Experimental study on mechanical behavior of nonsymmetric multi-arch tunnel in sand-cobble ground
He Jun1,2 Zhang Chengping1,2 Yang Gongbiao1,2 Wang Mengshu1,2
1. Key Lab of Urban Underground Engineering of the Ministry of Education, Beijing Jiaotong University, Beijing 100044, China
2. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
Abstract：In this work, the independently designed large-scale plane model test bench and the similarity model materials according to the features of sand-cobble ground were employed to study the mechanical characteristics of nonsymmetric multi-arch tunnels, with special emphasis on the characteristics of stress field, the distribution of internal force, the crack development of tunnel and the structural failure process. The test results indicate that: the pressure applied on the outer surface of lining of the large-diameter tunnel was remarkably larger than that of the small-diameter tunnel, but in the both tunnels the distributions of outer surface pressures were similar, that is, the maximum pressure appeared at the tunnel crown, the second one was seen at the inside of tunnel spandrel, and the minimum one was observed at the tunnel haunch. The nonsymmetric distributions of stresses at left and right tunnels lead to an obvious eccentric compression in the middle wall. The grouting reinforcement ring can effectively reduce the outer surface pressure on lining and improve the stress condition and the stability of the structure. Initially, the internal force of the structure increased linearly with the increase of load, and then the internal force redistributed after the first crack appeared but the structure still had a certain bearing capacity. The longitudinal cracks appeared firstly at the tunnel arch foot near the middle wall, then the number and the width of cracks increased with the increase of load, while the cracks mainly distributed at the side of tunnel lining near the middle wall.
何珺 张成平 杨公标 王梦恕. 砂卵石地层非对称连拱隧道结构受力模型试验研究[J]. 土木工程学报, 2017, 50(4): 116-124.
He Jun Zhang Chengping Yang Gongbiao Wang Mengshu. Experimental study on mechanical behavior of nonsymmetric multi-arch tunnel in sand-cobble ground. 土木工程学报, 2017, 50(4): 116-124.
