Papers by Keyword: Temporary Support

Abstract: Basedon the present situation of the domestic comprehensive tunneling temporary supporting technology, machine support and temporary support device is researched. This paper is on the basis of the previous design simple optimization.The design enhances temporary support level and improves its ability to support for a long time, in some extent, increases the strength of roof support. The optimization is described in detail.By adding a hydraulic cylinder,it can make each lever own supporting ability and ensure support stability. Organizationstructure and three dimensional graphics are drawn in the paper.The force analysis is carried. Finally appropriate position is determined.

Abstract: The calculation method for load of multi-arch and extra large cross section tunnels (MELCST) is a new method accounting for the influences caused by the multi-step construction procedure and temporary support on tunnels. The paper analyses the application of the method in the double-side drift construction method, and gives the distribution mode and the value of loose loads in various construction sequence, example analysis is also given through Luohanshan tunnel.

Abstract: Tests on two simple supported steel bar truss and concrete superimposed floor slabs have been carried out to study their mechanic behavior and bearing capacities. The one is prefabricated steel truss concrete slab without temporary support in the mid-span to simulate its mechanic status in construction stage, the other is superimposed board (prefabricated + post-cast layer) in use phase. Test results show that the deformation of the prefabricated steel truss concrete slab in construction stage meets the requirement of the Code, and the slab is mainly controlled by deflection instead of cracks; Performance of superimposed board is excellent in use stage; and the steel bar is elastic in both stages during the tests.

Abstract: During construction, the spatial shell structure is the variable constraint structure system. In order to guarantee the construction quality and safety, its addition or disassembly scheme of temporary support must be optimized design. Based on variable constraint structure analysis method, the paper simulated and analyzed possible multiple variable constraint scheme during the long-span space reticulated shell structural construction, and put forward the principle and method abide by addition and disassembly design of temporary support. For other variable constraint structures similar to the spatial shells, the principle and method proposed has a very great reference value.

Abstract: By the study of construction of casting box girder of Songpu Bridge in Harbin, and the actual site geology, hydrology and the corresponding norms, this paper designed temporary support with the method of allowable stress. It was proved that the temporary support met the need of the site construction, both to ensure casting construction quality, but also save construction costs and speed up the construction progress, which provided a new way for the construction of large-span continuous box girder.

Abstract: Increasing numbers of tunnels adopt super large sections due to the advance of design and construction technology, but the calculation method for the loose loads of such tunnels still follows the traditional method for tunnels constructed by the method of whole face excavation. The calculated loads using such method are always lager than their actual values of super large sections tunnels, and as a result the supports for such tunnels are too conservative which lead to unnecessary construction cost. As said, a new calculation method for the loose loads of multi-arch and extra large cross section tunnels (MELCST) is proposed in this paper considering the characteristics of construction for such tunnels. The method accounts for the influences caused by the multi-step construction procedure and temporary support on tunnels. Compared with old methods, this method is more practical and close to field situation, which provides a new idea for calculating surrounding rock loose loads in MELCST. This new method is demonstrated using Luohanshan tunnel of airport-highway in Fuzhou city, China.