Pile tip assembly for bladder grouting expansion and construction method therefor

Abstract

A pile tip assembly for bladder grouting expansion, comprising a bladder (4), a grouting pipe (2) and a pile tip (3), wherein one end of the grouting pipe (2) is inserted into a prefabricated hollow pile (1), and the other end of the grouting pipe (2) is fixed to the pile tip (3); the bladder (4) is sleeved over the grouting pipe (2), and the bladder (4) is located between the prefabricated hollow pile (1) and the pile tip (3); and a plurality of grout outlet holes are provided in the surface of the grouting pipe (2) located in the bladder (4). By using a principle of pressure grouting, a pile end is expanded and a soil layer at the pile end is compacted at the same time, thereby greatly improving the compressive and uplift bearing capacities of the pile end, and reducing pile settlement.

Description

Soft bag grouting expansion complete pile tip and construction method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of building structures, and in particular to a soft bag grouting expansion complete pile tip and a construction method thereof. BACKGROUND

[0002] The post-grouting technology for precast piles is a technology developed in recent years, which uses the cavity in the middle of a precast hollow pile (tubular pile or hollow square pile) and a pre-embedded grouting pipe to greatly improve the bearing capacity of the pile end and the soil layer near the pile end, thereby greatly improving the single pile bearing capacity and reducing pile foundation settlement, but has the shortcomings of difficult grouting quality control and long construction time.

[0003] In order to reduce the settlement problem of the precast hollow pile, the existing technology uses the precast hollow pile inner ramming carrier pile technology to improve the single pile bearing capacity and reduce the pile foundation settlement, but the construction of the carrier is slow, noisy, and each pile needs to be rammed 200-300 times, and the construction time of each carrier is about 2 hours, which requires more working hours. SUMMARY

[0004] The purpose of the present application is to provide a soft bag grouting expansion complete pile tip and a construction method thereof for improving the pile end bearing capacity by grouting expansion and reducing the construction difficulty.

[0005] To achieve the above purpose, the present application provides a soft bag grouting expansion complete pile tip, which comprises a soft bag, a grouting pipe and a pile tip.

[0006] One end of the grouting pipe is inserted into the precast hollow pile, and the other end of the grouting pipe is fixed with the pile tip.

[0007] The soft bag is sleeved on the grouting pipe, and the soft bag is located between the precast hollow pile and the pile tip; the surface of the grouting pipe in the soft bag is uniformly provided with a plurality of grouting holes.

[0008] Further, the two ends of the soft bag are fixed with the grouting pipe by a lock, and the fixing method is simple.

[0009] Further, the grouting pipe is arranged along the axial direction of the precast hollow pile.

[0010] Further, the pile tip comprises a bottom plate and a cross-shaped pile tip located at the bottom of the bottom plate.

[0011] Further, the soft bag is wrapped with a protective sleeve in a mesh weave.

[0012] The application also provides a construction method of the complete pile tip expanded by soft bag grouting, when the pile tip enters the bearing layer, the high-pressure grouting device is used to inject the slurry from the grouting pipe at the top of the pile to the bottom of the pile at a stable pressure, speed and amount, the slurry is filled into the soft bag, when the internal pressure reaches the critical value, the protective sleeve is expanded, the mortar is pushed to expand the soft bag rapidly, so that the enlarged pile head is formed.

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

[0014] 1. The application uses the pressure grouting principle to expand the pile end and compact the soil layer at the pile end, so that the compression and uplift bearing capacity of the pile end is greatly improved, and the pile settlement is reduced.

[0015] 2. The complete pile tip structure of the application is simple, the grouting holes are arranged at equal intervals on the grouting pipe in the soft bag, so that the internal grouting of the soft bag is uniformly distributed, the tightness of the internal grouting of the expanded soft bag is ensured, and the precast pile can be used for a long time.

[0016] 3. The overall structure is compact, the soft bag is contracted and closely attached to the grouting pipe before grouting expansion, the occupied space is effectively reduced, and transportation is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a schematic view of the soft bag grouting expansion state of the complete pile tip in the embodiment of the application;

[0018] Fig. 2 is a sectional view of the complete pile tip before grouting in the embodiment of the application;

[0019] Fig. 3 is a schematic view of the state that the soft bag is wrapped before grouting in the embodiment of the application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme of the application will be further described below.

[0021] The application provides a complete pile tip expanded by soft bag grouting, as shown in Fig. 1, which is composed of a soft bag 4, a grouting pipe 2 and a pile tip 3.

[0022] The one end of the grouting pipe 2 is inserted into the pile along the axial direction of the precast hollow pile 1, the other end of the grouting pipe 2 is fixed with the pile tip 3;

[0023] The soft bag 4 is sleeved on the grouting pipe 2, and the soft bag 4 is located between the precast hollow pile 1 and the pile tip 3; in this embodiment, the soft bag 4 is made of rubber which has corrosion resistance and good elasticity, and in actual application, nylon, polyester fiber, polyurethane, poly peptide ammonia fabric, polyamide, rubber and other materials can also be used. As shown in Fig. 2, the surface of the grouting pipe 2 located in the soft bag 4 is uniformly provided with a plurality of grouting holes; the arrangement of the plurality of grouting holes can ensure that the grouting in each part of the soft bag 4 is uniform, so as to ensure the tightness of the internal grouting of the soft bag 4.

[0024] In the embodiment, as shown in Fig. 2, the two ends of the soft bag 4 are fixed with the grouting pipe 2 by the lock 42, and the fixing mode is simple and firm.

[0025] In the embodiment, the pile tip 3 is composed of a bottom plate and a cross-shaped pile tip 3 at the bottom of the bottom plate, and the bottom plate is designed to improve the uplift bearing capacity between the pile tip and the foundation in addition to the connection function, and the cross-shaped pile tip 3 can improve the stability of the pile tip 3 in the embedding stage.

[0026] In the embodiment, as shown in Fig. 3, the complete pile tip is wrapped with a protective sleeve 41 in a net-like braid before installation, and the protective sleeve 41 wraps the soft bag 4 on the surface of the grouting pipe 2, so as to avoid the soft bag 4 from loosening and diffusing before grouting expansion, and reduce the space occupation of the soft bag 4 in the transportation stage. At the same time, the protective sleeve 41 also avoids the soft bag 4 from being damaged in the transportation stage. The protective sleeve 41 can be a woven material with certain protective effect, such as nylon, polyester fiber, polyurethane, poly peptide ammonia fabric, etc. In the embodiment, the protective sleeve 41 is nylon, and the woven structure of the protective sleeve 41 can be easily expanded due to the pressure of grouting in the grouting stage.

[0027] The working principle of the complete pile tip is as follows: when the pile tip 3 enters the bearing layer, the high-pressure grouting device is used to inject the slurry from the grouting pipe 2 at the top of the pile to the bottom of the pile at a stable pressure, speed and amount, and the slurry is filled into the soft bag 4. When the internal pressure reaches the critical value, the protective sleeve 41 is expanded, the mortar is pushed to expand the soft bag 4, and the pile end expansion head is formed.

[0028] The above is only the preferred embodiment of the present application, and does not limit the present application in any way. Any person skilled in the art can make any form of equivalent replacement, modification or change to the technical solutions and technical contents disclosed in the present application without departing from the scope of the technical solutions of the present application, and such changes still belong to the protection scope of the present application.

Claims

1. A complete set of pile tips with soft-bladder grouting expansion, characterized in that, Includes soft bladder, grouting pipe, and pile tip; One end of the grouting pipe is inserted into the precast hollow pile, and the other end of the grouting pipe is fixed to the pile tip; The soft bladder is fitted onto the grouting pipe, and the soft bladder is located between the precast hollow pile and the pile tip; the surface of the grouting pipe located inside the soft bladder is uniformly provided with multiple grout outlet holes.

2. The complete set of pile tips with soft-cell grouting expansion according to claim 1, characterized in that, The two ends of the soft bladder are fixed to the grouting pipe by buckles.

3. The complete set of pile tips with soft-cell grouting expansion according to claim 1, characterized in that, The grouting pipe is arranged along the axial direction of the precast hollow pile.

4. The complete set of pile tips with soft-cell grouting expansion according to claim 1, characterized in that, The pile tip includes a base plate and a cross-shaped pile tip located at the bottom of the base plate.

5. The complete set of pile tips with soft-cell grouting expansion according to claim 1, characterized in that, The soft capsule is wrapped with a protective sheath that is woven in a mesh pattern.

6. A construction method for a complete set of soft-cell grouting expanded pile tips, using the complete set of soft-cell grouting expanded pile tips as described in any one of claims 1-5, characterized in that, After the pile tip enters the bearing layer, a high-pressure grouting device is used to inject grout from the grouting pipe at the top of the pile to the bottom of the pile at a steady pressure, speed and volume. The grout is injected into the soft bladder. When the internal pressure reaches the critical value, the protective sleeve is opened, pushing the mortar to quickly expand the soft bladder, thereby forming an enlarged head at the pile end.

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