Work

Characteristics and control techniques of soft rock tunnel lining cracks in high geo-stress environments: Case study of Wushaoling tunnel group

Year: 2024

Type: article

Abstract: A high geo-stress environment severely damages tunnel structures owing to the large deformation of the surrounding rock, thereby threatening their safety. In this study, the Wushaoling highway tunnel group, which passes through a high geo-stress environment, is investigated as a case study. The spatial distribution of different types of tunnel cracks is analyzed based on the site observations. The lining crack variations, such as circumferential and longitudinal cracks, with the factors including grade of the surrounding rock, location of buried depth, and design type of the tunnel lining are investigated. Various structural reinforcement technologies are presented based on the damage degrees of the tunnel linings. Several finite element models of supporting structures are established to reveal the mechanism of tunnel crack control technology. The results show that longitudinal and circumferential cracks are the main characteristics of tunnel lining damage in high geo-stress environments, accounting for approximately 29.4 and 53.2% of the total cracks, respectively. SIVb-, SVc-, and SVd-type linings show numerous longitudinal cracks per kilometer. The longitudinal cracks appear primarily on the tunnel crown and hance. In terms of the lining support types in Grade V surrounding rocks, the number of longitudinal cracks per kilometer increases with the lining grade. The number of tunnel cracks per kilometer tends to increase with the buried depth. Four tunnel structure reinforcement treatment measurements for lining cracks in high geo-stress condition were innovatively proposed, which were proved effective in deformation controlling and strengthening the tunnel lining using numerical investigation. The key contribution of this research is to reveal the characteristics and evolution mechanism of tunnel lining cracks in high geo-stress condition, and provide effective treatments for the tunnel lining cracks. In addition, the findings from the study on the tunnel lining cracks also provide industry practitioners with a comprehensive guide regarding the characteristics and control techniques of the tunnel lining cracks, which can serve as a steppingstone to facilitate the construction technology development of the transportation industry.

Source: Open Geosciences

DOI: 10.1515/geo-2022-0743