Internal excavation method through pile, and foundation pile structure

Abstract

Fill the front end fittings (6) at the prefabricated pile (1) made of concrete, insert the excavating bar (15) that does not have the earth-discharging mechanism, and set the prefabricated pile ( 1). Excavation is carried out while cutting and loosening the foundation according to a diameter greater than or equal to the outer diameter of the prefabricated pile (1), and the excavated soil that has been cut and loosened is compacted on the outside of the prefabricated pile (1) toward the outside. In the formation (26A, 26B) specified in the design, the cement slurry is injected and stirred and mixed to form a solidified mixed layer (29A, 29B) that restores and improves the strength of the foundation. A root fixation layer (30) filled with cement slurry is formed on the pile hole bottom (31) side. The digging head (18) is lifted to the ground, the prefabricated pile (1) is lowered, and the front fitting (13) is positioned in the root fixing layer (30). Compared with the conventional mid-digging pile construction method, it can exert about twice the supporting force, and at the same time, it can greatly reduce the amount of soil discharge.

Description

technical field [0001] The present invention relates to a mid-digging pile construction method in which prefabricated piles are buried while excavating pile holes, and a foundation pile structure formed by embedding prefabricated piles in the pile holes constructed according to the construction method. It is especially effective for occasions where there is a weak stratum on the way to the foundation, and sufficient supporting force cannot be obtained from this stratum. Background technique [0002] In the general construction method of mid-digging and sinking of piles, a digging rod forming a digging head and a soil discharge screw is inserted into the hollow part of the precast pile, and the ground is excavated by the digging rod protruding to the front end of the prefabricated pile, and the prefabricated pile is sunk at the same time. In this case, the digging diameter of the digging head is slightly smaller (about 40 mm smaller) than the inner diameter of the buried prec...

AI Technical Summary

Problems solved by technology

However, the integration of the buried propelling head and the prefabricated pile in the invention of Patent Document 5 is unreliable, and in addition, enlarged excavation cannot be carried out, so the support force reinforcement around the foundation cannot be effectively supported by using the propelling head.

In addition, when the formation at the middle depth does not contain a soft layer, the solidified mixed layer cannot be formed in this part, and the enhancement of peripheral friction cannot be realized.

In addition, the propelling head with a complicated structure cannot be recovered from the supporting foundation, which requires cost

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