Mixed cast-in-place pile forming device and method

Abstract

A mixed cast-in-place pile forming device comprises a pile machine, a threaded drill pipe and two halved nuts provided with nut combining mechanisms; the halved nuts are symmetrically mounted on the left side and the right side of the threaded drill pipe; the threaded drill pipe is connected with a threaded drill bit and is arranged to have a trapezoidal thread; the thread pitch and the spiral direction of the threaded drill pipe are consistent with those of the threaded drill bit; and according to the nut combining mechanisms, first hinge points are arranged in outer diameter centers of the two halved nuts respectively, each first hinge point is connected with a jack, the jacks are connected on the two sides of a chassis of the pile machine through second hinge points respectively, third hinge points are arranged on peripheries of the halved nuts, are used as rotating centers of the halved nuts and are connected with two sides, close to the center, of the chassis of the pile machine, and the jacks are arranged to be controlled electro-hydraulically and automatically. With the device, the carrying capacity of piles can be remarkably improved, construction materials can be saved, the cost of a pile foundation project can be reduced, and meanwhile the construction efficiency and the construction quality of the pile foundation project can be improved.

Description

Technical field [0001] The invention relates to a pile foundation of a civil construction project, in particular to a pile forming device and a method for a mixed cast-in-place pile with a cylindrical pile in the upper section and a threaded cast-in-place pile in the lower section. Background technique [0002] my country’s coastal cities, rivers and towns around the lake, these areas are mostly deep and soft soil areas; the current pile foundations in engineering construction mainly use friction-type cylindrical piles, and the end-bearing friction piles in the soft soil layer of the foundation, The frictional resistance between the side surface of the pile and the soil around the pile accounts for about 70-90% of the bearing capacity of the pile; however, because the side resistance of the soft soil pile is relatively small, the friction-type cylindrical pile seriously restricts the piles in existing engineering construction. The increase in bearing capacity value. [0003] If a sp...

AI Technical Summary

Problems solved by technology

[0002] my country's coastal cities, towns along the river and around the lake, these areas are mostly deep soft soil areas; at present, the pile foundations in engineering construction mainly use friction-type garden column piles. Among the end-bearing friction piles in the soft soil layer of the foundation, The friction resistance between the side surface of the pile and the soil around the pile accounts for about 70-90% of the pile bearing capacity value; but because the side resistance of the soft soil pile is small, the friction type garden column pile seriously restricts the performance of the pile in existing engineering construction. Increased bearing capacity

[0003] If a spiral pile is used, the screw thread of the spiral pile is embedded in the soil layer to show that it has a significant advantage in pullout resistance compared to the garden column pile; but it has not been seen that the spiral pile is used in civil engineering projects at home and abroad. In the pile foundation practice, this is because most of the spiral piles mentioned at present are long spiral steel pipe threaded piles made of steel pipes welded with steel plate spiral leaves in the factory. The rotating power of the pile driver uses forward rotation (clockwise rotation) to pressurize and screw the drill bit with helix into the soil layer to the required elevation, start pumping concrete, and use reverse rotation (counterclockwise rotation) to pull up, the drill bit with helix If the gap left in the soil layer when pulling up can be reversed and pulled up at a uniform speed according to the pitch of the spiral, the spiral gap left in the soil layer can be quickly filled by pressure pouring concrete, and the pouring can be realized as a spiral. Concrete spiral piles; however, countless practices have proved that it is impossible to reverse and pull up according to the spiral pitch at a uniform speed; this is because the spiral piles pass through soil layers with different hardness and hardness, and the strength of most soil layers cannot support The helix reverses at a constant speed according to the pitch, pulls up and spins back, so the cast-in-place pile with a helix cannot be formed

[0004] The invention patent 201410186000.5 "A Threaded Cast-in-situ Pile Device with Nut Engagement Synchronization Mechanism" has been authorized by the inventor, which includes a drill bit and a nut engagement synchronization mechanism. The drill bit is composed of a drill tip, a drill bit body and a spiral body. The upper part of the spiral body is fixed with a connecting belt A hollow drill rod with external threads, a tooth-shaped joint is provided between the drill tip and the drill body, and the nut engagement synchronization mechanism includes a pair of half nuts and a two-way screw rod symmetrically arranged radially outside the pair of half nuts. The pair of half nuts Cooperate with the external thread of the hollow drill rod, the pitch of the external thread of the hollow drill rod is the same as that of the helix, and the two-way screw rods are equipped with transmission nuts. Positioned on the pile driver chassis of cast-in-place piles; the advantage of this invention patent is that when the nut engages the threaded drill pipe, it can be screwed in or out at a uniform speed regardless of forward or reverse rotation, which significantly improves the bearing capacity of the pile. , greatly reducing the cost of pile foundation engineering; however, its shortcoming is that it cannot implement mixed cast-in-situ piles especially for the different lateral resistances of soft soil piles, and the second is that the invention patent uses manual control of the nuts. Construction efficiency is low

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