑主应力轴偏转的深埋盾构隧道开挖面主动极限支护压力计算方法  

A calculation method of active limit support pressure for deep shield tunnels considering principal stress axis rotation

作　　者：张孟喜[1] 戴治恒 张晓清 吴惠明 付钊[1] ZHANG Mengxi;DAI Zhiheng;ZHANG Xiaoqing;WU Huiming;FU Zhao(School of Mechanism and Engineering Science,Shanghai University,Shanghai 200444,China;Shanghai Tunnel Engineering Co.,Ltd.,Shanghai 200032,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]上海隧道工程有限公司,上海200032

出　　处：《岩石力学与工程学报》2021年第11期2366-2376,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52078286);上海市市级科技重大专项资助课题(2017SHZDZX02);上海隧道工程股份有限公司“北横通道”项目科研课题(2017–SK–2)。

摘　　要：盾构隧道开挖通常引起土体的非均匀沉降,呈现出越远离开挖面沉降越小的规律。非均匀沉降引起土体之间产生剪切应力,使得土体主应力轴发生偏转,土体应力状态也随之发生变化。基于前期室内砂土模型试验结果,采用理论推导和数值模拟的方法,研究主应力轴偏转对深埋隧道主动极限支护压力的影响。首先采用理论推导的方法,分析开挖面局部失稳和整体失稳时,土拱效应对极限支护压力的影响;然后结合传统太沙基松动土压力公式,推导了开挖面局部失稳极限支护压力的一般性通解;进一步考虑开挖面变形过程中前方土体主应力旋转,推导深埋盾构隧道开挖面整体失稳主动极限支护压力计算公式。随着埋深越大,极限支护压力逐渐增大;当埋深比大于3时,极限支护压力趋于平缓。开挖面极限支护压力随着内摩擦角的增大而减小,相反,随着黏聚力的增大而增大。楔形体倾角和棱柱体高度均对极限支护压力有显著影响。The excavation of shield tunnels usually causes non-uniform settlement,which shows a general law that the farther away from the excavation surface,the smaller the settlement. The non-uniform settlement causes shear stress in the soil,rotates the principal stress axis of the soil and hence,changes the stress state of the soil. Based on the results of early indoor sand soil model tests,theoretical derivation and numerical simulation methods were adopted to study the influence of principal stress axis rotation on the active limit support pressure for deep shield tunnels. Firstly,the influence of the soil arching effect on the limit support pressure was analytically discussed when the tunnel face was local instability and global instability. Then,combined with the traditional Terzaghi loose earth pressure formula,a general solution of the local instability limit support pressure was derived. Further,considering the principal stress rotation of the front soil during the deformation of the tunnel face,a formula of the active limit support pressure for the global instability of the deep-buried shield tunnel face was derived. The limit support pressure gradually increases with increasing the burial depth and tends to be constant while the burial depth ratio is greater than 3. The limit support pressure of the tunnel face decreases with increasing the internal friction angle,while increases with increasing the cohesion. Both the inclination angle of the wedge and the height of the prism have a significant impact on the limit support pressure.

关 键 词：隧道工程 理论解析 深埋 盾构隧道 主应力偏转 极限支护压力 

分 类 号：U45[建筑科学—桥梁与隧道工程]