Abstract:

In order to study the influence of over-excavation on the stability of soft soil foundation pit，

combined with the typical case of soft soil foundation pit in Zhuhai area，the influence of over-excavation on

foundation pit support engineering and foundation engineering is analyzed.Combined with the theoretical cal⁃

culation，the deformation and bending moment of the supporting structure of the foundation pit under the

condition of no over-excavation and over-excavation are studied.The research shows that under the condi⁃

tion of local over-excavation，due to the rheology and thixotropy of soft soil，the displacement of the main

foundation pit supporting structure will exceed the limit，and even the bottom heave，deep slip and the de⁃

struction of engineering piles will occur.It is suggested that one or more methods should be combined to en⁃

sure the safety and stability of the foundation pit，such as widening and deepening the reinforcement in the

pit，strengthening the mixing pile after the pipe pile and increasing the slope of the pile top.The research re⁃

sults provide theoretical reference for the over-excavation construction of similar soft soil foundation pits.

Key words:

soft soil foundation pit, over excavation, supporting structure, stability