Long-Term Monitoring and Analysis of Lining Cracks in Operating Highway Tunnels
(1 School of Civil Engineering, Qingdao University of Technology, Qingdao 266033; 2 Key Laboratory for Urban UndergroundEngineering of Ministry of Education, Beijing Jiaotong University, Beijing 100044)
Abstract：
Cracks are generally distributed in the linings of operating highway tunnels, for which stability directly
affects the operational safety of the tunnels. Monitoring tools are an intuitive and effective method for analyzing and predicting the development of cracks. However, because there is a lack of monitoring documentation regarding lining cracks, the following study was carried out based on a second-class highway tunnel: the lining crack distribution laws were analyzed from 3 aspects—crack types, location and surrounding rock grades of cracks and geometric features of cracks—and 12 selected typical lining cracks have been monitored for 2 years using fiber grating sensors.The monitoring results show that the lining crack development laws can be divided into 4 types: stable, periodically changing, increasing and closed. Most of the cracks are correspondingly stable and controllable based on the monitoring data of the crack′s geometric features, which slightly affects the stability of tunnel structure. After systematic
analysis of the causes of tunnel lining cracks from the aspects of survey and design, construction and operation management, countermeasures for the tunnel lining cracks are proposed. The treatment principle of“monitoring first, followed by classification and then selection of treatment measures”is suggested to treat the lining cracks. The results provide a useful reference for the assessment and treatment of cracks in similar tunnels both at home and abroad.
2017, Vol. 54 