Prefabricated bearing platform and pile foundation connecting structure, construction method and simulation experiment method

Abstract

The invention relates to a prefabricated bearing platform and pile foundation connecting structure, a construction method and a simulation experiment method.The structure comprises a prefabricated bearing platform, a pile foundation and a connecting piece, a plurality of connecting holes are formed in the bottom of the prefabricated bearing platform, a plurality of bolt holes are formed in the connecting piece, and the connecting holes and the bolt holes are matched with each other and fixedly connected through high-strength bolts; a groove is formed in the top of the prefabricated pile foundation, a protrusion is arranged at the bottom of the connecting piece, the protrusion is embedded into the groove during connection, and the space between the protrusion and the groove is filled with a high-performance grouting material. According to the construction method, rapid construction is achieved through factory production and on-site efficient assembly of prefabricated parts, the high-strength connecting pieces and the secondary grouting technology are adopted, the simulation method simulates the actual load condition through finite element analysis, the mechanical property of the structure is evaluated, and the actual experiment cost is reduced. Compared with the prior art, the connecting structure has the advantages of high connecting strength, simplified construction and the like.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a prefabricated cap and pile foundation connection structure, a construction method and a simulation experiment method. Background Art

[0002] The traditional connection method between the cap and the pile foundation mostly adopts cast-in-place concrete technology or simple mechanical connection. However, in actual construction, the cast-in-place technology is not only time-consuming and costly, but also difficult to ensure construction quality in complex environments. At the same time, the traditional mechanical connection method is prone to problems such as loose connection and insufficient fatigue resistance under high load and high vibration conditions, resulting in reduced stability of the overall structure. Therefore, there is an urgent need for a high-performance connection structure that can quickly, efficiently and stably connect the prefabricated cap and the pile foundation to meet the needs of modern engineering for high bearing capacity, rapid construction and high safety.

[0003] Utility model CN210482021U proposes a prefabricated assembled pier column structure connected by inserting steel bars into corrugated pipes, a groove is provided on the upper surface of the cap, a support column for supporting the bottom surface of the pier column is provided inside the groove, a number of corrugated pipes are vertically buried around the support column inside the groove, a number of main bars at the bottom of the pier column correspond to the corrugated pipes one by one and are inserted into the corrugated pipes, an inner filling layer is provided inside the corrugated pipes, and a concrete filling layer is poured inside the grooves. During installation, the cap and the pier column are connected by the grooves and supports, which is difficult to align and has limited connection strength. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art such as high construction cost and low connection strength and to provide a prefabricated cap and pile foundation connection structure, construction method and simulation experimental method.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] According to one aspect of the present invention, there is provided a prefabricated cap and pile foundation connection structure, comprising a prefabricated cap, a pile foundation and a connection piece, wherein a plurality of connection holes are provided at the bottom of the prefabricated cap, a plurality of bolt holes are provided at the connection piece, and the connection holes and the bolt holes cooperate with each other and are fixedly connected by high-strength bolts;

[0007] A groove is provided on the top of the prefabricated pile foundation, and a protrusion is provided on the bottom of the connecting piece. The protrusion is embedded in the groove during connection, and high-performance grouting material is filled between the protrusion and the groove.

[0008] Furthermore, the connecting piece is a flange structure with a cross-shaped outer edge, and the number of bolt holes is eight, which are distributed on the four ends of the cross in groups of two.

[0009] Furthermore, the upper and lower end surfaces of the connecting piece are both planes, and the inner wall of the groove is a rough surface or is provided with reinforcing ribs.

[0010] Furthermore, an elastic washer is provided in the bolt hole.

[0011] Furthermore, the material of the connecting piece is steel fiber reinforced concrete or ultra-high performance concrete, and the material of the high-performance grouting material is high-performance grouting material or polymer cement-based material.

[0012] According to another aspect of the present invention, a construction method of a prefabricated cap and pile foundation connection structure is provided, comprising the following steps:

[0013] Use high-precision molds to prefabricate the caps and pile foundations. During the mold making process, the connection holes and grooves are formed at one time to ensure the precise fit of the connection components.

[0014] The prefabricated cap and pile foundation are transported to the construction site by means of transportation equipment, and the prefabricated cap is aligned with the pile foundation using hoisting equipment so that the bolt holes and the connection holes are aligned;

[0015] Pass the high-strength bolts through the bolt holes and connection holes in sequence, ensuring that each high-strength bolt reaches the standard torque. After tightening, inject high-performance grouting material into the groove, use a vibrating tool to ensure that the grouting is dense and has no gaps, and place the connection structure until the high-performance grouting material solidifies;

[0016] Check the overall verticality of the prefabricated foundation, use laser measuring tools to ensure that the error is within the allowable range, test the torque value of high-strength bolts and the density of grouting, and complete the quality acceptance.

[0017] Furthermore, before the hoisting equipment aligns the prefabricated cap with the pile foundation, the pile foundation position and the verticality and horizontality of the prefabricated cap need to be calibrated by laser measuring instruments or other positioning tools to ensure accurate alignment of the components during assembly.

[0018] Furthermore, a method for ensuring that each high-strength bolt reaches the standard torque is to use a torque wrench to tighten the high-strength bolts one by one according to the size requirements of the standard torque.

[0019] Furthermore, after the pile foundation is prefabricated, the surface of the pile foundation is subjected to anti-corrosion treatment.

[0020] The present invention also provides a simulation experiment method for a prefabricated cap and pile foundation connection structure, which is characterized by comprising the following steps:

[0021] Use ABAQUS to establish a 3D model of the system consisting of precast caps and pile foundations. The 3D model includes the precast caps, precast pile foundations, connectors, high-strength bolts, and the model of the secondary grouting area for filling with high-performance grouting materials. The material of the model uses nonlinear material properties.

[0022] Set the geometric parameters of precast caps, pile foundations and connectors, and set the material properties of precast caps, pile foundations, connectors, high-strength bolts and high-performance grouting materials;

[0023] Apply boundary conditions and loads to the three-dimensional model. The boundary conditions include the fixation of the pile base and the friction force on the pile side. The loads include vertical loads, horizontal loads and dynamic conditions.

[0024] Perform static analysis, dynamic response analysis, fatigue life analysis, and result analysis and verification on 3D models with applied boundary conditions and loads.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The present invention connects the prefabricated cap and the connecting parts through high-strength bolts, connects the pile foundation and the connecting parts through the cooperation of the groove and the connecting parts and filling with high-performance grouting materials, adopts high-strength bolts, flange connection and secondary grouting technology, and significantly improves the compression, shear and bending resistance between the cap and the pile foundation; in addition, the prefabricated cap and the pile foundation are prefabricated parts, and the prefabricated production and on-site rapid assembly greatly shorten the construction period and reduce the risk of construction delays. During the on-site installation process, standardized connecting parts and high-precision prefabricated components reduce complex construction steps and improve assembly efficiency.

[0027] 2. The connector of the present invention uses ultra-high performance concrete (UHPC) or steel fiber reinforced concrete (SFRC) to further enhance the overall bearing capacity and seismic performance of the structure.

[0028] 3. The construction method of the present invention realizes rapid construction through factory production of prefabricated components and efficient on-site assembly, and is suitable for foundation construction of large-scale projects such as bridges and docks. The high-strength connectors and secondary grouting technology are used to enable the structure to exhibit excellent seismic resistance in a high-vibration environment, and is suitable for large-scale foundation projects in earthquake-prone areas. The uniform force design of flanges and bolts effectively alleviates the local stress concentration caused by vibration, ensuring the long-term stability of the structure.

[0029] 4. The simulation method of the present invention simulates actual load conditions through finite element analysis (FEA), evaluates the mechanical properties of the structure, and reduces the actual experimental cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the connection structure of the assembled pile cap;

[0031] Figure 2 The distribution diagram of the bolt holes of the cap;

[0032] Figure 3 This is the top view of the flange of the connecting part;

[0033] In the figure, 1. prefabricated foundation, 2. pile foundation, 3. connecting parts, 4. bolt holes, 5. connecting holes, 6. high-strength bolts, 7. grooves, 8. high-performance grouting materials. DETAILED DESCRIPTION

[0034] 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 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 should fall within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment shows a prefabricated cap and pile foundation connection structure, which realizes a stable connection between the prefabricated cap 1 and the pile foundation 2 through a high-performance connector 3, and is suitable for foundation engineering of bridges, docks and high-rise buildings.

[0037] like Figure 1-Figure 3 As shown, a plurality of connection holes 5 matching the connection member 3 are arranged at the bottom of the prefabricated pedestal 1. The connection member 3 adopts a flange structure, and the upper and lower surfaces of the flange are designed to be flat, so as to fit closely with the pedestal and the pile foundation. A plurality of bolt holes 4 are evenly distributed around the flange, and the prefabricated pedestal 1 and the pile foundation 2 are fastened together by high-strength bolts 6. As a preferred embodiment, the number of bolt holes 4, connection holes 5 and high-strength bolts 6 are eight, and they are radially distributed in four directions of the connection area in a group of two. The distance between each group of bolt holes 4 is uniform, so as to avoid local stress concentration and ensure uniform force on the overall structure. In particular, an elastic gasket is arranged in the bolt hole 4 to further enhance the vibration resistance and fatigue resistance.

[0038] A groove 7 is provided at the top of the pile foundation 2, and a protrusion is provided at the bottom of the connector 3. The protrusion is embedded in the groove 7 during connection. The depth of the groove 7 is determined according to the height of the embedded part of the connector 3 to ensure that the connector 3 can be fully embedded during the installation process, thereby improving the stability of the connection. In order to enhance the shear resistance, the inner wall of the groove 7 can be designed as a rough surface or reinforced ribs can be provided. After the connector 3 is embedded in the groove 7, a high-performance grouting material 8 is injected through the grouting port. After solidification, the high-performance grouting material 8 is tightly combined with the pile foundation 2 and the connector 3 to form an overall high-bearing capacity tight connection, which enhances the shear resistance, compression resistance and anti-seepage performance.

[0039] As a preferred embodiment, the connector 3 is made of high-strength materials with excellent shear, tensile and bending resistance, so as to achieve high bearing capacity and long-term stability, such as steel fiber reinforced concrete (SFRC) or ultra-high performance concrete (UHPC), which has high compressive strength, high crack resistance and low permeability, and can effectively cope with high loads, frequent vibrations and harsh environmental conditions. By using this material, the seismic resistance, fatigue resistance and long-term service life of the connection structure can be greatly improved. In addition, the material of the high-performance grouting material 8 is a high-performance grouting material or a polymer cement-based material.

[0040] The structure effectively improves the compression, shear and seismic performance through double fixing method (high-strength bolt connection and grouting material reinforcement), and is suitable for high load and complex geological environment.

[0041] Example 2

[0042] This embodiment introduces a construction method for the prefabricated cap and pile foundation connection structure based on the embodiment 1, which realizes rapid construction through factory production of prefabricated components and efficient on-site assembly, and is suitable for foundation construction of large-scale projects such as bridges and docks. The method includes the following steps:

[0043] S1, prefabricated component manufacturing stage: The cap 1 and pile foundation 2 are prefabricated in the factory, and each component needs to be preset with connection holes and grooves to ensure the precise matching of the connection components. Therefore, high-precision molds are used to ensure the dimensional accuracy of the prefabricated components and the consistency of the connection hole positions. The connection hole 5 at the bottom of the prefabricated cap and the groove 7 at the top of the prefabricated pile foundation are formed at one time during the mold making process to reduce errors. The connector 3 is embedded in the prefabricated groove 7, and there is a gap between the protrusion at the bottom of the connector 3 and the groove 7 for filling with high-performance grouting material 8 during construction. In particular, the surface of the pile foundation 2 is treated with anti-corrosion to enhance its durability.

[0044] S2, transportation and on-site hoisting stage: The prefabricated prefabricated cap 1 and pile foundation 2 are transported to the construction site by transportation equipment. Before hoisting, the pile foundation position and the cap level need to be calibrated to ensure accurate alignment of components during assembly. Use hoisting equipment to slowly align the cap with the pile foundation so that the flange and the connection hole are aligned.

[0045] S3, connection tightening and grouting reinforcement stage: including bolt connection and secondary grouting curing. First, the high-strength bolts 6 are passed through the bolt holes 4 and the connection holes 5 in sequence, and tightened one by one according to the design requirements using a torque wrench to ensure that each high-strength bolt 6 reaches the standard torque. After tightening, the verticality and horizontality of the prefabricated cap 1 and the pile foundation 2 can be adjusted by laser measuring instruments or other positioning tools to ensure the accuracy of assembly.

[0046] High-performance grouting material 8 is injected into the groove 7 through the grouting port to fill the gap between the connector 3 and the pile foundation 2, and then a vibrating tool is used to ensure that the grouting is dense and void-free. When the high-performance grouting material 8 solidifies, an overall reinforced cap-pile foundation connection system is formed.

[0047] S4, Quality Acceptance Stage: Check the quality of the overall connection structure, check the overall verticality of the pedestal, use laser measurement tools to ensure that the error is within the allowable range, and test the torque value of the bolts and the density of the grouting to complete the quality acceptance

[0048] Example 3

[0049] In order to verify the bearing capacity, seismic performance and long-term stability of the high-performance connection structure of the cap-pile foundation connection system formed by Examples 1 and 2 under different working conditions, the actual load conditions are simulated by finite element analysis (FEA), the mechanical properties of the structure are evaluated, and the actual experimental cost is reduced. The simulation experimental method steps are as follows:

[0050] S1. Establishment of numerical simulation model:

[0051] S1.1. Modeling tools and software:

[0052] A three-dimensional model of the precast cap-high pile connection system was established using ABAQUS. The model includes the precast cap 1, pile foundation 2, connector 3, flange, high-strength bolt 6 and secondary grouting area. The material model uses nonlinear material properties.

[0053] S2. Model parameter setting:

[0054] S2.1. Geometric parameters:

[0055] Set the model geometric parameters required for the simulation experiment, including the geometric parameters of the prefabricated cap 1, pile foundation 2 and connector 3. The details are as follows:

[0056] Prefabricated foundation dimensions: 4m long, 4m wide, 1m high;

[0057] The pile diameter is 1m and the pile length is 30m;

[0058] The thickness of the connecting flange is 0.2m and the diameter is 1.5m.

[0059] S2.2. Material properties:

[0060] The model material properties required for the simulation experiment are set, including the material properties of the prefabricated cap (1), pile foundation (2), connector (3), high-strength bolt (6) and high-performance grouting material (8). The details are as follows:

[0061] Precast cap and pile foundation materials: C60 concrete;

[0062] Connector and flange material: Ultra-high performance concrete (UHPC); material elastic modulus 45GPa, material tensile strength 8MPa;

[0063] High-strength bolts: yield strength 900MPa, ultimate strength 1100MPa;

[0064] Secondary grouting material: polymer grouting material, elastic modulus 25GPa.

[0065] S2.3. Boundary conditions and loads:

[0066] Apply boundary conditions and loads to the 3D model as follows:

[0067] Fixed boundary conditions: the bottom of the pile foundation is fixed, and the friction force is considered on the side of the pile;

[0068] Vertical load: Apply a vertical concentrated load of 5000kN;

[0069] Horizontal load: simulate wind load and earthquake action, apply 300kN horizontal force;

[0070] Dynamic conditions: The El Centro seismic wave is used for time domain analysis to simulate the dynamic response under a magnitude 8 earthquake.

[0071] S3. Numerical simulation analysis steps:

[0072] S3.1. Static analysis: evaluate the bearing capacity and stress distribution of the structure under vertical and horizontal loads;

[0073] S3.2, Dynamic response analysis: simulate the structural response under seismic loads and evaluate the seismic performance;

[0074] S3.3, Fatigue life analysis: simulate the fatigue life under long-term load and vibration conditions and predict the long-term stability of the structure;

[0075] S4. Result analysis and verification: Through the above numerical simulation, the high stability and high bearing capacity of the prefabricated cap-high pile system high-performance connection structure of the present invention under extreme load and earthquake conditions are verified.

[0076] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A prefabricated cap and pile foundation connection structure, characterized in that: It comprises a prefabricated cap (1), a pile foundation (2) and a connecting piece (3), wherein the bottom of the prefabricated cap (1) is provided with a plurality of connecting holes (5), the connecting piece (3) is provided with a plurality of bolt holes (4), and the connecting holes (5) and the bolt holes (4) cooperate with each other and are fixedly connected by high-strength bolts (6); The top of the prefabricated pile foundation (2) is provided with a groove (7), the bottom of the connecting piece (3) is provided with a protrusion, the protrusion is embedded in the groove (7) during connection, and the space between the protrusion and the groove (7) is filled with high-performance grouting material (8).

2. A prefabricated cap and pile foundation connection structure according to claim 1, characterized in that: The connecting piece (3) is a flange structure with a cross-shaped outer edge. The number of the bolt holes (4) is eight and they are arranged in groups of two and are distributed on the four ends of the cross.

3. The prefabricated cap and pile foundation connection structure according to claim 1, characterized in that: The upper and lower end surfaces of the connecting member (3) are both planes, and the inner wall of the groove is a rough surface or is provided with reinforcing ribs.

4. The prefabricated cap and pile foundation connection structure according to claim 1, characterized in that: An elastic washer is arranged in the bolt hole (4).

5. The prefabricated cap and pile foundation connection structure according to claim 1, characterized in that: The material of the connecting piece (3) is steel fiber reinforced concrete or ultra-high performance concrete, and the material of the high-performance grouting material (8) is high-performance grouting material or polymer cement-based material.

6. A construction method for a prefabricated cap and pile foundation connection structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: A high-precision mold is used to prefabricate the prefabricated cap (1) and the pile foundation (2), and the connection hole (5) and the groove (7) are formed at one time during the mold making process to ensure that the connection components are accurately matched; The prefabricated cap (1) and pile foundation (2) are transported to the construction site by means of transport equipment, and the prefabricated cap (1) is aligned with the pile foundation (2) by means of lifting equipment so that the bolt hole (4) and the connection hole (5) are aligned; Pass the high-strength bolts (6) through the bolt holes (4) and the connection holes (5) in sequence, ensuring that each high-strength bolt (6) reaches the standard torque. After tightening, inject high-performance grouting material (8) into the groove (7), use a vibrating tool to ensure that the grouting is dense and has no gaps, and place the connection structure until the high-performance grouting material (8) solidifies; Check the overall verticality of the prefabricated foundation (1), use a laser measuring tool to ensure that the error is within the allowable range, test the torque value of the high-strength bolts (6) and the density of the grouting, and complete the quality acceptance.

7. The construction method according to claim 6, characterized in that: Before the hoisting equipment aligns the prefabricated cap (1) with the pile foundation (2), the position of the pile foundation (2) and the verticality and horizontality of the prefabricated cap (1) need to be calibrated by means of a laser measuring instrument or other positioning tools to ensure accurate alignment of the components during the assembly process.

8. The construction method according to claim 6, characterized in that: The method for ensuring that each high-strength bolt (6) reaches the standard torque is to use a torque wrench to tighten the high-strength bolts (6) one by one according to the size requirements of the standard torque.

9. The construction method according to claim 6, characterized in that: After the pile foundation (2) is prefabricated, an anti-corrosion treatment is performed on the surface of the pile foundation (2).

10. A simulation experiment method for a prefabricated cap and pile foundation connection structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: A three-dimensional model of a system composed of a prefabricated cap (1) and a pile foundation (2) is established using ABAQUS. The three-dimensional model includes a model of the prefabricated cap (1), a prefabricated pile foundation (2), a connector (3), a high-strength bolt (6), and a secondary grouting area for filling a high-performance grouting material (8). The material of the model adopts nonlinear material properties. Setting geometric parameters of the prefabricated cap (1), pile foundation (2) and connecting member (3), and setting material properties of the prefabricated cap (1), pile foundation (2), connecting member (3), high-strength bolts (6) and high-performance grouting material (8); Applying boundary conditions and loads to the three-dimensional model, wherein the boundary conditions include fixation of the bottom of the pile foundation (2) and friction force on the side of the pile foundation (2), and the loads include vertical loads, horizontal loads and dynamic working conditions; Perform static analysis, dynamic response analysis, fatigue life analysis, and result analysis and verification on 3D models with applied boundary conditions and loads.

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