Water conservancy project pump station elbow-shaped runner formwork supporting and reinforcing construction method

Abstract

The invention provides a water conservancy project pump station elbow-shaped flow channel formwork supporting and reinforcing construction method, and belongs to the technical field of building construction.The method includes the steps that firstly, a three-dimensional model is established through building information model software, and a steel bar keel arrangement and flow state soil solidification scheme is determined; then measuring and setting out on site, and determining the optimal arrangement of the steel bar keel by using a minimum supporting point covering algorithm; calculating surface parameters by adopting a curved surface fitting equation, and cutting and splicing the bamboo plywood on the surface of the steel bar keel; laying a flexible template and attaching a galvanized iron sheet for fixing; preparing flow-state solidified soil with the strength of 0.8-1.2 MPa according to the environment temperature and a flow-state solidified soil rheological equation; pouring and filling layer by layer according to the calculated minimum thickness; checking the stability of the template after curing; after concrete pouring is completed and the design strength is reached, the fluid solidified soil is removed, and the formwork is removed; and finally checking the surface quality of the elbow-shaped runner to ensure that design requirements are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of building construction, and in particular relates to a support and reinforcement construction method for an elbow-type flow channel template of a water conservancy project pump station. Background Art

[0002] Pump stations are a vital component of urban drainage systems. Elbow channels, the curved structures connecting the pump inlet and outlet pipes, have a crucial impact on pump station efficiency. Traditional elbow channel construction utilizes wooden or steel formwork support systems, secured with wooden wedges, steel pipe supports, and embedded bolts to form the concrete. These support systems require extensive on-site assembly and adjustment, requiring high-level technical expertise.

[0003] However, traditional support methods have obvious shortcomings when dealing with complex curved structures: first, ordinary wooden and steel formwork systems have limited strength in withstanding the lateral pressure generated during concrete pouring; second, traditional support structures have difficulty forming an effective force-bearing system in the complex curved space of elbow-shaped flow channels, resulting in an unreasonable distribution of support points; third, conventional supports are difficult to arrange in areas with large curvatures and narrow spaces, resulting in insufficient support in some areas.

[0004] Crucially, as the concrete pour height increases, the lateral pressure on the bottom formwork significantly increases, exacerbating the problem of insufficient strength in conventional support systems. This can easily lead to formwork deformation or displacement, affecting the geometry and surface flatness of the elbow channel, ultimately reducing the channel's hydraulic performance and the pump station's operating efficiency. In other words, the existing technology suffers from insufficient support strength for the complex curved formwork of the pump station's elbow channel. Summary of the Invention

[0005] In view of this, the present invention provides a support and reinforcement construction method for the elbow-shaped flow channel template of a water conservancy project pump station, which can solve the technical problem of insufficient support strength of the complex curved surface template of the elbow-shaped flow channel of the pump station in the prior art.

[0006] The present invention is implemented as follows: The present invention provides a method for supporting and reinforcing the formwork of an elbow-shaped flow channel in a water conservancy project pump station, including: using building information modeling software to establish a three-dimensional model of the elbow-shaped flow channel, determining the layout of the steel keel and the filling scheme of fluidized solidified soil; measuring and laying out on site, and using the minimum support point coverage algorithm to determine the optimal layout position of the steel keel; calculating the surface parameters of the elbow-shaped flow channel through a surface fitting equation, and cutting and assembling bamboo plywood on the surface of the steel keel; laying and fixing a flexible formwork; preparing fluidized solidified soil; injecting the fluidized solidified soil into the formwork and pouring it in layers; checking the formwork surface after the fluidized solidified soil is solidified, and confirming that the stability and strength of the formwork meet the requirements for concrete pouring; after the concrete pouring is completed and reaches the design strength, removing the fluidized solidified soil and removing the formwork; checking the surface quality of the elbow-shaped flow channel to ensure that it meets the design requirements.

[0007] Among them, the building information modeling software is used to establish a three-dimensional model of the elbow-shaped flow channel, including determining the spatial layout of the steel keel and the flow-solidified soil filling plan, generating construction drawings and material lists, clarifying the template size and steel bar specifications, and calculating the design flow rate, flow channel turning angle, inlet diameter, outlet diameter and flow channel axis curvature radius.

[0008] Among them, on-site measurement and layout include marking the outline of the elbow flow channel and key control points, discretizing the surface of the elbow flow channel into a node network, using the minimum support point coverage algorithm to determine the optimal layout position of the steel keel, and adding reinforcement ribs at the turning points of the curved surface to maximize the structural support strength and minimize the use of steel bars.

[0009] The surface parameters of the elbow-shaped flow channel are calculated by the surface fitting equation. The bamboo plywood is cut into the required size according to the surface parameters, assembled and attached to the surface of the steel keel according to the layout drawing, and fixed with cement nails or iron wire to ensure that the joints are tight and the surface is flat.

[0010] Among them, laying the flexible formwork includes laying the flexible formwork on the outside of the bamboo plywood, and fitting the galvanized iron sheet, fixing it with straps or clamps to ensure that the flexible formwork fits tightly to the surface of the bamboo plywood to prevent displacement during the pouring process, and measuring the formwork span value before pouring the fluidized solidified soil.

[0011] Among them, the preparation of fluidized solidified soil includes measuring the ambient temperature, determining the dosage of admixtures, calculating the water-cement ratio, predicting the flow properties and setting time through the rheological equation of fluidized solidified soil, preparing the fluidized solidified soil according to the design requirements, and ensuring that the strength after solidification is between 0.8 and 1.2 MPa.

[0012] Among them, injecting the fluidized solidified soil into the formwork includes calculating the minimum filling thickness of the fluidized solidified soil according to the support bearing equation, using pumping equipment to inject the fluidized solidified soil into the formwork, pouring it in layers from low to high, and controlling the thickness of each layer at 30 to 50 cm. Use a vibrating rod to gently vibrate to ensure sufficient filling and monitor the pouring rate.

[0013] Among them, checking the formwork surface after the fluidized solidified soil solidifies includes calculating the solidification time using the rheological equation of the fluidized solidified soil. After the fluidized solidified soil solidifies, checking whether the formwork surface is damaged, performing necessary repairs, measuring the actual strength of the fluidized solidified soil, and confirming that the stability and strength of the formwork meet the requirements for concrete pouring.

[0014] Among them, after the concrete pouring is completed and reaches the design strength, it includes calculating the concrete pouring height and density, determining the safety factor, and verifying that the filling thickness of the fluidized solidified soil meets the bearing requirements based on the support bearing equation. After the concrete pouring is completed and reaches the design strength, use an electric pick to remove the fluidized solidified soil, remove the formwork, and check the surface quality of the elbow flow channel.

[0015] Among them, the minimum support point coverage algorithm is used to determine the minimum number of steel keel layout points that meet the support strength requirements, reducing material consumption and improving construction efficiency; the support bearing equation is a mathematical expression for calculating the minimum thickness required for the fluidized solidified soil fill layer to ensure that it can withstand the lateral pressure generated by concrete pouring without deformation or damage.

[0016] Compared with the existing technology, the present invention provides a method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station. The present invention proposes a method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station, which combines building information modeling technology, minimum support point coverage algorithm and fluidized solidified soil filling support technology to achieve high-strength support for complex curved surface formwork.

[0017] This method establishes an accurate three-dimensional model, uses surface fitting equations and minimum support point coverage algorithms to determine the optimal steel keel layout, adds reinforcement bars at the turning points of the surface, and forms a reasonable force system. It combines bamboo plywood with flexible formwork to improve the overall stiffness of the formwork. It innovatively introduces fluidized solidified soil as a filling support material. Its good flowability enables it to completely fill the gap between the formwork and the external support, forming a uniform and continuous support layer, providing sufficient support strength to resist the lateral pressure of concrete.

[0018] Compared to conventional technologies, the method presented in this paper significantly improves the support strength of the elbow-shaped channel formwork. Even when the concrete pouring height increases and lateral pressure builds up, the formwork remains stable and does not deform. This ensures the geometric accuracy and surface quality of the elbow-shaped channel after formation, guaranteeing the channel's hydraulic performance and the pump station's operating efficiency, fundamentally resolving the technical issue of insufficient support strength for complex curved formwork. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present invention;

[0020] Figure 2 Schematic diagram of the elbow flow channel of the present invention

[0021] Figure 3 This is a cross-sectional view of the inlet section of the elbow-type flow channel of the present invention;

[0022] Figure 4 This is a cross-sectional view of the outlet section of the elbow-type flow channel of the present invention;

[0023] Figure 5 This is a cross-sectional view of the elbow-shaped flow channel bending section of the present invention;

[0024] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0025] 1. Elbow flow channel; 11. Inlet section; 12. Outlet section; 13. Bend section. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] like Figure 1-Figure 5 FIG. 1 is a flow chart of a method for supporting and reinforcing a formwork for an elbow-shaped flow channel in a water conservancy project pump station provided by the present invention. The method comprises the following steps:

[0028] S01. Use building information modeling software to create a three-dimensional model of the elbow flow channel, determine the spatial layout of the steel keel and the fluidized solidified soil filling plan, generate construction drawings and a bill of materials, specify the template dimensions and steel bar specifications, and calculate the design flow rate, flow channel angle, inlet diameter, outlet diameter, and flow channel axis curvature radius;

[0029] S02. Based on the building information model and construction drawings, survey and lay out the elbow channel outline and key control points on site. Discretize the elbow channel 1 surface into a node network. Use the minimum support point coverage algorithm to determine the optimal placement of the steel keel. Add reinforcement bars at the turning points of the curved surface to maximize the structural support strength and minimize the amount of steel bars used.

[0030] S03. Calculate the surface parameters of the elbow-shaped flow channel using the surface fitting equation. Cut the bamboo plywood into the required size based on the surface parameters. Assemble and attach it to the steel keel surface according to the layout diagram. Secure with cement nails or wire to ensure that the joints are tight and the surface is flat.

[0031] S04. Lay flexible formwork on the outside of the bamboo plywood and attach galvanized iron sheets. Secure with straps or clamps to ensure the flexible formwork fits tightly against the surface of the bamboo plywood to prevent displacement during pouring. Measure the formwork span value before pouring with fluidized solidified soil.

[0032] S05. Measure the ambient temperature, determine the admixture dosage, calculate the water-cement ratio, predict the flow properties and setting time using the rheological equation of fluidized solidified soil, prepare the fluidized solidified soil according to the design requirements, and ensure the strength after solidification is between 0.8 and 1.2 MPa;

[0033] S06. Calculate the minimum thickness of the fluidized solidified soil fill based on the support bearing equation. Use pumping equipment to inject the fluidized solidified soil into the formwork, pouring it layer by layer from low to high. Keep each layer 30-50 cm thick. Use a vibrator to gently vibrate to ensure sufficient filling, and monitor the pouring rate.

[0034] S07. Calculate the setting time using the rheological equation for fluidized solidified soil. After the fluidized solidified soil solidifies, check whether the formwork surface is damaged and perform necessary repairs. Measure the actual strength of the fluidized solidified soil to confirm that the formwork stability and strength meet the requirements for concrete pouring.

[0035] S08. Calculate the concrete pouring height and density, determine the safety factor, and verify that the fluidized solidified soil filling thickness meets the load-bearing requirements based on the support load equation. After the concrete pouring is completed and reaches the design strength, use an electric pick to remove the fluidized solidified soil, remove the formwork, and inspect the surface quality of the elbow runner.

[0036] S09. Organize construction records and quality inspection reports, check the size, surface flatness and strength of the elbow flow channel to ensure that they meet the design requirements, submit them to the supervision unit for acceptance, evaluate the deviation between the surface parameters of the elbow flow channel and the design values, and confirm that the hydraulic performance meets the design requirements.

[0037] Building Information Modeling software refers to a software tool used to create accurate three-dimensional models of elbow-shaped flow channels, enabling construction plan optimization and accurate calculation of material usage;

[0038] Among them, the elbow flow channel refers to the curved pipe structure connecting the water pump inlet and outlet pipes in the pump station. The smoothness of the internal water flow has a significant impact on the operating efficiency of the pump station.

[0039] Among them, the steel keel refers to the steel skeleton structure used to support the formwork, which is arranged in spatial position according to the building information model to provide overall rigidity and stability;

[0040] Among them, flexible formwork refers to plastic formwork materials that can adapt to complex curved surfaces and can fit tightly to irregular surfaces;

[0041] Among them, fluidized solidified soil refers to a filling material with good fluidity and moderate strength after solidification. Compared with traditional supports, it is easier to fill small spaces and is convenient for later removal;

[0042] The design flow rate refers to the water flow rate that the elbow channel needs to carry, in cubic meters per second, and is determined through hydraulic calculations;

[0043] The channel angle refers to the angle between the inlet axis and the outlet axis of the elbow channel, measured in degrees and determined by the design drawings.

[0044] The inlet diameter refers to the diameter of the cross section of the elbow flow channel inlet, in meters, and is determined by the design drawings;

[0045] The outlet diameter refers to the diameter of the cross section of the elbow flow channel outlet, in meters, and is determined by the design drawings;

[0046] The curvature radius of the flow channel axis refers to the curvature radius of the center line of the elbow flow channel, in meters, and is determined by the design drawing;

[0047] The surface fitting equation is a mathematical expression used to determine the layout of the steel keel and the cutting size of the bamboo plywood, ensuring that the final elbow-shaped flow channel conforms to the optimal hydraulic streamline structure. The input includes the design flow rate, flow channel angle, inlet diameter, outlet diameter, and the curvature radius of the flow channel axis. The output is the surface parameters in three-dimensional space, which are used to guide the layout of the steel keel and the cutting of the bamboo plywood.

[0048] The minimum support point coverage algorithm is a graph-based optimization algorithm used to determine the minimum number of steel bar layout points that meet support strength requirements, thereby reducing material usage and improving construction efficiency.

[0049] The template span refers to the distance between adjacent support points, measured in meters and obtained through on-site measurement;

[0050] Among them, the water-cement ratio refers to the mass ratio of water to cementitious materials in fluidized solidified soil, which is determined by mix design;

[0051] Among them, the admixture dosage refers to the mass percentage of the admixture in the fluidized solidified soil, which is determined by the mix design;

[0052] Among them, the ambient temperature refers to the temperature at the construction site, in degrees Celsius, measured by a temperature measuring instrument;

[0053] The rheological equation for fluidized solidified soil is a mathematical expression used to predict the flow properties and setting time of fluidized solidified soil during the pouring process, ensuring that the filler completely fills the formwork and provides sufficient support strength. Inputs include water-cement ratio, ambient temperature, admixture dosage, setting time, and shear stress; outputs are the apparent viscosity and setting strength of the fluidized solidified soil.

[0054] The pouring rate refers to the thickness of concrete poured per unit time, measured in meters per hour, and is obtained from construction records.

[0055] Among them, the safety factor refers to the coefficient that takes uncertainty factors into account in structural design and is determined by design specifications;

[0056] The support bearing equation is a mathematical expression for calculating the minimum thickness of the fluidized soil fill layer to ensure that it can withstand the lateral pressure generated by concrete pouring without deformation or damage. The input includes the concrete pouring height, concrete density, pouring rate, fluidized soil strength, and safety factor. The output is the minimum thickness of the fluidized soil fill.

[0057] The specific implementation methods of the above steps are described in detail below. The specific implementation method of step S01 is to construct a three-dimensional model of the elbow flow channel using building information modeling software. First, basic parameters such as the design flow rate, flow channel angle, inlet diameter, outlet diameter, and flow channel axis curvature radius are input. The flow characteristics of the fluid in the elbow flow channel are determined using the principles of computational fluid dynamics. The geometric shape of the elbow flow channel is determined using the optimal streamline method, thereby reducing head loss and vortex generation. The layout plan of the steel keel is determined using a spatial support structure optimization algorithm. This algorithm is based on the principles of structural mechanics and uses iterative calculations to find the optimal steel arrangement plan that meets the strength requirements. At the same time, the structural strength and stability of the model are verified using the finite element analysis method, and local reinforcement design is performed for stress concentration areas. After determining the elbow flow channel model and the steel keel layout, a template segmentation plan is generated using three-dimensional solid slicing technology, the cutting size and angle of each template are calculated, and detailed construction drawings and a bill of materials are generated. The purpose of this step is to provide an accurate technical basis for subsequent construction through accurate three-dimensional model design, ensuring that the hydraulic and structural performance of the elbow flow channel meet the design requirements.

[0058] The specific implementation of step S02 involves optimizing the layout of the steel keels based on on-site surveying and setting out. First, a total station or theodolite is used to accurately survey the site. The spatial location of the elbow channel is determined based on the building information model. The elbow channel's outline and key control points are marked, with control points spaced no more than 0.5 meters apart. A discretization method is then used to segment the elbow channel surface into a triangular mesh with a mesh size of 10 to 20 centimeters. A node network is constructed as the basis for the layout of the steel keels. Next, a minimum support point cover algorithm is applied to determine the optimal placement of the steel keels. This algorithm, based on the dominating set theory in graph theory, constructs an adjacency graph of surface nodes and solves for the minimum dominating set that satisfies the cover constraint, achieving a balance between maximizing structural support strength and minimizing steel usage. Based on the algorithm's calculation results, reinforcing bars are added at curved corners and stress concentration areas, with the spacing between the bars being 50% to 70% of the standard spacing to ensure that the formwork does not deform or fail due to excessive local stress during concrete pouring. This step optimizes the steel keel layout through a scientific algorithm, ensuring structural strength while reducing material usage and improving construction efficiency.

[0059] The specific implementation method of step S03 is to produce and install the template based on the surface fitting equation. First, based on the discretized surface node coordinates, a mathematical model of the elbow flow channel surface is constructed using the B-spline surface fitting method to obtain the surface parameter equation. Then, a numerically controlled cutting device is used to cut the bamboo plywood into the required size and shape according to the fitted surface parameters, with the cutting accuracy controlled within ±2 mm. For complex curved surface areas, the bamboo plywood is divided into smaller units, with a unit area of ​​no more than 0.25 square meters, to ensure that it can fit the curved surface without generating excessive internal stress. According to the layout diagram, the cut bamboo plywood is assembled and attached to the surface of the steel keel, with the overlap width of adjacent panels being no less than 5 cm. The bamboo plywood is fixed using cement nails with a diameter of 2.8 to 3.5 mm or galvanized iron wire with a diameter of 1.6 to 2.0 mm, with the spacing between the fixing points no more than 15 cm. During the assembly process, a measuring tool is used to check the deviation of the surface geometry from the design value in real time to ensure that the deviation is within 5 mm. The purpose of this step is to use precise surface fitting and cutting technology to produce a template that can accurately reflect the design shape, laying the foundation for subsequent concrete pouring.

[0060] The specific implementation of step S04 is to lay and secure the flexible formwork. First, the flexible formwork is cut to the appropriate size based on the geometry of the elbow-shaped flow channel, leaving a 10-15 cm overlap margin when cutting. The flexible formwork is then laid on the outside of the bamboo plywood. The flexible formwork should be made of a high-strength composite material with a thickness of 1.5-2.0 mm, which has good toughness and waterproof properties. A galvanized iron sheet with a thickness of 0.5-0.8 mm is attached to the outside of the flexible formwork. The galvanized iron sheet serves to increase the rigidity and load-bearing capacity of the formwork and prevent local deformation during the fluidized solidified soil filling process. High-strength straps or special clamps with a spacing of 20-30 cm are used to secure the flexible formwork and the galvanized iron sheet to the bamboo plywood. The securing torque is controlled at 8-12 Nm to ensure that the flexible formwork fits tightly to the bamboo plywood surface and prevent shifting or wrinkling during the pouring process. The span value of the formwork is measured using a measuring instrument. The maximum span value should not exceed ±5 mm of the design value. Any areas that exceed the range are adjusted or reinforced. The purpose of this step is to improve the overall performance of the formwork through the combination of flexible formwork and galvanized iron sheets, ensuring that it can withstand the pressure and impact during the process of fluidized solidified soil filling and concrete pouring.

[0061] The specific implementation of step S05 is to prepare fluidized solidified soil of appropriate strength. First, use a thermometer to measure the ambient temperature, which is generally between 5 and 35°C. The admixture dosage is determined based on the ambient temperature. When the temperature is between 5 and 15°C, the admixture dosage is 1.0% to 1.5% of the mass of the cementitious material; when the temperature is between 15 and 25°C, the admixture dosage is 0.8% to 1.2%; and when the temperature is between 25 and 35°C, the admixture dosage is 0.6% to 1.0%. The water-cement ratio is calculated. Typically, the water-cement ratio is controlled between 0.45 and 0.55. A higher water-cement ratio promotes fluidity but reduces strength; a lower water-cement ratio has the opposite effect. The rheological equation for fluidized solidified soil is used to predict its flow properties and setting time. This equation, based on the Bingham fluid model, considers the effects of factors such as the water-cement ratio, ambient temperature, and admixture dosage on rheological parameters, and can accurately predict key parameters of fluidized solidified soil, such as yield stress and plastic viscosity. Adjust the mix proportions based on the predicted results to ensure the fluidized solidified soil has good pumpability and an appropriate setting time. Prepare the fluidized solidified soil according to design requirements, using a composite material of low-heat cement and fly ash as the cementitious material, medium sand as the fine aggregate, and appropriate amounts of water reducer and retarder. Mechanical agitation is used to ensure a uniform mix, ultimately ensuring a post-curing strength of 0.8 to 1.2 MPa. This step aims to produce a fluidized solidified soil with good fluidity and moderate strength through scientific proportioning and precise control, providing effective support for the elbow runner formwork.

[0062] The specific implementation method of step S06 is to fill the fluidized solidified soil. First, the minimum thickness of the fluidized solidified soil filling is calculated according to the support bearing equation. This equation is based on the lateral pressure theory and the principle of material mechanics, taking into account factors such as concrete pouring height, density, pouring rate, and the calculated minimum thickness is usually 20 to 40 centimeters. Use a pumping device to inject the prepared fluidized solidified soil into the template. The pumping pipe diameter is selected to be 100 to 150 mm, and the pumping pressure is controlled at 0.3 to 0.5 MPa. Pour in layers from low to high to avoid bubbles and segregation. The thickness of each layer is controlled at 30 to 50 centimeters, and the pouring time of adjacent layers is no more than 2 hours to ensure good interlayer bonding. Use a vibrating rod with a diameter of 50 to 70 mm to vibrate gently. The vibration time is controlled at 10 to 15 seconds, and the vibration point spacing is 400 to 600 mm to ensure that the fluidized solidified soil fully fills the template internal space and eliminates bubbles. Monitor the pouring rate in real time and control it between 0.5 and 1.0 meters per hour to avoid deformation or damage to the formwork due to excessive pouring speed. Also monitor form deformation. If deformation exceeds 5 mm, pause pouring and resume after the formwork stabilizes. This step ensures that the fluidized, solidified soil evenly fills the formwork through scientific pouring methods and strict process control, forming a stable and reliable support structure.

[0063] The specific implementation method of step S07 is quality inspection and repair treatment. First, the rheological equation of the fluidized solidified soil is used to calculate its setting time, taking into account factors such as ambient temperature, water-cement ratio and admixture dosage. The general setting time is 12 to 24 hours. After the fluidized solidified soil reaches the initial setting state, check whether there are defects such as cracks, bulges or depressions on the surface of the formwork, and take corresponding repair measures for the defects found: for cracks, use epoxy resin glue for pouring repair; for bulges, use mechanical means to flatten or partially demolish and rebuild; for depressions, use fine stone concrete to fill and repair. The surface flatness deviation after repair should not exceed 5 mm / 3 meters, and local mutations should not exceed 2 mm. Use a rebound hammer to measure the actual strength of the fluidized solidified soil, take the average value of 5 measuring points, and ensure that its strength reaches the design requirement of 0.8 to 1.2 MPa. If the strength does not meet the requirements, it is necessary to increase the curing time or take reinforcement measures. The formwork's stability and overall rigidity were checked to confirm that it met the requirements for subsequent concrete pouring. This inspection included manual push-pull tests and load tests. Under a localized concentrated load of 200 kg, the formwork's maximum deformation should not exceed 3 mm. This step ensures the quality and stability of the formwork system through comprehensive inspection and necessary repairs, creating optimal conditions for concrete pouring.

[0064] The specific implementation of step S08 involves pouring concrete and removing the formwork. First, the concrete pouring height and density are calculated. Typically, the concrete density is 2400 kg / m³, and the pouring height is determined based on the elbow channel design. A safety factor is determined, typically ranging from 1.5 to 2.0, to account for uncertainties such as material heterogeneity, construction errors, and dynamic loads. The fluidized soil fill thickness is verified to meet the load-bearing requirements using the support-bearing equation. This equation, based on the theory of pressure distribution in material mechanics, considers the relationship between the lateral pressure of concrete and the compressive strength of the fluidized soil. Concrete pouring is performed according to standard construction techniques, with a concrete grade of no less than C30, a slump of 160 to 200 mm, and a pouring rate of 0.3 to 0.5 m / h. Vibration is performed using an insert vibrator to ensure that the concrete density meets the requirements. Once the concrete reaches 70% of its design strength, a 0.8 to 1.2 kW electric pick is used to carefully remove the fluidized soil along the elbow channel contour, maintaining a depth of 30 to 50 mm to avoid damaging the concrete surface. Next, the flexible formwork, galvanized iron sheets, and bamboo plywood are removed, starting with the outer layers and then the inner layers, ensuring minimal damage to the concrete surface. A wire brush is used to clean the remaining formwork and fluidized solids from the elbow runner, revealing a smooth concrete surface. This step ensures the quality and surface finish of the elbow runner through a rigorous concrete pouring and formwork removal process.

[0065] The specific implementation method of step S09 is quality inspection and acceptance. First, the construction records and quality inspection reports are sorted out, including material inspection reports, construction process records, quality inspection data, etc., to form a complete quality control file. Use precision measuring instruments to check the dimensions of the elbow flow channel, including key dimensions such as inlet diameter, outlet diameter, and axis length. The dimensional error is controlled within ±10 mm of the design value. Use a 3-meter ruler to measure the surface flatness. The flatness deviation is controlled within 5 mm / 3 meters, and local mutations do not exceed 2 mm. Use a rebound hammer to test the surface strength of the concrete, take the average value of 10 measuring points, and the strength is not less than 95% of the design value. Use an infrared thermal imager to detect whether there are defects such as cracks or honeycomb surfaces in the elbow flow channel, and repair them in time if defects are found. Record the actual geometric parameters of the elbow flow channel, including cross-sectional dimensions, axis curvature, etc., compare them with the design values, and evaluate the impact of deviations on hydraulic performance. Use computational fluid dynamics software to perform numerical simulation to test whether the hydraulic performance of the actually constructed elbow flow channel meets the design requirements. The simulation results show that the head loss should not exceed 10% of the design value. Submit all test data and acceptance documents to the supervisor for inspection and verification to confirm that the elbow channel quality meets the design requirements and relevant specifications and standards. The purpose of this step is to ensure that the elbow channel's geometric dimensions, surface quality, and hydraulic performance meet the requirements of use through a comprehensive and rigorous quality inspection and acceptance process.

[0066] The mathematical model or calculation process involved in the present invention is described in detail below.

[0067] The surface fitting equation involved in step S01 is a mathematical expression for determining the arrangement of steel bar keels and the cutting size of bamboo plywood, and is specifically expressed as follows:

[0068]

[0069] Where S(u, v) is the parametric equation of the elbow flow channel surface; P i，j is the control point matrix; and are the nth and mth degree B-spline basis functions in the u and v directions respectively; u and v are the coordinates in the parameter space, and their value range is [0, 1]; n and m are the orders in the u and v directions respectively, and their values ​​are generally 3 or 4.

[0070] Among them, the B-spline basis function is defined recursively:

[0071]

[0072]

[0073] Where u i is the i-th element of the node vector; k is the order of the basis function, and its value range is 1≤k≤n.

[0074] Control point matrix P i，j The method of obtaining is to fit the geometric shape of the elbow flow channel through the least squares method. The calculation formula is:

[0075]

[0076] Where Q l are the coordinates of the sampling points on the elbow flow surface; L is the total number of sampling points; ||·|| represents the Euclidean norm.

[0077] This surface fitting equation expresses the geometry of the elbow flow channel as a parametric surface. Based on the theory of non-uniform rational B-splines (NURBS), it can accurately describe complex three-dimensional surfaces. The B-spline basis functions in the equation provide local control characteristics, so that modifications to the control points only affect the local area of ​​the surface, which is conducive to local adjustment. Least squares fitting ensures the best match between the surface and the actual geometry, and the control point matrix directly determines the shape and smoothness of the surface. The application of this equation makes the mathematical description of complex surfaces feasible and provides a theoretical basis for the precise production of templates.

[0078] The minimum support point covering algorithm used in step S02 is an optimization algorithm based on graph theory, and its mathematical expression is as follows:

[0079] Given an undirected graph G = (V, E), where V represents the discretized node set of the elbow flow surface and E represents the connection relationship between nodes. Define the dominating set For any v∈VD, there exists u∈D such that (u, v)∈E. The minimum support point cover problem is to solve the minimum set D that satisfies the dominance condition.

[0080] This problem can be formalized as an integer programming problem:

[0081]

[0082] Constraints:

[0083]

[0084]

[0085] Where n is the total number of nodes; x i is a decision variable, when x i =1 indicates that node i is selected into the dominating set D, otherwise x i =0; N(i) represents the set of neighbor nodes of node i.

[0086] In order to consider the importance difference of nodes, the weight coefficient w is introduced i , modify the objective function to:

[0087]

[0088] Where w i Represents the weight of node i, which can be determined based on factors such as the curvature and stress magnitude of the node. Usually, the weight is smaller where the curvature is larger, and the range is [0.5, 2.0].

[0089] The core concept of this algorithm is to use graph theory's dominating set theory to find the minimum dominating set that covers all nodes, thereby determining the optimal placement of steel studs. The introduction of weight coefficients allows the algorithm to differentiate node placement based on their importance, minimizing rebar usage while ensuring support strength. This algorithm addresses the material waste caused by overly dense or irrational rebar placement in traditional methods, improving cost-effectiveness and construction efficiency.

[0090] The rheological equation of the fluidized solidified soil in step S05 describes the rheological characteristics of the fluidized solidified soil, and the mathematical expression is as follows:

[0091]

[0092] Where, τ is the shear stress, unit is Pa; τ0 is the yield stress, unit is Pa; μ p is the plastic viscosity, in Pa·s; is the shear rate, in s -1 ; η is the nonlinear coefficient, unit is Pa·s 2 .

[0093] The yield stress τ0 is related to the water-cement ratio, admixture dosage and ambient temperature, and the calculation formula is:

[0094]

[0095] Where w / c is the water-cement ratio, dimensionless; A is the admixture dosage, expressed as a percentage of the mass of the cementitious material; T is the ambient temperature, in °C; α1, β1, γ1, and δ1 are fitting coefficients, whose values ​​are determined by experiments. Generally, the value range of α1 is [80, 120], the value range of β1 is [1.8, 2.2], the value range of γ1 is [0.8, 1.2], and the value range of δ1 is [0.01, 0.03].

[0096] Plastic viscosity μ p The calculation formula is:

[0097]

[0098] Where α2, β2, γ2 and δ2 are fitting coefficients, which are determined through experiments. Generally, the value range of α2 is [30, 50], the value range of β2 is [1.5, 1.8], the value range of γ2 is [0.6, 0.9], and the value range of δ2 is [0.008, 0.015].

[0099] The calculation formula of the nonlinear coefficient η is:

[0100]

[0101] Where α3, β3, γ3 and δ3 are fitting coefficients, which are determined through experiments. Generally, the value range of α3 is [5, 10], the value range of β3 is [1.0, 1.3], the value range of γ3 is [0.3, 0.5], and the value range of δ3 is [0.005, 0.01].

[0102] Solidification time t of fluidized solidified soil s It is related to the ambient temperature, water-cement ratio and admixture dosage. The calculation formula is:

[0103]

[0104] Where, t s is the solidification time in hours; λ1, λ2, λ3 and λ4 are fitting coefficients determined by experiments. Generally, the value range of λ1 is [20, 30], the value range of λ2 is [0.8, 1.2], the value range of λ3 is [2.0, 3.0], and the value range of λ4 is [0.03, 0.05].

[0105] Strength after curing f cu It is related to age t, water-cement ratio and ambient temperature. The calculation formula is:

[0106]

[0107] Where, f cu is the strength after curing, in MPa; f0 is the ultimate strength, in MPa; k and n are fitting coefficients; t is the age, in days; t0 is the reference age, which is 1 day.

[0108] The calculation formula of ultimate strength f0 is:

[0109]

[0110] Where φ1, φ2, and φ3 are fitting coefficients, which are determined through experiments. Generally, the value range of φ1 is [2.0, 3.0], the value range of φ2 is [1.5, 2.0], and the value range of φ3 is [0.01, 0.02].

[0111] The fitting coefficients k and n are obtained by experimentally measuring the strength of fluidized solidified soil at different ages, and then fitting them using the nonlinear regression method. Generally, the value range of k is [0.5, 1.0], and the value range of n is [0.3, 0.6].

[0112] The rheological equation for fluidized soil is a modified Bingham model that adds quadratic terms to account for nonlinear effects, providing a more accurate description of the rheological properties of fluidized soil. The yield stress, plastic viscosity, and nonlinear coefficient have a power-order relationship with the water-cement ratio because the water-cement ratio affects the concentration of the cement paste and the interaction between particles. They have a linear relationship with the admixture dosage, reflecting the linear effect of admixtures on the dispersion of cement particles. They have an exponential relationship with temperature, consistent with the Arrhenius law, where increased temperature accelerates chemical reactions and enhances particle thermal motion. Setting time has a power-order relationship with the water-cement ratio, indicating the influence of moisture content on the hydration reaction rate. They are positively correlated with the admixture dosage, reflecting the retarding effect of the admixture. They have an exponential relationship with temperature, consistent with the temperature sensitivity of cement hydration reactions. Strength development is modeled using an exponential function, which describes the nonlinear growth of strength with age. The relationship between ultimate strength and the water-cement ratio and temperature reflects the influence of the extent and rate of the hydration reaction on the ultimate strength. This equation comprehensively considers the influence of multiple factors on the performance of fluidized solidified soil, and provides theoretical guidance for the preparation of fluidized solidified soil with appropriate strength and fluidity.

[0113] The support bearing equation in step S06 is used to calculate the minimum thickness of the fluidized solidified soil filling, and the mathematical expression is as follows:

[0114]

[0115] Where, d min is the minimum thickness of fluidized solidified soil filling, in m; ψ is the safety factor, generally set to [1.5, 2.0]; K h is the lateral pressure coefficient, which is related to the concrete pouring rate; ρ c is the density of concrete, in kg / m 3 ; g is the acceleration due to gravity, which is 9.8m / s 2 ; H is the concrete pouring height, in m; f cu It is the strength of fluidized solidified soil, in Pa.

[0116] Side pressure coefficient K h The relationship with the pouring rate v is:

[0117] K h =K0·(1+ξ·v);

[0118] Where K0 is the static side pressure coefficient, which is generally taken as 0.3 to 0.4; ξ is the rate influence coefficient, which is generally taken as [1.0, 1.5]; v is the pouring rate, in m / h.

[0119] In order to consider the influence of template span on filling thickness, a correction term is introduced:

[0120]

[0121] Where, is the minimum thickness after correction, in m; ω is the span correction coefficient, generally taken as [0.1, 0.2]; L is the template span, in m; L0 is the reference span, which is 1 m.

[0122] Considering the influence of vibration on the side pressure, it is further modified to:

[0123]

[0124] Where, is the minimum thickness after considering the influence of vibration, in m; χ is the vibration influence coefficient, generally set to [0.2, 0.3]; I v It is the vibration intensity index, which is related to the power of the vibrating rod and the density of the vibration points. Its value range is generally [0, 1].

[0125] The support bearing equation is based on the pressure distribution theory in material mechanics and takes into account the balance between the concrete side pressure and the compressive strength of the fluidized solidified soil. 2 The term represents the parabolic distribution of lateral pressure with depth, which conforms to the principle of fluid statics; the safety factor ψ takes into account uncertain factors such as material strength discreteness and dynamic load; the lateral pressure coefficient K h Including the effect of pouring rate reflects the fluid properties of freshly poured concrete before initial setting. The correction term accounts for the effects of formwork span and vibration on support thickness, making the calculation more accurate and secure. This equation makes the determination of fluidized solidified soil fill thickness more scientific, ensuring sufficient support strength while avoiding material waste.

[0126] The rheological equation of the fluidized solidified soil in step S07 further describes the change of the rheological properties of the fluidized solidified soil over time, which can be expressed as a time-dependent modified Bingham model:

[0127]

[0128] Where, τ(t) is the shear stress at time t, in Pa; τ0(t), μ p (t) and η(t) are the yield stress, plastic viscosity and nonlinear coefficient at time t, respectively.

[0129] The changes of these parameters over time can be expressed as:

[0130]

[0131]

[0132]

[0133] Where, t r is the reference time, which is 1 hour; κ1, κ2, κ3 and m1, m2, m3 are fitting coefficients, which are determined through experiments. Generally, the value range of κ1, κ2, κ3 is [5, 10], and the value range of m1, m2, m3 is [1.5, 2.5].

[0134] The solidification degree of fluidized solidified soil can be expressed by the apparent viscosity μ app express:

[0135]

[0136] The critical point at which the fluidized solidified soil changes from the fluid state to the solidified state can be defined as the point at which the apparent viscosity reaches a certain critical value μ cr The time, that is:

[0137] μ app (t s )=μ cr ;

[0138] Where, t s is the solidification time, in hours; μ cr is the critical apparent viscosity, generally taken as 10 5 Pa·s.

[0139] By solving the above equation, the setting time of fluidized soil can be determined. This equation describes the temporal evolution of the rheological parameters of fluidized soil and reflects the changes in the microstructure during cement hydration. The power-order growth pattern of yield stress, plastic viscosity, and nonlinear coefficient over time reflects the acceleration and deceleration characteristics of the cement hydration reaction. The definition of apparent viscosity comprehensively considers the effect of shear rate on rheological behavior, and the introduction of critical viscosity provides a method for quantitatively determining the setting state. The application of this equation allows for the precise prediction of the setting process of fluidized soil, providing a theoretical basis for time scheduling and quality control during construction.

[0140] Formwork deformation detection and repair involve elastic mechanics equations. When the formwork is subjected to fluid solidification soil pressure, its deformation can be expressed as:

[0141]

[0142] Where w(x, y) is the deflection of the template at point (x, y), in m; a and b are the length and width of the template, in m; a ij is the deflection coefficient, which is determined by the boundary conditions and load conditions.

[0143] For a uniformly distributed load q, the deflection coefficient a ij The calculation formula is:

[0144]

[0145] Where D is the bending stiffness of the template, in N·m, and the calculation formula is:

[0146]

[0147] Where E is the elastic modulus of the template material, in Pa; h is the template thickness, in m; ν is the Poisson's ratio of the template material, dimensionless.

[0148] The maximum deflection of the template usually occurs at the center point (a / 2, b / 2), and the calculation formula is:

[0149]

[0150] Where L is the characteristic length of the template, in m; I is the cross-sectional inertia moment of the template, in m 4 .

[0151] When the maximum deflection exceeds the allowable value, reinforcement is required. The deflection after reinforcement can be expressed as:

[0152]

[0153] Where w reinforced (x, y) is the deflection of the template at point (x, y) after reinforcement, in m; β is the reinforcement effect coefficient, generally taken as [0.6, 0.8]; (EI) reinforced and (EI) original are the bending stiffness of the formwork before and after reinforcement, in N·m 2 .

[0154] This elastic mechanics equation is based on the theory of small deformation and uses a sine series to represent the deformation of the formwork, which is consistent with the deflection distribution characteristics of rectangular plates under simply supported boundary conditions. The deflection coefficient is proportional to the load and inversely proportional to the bending stiffness, reflecting the influence of material and geometric properties on deformation. The bending stiffness is proportional to the material elastic modulus and the cube of the thickness, indicating that the thickness has a significant effect on the bending stiffness. The reinforcement effect model takes into account the ratio of the original stiffness to the reinforcement stiffness, as well as the effectiveness of the reinforcement method. The application of these equations makes the prediction and control of formwork deformation more accurate, providing a theoretical basis for judging the stability of the formwork and determining whether reinforcement is necessary.

[0155] The calculation of the concrete lateral pressure in step S08 involves the principles of fluid statics and material mechanics, and the mathematical expression is as follows:

[0156] p(z)=K h ·ρ c ·g·z;

[0157] Where p(z) is the lateral pressure at depth z, in Pa; K h is the lateral pressure coefficient; ρ c is the density of concrete, in kg / m 3 ; g is the acceleration due to gravity, which is 9.8m / s 2 ; z is the depth from the concrete surface, in meters.

[0158] Considering the setting characteristics of concrete, the change of lateral pressure with time can be expressed as:

[0159]

[0160] Where p(z, t) is the lateral pressure at depth z and time t, in Pa; θ is the pressure attenuation coefficient, which is related to factors such as concrete mix ratio and temperature, and is generally taken as [0.1, 0.3]h -1 ; t0 is the time when concrete begins to solidify, in hours.

[0161] The total pressure on the template can be obtained by integrating the pressure on the opposite side along the depth:

[0162]

[0163] Where F is the total pressure on the formwork, in N; H is the concrete pouring height, in m; w is the formwork width, in m.

[0164] The shear stress borne by the fluidized solidified soil support layer can be expressed as:

[0165]

[0166] Where, τs A is the shear stress borne by the fluidized solidified soil support layer, in Pa; s is the contact area, in m 2 ; L is the circumference of the contact surface, in meters.

[0167] In order to ensure that the fluidized solidified soil support layer does not suffer shear failure, the following conditions should be met:

[0168]

[0169] Where, f cu is the strength of fluidized solidified soil, in Pa; ψ is the safety factor.

[0170] This equation is based on the principles of fluid statics and considers concrete as a Bingham fluid with a certain yield stress, where the lateral pressure increases linearly with depth. The exponential decay model, which takes into account the setting characteristics of concrete, reflects the transition process of concrete from a fluid state to a solid state. The total pressure integral formula comprehensively considers the lateral pressure distribution and the geometric dimensions of the formwork, providing a basis for calculating the force that the support layer needs to withstand. Shear stress calculation and strength verification ensure that the fluidized solidified soil support layer has sufficient bearing capacity. The application of these equations makes the design of the support system more reasonable, ensuring construction safety while avoiding the waste of resources caused by overdesign.

[0171] The hydraulic performance evaluation in step S09 involves fluid mechanics calculations, mainly examining the head loss and flow field distribution of the elbow flow channel. The mathematical expression is as follows:

[0172] The calculation formula for the head loss of the elbow flow channel is:

[0173]

[0174] Where h L is the head loss, in m; ξ is the local loss coefficient; v is the average flow velocity, in m / s; g is the acceleration of gravity, which is 9.8 m / s 2 .

[0175] The local loss coefficient ξ is related to the flow channel angle α, the flow channel section ratio β and the axis curvature radius R. The calculation formula is:

[0176]

[0177] Wherein, α is the flow channel angle, in degrees; β is the area ratio of the outlet section to the inlet section; R is the axis curvature radius, in m; D is the inlet diameter, in m; C1, C2, C3, and C4 are fitting coefficients, determined by experiments or numerical simulations. Generally, the value range of C1 is [0.1, 0.2], the value range of C2 is [1.0, 1.2], the value range of C3 is [0.3, 0.5], and the value range of C4 is [0.6, 0.8].

[0178] Considering the influence of the surface roughness of the elbow flow channel, the correction formula is:

[0179]

[0180] Where, ξ * is the loss coefficient after considering the influence of surface roughness; μ is the roughness influence coefficient, which is generally taken as [30, 50]; ε is the surface roughness, in m.

[0181] When the actual geometric parameters deviate from the design values, the change in head loss can be expressed as:

[0182]

[0183] Where Δh L is the change in head loss; Δα, Δβ and ΔR are the deviations of the flow channel angle, cross-sectional ratio and curvature radius, respectively.

[0184] The flow field distribution inside the flow channel can be calculated by the Reynolds-averaged NS equation, where the turbulence model adopts the k-ε two-equation model:

[0185]

[0186] Where u i is the velocity component; p is the pressure; μ is the dynamic viscosity; ρ is the density; is the Reynolds stress.

[0187] Reynolds stress is calculated by turbulent viscosity μ t calculate:

[0188]

[0189] Where k is the turbulent kinetic energy; μ t is the turbulent viscosity, C μ is a constant, taken as 0.09; ε is the turbulent dissipation rate.

[0190] The fluid performance evaluation index of elbow flow channel includes energy loss coefficient K E :

[0191]

[0192] and the flow field uniformity index σ v :

[0193]

[0194] Where A is the cross-sectional area of ​​the flow channel; v is the local flow velocity; v avg is the average flow velocity.

[0195] The criteria for determining whether hydraulic performance meets design requirements are:

[0196] And σ v ≤0.15;

[0197] Specifically, the principle of the present invention is: the technical principle of the present invention is based on the organic combination of three aspects: precise modeling, optimized support layout and innovative support materials, so as to achieve high-strength support for complex curved surface templates.

[0198] First, a precise three-dimensional model of the elbow-shaped flow channel was constructed using Building Information Modeling software, enabling a parametric description of the complex curved surface structure. Using surface fitting equations, key parameters such as the design flow rate, flow channel angle, inlet diameter, outlet diameter, and the curvature radius of the flow channel axis were converted into three-dimensional surface expressions, providing a precise mathematical basis for formwork fabrication and support layout. This parametric model shifted support design from traditional empirical construction to precise calculations, laying the foundation for improved support strength.

[0199] Secondly, a minimum support point coverage algorithm was used to discretize the elbow channel surface, transforming the continuous surface into a node network. A graph-based optimization algorithm was then used to determine the optimal reinforcement layout that met the support strength requirements. This algorithm scientifically analyzed the stress characteristics of each point on the surface, optimized material distribution while ensuring overall support strength, and added reinforcement ribs at the surface transition points where stress is concentrated, forming a mechanically sound support structure and significantly improving the overall strength of the support system.

[0200] The most innovative feature is the application of a fluidized solidified soil support system. This invention predicts the flow properties and setting time of fluidized solidified soil through the rheological equation, and calculates the required minimum filling thickness in combination with the support bearing equation. Fluidized solidified soil has good fluidity and controllable curing strength (0.8-1.2 MPa), and can completely fill the space between the formwork and the external support structure to form an overall rigid support layer. This support system can evenly distribute the concrete pouring pressure, prevent local stress concentration, and greatly improve the overall support strength of the formwork system.

[0201] By applying the support bearing equation, this invention quantitatively calculates the relationship between support thickness and concrete pouring pressure, ensuring that the fluidized solidified soil fill layer has sufficient bearing capacity under various working conditions. This support design method, based on mechanical calculations, reliably guarantees formwork support strength, effectively resolving the issue of insufficient support strength in traditional technologies.

[0202] A specific embodiment 1 of the present invention is provided below. The specific implementation of each step in this embodiment 1 is described in detail as follows.

[0203] The specific implementation of step S01 is to construct a three-dimensional model of the elbow flow channel using building information modeling software. First, basic parameters such as the design flow rate, flow channel angle, inlet diameter, outlet diameter, and flow channel axis curvature radius are input. The flow characteristics of the fluid in the elbow flow channel are determined using the principles of computational fluid dynamics. The geometric shape of the elbow flow channel is determined using the optimal streamline method to reduce head loss and vortex generation. The geometric shape of the elbow flow channel is accurately expressed using a surface fitting equation, which is mathematically expressed as: Where S(u, v) is the parametric equation of the elbow flow channel surface; P i，j is the control point matrix; and are the nth and mth degree B-spline basis functions in the u and v directions, respectively; u and v are the coordinates in the parameter space, with a value range of [0, 1]; n and m are the orders in the u and v directions, respectively, and are generally 3 or 4. This surface fitting equation is based on the non-uniform rational B-spline (NURBS) theory and can accurately describe complex three-dimensional surfaces, providing an accurate geometric basis for formwork design and steel keel layout. Then, the spatial support structure optimization algorithm is used to determine the layout of the steel keel. This algorithm is based on the principles of structural mechanics and uses iterative calculations to find the optimal steel layout that meets the strength requirements. Finally, the finite element analysis method is used to verify the structural strength and stability of the model, and local reinforcement design is carried out for stress concentration areas, generating detailed construction drawings and material lists. The purpose of this step is to provide an accurate technical basis for subsequent construction through accurate three-dimensional model design, ensuring that the hydraulic and structural performance of the elbow flow channel meet the design requirements.

[0204] The specific implementation method of step S02 is to optimize the layout of the steel keel based on on-site measurement and layout. First, use a total station or theodolite to accurately measure the site, determine the spatial position of the elbow flow channel based on the building information model, mark the contour line and key control points of the elbow flow channel, and the distance between control points shall not exceed 0.5 meters. Then, a discretization method is used to divide the surface of the elbow flow channel into triangular grids with a grid size of 10 to 20 cm, and a node network is constructed as the basis for the layout of the steel keel. Then, the minimum support point coverage algorithm is applied to determine the optimal layout position of the steel keel. The algorithm can be formalized as an integer programming problem: Constraints: Where n is the total number of nodes; x i is a decision variable, when x i =1 indicates that node i is selected into the dominating set D, otherwise x i =0; N(i) represents the set of neighbor nodes of node i; w i The weight of node i is determined based on factors such as the curvature and stress level at the node's location. Typically, the weight is smaller in areas with greater curvature, ranging from [0.5 to 2.0]. Based on the algorithm's calculations, reinforcement bars are added at curved corners and areas of stress concentration, with spacing between the bars at 50% to 70% of the standard spacing to ensure that the formwork does not deform or fail due to excessive localized stress during concrete pouring. This step optimizes the placement of the reinforcement bars through a scientific algorithm, ensuring structural strength while reducing material usage and improving construction efficiency.

[0205] The specific implementation of step S03 is to make and install the template based on the surface fitting equation. First, according to the discretized surface node coordinates, the B-spline surface fitting method is used to construct a mathematical model of the elbow flow channel surface and obtain the surface parameter equation. Then, according to the definition of the B-spline basis function: Where u i is the i-th element of the node vector; k is the order of the basis function, ranging from 1 ≤ k ≤ n. CNC cutting equipment is used to cut the bamboo plywood into the desired size and shape according to the fitted surface parameters, with cutting accuracy within ±2 mm. For complex curved areas, the bamboo plywood is divided into smaller units, with a unit area not exceeding 0.25 square meters, to ensure that it can conform to the curved surface without generating excessive internal stress. The cut bamboo plywood is assembled and bonded to the surface of the steel keel according to the layout diagram, with the overlap width of adjacent panels not less than 5 cm. The bamboo plywood is secured using cement nails with a diameter of 2.8 to 3.5 mm or galvanized iron wire with a diameter of 1.6 to 2.0 mm, with the spacing between the fixing points not exceeding 15 cm. During the assembly process, measurement tools are used to check the surface geometry for deviations from the design value in real time, ensuring that the deviation is within 5 mm. The purpose of this step is to produce a template that accurately reflects the designed shape through precise surface fitting and cutting techniques, laying the foundation for subsequent concrete pouring.

[0206] The specific implementation of step S04 is the same as above and will not be described in detail here.

[0207] The specific implementation method of step S05 is to prepare fluidized solidified soil with suitable strength. First, use a thermometer to measure the ambient temperature, which is usually between 5 and 35°C. Determine the admixture dosage according to the ambient temperature. When the temperature is 5 to 15°C, the admixture dosage is 1.0% to 1.5% of the mass of the cementitious material; when the temperature is 15 to 25°C, the admixture dosage is 0.8% to 1.2%; when the temperature is 25 to 35°C, the admixture dosage is 0.6% to 1.0%. Calculate the water-cement ratio. Usually, the water-cement ratio is controlled between 0.45 and 0.55. A higher water-cement ratio is conducive to fluidity but will reduce strength; a lower water-cement ratio is the opposite. Apply the rheological equation of fluidized solidified soil to predict its flow properties and setting time. The equation is expressed as: Where, τ is the shear stress, unit is Pa; τ0 is the yield stress, unit is Pa; μ p is the plastic viscosity, in Pa·s; is the shear rate, in s -1 ; η is the nonlinear coefficient, unit is Pa·s 2 The calculation formula of yield stress τ0 is: Where w / c is the water-cement ratio, dimensionless; A is the admixture dosage, expressed as a percentage of the mass of the cementitious material; T is the ambient temperature, in °C; α1, β1, γ1, and δ1 are fitting coefficients determined experimentally. p The calculation of the nonlinear coefficient η is similar. The setting time t of fluidized solidified soil s The calculation formula is: Where, t s is the setting time in hours; λ1, λ2, λ3, and λ4 are fitting coefficients determined experimentally. Adjust the mix ratio based on the predicted results to ensure that the fluidized solidified soil has good pumping performance and a suitable setting time. Prepare the fluidized solidified soil according to the design requirements. Use a composite material of low-heat cement and fly ash as the cementitious material, medium sand as the fine aggregate, and add an appropriate amount of water reducer and retarder. Ensure uniform mixing through mechanical stirring, and ultimately ensure that the strength after curing is between 0.8 and 1.2 MPa. The purpose of this step is to prepare fluidized solidified soil with good fluidity and moderate strength through scientific proportioning and precise control, providing effective support for the elbow-type flow channel formwork.

[0208] The specific implementation of step S06 is to fill the fluidized solidified soil. First, the minimum thickness of the fluidized solidified soil filling is calculated according to the support bearing equation. The equation is: Where, d min is the minimum thickness of fluidized solidified soil filling, in m; ψ is the safety factor, generally set to [1.5, 2.0]; K h is the lateral pressure coefficient, which is related to the concrete pouring rate; ρ cis the density of concrete, in kg / m 3 ; g is the acceleration due to gravity, which is 9.8m / s 2 ; H is the concrete pouring height, in m; f cu is the strength of fluidized solidified soil, in Pa. Lateral pressure coefficient K h The relationship with the pouring rate v is: K h =K0·(1+ξ·v), where K0 is the static side pressure coefficient, generally 0.3-0.4; ξ is the rate influence coefficient, generally [1.0, 1.5]; and v is the pouring rate in m / h. To account for the effects of formwork span and vibration, the minimum thickness needs to be modified: Where, and are the minimum thickness after considering the span and vibration effect; ω is the span correction coefficient; L is the template span; L0 is the reference span; χ is the vibration effect coefficient; I v It is the vibration strength index. Then use pumping equipment to inject the prepared fluidized solidified soil into the interior of the formwork. The pumping pipe diameter is selected to be 100-150 mm, and the pumping pressure is controlled at 0.3-0.5 MPa. Pour in layers from low to high to avoid bubbles and segregation. The thickness of each layer is controlled at 30-50 cm. The pouring time of adjacent layers should not exceed 2 hours to ensure good bonding between layers. Use a vibrating rod with a diameter of 50-70 mm to vibrate gently. The vibration time is controlled at 10-15 seconds, and the spacing between vibration points is 400-600 mm to ensure that the fluidized solidified soil fully fills the internal space of the formwork and eliminates bubbles. Monitor the pouring rate in real time and control it at 0.5-1.0 m / h to avoid deformation or damage to the formwork due to excessively fast pouring speed. The purpose of this step is to ensure that the fluidized solidified soil evenly fills the interior of the formwork through scientific pouring methods and strict process control to form a stable and reliable support structure.

[0209] The specific implementation of step S07 is quality inspection and repair processing. First, the rheological equation of fluidized solidified soil is used to calculate its setting time. This equation describes the change of rheological properties of fluidized solidified soil over time: Where τ(t) is the shear stress at time t; τ0(t), μ p (t) and η(t) are the yield stress, plastic viscosity and nonlinear coefficient at time t, respectively. The changes of these parameters with time can be expressed as: Where, t r is the reference time; κ1, κ2, κ3 and m1, m2, m3 are fitting coefficients. The solidification degree of fluidized solidified soil can be expressed by the apparent viscosity μ app express: When the apparent viscosity reaches the critical value μcr When the fluidized solidified soil is considered to have solidified: μ app (t s )=μ cr , where t s is the solidification time; μ cr is the critical apparent viscosity, generally taken as 10 5 Pa·s. After the fluidized solidified soil reaches the initial setting state, check whether there are cracks, bulges or depressions on the formwork surface, and take appropriate repair measures for any defects found. The elastic mechanics equation can be used to detect formwork deformation: Where w(x, y) is the deflection of the template at point (x, y); a and b are the length and width of the template respectively; a ij is the deflection coefficient. When the maximum deflection exceeds the allowable value, reinforcement is required. The surface flatness deviation after repair should not exceed 5 mm / 3 meters, and the local mutation should not exceed 2 mm. Use a rebound hammer to measure the actual strength of the fluidized solidified soil, take the average value of 5 measuring points, and ensure that its strength reaches the design requirement of 0.8~1.2MPa. The purpose of this step is to ensure the quality and stability of the formwork system through comprehensive inspection and necessary repair treatment, so as to create good conditions for concrete pouring.

[0210] The specific implementation of step S08 is concrete pouring and formwork removal. First, calculate the concrete pouring height and density. The concrete density is usually 2400 kg / m3, and the pouring height is determined according to the elbow flow channel design. Determine the safety factor, which is generally 1.5 to 2.0. The safety factor takes into account uncertain factors such as material heterogeneity, construction errors, and dynamic loads. The formula for calculating the concrete lateral pressure is: p(z) = K h ·ρ c ·g·z, where p(z) is the lateral pressure at depth z; K h is the lateral pressure coefficient; ρ c is the density of concrete; g is the acceleration of gravity; z is the depth from the concrete surface. Considering the setting characteristics of concrete, the change of lateral pressure over time can be expressed as: Where p(z, t) is the lateral pressure at depth z and time t; θ is the pressure attenuation coefficient; and t0 is the time when the concrete begins to set. The total pressure on the formwork can be obtained by integrating the lateral pressure along the depth: Where F is the total pressure on the formwork; H is the concrete pouring height; and w is the formwork width. The support load equation is then used to verify whether the fluidized soil fill thickness meets the load-bearing requirements. Concrete pouring is carried out according to standard construction techniques, with a concrete grade of no less than C30, a slump of 160-200 mm, and a pouring rate of 0.3-0.5 m / h. Vibration is performed using an insert vibrator to ensure that the concrete density meets the requirements. After the concrete reaches 70% of the design strength, a 0.8-1.2 kW electric pick is used to carefully remove the fluidized soil along the contour of the elbow runner, maintaining a depth of 30-50 mm to avoid damaging the concrete surface. The flexible formwork, galvanized iron sheeting, and bamboo plywood are then removed, starting with the outer layer and then the inner layer, ensuring minimal damage to the concrete surface. This step ensures the quality and surface finish of the elbow runner through scientific concrete pouring and formwork removal techniques.

[0211] The specific implementation method of step S09 is quality inspection and acceptance. First, the construction records and quality inspection reports are sorted out, including material inspection reports, construction process records, quality inspection data, etc., to form a complete quality control file. Use precision measuring instruments to check the dimensions of the elbow flow channel, including key dimensions such as inlet diameter, outlet diameter, and axis length. The dimensional error is controlled within ±10 mm of the design value. Use a 3-meter ruler to measure the surface flatness, and the flatness deviation is controlled within 5 mm / 3 meters, and the local mutation does not exceed 2 mm. Use a rebound tester to detect the surface strength of the concrete, take the average value of 10 measuring points, and the strength is not less than 95% of the design value. Use an infrared thermal imager to detect whether there are defects such as cracks or honeycomb surfaces in the elbow flow channel, and repair them in time if defects are found. Record the actual geometric parameters of the elbow flow channel, including cross-sectional dimensions, axis curvature, etc., compare them with the design values, and evaluate the impact of deviations on hydraulic performance. The hydraulic performance of the elbow flow channel is evaluated, and the head loss calculation formula is: Where h L is the head loss; ξ is the local loss coefficient; v is the average flow velocity; g is the acceleration of gravity. The local loss coefficient ξ is related to the flow channel angle α, the flow channel cross-sectional ratio β and the axis curvature radius R. The calculation formula is: Where α is the channel turning angle; β is the area ratio of the outlet section to the inlet section; R is the axis curvature radius; D is the inlet diameter; C1, C2, C3, and C4 are fitting coefficients. Considering the influence of the surface roughness of the elbow channel, the modified formula is: Where, ξ * is the loss coefficient after considering the influence of surface roughness; μ is the roughness influence coefficient; ε is the surface roughness. When there is a deviation between the actual geometric parameters and the design values, the change in head loss can be expressed as: Where Δh Lis the change in head loss; Δα, Δβ and ΔR are the deviations of the channel angle, cross-sectional ratio and curvature radius respectively. The flow field distribution inside the channel is calculated by the Reynolds averaged NS equation, and the evaluation indicators include the energy loss coefficient K E and flow field uniformity index σ v The criteria for determining whether hydraulic performance meets design requirements are: And σ v ≤0.15. Submit all test data and acceptance documents to the supervisory unit for acceptance to confirm that the quality of the elbow flow channel meets the design requirements and relevant specifications and standards. The purpose of this step is to ensure that the geometric dimensions, surface quality and hydraulic performance of the elbow flow channel meet the requirements of use through a comprehensive and rigorous quality inspection and acceptance procedure.

[0212] The main structures and devices involved in the elbow-shaped flow channel formwork support and reinforcement construction method finally obtained in this embodiment 1 are described in detail as follows: The elbow-shaped flow channel is a special-shaped water flow channel in a pumping station. Its longitudinal section is elbow-shaped and is usually composed of an inlet section 11, a curved section 13, and an outlet section 12. The inlet section has a circular or rectangular cross-section with a diameter or side length of 0.8 to 2.5 meters; the curved section is a transition section with a curvature radius of 1.5 to 3.0 times the inlet diameter, and the bending angle is usually 45° to 90°; the outlet section is connected to the water pump, and the cross-sectional shape matches the water pump inlet, with a diameter or side length of 0.6 to 2.0 meters. The inner wall of the entire flow channel is smooth, and the concrete surface roughness is no more than 0.3 mm to reduce head loss and vortex generation. The reinforced keel is the skeletal structure supporting the formwork. It consists of primary and secondary reinforcement. The primary reinforcement uses HRB400-grade threaded steel bars with a diameter of 16-25 mm, spaced 300-500 mm apart; the secondary reinforcement uses HRB400-grade threaded steel bars with a diameter of 12-16 mm, spaced 400-600 mm apart. The intersections of the primary and secondary reinforcements are tied or welded together to form a grid-like support framework. Reinforcement bars with a diameter of 16-20 mm are added at curved corners to increase local rigidity. Bamboo plywood, 15-20 mm thick, is used for formwork. It offers excellent strength and workability, and is coated with a release agent for easy demolding. Flexible formwork is made of a high-strength composite material with a thickness of 1.5-2.0 mm. It can adapt to complex curves and has a smooth interior surface, minimizing concrete surface defects. Fluidized solidified soil is a special support and filling material composed primarily of cement, fly ash, sand, water, and admixtures. The mass ratios are: 10% to 15% cement, 5% to 8% fly ash, 70% to 75% sand, 10% to 12% water, and 0.6% to 1.5% admixture. It exhibits excellent fluidity and moderate strength, making it easy to remove later. The scientific design and proper use of these structures and devices are key to the successful implementation of the elbow-type flow channel formwork support and reinforcement construction method.

[0213] It should be noted that the detailed explanations of the variables involved in the present invention are shown in Table 1(a) and Table 1(b).

[0214] Table 1(a) Variable Explanation Table

[0215]

[0216]

[0217] Table 1(b) Variable Explanation Table

[0218]

[0219] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station, characterized in that: include: Use building information modeling software to create a three-dimensional model of the elbow flow channel and determine the layout of the steel keel and the fluidized solidified soil filling scheme; On-site measurements and layout were conducted, and the minimum support point coverage algorithm was used to determine the optimal placement of the steel keel. The surface parameters of the elbow flow channel were calculated using surface fitting equations. The bamboo plywood was cut and assembled on the surface of the steel keel. Flexible formwork was laid and secured. The fluidized solidification soil was prepared. Inject the fluidized solidified soil into the formwork and pour it in layers; After the fluidized solidified soil solidifies, check the formwork surface to confirm that the stability and strength of the formwork meet the requirements for concrete pouring; After the concrete pouring is completed and reaches the designed strength, the fluidized solidified soil is removed and the formwork is dismantled; Check the surface quality of the elbow flow channel to ensure that it meets the design requirements.

2. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 1 is characterized in that: A three-dimensional model of the elbow-shaped flow channel was established using building information modeling software, including determining the spatial layout of the steel keel and the fluidized solidified soil filling plan, generating construction drawings and material lists, clarifying the template dimensions and steel bar specifications, and calculating the design flow rate, flow channel turning angle, inlet diameter, outlet diameter, and flow channel axis curvature radius.

3. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 2 is characterized in that: On-site measurement and layout include marking the elbow flow channel contour and key control points, discretizing the elbow flow channel surface into a node network, using the minimum support point coverage algorithm to determine the optimal layout of the steel keel, and adding reinforcement ribs at the turning points of the curved surface to maximize the structural support strength and minimize the amount of steel bars used.

4. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 3 is characterized in that: The surface parameters of the elbow-shaped flow channel are calculated using the surface fitting equation. The bamboo plywood is cut into the required size according to the surface parameters, assembled and attached to the surface of the steel keel according to the layout diagram, and fixed with cement nails or iron wire to ensure that the joints are tight and the surface is flat.

5. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 4 is characterized in that: Laying the flexible formwork includes laying the flexible formwork on the outside of the bamboo plywood, fitting the galvanized iron sheet, fixing it with straps or clamps to ensure that the flexible formwork fits tightly to the surface of the bamboo plywood to prevent displacement during pouring, and measuring the formwork span value before pouring the fluidized solidified soil.

6. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 5 is characterized in that: The preparation of fluidized solidified soil includes measuring the ambient temperature, determining the dosage of admixtures, calculating the water-cement ratio, predicting the flow properties and setting time through the rheological equation of fluidized solidified soil, preparing the fluidized solidified soil according to the design requirements, and ensuring that the strength after solidification is between 0.8 and 1.2 MPa.

7. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 6, characterized in that: Injecting the fluidized solidified soil into the formwork includes calculating the minimum filling thickness of the fluidized solidified soil based on the support bearing equation, injecting the fluidized solidified soil into the formwork using pumping equipment, pouring the fluidized solidified soil in layers from low to high, controlling the thickness of each layer to be 30 to 50 cm, using a vibrating rod to gently vibrate to ensure sufficient filling, and monitoring the pouring rate.

8. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 7, characterized in that: Checking the formwork surface after the fluidized solidified soil solidifies includes calculating the setting time using the rheological equation of the fluidized solidified soil. After the fluidized solidified soil solidifies, checking whether the formwork surface is damaged, performing necessary repairs, measuring the actual strength of the fluidized solidified soil, and confirming that the stability and strength of the formwork meet the requirements for concrete pouring.

9. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 8, characterized in that: After the concrete pouring is completed and reaches the design strength, the concrete pouring height and density are calculated, the safety factor is determined, and the thickness of the fluidized solidified soil filling is verified to meet the bearing requirements based on the support bearing equation. After the concrete pouring is completed and reaches the design strength, an electric pick is used to remove the fluidized solidified soil, the formwork is removed, and the surface quality of the elbow flow channel is checked.

10. The method for supporting and reinforcing the elbow-shaped flow channel formwork of a water conservancy project pump station according to claim 9, characterized in that: The minimum support point coverage algorithm is used to determine the minimum number of steel bar layout points that meet support strength requirements, reducing material usage and improving construction efficiency. The support bearing equation is a mathematical expression for calculating the minimum thickness required for the fluidized solidified soil fill layer to ensure that it can withstand the lateral pressure generated by concrete pouring without deformation or damage.

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