Composite pile structure capable of draining firstly and then reinforcing

Abstract

The utility model relates to the field of foundation engineering construction, in particular to a composite pile structure capable of firstly draining water and then reinforcing, which comprises a geogrid rolled into a barrel shape, a layer of geotextile fixed on the inner side surface of the geogrid, a grouting pipe vertically inserted on the inner side of the geotextile, a plurality of radial through holes arranged on the side wall of the grouting pipe at intervals, and a plurality of drainage holes arranged on the side wall of the grouting pipe. The surrounding area between the outer wall of the grouting pipe and the inner wall of the geotechnical cloth and the grouting pipe are filled with broken stones, cement mortar injected after soft soil drainage is poured into gaps among an inner cavity of the grouting pipe, the radial through holes and the broken stones, and the grouting pipe, the broken stones and the geotechnical cloth are fixed into a whole through the cement mortar. According to the composite pile, the soft soil strength can be improved, and the high strength of the composite pile can be fully utilized.

Description

Technical Field

[0001] This utility model relates to the field of basic engineering construction, specifically to a composite pile structure that first drains water and then reinforces it. Background Technology

[0002] In road construction, embankment fill on soft soil foundations faces problems of slope instability and uneven settlement. Therefore, soft soil foundations are usually treated in various ways. These treatment methods can be broadly categorized into two types: The first type is drainage methods, including the installation of plastic drainage boards and sand-filled bags. This method is relatively inexpensive and can remove moisture from the soft soil, improving its strength and bearing capacity. Its advantage is increased bearing capacity, but its disadvantage is that the drainage itself does not improve the bearing capacity of the foundation. The second type is reinforcement methods, such as cement-mixed piles and CFG piles. These methods fully utilize the strength of the piles, resulting in high pile strength. However, the moisture in the soft soil cannot be drained, and the strength of the surrounding soft soil is not improved. Utility Model Content

[0003] The purpose of this utility model is to provide a composite pile structure that first drains and then reinforces, which can both improve the strength of soft soil and make full use of the high strength of the composite pile.

[0004] The technical solution of this utility model is as follows: a composite pile structure for drainage followed by reinforcement, comprising a geogrid rolled into a cylindrical shape, a layer of geotextile fixed on the inner side of the geogrid, a grouting pipe vertically inserted on the inner side of the geotextile, a plurality of radial through holes spaced apart on the side wall of the grouting pipe, the area enclosed between the outer wall of the grouting pipe and the inner wall of the geotextile and the grouting pipe being filled with gravel, and cement mortar injected after drainage of soft soil being poured into the inner cavity of the grouting pipe, the radial through holes and the gaps between the gravel, and the grouting pipe, gravel and geotextile being fixed together by cement mortar.

[0005] Furthermore, the geogrid is made of polyethylene or polypropylene material.

[0006] Furthermore, the outer diameter of the geogrid is 250mm~350mm, and the thickness of the geogrid is 4mm~7mm.

[0007] Furthermore, the thickness of the geotextile is 0.3mm to 2.5mm.

[0008] Furthermore, the grouting pipe is a PVC pipe.

[0009] Furthermore, the length of the PVC pipe is greater than or equal to the height of the geogrid, and the diameter of the PVC pipe is 100~300mm.

[0010] Furthermore, the radial through holes are spaced apart along the circumferential direction on the sidewall of the grouting pipe, and the sidewall of the grouting pipe is provided with several rings of radial through holes spaced apart from top to bottom.

[0011] Furthermore, the diameter of the radial through hole is 4 mm to 30 mm.

[0012] Furthermore, the cement mortar is injected into the grouting pipe under high pressure using a high-pressure grouting machine.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. This composite pile is suitable for soft soil foundation treatment. It makes full use of the permeability of geotextile and the water conductivity of crushed stone. Under the action of the superstructure load, the water in the soft soil permeates through the geotextile, enters the crushed stone and is discharged to the ground, thereby improving the strength of the soft soil and the bearing capacity of the foundation.

[0015] 2. When the soft soil reaches a certain hardness, high-pressure grouting solidifies the crushed stone, and under the constraint of the geogrid, the resulting composite pile has high strength and bearing capacity. Therefore, this composite pile can both improve the strength of the soft soil and fully utilize the high strength of the composite pile, resulting in high strength and bearing capacity. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] In the diagram: 1-Geogrid 2-Geotextile 3-Gravel 4-PVC pipe 41-Radial through hole 5-Cement mortar. Detailed Implementation

[0018] To make the above-mentioned features and advantages of this utility model more easily understood, specific embodiments are described below in conjunction with the accompanying drawings, but this utility model is not limited thereto.

[0019] refer to Figure 1

[0020] A composite pile structure with drainage followed by reinforcement includes a geogrid 1 placed inside a driven pipe and rolled into a cylindrical shape, a layer of geotextile 2 fixed on the inner side of the geogrid, a grouting pipe 4 vertically inserted on the inner side of the geotextile, a plurality of radial through holes 41 spaced apart on the side wall of the grouting pipe, gravel 3 filling the area enclosed between the outer wall of the grouting pipe and the inner wall of the geotextile, and the grouting pipe itself, and cement mortar 5 injected after drainage of the soft soil filling the gaps between the inner cavity of the grouting pipe, the radial through holes, and the gravel. The grouting pipe, gravel, geotextile, and geogrid are fixed together by cement mortar to form a composite pile.

[0021] In this embodiment, the geogrid is made of polyethylene or polypropylene. By using polyethylene, which has excellent low-temperature resistance and good chemical stability, or polypropylene, which has high impact resistance and strong mechanical properties, it can better adapt to the environment of soft soil foundation.

[0022] In this embodiment, the outer diameter of the geogrid is 250mm~350mm, preferably 300mm. The thickness of the geogrid is 4mm~7mm, preferably 5.5mm. The thickness of the geotextile is 0.3mm~2.5mm, preferably 1.5mm.

[0023] In this embodiment, the grouting pipe is a PVC pipe, which is readily available and inexpensive, thus helping to reduce costs.

[0024] In this embodiment, the length of the PVC pipe is greater than or equal to the height of the geogrid to better inject cement mortar into the gravel within the geotextile layer. The diameter of the PVC pipe is 100~300mm to better match the high-pressure grouting machine.

[0025] In this embodiment, the radial through holes are spaced apart along the circumferential direction on the side wall of the grouting pipe, and the side wall of the grouting pipe is provided with several rings of radial through holes from top to bottom, so that cement mortar can be injected into the gaps of gravel at different heights and locations.

[0026] In this embodiment, the diameter of the radial through hole is 4 mm to 30 mm, preferably 18 mm.

[0027] In this embodiment, the cement mortar is injected into the grouting pipe under high pressure using a high-pressure grouting machine.

[0028] During construction, the first step is to sink the pipe into the soft soil foundation. Then, a geogrid with geotextile fixed to its inner surface is placed inside the pipe. A PVC pipe is then vertically inserted inside the geotextile layer. Crushed stone is poured into the area enclosed between the geotextile and the PVC pipe, as well as into the PVC pipe itself. Once full, the pipe is pulled out. Loads such as embankment fill, concrete blocks, and sandbags are then placed on the soft soil foundation. After the soft soil has drained for a certain period, cement mortar is injected into the PVC pipe using a high-pressure grouting machine. This cement mortar fixes the grouting pipe, crushed stone, geotextile, and geogrid together to form a composite pile. This composite pile not only improves the strength of the soft soil but also fully utilizes the high strength of the composite pile, resulting in high strength and bearing capacity.

[0029] If this utility model discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws) or a non-detachable fixed connection (e.g., riveting or welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral forming process).

[0030] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model above include states or shapes that are similar to, close to, or approximate with them.

[0031] Any component provided by this utility model can be assembled from multiple individual components, or it can be a single component manufactured by a one-piece molding process.

[0032] The above description is only a preferred embodiment of the present utility model. All equivalent changes and modifications made within the scope of the patent application of the present utility model shall be covered by the present utility model.

Claims

1. A pre-drainage and post-reinforcement composite pile structure, characterized by, The geogrid is rolled into a cylinder, a layer of geotextile is fixed on the inner side of the geogrid, a grouting pipe is vertically inserted on the inner side of the geotextile, a plurality of radial through holes are formed in the side wall of the grouting pipe at intervals, the area surrounded by the outer wall of the grouting pipe and the inner wall of the geotextile and the grouting pipe is filled with gravel, the gap between the inner cavity of the grouting pipe, the radial through holes and the gravel is filled with cement mortar injected after the soft soil is drained, and the grouting pipe, the gravel and the geotextile are fixed into an integrated whole by the cement mortar.

2. The pre-drainage and post-reinforcement composite pile structure according to claim 1, characterized in that, The geogrid is made of polyethylene or polypropylene material.

3. The pre-dewatering and post-reinforcing composite pile structure according to claim 1 or 2, characterized in that, The outer diameter of the geogrid is 250 mm-350 mm, and the thickness of the geogrid is 4 mm-7 mm.

4. The pre-drainage and post-reinforcement composite pile structure according to claim 1, characterized in that, The thickness of the geotextile is 0.3 mm-2.5 mm.

5. A pre-drainage and post-reinforcement composite pile structure according to claim 1, 2 or 4, characterized in that, The grouting pipe is a PVC pipe.

6. The pre-drainage and post-reinforcement composite pile structure according to claim 5, characterized in that, The length of the PVC pipe is greater than or equal to the height of the geogrid, and the pipe diameter of the PVC pipe is 150-250 mm.

7. A pre-dewatering and post-reinforcing composite pile structure according to claim 1, 2, 4 or 6, characterized in that, The radial through holes are arranged along the side wall of the grouting pipe at intervals in the circumferential direction, and a plurality of rings of radial through holes are arranged on the side wall of the grouting pipe at intervals from top to bottom.

8. The pre-drainage and post-reinforcement composite pile structure according to claim 7, characterized in that, The diameter of the radial through hole is 4 mm-30 mm.

9. The pre-dewatering and post-reinforcing composite pile structure according to claim 1, characterized in that, The cement mortar is high-pressure injected into the grouting pipe by a high-pressure grouting machine.

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