WO2021190044A1

WO2021190044A1 - Composite lightweight pile structure, manufacturing method, construction method and pile connecting method

Info

Publication number: WO2021190044A1
Application number: PCT/CN2020/141006
Authority: WO
Inventors: 陈伟志; 蒋关鲁; 李安洪; 郭在旭; 姚裕春; 闵圣捷; 曾永红
Original assignee: 中铁二院工程集团有限责任公司
Priority date: 2020-03-23
Filing date: 2020-12-29
Publication date: 2021-09-30
Also published as: CN111395312A

Abstract

Disclosed are a composite lightweight pile structure, a manufacturing method, a construction method and a pile connecting method. The composite lightweight pile structure comprises lightweight soil and a composite reinforcement cage. The composite reinforcement cage comprises vertical geogrids arranged at intervals in the circumferential direction and annular geogrids arranged at intervals in the vertical direction. The lightweight soil material is low in density and high in compression resistance, and the composite reinforcement cage utilizes the tensile capacity of the geogrids to have the effect of a stirrup under the action of a pile top load so that a pile body has higher compression-resistance capacity, and pile collapse or pile breaking is avoided. Meanwhile, the composite reinforcement cage can prevent a composite lightweight pile from cracking, and the structure reduces foundation in-situ effective stress by replacing foundation rock soil. The cage can be used for balancing an overlying load so as to reduce additional stress from the overlying load in a foundation. The structure is high in compression-resistance strength, and the foundation can be reinforced. The bearing capacity of the foundation is improved, and the overlying load can, by means of the structure, be transmitted to a rock-soil stratum which is well laid. The additional stress of an existing building is prevented from increasing, and the purpose of controlling foundation deformation is achieved.

Description

Composite lightweight pile structure, manufacturing method, construction method and pile connection method

Technical field

The invention relates to the technical field of geotechnical engineering, in particular to a composite lightweight pile structure, a manufacturing method, a construction method and a pile connection method.

Background technique

In recent years, with the rapid development of engineering construction, the interrelationships between newly built (structures) and existing buildings or structures include close proximity, upper span, and lower penetration. Under the additional load of newly-built (structures), existing buildings or structures may have uneven settlement, tilt instability, collapse and fracturing, and even cause major safety accidents. In order to meet the requirements of foundation bearing capacity, a large number of pile foundations are often used to reinforce the foundations of newly-built (structures). Such pile foundations replace the original rock and soil. To a certain extent, the additional load of the foundation is increased. Through the transmission of the rock-soil contact force, this additional load may be transmitted to the base of the existing building or structure, plus the load of the overlying new (structure) building, and the additional load of the existing building or structure As the stress increases, the foundation will also be deformed accordingly, and the foundation of existing buildings or structures may be tilted and unstable, thereby affecting the normal use of existing buildings or structures. On the other hand, if the pile foundation construction time of a newly-built (structure) is too long, it may also affect the normal use of existing buildings or structures and increase engineering risks. For this reason, the newly-built (structure) should be adopted as much as possible Prefabricated structure.

Summary of the invention

The purpose of the present invention is to provide a composite lightweight pile structure, a manufacturing method, a construction method and a pile connection method in view of the above-mentioned problems existing in the prior art.

In order to achieve the above objectives, the technical solutions adopted by the present invention are as follows:

Composite lightweight pile structure, including lightweight soil and composite reinforced cage, the composite reinforced cage is buried in the lightweight soil;

The composite reinforced cage includes vertical geogrids arranged at intervals along the circumferential direction and annular geogrids arranged at intervals along the vertical direction. A quadrilateral mesh is formed between the grid and two adjacent annular geogrids.

Through the above structure, the lightweight soil material has light weight, low density and good compressive capacity, and can be constructed and poured in a small space. Compared with other types of lightweight materials, it has better durability, no pollution to the environment, and Excellent environmental protection characteristics, and can significantly reduce the stress of the basement, and control the settlement after construction; the composite reinforced cage utilizes the tensile capacity of the geogrid, and the annular geogrid acts as a stirrup under the load of the pile top, making the pile body It can provide higher compressive capacity to avoid pile collapse or broken piles. At the same time, the composite reinforced cage can play a role as a reinforcement to prevent the composite lightweight pile from cracking. The pile-forming lightweight soil is combined with the composite reinforced cage to obtain Composite lightweight pile structure. This structure reduces the in-situ effective stress of the foundation by replacing the rock and soil of the foundation. It can be used to balance the overburden load to reduce the additional stress of the overburden load in the foundation; secondly, the structure has high compressive strength and can effectively reinforce the foundation. , To significantly improve the bearing capacity of the foundation, the structure can also transmit the overlying load to the underlying rock and soil layer, avoid the increase of the additional stress of the existing buildings or structures, and realize the control of the deformation of the foundations of the existing buildings or structures. The purpose is to shorten the construction time and reduce the engineering risk at the same time.

The manufacturing method of composite lightweight pile is used to manufacture the above-mentioned composite lightweight pile structure, and the manufacturing tool includes the following steps:

S1: Erect the protective pipe in sections from bottom to top;

S2: Send the composite stiffened cage into the protective tube;

S3: Pour light soil into the protective pipe until the light soil fills the protective pipe;

S4: Remove the protective tube in sections.

The manufacturing method ensures the effective realization of the structural function of the composite lightweight pile, with clear flow, simple operation and environmental protection.

As a preferred solution of the present invention, the protective tube is a half-open type, a bracket and a ring hoop are arranged on the protective tube, the annular hoop is locked at the erection position of each protective tube, and the bracket is laid on the outside of each protective tube. Through the above structure, the bracket provides supporting force, and the annular hoop locks the two adjacent protective pipes together.

The term "half-open" means that the protective tube is formed by circumferentially splicing two segments whose arcs are 360°. As a preferred solution of the present invention, in step S2, a weight is provided at the lower part of the composite stiffened cage. Through the above mechanism, the heavy hammer can increase the accuracy of the verticality of the composite stiffened cage and ensure the vertical verticality of the composite stiffened cage.

As a preferred solution of the present invention, in step S2, the upper end of the composite stiffened cage is sleeved into the outer wall of the outlet end of the pumping pipe and locked with an annular lock.

The construction method of composite light-weight pile, used for constructing the above-mentioned composite light-weight pile structure, includes the following steps:

A1: Form foundation drilling;

A2: Put the composite lightweight pile into the foundation borehole, and the upper and lower sections of the composite lightweight pile are connected by connecting piles;

Specifically, the pile connection method adopted by the composite lightweight pile at the upper and lower ends includes the following steps:

B1: Arrange and drill holes at the top of the lower composite lightweight pile and the bottom of the upper composite lightweight pile;

B2: After the lower composite lightweight pile is put into the foundation for drilling, insert connecting steel bars and grouting into the hole on the top of the pile;

B3: The hole position at the bottom of the upper composite lightweight pile is aligned with the pile top connecting steel bars implanted in the lower composite lightweight pile;

B4: The connection between the upper and lower composite light-weight piles shall be wrapped and fixed with a ring plate, and the composite light-weight pile shall be placed in the foundation borehole;

A3: Pour cement mortar along the side of the composite lightweight pile to the top of the pile.

The construction method realizes factory prefabrication, assembly operation and mechanized construction. The pile connection method is used to connect the composite lightweight pile structure, which ensures the effective realization of the composite lightweight pile function and is easy to operate.

As a preferred solution of the present invention, in step B1, the drill hole depth is not less than 1.0 m and the hole diameter is not less than the diameter of the connecting steel bars implanted in step B2. Through the above structure, the anchor connection between the upper composite lightweight pile and the lower composite lightweight pile is ensured.

As a preferred solution of the present invention, in step B4, during the process of placing the composite lightweight pile, the lower composite lightweight pile is tied with a hoisting rope, and the hoisting rope bound to the lower composite lightweight pile is not released. Through the above structure, the gravity of the lower composite lightweight pile is transmitted to the crane through the cable, so as to avoid the pulling effect of the lower composite lightweight pile on the upper prefabrication, thereby affecting the connection effect of the pile.

As a preferred solution of the present invention, in steps B1 and B3, the holes are quincunx-shaped holes.

In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

Lightweight soil material has light weight, low density and good compressive capacity. It can be constructed and poured in a small space. Compared with other types of lightweight materials, it has better durability, no pollution to the environment, and superior environmental protection characteristics. , And can significantly reduce the base stress and control post-construction settlement; the composite reinforced cage utilizes the tensile capacity of the geogrid, and the annular geogrid acts as a stirrup under the load of the pile top, so that the pile body can provide higher The composite reinforced cage can prevent the composite lightweight pile from cracking, and the composite lightweight soil can be combined with the composite reinforced cage to obtain the composite lightweight pile. structure. This structure reduces the in-situ effective stress of the foundation by replacing the rock and soil of the foundation. It can be used to balance the overburden load to reduce the additional stress of the overburden load in the foundation; secondly, the structure has high compressive strength and can effectively reinforce the foundation. , To significantly improve the bearing capacity of the foundation, the structure can also transmit the overlying load to the underlying rock and soil layer, avoid the increase of the additional stress of the existing buildings or structures, and realize the control of the deformation of the foundations of the existing buildings or structures. The purpose is to shorten the construction time and reduce the engineering risk at the same time.

Description of the drawings

Fig. 1 is a schematic diagram of the composite lightweight pile structure according to the present invention.

Fig. 2 is a schematic cross-sectional view of the steel protective pipe erected in the production of the composite lightweight pile according to the present invention.

Fig. 3 is a schematic plan view of erecting a steel protective pipe in the production of the composite lightweight pile according to the present invention.

Figure 4 is a schematic diagram of the connection between the composite stiffened cage and the pumping pipe outlet in the manufacture of the composite lightweight pile according to the present invention.

Fig. 5 is a schematic diagram of the arrangement of plum blossom-shaped holes in the composite lightweight pile of the present invention.

Fig. 6 is a schematic cross-sectional view of the composite lightweight pile-connected pile according to the present invention.

Icon: 1-composite reinforced cage; 11-vertical geogrid; 12-circular geogrid; 2-light soil; 10-protection pipe; 20-ring hoop; 30-bracket; 4-pumping pipe; 41- ring lock; 5- quincunx-shaped hole; 6-upper composite lightweight pile; 7-lower composite lightweight pile; 8-connecting steel bar; 9-ring plate.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not used to limit the present invention.

Example

1, the composite lightweight pile structure of the present invention, the composite lightweight pile includes a pile of lightweight soil 2 and a composite reinforced cage 1 embedded in it, and the composite reinforced cage 1 is a vertical geogrid arranged at intervals in the circumferential direction The grid 11 and the annular geogrid 12 arranged at vertical intervals are formed. The vertical geogrid 11 and the annular geogrid 12 intersect and connect as a whole. Two adjacent vertical geogrids 11 are connected to two adjacent annular geogrids. A quadrilateral mesh is formed between the grids 12.

In the above scenario:

The composite lightweight pile firstly fully exerts the compressive strength of the lightweight soil 2, while the composite reinforced cage 1 utilizes the tensile capacity of the geogrid. The annular geogrid 12 acts as a stirrup under the load of the pile top. This function enables the pile body to provide higher compressive resistance and avoid pile collapse or pile breakage. In addition, the composite reinforced cage 1 acts as a reinforcement to prevent the composite lightweight pile from cracking.

With reference to Figures 1, 2, 3, and 4, another technical problem to be solved by the present invention is to provide a method for manufacturing the above-mentioned composite lightweight pile structure. The method includes the following steps:

S1: Erection of steel protective pipes in sections from bottom to top;

S2: Sleeve the upper end of the composite stiffened cage 1 into the outer wall of the outlet end of the pumping pipe 4, and lock it with the ring lock 41, and send the composite stiffened cage 1 into the steel protective pipe;

S3: Slowly inject the light soil 2 into the steel protective pipe through the pumping pipe 4 until the light soil 2 is filled with the steel protective pipe, then loosen the ring lock 41 and extract the pumping pipe 4;

S4: When the light soil 2 reaches 80% of the design strength level, tie the fixed cable to the upper steel protective pipe and hang it to the crane, and remove the tripods in turn from top to bottom;

S5: Gradually level the composite lightweight pile to the ground through a crane and a fixed cable, and remove the steel protective pipe in sections.

In the above production method:

In step S1, the steel protective pipe is a half-open type, and each section of the steel protective pipe should be locked in time with a ring hoop 20, and a triangular bracket should be installed in the middle of the steel protective pipe.

In step S2, a weight is added to the lower part of the composite stiffened cage 1 to ensure the vertical verticality of the composite stiffened cage 1.

In step S4, the fixed cable is bound to the upper steel protective pipe and hung to the crane. Its function is to prevent the steel protective pipe and the composite lightweight pile from collapsing when the tripod is removed.

Another technical problem to be solved by the present invention is to provide a construction method of the above-mentioned composite lightweight pile structure. The method includes the following steps:

A1: Transport the composite lightweight piles that reach 100% of the design strength level to the site;

A2: The drilling rig drills holes at the designed pile position and cleans up the residue at the bottom of the hole to form a foundation hole;

A3: Hoist the composite light-weight piles into the foundation borehole by a crane, and connect the upper and lower sections of the composite light-weight piles by connecting piles;

A4: Pour cement mortar along the side of the composite lightweight pile to the top of the pile.

In the above construction method:

In step A2, the borehole diameter of the foundation is slightly larger than the diameter of the composite lightweight pile.

With reference to Figures 5 and 6, another technical problem to be solved by the present invention is to provide a method for connecting piles with the above-mentioned composite lightweight pile structure. The method includes the following steps:

B1: The corresponding quincunx holes 5 are arranged at the top of the lower composite light pile 7 and the bottom of the upper composite light pile 6 and drilled;

B2: After the lower composite lightweight pile 7 is put into the foundation to be drilled, the connecting steel bars 8 are implanted and grouted in the hole on the top of the pile;

B3: The plum-shaped hole 5 at the bottom of the upper composite lightweight pile 6 is aligned with the pile top connecting reinforcement 8 of the lower composite lightweight pile 7;

B4: The connection between the upper and lower composite light-weight piles is wrapped and fixed by ring-shaped steel plates, and the composite light-weight piles are slowly placed into the foundation borehole.

In the above-mentioned pile connection method:

In step B1, the drill hole depth is not less than 1.0m and the hole diameter is not less than the diameter of the connecting steel bar 8 implanted in step B2.

In step B4, during the process of placing the composite lightweight pile, the hoisting cable bound to the lower composite lightweight pile 7 is not released. Its function is that the gravity of the lower composite lightweight pile 7 is transmitted to the crane through the cable to avoid the lower composite lightweight pile. The pile 7 exerts a pulling effect on the upper composite lightweight pile, thereby affecting the connection effect of the connecting pile. The composite lightweight pile structure, production and construction method of the present invention can better solve the project construction requirements of complex interrelationships, and has the characteristics of novel structure, safety and reliability, investment saving, simple construction, etc., and the design process and construction method are clear.

The above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

The composite lightweight pile structure is characterized by comprising lightweight soil (2) and a composite reinforced cage (1), and the composite reinforced cage (1) is buried in the lightweight soil (2);

The composite reinforced cage (1) includes vertical geogrids (11) arranged at intervals along the circumferential direction and annular geogrids (12) arranged at intervals along the vertical direction, the vertical geogrids (11) and The annular geogrid (12) is converged and connected as a whole, and a quadrilateral mesh is formed between the two adjacent vertical geogrids (11) and the two adjacent annular geogrids (12).
The method for manufacturing a composite lightweight pile is characterized in that it is used to manufacture the composite lightweight pile structure according to claim 1 and comprises the following steps:

S1: Erection of protective pipes (10) from bottom to top;

S2: Send the composite stiffened cage (1) into the protective tube (10);

S3: Inject the light soil (2) into the protective pipe (10) until the light soil (2) fills the protective pipe (10);

S4: Remove the protective tube (10) in sections.
The method for manufacturing a composite lightweight pile according to claim 2, wherein the protective tube (10) is a half-open type, and the protective tube (10) is provided with a bracket (30) and a ring hoop (20). ), the annular hoop (20) is locked at the erection position of each section of the protective tube (10), and the bracket (30) is laid on the outside of each section of the protective tube (10).
The method for manufacturing a composite lightweight pile according to claim 2, characterized in that, in the step S2, a heavy hammer is provided at the lower part of the composite reinforced cage (1).
The method for manufacturing a composite lightweight pile according to claim 2, characterized in that, in the S2 step, the upper end of the composite reinforced cage (1) is sleeved into the outer wall of the outlet end of the pumping pipe (4) and used The ring lock (41) is locked.
The construction method of composite light-weight piles is characterized in that the construction of the composite light-weight pile structure according to claim 1 comprises the following steps:

A1: Form foundation drilling;

A2: Put the composite lightweight piles into the foundation borehole, and the upper and lower sections of the composite lightweight piles are connected by connecting piles;

A3: Pour cement mortar along the side of the composite lightweight pile to the top of the pile.
The pile connecting method of the composite lightweight pile structure is characterized in that it comprises the following steps:

B1: Arrange and drill holes at the top of the lower composite lightweight pile (7) and the bottom of the upper composite lightweight pile (6);

B2: After the lower composite lightweight pile (7) is drilled into the foundation, the connecting steel bar (8) is implanted and grouted into the hole on the top of the pile;

B3: The hole position at the bottom of the upper composite lightweight pile (6) is aligned with the pile top connecting reinforcement (8) implanted in the lower composite lightweight pile (7);

B4: The connection between the upper and lower composite lightweight piles is wrapped and fixed by a ring plate (9), and the composite lightweight piles are continuously placed into the foundation borehole.
The method for connecting piles with a composite lightweight pile structure according to claim 7, wherein in the step B1, the bore hole depth is not less than 1.0m and the hole diameter is not less than that of the connection implanted in the step B2 The diameter of the reinforcement (8).
The pile connection method of the composite lightweight pile structure according to claim 7, characterized in that: in the step B4, in the process of placing the composite lightweight pile, the lower composite lightweight pile (7) A hoisting rope is tied to the upper part, and the hoisting rope bound to the lower composite lightweight pile (7) is not released.
The pile connection method of the composite lightweight pile structure according to claim 7, characterized in that, in the steps B1 and B3, the hole position is a quincunx-shaped hole position (5).