Cement-soil mixing piles and their construction methods

Abstract

This invention relates to the field of cement-soil mixing pile technology, specifically a cement-soil mixing pile and its construction method. The pile body includes a mixing pile body comprising a pile column and flanges surrounding the pile column. Multiple flanges are evenly distributed around the pile column, and each flange is arc-shaped. The pile column has an inner circle line along its vertical cross-section, and the central axes of the flanges intersect at this inner circle line. A protective plate is provided at the outer circular node of each flange. The protective plate includes an abutting surface at the outer circular node of the flange and an embedded strip on the abutting surface, which is embedded at the outer circular node of the flange. This invention's mixing pile body, composed of a pile column and flanges evenly distributed around the pile column in an arc shape, results in more uniform mixing of the cement and soil, thereby improving the strength and stability of the foundation.

Description

Technical Field

[0001] This invention relates to the field of building mixing pile technology, and in particular to a cement-soil mixing pile and its construction method. Background Technology

[0002] Cement-soil mixing piles are a method for reinforcing saturated soft clay foundations. They use cement as a curing agent and, through specially designed mixing machinery, force the soft soil and curing agent to mix deep within the foundation. The series of physicochemical reactions between the curing agent and the soft soil cause the soft soil to harden into a high-quality foundation with integrity, water stability, and a certain strength.

[0003] In the prior art, Chinese patent application number CN201520820891.5 discloses a cement-soil mixing pile, in which a steel pipe for injecting cement grout is inserted into the middle of the pile body, and vertical prestress is applied to improve the overturning resistance of the cement-soil mixing pile body. This can reduce the thickness of the mixing pile retaining wall, reduce the number of mixing piles and the amount of construction work, and reduce the pollution to the surrounding environment. However, in actual use, the problem of insufficient uniformity in the mixing process is prone to occur, resulting in poor structural stability. Therefore, improvements are needed to the existing cement-soil mixing pile. Summary of the Invention

[0004] To solve the above problems, the present invention relates to a cement-soil mixing pile and its construction method, wherein the mixing pile body is composed of a pile column and flanges disposed on the outer periphery of the pile column. Multiple flanges are evenly distributed in an arc shape on the outer periphery of the pile column, which makes the mixing of cement and soil more uniform, thereby improving the strength and stability of the foundation.

[0005] The technical solution adopted in this invention is: a cement-soil mixing pile, comprising a mixing pile body, the mixing pile body comprising a pile column and flanges surrounding the outer periphery of the pile column, the flanges being provided in multiple ways, the multiple flanges being evenly distributed around the outer periphery of the pile column, the flanges being arc-shaped, the pile column having an inner circle line along its vertical cross section, the central axes of the flanges intersecting the inner circle line; a protective plate is provided at the outer circular node of the flange, the protective plate comprising an abutting surface abutting at the outer circular node of the flange and an embedded strip provided on the abutting surface, the embedded strip being embedded at the outer circular node of the flange.

[0006] A further improvement to the above scheme is that the pile column has at least one reinforcing part in the vertical direction, and the outer diameter of the reinforcing part is larger than the diameter of the pile column.

[0007] A further improvement to the above scheme is that the cross-sectional shape of the pile is circular, and the pile includes a low column part, a support part and an extension part arranged sequentially from bottom to top. The density of the low column part is greater than or equal to the density of the support part, and the density of the support part is greater than or equal to the density of the extension part.

[0008] A further improvement to the above scheme is that a forming baffle is provided at the point where the outer diameter of the pile is tangent to the flange, and the forming baffle has a transition arc surface, which is used to form a transition surface at the point where the flange is tangent to the outer diameter of the pile.

[0009] A further improvement to the above scheme is that the forming baffle is a metal baffle or a baffle made of SMC composite material.

[0010] A further improvement to the above scheme is that the number of flanges is three or more, and the central axis of each flange intersects the inner circle line.

[0011] A further improvement to the above solution is that the protective plate is a metal protective plate or a protective plate made of SMC composite material.

[0012] A construction method for cement-soil mixing piles, comprising the aforementioned cement-soil mixing piles;

[0013] The construction method includes the following steps: Step S1, positioning and sinking: perform ground positioning for the location where cement mixing piles need to be driven in; Step S2, drilling elevation: After positioning the ground, drilling is carried out using a cement-soil mixing pile machine to form pile holes. The pile holes include a main hole for forming the pile column and a groove for forming the flange. Step S3: Insert the guard plate vertically at the outer circle node of the flange; Step S4, one-time grouting and lifting: the cement-soil mixing pile machine mixes and fills the pile hole and lifts it. The grouting fills the pile hole to form a rough mixing pile body. The cement-soil mixing pile machine rises to the designated height and forms a certain distance from the ground surface. Step S5, First re-mixing: After completing one shotcrete lifting, the rough mixing pile body formed is re-mixed from top to bottom by the cement-soil mixing pile machine to form a first re-mixed pile body; Step S6, Secondary mixing: After the first mixing is completed, the grouting head of the cement-soil mixing pile machine is at the bottom of the first mixed pile body. At this time, the grouting head of the cement-soil mixing pile machine rises and is lifted from bottom to top during the rising process to perform secondary mixing to form a secondary mixed pile body. Step S7, three-stage re-mixing: After the second re-mixing is completed, the grouting head of the cement-soil mixing pile machine is lowered to a certain depth to perform a third re-mixing on the upper part of the pile body after the second re-mixing. After the descent is completed, it is raised again. During the raising process, re-mixing is performed to form a pile body with three-stage re-mixing. Step S8: After the pile body is solidified by three rounds of re-mixing, a mixing pile body is formed.

[0014] A further improvement to the above scheme is that, in step S2, the drilling elevation is determined by drilling with a cement-soil mixing pile machine. During the drilling process, the main hole is drilled first, and then grooves are drilled sequentially on the outside of the main hole.

[0015] A further improvement to the above scheme is that, in step S3, the protective plate is inserted vertically by vibration, with one end submerged to the bottom of the groove.

[0016] A further improvement to the above scheme is that, in step S4, the slurry is sprayed to lift and fill the main hole and groove with slurry; in steps 5 to 7, slurry is sprayed during the first, second and third re-stirring processes.

[0017] The beneficial effects of this invention are: Compared to existing cement-mixing piles, this invention features flanges on the outer periphery of the pile column. Firstly, the mixing pile consists of a pile column and flanges evenly distributed in an arc shape around its periphery. This ensures more uniform mixing of the cement and soil, thereby improving the strength and stability of the foundation. Secondly, the bearing capacity of the mixing pile is significantly higher than other foundation treatment methods, meeting the needs of foundation treatment under various working conditions. This is due to the flange design, which gives the pile a greater advantage in bearing capacity. Furthermore, because the flanges are evenly distributed in an arc shape, the settlement of the mixing pile is very small and negligible, requiring no post-treatment. This greatly reduces construction time and cost, improving project efficiency. Thirdly, the mixing pile exhibits good soil stability and can be used in various environments, including fill, collapsible loess, and expansive soil. This allows the technology to perform well under various geological conditions. Finally, the mixing pile allows for rapid construction, significantly shortening the construction period and improving project progress. Simultaneously, this technology has a wide range of applications and can be used for various types of foundation treatment, such as buildings, roads, and bridges. This has brought significant economic and social benefits to enterprises. Cement-soil mixing piles offer technical advantages such as increased foundation bearing capacity, reduced later-stage settlement, improved soil stability, rapid construction, and wide applicability. These advantages make this technology promising for applications in fields such as construction and transportation.

[0018] This cement-soil mixing pile construction method, through steps such as positioning and sinking, drilling elevation, inserting protective plates, initial grouting and lifting, initial re-mixing, secondary re-mixing, and tertiary re-mixing, effectively forms the mixing pile body. Specific technical benefits include: improved construction quality: multiple re-mixing ensures the uniformity and density of the cement-soil mixing pile, thus improving construction quality. Reduced construction time: the initial grouting and lifting, secondary and tertiary re-mixing steps allow for rapid completion of the cement-soil mixing pile construction, shortening construction time. Increased work efficiency: this method reduces malfunctions and problems during construction, improving work efficiency. Reduced costs: multiple re-mixing reduces cement-soil waste, lowering costs. Applicable to various geological conditions: this method is suitable for various geological conditions, such as soft soil foundations and sandy soil foundations, exhibiting wide applicability. In conclusion, this cement-soil mixing pile construction method improves construction quality, shortens construction time, reduces costs, and is applicable to various geological conditions, demonstrating excellent technical effects.

[0019] The improvements to the secondary and tertiary re-mixing processes were achieved by optimizing the structural design of the grouting head and adjusting the lifting and re-mixing method. Specifically, the grouting head adopted a new type of conical structure, which better conforms to the pile surface, thereby improving the lifting and penetration efficiency. During the secondary and tertiary re-mixing processes, the grouting head used a bottom-up and inside-out lifting and re-mixing method during both its ascent and descent. This method better mixes the cement slurry with the soil, thereby improving the strength and stability of the pile. Through these improvements, the construction efficiency of secondary and tertiary re-mixing was significantly improved, while the quality and stability of the pile were effectively guaranteed. Attached Figure Description

[0020] Figure 1 This is a three-dimensional schematic diagram of the cement-soil mixing pile of the present invention; Figure 2 for Figure 1 Side view of a cement-soil mixing pile; Figure 3 for Figure 1 A side view of another embodiment of a cement-soil mixing pile; Figure 4 for Figure 1 Front view of a cement-soil mixing pile; Figure 5 This is a schematic diagram of the construction method of the cement-soil mixing pile of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 10 for mixing pile body, 1 for pile column, 11 for reinforcement part, 12 for forming baffle, 2 for flange, 21 for protective plate, 211 for contact surface, and 212 for embedded strip. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0023] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] like Figures 1-5As shown, in one embodiment of the present invention, a cement-soil mixing pile is provided, including a mixing pile body 10. The mixing pile body 10 includes a pile column 1 and flanges 2 surrounding the outer periphery of the pile column 1. Multiple flanges 2 are provided, evenly distributed around the outer periphery of the pile column 1. The flanges 2 are arc-shaped. The pile column 1 has an inner circle line along its vertical cross-section, and the central axes of the flanges 2 intersect at the inner circle line. A protective plate 21 is provided at the outer circular node of the flange 2. The protective plate 21 includes an abutment surface 211 abutting against the outer circular node of the flange 2 and an embedded strip 212 disposed on the abutment surface 211. The embedded strip 212 is embedded at the outer circular node of the flange 2. In this embodiment, flanges 2 are provided around the outer periphery of the pile column 1. First, the mixing pile body 10 is composed of a pile column 1 and flanges 2 disposed around the outer periphery of the pile column 1. Multiple flanges 2 are evenly distributed around the outer periphery of the pile column 1 in an arc shape, which makes the mixing of cement and soil more uniform, thereby improving the strength and stability of the foundation. Secondly, the bearing capacity of the mixing pile 10 is significantly higher than other foundation treatment methods, meeting the foundation treatment requirements under various working conditions. This is due to the design of the flange 2, which gives the pile 1 a greater advantage in bearing capacity. Furthermore, because the flange 2 is evenly distributed in an arc shape, the settlement of the mixing pile 10 is very small and negligible, requiring no post-treatment. This greatly reduces construction time and cost, improving project efficiency. Moreover, the mixing pile 10 exhibits good soil stability and can be used in various environments, including fill, collapsible loess, and expansive soil. This allows the technology to perform well under various geological conditions. Finally, the mixing pile 10 has a fast construction speed, significantly shortening the construction period and improving project progress. Simultaneously, this technology has a wide range of applications, applicable to various types of foundation treatment, such as buildings, roads, and bridges. Cement-soil mixing piles offer advantages such as increased foundation bearing capacity, reduced post-settlement, improved soil stability, fast construction speed, and wide application. This technology has broad application prospects in the fields of construction and transportation. A protective plate 21 is provided at the outer circular node of flange 2 to prevent cement and soil from leaking out during the mixing process and improve the construction quality.

[0026] In the above embodiments, the pile 1 has at least one reinforcing part 11 in the vertical direction, and the outer diameter of the reinforcing part 11 is larger than the diameter of the pile 1. By providing the reinforcing part 11, the structural strength of the mixing pile 10 can be further improved, and the pile 1 can be protected from damage by external forces. Better support effect and extension performance are achieved through the density difference of different cross-sectional sections. Specifically, the lower column section has a higher density, providing better support force, allowing the entire pile 1 to remain stable under large loads. The density of the supporting part is between that of the lower column section and the extension part, providing a certain buffer and transition, allowing the pile 1 to better adapt to environmental changes under stress. The extension part has a lower density, providing better extension and flexibility, allowing the pile 1 to better adapt to changes in soil and geological conditions under smaller loads. Therefore, the pile 1 can exhibit better performance and stability under various environmental conditions, improving the service life and reliability of the pile 1.

[0027] In another embodiment, a forming baffle 12 is provided at the tangent point between the outer diameter of the pile 1 and the flange 2. The forming baffle 12 has a transition arc surface, which forms a transition surface at the tangent point between the flange 2 and the outer diameter of the pile 1. The forming baffle 12 is made of metal or SMC composite material. Improved construction quality: The transition arc surface ensures a tight fit between the forming baffle 12 and the outer diameter of the pile 1, avoiding problems such as grout leakage and uneven forming, thereby improving construction quality. Enhanced structural stability: The transition arc surface between the forming baffle 12 and the outer diameter of the pile 1 forms a more stable connection, enhancing the overall structural stability of the pile 1. Reduced construction difficulty: The design of the transition arc surface makes the installation of the forming baffle 12 more convenient, reducing the operational difficulty during construction. Improved material utilization: The forming baffle 12, made of metal or SMC composite material, has good plasticity and durability, and can better adapt to the shape and size of the pile 1, thereby reducing material waste and improving material utilization.

[0028] In another embodiment, there are three or more flanges 2, and the central axis of each flange 2 intersects the inner circle line. The presence of flanges 2 increases the strength and stability of the pile 1, enabling it to better resist external forces and ensure structural safety. The large number of flanges 2 allows the pile 1 to adapt to more usage environments, including various geological conditions and external loads. Because the central axes of the flanges 2 intersect the inner circle line, the pile 1 can be more easily positioned and fixed during installation. The design of the flanges 2 can disperse seismic forces, enhancing the seismic performance of the pile 1.

[0029] In another embodiment, the guard plate 21 is a metal guard plate 21 or a guard plate 21 made of SMC composite material. The metal baffle or the molded baffle 12 made of SMC composite material has good plasticity and durability.

[0030] like Figures 1-5 As shown, a construction method for cement-soil mixing piles includes the aforementioned cement-soil mixing piles; the construction method includes the following steps: Step S1, positioning and sinking: perform ground positioning for the location where cement mixing piles need to be driven in; Step S2, drilling elevation: After positioning the ground, drilling is carried out using a cement-soil mixing pile machine to form pile holes. The pile holes include a main hole for forming the pile column 1 and a groove for forming the flange 2. Step S3, insert the guard plate 21, and insert the guard plate 21 vertically at the outer diameter node of the groove of the flange 2; Step S4, one-time grouting and lifting: the pile hole is mixed and filled by the cement-soil mixing pile machine and the grout is sprayed to fill the pile hole to form a rough mixing pile body 10. The cement-soil mixing pile machine rises to the specified height and forms a certain distance from the ground surface. Step S5, First re-mixing: After completing one shotcrete lifting, the rough mixing pile body 10 formed by the cement-soil mixing pile machine is re-mixed from top to bottom for the first time to form a re-mixed pile body. Step S6, Secondary mixing: After the first mixing is completed, the grouting head of the cement-soil mixing pile machine is at the bottom of the first mixed pile body. At this time, the grouting head of the cement-soil mixing pile machine rises and is lifted from bottom to top during the rising process to perform secondary mixing to form a secondary mixed pile body. Step S7, three-stage re-mixing: After the second re-mixing is completed, the grouting head of the cement-soil mixing pile machine is lowered to a certain depth to perform a third re-mixing on the upper part of the pile body after the second re-mixing. After the descent is completed, it is raised again. During the raising process, re-mixing is performed to form a pile body with three-stage re-mixing. Step S8: After the pile body is solidified by three rounds of re-mixing, a mixing pile body 10 is formed.

[0031] In step S2, the drilling elevation is determined by drilling with a cement-soil mixing pile machine. During the drilling process, the main hole is drilled first, and then grooves are drilled on the outside of the main hole in sequence.

[0032] In step S3, the guard plate 21 is inserted by vibration, and one end of the guard plate 21 is inserted vertically into the groove.

[0033] In step S4, a single spraying lift is performed, filling the main hole and groove with slurry; In steps S5-S7, grout is sprayed during the first, second, and third re-mixing processes. The sprayed grout mixes thoroughly with the pile material, increasing the cement-soil content and improving pile strength. Multiple re-mixing ensures more uniform mixing of the pile material, reducing voids and segregation, and enhancing the pile's bearing capacity and stability. This more uniform mixing allows the pile to better transfer loads during stress, reducing the likelihood of pile fracture and failure, and improving pile integrity.

[0034] The construction method for this cement-soil mixing pile involves several steps, including positioning and sinking, drilling elevation, insertion of the protective plate 21, initial grouting and lifting, initial re-mixing, secondary re-mixing, and tertiary re-mixing, effectively forming the mixing pile body 10. Specific technical benefits include: improved construction quality: multiple re-mixing ensures the uniformity and density of the cement-soil mixing pile, thus improving construction quality. Reduced construction time: the initial grouting and lifting, secondary and tertiary re-mixing steps allow for rapid completion of the cement-soil mixing pile construction, shortening construction time. Increased work efficiency: this method reduces malfunctions and problems during construction, improving work efficiency. Reduced costs: multiple re-mixing reduces cement-soil waste, lowering costs. Applicable to various geological conditions: this method is suitable for various geological conditions, such as soft soil foundations and sandy soil foundations, exhibiting wide applicability. In conclusion, this cement-soil mixing pile construction method improves construction quality, shortens construction time, reduces costs, and is applicable to various geological conditions.

[0035] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A cement-soil mixing pile, characterized in that: The system includes a mixing pile body, which comprises a pile column and flanges surrounding the pile column. Multiple flanges are evenly distributed around the pile column, and each flange is arc-shaped. The pile column has an inner circle line along its vertical cross-section, and the central axes of the flanges intersect at this inner circle line. A protective plate is provided at the outer circular node of the flange. The protective plate includes an abutting surface that abuts against the outer circular node of the flange and an embedded strip disposed on the abutting surface. The embedded strip is embedded at the outer circular node of the flange.

2. The cement-soil mixing pile according to claim 1, characterized in that: The pile has at least one reinforcing part in the vertical direction, and the outer diameter of the reinforcing part is larger than the diameter of the pile.

3. The cement-soil mixing pile according to claim 1, characterized in that: The pile has a circular cross-sectional shape and includes a low column portion, a support portion, and an extension portion arranged sequentially from bottom to top. The density of the low column portion is greater than or equal to the density of the support portion, and the density of the support portion is greater than or equal to the density of the extension portion.

4. The cement-soil mixing pile according to claim 1, characterized in that: A forming baffle is provided at the point where the outer diameter of the pile is tangent to the flange. The forming baffle is provided with a transition arc surface, which is used to form a transition surface at the point where the flange is tangent to the outer diameter of the pile. The forming baffle is a metal baffle or a baffle made of SMC composite material.

5. The cement-soil mixing pile according to claim 1, characterized in that: The number of flanges is three or more, and the central axis of each flange intersects the inner circle line.

6. The cement-soil mixing pile according to claim 1, characterized in that: The protective plate is a metal protective plate or a protective plate made of SMC composite material.

7. A construction method for cement-soil mixing piles, characterized in that: Including the cement-soil mixing pile as described in any one of claims 1 to 6; The construction method includes the following steps: Step S1, positioning and sinking: perform ground positioning for the location where cement mixing piles need to be driven in; Step S2, drilling elevation: After positioning the ground, drilling is carried out using a cement-soil mixing pile machine to form pile holes. The pile holes include a main hole for forming the pile column and a groove for forming the flange. Step S3: Insert the guard plate vertically at the outer circle node of the flange; Step S4, one-time grouting and lifting: the cement-soil mixing pile machine mixes and fills the pile hole and lifts it. The grouting fills the pile hole to form a rough mixing pile body. The cement-soil mixing pile machine rises to the designated height and forms a certain distance from the ground surface. Step S5, First re-mixing: After completing one shotcrete lifting, the rough mixing pile body formed is re-mixed from top to bottom by the cement-soil mixing pile machine to form a first re-mixed pile body; Step S6, Secondary mixing: After the first mixing is completed, the grouting head of the cement-soil mixing pile machine is at the bottom of the first mixed pile body. At this time, the grouting head of the cement-soil mixing pile machine rises and is lifted from bottom to top during the rising process to perform secondary mixing to form a secondary mixed pile body. Step S7, three-stage re-mixing: After the second re-mixing is completed, the grouting head of the cement-soil mixing pile machine is lowered to a certain depth to perform a third re-mixing on the upper part of the pile body after the second re-mixing. After the descent is completed, it is raised again. During the raising process, re-mixing is performed to form a pile body with three-stage re-mixing. Step S8: After the pile body is solidified by three rounds of re-mixing, a mixing pile body is formed.

8. The construction method for cement-soil mixing piles according to claim 7, characterized in that: In step S2, the drilling elevation is determined by drilling with a cement-soil mixing pile machine. During the drilling process, the main hole is drilled first, and then grooves are drilled on the outside of the main hole in sequence.

9. The construction method for cement-soil mixing piles according to claim 7, characterized in that: In step S3, the protective plate is inserted by vibration, with one end submerged in the bottom of the groove.

10. The construction method for cement-soil mixing piles according to claim 7, characterized in that: In step S4, a single spraying lift is performed, filling the main hole and groove with slurry; During the first, second, and third re-mixing processes, slurry was sprayed out during the re-mixing.

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