超挖对软土基坑工程稳定性的影响分析

Analysis of the Influence of Over Excavation on Stability of Soft Soil Foundation Pit

为了研究软土基坑超挖对稳定性的影响,结合珠海地区软土基坑典型案例,分析了超挖对基坑支护工程及基础工程的影响。结合理论计算,分析了基坑在未超挖和超挖条件下支护结构的变形和弯矩变化。研究表明:在局部超挖工况下,由于软土的流变性和触变性,会导致主基坑支护结构位移超限,甚至出现坑底隆起、深层滑移以及工程桩的破坏。建议采取加宽、加深坑内加固设施,管桩后搅拌桩加固以及增加桩顶放坡等一种或多种方法相结合的形式来保证基坑的安全和稳定。研究结果为类似软土基坑的超挖施工提供理论借鉴。

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 calculation,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 condition 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 ensure 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 results provide theoretical reference for the over-excavation construction of similar soft soil foundation pits.