基于极限分析定理,以初期无支护基坑的竖直坑壁为研究对象,通过运用数学方法分析其特定滑动面—螺旋对数滑动面,得出了无支护基坑竖直开挖的临界深度和潜在破裂面的大小与形状,着重分析了含水率以及饱和度对无支护基坑开挖的影响。 Based on the limit analysis theorem, the vertical pit wall of unsupported foundation pit is taken as the research object. By using mathematical method to analyze its specific slip plane - spiral logarithmic slip surface, the vertical excavation of unsupported foundation pit is obtained The critical depth and the size and shape of the potential rupture surface, the impact of moisture content and saturation on the excavation of unsupported foundation pit is analyzed emphatically.