Integrated construction method for pile body and pile cap of CFG pile

Abstract

According to the pile body and pile cap integrated construction method for the CFG pile, a CFG pile cap foundation pit is formed on the surface layer of a foundation in advance through a pile cap gravity former at the pile position of the CFG pile of a medium-compressibility soil foundation; a pile cap hole model device is arranged in a pile cap foundation pit, so that the stability of the pile cap foundation pit in the CFG pile construction process is guaranteed, unearthed soil is convenient to clean during construction of a long spiral drilling machine, and when the CFG pile long spiral drilling machine lifts and pours concrete to the bottom elevation of a CFG pile cap, the pile cap hole model device and a drilling rod of the long spiral drilling machine lift synchronously; the CFG pile body and the pile cap concrete are formed at a time to form an integral structure; according to the construction method, existing CFG pile construction equipment can be fully utilized, operation is easy, quality is easy to control, economical efficiency is good, the construction period is short, the construction method can be suitable for construction of pile caps of all sizes, limitation of the construction equipment is avoided, the environment-friendly requirement is met, and application and popularization are facilitated.

Description

Technical Field

[0001] The invention relates to geotechnical engineering, and in particular to a pile body and pile cap integrated construction method for a CFG pile. Background Art

[0002] Medium compressibility soil refers to compression coefficient a=0.1-0.5MPa -1 Most of the foundation soil in my country belongs to the category of medium compressible soil. When constructing a high-speed railway subgrade project on a medium compressible soil foundation, since the deformation control standard of the high-speed railway subgrade is at the millimeter level, it is usually necessary to reinforce the medium compressible soil foundation. CFG piles are the most widely used composite foundation reinforcement measures for medium compressible soil foundations, with good economy and easy quality control. In order to effectively exert the reinforcement effect of CFG piles, a pile cap structure is usually set on the top of the CFG pile. In actual engineering, the CFG pile cap can only be constructed after the CFG pile construction is completed and reaches the design strength. The CFG pile head is cut off and the pile cap foundation pit is excavated for secondary pile cap construction. For example, the patent with application number 201811398078.8 proposes a construction method of cutting the pile head before CFG pile and casting the pile cap with soil mold. In both cases, the pile cap construction is carried out after the pile body construction is completed and reaches the design strength, that is, the pile cap and the CFG pile body are secondary molded. There are the following problems: (1) The CFG pile and the pile cap are secondary molded, and the maintenance time of the CFG pile body and the pile cap is directly superimposed, which has a long construction period; (2) After the CFG pile reaches the design strength, the excavation of the pile cap foundation pit has large interference, low efficiency, and irregular shape of the pile cap foundation pit; (3) The CFG pile body and the pile cap are secondary molded, the structural integrity is poor, and the pile cap is prone to tilting under the action of upper fill and mechanical equipment. At present, there are also some improved mechanical equipment that can realize the integrated construction of CFG pile body and pile cap, but they are special equipment with complex equipment structure, high cost and high operation technology requirements, and cannot effectively utilize a large number of existing CFG pile construction equipment. Therefore, it is of great significance to propose a CFG pile body and pile cap integrated construction method, which has the characteristics of making full use of existing CFG pile construction equipment, simple operation, easy quality control, good economy, short construction period, etc., and meets environmental protection requirements and is conducive to promotion and application. Summary of the invention

[0003] 1. Technical issues to be resolved The technical problem to be solved by the present invention is to provide a pile body and pile cap integrated construction method for CFG piles, so as to make full use of existing CFG pile construction equipment and realize the pile body and pile cap integrated construction of CFG piles quickly and economically.

[0004] (II) Technical solution To achieve the above object, the present invention provides the following technical solutions: A pile body and pile cap integrated construction method for a CFG pile comprises the following steps: A. Ground leveling and CFG pile (3) pile position plane positioning; B. Using a pile cap gravity former (1) at the CFG pile structure (3), the pile cap gravity former (1) is pressed into the surface layer of the medium compressible soil foundation by static pressure or hammering. When the top of the pile cap gravity former (1) is flush with the foundation, the pressing is stopped; C. Lift out the pile cap gravity former (1) by means of a crane; D. hoisting a pile cap hole model (2) into a foundation pit of a CFG pile cap (31) formed on the ground; E. The long spiral drill rod passes through the hole in the middle of the pile cap hole model (2) to carry out long spiral drilling construction of the CFG pile structure (3). The drilling rig is unearthed and cleaned at the top of the pile cap hole model (2) until the designed bottom elevation of the CFG pile structure (3) is reached; F. Slowly lift the CFG pile (3) long screw drill and simultaneously pour concrete into the CFG pile structure (3) through the concrete pouring hole in the middle of the long screw drill; G. When the long spiral drill is lifted to the bottom elevation of the pile cap hole model (2), the pile cap hole model (2) is connected to the drill rod of the long spiral drill and is lifted synchronously and slowly, with the lifting speed being slower than the lifting speed of the CFG pile body (32); H. Stop concrete pouring construction until the concrete pouring of the CFG pile cap (31) structure space is completely completed; I. The concrete structure of the CFG pile structure (3) is cured to the designed strength, and the top of the CFG pile cap (31) is cut and leveled.

[0005] Preferably, the pile cap gravity former (1) is composed of a middle gravity forming body (11), a bottom cap tip fixer (12), and an upper center lifting ring (13), which can be pressed into the foundation soil by static pressure and hammering to form a CFG pile cap foundation pit. The pile cap hole is formed quickly and regularly by the gravity former (1), which has a compacting effect on the foundation soil.

[0006] Preferably, the gravity-formed body (11) can be a steel structure or a prefabricated reinforced concrete structure, which is heavy and easy to be pressed into the foundation soil. The structural dimensions are adjustable and not affected by construction machinery. The structural diameter and chamfer are required to match the dimensions of the CFG pile cap.

[0007] Preferably, a cap tip holder (12) is provided at the bottom of the gravity-formed body (11) to facilitate rapid and accurate vertical positioning of the gravity-formed body (11) and enhance planar stability, and a large-diameter steel bar structure may be used.

[0008] Preferably, a central lifting ring (13) is provided on the top of the gravity-formed body (11) to facilitate lifting and movement of the structure.

[0009] Preferably, the chamfer of the gravity-formed body (11) at the variable cross-section is consistent with that of the CFG pile cap, and generally β is 120°-140°.

[0010] Preferably, the pile cap hole model (2) is composed of a model body (21), a long spiral drill rod through hole (22), and a side lifting ring (23). The pile cap hole model (2) is placed in a CFG pile cap foundation pit, which can ensure the stability of the pile cap foundation pit and enable the CFG pile long spiral drill to be excavated directly at the ground level during construction, which is convenient for excavation and cleaning.

[0011] Preferably, the model body (21) is a pile cap foundation pit force-supporting structure, and a composite light structure can be used, so that it is convenient to directly connect and lift it with a long spiral drill rod in the later stage; Preferably, the long spiral drill rod passage hole (22) is a passage for the drill rod to pass during CFG pile construction; Preferably, the side lifting ring (23) is convenient for being placed in the pile cap foundation pit and directly connected to the long spiral drill rod at a later stage; Preferably, the size of the model body (21) is consistent with that of the pile cap, the chamfer at the variable cross-section is consistent with that of the CFG pile cap, and the pile cap collapse height L is generally 0.5-0.1 m.

[0012] (III) Beneficial effects The beneficial effects of the present invention are that, at the position of the CFG pile in the medium compressible soil foundation, the CFG pile cap foundation pit is formed in advance on the surface of the foundation by the pile cap gravity former, and a pile cap hole model is set in the pile cap foundation pit to ensure the stability of the pile cap foundation pit during the CFG pile construction process and facilitate the excavation and cleaning during the construction of the long spiral drill. When the CFG pile long spiral drill lifts the poured concrete to the bottom elevation of the CFG pile cap, the pile cap hole model is synchronously lifted with the long spiral drill drill rod, and the CFG pile body and the pile cap concrete are formed at one time to form an integral structure; the pile cap gravity former is used to form the CFG pile cap foundation pit in the foundation through the gravity pressing type of non-excavation soil extraction, and the foundation pit is formed by squeezing and compacting soil, which has a higher bearing capacity, and the bearing performance of the CFG pile is better after it is formed. The proposed construction method can make full use of the existing CFG pile construction equipment, is simple to operate, easy to control quality, good economy, and short construction period. It can be applied to pile cap construction of all sizes, is not limited by construction equipment, meets environmental protection requirements, and is conducive to popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of a pile cap gravity former of a pile body and pile cap integrated construction method of a CFG pile of the present invention.

[0014] Figure 2 The present invention is a cross-sectional schematic diagram of a pile cap hole model device for a pile body and pile cap integrated construction method of a CFG pile.

[0015] Figure 3 The present invention is a plan view of a pile cap hole modeler of a pile body and pile cap integrated construction method of a CFG pile.

[0016] Figure 4 The present invention is a schematic diagram of a pile cap and pile body formed CFG pile structure of a pile body and pile cap integrated construction method of a CFG pile.

[0017] Markings in the figure: 1-pile cap gravity former; 11-gravity former body; 12-cap tip fixer; 13-center lifting ring; 2-pile cap hole modeler; 21-model body; 22-long spiral drill rod through hole; 23-side lifting ring; 3-CFG pile structure; 31-CFG pile cap; 32-CFG pile body; W-pile cap top width; D-pile cap height; d-pile body diameter; β-pile cap chamfer; L-pile cap collapse height. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-4 A pile body and pile cap integrated construction method of a CFG pile comprises the following steps: A. Ground leveling and CFG pile (3) pile position plane positioning; B. Using a pile cap gravity former (1) at the CFG pile structure (3), the pile cap gravity former (1) is pressed into the surface layer of the medium compressible soil foundation by static pressure or hammering. When the top of the pile cap gravity former (1) is flush with the foundation, the pressing is stopped; C. Lift out the pile cap gravity former (1) by means of a crane; D. hoisting a pile cap hole model (2) into a foundation pit of a CFG pile cap (31) formed on the ground; E. The long spiral drill rod passes through the hole in the middle of the pile cap hole model (2) to carry out long spiral drilling construction of the CFG pile structure (3). The drilling rig is unearthed and cleaned at the top of the pile cap hole model (2) until the designed bottom elevation of the CFG pile structure (3) is reached; F. Slowly lift the CFG pile (3) long screw drill and simultaneously pour concrete into the CFG pile structure (3) through the concrete pouring hole in the middle of the long screw drill; G. When the long spiral drill is lifted to the bottom elevation of the pile cap hole model (2), the pile cap hole model (2) is connected to the drill rod of the long spiral drill and is lifted synchronously and slowly, with the lifting speed being slower than the lifting speed of the CFG pile body (32); H. Stop concrete pouring construction until the concrete pouring of the CFG pile cap (31) structure space is completely completed; I. The concrete structure of the CFG pile structure (3) is cured to the designed strength, and the top of the CFG pile cap (31) is cut and leveled.

[0020] Preferably, the pile cap gravity former (1) is composed of a middle gravity forming body (11), a bottom cap tip fixer (12), and an upper center lifting ring (13), which can be pressed into the foundation soil by static pressure and hammering to form a CFG pile cap foundation pit. The pile cap hole is formed quickly and regularly by the gravity former (1), which has a compacting effect on the foundation soil.

[0021] Preferably, the gravity-formed body (11) can be a steel structure or a prefabricated reinforced concrete structure, which is heavy and easy to be pressed into the foundation soil. The structural dimensions are adjustable and not affected by construction machinery. The structural diameter and chamfer are required to match the dimensions of the CFG pile cap.

[0022] Preferably, a cap tip holder (12) is provided at the bottom of the gravity-formed body (11) to facilitate rapid and accurate vertical positioning of the gravity-formed body (11) and enhance planar stability, and a large-diameter steel bar structure may be used.

[0023] Preferably, a central lifting ring (13) is provided on the top of the gravity-formed body (11) to facilitate lifting and movement of the structure.

[0024] Preferably, the chamfer of the gravity-formed body (11) at the variable cross-section is consistent with that of the CFG pile cap, and generally β is 120°-140°.

[0025] Preferably, the pile cap hole model (2) is composed of a model body (21), a long spiral drill rod through hole (22), and a side lifting ring (23). The pile cap hole model (2) is placed in a CFG pile cap foundation pit, which can ensure the stability of the pile cap foundation pit and enable the CFG pile long spiral drill to be excavated directly at the ground level during construction, which is convenient for excavation and cleaning.

[0026] Preferably, the model body (21) is a pile cap foundation pit force-supporting structure, and a composite light structure can be used, so that it is convenient to directly connect and lift it with a long spiral drill rod in the later stage; Preferably, the long spiral drill rod passage hole (22) is a passage for the drill rod to pass during CFG pile construction; Preferably, the side lifting ring (23) is convenient for being placed in the pile cap foundation pit and directly connected to the long spiral drill rod at a later stage; Preferably, the size of the model body (21) is consistent with that of the pile cap, the chamfer at the variable cross-section is consistent with that of the CFG pile cap, and the pile cap collapse height L is generally 0.5-0.1 m.

[0027] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0028] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0029] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pile body and pile cap integrated construction method for a CFG pile, characterized in that: Here are the steps: A. Ground leveling and CFG pile (3) pile position plane positioning; B. Using a pile cap gravity former (1) at the CFG pile structure (3), the pile cap gravity former (1) is pressed into the surface layer of the medium compressible soil foundation by static pressure or hammering. When the top of the pile cap gravity former (1) is flush with the foundation, the pressing is stopped; C. Lift out the pile cap gravity former (1) by means of a crane; D. hoisting a pile cap hole model (2) into a foundation pit of a CFG pile cap (31) formed on the ground; E. The long spiral drill rod passes through the hole in the middle of the pile cap hole model (2) to carry out long spiral drilling construction of the CFG pile structure (3). The drilling rig is unearthed and cleaned at the top of the pile cap hole model (2) until the designed bottom elevation of the CFG pile structure (3) is reached; F. Slowly lift the CFG pile (3) long screw drill and simultaneously pour concrete into the CFG pile structure (3) through the concrete pouring hole in the middle of the long screw drill; G. When the long spiral drill is lifted to the bottom elevation of the pile cap hole model (2), the pile cap hole model (2) is connected to the drill rod of the long spiral drill and is lifted synchronously and slowly, with the lifting speed being slower than the lifting speed of the CFG pile body (32); H. Stop concrete pouring construction until the concrete pouring of the CFG pile cap (31) structure space is completely completed; I. The concrete structure of the CFG pile structure (3) is cured to the designed strength, and the top of the CFG pile cap (31) is cut and leveled.

2. The method for integrating the pile body and pile cap of a CFG pile according to claim 1, characterized in that: The pile cap gravity former (1) is composed of a middle gravity forming body (11), a bottom cap tip fixer (12), and an upper center lifting ring (13). The pile cap gravity former (1) can be pressed into the foundation soil by static pressure and hammering to form a CFG pile cap foundation pit. The pile cap hole is formed quickly and regularly by the gravity former (1), which has a compacting effect on the foundation soil.

3. The method for integrating the pile body and pile cap of a CFG pile according to claim 2, characterized in that: The gravity-formed main body (11) can be a steel structure or a prefabricated reinforced concrete structure. It is heavy and easy to be pressed into the foundation soil. The structural dimensions are adjustable and not affected by construction machinery. The structural diameter and chamfer are required to match the dimensions of the CFG pile cap.

4. The method for constructing a pile body and pile cap integrated with a CFG pile according to claim 2, characterized in that: The provision of a cap tip holder (12) at the bottom of the gravity-formed main body (11) can facilitate rapid and accurate vertical positioning of the gravity-formed main body (11) and enhance plane stability, and a large-diameter steel bar structure can be used.

5. The method for integrating the pile body and pile cap of a CFG pile according to claim 2, characterized in that: A central lifting ring (13) is provided on the top of the gravity-formed body (11) to facilitate lifting and moving of the structure.

6. The method for constructing a pile body and pile cap integrated with a CFG pile according to claim 2, characterized in that: The chamfer of the gravity-formed body (11) at the variable cross-section is consistent with the CFG pile cap, and generally β is 120°-140°.

7. The method for integrating the pile body and pile cap of a CFG pile according to claim 1, characterized in that: The pile cap hole model (2) is composed of a model body (21), a long spiral drill rod through hole (22), and a side lifting ring (23). The pile cap hole model (2) is placed in a CFG pile cap foundation pit to ensure the stability of the pile cap foundation pit and enable the CFG pile long spiral drill to be excavated directly at the ground level during construction, which is convenient for excavation and cleaning.

8. The method for constructing a pile body and pile cap integrated with a CFG pile according to claim 7, characterized in that: The model body (21) is a force-bearing support structure of the pile cap foundation pit, and a composite light structure can be used, so that a long spiral drill rod can be directly connected and lifted later; the long spiral drill rod through hole (22) is a drill rod through channel during CFG pile construction; and the side lifting ring (23) is convenient for being placed in the pile cap foundation pit and being directly connected to the long spiral drill rod later.

9. The method for constructing a pile body and pile cap integrated with a CFG pile according to claim 7, characterized in that: The size of the model body (21) is consistent with the size of the pile cap, the chamfer at the variable cross-section is consistent with the CFG pile cap, and the pile cap inversion height L is generally 0.5-0.1m.

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