Construction process of rammed and expanded pile

Abstract

The invention provides a construction process of a rammed and expanded pile. The construction process comprises the following steps of preparing bagged dry concrete; preparing an inner pipe, an outer pipe and a reinforcement cage; measuring and setting out; tamping the outer pipe to be inserted into an underground soil body, and sinking the bagged dry concrete into the ground; pouring initial setting concrete into the outer pipe; tamping the inner pipe to be inserted into the underground soil body, and jacking the initial setting concrete into the ground; and tamping the initial setting concrete, and pulling out the inner pipe and the outer pipe at the same time. By adopting the construction process of the technical scheme, the inner pipe and the outer pipe are tamped alternately through a rammer, finally, the initial setting concrete is tamped and expanded to form a bottom ramming and expanding head, pile bottom soil is compacted through ramming of the rammer, due to the fact that the outer diameter of the inner pipe is smaller than the inner diameter of the outer pipe, the outer pipe is tamped first, and then the inner pipe is tamped, so that the concrete is compacted, the sectional area of the pile end is increased through the pile bottom ramming and expanding head, and the loading force of the pile end is increased. The defects that the rammed and expanded pile cannot penetrate through a hard soil layer to enter a pile bottom bearing layer and the side resistance of a uniform-section pile body is small are overcome.

Description

technical field [0001] The invention belongs to the technical field of construction engineering, and in particular relates to a construction technology of tamping and expanding piles. Background technique [0002] In construction engineering, piles are classified into friction piles, end-bearing piles, and friction end-bearing piles according to the force conditions. The bearing capacity of piles is composed of pile side resistance and pile end load capacity. Usually, the way to increase pile bearing capacity is to increase pile side resistance or pile end resistance through technical means. The tamping and expanding pile is to sink the casing into the ground by hammering with vibrating sinking equipment or diesel hammer, and use the column hammer or diesel hammer to tamp the dry hard concrete in the casing to form a tamping and expanding head at the bottom of the pile, and then place the reinforcement cage and pour A bottom-expanding pile formed by lifting a concrete pipe ...

AI Technical Summary

Problems solved by technology

The vibrating immersed tube or the diesel hammer hammering the immersed tube has the disadvantages of high noise, which does not meet the environmental protection requirements and the immersed tube has poor footage capability, and it is difficult to penetrate the harder soil layer and enter the better bearing layer. The bearing capacity of the single pile is low, which is difficult to meet Requirements of Modern Buildings for Bearing Capacity of Pile Foundations

Rammed and expanded piles strengthen the soil at the bottom of the pile by hammering, and the hammering forms a rammed enlarged head, which expands the cross-sectional area of ​​the pile end and increases the resistance of the pile end, but it has high noise, poor pile formation efficiency, and shallow hole depth, etc. ills

The hammering and vibrating tube sinking process of rammed and expanded piles has poor sinking ability and low efficiency, and cannot change the shape of the pile body, and cannot make further progress in improving the pile side resistance. How to make the pile length of rammed and expanded piles longer, the pile The side resistance is greater, or how to make the bottom of the threaded pile free of empty soil, and the cross-section of the pile bottom is larger, so that the resistance of the cast-in-situ pile can be further improved no matter the resistance at the side of the pile or the resistance at the pile end, which has a higher bearing capacity and is more energy-saving. Environmentally friendly friction end-bearing piles have become a major problem in the research of pile foundation technology at the present stage.

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