Abstract
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 con-trolling 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 mechan-ical 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 com-pared 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 devel-oped. The mechanical properties and influence mechanism of confined concrete arches with different sec-tion 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 effectively controlled.
基金项目
国家自然科学基金(42277174)
国家自然科学基金(42077267)
国家自然科学基金()
国家自然科学基金(52074164)
Natural Science Foundation of Shandong Province,China(ZR2020JQ23)
Major Scientific and Technological Innovation Project of Shandong Province,China(2019SDZY04)
Project of Shandong Province Higher Educational Youth Innovation Science and Technology Program,China(2019KJG013)
opening project of State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology(KFJJ21-02Z)
NETL
NSTL
维普
万方数据