Author:
Chen Yunteng,Geng Xiaoliang,Li Jianjun,Zhang Mingfeng,Zhu Chengfeng,Cai Mingcheng,Zhao Wenlin,Zhou Xin,Wang Tianzuo
Abstract
AbstractThe construction of super large section (SLS) shallow buried tunnels involves challenges related to their large span, high flat rate, and complex construction process. Selecting an appropriate excavation method is crucial for ensuring stability, controlling costs, and managing the construction timeline. This study focuses on the selection of excavation methods and the mechanical responses of SLS tunnels in different types of surrounding rock. The research is based on the Yangjiashan tunnel project in Zhejiang Province, China, which is a four-line highway tunnel with a span of 21.3 m. Three sequential excavation methods were proposed and simulated using the three-dimensional finite difference method: the “upper first and lower later” side drift (SD) method, the central diaphragm method, and the top heading and bench (HB) method. The mechanical response characteristics of tunnel construction under these methods were investigated, including rock deformation, rock pressure, and the internal forces acting on the primary support. By comparing the performance of the three construction methods in rock masses of Grades III to V, the study aimed to determine the optimal construction method for SLS tunnels considering factors such as safety, cost, and schedule. Field tests were conducted to evaluate the effectiveness of the optimized construction scheme. The results of the field monitoring indicated that the “upper first and lower later” SD method in Grade V rock mass and the HB method in Grade III to IV rock mass are feasible and cost-effective under certain conditions. The research findings provide valuable insights for the design and construction of SLS tunnels in complex conditions, serving as a reference for engineers and project managers.
Funder
Zhejiang Provincial Natural Science Foundation of China
Publisher
Springer Science and Business Media LLC
Reference23 articles.
1. Zhao, J., Tan, Z., Yu, R., Li, Z. & Wang, X. Mechanical responses of a shallow-buried super-large-section tunnel in weak surrounding rock: A case study in Guizhou. Tunn. Undergr. Space Technol. 131, 104850 (2023).
2. Chen, J. et al. Application of the upper-bench CD Method in super large-span and shallow tunnel: A case study of Letuan tunnel. Adv. Civ. Eng. 2020, e8826232 (2020).
3. Luo, Y. et al. Back-calculation method of rock mass pressure in a shallow-buried super large-span tunnel using upper-bench CD method. KSCE J. Civ. Eng. 26, 433–447 (2022).
4. Luo, Y., Chen, J., Shi, Z., Li, J. & Liu, W. Mechanical characteristics of primary support of large span loess highway tunnel: A case study in Shaanxi Province, Loess Plateau, NW China primary. Tunn. Undergr. Space Technol. 104, 103532 (2020).
5. Luo, Y. et al. Performance of super-large-span tunnel portal excavated by upper bench CD method based on field monitoring and numerical modeling. Adv. Civ. Eng. 2020, e8824618 (2020).