基于位移反分析方法的隧道衬砌最早施作时机研究  

Earliest Lining Construction Time Based on Displacement Back Analysis Method

作　　者：孙明社 吴旭 宋克志[1] 郭彩霞 武光明 SUN Mingshe;WU Xu;SONG Kezhi;GUO Caixia;WU Guangming(School of Civil Engineering,Ludong University,Yantai 264025,Shandong,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;Key Laboratory of Urban Security and Disaster Engineering,the Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]鲁东大学土木工程学院,山东烟台264025 [2]北京交通大学土木建筑工程学院,北京100044 [3]北京工业大学城市与工程安全减灾省部共建教育部重点实验室,北京100124

出　　处：《隧道建设（中英文）》2023年第12期2046-2055,共10页Tunnel Construction

基　　金：国家自然科学基金项目(51978322,51478213);鲁东大学科研启动基金资助项目(20210117)。

摘　　要：衬砌的施作时机关系到隧道工程的施工安全和长期稳定性,目前大多通过施工监控量测的极限位移和变形速率来判断围岩的稳定性,从而确定衬砌的施作时机,但这种方式缺乏合理的理论依据。为了研究衬砌的合理施作时机,结合某新建铁路隧道工程,考虑衬砌对围岩和初期支护的约束作用,提出一种基于位移反分析法的衬砌最早施作时机确定方法。首先,基于初期支护的变形监测数据进行变形曲线拟合,确定初期支护的剩余变形;其次,利用位移反分析法,由初期支护的剩余变形反分析对应的围岩应力场,进而将该围岩应力场作用在初期支护和衬砌上进行正分析求解衬砌应力;最后,以容许拉应力和抗剪安全系数作为判定指标综合评价衬砌的安全性,确定隧道衬砌最早施作时机。研究结果表明:1)依托工程初期支护的剩余变形随着时间的增长逐渐减小,初期支护闭合10 d内,其剩余变形递减速率较大而后逐渐减小;2)该工程可施作衬砌的最早时间为初期支护闭合后39 d;3)依据衬砌的实际施作时间(初期支护闭合后100 d),衬砌截面内力的监测结果与反分析计算结果基本一致;4)通过初期支护的剩余变形反分析对应围岩应力场,进而正分析衬砌应力,确定衬砌可施作时机的方法是可行的。The safety and long-term stability of tunnel engineering rely heavily on the lining construction time,primarily determined through in-situ monitoring of the stability of the surrounding rock.However,this approach needs a rational theoretical basis.To address this issue,a method that uses displacement back analysis technology is proposed for a new railway tunnel project.This method considers the constraint effect of the lining on the surrounding rock and primary support.It involves fitting a deformation curve based on primary support monitoring data to determine the residual deformation.The corresponding surrounding rock stress field is derived using displacement back analysis.This stress field is then applied to the primary support and lining via the finite element method to obtain the lining stress.Evaluation criteria,such as allowable tensile stress and shear safety factor,comprehensively assess lining safety and determine its earliest construction time.The results show that the residual deformation of the primary support decreases gradually over time,with a substantial deceleration rate within the first 10 days after primary support completion.The earliest lining construction time for a specific tunnel case is 39 days after primary support completion.At the in-situ lining construction time(100 days after primary support completion),the monitoring results of the lining internal force align well with the back analysis results,confirming the feasibility of the proposed method.

关 键 词：隧道 衬砌最早施作时机 反分析 剩余变形 容许应力 抗剪安全系数 

分 类 号：U451[建筑科学—桥梁与隧道工程]