CN115467322A

CN115467322A - Precast pile grouting after stirring and implanting into pile end and construction method thereof

Info

Publication number: CN115467322A
Application number: CN202110597086.0A
Authority: CN
Inventors: 胡玉银; 陈建兰
Original assignee: Shanghai Tongrenli Geotechnical Engineering Technology Co ltd
Current assignee: Shanghai Tongrenli Geotechnical Engineering Technology Co ltd
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2022-12-13

Abstract

The application discloses a construction method for stirring and implanting a precast pile after pile end grouting, which comprises the following steps: stirring a soil layer of a pile area to a designed elevation of a pile bottom, wherein a curing agent is added into the stirred soil layer of the pile area in the stirring process to form a stirring pile in the pile area; implanting a precast pile provided with a pile-end post-grouting device into the mixing pile, wherein the radial dimension of the precast pile is smaller than that of the mixing pile; performing clear water plugging on the post-pile-end grouting device through a grouting pipe in the precast pile to form a subsequent grouting pipeline; maintaining for a predetermined time after the precast pile is implanted into the mixing pile; and carrying out post grouting on the pile end through the pile end post grouting device so as to reinforce the pile end soil. The application also discloses a stirring implanted pile end post-grouting precast pile formed by the method.

Description

Precast pile prepared by grouting after stirring and implanting into pile end and construction method thereof

Technical Field

The present invention belongs to the field of building engineering. In particular to a mixing pile, a construction method of a precast pile and the formed mixing pile and the precast pile.

Background

The precast pile has the advantages of high construction efficiency, easy quality control and low cost, so the engineering application is very wide. However, the precast pile is a soil-extruding pile, and the construction has a large influence on the environment no matter the pile is sunk by adopting a static pressure or hammering process. Therefore, in the area with higher requirement for environmental protection, the application of the precast pile is limited, and a cast-in-place pile without soil squeezing effect is often used, but in the cast-in-place pile construction process, the quality control is difficult, the construction period is long, the cost is higher, and the slurry discharge has the hidden trouble of environmental protection.

Therefore, engineering technicians develop a technology for embedding the mixing pile into the sinking pile, namely, firstly, a single-shaft mixing pile machine is adopted to mix the soil layer to the designed elevation of the pile bottom, and then the precast pile is embedded into the mixing pile.

In order to improve the bearing performance of the implanted pile of the mixing pile, the currently adopted engineering technical measures are mainly as follows: increase the stake footpath, adopt special equipment to stir in the drilling and expand the end, wherein the cement quantity increases, the pile body adopts prefabricated bamboo joint stake in order to increase the contact force of pile body and soil. These measures increase the construction cost and reduce the cost performance, thereby restricting the popularization and application of the method.

The applicant finds that the bearing performance of the traditional mixing pile implanted precast pile is unsatisfactory, and the key point is that the bearing performance is greatly weakened because a pile end soil layer is disturbed during mixing construction. Therefore, a process that the soil layer at the pile end is disturbed little during stirring construction is needed.

Disclosure of Invention

It is an object of the present application to at least solve the above technical problems and to provide an improved precast pile construction method.

To this end, some embodiments of the present application provide a method of constructing a precast pile by grouting after agitation of an implanted pile end, the method comprising: stirring the soil layer in the pile area to the designed elevation of the pile bottom; adding a curing agent into the stirred soil layer of the pile area in the stirring process to form a stirring pile in the pile area; implanting a precast pile provided with a pile-end post-grouting device into the mixing pile, wherein the radial dimension of the precast pile is smaller than that of the mixing pile; carrying out clear water plugging on the post-grouting device at the pile end through a grouting pipe in the precast pile to form a subsequent grouting pipeline; curing for a predetermined time after the precast pile is implanted into the mixing pile; and carrying out post grouting on the pile end through the pile end post grouting device so as to reinforce the pile end soil.

In some embodiments, the implanting may employ a static pile sinking process.

In some embodiments, the precast pile provided with the grouting device may be a precast pile provided with a post-prestressed pipe pile grouting device, or may be a precast pile provided with a post-prestressed solid square pile grouting device.

In some embodiments, the addition amount of the curing agent is controlled so that the mass content ratio of the curing agent in the stirring pile is 5-25%, for example, 5%, 10%, 15%,20%,25%.

In some embodiments, the adding the curing agent includes dry adding the curing agent and wet adding the curing agent slurry.

In some embodiments, the curing agent is cement.

Still other embodiments of the present application provide a precast pile grouted after the agitation implantation pile end formed by the above method.

In some embodiments, the mixing implant pile tip post-grouting precast pile includes an inner zone portion and an outer zone portion engaged between the inner zone portion and the old soil.

In some embodiments, the radial dimension of the outer zone portion is 1.5, 2, or 3 times the radial dimension of the inner zone portion.

The application provides a stirring is implanted pile end back slip casting precast pile construction method and precast pile who forms has following advantage: (1) construction is green and environment-friendly: the pile belongs to a non-soil-squeezing pile, and has small influence on the surrounding environment; compared with a cast-in-situ bored pile, the discharge of slurry is greatly reduced, and the method is green and environment-friendly. And (2) equipment investment is simple: a conventional single-shaft mixing pile machine and a conventional post-grouting device; no special equipment is required. (3) construction quality is controllable: firstly, the compression-resistant bearing performance of the pile body only utilizes the bearing capacity of the prefabricated pile body without the aid of the strength of cement soil, so that the quality of the pile body is controllable; secondly, the precast pile end post-grouting device and the construction method adopt the technology of ' a prestressed pipe pile post-grouting device and the construction method thereof ' (the patent number is 202010492842.9) ' a prestressed solid square pile post-grouting device and the construction method thereof ' (the patent number is 202110183342.1) ', and the quality is also controllable. (4) has obvious economic benefits: the pile body of the concrete precast pile has the advantage of high bearing performance, and the soil body can be reinforced by grouting through the pile end post-grouting process, so that the bearing performance of the pile foundation is improved, and the cost performance of the pile is higher than that of the traditional static drilling root-planting pile.

Drawings

Fig. 1 is a flow chart of a construction method of stirring a precast pile after being implanted into a pile end and grouting the precast pile according to an embodiment of the present application;

fig. 2 is a stirred implanted pile end post-grouting precast pile obtained by the stirred implanted pile end post-grouting precast pile construction method according to the embodiment of the present application;

fig. 3A to 3E are schematic structural diagrams of a grouting device after a prefabricated solid square pile according to an embodiment of the application.

Detailed Description

Embodiments of the present application will be described below with reference to the drawings.

Specific structural and functional details disclosed herein are merely representative and are provided for purposes of describing example embodiments of the present application. This application may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element may be termed a second element, and, similarly, a second element may be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should also be noted that, in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed substantially concurrently, or the figures may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

The application provides a brand-new construction method, which comprises the steps of firstly forming a mixing pile in a column area, then pressing a precast pile in the range of the mixing pile before the mixing pile is solidified, and after the precast pile is pressed in, carrying out grouting operation on the column area by using a post-grouting device at the pile end of the precast pile, so as to form a desired pile body. The pile body is formed to have a two-layer structure of an inner zone part and an outer zone part which are tightly jointed in the radial direction, wherein the pile body of the outer zone part is formed on the mixing pile, and the pile body of the outer zone part is tightly jointed with the precast pile positioned in the inner zone part on one hand and is tightly jointed with the old soil outside the pile zone on the other hand. The method and the device achieve the purpose of saving cost while ensuring the process quality.

According to an embodiment of the application, the construction method for stirring the precast pile after being implanted into the pile end and grouting the pile end comprises the following steps as shown in figure 1:

step S1: stirring the soil layer in the pile area to a designed elevation of the pile bottom; the stirring can be carried out using a conventional single-shaft stirrer. The step of stirring the soil layer of the pile area comprises adding cement to the stirred soil layer in the stirring process to form a cement-soil stirring pile in the pile area, wherein the cement content is 5% to 25%. The added cement can be determined according to the soil quality of the soil layer in the pile area, for example, dry cement powder can be added in the stirring process for the soil layer in the pile area with higher moisture content, and cement slurry can be added in the stirring process for the soil layer in the pile area with lower moisture content.

Step S2: and implanting the precast pile provided with the grouting device into the cement soil mixing pile. The implantation process can adopt a static pressure pile sinking process; the precast pile with the grouting device installed therein may be a precast pile with a prestressed pipe pile post-grouting device, or a precast pile with a prestressed solid square pile post-grouting device.

The specific structure of the precast pile with the post-grouting device for the prestressed pipe pile can be the precast pile disclosed in the chinese patent application with publication number CN111519618A, which is filed by the applicant and is named as a post-grouting device for the prestressed pipe pile and a construction method thereof. The precast pile provided with the prestressed solid square pile post-grouting device can be No. 2021101833421, which is filed by the applicant and is named as a precast pile disclosed in the precast solid square pile post-grouting device and the construction method thereof. The present application incorporates both of the above-identified applications in their entireties as if fully set forth herein.

In particular, the precast pile used in the present application may be a precast pile including a post-grouting device as described below. As shown in fig. 3A to 3E, the post grouting device includes at least one pile body 2 coaxially arranged from bottom to top, a grouting pipe 21 is arranged inside the pile body, a pile bottom grouting assembly 1 fixedly connected with the pile body is arranged at the bottom end of the lowest pile body, and a pile top grouting assembly 3 detachably connected with the pile body is arranged at the top of the uppermost pile body, wherein the pile bottom grouting assembly 1 includes a first steel sleeve 13, a grouting device 12 located inside the first steel sleeve 13, a first steel sealing plate 11 located at two ends of the first steel sleeve 13, and a steel sleeve sealing plate 15 for sealing the first steel sleeve 13, the first steel sealing plate 11 is connected with the end of the pile body 2, and is provided with a through hole 111 communicated with the grouting pipe and the inside of the first steel sleeve, a plurality of grouting holes are arranged on the pipe wall of the first steel sleeve 13, and the grouting device 12 is communicated with the grouting pipe 21; the pile top grouting assembly 3 comprises a second steel sealing plate 31 and a second steel sleeve 32 arranged on the second steel sealing plate 31, and the second steel sleeve 32 is communicated with the grouting 21 pipe.

The pile bottom grouting assembly 1 further comprises at least one rib plate 14, and the at least one rib plate 14 is connected with the first steel sealing plate 11 and the first steel sleeve 13 along the periphery of the first steel sleeve 13. Wherein, the at least one rib 14 is four, and the corner of each rib 14 has a chamfer. Wherein the inside of the first steel casing 12 is also filled with coarse sand 16 surrounding the grouter 12. The slurry outlet holes are uniformly arranged along the wall of the first steel sleeve 13, and the aperture of each slurry outlet hole is 8-10 mm. Wherein the grouter 12 has a check valve. Wherein, the diameter of the first steel closing plate 11 is larger than that of the first steel sleeve 13.

Step S3 may be started after step S2 is completed. Step S3 includes performing water plugging and unplugging on the pile end grouting device through a grouting pipe in the precast pile, such as the grouting pipe 21 described above, to form a subsequent grouting pipeline.

Step S4 may be started after step S3 is completed. And step S4, curing for 48 hours after the precast pile with the pile body provided with the grouting device is implanted into the mixing pile.

Step S5 may be started after the curing of step S3 is completed. And S5, post-grouting the pile end through the pile end post-grouting device to reinforce the pile end soil so as to finish the manufacturing of the pile body.

As shown in fig. 2, the mixing pile bore diameter is larger than the precast pile diameter so that an outer zone portion 20 is formed radially outside the precast pile, i.e., the outer zone portion 10 of the pile body. The radial dimension of the outer zone portion 20 may for example be 1.5 times, 2 times, 3 times, etc. the radial dimension of the inner zone portion 10. The inner zone portion is preferably disposed coaxially with the outer zone portion. The pile body of the outer zone portion 20 is formed in a mixing pile which is tightly engaged with a prefabricated pile located in the inner zone portion 20 on the one hand and with the old soil 30 outside the pile zone on the other hand, wherein the cement content of the cement soil mixing pile may be any value including end points from 5% to 25% by mass, such as 5%, 10%, 15%,20%,25%.

Taking the 20% incorporation as an example, if one cubic meter of the mixing soil layer, for example, the mass of the soil cement is 1.9 tons, the total amount of cement incorporated is 1.9 × 20% =0.38 tons.

Since the precast pile is formed in the area of the mixing pile, the structure of the old soil on the outer side is not substantially damaged when the precast pile is pressed in. In addition, because the outer zone part where the mixing pile is arranged is provided, the requirements on the components of the grouting of the precast pile are also greatly lower,

the cross-sectional shape of the shaft of the precast pile is not limited, and may be, for example, a circle, a square, or another polygon. There is also no limitation to the precast pile, for example, its cross section may vary longitudinally along the pile body, for example, to form a bamboo joint pile, or may not vary, for example, to be a smooth cylinder. There is no limitation as to whether the precast pile is solid, for example, the pile body may be solid or hollow. The precast pile is provided with a grouting device at the bottom of the pile, and the pile body can be a precast tubular pile, a hollow square pile or a solid square pile. If the pile body is hollow, a grouting pipe needs to be installed in the cavity; if the pile body is solid, the grouting pipe is embedded in the solid pile during the member processing.

Pile end post-grouting precast pile is implanted in the stirring, and the advantage of stake is implanted to present stirring stake lies in: firstly, the requirement on equipment in the aspect of a single-shaft mixing pile construction process is low, a conventional single-shaft mixing pile machine can be implemented, and special equipment for bottom expanding at the pile end is not needed; the amount of the curing agent such as cement mixed into the mixing pile is not high, and the cement soil does not need to be mixed in a specific ratio due to the consideration of the holding force of old soil outside the pile and the pile body, so that the construction quality of the cement soil mixing pile is easy to control. Secondly, in the aspect of construction process: although the grouting step after pile sinking is added, the whole construction efficiency of the implanted pile is not influenced, and the post grouting can be operated in a flow mode.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Moreover, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the present disclosure and associated techniques may include other embodiments not explicitly shown or described herein. Accordingly, the disclosure is limited only by the following claims.

Claims

1. A construction method for grouting a precast pile after stirring and implanting into a pile end is characterized in that: the method comprises the following steps: stirring a soil layer of a pile area to a designed elevation of a pile bottom, wherein a curing agent is added into the stirred soil layer of the pile area in the stirring process to form a stirring pile in the pile area; implanting a precast pile provided with a pile-end post-grouting device into the mixing pile, wherein the radial dimension of the precast pile is smaller than that of the mixing pile; performing clear water plugging on the post-pile-end grouting device through a grouting pipe in the precast pile to form a subsequent grouting pipeline; maintaining for a predetermined time after the precast pile is implanted into the mixing pile; and post-grouting the pile end through the pile end post-grouting device to reinforce the pile end soil.

2. The construction method of the precast pile by stirring and grouting after the pile is implanted into the pile end according to claim 1, characterized in that: the implantation process adopts a static pressure pile sinking process.

3. The construction method of the stirring-implanted pile-end post-grouting precast pile according to claim 1, characterized in that: the precast pile provided with the grouting device is a precast pile provided with a prestressed pipe pile rear grouting device, or a precast pile provided with a prestressed solid square pile rear grouting device.

4. The construction method of the stirring-implanted pile-end post-grouting precast pile according to claim 1, characterized in that: the adding amount of the curing agent is controlled so that the mass content proportion of the curing agent in the stirring pile is 5-25%.

5. The construction method of the precast pile by stirring and grouting after the pile is implanted into the pile end according to claim 4, characterized in that: the mass content of the curing agent of the stirring pile is 5%, 10%, 15%,20% and 25%.

6. The construction method of the stirring-implanted pile-end post-grouting precast pile according to claim 1, characterized in that: the addition of the curing agent comprises dry powder adding of the curing agent by a dry method and slurry adding of the curing agent by a wet method.

7. The construction method of the precast pile by stirring and grouting after the pile is implanted into the pile end according to claim 1, characterized in that: the curing agent is cement.

8. The precast pile after stirring implantation at the pile end formed by the construction method of the precast pile after stirring implantation at the pile end according to any one of claims 1 to 7.

9. The stirring-embedded pile-end post-grouting precast pile according to claim 8, characterized in that: the stirring implantation pile end post-grouting precast pile comprises an inner zone part and an outer zone part which is jointed between the inner zone part and old soil.

10. The stirring pile-end-implanted grouting precast pile according to claim 9, characterized in that: the radial dimension of the outer zone portion is 1.5, 2 or 3 times the radial dimension of the inner zone portion.