Analysis of the Stress Characteristics at the Dome Type Metro Tunnel Intersection
(1. Shandong Expressway Infrastructure Construction Co., Ltd., Jinan 250000; 2. Shandong University of Science and Technology, Qingdao 266590; 3. Shandong Provincial Transportation Planning and Design Institute Group Co., Ltd., Jinan 250101)
Abstract：
Taking a certain subway station as the research object, this study employs model testing, numerical simu? lation, and on-site monitoring to conduct a comparative analysis of the stress characteristics of surrounding rock and support structures under two tunnel structure forms: the unidirectional arch and the dome (bidirectional arch) at the intersection section of the station's air duct and the main tunnel. The research findings indicate that the dome shape is more conducive to tunnel stability, with surrounding rock settlement reduced by approximately 7% compared to the unidirectional arch, and a smaller disturbance range to the surrounding rock. The stress state of the surrounding rock at the inner corner exhibits a trend of "three-dimensional-two-dimensional-one-dimensional" changes, leading to the formation of cracks that require close attention. The maximum tensile stress in the sprayed concrete layer is0.11 MPa, located at the inner corner of the intersection and at the cross-section between the intersection section and main tunnel. During the excavation of the lower bench, the axial force of the hollow grouting anchor bolts in the air duct and the main tunnel decreases, while the prestressed anchor bolts in the intersection section are almost unaffected. Additionally, the stress on the steel arch in this section is significantly asymmetric, with localized tensile stress occurring in the steel arch near the main tunnel side. Based on these findings, a "support first, break later"construction method is proposed, which involves first erecting an inner steel arch before dismantling the original steel arch support. On-site monitoring shows that the maximum settlement of the dome-shaped tunnel is approximately 5.2 mm, and the stress on the support structure remains within a safe range, ensuring the overall stability of the tunnel.
WANG Mingfa1 LIU Guoshan1 YAN Jianquan2 MAN Xinjie1 LI Hongze2 ZHOU Yangyang1 LI Weiteng2GUO Guangming1 SHAO Xing3 JIANG Weiliang1
.Analysis of the Stress Characteristics at the Dome Type Metro Tunnel Intersection[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(1): 157-169
2025, Vol. 62 