Active Supporting Method for Foundation Pit with Inclined Double Rows of Pile

Abstract

The invention discloses an active inclined double-row pile foundation pit support method. The following steps are adopted: 1) driving the front row of support piles inclined into the pit along the inner side of the edge of the foundation pit to the design elevation of the pile bottom, The externally inclined rear support piles are driven to the design elevation of the pile bottom, and a water-proof curtain is installed behind the rear support piles; 2) A jack is installed on the pile top of each front support pile; 3) Set crown beams on the front row of support piles and the rear row of support piles respectively, and use connecting beams to connect the crown beams on the front row of support piles and the rear row of support piles into a whole; From the soil body to the design elevation of the bottom of the pit, during or before excavation, use the jack set in step 2) to apply a controlled expansion force to the front row of support piles to reduce the displacement of the soil body and pile top. The invention can greatly reduce pile top displacement, reduce pile body bending moment, reduce engineering cost, increase excavation depth, and reduce the possibility of foundation pit overturning damage.

Description

technical field [0001] The invention relates to a foundation pit support method, in particular to an active inclined 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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