Construction method of long spiral pilot hole for prestressed pipe pile in ultra-deep and ultra-thick dense sand layer

Abstract

The present invention discloses an ultra-deep and extra-thick dense sand stratum prestressed pipe pile long spiral lead hole construction method. The method comprises the following steps of: S1: siteformation and drill stem equipping: performing leveling and compaction for a site prior to place taking, or bedding a steel plate to facilitate place taking of a pile machine, and regulating equippingof the corresponding quantity of drill stems according to the depth of the lead holes to ensure the lead hole operation flow construction, wherein two lead hole drills are arranged on the site; and S2: location, paying-off and place taking of the pile machine: employing a total station to perform laying-off for preset lead hole stake positions, taking a drill machine in place to complete correction of the vertical degree of the drill stem and the centering of the center of the drill, and after location, putting down a support oil cylinder at the lower portion of a front-end mast and two support oil cylinders at the tail portion of the machine body of the drill machine. The ultra-deep and extra-thick dense sand stratum prestressed pipe pile long spiral lead hole construction method can extend the drill stem at will through connection according to pore-forming demands by employing a design of the hexagonal joint of the drill stem, can effectively ensure the reliable connection of the drill stem by only using a dual-way fixed plug pin after the drill stem is inserted when being connected and can meet the construction of an overlength pile hole.

Description

technical field [0001] The invention relates to the technical field of construction methods for long spiral lead holes, in particular to a construction method for long spiral lead holes of prestressed pipe piles in ultra-deep and ultra-thick dense sand layers. Background technique [0002] Prestressed pipe piles have the advantages of low cost, energy saving and environmental protection, short construction period, good quality of pile body, and high bearing capacity of single pile. When the design pile length of the prestressed pipe pile is not less than 50m, and when an ultra-thick and dense sand layer of 8-10m is encountered at an ultra-deep position about 40m below the ground, the construction of the prestressed pipe pile will be difficult to penetrate, and it is usually necessary to take measures to introduce holes To solve the above-mentioned problems by penetrating the sand layer, the commonly used drilling methods for penetrating dense sand layers include rotary drill...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a construction method for long spiral pilot holes of prestressed pipe piles in ultra-deep, ultra-thick and dense sand layers, which has the advantages of safety, high efficiency, and low cost, and solves the problem of negative friction on the side wall of piles that is easily generated by rotary excavation pilot holes , which is unfavorable for exerting the side friction of pipe piles. In addition, the comprehensive cost of rotary excavation for hole formation is relatively high, and mud hole formation is not conducive to the civilized construction of the site.

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