High-pressure circulating grouting micro-steel pipe pile and its construction method

Abstract

The invention discloses a high-pressure circulation grouting minitype steel pipe pile and a construction method thereof. The minitype steel pipe pile comprises a minitype steel pipe, a cement static slurry filling body, a cement static slurry protective layer and leakproof lag piles. The construction method comprises the following steps: (1) carrying out geological survey; (2) designing the minitype steel pipe pile; (3) formulating a scheme; (4) carrying out rotary jet grouting treatment on a slurry leaking layer; (5) carrying out pipe-following drilling; and (6) pouring the cement static slurry filling body and the cement static slurry protective layer, wherein the leakproof lag piles are applied to engineering of an underground soil body with the slurry leaking layer. According to the invention, advantages of the minitype steel pipe and cement static slurry are combined, and the high-pressure circulation grouting technology is adopted to form the cement static slurry filling body andthe cement static slurry protective layer on the internal and external parts of the minitype steel pipe, so that problems about pipe-holding and jamming of a drilling tool caused during the forming process of the minitype steel pipe pile are solved, and corrosion resistance of the minitype steel pipe pile and frictional resistance between the soil bodies are improved; and in addition, the leakproof lag pile technology better solves the problems about slurry leakage during pipe-following drilling and the pile forming and grouting processes.

Description

technical field [0001] The invention relates to the technical field of building pile foundations, in particular to the construction technology of high-pressure circulating grouting miniature steel pipe piles. Background technique [0002] In recent years, with the rapid advancement of my country's urbanization process, more and more construction projects are forced to choose to be carried out under the conditions of narrow construction space and complex geological structures. However, it is difficult to use pile types with larger diameters in pile foundation engineering To meet the narrow space conditions of the construction site, it is difficult to meet the bearing capacity requirements of reinforced concrete piles with small pile diameters; in addition, affected by engineering design and construction technology, many geological conditions that are not handled perfectly are becoming the main danger of building tilting settlement source, resulting in the problem of deflection ...

AI Technical Summary

Problems solved by technology

However, the existing micro-steel pipe piles have the following three major problems in engineering application: ① For the filling foundation, the micro-steel pipe piles face the problems of pipe holding and drill sticking during the drilling process, making it difficult to form a pile; ② due to the micro-steel pipe piles The pile is located in a complex underground environment and is severely corroded by salt such as sulfate in the soil. If the anti-corrosion protection of the micro-steel pipe pile is not properly handled, it will directly affect the service life of the micro-steel pipe pile; ③The surface of the micro-steel pipe pile is relatively smooth And it is in direct contact with the soil, so the relative friction between the pile and soil is weak, and it is difficult for the soil between the piles to form a strong frictional resistance under the stress state of the micro steel pipe pile, so that the bearing capacity of the micro steel pipe pile Therefore, in engineering applications, the design method of end-bearing piles is mostly used for micro steel pipe piles, which will inevitably cause waste of materials for micro steel pipe piles, and will prolong the project period and increase the project cost

[0003] The existing micro-steel pipe piles mostly adopt the following two methods, but neither of them is suitable for the narrow construction space environment: ① Mechanical drilling to the designed pile end depth, and then put the micro-steel pipe into the hole; ② Hammering, Sink the steel pipe to the designed pile end depth by means of static pressure and vibration

In addition, the existing engineering treatment measures to improve the durability of steel pipe piles and enhance the friction between steel pipe piles and soil mainly include the following methods, but there are serious shortcomings in the application of micro steel pipe piles: ① Coating Anti-corrosion method: the durability of steel pipe piles is improved by painting anti-corrosion agents on the outer wall of steel pipes, but it is difficult to guarantee the long-term anti-corrosion effect, and for deep long piles, a large amount of anti-corrosion agents is required, which brings raw material costs and anti-corrosion coating The increase in the amount of agent engineering has led to a significant increase in the cost of the project; ② Hole opening method: open holes in the side wall of the steel pipe, and use pressure grouting to make the cement slurry enter the soil to form a tree root structure to provide strong friction resistance, but the hole will cause the steel pipe The integrity is reduced and the bearing capacity is reduced. At the same time, the split grouting is easy to disturb the soil around the pile, which seriously affects the structural properties of the soil; ③ Internal and external grouting method: place grouting pipes on the inside and outside of the steel pipe for grouting, although it can achieve cement slurry wrapping Steel pipes are used to improve durability and enhance frictional resistance, but require a large space for construction operations, and are not suitable for the narrow space environment where micro-steel pipe piles are located in the process of deflection correction and reinforcement

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