Influence Of Temperature Effect On Force And Deformation Of Multi-Braced Diaphragm Wall Retaining Structure

With the development of building space to the underground, a large number of deep foundation pit engineering has emerged, meanwhile, the conditions and environments of construction of deep foundation pit engineering are becoming more and more complex, and the engineering is more and more difficult, so it is imperative to improve the security of deep foundation pit engineering. As a cause for foundation pit accident, the influence of environmental temperature changing on deep foundation pit engineering should not be ignored. The force and deformation affected by temperature of multi-braced diaphragm wall retaining structure, which is widely used in foundation pit engineering is studied in this paper. Finite element software is used in this article to simulate the construction process of multi-braced diaphragm wall and its force and deformation affected by temperature. By comparing the force and deformation of retaining structure with and without the temperature change, the influence of temperature effect on multi-braced diaphragm wall retaining structure and the influence of different factors on temperature effect of retaining structure are explored. And suggestions with reference value for design and construction of engineering are obtained. The main researches and conclusions are as follows:(1) Finite element software ABAQUS is used to simulate the temperature effect of multi-braced diaphragm wall retaining structure, in addition, the selection of parameters and the method of modelling is explained in detail. And a simulating about an example of foundation pit engineering is made with this method, then the simulation results are compared with the measured results to verify its feasibility. By comparing the model with and without the temperature effect, it is known that the simulation results with the temperature effect is closer to the measured results than that without the temperature effect. So considering the influence of environmental temperature changing in design and construction process of practical engineering is suggested.(2) With one deep foundation pit engineering as background, the benchmark model is established, and the standard of comparison is made, meanwhile strut axial forces and lateral displacement of diaphragm wall are selected as the main inspection items, then the influencing factors on the percentage of force and deformation caused by temperature effect in the total force and deformation can be researched. The results show that temperature effect of multi-braced diaphragm wall retaining structure is influenced by the characteristics of soil and braces to some extent, while the characteristics of braces influence more.(3) The benchmark model is still selected as the research object. The influence of the different temperature field and different construction stages affected by temperature field on temperature effect of multi-braced diaphragm wall retaining structure is explored, in order to put forward the suggestion to the design and construction. Through the analysis, it is found that for the situation which temperature change occurred in construction process, the maximum appearing in the construction process should be as selected as basis of designing the construction scheme. And, the influence of environmental temperature change which exists in the whole stage and after completing the foundation pit excavation is less than the influence of the same temperature change which exists in a certain excavation stage. Besides, for the project with a longer construction period as well as the temperature variation is across its whole excavation period, when the environmental temperature variation is as much as 30?, the extent of variation of strut axial force is also above 24% even if the environmental temperature return to the original state, namely the strut axial forces are likely to exceed the designed allowable value.