Study On Coupling Mechanism Effect Of Steel Support In Diaphragm Wall Retaining Structure

Internal support and underground continuous wall are commonly used support forms for deep foundation pit engineering in the world.Steel support is widely used in foundation pit support by installation,disassembly,flexible,quick and reusable characteristics.The underground diaphragm wall is widely used in subway and other super deep foundation pit with good water stop effect,good integrity and high strength.In the support.But at present,the theoretical research of foundation pit support in China is a backward engineering practice.The design department of foundation pit is often used to meet the national or local standards and norms to refer to a large number of previous engineering experiences.Based on the background and support of the deep foundation pit of the Taiyuan subway station,this paper analyzes the coupling mechanism of the steel support and the ground wall,uses the calculation software of the deep foundation pit structure calculation and the method of FLAC3 D numerical simulation,and aims at the preloading of the steel bracing and the space arrangement of the steel bracing.The influence of retaining structure on stability of deep foundation pit is studied.The influence of the pre axial force and spatial arrangement of steel support on the stability of the retaining structure is obtained.On the basis of this rule,the optimal pre axial force scheme for steel support and the optimal space layout scheme for steel support are obtained.Through structural calculation and simulation study,it is found that increasing the pre axial force of steel support can reduce the larger settlement range of soil layer in horizontal and vertical directions.When the preloading force is increased to 0.3 times the standard axial force,the preloading force will continue to increase.At this time,the maximum settlement of the soil layer is less obvious,but the larger steel support preloading force is unfavorable to the internal force of the diaphragm wall.The maximum axial force of the steel support level is increased by 15.2% for each increase of 0.5m.For the vertical spacing between the two steel braces in the upper part of the foundation,the axial force increases by 15.61%,and the vertical spacing between the lower two steel braces is reduced by each reduction of the support axis force of 0.5m fourth road 10.62%,the horizontal spacing and the vertical of the steel support.The vertical spacing has great influence on the final axial force of the steel support.The vertical spacing of the steel support has great influence on the internal force of the diaphragm wall.In this paper,through the study of the interaction mechanism of the joint deformation of steel braces and ground walls,the concept of coupled support is put forward,the steel support and the ground wall are taken as a whole,and the mutual influence and interaction of the two are concerned,which provides a new idea for the design of foundation pit support,which has been carried out once for the development of the foundation pit support theory.The discussion of meaning.