Experimental study on the ultimate shear bearing capacity of segment joint in shield tunnel with large quasi-rectangular cross-section
Gong Yifan1,2 Ding Wenqi1,2 Gong Chenjie1,2 Jiang Hong3
1. College of Civil Engineering, Tongji University, Shanghai 200092, China;
2. Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China;
3. Shanghai Urban Construction Design & Research Institute (Group) Co., Ltd., Shanghai 200011, China
Abstract：The quasi-rectangular shield tunnel has wide application prospects in the high-density area of city, due to its advantages of large section utilization, shallow overburden and low construction cost. Compared with the widely used circular tunnels, quasi-rectangular tunnels are prone to produce large shear loads at shoulder joint structure due to their poor arching effect, so it is necessary to study the shear behavior of the joints. In this work, a full-scale test was conducted to investigate the ultimate shear capacity of the segment joint in a shield tunnel with large quasi-rectangular cross-section. By summarizing the macro-failure state, the global mechanical responses such as shear axis ratio (shear force divided by axial force)-dislocation relationships as well as the local mechanical responses such as shear axis ratio-bolt strain curves and shear axis ratio-concrete surface strain were achieved. Furthermore, digital image correlation (DIC) analyses were then introduced to record the entire cracking and failure process of the joint structure. The propagation rule of shear cracks was analyzed, and then
the shear capacity of the joint was evaluated. Based on the test results, the relationship curve between the segment dislocation and the shear axis ratio appears to be four stages: the friction resistant stage (shear axis ratio is less than 0.4), the gap closure stage (shear axis ratio is in the range of 0.4~0.75), shear hardening stage (shear axis ratio is in the range of 0.75~2.76) and the yield failure stage (shear axis ratio is larger than 2.76). Test results indicate that under the shear loading, the yield shear axis ratio of the joint used in the present shield tunnel with large cross-section is 2.76, implying its good shear bearing capacity. The results in this study can be referred theoretically and technically by similar quasi-rectangular shield tunnel projects.
巩一凡 丁文其 龚琛杰 姜 弘. 大断面类矩形盾构隧道管片接头极限抗剪切#br#
承载力试验研究[J]. 土木工程学报, 2019, 52(11): 120-128.
Gong Yifan Ding Wenqi Gong Chenjie Jiang Hong. Experimental study on the ultimate shear bearing capacity of segment joint in shield tunnel with large quasi-rectangular cross-section. 土木工程学报, 2019, 52(11): 120-128.
