Method for sealing foundation pit pressure reduction well

Abstract

The invention discloses a method for sealing a foundation pit pressure reduction well, which relates to blockage for a deep foundation pit pressure reduction well. The well sealing method comprises the following steps: (1) putting a grouting pipe into a well pipe to a bearing water layer I, and reserving a clearance between the bottom end of the grouting pipe and the bottom end of the well pipe; (2) filling a melon seed shaped sheet to an interface between a stable waterproof layer I and a bearing water layer I; (3) mounting a closed ring on the layer filled with the melon seed shaped sheet; (4) casting plain concrete into the well pipe above the closed ring; (5) grouting the well pipe under the closed ring by using the grouting pipe through pressure to fully block the clearance between the well pipe and a well hole at the interface between the stable waterproof layer I and the bearing water layer I; and (6) casting floor concrete to the whole foundation pit bottom plate. The method has the advantages that the method is simple to implement, the process is simplified and the expense is not increased; moreover, the pressure reduction well is thoroughly blocked at the interference between the stable waterproof layer I and the bearing water layer I, and the risk of bearing water leakage does not exist.

Description

technical field [0001] The invention relates to a foundation pit decompression well, in particular to a well sealing method for a deep foundation pit decompression well. Background technique [0002] In densely populated cities, limited land resources make the per capita land use area very small, so modern buildings tend to develop in the air and underground, especially underground engineering, which has developed very rapidly in recent years. The construction of underground buildings generally requires the excavation of foundation pits. Foundation pits are temporary pits excavated for building foundations. [0003] From the surface down, according to the different characteristics of the soil layer, it can be divided into surface water layer, stable aquifer I, confined aquifer I, stable aquifer II, confined aquifer II, etc. Pressure is balanced under normal conditions. However, when the foundation pit is excavated to a certain depth, the pressure balance between the stable...

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Problems solved by technology

[0009] 2) The grouting plugging is only limited to the well pipe, and there is no grouting plugging measure for the gap between the mud-filled wellbore and the well pipe, that is, the clay ball backfill layer and the clay backfill layer

[0013] 3) The interface of the well sealing is limited to the sealing inside the well pipe. The gap between the well hole and the well pipe causes the pressurized water to leak directly under the foundation pit floor, and the structural bottom plate in the foundation pi

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