Water-stopping deep foundation pit excavation method and structure thereof

Abstract

The invention provides a water-stopping deep foundation pit excavation method. The water-stopping deep foundation pit excavation method comprises the following steps that (1) surveying and setting out are carried on in the range of a deep foundation pit to be excavated; (2) retaining piles are driven downwards along side walls of the deep foundation pit to be excavated, jet grouting piles are driven into gaps between the retaining piles after the adjacent retaining piles are driven at intervals, so that a water-stopping continuous wall is formed, and the water-stopping continuous wall extends into a bearing layer below a basic design elevation; (3) the bearing layer below the basic design elevation is a permeable layer, mortar grouting or jet grouting is conducted on the bearing layer below the basic design elevation, so that a water-stopping bottom plate is formed at the top of the bearing layer, and the retaining piles and the jet grouting piles extend into the water-stopping bottom plate. According to the water-stopping deep foundation pit excavation method, underground water outside the deep foundation pit can be isolated from a working plane inside the deep foundation pit in the construction process, as a result, a large area of underground water surrounding the deep foundation pit does not need to be drained when the deep foundation pit is excavated, and water resources are protected.

Description

technical field [0001] The invention relates to the construction field, in particular to a water-stop excavation method for a deep foundation pit and its structure. Background technique [0002] For the deep foundation pits of high-rise buildings, most of the foundations are set below the groundwater level. In order to achieve the purpose of foundation construction, it usually takes a long time to drill wells and pump water outside the building foundations. Can be excavated for construction. [0003] But, adopt above-mentioned method, there are following disadvantages: [0004] 1. Carry out construction according to the engineering geological survey report. If the groundwater level and water permeability in the survey report are accurately expressed, and the well drilling and pumping are smooth and the water volume is uniform, the construction will be convenient. Otherwise, it is necessary to drill wells in different positions, make up wells, and repeat construction to ach...

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Problems solved by technology

[0005] 2. Pumping equipment, accessories, pipelines, ground drainage ditches, power supply, equipment maintenance, on-duty and other work have to be done for a long time, day and night until after the completion and acceptance of the building. Generally, the continuous pumping of water for 1-2 years, even several years, cause waste of various resources

[0006] 3. According to the layout of the building, the extraction range of the precipitation funnel and the distribution of the water surface make the groundwater in other areas outside the scope of the building be pumped out, and the precious fresh groundwater is drawn out for nothing, resulting in a waste of economy and resources

[0007] 4. Long-term extraction of large amounts of underground water and crevice water will take away the surrounding mud and sand, affect the settlement of surrounding buildings, and cause the ground to deform and crack, causing serious negative impacts and causing emotional instability of the surrounding people

[0008] 5. The extracted groundwater cannot be reused, and it is discharged into rivers in vain, and the mud and sand sink to the bottom of the river, blocking the channel for infiltrating water to supplement groundwater

[0009] 6. After the deep foundation pit is pumped, the voids of the surrounding building foundations will increase, and the bearing capacity will decrease. The foundation needs to be remedied, which will increase the cost input and cause serious economic losses to the country.

[0010] 7. The original deep foundation pit retaining wall is not used for water stop and cannot protect the loss of water source outside the foundation pit

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