中文摘要：

地铁建设中地下水影响是环境损伤事故最重要的诱因，分析了近年地铁施工及渗害诱发地层沉降、建筑坍塌的典型工程事故。鉴于泡沫剂改良渣土是盾构隧道施工中维护开挖面稳定及控制地层渗害的极端重要性，研制了一种新型泡沫剂发泡装置，进行了泡沫剂改良地层的系列实验研究，获得了泡沫剂对粘性土和砂土的渗透性影响、流动性影响的实验规律，可为盾构施工中开挖面稳定性与渗害控制提供重要依据。

英文摘要：

The ground water is one of the most important factors which induced ground environment damages and accidents in metro tunneling projects. This paper presents the recent typical ground seepage damages and the induced subsidence failure accidents in the metro engineering in China. Since the important contribution of the foamed soil in preventing the seepage damage and stabilizing the shield tunneling face, a new foam generator is developed and a series of experiments are conducted for foam modified soils in this paper. The tests disclose the experimental law of permeability and fluidity for foamed clays and sandy soils. This research will undoubtedly provide the reference for foamed soil stabilizing the tunneling face and preventing ground seepage damage in metro shield tunneling construction.