Research on Optimization of Construction Methods for Ultra-large
Cross-section Tunnels: A Case Study of the Lihuashan Tunnel on the Tianfu
New Area-Qionglai Expressway
(1. Pavement Engineering Branch of Sichuan Communications Construction Group Co., Ltd., Chengdu 610047;
2. School of Architecture and Civil Engineering, Xihua University, Chengdu 610039; 3. Sichuan Tibetan Area Expressway Co., Ltd.,
Chengdu 610047; 4. Sichuan Communications Construction Group Co., Ltd., Chengdu 610047; 5. Sichuan Dujin Mountain Rail Transit
Co., Ltd., Wenchuan 623006; 6. Sichuan Provincial Transport Department Highway Planning, Survey, Design and Research Institute,Chengdu 610041)
Abstract：
With the rapid development of infrastructure projects in western China, the demand for expressway tunnelling has been increasing. Among them, ultra-large cross-section tunnels present considerable challenges for construction due to their low flatness ratio, large span, and complex excavation procedures. This study takes the Lihuashan Tunnel, a key control project on the Tianfu New Area-Qionglai Expressway, as the research object, and systematically investigates construction methods suitable for ultra-large cross-section tunnels. Numerical simulations were conducted to compare the differences between the double side drift method and the six-step steel frame rock wall method in terms of surrounding rock stability and structural stress characteristics, thereby verifying the safety
and reliability of the latter. Further optimization of construction sequences for different steel frame rock wall method construction schemes was carried out to determine the most effective sequence. Based on field monitoring data, the deformation characteristics of surrounding rock and the stress characteristics of primary support structures during actual construction were analyzed, further validating the engineering applicability of the six-step steel frame rock wall method. The results indicate that this method can ensure construction safety while significantly improving progress.
LUO Long1 ZHU Kaicheng2 HAN Yuxuan3 CAI Dong4 LIU Zheqi5 WANG Jun6
.Research on Optimization of Construction Methods for Ultra-large
Cross-section Tunnels: A Case Study of the Lihuashan Tunnel on the Tianfu
New Area-Qionglai Expressway[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(4): 273-282
2025, Vol. 62 