Granule grouting pile of ripple plastic sleeve with hole for strengthening soft soil foundation and strengthening method

Abstract

The invention discloses a grouting pile of a plastic sleeve for strengthening a soft soil foundation and a pile-forming strengthening construction method thereof. The pile consists of a pile cap, a thread sleeve, an earthwork cloth, a joint, a pile body and a pile tip; the top of the sleeve is connected with the pile cap and the bottom of the sleeve is connected with the pile tip, the side wall of the sleeve is provided with an opening hole, the outside of the sleeve is packed by the earthwork cloth, each section of the sleeve is connected by the joint, and the sleeve is filled with granules and grouted with slurry inside so as to form the pile body and a pile periphery as a slurry spreading zone. The pile-forming strengthening method comprises: connecting the sleeve to the depth of the pile length by the joint and then to the pile tip, placing the sleeve and the pile tip into an immersed tube together, beating the sleeve into a foundation by a beating machine, leaving the sleeve and the pile tip in the foundation, feeding the granules into the sleeve and grouting the sleeve to form a slurry scattered material column, spreading a slurry liquid on the pile periphery to form a spreading zone under the grouting pressure or expanding the earthwork cloth outwards to form a gourd pile body, pouring the pile cap on the pile top, and paving a reinforced material and a gravel cushion after the pile body and the pile cap are dried so as to form a composite foundation. The pile type can strengthen the contact action between the pile and the soil, can improve the bearing capacity of the pile body greatly, and is an ideal pile type for strengthening the soft soil foundation.

Description

Technical field [0001] The invention relates to a pile type for treating soft soil foundations, in particular to a corrugated plastic casing granular material grouting pile with holes for strengthening the soft soil foundation and a reinforcement construction method thereof. Background technique [0002] At present, piled embankments have become a common foundation treatment method in highways, high-speed railways, municipalities, airports and other projects. Before the present invention, the embankment piles were mainly flexible piles such as cement-soil mixing piles and rigid piles such as vibrating sunk pipe piles, prestressed pipe piles, and bored piles. At the same time, before the invention of the present technology, a cast-in-place concrete pile with plastic casing, a bulk material pile, a gravel grouting pile, etc., under suitable geological conditions and engineering backgrounds, are gradually being popularized and applied. [0003] Cement-soil mixing piles (including gr...

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Problems solved by technology

[0003] Cement-soil mixing piles (including slurry-sprayed piles and powder-sprayed piles) are flexible piles with low strength and low cost, but the construction quality is not easy to control. The cost of cast-in-place concrete piles is lower than that of prefabricated piles, but vibrating concrete piles have a great impact on the surrounding piles during the vibration construction process, which is prone to pile breakage, difficult quality control and detection, and sometimes the filling coefficient is too large. The influence of surrounding buildings is great; the quality of prestressed reinforced concrete piles is easy to control and detect, the reinforcement effect is good, and there will be no quality problems such as broken piles, but the cost is often quite expensive. At the same time, when high-strength piles are used as embankment piles There is a lot of waste in the strength of the pile body; the grouted pile has no problems such as mud skin and sediment, but the construction cost is high. In addition to the problems of environmental pollution caused by mud treatment, there are also gravels that are not easy to clean. Disadvantages such as wasting materials in the foundation and uneven grouting

Concrete piles with plastic sleeves are constructed by using a large-diameter steel immersed tube with a small-diameter plastic tube inside and enlarging the pile tip. When the disturbance is large and the soil around the pile cannot be squeezed back in time, the strength of the soil around the pile will take a certain amount of time to recover, and the frictional resistance of the pile side can also be fully exerted under the action of the soil squeezing effect and the upper load. However, in actual engineering construction, Due to the limitation of the construction period, the static load test is often required within 28 days. At this time, the bearing capacity is often low, and sometimes it can only reflect the bearing capacity of the pile tip (the bearing capacity of the pile side cannot be fully exerted at this time), and cannot fully reflect the long-term working conditions. The actual bearing capacity, the test shows that the bearing capacity of 90 days is about 20-30% higher than the bearing capacity of 28 days

However, due to the inconvenient detection of the bearing capacity under the long-term working conditions of the actual load, and the lack of a large amount of data on the bearing capacity in this regard, for the sake of safety, the bearing capacity of 28 days is often used for design, making most engineering designs still relatively conservative. design

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