Temporary pile foundation under railway replacement construction method

Abstract

The application discloses a railway-under temporary pile foundation underpinning construction method, and belongs to the technical field of road construction under railways. The railway-under temporary pile foundation underpinning construction method comprises the following steps: S1, symmetrically arranging underpinning pile groups on opposite sides of a foundation structure; each underpinning pile group comprises two underpinning piles, and the two underpinning piles in the same group are symmetrically arranged with the railway center line as an axis; S2, mounting underpinning beams on the two underpinning piles on the same side of the railway along the extension direction of the railway; S3, uniformly arranging a plurality of connecting beams at the lower ends of the two underpinning beams along the extension direction of the railway; S4, arranging wedge adjusting devices between the underpinning piles and the underpinning beams; S5, performing a staged and balanced cutting operation on the existing foundation structure, and adjusting the wedge adjusting devices to compensate for the deformation and settlement deviation of the underpinning beams; and S6, performing railway-under construction. The application can effectively control the settlement and deviation, perform pile foundation underpinning construction under the condition of ensuring the construction efficiency, and guarantee the stability of railway operation.

Description

Technical Field

[0001] This invention relates to the field of road construction technology for underpass railways, and in particular to a method for temporary pile foundation replacement construction under railways. Background Technology

[0002] With the densification of urban rail transit networks and the increasing density of existing buildings, the demand for tunnel projects to pass under existing bridges, viaducts, railways, and other pile foundation structures has increased significantly. For railway-related projects, direct construction requires stopping railway operations and may even damage existing railway lines. Therefore, to minimize the impact of underpass construction on existing railway operations and ensure the continuous, stable, and safe operation of the railway during construction, temporary pile foundation replacement is often necessary.

[0003] The principle of pile replacement is essentially to replace the existing load-bearing system with a completely new one. Ensuring a smooth and safe replacement of the load-bearing system is the key and challenging aspect of the construction process. In traditional railway pile foundation replacement construction, the construction of the replacement piles is usually carried out on both sides of the pile to be replaced first, followed by the casting of the integral cast-in-place replacement beam. Subsequent construction can only proceed after the settlement of the replacement system has stabilized. However, the construction of the cast-in-place replacement beam requires on-site formwork and has a long curing time, which undoubtedly occupies a significant portion of the railway's maintenance window. Furthermore, when removing the original pile foundation, if local settlement or displacement occurs, the lack of efficient manual adjustment methods makes it difficult to respond quickly, potentially threatening the stable operation of the railway. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for temporary pile foundation replacement construction under railways, which can effectively control settlement and displacement, carry out pile foundation replacement construction while ensuring construction efficiency, and ensure the stability of railway operation.

[0005] According to an embodiment of the present invention, a method for constructing temporary pile foundation replacement under railway includes: S1: determining the replacement range of the existing foundation structure, and symmetrically arranging replacement pile groups on opposite sides of the foundation structure along the extension direction of the railway. Each replacement pile group contains two replacement piles, and the two replacement piles in the same group are arranged in a mirror image with the railway centerline as the axis.

[0006] S2: After all the replacement piles have settled and stabilized, install replacement beams along the railway extension direction on two replacement piles located on the same side of the railway so that the replacement beams on both sides of the railway are parallel to the railway.

[0007] S3: Along the extension direction of the railway, multiple connecting beams are evenly distributed at the lower end of the two supporting beams, and the upper end of each connecting beam abuts against the bottom of the railway. The two supporting beams and multiple connecting beams are connected to each other to form a support frame.

[0008] S4: A wedge adjustment device is installed between the replacement pile and the replacement beam so that each replacement pile can be in close contact with the corresponding replacement beam through the wedge adjustment device;

[0009] S5: Perform phased and balanced severing operations on the existing foundation structure. After each phase of severing is completed, allow it to stand for a preset time and monitor the deformation and settlement data of the replacement beam simultaneously. Adjust the wedge adjustment device to compensate for the deformation and settlement deviation of the replacement beam.

[0010] S6: After the railway load has been completely transferred from the existing foundation structure to the underpass system consisting of underpass beams and underpass piles, the underpass construction will proceed.

[0011] The railway temporary pile foundation replacement construction method according to embodiments of the present invention has at least the following beneficial effects: Firstly, by symmetrically arranging replacement pile groups and precast replacement beams along the railway centerline to form a stable support frame, and using connecting beams to strengthen the overall integrity, the method ensures uniform load transfer while avoiding on-site formwork and long curing periods for cast-in-place beams, significantly shortening the railway maintenance window period. Secondly, by introducing a wedge adjustment device between the replacement beam and the replacement pile, the connection state between the replacement beam and the pile is dynamically adjusted through monitoring data, actively compensating for settlement deviations, and achieving an adjustable connection between the replacement beam and the replacement pile. Combined with phased cutoff and static monitoring, the load is gradually transferred from the original pile foundation to the new system, forming a "monitoring-feedback-correction" closed loop with the wedge adjustment, thereby achieving a smooth transition of the stress system, improving construction efficiency while reducing railway operation risks.

[0012] According to some embodiments of the present invention, in S1, two steel plate supports are provided between each replacement pile and the corresponding replacement beam. One steel plate support is provided at the top of the replacement pile, and the other steel plate support is provided at the bottom of the corresponding replacement beam. The wedge adjustment device is connected to the two steel plate supports respectively. The steel plate supports are configured to cooperate with the wedge adjustment device to adjust the distance between the replacement beam and the replacement pile.

[0013] According to some embodiments of the present invention, in S1, the replacement pile group is spaced 30m to 50m apart from the existing foundation structure.

[0014] According to some embodiments of the present invention, in S4, the wedge adjustment device includes four wedge structures, with one wedge structure inserted between each supporting pile and the corresponding supporting beam, and the wedge structure is configured to perform millimeter-level elevation adjustment of the supporting beam.

[0015] According to some embodiments of the present invention, the wedge structure includes two wedges, which are symmetrically inserted between the supporting pile and the supporting beam along the center line of the corresponding supporting beam.

[0016] According to some embodiments of the present invention, the wedge adjustment device further includes: a drive module connected to the wedge, the drive module being used to drive the wedge structure to adjust the distance between the supporting beam and the supporting pile; a locking module, one of the wedge and the drive module being connected to the locking module, the locking module being used to lock the adjusted wedge between the supporting beam and the supporting pile; a data acquisition module connected to both the wedge and the drive module, the data acquisition module being used to monitor displacement parameters, mechanical parameters, and environmental parameters in real time; and a control module connected to the drive module, the locking module, and the data acquisition module, the control module being used to receive data acquired by the data acquisition module to control the operation of the drive module and the locking module.

[0017] According to some embodiments of the present invention, in S5, adjusting the wedge adjustment device to compensate for the deformation and settlement deviation of the replacement beam includes: the acquisition module acquiring the settlement value at the end of the replacement beam, the wedge contact pressure value, the ambient vibration frequency, and the replacement beam temperature value; the control module acquiring the settlement difference value between each corner of the support frame based on the settlement value at the end of the replacement beam, and the control module controlling the drive module to perform a first displacement adjustment on the wedge corresponding to the maximum settlement point in the support frame based on the settlement difference value; the control module verifying the effectiveness of settlement compensation based on the wedge contact pressure value, and the control module controlling the drive module to perform a second displacement adjustment on the wedge based on the verification result; the control module acquiring the characteristic frequency when the train passes based on the ambient vibration frequency, and the control module controlling the drive module to perform a third displacement adjustment on the wedge based on the characteristic frequency; and the control module acquiring the temperature difference between the real-time temperature of the replacement beam and the installation reference temperature based on the replacement beam temperature value, and the control module controlling the drive module to perform a fourth displacement adjustment on the wedge based on the temperature difference.

[0018] According to some embodiments of the present invention, the acquisition module includes four settlement acquisition units, each embedded at the end of the supporting beam. The settlement acquisition units are used to acquire the settlement value at the corresponding end of the supporting beam. The control module controls the drive module to perform a first displacement adjustment on the wedge corresponding to the maximum settlement point in the support frame based on the settlement difference value. This includes: acquiring real-time settlement difference values ​​between the corners of the support frame; when the real-time settlement difference value is greater than or equal to a first preset settlement difference value, the control module determines that the load distribution of the supporting beam is misaligned; the control module calculates a first settlement compensation amount based on the real-time settlement difference value; and the control module controls the drive module to adjust the displacement of the wedge at the maximum settlement point based on the first compensation amount. The wedges at the corresponding positions are adjusted until the settlement difference between the corners of the support frame is less than the first preset settlement difference value. When the real-time settlement difference value is less than the first preset settlement difference value, it is determined whether the real-time settlement value at the end of the replacement beam is greater than the second preset settlement difference value. When the real-time settlement value at the end of the replacement beam is greater than the second preset settlement difference value, the control module calculates the second compensation amount based on the real-time settlement value at the end of the replacement beam, and the control module controls the drive module to perform wedge adjustment according to the second settlement compensation amount on the wedges at the end of the replacement beam. Otherwise, the control module determines that the load distribution of the replacement beam is reasonable, and the control module controls the locking module to perform locking on the wedges.

[0019] According to some embodiments of the present invention, the acquisition module further includes eight contact pressure acquisition units. Each contact surface of the wedge is provided with a corresponding contact pressure acquisition unit. The contact pressure acquisition unit is used to acquire the contact pressure of the corresponding wedge. The control module controls the drive module to perform a second displacement adjustment on the wedge according to the verification result, including: acquiring the real-time contact pressure of the wedge; when the real-time contact pressure of the wedge is less than a first preset contact pressure value, the control module determines that the contact between the wedge and the support beam has failed, and the control module controls the drive module to continue to perform the wedge adjustment process until the settlement value of the support beam reaches the first preset contact pressure value; otherwise, the control module determines that the contact between the wedge and the support beam is successful, and the control module controls the locking module to perform a locking process on the wedge.

[0020] According to some embodiments of the present invention, the acquisition module further includes two environmental vibration acquisition units. Each supporting beam has an environmental vibration acquisition unit at its lower edge. The environmental vibration acquisition unit is used to acquire the characteristic frequency of the train passing by. The control module controls the drive module to perform a third displacement adjustment on the wedge according to the characteristic frequency, including: acquiring the real-time environmental vibration frequency; confirming whether the wedge meets the vibration loosening condition according to the environmental vibration frequency; when the environmental vibration frequency is greater than the preset vibration frequency, the control module determines that the wedge meets the vibration loosening condition, the control module generates a dynamic load compensation amount according to the environmental vibration frequency, and the control module controls the drive module to perform wedge adjustment processing according to the dynamic load compensation amount until the real-time contact pressure of the wedge meets the second preset contact pressure value; otherwise, it is determined that the wedge does not meet the vibration loosening condition, and the control module controls the locking module to perform locking processing on the wedge.

[0021] According to some embodiments of the present invention, the acquisition module further includes two temperature acquisition units. Each support beam has a temperature acquisition unit on its upper edge. The temperature acquisition unit is used to acquire the surface temperature of the support beam. The control module controls the drive module to perform a fourth displacement adjustment on the wedge according to the temperature difference, including: acquiring the real-time temperature of the support beam and the installation reference temperature; acquiring the temperature change value of the support beam according to the real-time temperature and the installation reference temperature; when the temperature change value is greater than the preset temperature change value, the control module determines that the support beam has a displacement error, acquires the linear expansion coefficient and the original length of the support beam, acquires the thermal deformation compensation amount according to the linear expansion coefficient, the original length of the support beam and the temperature change value of the support beam, and controls the drive module to perform wedge adjustment processing according to the thermal deformation compensation amount; otherwise, it is determined that the support beam has not generated a displacement error, and the control module controls the locking module to perform locking processing on the wedge.

[0022] According to some embodiments of the present invention, the drive module includes eight drive units, each wedge is provided with one drive unit, and each drive unit is provided with a vibration auxiliary unit. The vibration auxiliary unit is configured to disrupt the static friction of the wedge contact surface to ensure smooth advance and retraction of the wedge. The wedge adjustment process includes: acquiring the real-time operating current of the drive unit, and confirming whether the wedge is difficult to drive based on the real-time operating current; when the calculated driving resistance is greater than a preset resistance threshold, the control module determines that the friction resistance suppression step condition is met, and the control module controls the corresponding auxiliary unit to vibrate and assist the wedge advance; otherwise, if the friction resistance suppression step condition is not met, the control module generates an auxiliary sleep signal, and the control module adjusts the auxiliary unit to sleep mode according to the auxiliary sleep signal.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a flowchart illustrating a temporary pile foundation replacement construction method for railways according to a specific embodiment.

[0026] Figure 2 This is a structural schematic diagram of a temporary pile foundation replacement construction method for railways according to a specific embodiment;

[0027] Figure 3 for Figure 2 Top view;

[0028] Figure 4 for Figure 2 Schematic diagram of the connection between the central support pile, the support beam, and the inclined wedge;

[0029] Figure 5 for Figure 4 A schematic diagram showing the connection of the central support pile, the support beam, and the inclined wedge adjustment device.

[0030] Figure label:

[0031] 100mm of replacement piles and 110mm of steel plate supports;

[0032] Replacement beam 200;

[0033] Contact Liang 300;

[0034] Wedge adjustment device 400, wedge 410, drive module 420, fixing base 430;

[0035] 10 rails, 20 existing pile foundations, and 30 high-strength bolts. Detailed Implementation

[0036] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0037] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, and "above," "below," "within," etc. are understood to include the stated number. If "first," "second," etc. are used in the description, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0038] In the description of this invention, unless otherwise explicitly defined, terms such as "set", "install", and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0039] Please refer to Figure 1 This embodiment discloses a method for temporary pile foundation replacement construction under railways, including:

[0040] S1: Determine the scope of the existing foundation structure and symmetrically arrange 100 sets of replacement piles on opposite sides of the foundation structure along the extension direction of the railway. Each set of 100 replacement piles contains two replacement piles 100. The two replacement piles 100 in the same set are arranged in a mirror image with the railway centerline as the axis.

[0041] S2: After all the replacement piles 100 have settled and stabilized, install replacement beams 200 on the two replacement piles 100 located on the same side of the railway along the railway extension direction so that the replacement beams 200 on both sides of the railway are parallel to the railway.

[0042] S3: Along the extension direction of the railway, multiple connecting beams 300 are evenly distributed at the lower end of the two supporting beams 200, and the upper end of each connecting beam 300 is abutted against the bottom of the railway. The two supporting beams 200 and the multiple connecting beams 300 are connected to each other to form a support frame.

[0043] S4: A wedge adjustment device 400 is provided between the replacement pile 100 and the replacement beam 200 so that each replacement pile 100 can be in close contact with the corresponding replacement beam 200 through the wedge adjustment device 400.

[0044] S5: Perform phased balanced severing operations on the existing foundation structure. After each phase of severing is completed, allow it to stand for a preset time and simultaneously monitor the deformation and settlement data of the support beam 200. Adjust the wedge adjustment device 400 to compensate for the deformation and settlement deviation of the support beam 200.

[0045] S6: After the railway load is completely transferred from the existing foundation structure to the underpass system consisting of the underpass beam 200 and the underpass pile 100, the underpass construction will be carried out.

[0046] like Figure 2 , Figure 3 and Figure 4As shown, a stable support frame is formed by symmetrically arranging 100 sets of replacement piles and precast replacement beams 200 along the railway centerline. Connecting beams 300 reinforce the overall integrity, ensuring uniform load distribution while avoiding on-site formwork and long curing periods for cast-in-place beams, significantly shortening the railway maintenance window. Secondly, a wedge adjustment device 400 is introduced between the replacement beams 200 and the replacement piles 100. Monitoring data dynamically adjusts the connection between the replacement beams 200 and the piles, actively compensating for settlement deviations to ensure precise settlement of the replacement beams 200. The adjustable connection between the replacement beams 200 and the replacement piles 100, combined with phased cutoff and static monitoring, gradually transfers the load from the original pile foundation to the new system, forming a "monitoring-feedback-correction" closed loop. This achieves a smooth transition of the load-bearing system, improving construction efficiency while reducing railway operational risks.

[0047] It should be noted that in this specific embodiment, the replacement beam 200 is an I-beam. The replacement beam 200 is connected to the replacement pile 100 and the connecting beam 300 respectively by high-strength bolts 30. The modular assembly of the steel structure significantly shortens the construction period compared to traditional concrete replacement construction, thereby reducing the impact on the normal operation of the railway. Furthermore, after the railway underpass construction is completed, the entire pile foundation replacement system can be dismantled, and the dismantled I-beams can be reused, thus reducing material waste and construction debris, and greatly saving construction costs.

[0048] In some specific embodiments of the present invention, two steel plate supports 110 are provided between each replacement pile 100 and the corresponding replacement beam 200. One steel plate support 110 is located at the top of the replacement pile 100, and the other steel plate support 110 is located at the bottom of the corresponding replacement beam 200. A wedge adjustment device 400 is connected to each of the two steel plate supports 110, and the steel plate supports 110 are configured to cooperate with the wedge adjustment device 400 to adjust the distance between the replacement beam 200 and the replacement pile 100. Figure 4 and Figure 5 As shown, the steel plate support 110 serves as a high-rigidity transition layer, evenly distributing the load transmitted by the replacement beam 200 and preventing localized stress concentration from damaging the piles or beams. On the other hand, the wedge adjustment device 400 includes four wedge structures. Each replacement pile 100 and its corresponding replacement beam 200 is connected by a wedge structure, comprising two wedges 410. These two wedges 410 are symmetrically inserted between the replacement pile 100 and the replacement beam 200 along the centerline of the corresponding replacement beam 200. The wedges 410 are configured to perform millimeter-level elevation adjustments on the replacement beam 200. Thus, by changing the vertical height through the axial displacement of the wedges, and in conjunction with the flat contact surface of the steel plate support 110, millimeter-level precise adjustment of the distance between the replacement beam 200 and the replacement pile 100 is achieved, thereby compensating for settlement or deformation deviations during construction.

[0049] In some specific embodiments of the present invention, such as Figure 2 As shown, in S1, the spacing between the 100 sets of replacement piles and the existing foundation structure is 30m to 50m. It should be noted that this spacing range ensures that the 100 sets of replacement piles form a reasonable load-bearing span in the longitudinal direction of the railway. This avoids both excessive spacing leading to excessive bending moment at mid-span of the replacement beam 200 and insufficient spacing causing pile redundancy and construction waste. Furthermore, the 30m to 50m interval effectively avoids the stress diffusion zone of the existing pile foundation 20, reduces the superposition of soil disturbance between the old and new pile foundations, and maintains ground stability.

[0050] In some specific embodiments of the present invention, the wedge adjustment device 400 further includes: a drive module 420 connected to the wedge 410, the drive module 420 being used to drive the wedge structure to adjust the distance between the support beam 200 and the support pile 100; a locking module, one of the wedge 410 and the drive module 420 being connected to the locking module, the locking module being used to lock the adjusted wedge 410 between the support beam 200 and the support pile 100; a data acquisition module connected to both the wedge 410 and the drive module 420, the data acquisition module being used to monitor displacement parameters, mechanical parameters, and environmental parameters in real time; and a control module connected to the drive module 420, the locking module, and the data acquisition module, the control module being used to receive data acquired by the data acquisition module to control the actions of the drive module 420 and the locking module.

[0051] In some specific embodiments of the present invention, in S5, adjusting the wedge adjustment device 400 to compensate for the deformation and settlement deviation of the support beam 200 includes: the acquisition module acquiring the settlement value at the end of the support beam 200, the contact pressure value of the wedge 410, the ambient vibration frequency, and the temperature value of the support beam 200; the control module acquiring the settlement difference value between each corner of the support frame based on the settlement value at the end of the support beam 200, and the control module controlling the drive module 420 to perform a first displacement adjustment on the wedge 410 corresponding to the maximum settlement point in the support frame based on the settlement difference value; the control module according to The contact pressure value of the wedge 410 verifies the effectiveness of settlement compensation. The control module controls the drive module 420 to perform a second displacement adjustment on the wedge 410 based on the verification result. The control module obtains the characteristic frequency when the train passes by based on the environmental vibration frequency. The control module controls the drive module 420 to perform a third displacement adjustment on the wedge 410 based on the characteristic frequency. The control module obtains the temperature difference between the real-time temperature of the replacement beam 200 and the installation reference temperature based on the temperature value of the replacement beam 200. The control module controls the drive module 420 to perform a fourth displacement adjustment on the wedge 410 based on the temperature difference.

[0052] By constructing a multi-parameter collaborative intelligent control system, comprehensive dynamic compensation control of the underpinning system was achieved. Specifically, firstly, multi-source data fusion technology was employed, using a sensor network including settlement monitoring, contact pressure detection, environmental vibration sensing, and temperature measurement to acquire the system's state parameters in real time. Secondly, based on a hierarchical control strategy, dedicated compensation algorithms were designed for different types of disturbances. Finally, through a closed-loop feedback mechanism, the monitoring data was compared with preset thresholds, automatically generating precise adjustment commands to drive the 410 wedge device to complete millimeter-level fine-tuning. Thus, through 24-hour uninterrupted monitoring, control, and automatic compensation, structural deformation was controlled within 1mm, significantly reducing construction risks. Furthermore, the control module can intelligently identify and respond to the influence of multiple factors such as static load, dynamic load, and temperature, ensuring the reliability of the underpinning system under various environmental conditions. This has significant socio-economic value.

[0053] In some specific embodiments of the present invention, the acquisition module includes four settlement acquisition units. Each end of the supporting beam 200 is embedded with a settlement acquisition unit. The settlement acquisition unit is used to acquire the settlement value of the corresponding end of the supporting beam 200. The control module controls the drive module 420 to perform a first displacement adjustment on the wedge 410 corresponding to the maximum settlement point in the support frame based on the settlement difference value. This includes: acquiring the real-time settlement difference value between each corner of the support frame; when the real-time settlement difference value is greater than or equal to a first preset settlement difference value, the control module determines that the load distribution of the supporting beam 200 is imbalanced; the control module calculates a first settlement compensation amount based on the real-time settlement difference value; and the control module controls the drive module 420 to adjust the wedge 410 corresponding to the maximum settlement point based on the first compensation amount. 410 performs wedge adjustment until the settlement difference between each corner of the support frame is less than the first preset settlement difference value. When the real-time settlement difference value is less than the first preset settlement difference value, it is determined whether the real-time settlement value at the end of the replacement beam 200 is greater than the second preset settlement difference value. When the real-time settlement value at the end of the replacement beam 200 is greater than the second preset settlement difference value, the control module calculates the second compensation amount based on the real-time settlement value at the end of the replacement beam 200. The control module controls the drive module 420 to perform wedge adjustment according to the second settlement compensation amount at the wedge 410 at the end of the replacement beam 200. Otherwise, the control module determines that the load distribution of the replacement beam 200 is reasonable, and the control module controls the locking module to perform locking on the wedge 410.

[0054] The specific calculation process is expressed by the following formula:

[0055]

[0056] in, This is the first settlement compensation amount. The settlement sensitivity coefficient is set at 1.2-1.5. The maximum settlement value is the settlement value at the settlement point. The average settlement value. This is the constant for elastic deformation compensation.

[0057]

[0058] in, This is the second settlement compensation amount. The correction factor is set to 0.8-1.2. To support the replacement beam with a span of 200, This represents the current settlement value at the measuring point. The allowable settlement value.

[0059] In some specific embodiments of the present invention, the acquisition module further includes eight contact pressure acquisition units. Each contact surface of the wedge 410 is provided with a corresponding contact pressure acquisition unit. The contact pressure acquisition unit is used to acquire the contact pressure of the corresponding wedge 410. The control module controls the drive module 420 to perform a second displacement adjustment on the wedge 410 according to the verification result, including: acquiring the real-time contact pressure of the wedge 410; when the real-time contact pressure of the wedge 410 is less than the first preset contact pressure value, the control module determines that the contact between the wedge 410 and the support beam 200 has failed, and the control module controls the drive module 420 to continue to perform the wedge 410 adjustment process until the settlement value of the support beam 200 reaches the first preset contact pressure value; otherwise, the control module determines that the contact between the wedge 410 and the support beam 200 is successful, and the control module controls the locking module to perform a locking process on the wedge 410.

[0060] The specific calculation process is expressed by the following formula:

[0061]

[0062] in, To effectively contact pressure, To measure the contact pressure, The coefficient of friction is taken to be 0.15-0.25. The inclination angle is 410°.

[0063] In some specific embodiments of the present invention, the acquisition module further includes two environmental vibration acquisition units. Each supporting beam 200 has an environmental vibration acquisition unit at its lower edge. The environmental vibration acquisition unit is used to acquire the characteristic frequency of the train passing by. The control module controls the drive module 420 to perform a third displacement adjustment on the wedge 410 according to the characteristic frequency, including: acquiring the real-time environmental vibration frequency; confirming whether the wedge 410 meets the vibration loosening condition according to the environmental vibration frequency; when the environmental vibration frequency is greater than the preset vibration frequency, the control module determines that the wedge 410 meets the vibration loosening condition, the control module generates a dynamic load compensation amount according to the environmental vibration frequency, and the control module controls the drive module 420 to perform wedge 410 adjustment processing according to the dynamic load compensation amount until the real-time contact pressure of the wedge 410 meets the second preset contact pressure value; otherwise, it is determined that the wedge 410 does not meet the vibration loosening condition, and the control module controls the locking module to perform locking processing on the wedge 410.

[0064] The specific calculation process is expressed by the following formula:

[0065]

[0066] in, This is the amount of dynamic load compensation. The vibration response coefficient is taken as 0.05-0.1. To measure the vibration frequency, The natural frequency of the structure, This represents the amplitude of the vibration acceleration.

[0067] In some specific embodiments of the present invention, the acquisition module further includes two temperature acquisition units. Each support beam 200 has a temperature acquisition unit on its upper edge. The temperature acquisition unit is used to acquire the surface temperature of the support beam 200. The control module controls the drive module 420 to perform a fourth displacement adjustment on the wedge 410 according to the temperature difference, including: acquiring the real-time temperature of the support beam 200 and the installation reference temperature; acquiring the temperature change value of the support beam 200 according to the real-time temperature and the installation reference temperature; when the temperature change value is greater than the preset temperature change value, the control module determines that the support beam 200 has a displacement error, acquires the linear expansion coefficient of the support beam 200 and the original length of the support beam 200, acquires the thermal deformation compensation amount according to the linear expansion coefficient of the support beam 200, the original length of the support beam 200 and the temperature change value of the support beam 200, and the control module controls the drive module 420 to perform wedge 410 adjustment processing according to the thermal deformation compensation amount; otherwise, it is determined that the support beam 200 has not generated a displacement error, and the control module controls the locking module to perform locking processing on the wedge 410.

[0068] The specific calculation process is expressed by the following formula:

[0069]

[0070] in, This is the amount of thermal deformation compensation. The coefficient of linear expansion is 1 / 3. The length of the beam. For temperature difference, The creep compensation coefficient is set to 0.0002-0.0005.

[0071] In some specific embodiments of the present invention, the drive module 420 includes eight drive units, each wedge 410 is provided with a corresponding drive unit, and each drive unit is provided with a corresponding vibration auxiliary unit. The vibration auxiliary unit is configured to disrupt the static friction of the contact surface of the wedge 410 to ensure that the wedge 410 advances and retracts smoothly. The wedge 410 adjustment process includes: acquiring the real-time operating current of the drive unit, and confirming whether the wedge 410 is difficult to drive based on the real-time operating current; when the calculated driving resistance is greater than the preset resistance threshold, the control module determines that the friction resistance suppression step condition is met, and the control module controls the corresponding auxiliary unit to vibrate and assist the wedge 410 in advancing; otherwise, if the friction resistance suppression step condition is not met, the control module generates an auxiliary sleep signal, and the control module adjusts the auxiliary unit to sleep mode according to the auxiliary sleep signal.

[0072] The specific calculation process is expressed by the following formula:

[0073]

[0074] in, The driving resistance is for the 410-degree wedge. To measure the actual operating current, This is the no-load current. The torque constant of the motor. The transmission efficiency is set to 0.85-0.95.

[0075] When the following conditions are met Vibration assistance is activated at the appropriate time;

[0076] in, The static friction coefficient is For normal force, The frequency is the vibration frequency.

[0077] The following specific examples illustrate the construction method for temporary pile foundation replacement under this railway.

[0078] A railway trunk line needs to construct an underpass tunnel, and the pile foundations of the existing railway bridges need to be replaced to ensure the stability of the railway line during tunnel excavation.

[0079] S1: Determine the scope of the existing foundation structure and symmetrically arrange 100 sets of replacement piles on opposite sides of the foundation structure along the extension direction of the railway. Each set of 100 replacement piles contains two replacement piles 100. The two replacement piles 100 in the same set are arranged in a mirror image with the railway centerline as the axis.

[0080] like Figure 2 As shown, with the railway extension direction as the front and rear direction, 100 sets of replacement piles are symmetrically arranged on both the front and rear sides of the existing pile foundation 20. Each set contains two bored cast-in-place piles, with a pile spacing of 30m. Steel plate supports 110 are pre-embedded at the top of the replacement piles 100 and the bottom of the replacement beam 200. The steel plates are 30mm thick and the surface is treated with anti-rust treatment.

[0081] S2: After all the replacement piles 100 have settled and stabilized, install replacement beams 200 on the two replacement piles 100 located on the same side of the railway along the railway extension direction so that the replacement beams 200 on both sides of the railway are parallel to the railway.

[0082] Once the settlement of the replacement pile 100 is stable, i.e., the settlement rate is monitored to be ≤0.1mm / day, I-beam replacement beams 200 will be installed on the replacement piles 100 on both sides of the railway, arranged parallel to the railway.

[0083] S3: Along the extension direction of the railway, multiple connecting beams 300 are evenly distributed at the lower end of the two supporting beams 200, and the upper end of each connecting beam 300 is abutted against the bottom of the railway. The two supporting beams 200 and the multiple connecting beams 300 are connected to each other to form a support frame.

[0084] Ten I-beams 300 are evenly arranged along the railway direction at the lower end of the supporting beam 200. The upper ends of the connecting beams 300 are tightly abutted against the bottom plate of the railway bridge, forming a stable spatial support frame. It should be noted that, as... Figure 2 and Figure 3 As shown, the connecting beam 300 is set to avoid the existing pile foundation 20.

[0085] S4: A wedge adjustment device 400 is provided between the replacement pile 100 and the replacement beam 200 so that each replacement pile 100 can be in close contact with the corresponding replacement beam 200 through the wedge adjustment device 400.

[0086] It should be noted that the wedge adjustment device 400 is equipped with a drive module 420 (a lead screw servo motor), a data acquisition module (a displacement sensor, pressure sensor, vibration sensor, temperature sensor), and a control module (a PLC control system). Two wedges 410 are provided between each support pile 100 and the support beam 200, and the two wedges 410 are symmetrically arranged on the top of the support pile 100 along the front-back direction. The wedges 410 are made of high-strength alloy steel, with a slope of 1:10, and the maximum adjustment range of a single wedge 410 is 50mm.

[0087] S5: Perform phased balanced severing operations on the existing foundation structure. After each phase of severing is completed, allow it to stand for a preset time and simultaneously monitor the deformation and settlement data of the support beam 200. Adjust the wedge adjustment device 400 to compensate for the deformation and settlement deviation of the support beam 200.

[0088] This specific embodiment involves cutting off the existing pile foundation 20 in three stages:

[0089] Phase 1: Cut off one-third of the existing pile foundation section along the diameter direction and leave it to stand for 24 hours.

[0090] The first preset settlement difference value of 2mm is obtained. The four settlement acquisition units simultaneously monitor the displacement of the beam ends of the corresponding support beam 200. The acquisition module detects that the settlement of a certain support beam 200 end is 3mm different from the settlement of the ends of the other three support beams, which is greater than the first preset settlement difference value. The control module calculates the compensation amount and drives the corresponding wedge 410 to rise by 3.2mm.

[0091] Once the pressure sensor detects that the pressure has reached the target level, the locking module automatically locks the wedge 410.

[0092] Phase 2: Cut off along the diameter to two-thirds of the existing pile foundation section 20, and let it stand for 24 hours.

[0093] The preset vibration frequency of 4Hz is obtained. When the train passes by, the vibration sensor detects a characteristic frequency of 5Hz, which is greater than the preset vibration frequency. The control module fine-tunes the wedge by 0.5mm to counteract the influence of dynamic load.

[0094] Phase 3: Completely cut off the pile foundation.

[0095] The preset temperature change value of 10℃ is obtained. The temperature sensor shows that the temperature of the support beam 200 has risen by 15℃, which is greater than the preset temperature change value. The control module calculates the compensation amount of 1.8mm according to the coefficient of thermal expansion and drives the wedge 410 to adjust to the target position.

[0096] S6: After the railway load is completely transferred from the existing foundation structure to the underpass system consisting of the underpass beam 200 and the underpass pile 100, the underpass construction will be carried out.

[0097] The 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 above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for temporary pile foundation replacement construction under railways, applied to railway underpass projects, characterized in that... include: S1: Determine the scope of the existing foundation structure for replacement. Along the extension direction of the railway, symmetrically arrange replacement pile groups on both sides of the foundation structure. Each replacement pile group contains two replacement piles. The two replacement piles in the same group are arranged in a mirror image with the railway centerline as the axis. S2: After all the replacement piles have settled and stabilized, install replacement beams along the railway extension direction on two replacement piles located on the same side of the railway so that the replacement beams on both sides of the railway are parallel to the railway. S3: Along the extension direction of the railway, multiple connecting beams are evenly distributed at the lower end of the two supporting beams, and the upper end of each connecting beam abuts against the bottom of the railway. The two supporting beams and multiple connecting beams are connected to each other to form a support frame. S4: A wedge adjustment device is installed between the replacement pile and the replacement beam so that each replacement pile can be in close contact with the corresponding replacement beam through the wedge adjustment device; S5: Perform phased and balanced severing operations on the existing foundation structure. After each phase of severing is completed, allow it to stand for a preset time and monitor the deformation and settlement data of the replacement beam simultaneously. Adjust the wedge adjustment device to compensate for the deformation and settlement deviation of the replacement beam. S6: After the railway load has been completely transferred from the existing foundation structure to the underpass system consisting of underpass beams and underpass piles, the underpass construction will proceed. The wedge adjustment device includes four wedge structures. Each supporting pile and its corresponding supporting beam are connected by a wedge structure. The wedge structure is configured to adjust the elevation of the supporting beam at the millimeter level. The wedge structure includes two wedges, which are symmetrically inserted between the supporting pile and the supporting beam along the center line of the corresponding supporting beam. The wedge adjustment device also includes: The drive module is connected to the wedge and is used to drive the wedge structure to adjust the spacing between the replacement beam and the replacement pile. The locking module, the wedge and the drive module are connected to the locking module, and the locking module is used to lock the wedge that has been adjusted into place between the support beam and the support pile. The acquisition module is connected to the wedge and the drive module respectively. The acquisition module is used to monitor displacement parameters, mechanical parameters and environmental parameters in real time. The control module is connected to the drive module, locking module and acquisition module respectively. The control module is used to receive data collected by the acquisition module in order to control the actions of the drive module and locking module. In S5, adjusting the wedge adjustment device to compensate for the deformation and settlement deviation of the replacement beam includes: the acquisition module obtains the settlement value at the end of the replacement beam, the wedge contact pressure value, the ambient vibration frequency, and the replacement beam temperature value; the control module obtains the settlement difference value between each corner of the support frame based on the settlement value at the end of the replacement beam, and controls the drive module to perform a first displacement adjustment on the wedge corresponding to the maximum settlement point in the support frame based on the settlement difference value; the control module verifies the effectiveness of settlement compensation based on the wedge contact pressure value, and controls the drive module to perform a second displacement adjustment on the wedge based on the verification result; the control module obtains the characteristic frequency when the train passes based on the ambient vibration frequency, and controls the drive module to perform a third displacement adjustment on the wedge based on the characteristic frequency; the control module obtains the temperature difference between the real-time temperature of the replacement beam and the installation reference temperature based on the replacement beam temperature value, and controls the drive module to perform a fourth displacement adjustment on the wedge based on the temperature difference. The data acquisition module includes four settlement acquisition units, one of which is embedded at the end of each supporting beam. These units collect the settlement value at the corresponding end of the supporting beam. The control module controls the drive module to adjust the first displacement of the wedge corresponding to the maximum settlement point in the support frame based on the settlement difference value. This includes: acquiring the real-time settlement difference value between each corner of the support frame; when the real-time settlement difference value is greater than or equal to a first preset settlement difference value, the control module determines that the load distribution of the supporting beam is imbalanced; the control module calculates a first settlement compensation amount based on the real-time settlement difference value; and the control module controls the drive module to adjust the first displacement of the wedge corresponding to the maximum settlement point based on the first compensation amount. The wedge is adjusted until the settlement difference between the corners of the support frame is less than the first preset settlement difference value. When the real-time settlement difference value is less than the first preset settlement difference value, it is determined whether the real-time settlement value at the end of the supporting beam is greater than the second preset settlement difference value. When the real-time settlement value at the end of the supporting beam is greater than the second preset settlement difference value, the control module calculates the second compensation amount based on the real-time settlement value at the end of the supporting beam, and the control module controls the drive module to perform wedge adjustment according to the second settlement compensation amount on the wedge at the end of the supporting beam. Otherwise, the control module determines that the load distribution of the supporting beam is reasonable, and the control module controls the locking module to perform locking on the wedge. The acquisition module also includes eight contact pressure acquisition units. Each wedge has a corresponding contact pressure acquisition unit on its contact surface. The contact pressure acquisition unit is used to acquire the contact pressure of the corresponding wedge. The control module controls the drive module to perform a second displacement adjustment on the wedge based on the verification results, including: acquiring the real-time contact pressure of the wedge; when the real-time contact pressure of the wedge is less than the first preset contact pressure value, the control module determines that the contact between the wedge and the support beam has failed, and the control module controls the drive module to continue to perform the wedge adjustment process until the settlement value of the support beam reaches the first preset contact pressure value; otherwise, the control module determines that the contact between the wedge and the support beam has been successful, and the control module controls the locking module to perform a locking process on the wedge. The acquisition module also includes two environmental vibration acquisition units. Each supporting beam has an environmental vibration acquisition unit at its lower edge. The environmental vibration acquisition unit is used to acquire the characteristic frequency of the train passing by. The control module controls the drive module to perform a third displacement adjustment on the wedge according to the characteristic frequency, including: acquiring the real-time environmental vibration frequency; confirming whether the wedge meets the vibration release condition based on the environmental vibration frequency; when the environmental vibration frequency is greater than the preset vibration frequency, the control module determines that the wedge meets the vibration release condition, the control module generates a dynamic load compensation amount based on the environmental vibration frequency, and the control module controls the drive module to perform wedge adjustment processing according to the dynamic load compensation amount until the real-time contact pressure of the wedge meets the second preset contact pressure value; otherwise, it is determined that the wedge does not meet the vibration release condition, and the control module controls the locking module to perform locking processing on the wedge. The acquisition module also includes two temperature acquisition units. Each support beam has a temperature acquisition unit on its upper edge. The temperature acquisition unit is used to acquire the surface temperature of the support beam. The control module controls the drive module to perform a fourth displacement adjustment on the wedge based on the temperature difference. This includes: acquiring the real-time temperature of the support beam and the installation reference temperature; acquiring the temperature change value of the support beam based on the real-time temperature and the installation reference temperature; when the temperature change value is greater than the preset temperature change value, the control module determines that the support beam has a displacement error, acquires the linear expansion coefficient and the original length of the support beam, and acquires the thermal deformation compensation amount based on the linear expansion coefficient, the original length of the support beam, and the temperature change value of the support beam. The control module controls the drive module to perform wedge adjustment processing based on the thermal deformation compensation amount. Otherwise, it is determined that the support beam has not generated a displacement error, and the control module controls the locking module to perform locking processing on the wedge.

2. The method for temporary pile foundation replacement construction under railways according to claim 1, characterized in that, In S1, two steel plate supports are provided between each replacement pile and the corresponding replacement beam. One steel plate support is located at the top of the replacement pile, and the other steel plate support is located at the bottom of the corresponding replacement beam. The wedge adjustment device is connected to the two steel plate supports respectively. The steel plate supports are configured to cooperate with the wedge adjustment device to adjust the distance between the replacement beam and the replacement pile.

3. The method for temporary pile foundation replacement construction under railways according to claim 1, characterized in that, In S1, the replacement pile group is spaced 30m to 50m apart from the existing foundation structure.

4. The method for temporary pile foundation replacement construction under railways according to claim 1, characterized in that, The drive module includes eight drive units, one for each wedge, and a corresponding vibration auxiliary unit for each drive unit. The vibration auxiliary unit is configured to disrupt the static friction of the wedge contact surface to ensure smooth advance and retraction of the wedge. The wedge adjustment process includes: Obtain the real-time operating current of the drive unit, and determine whether the wedge is difficult to drive based on the real-time operating current. When the calculated driving resistance is greater than the preset resistance threshold, the control module determines that the friction resistance suppression step condition is met, and the control module controls the corresponding auxiliary unit to vibrate to assist the wedge propulsion. Conversely, if the condition for the friction resistance suppression step is not met, the control module generates an auxiliary sleep signal and adjusts the auxiliary unit to sleep mode based on the auxiliary sleep signal.

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