Active X-shaped double-row pile foundation pit supporting method

Abstract

The invention discloses an active X-shaped double-row pile foundation pit supporting method. The active X-shaped double-row pile foundation pit supporting method comprises the following steps of (1) driving front-row vertical support piles to the pile bottom designed elevation along the inner side of the edge of a foundation pit, driving inclined rear-row support piles to the pile bottom designedelevation in the pit and meanwhile arranging a water isolation curtain behind the rear-row support piles; (2) arranging a jack on the pile top of each rear-row support pile; (3) arranging crown beamson the front-row vertical support piles and the rear-row support piles, and connecting the crown beams on the front-row vertical support piles and the rear-row support piles into a whole though connecting beams; and (4) excavating a soil body surrounded by the front-row vertical support piles and the rear-row support piles to the pit bottom designed elevation and applying control expansive force to the rear-row support piles through the jacks so as to reduce displacement of the soil body and the pile tops. Through the active X-shaped double-row pile foundation pit supporting method, the displacement of the pile tops can be reduced to a great extent, the bending moment of pile bodies can be reduced, the construction cost can be reduced, the excavation depth can be increased, and the possibility of collapse and damage to the foundation pit can be reduced.

Description

technical field [0001] The invention relates to a foundation pit support method, in particular to an active X-shaped double-row pile foundation pit support method. Background technique [0002] Pile row support is one of the most widely used forms of foundation pit support in China. Compared with the underground diaphragm wall, the pile row structure has many advantages such as simple construction technology, low cost, and flexible layout. Pile row support arranged at intervals is suitable for the situation where there is no groundwater or precipitation outside the pit is allowed. It can also be used for weak water-bearing strata when a water-stop curtain is set or a side-by-side continuous wall is formed with other mixed piles. When the excavation of the foundation pit is relatively shallow, the geological conditions are good, and the environmental requirements (especially deformation requirements) are not high, the support form of cantilever piles can be used. The pile r...

AI Technical Summary

Problems solved by technology

[0004] First, the displacement of the top of the pile with the same excavation depth is large, and the internal force is large, which will cause a large deformation of the ground behind the pile and endanger the surrounding environment

[0005] Second, when the strength of the piles is not enough, it is easy to cause the slope protection piles to break and make the foundation pit unstable, and the excavation depth of the foundation pit is small, and overturning damage is easy to occur when the excavation depth is large, so the support structure needs more Large cross section and insertion depth

However, this technology mainly relies on the hydraulic axial force applied by the horizontal support to actively control the deformation of the foundation pit, which takes up a lot of space, is expensive, and is not environmentally friendly or economical.

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