Construction method of pore-forming pouring pile in dry work of super-large-diameter full-steel pipe casing

Abstract

The invention discloses a construction method of a pore-forming pouring pile in the dry work of a super-large-diameter full-steel pipe casing. The method comprises the steps of a, measuring a pile position; b, embedding an orifice steel pipe casing; c, excavating a second pile hole section; d, hoisting an inner steel pipe casting in the second pile hole section, and filling clay in a clearance between the second pile hole section and the inner steel pipe casing, wherein the outside diameter of the inner steel pipe casing is less than the inside diameter of the second pile hole section; the lower end surface of the inner steel pipe casing is supported on a supporting layer of bed rock; d, downwards excavating below the second pile hole and expanding the hole until reaching the preset depth, and then pouring concrete. According to the method, the mode of sequentially excavating two pile hole sections and forming holes through a rotary drilling rig is carried out and has the beneficial effects of being high in safety, high in construction efficiency and low in labor intensity by being compared with the mode of manually excavating hole for constructing the pile.

Description

technical field [0001] The invention relates to a construction method for hole-forming cast-in-situ piles, which is especially suitable for the construction method of all-steel casing dry-operation hole-forming cast-in-situ piles with super large diameter (the pile diameter is larger than the maximum diameter of the drill bit of a rotary drilling rig). Background technique [0002] According to the standard "Building Pile Foundation Technical Specifications" JGJ94-2008: During the construction of building pile foundations, according to the size of the pile diameter (design diameter d), it can be divided into the following three categories: (1) Small diameter piles: d≤250mm ; (2) Medium-diameter piles: 250mm<d<800mm; (3) Large-diameter piles: d≥800mm, and in the actual construction process, super-large-diameter piles (such as diameters of 2600mm and 2800mm) are often encountered. The diameter of the expansion head at the bottom reaches 5500mm, and its engineering geolog...

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Problems solved by technology

[0003] Because the pile diameter is too large, the existing rotary drilling rig hole forming method (that is, using the drill pipe carried by the drilling rig to mechanically form the hole, and then reaming the hole until the pile is formed after the depth reaches the design requirements), due to the expansion of the machine itself It is difficult for the hole device structure and reamer to reach the size of the enlarged head of the large-diameter pile in this project, and it is difficult to meet the actual construction needs of the above-mentioned working conditions, and there are still large disturbances to the bearing layer during the reaming construction process, and the pile bottom Deficiencies such as inconvenient inspection and control of sediment and low bearing capacity of single piles

[0004] In the prior art, the method of manually digging holes is usually adopted for the above-mentioned working conditions, although it has the advantages of little disturbance to the soil around the hole during the pile forming process, low noise, and close contact with the pile body hole wall. The strength layer is easy to check, the sediment at the bottom of the pile should be controlled, and the quality is easy to guarantee. However, the disadvantages of this method are: the safety control is difficult, and the construction risk is high. Usually, the concrete retaining wall construction must be carried out after digging 1m, and the labor intensity is high. The construction period is longer and the cost of safety measures is higher

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