Method for judging piping seepage damage of foundation pit containing confined water of soft soil layer

Abstract

The invention relates to a method for judging piping seepage damage of a foundation pit containing confined water of a soft soil layer, in particular to a method for judging piping seepage damage of a foundation pit containing aquitard confined water of a soft soil layer. The method comprises the following steps of: deducing a piping seepage damage equation of pit bottom soil according to the soil stability condition of a seepage surface at the foundation pit bottom, and then collating the piping seepage damage equation to obtain a critical piping damage seepage gradient; then establishing a foundation pit two-dimensional seepage computation model to compute a maximum seepage gradient of the pit bottom soil; and judging whether the pit bottom soil has seepage damages or not. Compared with the prior art, the invention overcomes the defect that piping damage phenomena such as quick sand, flowing soil or sand boil similar to boiling, which occur at the bit bottom, can not be explained by applying the strength theory and other methods.

Description

technical field [0001] The invention relates to a method for judging the inrush failure of a pressurized water foundation pit in a soft soil layer, in particular to a method for judging the inrush seepage damage of a pressurized water foundation pit in a soft soil layer containing an impermeable layer. Background technique [0002] In recent years, with the rapid development of urban underground railways, high-rise buildings, civil air defense projects and other infrastructure in China, the number of deep foundation pit projects is increasing, and the geological conditions and environment of deep foundation pit engineering excavation and construction are also becoming more and more complex. The engineering accident rate and loss Also getting bigger and bigger. In deep foundation pit engineering, a work related to the overall situation is groundwater prevention and control, especially in coastal soft soil areas, groundwater is the natural enemy of deep foundation pit engineer...

AI Technical Summary

Problems solved by technology

In actual engineering, the water-resisting layer at the bottom of the foundation pit under pressure in the soft soil area is a heterogeneous elastic-plastic body distributed in layers. It is not reasonable, and when the ratio of the thickness of the aquifer soil to the span of the foundation pit is large, the simplified beam or slab model analysis does not conform to the definition of beams and slabs

In addition, for the confined water foundation pit in the impermeable layer, the inrush damage often manifests as quicksand, quicksand or seepage damage similar to "boiling" water spraying sand at the bottom of the pit. Water gushing, sand gushing at the bottom of the deep foundation pit of the tunnel in the open excavation section, and water gushing and slurry gushing at the bottom of the pit during the excavation of the deep foundation pit of a 24-story building in a certain city. inexplicable

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