Pile foundation underpinning construction of bridge pile cap side wall and construction method

Abstract

The application discloses a bearing platform side wall settlement reducing device and a construction method for bridge pile foundation underpinning construction, and relates to the field of bridge construction. The bearing platform side wall settlement reducing device and the construction method comprise a downward pressing component and an upward pulling component, the downward pressing component is fixed on a side wall of a foundation pit, the upward pulling component is fixed on a side wall of a bridge pier bearing platform, the downward pressing component and the upward pulling component are arranged in pairs, and a pair of downward pressing components and upward pulling components used in cooperation are engaged with each other. The bearing platform side wall settlement reducing device and the construction method prevent the bearing platform from sinking in the pile foundation underpinning jacking process through the engagement force between the downward pressing component and the upward pulling component.

Description

Technical Field

[0001] This invention relates to the field of bridge pile foundation replacement and jacking construction technology, specifically, to a pile cap sidewall settlement reduction device and construction method for bridge pile foundation replacement construction. Background Technology

[0002] With the rapid development of urban rail transit, the number of newly constructed tunnels passing under existing bridges is increasing. When the tunnel excavation section conflicts with the existing bridge pile foundation, it is necessary to replace the bridge foundation to ensure smooth tunnel construction and safe bridge operation. During the jacking process using single-pier or multi-pier replacement, it has been found that the end resistance or side friction of the replacement piles does not meet expectations, leading to pile subsidence and subsequently, pile cap subsidence, making it impossible to jack the existing piles to the required height for pile cutting. The current approach to this problem is to wait until the pile cap subsides and stabilizes, and then, based on experience, determine that there are no safety hazards, before proceeding with jacking. This approach, however, affects the construction progress and poses significant safety risks. Summary of the Invention

[0003] The purpose of this invention is to provide a pile cap sidewall settlement reduction device and construction method for bridge pile foundation replacement construction. The pile cap sidewall settlement reduction device and construction method prevent the pile cap from settling during the pile foundation replacement jacking process by using the interlocking force between the pressing component and the pulling component, without affecting the jacking process.

[0004] To achieve the above objectives, the present invention provides a settling reduction device for the side wall of a pier cap for bridge pile foundation replacement construction, comprising a pressing component and an upper pulling component. The pressing component is fixed to the side wall of the foundation pit, and the upper pulling component is fixed to the side wall of the pier cap. The pressing component and the upper pulling component are arranged in pairs, and the pair of pressing components and upper pulling components used in cooperation are interlocked with each other.

[0005] Preferably, the pressing component sequentially includes an outer steel plate, a rubber gasket, a connecting steel plate, and an inner steel plate. The outer side of the inner steel plate is provided with a plurality of pressing serrated strips, and a serrated groove is formed between two adjacent pressing serrated strips.

[0006] Preferably, all of the outer steel plates are symmetrically fixed to the sidewall of the foundation pit by the first bolt.

[0007] Preferably, the upper surface of the downward-pressing saw blade is a horizontal plane, and the lower surface of the downward-pressing saw blade is a second guide surface.

[0008] Preferably, the outer steel plate, rubber gasket, and connecting steel plate are assembled and connected by a plurality of second bolts.

[0009] Preferably, the upper pull member includes an outer steel plate and an inner steel plate in sequence. An upper pull saw tooth is provided on the outer side of the inner steel plate and mounted on the lower pressure saw tooth. A saw tooth-shaped upper groove is formed between two adjacent upper pull saw teeth.

[0010] Preferably, the outer steel plate is surrounded by multiple straight threaded steel bars, which are tied together with the steel cage inside the side wall of the pier abutment.

[0011] Preferably, the lower surface of the upper pull saw tooth is a horizontal plane, and the upper surface of the upper pull saw tooth is a first guide surface that cooperates with the second guide surface.

[0012] The present invention also provides a construction method for bridge pile foundation underpinning, using the aforementioned pile cap sidewall settlement reduction device, comprising the following steps: Step 201, Construction preparation and parameter calculation; Step 202: Tie straight threaded steel bars to the steel cage in the groove on the side of the foundation. Step 203, Foundation cap pouring and pit sidewall treatment; Step 204: Pre-assembly and on-site installation of the settlement reduction device for the foundation sidewall; Step 205: Pile foundation support and jacking construction; Step 206: Monitor the structural status; Step 207: The sedimentation protection device is activated; Step 208, subsequent construction.

[0013] The pier cap sidewall settlement reduction device of this invention has the following beneficial effects: 1. The lower pressing component and the upper pulling component are engaged by a sawtooth groove, which is convenient to install and does not require complex equipment, making it easy to carry out on-site construction; 2. The interlocking force between the lower pressing component and the upper pulling component can be used to directly resist the pier cap settlement caused by the settlement of the underpinning pile, effectively solving the problem of pier cap settlement during the jacking process, ensuring the pile cutting height requirement, and significantly improving construction safety and reliability; 3. The lower pressing component is equipped with a rectangular rubber gasket, which plays a flexible rebound role during the jacking process, which does not affect the normal jacking operation and can adaptively adjust the interlocking pressure, which is ingenious; 4. The number of devices and the specifications of high-strength bolts can be determined according to the load calculation of the pier cap and existing piles, adapting to different bridge conditions, with flexible design and sufficient safety redundancy; 5. The cost is low, the main components are steel plates, rubber gaskets and bolts, which are easy to process, and can effectively avoid technical stagnation or secondary treatment caused by pier cap settlement, greatly shortening the construction period and resulting in significant comprehensive economic benefits.

[0014] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the pressure member; Figure 2 This is a schematic diagram of the overall structure of a preferred embodiment of the pull-up member; Figure 3 This is a schematic diagram showing the installation location of the pull-up component; Figure 4 This is a schematic diagram of the installation position of the pressure component; Figure 5 This is a schematic diagram of the engagement between the pressing member and the pulling member; Figure 6 This is a schematic diagram illustrating the cooperation between the upper pull saw tooth and the lower press saw tooth of the present invention; Figure 7 This is a flowchart of the construction process of this invention.

[0016] Explanation of reference numerals in the attached figures 1-Side wall of the foundation pit; 2-First bolt; 3-Outer steel plate; 4-Rubber gasket; 5-Second bolt; 6-Connecting steel plate; 7-Lower pressure sawtooth; 8-Upper pull sawtooth; 9-Straight threaded steel bar; 10-Outer steel plate; 11-Side wall of the pier cap; 12-Inner steel plate; 13-Groove; 14-Reinforcing cage; 15-Inner steel plate; 16-Second guide surface; 17-First anti-slip surface; 18-Horizontal plane. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] In this invention, unless otherwise stated, directional terms such as "up, down, left, right, front, back, inside, outside" in the terminology only represent the orientation of the term in its normal use or are common terms understood by those skilled in the art, and should not be regarded as a limitation on the term.

[0019] See Figure 1-6 The shown pier cap sidewall settlement reduction device for bridge pile foundation replacement construction includes a lower pressing member and an upper pulling member. The lower pressing member is fixed to the pit sidewall 1, and the upper pulling member is fixed to the pier cap sidewall 11. The lower pressing member and the upper pulling member are arranged in pairs, and the pair of lower pressing members and upper pulling members used in cooperation are interlocked with each other.

[0020] By implementing the above technical solution, the pile cap sidewall settlement reduction device in this invention prevents the pile cap from settling during the pile foundation replacement and jacking process by using the interlocking force between the pressing component and the pulling component, thereby ensuring construction safety and the jacking process.

[0021] In one embodiment of the present invention, the combined structure of the pressing member and the pulling member is distributed around the pit sidewall 1 and the pier cap sidewall 11, and the adjacent spacing is consistent. The specific number of arrangements is determined according to the load of the cap and the existing piles, and they are arranged symmetrically on the left and right and front and back.

[0022] In this embodiment, the pressing component sequentially includes an outer steel plate 3, a rubber gasket 4, a connecting steel plate 6, and an inner steel plate 15. The outer side of the inner steel plate 15 is provided with a plurality of pressing serrated strips 7, and a serrated groove 13 is formed between two adjacent pressing serrated strips 7.

[0023] Furthermore, the upper pull member sequentially includes an outer steel plate 10 and an inner steel plate 12. An upper pull sawtooth 8 mounted on the lower pressure sawtooth 7 is provided on the outer side of the inner steel plate 12, and a sawtooth-shaped upper groove 13 is formed between two adjacent upper pull sawtooth 8.

[0024] When existing pile foundations of bridge piers need to be replaced, jacks placed in the replacement piles are used to lift the pier cap and cut off the existing piles. During the lifting process, if the pile end resistance or pile side friction of the replacement pile does not meet the expected effect, causing the replacement pile to sink, which in turn causes the pier cap to sink, this device can resist the sinking of the pier cap through the interlocking force between the multiple downward pressure sawtooth strips 7 of the downward pressure component and the upward pull sawtooth strips 8 of the upward pull component, without affecting the lifting process. The spacing of the sawtooth-shaped lower grooves 13 is consistent with the spacing of the sawtooth-shaped upper grooves 13, ensuring that the downward pressure sawtooth strips 7 can be engaged in the sawtooth-shaped upper grooves 13, and the upward pull sawtooth strips 8 can be engaged in the sawtooth-shaped lower grooves 13.

[0025] Among them, the outer steel plate 3, rubber gasket 4, connecting steel plate 6, inner steel plate 15, outer steel plate 10 and inner steel plate 12 are all rectangular structures. The rectangular rubber gasket 4 plays a rebound role when compressed, and the rebound force further ensures the stability of the engagement.

[0026] In this invention, the upper surface of the upward-pulling sawtooth 8 is provided with a first guide surface, and the lower surface is flat; the lower surface of the downward-pressing sawtooth 7 is provided with a second guide surface 16, and the upper surface is flat. During the downward pressing assembly process, the second guide surface 16 presses against the first guide surface, and the rubber pad 4 is compressed, causing the inner steel plate 15 to move laterally, thereby overcoming the obstruction of the upward-pulling sawtooth 8, so that multiple downward-pressing sawtooth 7 are inserted one by one into the sawtooth-shaped upper groove 13. After determining the position of the downward-pressing component, holes are drilled in the pit sidewall 1, and the downward-pressing component is fixed to the pit sidewall 1 by passing the outer steel plate 3 through the first bolt 2. That is, multiple outer steel plates 3 are symmetrically fixed to the pit sidewall 1 by the first bolt 2. The first bolt 2 is a high-strength bolt.

[0027] It should be noted that when installing the pressing component, the pressing serrated strip 7 of the pressing component must be misaligned and inserted into the serrated upper groove 13 of the fixed upper pull component, so that 4 to 5 empty slots are reserved above the serrated lower groove 13 of the pressing component to ensure proper assembly.

[0028] Before construction, the device of the present invention needs to determine the height to be lifted when cutting the pile foundation, so as to determine the number of sawtooth upper grooves 13 in the upper pull member and the number of layers of sawtooth lower grooves 13 on the lower press member, and the number should be more rather than less.

[0029] In this embodiment, the outer steel plate 3, the rubber gasket 4, and the connecting steel plate 6 are assembled and connected by a plurality of second bolts 5. The second bolts 5 are made of high-strength steel, and the outer steel plate 3, the rubber gasket 4, and the connecting steel plate 6 are assembled and connected by a plurality of second bolts 5 before the pressing component is installed.

[0030] In this invention, the connecting steel plate 6 and the inner steel plate 12 are welded together or integrally formed, and the outer steel plate 10 and the inner steel plate 12 are also welded together or integrally formed.

[0031] In this invention, the outer steel plate 10 is surrounded by multiple straight threaded steel bars 9, which are tied together with the reinforcing cage 14 inside the side wall 11 of the pier abutment. Before the lowering member is installed, the upper pulling member is installed first. The upper pulling member is tied to the reinforcing cage 14 by multiple circumferentially arranged straight threaded steel bars 9. After tying, the formwork of the abutment is poured to fix the multiple straight threaded steel bars 9. Then, the outer steel plate 10 is inserted into the pre-reserved section at the outer end of the straight threaded steel bar 9 and fixed by nuts or welding.

[0032] For example, if a shield tunnel for urban rail transit needs to pass under an existing overpass, and the original pile foundation of the bridge encroaches on the tunnel excavation section, multi-pier replacement construction is required. During the replacement process, to prevent the pier cap from sinking due to the settlement of the replacement piles, the settlement reduction protection device described in this invention is used for construction control.

[0033] like Figure 7 As shown, the present invention also provides a construction method for bridge pile foundation underpinning, using the aforementioned pile cap sidewall settlement reduction device, comprising the following steps: Step 201, Construction Preparation and Parameter Calculation: Specifically, based on the design drawings, the dimensions of the existing pier cap sidewall 11, the existing pile foundation load, and the preset jacking height required during pile cutting are determined. Based on the total load of the cap and existing pile foundation, mechanical calculations are used to determine the total number of settlement reduction protection devices required, the bearing capacity requirement of each device, and the number of layers of sawtooth grooves 13 on the lower pressure member and the upper tension member. The calculation follows the principle of "better too many than too few," ensuring that the number of groove layers 13 is not less than the theoretical number of layers corresponding to the jacking height. Simultaneously, the specifications and quantity of high-strength bolts and straight threaded steel bars 9 required to fix the lower pressure member and upper tension member are calculated to ensure that all connectors are symmetrically arranged to evenly distribute the load.

[0034] Step 202: Tie straight threaded steel bars 9 into the steel cage 14 inside the groove 13 on the side of the foundation. Specifically, before the foundation formwork is erected and the concrete is poured, the straight threaded steel bars 9, according to the specifications, quantity, and arrangement determined in step 201, are tied to the steel cage 14 of the foundation. During tying, it is necessary to ensure that the position of the straight threaded steel bars 9 precisely corresponds to the fixing holes of the subsequent upper tensioning members, and to reserve sufficient extension length for subsequent fixing of the upper tensioning members. The reserved length should be determined based on the thickness and fastening requirements of the upper tensioning members to ensure that the upper tensioning members can be firmly fixed within the groove 13 of the foundation sidewall.

[0035] Step 203, Foundation cap pouring and pit sidewall treatment: Specifically, after completing the binding of the reinforcing cage 14 and the pre-embedding of the straight threaded reinforcing bars 9, the formwork and pouring construction of the pier cap is carried out. During the pier cap design, a groove 13 of a certain depth must be reserved at the predetermined installation position on the side wall 11 of the pier cap. The depth of the groove 13 must be greater than the overall thickness of the settlement reduction protection device to meet the construction requirements for high-strength bolt fixing. After the pier cap is poured and reaches its design strength, the corresponding fixing positions on the side wall 1 of the foundation pit are cleaned and leveled to ensure that the surface of the side wall 1 of the foundation pit is flat and solid when the pressure component is installed, and can reliably bear the load transmitted by the pressure component.

[0036] Step 204, Pre-assembly and on-site installation of the settlement reduction device for the foundation sidewall: Specifically, the outer steel plate 3, rubber gasket 4, and connecting steel plate 6 of the lowering component are first assembled into a whole using high-strength bolts. Then, the upper pulling component is symmetrically fixed in the groove 13 reserved in the side wall 11 of the pier cap using the reserved straight threaded steel bars 9. Next, the lowering component is installed: the serrated groove 13 of the lowering component is staggered and inserted into the reverse serrated groove 13 of the fixed upper pulling component, and 4-5 empty slots are reserved above the serrated groove 13 of the lowering component to ensure proper assembly and reserve sufficient travel space for subsequent jacking. After determining the installation position of the lowering component, it is symmetrically fixed to the side wall 1 of the foundation pit using high-strength bolts. The entire device is set between the side wall 1 of the foundation pit and the side wall 11 of the pier cap. The specific number is determined according to the calculation results of step 201, and the spacing between each device is consistent, symmetrically arranged around the pier cap.

[0037] Step 205, Pile foundation support and jacking construction: Specifically, jacks are placed in the replacement piles to begin the pile foundation replacement and jacking operation. During the jacking process, the pier cap drives the upper pull member to rise slowly relative to the lower pressure member. Because the reverse sawtooth groove 13 of the upper pull member and the sawtooth groove 13 of the lower pressure member are misaligned and engaged, and a slot is reserved above, the upper pull member can move upward smoothly without being obstructed by the lower pressure member. At the same time, the rectangular rubber pad 4 in the lower pressure member plays a rebound role during the jacking process, which can ensure stable contact of the interlocking surfaces without affecting the normal jacking operation.

[0038] Step 206, Monitor structural status: Throughout the jacking process, the structural condition was monitored in real time through displacement and stress monitoring points placed on the pile cap, replacement piles, and existing bridge. Monitoring included the vertical and horizontal displacement of the pile cap, the settlement of the replacement piles, the deformation of the existing bridge, and the stress state of each settlement mitigation protection device. Real-time monitoring data was used to determine whether the jacking process was smooth and whether there were any abnormal settlement trends in the pile cap, providing data support for construction safety.

[0039] Step 207, the settling protection device is activated: If, during the jacking process, the pile end resistance or pile side friction of the replacement pile does not achieve the expected effect, causing the replacement pile and the pile cap to show an unexpected downward trend, the pull-up component will move downward with the pile cap.

[0040] At this point, the reverse serrated groove 13 of the upper tension member and the serrated groove 13 of the lower pressure member cannot disengage due to their reverse interlocking, forming a strong interlocking force. This interlocking force directly resists the sinking force of the pile cap, stabilizing the pile cap in its current position and preventing it from sinking further. Through this one-way self-locking mechanism, the device ensures that the pile cap can be smoothly lifted but cannot sink, thus providing a reliable safety guarantee for the pile foundation replacement and lifting construction. The rectangular rubber gasket 4 further provides flexible rebound when the device is under pressure, ensuring the continuous stability of the interlocking state.

[0041] Step 208, subsequent construction: After the existing pile foundations are removed and the new pile foundations are stable under stress, the subsequent system conversion work is carried out in an orderly manner according to the construction plan. The existing piles can only be cut off after confirming that the jacking height has reached the preset value required for pile cutting and that the structural deformation is stable. After pile cutting is completed, the load is gradually transferred to the new pile foundations according to design requirements, completing the entire pile foundation replacement process. After the entire replacement construction is completed and the structural stability is confirmed by monitoring data, the settlement reduction protection device can be removed for reuse in subsequent similar projects.

[0042] The application results of this invention show that the abutment sidewall settlement reduction protection device for bridge pile foundation replacement construction has a reasonable structural design and is easy to install. Through the interlocking force between the groove 13 of the lower pressing component and the reverse sawtooth of the upper pulling component, it can effectively resist the sinking trend of the abutment during the replacement and jacking process, ensure the stability of the jacking height, and avoid the problem of not being able to cut off the existing piles due to the sinking of the abutment. The device does not affect the normal jacking of the abutment, significantly improves the safety and reliability of construction, and has significant comprehensive economic benefits.

[0043] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A settlement reduction device for the sidewall of a bridge pile foundation used in bridge pile foundation replacement construction, characterized in that, It includes a lower pressing member and an upper pulling member. The lower pressing member is fixed to the side wall of the foundation pit (1), and the upper pulling member is fixed to the side wall of the pier cap (11). The lower pressing member and the upper pulling member are arranged in pairs, and the pair of lower pressing members and upper pulling members used together are interlocked with each other.

2. The settlement reduction device for the side wall of the bridge pile foundation underpinning construction according to claim 1, characterized in that, The pressing component includes, in sequence, an outer steel plate (3), a rubber gasket (4), a connecting steel plate (6), and an inner steel plate (15). The outer side of the inner steel plate (15) is provided with a plurality of downward pressure serrated strips (7), and a serrated groove (13) is formed between two adjacent downward pressure serrated strips (7).

3. The settlement reduction device for the side wall of the bridge pile foundation underpinning construction according to claim 2, characterized in that, Multiple outer steel plates (3) are symmetrically fixed to the pit sidewall (1) by first bolts (2).

4. The settlement reduction device for the side wall of the bridge pile foundation underpinning construction according to claim 2, characterized in that, The upper surface of the downward pressing saw blade (7) is a horizontal plane (18), and the lower surface of the downward pressing saw blade (7) is a second guide surface (16).

5. The settling reduction device for the sidewall of a bridge pile foundation underpinning construction according to claim 2, characterized in that, The outer steel plate (3), rubber gasket (4) and connecting steel plate (6) are assembled and connected by a plurality of second bolts (5).

6. The settlement reduction device for the sidewall of a bridge pile foundation underpinning construction according to any one of claims 2-5, characterized in that, The upper pull member includes an outer steel plate (10) and an inner steel plate (12) in sequence. An upper pull sawtooth (8) mounted on the lower pressure sawtooth (7) is provided on the outer side of the inner steel plate (12). A sawtooth-shaped upper groove (13) is formed between two adjacent upper pull sawtooths (8).

7. The settling reduction device for the sidewall of a bridge pile foundation underpinning construction according to claim 6, characterized in that, The outer steel plate (10) is surrounded by a plurality of straight threaded steel bars (9), which are tied together with the steel cage (14) inside the side wall (11) of the pier abutment.

8. The settling reduction device for the side wall of the bridge pile foundation underpinning construction according to claim 6, characterized in that, The lower surface of the upper pull saw tooth (8) is a horizontal surface (18), and the upper surface of the upper pull saw tooth (8) is a first guide surface that cooperates with the second guide surface (16).

9. A construction method for bridge pile foundation underpinning, using the pile cap sidewall settlement reduction device according to any one of claims 1-8, comprising the following steps: Step 201, Construction preparation and parameter calculation; Step 202: Tie straight threaded steel bars (9) in the steel cage (14) in the groove (13) on the side of the foundation. Step 203, foundation cap casting and pit sidewall (1) treatment; Step 204: Pre-assembly and on-site installation of the settlement reduction device for the foundation sidewall; Step 205: Pile foundation support and jacking construction; Step 206: Monitor the structural status; Step 207: The sedimentation protection device is activated; Step 208, subsequent construction.

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