Time-effect analysis of deep foundation pit excavation and support in soft clay soil areas

The space-time effect during soft clay soil areas deep foundation pit excavation is an objective reality. The time taking of excavation is an important index of foundation designment and construction parameters determination. In this paper, based on one station foundation pits of NO.2 subway in Wuhan city, the 2-D numerical simulation model which consider the excavation time-effect is established by professional software PLAXIS. During the deep foundation pit excavation in soft clay soil areas, the laws of time and deep pit supporting deformation in consideration of different factors are discussed and analyzed. The results show that the following factors have a great influence on the space enclosing structure deformation, internal force and settlement in soft clay soil areas. Such as the excavation time of each layer of soft clay soil excavation, soil parameters, exposure time without support and so on. The time taking of excavation and exposure time without support should be controlled strictly during construction.