Construction method for bottom-expanded pile casting by long-spiral drilling and compacted half soil sampling

Abstract

The invention relates to a construction method for bottom-expanded pile casting by long-spiral drilling and compacted half soil sampling. The construction method comprises the following steps: adopting a long-spiral drilling machine provided with a special in-rock drilling bit for construction to a preset pole-hole depth; backfilling rock soil discharged by the long-spiral drilling machine into a pole hole, and adopting the long-spiral drilling machine provided with a special in-rock drilling bit for extruded drilling to the preset depth; installing a reamer at the bottom part of a drilling rod by replacement, and putting into the bottom part of the pile hole for reaming construction; after reaming, taking out the long-spiral drilling machine, installing a multifunctional slag removing drum at the bottom part of the drilling rod by replacement, and putting into the pile hole for slag removing construction; after the residual slag at the bottom part of the pile hole is removed completely, opening a concrete output valve at the bottom part of the multifunctional slag removing drum, and concreting into the expanded bottom of the pile hole by a concrete pump; and lifting into a steel bar cage, and vibrating for positioning the steel bar cage by utilizing a vibrator and the self weight of the steel bar cage. The cast hole pile has the advantages of large force bearing area at the pile bottom, high load bearing force for single pile and strong vibration resistance at the bottom part of the single pile.

Description

technical field [0001] The invention relates to a construction method of reinforced concrete cast-in-place piles, in particular to a construction method of long auger drilled compacted semi-borrowed cast-in-place piles with bottom expansion. Background technique [0002] At present, under the geological conditions where the non-bedrock is the bearing layer, the high-rise and super-high-rise construction projects with extremely large upper loads generally increase the pile diameter and the length of the pile body to increase the bearing capacity of the single pile in order to ensure that the bearing capacity of the foundation is not exceeded. However, lengthening and increasing the diameter of the pile body will inevitably lead to a huge increase in the amount of concrete. Moreover, when the ratio of the length to diameter of the pile body is too large, the bearing capacity and shear resistance of the pile body will be significantly reduced. However, at present, the drilling,...

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Problems solved by technology

[0002] At present, under the geological conditions where the non-bedrock is the bearing layer, the high-rise and super-high-rise construction projects with extremely large upper loads generally increase the pile diameter and the length of the pile body to increase the bearing capacity of the single pile in order to ensure that the bearing capacity of the foundation is not exceeded. However, lengthening and increasing the diameter of the pile will inevitably lead to a huge increase in the amount of concrete, and, when the ratio of the length to the diameter of the pile is too large, the bearing capacity and shear capacity of the pile will be significantly reduced

However, at present, the drilling, bottom expansion, pouring, pile forming and other processes in the construction process of bottom expansion grouting piles require the cooperation of multiple mechanical equipment to complete, the construction efficiency is low, the operation is complicated, and the maintenance cost is high. Therefore, the existing The construction method and equipment of the bottom-expanding cast-in-situ pile seriously restrict the development of the pile foundation industry

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