Construction method for scour repair of group pile foundation of cross-sea bridge by using solidified soil

Abstract

The application provides a construction method for repairing scouring of group pile foundations of cross-sea bridges by using solidified soil, mud is subjected to flow solidification treatment to produce high-water-content flow-state solidified soil, the early flowability of the high-water-content flow-state solidified soil is utilized to pump the high-water-content flow-state solidified soil into scouring pits around the group pile foundations of the cross-sea bridges, and the high-water-content flow-state solidified soil is gradually solidified to form a filling structure, so that the scouring pits are repaired and scouring protection is achieved. The construction method for repairing scouring of group pile foundations of cross-sea bridges by using solidified soil can treat mud of various sources, realize resource utilization, and reduce mud disposal cost; the whole process of mud pumping construction can be simulated to provide a reference for optimization of a construction scheme; the method is more efficient and controllable, can significantly reduce engineering construction cost, and improves construction quality.

Description

Technical Field

[0001] This invention relates to the field of civil engineering, and in particular to a construction method for scour repair of pile foundations of cross-sea bridges using solidified soil. Background Technology

[0002] The pile foundations of cross-sea bridges are located in a complex near-shore marine environment, making them susceptible to localized scour and affecting structural stability. Therefore, scour protection and repair of the foundations are necessary. As a promising scour protection technology, solidified soil scour protection technology utilizes the fluidity of high-moisture-content, liquid solidified soil. This liquid solidified soil is pumped into scour pits around the foundation, where it solidifies and hardens to form a protective structure.

[0003] Currently, the technology of solidified soil for erosion control is in its early stages, and there is no experience to draw upon in its application to the erosion repair of pile foundations in cross-sea bridges. Furthermore, the environment around pile foundations is often more complex and variable, and under the influence of wave currents, the fluidized solidified soil is easily lost, leading to material waste, deterioration of construction quality, and increased uncertainty and uncertainty in the construction process.

[0004] Therefore, it is of great significance to propose a construction method for scouring and repairing the pile foundation of a cross-sea bridge using fluidized solidified soil. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a construction method for scour repair of pile foundations of cross-sea bridges using solidified soil. This method can perform flow solidification treatment on mud from various sources and can be applied to the scour protection and repair of pile foundations of cross-sea bridges, enabling large-scale disposal of mud and realizing the resource utilization of mud from various sources.

[0006] To achieve the above objectives, this invention provides a construction method for scour repair of pile foundations of cross-sea bridges using solidified soil, comprising the following steps:

[0007] S1: A multibeam echo sounder system was used to conduct an on-site survey of the pile foundation of a cross-sea bridge to obtain topographic data of the scour pits around the pile foundation.

[0008] S2: The wave flow environment parameters and physical parameters of the fluidized solidified soil at the construction site were measured through field tests and indoor tests.

[0009] S3: Import the topographic data of the scour pit, the wave-current environment parameters, and the physical parameters of the fluidized solidified soil into a computational fluid dynamics numerical software, establish a full-scale multiphase flow numerical model of the scour pit for a pile foundation in a wave-current marine environment, and obtain numerical simulation results; the numerical simulation results include: simulating the flow and diffusion process of high water content fluidized solidified soil in a wave-current marine environment, and calculating the retention rate and morphology of solidified soil in the scour pit after the simulation.

[0010] S4: Based on the actual construction site of the batch pumping grouting, and based on the numerical simulation results, evaluate the pumping grouting effect, optimize the pumping grouting points around the pile foundation, preliminarily calculate the engineering quantity of the high water content fluidized solidified soil, and determine the pumping grouting construction plan.

[0011] S5: Prepare mud with a specified moisture content, transport it to the construction site in batches by transport ship, pump the mud with the specified moisture content onto the construction ship, add a quantitative amount of solidifying agent to the mud with the specified moisture content on the construction ship, stir evenly, and prepare the high moisture content fluid solidified soil.

[0012] S6: According to the slurry pumping construction plan, the slurry pumping pipe is positioned using an anchor boat, and the mud pump is turned on to pump the high water content fluidized solidified soil.

[0013] S7: After the pumping construction is completed, the multibeam echo sounding system is used to conduct a sweep around the pile foundation in a timely manner to ensure that the high water content fluid solidified soil in the scour pit reaches the control elevation and does not flow out in large quantities. After the construction is completed, the results are swept regularly to verify the effectiveness of the scour protection of the solidified soil structure.

[0014] Preferably, in step S3:

[0015] In the full-scale numerical model of multiphase flow, the high water content fluidized solidified soil is regarded as a non-Newtonian fluid with viscosity, and a rheological model is used to describe the properties of the high water content fluidized solidified soil. The water in the wave-current marine environment is regarded as a Newtonian fluid. The rheological model parameters are obtained by conducting rheological tests on the high water content fluidized solidified soil at the construction site and then imported into the full-scale numerical model of multiphase flow. The pile foundation, the grouting pipe and the seabed in the full-scale numerical model of multiphase flow are all regarded as non-deformable rigid bodies.

[0016] Preferably, in step S3:

[0017] The retention rate R of the solidified soil was calculated using the mass method:

[0018] R = m2 / m1 (1);

[0019] Wherein, m1 is the mass of the high water content fluidized solidified soil pumped out from the pump slurry inlet, and m2 is the mass of the high water content fluidized solidified soil remaining in the scour pit after the simulation is completed.

[0020] Preferably, in step S5:

[0021] The mud source for the specified moisture content mud includes: engineering waste mud, dredged silt, and marine tidal flats; the organic matter content of the mud source is less than 5% by mass.

[0022] The curing agent includes: cement, inorganic composite curing agent, organic curing agent and ionic curing agent; geotechnical parameters and mineral composition are analyzed for the mud with the specified moisture content, and based on the obtained data and the requirements of the actual project for the strength and fluidity of the cured soil, the corresponding curing agent is formulated and the dosage of the curing agent is determined;

[0023] The high-moisture-content fluidized solidified soil uses an acrylic cylinder with an inner diameter and height of 8cm. The flow value of the acrylic cylinder measured on the acrylic plate is in the range of 16cm-20cm, which meets the requirements for pumping construction. The unconfined compressive strength of the high-moisture-content fluidized solidified soil after natural curing for 28 days is greater than 400kPa, which meets the strength requirements.

[0024] Because the present invention adopts the above technical solution, it has the following beneficial effects:

[0025] This invention relates to a design and construction method for scour repair of pile foundations of cross-sea bridges using fluidized solidified soil.

[0026] (1) This invention can perform flow solidification treatment on mud from various sources and apply it to the scour protection and repair of pile foundations of cross-sea bridges, dispose of mud on a large scale, and realize the resource utilization of mud from various sources.

[0027] (2) This invention uses computational fluid dynamics numerical software and applies a full-scale numerical model of multiphase flow to simulate the pumping process. It can intuitively and quantitatively evaluate the effect of solidified soil pumping, provide a theoretical basis for the selection of pumping points, and help optimize the pumping construction plan.

[0028] (3) Based on multi-beam scanning technology, the terrain around the pile foundation is scanned to obtain accurate pre-construction and post-construction terrain conditions, which can provide full-cycle guidance for the protection and repair of solidified soil erosion. In addition, numerical modeling is performed based on the terrain data obtained from the scanning, making the model closer to reality and the results more referential.

[0029] (4) For the application scenarios of scour protection and repair of pile foundations in marine environment, an adaptive pumping construction method is proposed. The method is more efficient and controllable, which can significantly reduce the engineering construction cost and improve the construction quality. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a full-scale numerical model of multiphase flow according to an embodiment of the present invention. Detailed Implementation

[0031] The following is based on the attached diagram. Figure 1 The present invention provides preferred embodiments and describes them in detail to enable a better understanding of the functions and features of the present invention.

[0032] Please see Figure 1 This invention discloses a construction method for scour repair of cross-sea bridge pile foundations using solidified soil, comprising the following steps:

[0033] S1: A multibeam echo sounding system was used to conduct an on-site survey of the pile foundation 2 of a cross-sea bridge to obtain topographic data of the scour pits around the pile foundation 2.

[0034] S2: The wave flow environment parameters and physical parameters of the fluidized solidified soil at the construction site were measured through field tests and indoor tests.

[0035] S3: Import the topographic data of the scour pit, wave-current environment parameters, and physical parameters of the fluidized solidified soil into the computational fluid dynamics numerical software Fluent, establish a full-scale multiphase flow numerical model of the scour pit of the pile foundation 2 in the wave-current marine environment 5, and obtain the numerical simulation results; the numerical simulation results include: the simulation of the flow and diffusion process of the high water content fluidized solidified soil 3 in the wave-current marine environment 5, and the calculation of the solidified soil retention rate and morphology in the scour pit after the simulation.

[0036] In the full-scale numerical model of multiphase flow, the high water content fluidized solidified soil 3 is regarded as a viscous non-Newtonian fluid, and the properties of the high water content fluidized solidified soil 3 are described by a rheological model. The water in the wave-current marine environment 5 is regarded as a Newtonian fluid. The rheological model parameters are obtained by conducting rheological tests on the high water content fluidized solidified soil 3 at the construction site and then imported into the full-scale numerical model of multiphase flow. The pile foundation 2, the grouting pipe 1, and the seabed 4 in the full-scale numerical model of multiphase flow are all regarded as non-deformable rigid bodies.

[0037] Based on the statistical data of wave and current environment parameters near the Donghai Bridge, the water depth in the numerical model is determined to be 10m, the tidal current velocity is 1m / s, the average wave height is 2.83m, and the average wave period is 7.76s.

[0038] Considering the effects of pumping velocity and pumping point location, the retention rate and morphology of solidified soil in the scour pit after the simulation were obtained. The solidified soil retention rate R was calculated using the mass method.

[0039] R = m2 / m1 (1);

[0040] Where m1 is the mass of the high-moisture-content fluidized solidified soil 3 pumped out from pump pipe 1, and m2 is the mass of the high-moisture-content fluidized solidified soil 3 remaining in the scour pit after the simulation is completed.

[0041] S4: Based on the actual construction site of batch pumping grouting, and based on the numerical simulation results, the effect of pumping grouting is evaluated according to the retention rate and integrity of the solidified soil in the flushing pit after pumping grouting. The pumping points around the pile foundation 2 are optimized, the engineering quantity of high water content fluid solidified soil 3 is preliminarily calculated, and the pumping grouting construction plan is determined.

[0042] S5: Prepare mud with a specified moisture content, transport it to the construction site in batches by transport ship, pump the mud with the specified moisture content onto the construction ship, add a quantitative amount of curing agent to the mud with the specified moisture content on the construction ship, stir evenly, and prepare high moisture content fluid solidified soil 3.

[0043] The mud sources for mud with specified moisture content include: engineering waste mud, dredged silt and marine tidal flats; the organic matter content of the mud source is less than 5% by mass.

[0044] The curing agents include: cement, inorganic composite curing agents, organic curing agents, and ionic curing agents; geotechnical parameters and mineral composition analysis are performed on mud with a specified moisture content, and based on the obtained data and the actual engineering requirements for the strength and fluidity of the cured soil, the corresponding curing agent is formulated and the dosage of the curing agent is determined;

[0045] The high moisture content fluidized solidified soil 3 uses an acrylic cylinder with an inner diameter and height of 8cm. The flow value measured on the acrylic plate of the acrylic cylinder is 16cm-20cm, which meets the requirements for pumping construction. The unconfined compressive strength of the high moisture content fluidized solidified soil 3 after natural curing for 28 days is greater than 400kPa, which meets the strength requirements.

[0046] In this embodiment, the mud source for the specified water content mud is high water content mud made from waste soil from a certain project; the mud is transported to the construction site by a transport ship and pumped onto the construction ship, where a quantitative amount of prepared inorganic composite curing agent is added and stirred evenly to produce high water content fluid solidified soil 3; the high water content fluid solidified soil 3 uses an 8cm inner diameter and height organic glass cylinder and the flow value measured on the organic glass plate is 16cm-20cm, which meets the requirements for pumping construction; the unconfined compressive strength of the solidified soil after natural curing for 28 days is greater than 500kPa, which meets the strength requirements;

[0047] S6: According to the grouting construction plan, the grouting pipe 1 is positioned by the anchor boat, and the mud pump is turned on to pump the high water content fluid solidified soil 3.

[0048] S7: After the pumping construction is completed, a multibeam echo sounding system is used to conduct a sweep around the pile foundation 2 in a timely manner to ensure that the high water content fluid solidified soil 3 in the scour pit reaches the control elevation and does not flow out in large quantities. Five results sweeps are conducted in the 1st, 2nd, 3rd, 6th and 12th months after the construction is completed to verify the effectiveness of the scour protection of the solidified soil structure.

[0049] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A construction method for scour repair of pile foundations of a cross-sea bridge using solidified soil, comprising the following steps: S1: A multibeam echo sounder system was used to conduct an on-site survey of the pile foundation of a cross-sea bridge to obtain topographic data of the scour pits around the pile foundation. S2: Through field tests, the wave flow environment parameters and physical parameters of the fluidized solidified soil at the construction site were measured; S3: Indoor Test: Import the topographic data of the scour pit, the wave-current environment parameters, and the physical parameters of the fluidized solidified soil into a computational fluid dynamics numerical software to establish a full-scale multiphase flow numerical model of the scour pit for a pile group foundation in a wave-current marine environment, and obtain numerical simulation results; the numerical simulation results include: The flow and diffusion process of high-moisture-content fluidized solidified soil in a wave-current marine environment was simulated, and the retention rate and morphology of solidified soil in the scour pit after the simulation were calculated. S4: Based on the actual construction site of the batch pumping grouting, and based on the numerical simulation results, the effect of the pumping grouting is evaluated according to the retention rate and integrity of the solidified soil in the flushing pit after the pumping is completed. The pumping points around the pile foundation are optimized, the engineering quantity of the high water content fluid solidified soil is preliminarily calculated, and the pumping grouting construction plan is determined. S5: Prepare mud with a specified moisture content, transport it to the construction site in batches by transport ship, pump the mud with the specified moisture content onto the construction ship, add a quantitative amount of solidifying agent to the mud with the specified moisture content on the construction ship, stir evenly, and prepare the high moisture content fluid solidified soil. S6: According to the slurry pumping construction plan, the slurry pumping pipe is positioned using an anchor boat, and the mud pump is turned on to pump the high water content fluidized solidified soil. S7: After the pumping construction is completed, the multibeam echo sounding system is used to conduct a sweep around the pile foundation in a timely manner to ensure that the high water content fluid solidified soil in the scour pit will not flow out in large quantities when it reaches the predetermined elevation. After the construction is completed, the solidified soil structure is regularly inspected to verify the effectiveness of the solidified soil structure in protecting against scour.

2. The construction method for scour repair of cross-sea bridge pile foundations using solidified soil according to claim 1, characterized in that, In step S3: In the full-scale numerical model of multiphase flow, the high water content fluidized solidified soil is regarded as a non-Newtonian fluid with viscosity, and a rheological model is used to describe the properties of the high water content fluidized solidified soil. The water in the wave-current marine environment is regarded as a Newtonian fluid. The rheological model parameters are obtained by conducting rheological tests on the high water content fluidized solidified soil at the construction site and then imported into the full-scale numerical model of multiphase flow. The pile foundation, the grouting pipe and the seabed in the full-scale numerical model of multiphase flow are all regarded as non-deformable rigid bodies.

3. The construction method for scour repair of cross-sea bridge pile foundations using solidified soil as described in claim 1, characterized in that, In step S3: The retention rate R of the solidified soil was calculated using the mass method: R=m2 / m1 (1) Wherein, m1 is the mass of the high water content fluidized solidified soil pumped out from the pump slurry inlet, and m2 is the mass of the high water content fluidized solidified soil remaining in the scour pit after the simulation is completed.

4. The construction method for scour repair of cross-sea bridge pile foundations using solidified soil according to claim 1, characterized in that, In step S5: The mud source for the specified moisture content mud includes: engineering waste mud, dredged silt, and marine tidal flats; the organic matter content of the mud source is less than 5% by mass. The curing agent includes: cement, inorganic composite curing agent, organic curing agent and ionic curing agent; geotechnical parameters and mineral composition analysis are performed on the mud with the specified moisture content, and based on the obtained data and the actual engineering requirements for the strength and fluidity of the cured soil, the corresponding curing agent is formulated and the dosage of the curing agent is determined; The high-moisture-content fluidized solidified soil uses an acrylic cylinder with an inner diameter and height of 8cm. The flow value of the acrylic cylinder measured on the acrylic plate is in the range of 16cm-20cm, which meets the requirements for pumping construction. The unconfined compressive strength of the high-moisture-content fluidized solidified soil after natural curing for 28 days is greater than 400kPa, which meets the strength requirements.

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