A design method for prefabricated reinforced concrete pavement structures in airports

Abstract

A design method for prefabricated reinforced concrete pavement structures in airports is proposed to establish a complete and effective reinforcement design method for prefabricated pavement structures, while considering the effects of temperature, foundation deformation, and fatigue. This provides a basis for studying the stress characteristics of prefabricated pavement panels and designing prefabricated reinforced concrete pavement structures in airports. The method includes the following steps: S1, obtaining airport pavement engineering design parameters, including aircraft parameters and pavement geotechnical parameters; S2, preliminary design of prefabricated pavement panels; S3, establishing finite element models of pavement structure elements, including: prefabricated pavement panel element model, cement-stabilized layer model, soil subgrade model using discrete soil springs, and finite element model of pavement panel connectors; S4, calculation of internal forces in prefabricated pavement panels; S5, verification of the bearing capacity of prefabricated pavement panels; S6, optimized design of reinforcement in prefabricated pavement panels; S7, verification of lifting conditions.

Description

Technical Field

[0001] This invention relates to transportation roadbed facilities, and in particular to a design method for prefabricated reinforced concrete pavement panels for highways and airport runways. Background Technology

[0002] Prefabricated pavement boasts sufficient strength and rigidity, good weather stability, a smooth surface, anti-slip properties, durability, and rapid repairability, thus attracting increasing attention from the engineering community both domestically and internationally. Based on materials, prefabricated pavement can be classified into four categories: reinforced concrete pavement, reinforced concrete pavement, prestressed reinforced concrete pavement, and ultra-high performance concrete pavement. Among these, reinforced concrete and prestressed reinforced concrete prefabricated pavement offer advantages such as high strength, large load-bearing capacity, and rapid and convenient construction. They are particularly suitable for use in various situations, including new airport construction, emergency expansion and renovation, and rapid repair and construction, making them the most appropriate prefabricated pavement systems for airports.

[0003] However, most rigid pavements in domestic airports are currently plain concrete or reinforced concrete, and their design methods are all based on plain concrete pavement design methods, which have been incorporated into relevant design standards and specifications. However, design methods for reinforced concrete pavements and prestressed reinforced concrete rigid pavements are still lacking. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a design method for prefabricated reinforced concrete pavement structures in airports, so as to establish a complete and effective reinforcement design method for prefabricated pavement structures, while considering the effects of temperature, foundation deformation and fatigue effects, and to provide a basis for studying the stress characteristics of prefabricated pavement panels and the design of prefabricated reinforced concrete pavement structures in airports. 。

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: This invention discloses a design method for a prefabricated reinforced concrete pavement structure for airports. The pavement structure includes, from bottom to top, a subgrade, a cement-stabilized layer, and a pavement layer. The pavement layer is formed by assembling precast pavement panels, which are either reinforced concrete or prestressed reinforced concrete pavement panels. Adjacent precast pavement panels are connected together by pavement panel connectors. The design method for this pavement structure includes the following steps: S1. Obtain airport runway engineering design parameters, including aircraft type parameters and pavement geotechnical parameters: (1) Aircraft parameters: Based on the design requirements, determine the aircraft parameters that need to be designed for the airport to be built, including the static load of the main wheels, tire pressure, and tire contact area; (2) Conduct geotechnical tests on pavement geotechnical parameters. Subgrade geotechnical parameters include subgrade reaction modulus K and subgrade Poisson's ratio μt. Cement stabilized pavement geotechnical parameters include resilient modulus Ec, cement stabilized layer Poisson's ratio μc and thickness. S2. Preliminary design of precast pavement panels: Combining transportation and hoisting capacity, processing and manufacturing difficulty and cost, comprehensive performance parameters and indicators, comparative analysis is conducted to determine the size of precast pavement panels and preliminary arrangement of reinforcing bars. S3. Establish a finite element model of the pavement structure, including: (1) Based on the basic assumptions of small deflection elastic thin plate, the precast track panel element model is established using elastic plate elements; (2) A cement-stabilized layer model was established using solid elements; (3) A soil foundation model was established using discrete soil springs; (4) A finite element model of the pavement panel connector was established using an elastic-plastic rod system model; (5) Establish the edge constraints of the precast pavement panels, and the number of modeling panels is 4×3; S4. Calculation of internal forces in precast pavement panels to determine the maximum bending moment. M d,max That is, based on the finite element model of the pavement structure element established in step S3, different load combinations are considered, including design wheel load, fatigue effect, and fatigue effect plus temperature gradient, to obtain the maximum bending moment value under the corresponding load combination. M d,max =m×M d1 + M d2 In the formula, m is the condition coefficient. M d1 For the maximum design bending moment, M d2 The maximum temperature flexural moment; S5. Calculation of the bearing capacity of the precast pavement slab, and the maximum bending moment under the corresponding load combination obtained in step S4. M d,max According to the current GB50010 Code for Design of Concrete Structures, the reinforcement design of prestressed concrete slabs should be carried out, determining the type, quantity, and distribution of prestressing tendons and steel bars; when the requirements are not met... S d≤ R d or W max≤ W d If necessary, return to step S2 and redesign the reinforcement of the precast pavement panel, where, S d This is the design value for the bending moment. R dThis is the design value for bending moment resistance. W max For the calculated value of the crack, W d Limits for cracks; S6. Optimization design of reinforcement of precast pavement panels: Based on influence surface analysis, the reinforcement of the edge area of ​​the precast pavement panels adopts a strengthened design, and the strengthened design area is determined by influence surface analysis. S7. Lifting condition calculation: On the precast pavement unit model established in step S4, the lifting stress level of the precast pavement is calculated according to the special tooling and lifting equipment. According to the current GB50666 Code for Construction of Concrete Structures, the gravity amplification factor during lifting is taken as 1.5. Its compressive stress is less than the standard value of concrete compressive strength, which meets the lifting requirements.

[0006] The beneficial effects of this invention are mainly reflected in the following aspects: I. A complete and effective design method for reinforcement of prefabricated pavement structures was established, which effectively solved the problem of reinforcement design for prefabricated reinforced concrete pavement structures in airports and provided a basis for studying the stress characteristics and laws of prefabricated pavement panels. At the same time, the influence of temperature, foundation deformation and fatigue effects were considered, filling a gap in the industry. Second, the design method is simple and versatile, and the calculation results are accurate. By combining finite element analysis with indoor and outdoor tests, an analytical model that better reflects the actual stress state of pavement structures is established. The calculation process is concise and comprehensive, taking into account the effects of temperature, self-weight, foundation deformation, and the interaction between adjacent slabs. It can truly reflect the actual stress state of the pavement slab, with a deviation of about 10% compared with field tests. Thirdly, a design method for prefabricated pavement panel connectors is proposed. A three-dimensional finite element model considering contact is established using the finite element method. Combined with model tests of concrete pavement panels with dowel bars, the stress in the cement concrete panel at the joint, the shear stress in the dowel bars, and the stress distribution at the interface between the dowel bars and the pavement panel are analyzed. This provides reference for the design and construction of dowel bars at pavement panel joints… IV. Introducing the influence surface calculation method significantly reduces the overall reinforcement of the pavement slab. Different machine models play a controlling role in different layouts and along different slab edge directions. Even for the same machine model, the load varies significantly at different load distribution locations. Designing based on the maximum load on one side is clearly uneconomical. Using the influence surface analysis method can significantly reduce the overall reinforcement. The reinforcement in the pavement slab edge areas needs to be strengthened, and the areas requiring strengthened reinforcement are determined by the influence surface analysis. Attached Figure Description

[0007] This instruction manual includes the following figures: Figure 1 This is a flowchart of a prefabricated prestressed concrete pavement structure design method according to the present invention; Figure 2 This is a plan view of the prestressed concrete pavement panel structure in an embodiment of the present invention; Figure 3 This is a side view of the prestressed concrete pavement panel structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the force transmission rod in an embodiment of the present invention; Figure 5 This is a schematic diagram of the pull rod structure in an embodiment of the present invention; Figure 6a , Figure 6b and Figure 6c This is a schematic diagram of the landing gear arrangement of a certain aircraft model in an embodiment of the present invention; Figure 7 This is a load envelope diagram of the prestressed concrete pavement slab in an embodiment of the present invention; Figure 8 This is a schematic diagram of the reinforcement zone of the prestressed concrete pavement slab in an embodiment of the present invention; Figure 9 This is a schematic diagram of the finite element model calculation of the channel panel of the present invention.

[0008] The figure shows the components and their corresponding markings: subgrade 10, graded crushed stone cement stabilized layer 11, filling layer 12, precast pavement panel 20, dowel bar 21, tie bar 22, pre-drilled hole for lifting sleeve 23, L-shaped steel bar 31, anchoring steel bar 32, weld 33, U-shaped steel bar 41, and ribbed reinforcement zone A at the edge of the slab. Detailed Implementation

[0009] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0010] Reference Figure 1 This invention discloses a design method for a prefabricated reinforced concrete pavement structure for airports. The pavement structure includes, from bottom to top, a subgrade, a cement-stabilized layer, and a pavement layer. The pavement layer is formed by assembling precast pavement panels, which are either reinforced concrete or prestressed reinforced concrete. Adjacent precast pavement panels are connected as a whole by pavement panel connectors. The design method for this pavement structure includes the following steps: S1. Obtain airport runway engineering design parameters, including aircraft type parameters and pavement geotechnical parameters: (1) Aircraft parameters: Based on the design requirements, determine the aircraft parameters that need to be designed for the airport to be built, including the static load of the main wheels, tire pressure, and tire contact area; (2) Conduct geotechnical tests on pavement geotechnical parameters. Subgrade geotechnical parameters include subgrade reaction modulus K and subgrade Poisson's ratio μt. Cement stabilized pavement geotechnical parameters include resilient modulus Ec, cement stabilized layer Poisson's ratio μc and thickness. S2. Preliminary design of precast pavement panels: Combining transportation and hoisting capacity, processing and manufacturing difficulty and cost, comprehensive performance parameters and indicators, comparative analysis is conducted to determine the size of precast pavement panels and preliminary arrangement of reinforcing bars. S3. Establish a finite element model of the pavement structure, including: (1) Based on the basic assumptions of small deflection elastic thin plate, the precast track panel element model is established using elastic plate elements; (2) A cement-stabilized layer model was established using solid elements; (3) A soil foundation model was established using discrete soil springs; (4) A finite element model of the pavement panel connector was established using an elastic-plastic rod system model; (5) Establish the edge constraints of the precast pavement panels, and the number of modeling panels is 4×3; S4. Calculation of internal forces in precast pavement panels to determine the maximum bending moment. M d,max That is, based on the finite element model of the pavement structure element established in step S3, different load combinations are considered, including design wheel load, fatigue effect, and fatigue effect plus temperature gradient, to obtain the maximum bending moment value under the corresponding load combination. M d,max =m×M d1 + M d2 In the formula, m is the condition coefficient. M d1 For the maximum design bending moment, M d2 The maximum temperature flexural moment; S5. Calculation of the bearing capacity of the precast pavement slab, and the maximum bending moment under the corresponding load combination obtained in step S4. M d,max According to the current GB50010 Code for Design of Concrete Structures, the reinforcement design of prestressed concrete slabs should be carried out, determining the type, quantity, and distribution of prestressing tendons and steel bars; when the requirements are not met... S d≤ R d or W max≤ W d If necessary, return to step S2 and redesign the reinforcement of the precast pavement panel, where, S d This is the design value for the bending moment. R d This is the design value for bending moment resistance. W max For the calculated value of the crack, W d Limits for cracks; S6. Optimization design of reinforcement of precast pavement panels: Based on influence surface analysis, the reinforcement of the edge area of ​​the precast pavement panels adopts a strengthened design, and the strengthened design area is determined by influence surface analysis. S7. Lifting condition calculation: On the precast pavement unit model established in step S4, the lifting stress level of the precast pavement is calculated according to the special tooling and lifting equipment. According to the current GB50666 Code for Construction of Concrete Structures, the gravity amplification factor during lifting is taken as 1.5. Its compressive stress is less than the standard value of concrete compressive strength, which meets the lifting requirements.

[0011] This invention establishes a complete and effective reinforcement design method for prefabricated pavement structures, effectively solving the reinforcement design problem of prefabricated reinforced concrete pavement structures in airports and providing a basis for studying the stress characteristics and laws of prefabricated pavement panels. It also considers the effects of temperature, foundation deformation, and fatigue effects, filling a gap in the industry. The design method is simple, versatile, and provides accurate calculation results. By combining finite element analysis with indoor and outdoor experiments, an analytical model that better reflects the actual stress state of pavement structures is established. The calculation process is concise and comprehensive, comprehensively considering the effects of temperature, self-weight, foundation deformation, and the interaction between adjacent slabs, thus truly reflecting the actual stress state of the pavement panel, with a deviation of approximately 10% compared to field tests. The adjacent precast pavement panels are connected by welding their connecting panels. In step S3, the finite element model of the precast pavement panel connecting panel adopts a spatial elastoplastic bar finite element model. The adjacent steel bars are rigidly connected to simulate welding. The material constitutive model is an ideal elastoplastic model, and translational constraints are applied to simulate the force and displacement curves of the long-side and short-side connecting panels of the precast pavement panels under ideal shear and tension / compression conditions in two directions, respectively. Multi-stage displacement loading is adopted, and the secant stiffness under 1 / 2 slab joint displacement is taken as the equivalent elastic stiffness of the welded connecting panel in three directions, including the vertical displacement stiffness, the extension displacement stiffness, and the tension / compression stiffness of the long-side and short-side connecting panels. A design method for precast pavement panel connecting panels is proposed. A three-dimensional finite element model considering contact is established using the finite element method. Combined with concrete pavement panel model tests with force transmission bars, the stress of the cement concrete panel at the joint, the shear stress of the force transmission bars, and the interface stress distribution law between the force transmission bars and the pavement panel are analyzed, providing a reference for the design and construction of force transmission bars at pavement panel joints.

[0012] When the precast pavement panel adopts prestressed reinforced concrete pavement panel, truss units are established on the corresponding nodes of the precast pavement panel unit model established in step S3 to simulate prestressed steel bars, and the prestress is applied by the cooling method; during the analysis process, a construction step is established, and the boundary conditions and load groups are gradually activated and deactivated to simulate the real boundary conditions of the pre-tensioned prestressed slab from processing to installation, and the impact of applying prestress on the precast pavement panel from processing to installation is analyzed.

[0013] In step S4, the maximum design bending moment M d1 To determine the impact surface, an influence surface calculation method is introduced. Bending moment distribution diagrams are drawn for the most unfavorable wheel load locations for various aircraft models in different directions. These diagrams are then superimposed to complete the influence surface analysis of the most unfavorable load. The load envelope diagram is used as the basis for design and reinforcement, yielding the maximum design bending moment. M d1 Introducing the influence surface calculation method can significantly reduce the overall reinforcement of the pavement slab. Different machine types play a controlling role in different layouts and along different slab edge directions, and the load on the same machine type varies significantly at different load distribution locations. Designing based on the maximum load on one side is clearly uneconomical. Using influence surface analysis can significantly reduce the overall reinforcement. The reinforcement in the pavement slab edge areas needs to be strengthened, and the areas requiring strengthened reinforcement are determined by influence surface analysis.

[0014] In step S4, the maximum temperature deflection moment M d2 The determination of the maximum temperature gradient is based on relevant specifications. The maximum temperature gradient is selected according to the natural zoning of highway cement concrete pavement. Based on the elastic half-space, the model is established by checking and correcting the assumptions of the Westercard method, and the temperature flexural stress is calculated to obtain the maximum temperature flexural moment. M d2 The specific conditions are as follows: (1) The precast pavement panels and the cement-stabilized layer are always in contact; (2) The temperature changes linearly along the surface of the precast track panel, and the temperature difference Δt is the same at all points in the panel; (3) The warping stress is caused by the constraint of the foundation reaction force under the slab; (4) The self-weight of the precast pavement panels is negligible.

[0015] The condition coefficients mentioned in step S3 m Determined by the following formula: m = W / W p In the formula, W To design the runway deflection during a single flight of the aircraft model, W p The runway deflection is the runway panel deflection of the same aircraft type after a certain number of design flights.

[0016] Example: This embodiment is a prestressed precast pavement structure, which is formed by assembling precast pavement panels 20 on a subgrade 10. The precast pavement panels 20 adopt a unidirectional prestressed reinforced concrete structure. Each precast pavement panel 20 has pavement panel connectors spaced apart along its width, and the pavement panel connectors of adjacent precast pavement panels 20 are welded together. A cement-stabilized layer is laid on the surface of the subgrade 10, which consists of a graded crushed stone cement-stabilized layer 11 and a filling layer 12. The pavement panel connectors include dowel bars 21 and tie bars 22. The dowel bars 21 include embedded L-shaped steel bars 31 set on the precast pavement panels 20 and anchoring steel bars 32 welded to 31. The welding between the embedded steel bars is full welding, forming a weld 33. The angle of the L-shaped embedded steel bars 31 should preferably be less than 90°. The tie bars 22 include embedded U-shaped steel bars 41 set on the precast pavement panels 20 and anchoring steel bars 32 welded to 41. The welding between the embedded steel bars is full welding, forming a weld 33.

[0017] The design methodology includes the following steps: S1. Obtain airport runway engineering design parameters, including aircraft type parameters and pavement geotechnical parameters: (1) Aircraft parameters: Based on the design requirements, determine the aircraft parameters that need to be designed for the airport to be built, including main wheel dynamic load, tire pressure and tire ground contact area.

[0018] This project uses a specific aircraft model as the design model, as this model has a highly representative load. The wheel imprint dimensions were calculated according to design specifications, with the wheel load being the dynamic load on one main wheel. The aircraft model parameters are: main landing gear configuration (SIN), tire pressure 1.53 MPa, main wheel dynamic load 196.52 kN, and tire contact area 1284.44 cm². 3 .

[0019] (2) Conduct geotechnical tests on pavement geotechnical parameters. Subgrade geotechnical parameters include subgrade reaction modulus K and subgrade Poisson's ratio μt. Cement stabilized pavement geotechnical parameters include resilient modulus Ec, cement stabilized layer Poisson's ratio μc and thickness.

[0020] S2. Preliminary design of precast pavement panels: Taking into account transportation and hoisting capabilities, manufacturing difficulty, and cost, the dimensions of the precast pavement panels and the preliminary arrangement of reinforcing bars are determined through comparative analysis. In this embodiment, the precast pavement panels are prestressed reinforced concrete pavement panels with a long side width a = 5m, a short side width b = 2.5m, and a thickness h = 0.2m. The material is C50 concrete with an elastic modulus of 35500MPa. The prestressing tendons are φ10 diameter stress-relieving steel wires (arranged vertically, with two wires at the same position), and the ultimate strength standard value f... ptk =1570MPa, the tension control stress coefficient is taken as 0.65, that is, about 80kN of prestress is applied.

[0021] S3. Establish a finite element model of the pavement structure elements (e.g., ... Figure 9 (as shown), including: (1) Based on the basic assumption of small deflection elastic thin plate, the prefabricated pavement panel element model is established by using elastic plate elements. Midas Civil is selected to carry out the numerical simulation of the system. Since the deformation of the airport prefabricated pavement panel is mainly bending deformation, the aircraft wheel mark size is large, and the loading form is uniformly distributed loading, plate elements are selected to simulate the airport prefabricated pavement panel.

[0022] (2) A cement-stabilized layer model is established using solid elements.

[0023] (3) A discrete soil spring model was established. A Winkler foundation model was established, and while establishing solid elements, a discrete spring was established to simulate the foundation action. The reaction modulus of the top surface of the base layer was taken as 90 MN / m. 3 .

[0024] (4) A finite element model of the pavement panel connectors was established using an elastic-plastic rod system model. Welded pavement panel connectors with different stress characteristics were set around the precast pavement panels. According to the stress and temperature deformation characteristics of the precast pavement panels, the force transmission rods were arranged on the short side of the precast pavement panels, and the tie rods were arranged on the long side of the precast pavement panels. An equivalent elastic connection was used in the overall model to simulate the interaction between the precast pavement panels.

[0025] (5) Establish edge constraints for the precast pavement panels, with a model of 4×3 panels. At the corresponding nodes of the precast pavement panel unit model, establish truss units to simulate prestressed steel reinforcement, applying prestress using a cooling method. During the analysis, establish construction steps, simulating the actual boundary conditions of the pre-tensioned prestressed slab from fabrication to installation by gradually activating and deactivating boundary conditions and load groups. Calculate the prestress loss according to the current GB50010 Code for Design of Concrete Structures, which is approximately 13%.

[0026] S4. Calculation of internal forces in precast pavement panels to determine the maximum bending moment. M d,max That is, based on the finite element model of the pavement structure element established in step S3, different load combinations are considered, including design wheel load, fatigue effect, and fatigue effect plus temperature gradient, to obtain the maximum bending moment value under the corresponding load combination. M d,max =m×M d1 + M d2 In the formula, m is the condition coefficient. M d1 For the maximum design bending moment, M d2 The maximum temperature flexural moment; Introducing the influence surface calculation method, bending moment distribution diagrams of the most unfavorable wheel load positions for different aircraft models are plotted in different directions. These bending moment distribution diagrams of different aircraft models and wheel load positions are then superimposed to complete the influence surface analysis of the most unfavorable load, yielding a load envelope diagram (e.g., ...). Figure 7 As shown); in this embodiment, the wheel tracks and landing gear arrangement of a certain aircraft model are as follows Figure 6a , Figure 6b and Figure 6c As shown, under three load distribution methods for a certain aircraft model's wheel load, the maximum positive bending moment in the long side direction is... M d,max =59.9 kN·m / m, maximum negative bending moment M d,max =-10.8kN.m / m; Maximum positive bending moment in the short side direction M d,max =47.5 kN·m / m, maximum negative bending moment M d,max =30.0kN.m / m, and the maximum misalignment of its corner, long side and short side occurs at the corner position, which is -2.056mm.

[0027] S5. Calculation of the bearing capacity of the precast pavement slab, and the maximum bending moment under the corresponding load combination obtained in step S3. M d,max According to the current GB50010 Code for Design of Concrete Structures, the reinforcement design of prestressed concrete slabs should be carried out, determining the type, quantity, and distribution of prestressing tendons and steel bars; when the requirements are not met... S d≤ R d or W max≤ W d If necessary, return to step S2 and redesign the reinforcement of the precast pavement panel, where, S d This is the design value for the bending moment. R d This is the design value for bending moment resistance. W max For the calculated value of the crack, W d The value is the limit for crack width. In this implementation, the reinforcement results in S4 were checked for bending of the cross section and crack width, and both met the requirements.

[0028] S6. Optimized reinforcement design of precast pavement panels: Based on influence surface analysis, the reinforcement of the edge areas of the precast pavement panels adopts a strengthened design. The strengthened design area is determined by influence surface analysis. Specific strengthened areas in this implementation are as follows: Figure 8 As shown.

[0029] Maximum positive bending moment along the longer side Md,max =60kN . m / m, maximum positive bending moment in the short side direction M d,max The reinforcement calculation was performed based on a value of 48 kN·m / m, and the reinforcement results are shown in Table 1 below.

[0030] Table 1. Reinforcement details per unit width in the short side direction Upper longitudinal rib 8 12 125 Lower longitudinal rib 8 12 125 stirrups 4 10 150 S7. Lifting Condition Calculation: On the precast pavement unit model established in step S3, the lifting stress level of the precast pavement is calculated according to the special lifting equipment. Based on the current GB50666 Code for Construction of Concrete Structures, the gravity amplification factor during lifting is taken as 1.5. The compressive stress is less than the standard value of concrete compressive strength, thus meeting the lifting requirements. In this implementation, under the four-point parallel lifting condition, after eliminating the stress concentration caused by the prestress at the slab end, the maximum tensile stress at the top and bottom of the slab is 0.5 MPa in the transverse direction (short side Y), while the longitudinal direction (long side X) maintains a full-section compression state. The compressive stress is less than the standard value of C50 concrete compressive strength, thus meeting the lifting requirements.

[0031] The above description is merely a preferred embodiment of the present invention. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A design method for an airport prefabricated reinforced concrete pavement structure, the pavement structure comprising, from bottom to top, a subgrade, a cement-stabilized layer, and a pavement layer, the pavement layer being formed by assembling precast pavement panels, the precast pavement panels being reinforced concrete pavement panels or prestressed reinforced concrete pavement panels, adjacent precast pavement panels being connected as a whole by pavement panel connectors, the design method for this pavement structure comprising the following steps: S1. Obtain airport runway engineering design parameters, including aircraft type parameters and pavement geotechnical parameters: (1) Aircraft parameters: Based on the design requirements, determine the aircraft parameters that need to be designed for the airport to be built, including the static load of the main wheels, tire pressure, and tire contact area; (2) Conduct geotechnical tests on pavement geotechnical parameters. Subgrade geotechnical parameters include subgrade reaction modulus K and subgrade Poisson's ratio μt. Cement stabilized pavement geotechnical parameters include resilient modulus Ec, cement stabilized layer Poisson's ratio μc and thickness. S2. Preliminary design of precast pavement panels: Combining transportation and hoisting capacity, processing and manufacturing difficulty and cost, comprehensive performance parameters and indicators, comparative analysis is conducted to determine the size of precast pavement panels and preliminary arrangement of reinforcing bars. S3. Establish a finite element model of the pavement structure, including: (1) Based on the basic assumptions of small deflection elastic thin plate, the precast track panel element model is established using elastic plate elements; (2) A cement-stabilized layer model was established using solid elements; (3) A soil foundation model was established using discrete soil springs; (4) A finite element model of the pavement panel connector was established using an elastic-plastic rod system model; (5) Establish the edge constraints of the precast pavement panels, and the number of modeling panels is 4×3; S4. Calculation of internal forces in precast pavement panels to determine the maximum bending moment. M d,max That is, based on the finite element model of the pavement structure element established in step S3, different load combinations are considered, including design wheel load, fatigue effect, and fatigue effect plus temperature gradient, to obtain the maximum bending moment value under the corresponding load combination. M d,max =m×M d1 + M d2 In the formula, m is the condition coefficient. M d1 For the maximum design bending moment, M d2 The maximum temperature flexural moment; S5. Calculation of the bearing capacity of the precast pavement slab, and the maximum bending moment value under the corresponding load combination obtained in step S4. M d,max The reinforcement design of the prestressed concrete slab should be carried out in accordance with the current GB50010 code for design of concrete structures, determining the type, quantity, and distribution of prestressing tendons and steel bars; when the requirements are not met... S d ≤R d or W max ≤W d If necessary, return to step S2 and redesign the reinforcement of the precast pavement panel, where, S d This is the design value for the bending moment. R d This is the design value for bending moment resistance. W max For the calculated value of the crack, W d Limits for cracks; S6. Optimization design of reinforcement of precast pavement panels: Based on influence surface analysis, the reinforcement of the edge area of ​​the precast pavement panels adopts a strengthened design, and the strengthened design area is determined by influence surface analysis. S7. Lifting condition calculation: On the precast pavement unit model established in step S4, the lifting stress level of the precast pavement is calculated according to the special tooling and lifting equipment. According to the current GB50666 Code for Construction of Concrete Structures, the gravity amplification factor during lifting is taken as 1.

5. Its compressive stress is less than the standard value of concrete compressive strength, which meets the lifting requirements.

2. The method for designing a structure of a prefabricated reinforced concrete pavement of an airport as claimed in claim 1, characterized in that: The adjacent precast pavement panels are connected by welding their connecting panels. In step S3, the finite element model of the precast pavement panel connecting panel adopts a spatial elastoplastic bar finite element model. The adjacent steel bars are connected by rigid connection to simulate welding. The material constitutive model is taken as an ideal elastoplastic model. Translational constraints are applied to simulate the force and displacement curves of the long side connecting panel and the short side connecting panel under ideal shear and tension / compression conditions in two directions. Multi-level displacement loading is adopted, and the secant stiffness under 1 / 2 plate joint displacement is taken as the equivalent elastic stiffness of the welded connecting panel in three directions, including the vertical displacement stiffness, the edge displacement stiffness, and the tension / compression stiffness of the long side connecting panel and the short side connecting panel.

3. The method for designing a structure of a prefabricated reinforced concrete pavement of an airport as claimed in claim 1, characterized in that: When the precast pavement panel adopts prestressed reinforced concrete pavement panel, truss units are established on the corresponding nodes of the precast pavement panel unit model established in step S3 to simulate prestressed steel bars, and the prestress is applied by the cooling method; during the analysis process, a construction step is established, and the boundary conditions and load groups are gradually activated and deactivated to simulate the real boundary conditions of the pre-tensioned prestressed slab from processing to installation, and the impact of applying prestress on the precast pavement panel from processing to installation is analyzed.

4. The method for designing a structure of a prefabricated reinforced concrete pavement of an airport as claimed in claim 1, wherein: In step S4, the maximum design bending moment M d1 To determine the impact surface, an influence surface calculation method is introduced. Bending moment distribution diagrams are drawn for the most unfavorable wheel load locations for various aircraft models in different directions. These diagrams are then superimposed to complete the influence surface analysis of the most unfavorable load. The load envelope diagram is used as the basis for design and reinforcement, yielding the maximum design bending moment. M d1 .

5. The design method for prefabricated reinforced concrete pavement structure of airports as described in claim 1, characterized in that: In step S4, the maximum temperature deflection moment M d2 The determination of the maximum temperature gradient is based on relevant specifications. The maximum temperature gradient is selected according to the natural zoning of highway cement concrete pavement. Based on the elastic half-space and Winkler foundation models, the model is established by checking and correcting the assumptions of the Westcard method. The temperature flexural stress is calculated to obtain the maximum temperature flexural moment. M d2 The specific conditions are as follows: (1) The precast pavement panels and the cement-stabilized layer are always in contact; (2) The temperature changes linearly along the surface of the precast track panel, and the temperature difference Δt is the same at all points in the panel; (3) The warping stress is caused by the constraint of the foundation reaction force under the slab; (4) The self-weight of the precast pavement panels is negligible.

6. The method for designing a precast reinforced concrete pavement structure of an airport as claimed in claim 1, wherein the step of The condition factor in S4 m is determined by calculation from the formula: m ＝ W ／ W p wherein W is the pavement panel deflection for a design model single flight, W p is the pavement panel deflection for the same model after the design number of flights.

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