Numerical Simulation and Analysis of Thermal Stress on Restressed Assembly Steel Struts System in Foundation Excavation

Abstract

When using horizontal internal bracing system in large span deep foundation pit, the influence of temperature effect on bracing system must be considered. Based on the long-term thermal stress monitoring of a project in the west of Hangzhou, this paper studied the influence of Angle brace temperature effect on the foundation pit enclosure structure after excavation to the bottom by using three-dimensional finite element model. When the strut temperature rises, the strut axial force increases. The longer the length is, the higher the axial force rises. The horizontal displacement of the surrounding wall and soil will be in the external direction of the pit, which is conducive to the stability of the surrounding system. The second layer struts are more affected by the temperature effect than the first layer struts, and the combined action of the two struts makes the surrounding wall produce greater displacement. The pouring of the bottom plate makes the strut subject to the temperature effect to generate greater axial force, the second layer struts change more violently, and at the same time reduces the displacement and deformation of the retaining structure. When the temperature drops, the strut axial force decreases and the horizontal displacement of the retaining structure to the pit increases, which is not conducive to the stability of the system. At this time, the reinforcement of the nearby soil body can be considered to reduce the deformation of the soil body and the retaining wall.