粉砂地基深基坑工程土体渗透破坏机理及其影响研究

Research on deep foundation pit excavation due to seepage failure of soil

在砂土和粉土地区,渗透破坏是威胁基坑稳定性和周围环境的主要因素。基坑工程是由土、水以及围护结构组成的一个复杂系统,影响基坑工程渗透破坏的因素很多。在总结前人对土体渗透破坏与基坑工程渗透破坏模式的研究基础上,结合渗流对土体性质影响的试验成果,提出了考虑渗流、开挖卸荷以及围护结构变形共同作用的基坑工程渗透破坏分析方法,并分析了均质地基基坑工程的渗透破坏模式。将该方法运用于某粉砂地基基坑渗透破坏工程实例,通过有限元数值模拟,揭示了渗透破坏过程及其对围护结构的影响。通过对该基坑工程实例的分析认为,在进行基坑工程设计时不仅需要进行防止流砂、管涌等验算,还需考虑基坑工程整体破坏的可能性。

In the area of sandy and silty soil, seepage is the main factor that threatens the safety of foundation pit and surrounding environment. The complex system of foundation pit is composed by soil, water and surroundings, and the factors of seepage failure are complicated. Based on the former analysis of seepage failure of soil, a method for analyzing foundation pit seepage failure model is proposed; the method can considers the influences of seepage, excavation and the deformation of surroundings. The foundation pit seepage failure model in homogeneous soil is gained by this method. According to the finite element numerical simulation results of a practical project, the process of seepage failure is gained. The conclusions of those results show that not only the checking computations of flowing sand and piping should be made, but also the unitary failure of foundation pit system should be considered.