Qingsong Zhang

Development of a new type of steel structure rack apparatus for 3D geomechanical model tests and structural integrity assessment

Because of the sustainable development of national economy and the implementations of western development strategies in China, our country will be faced with tremendous geotechnical engineering projects like the Three Gorges Project, South-to-North Water Transfer Project, Beijing-to-Shanghai High-Speed Railway Project etc. In the meantime, these projects will be confronted with a massive number of excavations of rock and soil, which involve problems of failure, deformation and reinforcement in rock mass medium. One method of solving the problems is to use theoretical analysis and computational simulation, and the other is to use geomechanical model tests, which can also be called physical model test. This paper discusses a new type of steel structure rack apparatus used in 3D geomechanical model tests on the basis of domestic studies on this kind of structure. This structure can physically simulate the most complex and difficult projects in civil engineering. This new structure is composed of a rack body, rack bottom, longitudinal tensile rods, high-strength screw bolts etc. The rack body of the apparatus consists of various boxlike cast-steel structure members connected by high-strength screw bolts, and the rack bottom plate consists of shaped steel plates with screw bolt grooves. After finishing designing the rack apparatus, a structural integrity assessment is necessary. We used the universal FEM (Finite Element Method) to study it. This structure has been successfully used in a geomechanical model test of a branching-out tunnel. The results indicate that it possesses remarkable technical superiority such as original structure, high stiffness, good stability, flexible assembly and free regulation for its size.