Study on the Structural Response of the Main Tunnel with Deep Cross Passages Built by the Mechanical Method
(1. Collaborative Innovation Center of Coastal Urban Rail Transit，Ningbo University，Ningbo 315201; 2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092)
Abstract：
The mechanical method for cross passages provides a new idea for the rapid connection of various under? ground structures. It is a construction method with strong feasibility and application prospect. In order to study the applicability of this construction method under deep buried conditions, a full-scale test on the segmental tunnel rings with opening using mechanical method under deep buried conditions has been carried out. The response characteristics of segments and joints are obtained, and the force transmission characteristics and failure process of tunnel structure under deep buried conditions are clarified. The following main conclusions are as followed: (1) Under the condition of deep burial, the change of the structural response in the tunnel opening ring is mainly concentrated in the dismantling condition, and the main structural response is concentrated on the cantilever end of the opening ring and top of the tunnel; (2) The changes of the inter-ring structural response of tunnel openings under buried conditions are mainly concentrated in the cutting and bracing conditions. Under the cutting condition, the inter-ring structural response is a local structural response; in the load-holding stage of the dismantling condition, the interring structural response extends to the entire ring; (3) The failure process of the main tunnel structure under deep burial conditions can be divided into two stages. Before the brace is removed and after the steel sleeve is cut off, the cantilever effect occurs, and the bearing capacity between the fully-opened ring and the half-opened ring reaches the limit. In the load-holding stage of the dismantling condition, the fully-opened ring is damaged, and the load is transferred to the adjacent rings in turn through the transmission between rings; (4) In the final state, the fullyopened ring reaches the bearing capacity limit while the remaining rings are still in the elastic stage. The structure in the actual project is safer than that in the test, but special design and construction should be carried out on the opening ring and the ring joints near the opening position.
ZHU Yaohong1 GAO Yimin2 LIU Xian2
.Study on the Structural Response of the Main Tunnel with Deep Cross Passages Built by the Mechanical Method[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(5): 144-154
2022, Vol. 59 