Mechanical properties and influence mechanism of confined concrete arches in high-stress tunnels  

作　　者：Bei Jiang Zhongxin Xin Xiufeng Zhang Yusong Deng Mingzi Wang Shidong Li Wentao Ren 

机构地区：[1]State Key Laboratory for Geo-mechanics and Deep Underground Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China [2]State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China [3]Research Center of Geotechnical and Structural Engineering,Shandong University,Jinan 250061,China [4]Shandong Energy Group Co.,Ltd.,Jinan 250014,China

出　　处：《International Journal of Mining Science and Technology》2023年第7期829-841,共13页矿业科学技术学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 42277174, 42077267, and 52074164);the Natural Science Foundation of Shandong Province, China (No. ZR2020JQ23);Major Scientific and Technological Innovation Project of Shandong Province, China (No. 2019SDZY04);the Project of Shandong Province Higher Educational Youth Innovation Science and Technology Program, China (No. 2019KJG013);the opening project of State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology (No. KFJJ21-02Z)。

摘　　要：Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,which makes it difficult to meet the requirements of ground control under complex conditions. As a new support form with high strength and rigidity, the confined concrete arch plays an important role in controlling the rock deformation under complex conditions. The section shape of the tunnel has an important impact on the mechanical properties and design of the support system. However, studies on the mechanical properties and influence mechanism of the new confined concrete arch are rarely reported. To this end, the mechanical properties of traditional U-shaped steel and new confined concrete arches are compared and comparative tests on arches of circular and straight-leg semicircular shapes in deep tunnels are conducted. A large mechanical testing system for underground engineering support structure is developed. The mechanical properties and influence mechanism of confined concrete arches with different section shapes under different loading modes and cross-section parameters are systematically studied. Test results show that the bearing capacity of the confined concrete arch is 2.10 times that of the U-shaped steel arch, and the bearing capacity of the circular confined concrete arch is 2.27 times that of the straight-leg semicircular arch. Among the various influencing factors and their engineering parameters,the lateral stress coefficient has the greatest impact on the bearing capacity of the confined concrete arch,followed by the steel pipe wall thickness, steel strength, and core concrete strength. Subsequently, the economic index of bearing capacity and cost is established, and the optimization design method for the confined concrete arch is proposed. Finally, this design method is applied to a high-stress tunnel under complex conditions, and the deformation of the surrounding rock is effectivel

关 键 词：High-stress tunnel Confined concrete arch Section shape Mechanical properties Design method 

分 类 号：U451[建筑科学—桥梁与隧道工程]