| The STS (Steel Tube Slab) method is a new metro subsurface excavation method of subway construction. This method includes the construction technologies of tunnel excavation below the super highway in Korea and the domestic PBA method. The However, the welded flange slab in new method which is different from the Korean makes the mechanical property change a lot. Because it is the first time to use the STS method in China, research about the mechanical property and the design theory should be done sooner to raise the usability.The paper consists two parts:numerical research and theological analysis. First, the stress distribution of the STS structure under transverse bending moment has been obtained from the ANSYS numerical analysis. The transverse tensile strain of steel pipe has been confirmed according to the stress characteristic. Second, the steel tube deformation formula has been acquired using the structural mechanical method. Combining the deformation formula with the rigidity calculation formula in Code for Design of Concrete Structure, the calculation of transverse rigidity for STS structure has been obtained.The numerical analysis computation indicates that the welded flange slab can increase the rigidity apparently, whereas stress concentration occurs in the welding position between the steel pipe and the flange. Increasing the thickness of the steel pipe and the flange slab can raise the rigidity of the STS structure. Raising the concrete strength can also increase the rigidity. Comparing the result by rigidity calculation and the numerical data, the analysis indicates that the two coincide when the load is large enough when the concrete cracked, whereas larger deviation occurs when the structure is under lower load.According to the comparison of the numerical analysis and the theological calculation result, the calculation method in this paper can be used in the future and it can be the theological evidence for congeneric structure designing. |
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