水资源与水工程学报2024，Vol.35Issue(3)：192-200,9.DOI:10.11705/j.issn.1672-643X.2024.03.22
强降雨影响下小净距隧道洞口段失稳机理及控制技术研究
Instability mechanism and deformation control techniques of the entrance sections of small net spacing tunnels under heavy rainfall
摘要
Abstract
Heavy rainfall can easily induce serious construction disasters in the entrance sections of doub-le-line tunnels with small net spacing.Based on on-site investigation and numerical simulation of a tunnel project in Guangxi,the instability characteristics and influencing factors of the surrounding rock at the en-trance sections of the small net spacing tunnels are analyzed,according to which,the deformation control techniques for the entrance section is proposed,and the reliability of these measures are verified by on-site testing.The research results indicate that the shallow and loose surrounding rock at the entrances of the tunnels,the short excavation distance between the left and right tunnels,and heavy rainfall are the main causes of the large deformation and collapse of the surrounding rock in the project;and the deforma-tion of the surrounding rock of the advance tunnel increases sharply with the decrease of the excavation displacement between the advance tunnel and the subsequent tunnel.Compared to the up and down step method,the seven step excavation with core soil method has significant advantages in controlling the de-formation of the surrounding rock by reducing the span and implementing timely support measures.In ad-dition,the deformation of the surrounding rock increases significantly after immersion and deterioration,and cannot be effectively controlled by increasing the excavation offset and changing the construction method.Based on these findings,a series of deformation control techniques are proposed,such as back-filling and sealing the surface collapse,increasing the excavation gap between the left and right tunnels,using the seven step excavation with core soil method for construction,shortening the excavation footage,and increasing the support strength,which are proven to produce excellent control effects.关键词
隧道工程/小净距隧道/洞口段/失稳机理/控制技术Key words
tunnel engineering/small net spacing tunnel/entrance section/instability mechanism/con-trol technique分类
交通工程引用本文复制引用
陈人豪,周祥,周东迎,唐宇辰,张玉伟..强降雨影响下小净距隧道洞口段失稳机理及控制技术研究[J].水资源与水工程学报,2024,35(3):192-200,9.基金项目
国家自然科学基金项目(52308374) （52308374）
交通运输部交通运输行业重点科技项目(2020-MS1-006) （2020-MS1-006）
