Airport rigid pavement PCR (Polymerase Chain Reaction) technology calculation method

Abstract

The invention relates to an airport rigid pavement PCR technology calculation method. The method comprises the following steps: S1, obtaining pavement structure parameters and aircraft traffic volume parameters of a rigid pavement; s2, calculating ACR, determining a model corresponding to the maximum ACR value and an operation state of the model, and taking the model as AM; s3, calculating accumulated action times and allowable action times of each machine type; s4, calculating a pavement fatigue accumulated damage factor and determining a key model; s5, calculating ACRG of the maximum allowable mass of the key model, and recording the ACRG as PCRi; s6, judging whether the key machine type is the machine type corresponding to the maximum ACR value in S2, if so, executing S7, otherwise, deleting the key machine type from the machine type combination to form a new machine type combination, and returning to S4; and S7, calculating the PCR value of the evaluation pavement based on the PCRi of the key model. Compared with the prior art, the method has the advantages of improving the PCR calculation accuracy of the rigid pavement of the airport and the like.

Description

Technical Field

[0001] The invention relates to the field of airport rigid pavement bearing capacity evaluation, and in particular to a PCR technical calculation method for airport rigid pavement. Background Art

[0002] The evaluation of the bearing capacity of airport pavement structures is of great significance to the safety of airport operations. Due to the repeated effects of aircraft loads and the influence of the external environment, the bearing capacity of the pavement structure decreases with the increase of service life. Therefore, it is necessary to regularly test and evaluate the bearing capacity of the airport pavement structure to ensure the safe operation of aircraft.

[0003] Currently, the ACN-PCN evaluation method is used. However, as the design method of rigid pavement has undergone major changes, the ACN-PCN technical evaluation method based on the inverse process of the traditional structural design method can no longer fully meet the requirements of the pavement structure bearing capacity evaluation, which is mainly manifested in the following points: 1) There is a big difference between the standard structure calculated by ACN and the current airport pavement structure; 2) PCN calculation mostly adopts the design model method, and the selection of design models lacks scientificity, and the PCN calculated by different design models is quite different; 3) The PCN calculation method is inconsistent with my country's current mechanical-empirical structural design method based on fatigue damage, and cannot truly reflect the airport pavement bearing capacity.

[0004] The airport pavement strength ACR-PCR evaluation method provides the calculation principle of pavement PCR, but lacks calculation methods and the accuracy of pavement strength evaluation is insufficient. Summary of the invention

[0005] The purpose of the present invention is to provide a technical calculation method for PCR of airport rigid pavement in order to improve the accuracy of PCR calculation of airport pavement.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] S1. Obtaining pavement structure parameters and aircraft traffic volume parameters of the rigid pavement;

[0008] S2, calculating the ACR of each aircraft type in the aircraft type combination in the aircraft traffic volume parameters and determining the aircraft type and its operating status corresponding to the maximum ACR value, and the aircraft type corresponding to the maximum value is recorded as AM;

[0009] S3, the cumulative number of actions of each model in the computer type combination N ij and the permissible number of actions N ei ;

[0010] S4, CDF of the maximum cumulative fatigue damage of pavement under computer-based combined action max , find the CDF of maxThe model with the greatest contribution is the key model and is recorded as AC i ;

[0011] S5. Adjust the CDF of key models to CDF max , then CDF max is the maximum fatigue cumulative damage factor generated by all aircraft types at the beginning, and the maximum cumulative number of actions of the key aircraft type is obtained according to the allowable number of actions of the key aircraft type. The maximum cumulative number of actions of the key aircraft type is kept unchanged, and the weight of the key aircraft type in the obtained combination is adjusted until the maximum fatigue cumulative damage factor generated by the key aircraft type on the pavement is 1. The maximum allowable mass of the key aircraft type at this time is obtained, and the ACR value ACR of the key aircraft type at the maximum allowable mass is calculated. G , recorded as PCR i ;

[0012] S6. Determine the key model AC i Is it the model AM corresponding to the maximum ACR value in S2? If so, execute S7. Otherwise, delete the key model from the model combination to form a new model combination, and return to S4.

[0013] S7, PCR based on key models i Calculate the PCR value of the evaluation pavement.

[0014] Furthermore, the cumulative number of actions N ij for:

[0015] N ij =N i ×P ij

[0016] Among them, P ij is the distribution probability of the lateral displacement of the main landing gear load of the specified aircraft type i on the pavement at strip j during the evaluation period, N i It indicates the number of times the aircraft type i operates on the rigid pavement of the airport to be evaluated.

[0017] Furthermore, the distribution probability of the lateral displacement of the main landing gear load of the specified aircraft type i on the pavement at strip j during the evaluation period is:

[0018]

[0019] in,

[0020] σ—standard deviation of the lateral offset distribution of the main landing gear wheel track of aircraft i;

[0021] D j —The distance between the center line of strip j and the road surface guide line;

[0022] —The distance between the centerline of the wheel k of the main landing gear of aircraft i and the centerline of the taxiing guide of the runway, k=1, 2, ..., K, where K is the number of parallel transverse wheels in the main landing gear configuration. The value of K is determined according to the number of parallel transverse wheels in the main landing gear configuration. The K value of a single-axle single-wheel is 1, and the K value of a single-axle double-wheel, double-axle double-wheel, and three-axle double-wheel is 2;

[0023] W—Main landing gear wheel footprint width.

[0024] Furthermore, the maximum cumulative fatigue damage CDF max for:

[0025] CDF max =Max(CDF j )

[0026] Among them, CDF j It represents the fatigue cumulative damage factor of the main landing gear of each model under the load at strip j.

[0027] Furthermore, the fatigue cumulative damage factor is:

[0028]

[0029] I is the number of aircraft types operating on the pavement during the evaluation period. Wherein, the fatigue cumulative damage factor of the pavement panel at strip j under the main landing gear load of the specified aircraft type i (i = 1, 2, ..., I); N ij N is the cumulative number of times the main landing gear load of the specified aircraft type i acts at strip j during the evaluation period; ei It is the permissible number of times the pavement is subjected to the main landing gear load of the specified aircraft type i during the evaluation period.

[0030] Furthermore, the PCR value is used to evaluate the airport pavement carrying capacity. When the aircraft's ACR does not exceed the PCR, the aircraft can operate on the pavement without restrictions;

[0031] When the aircraft's ACR exceeds the PCR but does not exceed 1.10 times the PCR, the aircraft may operate with restrictions, provided that the number of overload operations per year does not exceed 5% of the total number of operations per year;

[0032] When the aircraft's ACR exceeds 1.10 times the PCR, a special overload operation evaluation of the runway is required.

[0033] Furthermore, the aircraft traffic volume parameters include: evaluation period, aircraft type combination and number of operations of each aircraft type; the pavement structure parameters include the flexural strength, bending and tensile elastic modulus, thickness and Poisson's ratio of the cement concrete pavement surface layer of the pavement in the evaluation area, the rebound modulus, thickness, rebound modulus and Poisson's ratio of the base layer and cushion layer, and the reaction modulus of the top surface of the roadbed.

[0034] Furthermore, the evaluation period is the service life of the pavement that can meet the airworthiness requirements since its construction.

[0035] Furthermore, the method for collecting the flexural strength of the cement concrete pavement surface layer is:

[0036] When there are airport pavement design documents, the flexural strength of the cement concrete surface layer is the design flexural strength of the pavement surface layer in the evaluated area; when the design documents are missing, the flexural strength of the cement concrete surface layer is determined based on on-site core sample tests.

[0037] Furthermore, the method for collecting the operation times of each model is to determine it by using an estimation method based on historical operation data.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention calculates the PCR of asphalt overlaid composite pavement through the airport pavement structure parameters and the operating aircraft traffic volume parameters. The calculation process takes into account factors such as the pavement structure mechanical response, pavement damage, multi-wheel and multi-axis influence, and lateral deviation of the wheel track. The cumulative damage factor is used as the conceptual basis for determining and publishing PCR and pavement design, thereby improving the accuracy of PCR calculation for airport rigid pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flow chart of the present invention;

[0041] Figure 2 is the cumulative damage distribution curve of pavement fatigue of each aircraft type, where Figure 2 (a) is the fatigue cumulative damage distribution curve of all aircraft models. Figure 2 (b) is the fatigue cumulative damage distribution curve under the combined action of A321 and A320. Figure 2 (c) is the fatigue cumulative damage distribution curve under the action of A320 only DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0043] Glossary: ​​PCR (Pavement Classification Level) and ACR (Aircraft Classification Level).

[0044] The present invention proposes a PCR technology calculation method for airport rigid pavement. The flowchart of the method is as follows: Figure 1 As shown, the method comprises the following steps:

[0045] S1. Obtaining pavement structure parameters and aircraft traffic volume parameters;

[0046] S2, calculating the ACR of each aircraft type in the aircraft type combination in the aircraft traffic volume parameters and determining the aircraft type and its operating status corresponding to the maximum ACR value, and the aircraft type corresponding to the maximum value is recorded as AM;

[0047] S3, the cumulative number of actions of each model in the computer type combination N ij and the permissible number of actions N ei ;

[0048] S4. Calculate the maximum cumulative fatigue damage CDF of the aircraft type combination in the aircraft combined traffic volume max , find the CDF of max The model with the greatest contribution is the key model and is recorded as AC i ;

[0049] S5. Adjust the CDF of key models to CDF max (At this time, CDF max is the maximum fatigue cumulative damage factor generated by all aircraft types at the beginning) and the maximum cumulative number of actions of the key aircraft type is obtained according to the allowable number of actions of the key aircraft type. The maximum cumulative number of actions of the key aircraft type is kept unchanged, and the weight of the key aircraft type in the obtained combination is adjusted until the maximum fatigue cumulative damage factor generated by the key aircraft type on the pavement is 1. The maximum allowable mass of the key aircraft type at this time is obtained, and the ACR of the key aircraft type at the maximum allowable mass is calculated. G , recorded as PCR i ;

[0050] S6. Determine the key model (AC i ) is the model (AM) corresponding to the maximum ACR value in S2, if so, execute S7, otherwise delete the key model from the model combination, form a new model combination, and return to S4;

[0051] S7, PCR based on key models i Calculate the PCR value of the evaluation pavement.

[0052] The purpose of the present invention is to provide a method for calculating the PCR technology of an airport rigid pavement, which calculates the PCR of a rigid pavement by using the airport pavement structure parameters and the traffic volume parameters of operating aircraft, and realizes an accurate evaluation of the ACR-PCR bearing capacity of an airport rigid pavement. The specific steps of the present invention are:

[0053] S1: Determine the pavement structure parameters and aircraft traffic parameters. For existing rigid pavements, the pavement structure parameters and aircraft traffic parameters are determined through testing or investigation; for rigid pavements in the design stage, the pavement structure parameters and aircraft traffic parameters are taken according to the pavement design plan. The aircraft traffic parameters include: evaluation period, aircraft type combination and the number of operations of each aircraft type; the pavement structure parameters include the flexural strength, bending and tensile elastic modulus, thickness and Poisson's ratio of the cement concrete pavement surface layer of the pavement in the evaluation area, the rebound modulus, thickness, rebound modulus and Poisson's ratio of the base layer and cushion layer, and the reaction modulus of the top surface of the roadbed;

[0054] The data collection method of the flexural strength of the cement concrete surface layer is as follows:

[0055] When there are airport pavement design documents, the flexural strength of the cement concrete surface layer is the design flexural strength of the pavement surface layer in the evaluated area; when the design documents are missing, the flexural strength of the cement concrete surface layer is determined based on on-site core sample tests.

[0056] The method for collecting data on the thickness of each structural layer of the rigid pavement is as follows:

[0057] The thickness of the cement concrete surface layer can be determined based on the analysis of the project completion data; for airports where the completion data is lost or missing, data collection should be carried out by on-site coring or ground penetrating radar.

[0058] The data collection method of the flexural elastic modulus of the cement concrete surface layer, the rebound modulus of the base layer and the cushion layer, and the Poisson's ratio is as follows:

[0059] When there are airport pavement design documents, the flexural elastic modulus of the cement concrete surface layer and the rebound modulus of the base layer and cushion layer are the design values ​​of the evaluation area; when the design documents are missing, they can be determined by referring to the "Technical Specifications for Evaluation and Management of Civil Airport Pavement" (MH / T 5024) based on the modulus inversion method of deflection detection.

[0060] The method for collecting Poisson's ratio data of each structural layer of the rigid pavement is as follows:

[0061] The Poisson's ratio of each structural layer is determined by the value specified in the "Civil Airport Cement Concrete Pavement Design Code" (MH / T 5004).

[0062] The method for collecting the reaction modulus data of the roadbed top surface is as follows:

[0063] When there are airport pavement design documents, the top surface reaction modulus of the roadbed is the design value of the evaluated area; when the design documents are missing, it can be determined by referring to the "Technical Specifications for Evaluation and Management of Civil Airport Pavement" (MH / T 5024) based on the modulus inversion method of deflection detection.

[0064] The data collection method for the evaluation period is as follows:

[0065] For newly built airports, it should be consistent with the design reference period; for pavements that are already in operation, the evaluation period should be determined by the airport management agency, based on the expected usage time of the pavement in the area, and the evaluation period should not be less than 5 years.

[0066] The method for collecting the running data of the combination of the above-mentioned models and each model is as follows:

[0067] The combination of aircraft types and the number of operations of each type should be determined by estimation based on historical operation data. For historical operation data, the airport management agency should collect as long as possible historical data on flight takeoffs and landings. For airports with an operation time of more than 10 years, flight information should be collected for at least the past ten years.

[0068] The following method can be used to estimate the number of operations of each model during the evaluation period:

[0069] In the near future: Select no less than two of the trend extrapolation method, exponential smoothing method, market share method, regression analysis method, and BP neural network method for comprehensive forecasting and mutual calibration.

[0070] Long term: analogy analysis, Delphi method, comprehensive judgment method, etc.

[0071] New airports: road or rail transport diversion method, tourism-related analysis method, analogy analysis method, etc.

[0072] S2: The ACR of each aircraft type in the computer type combination is determined by linear interpolation based on the ACR values ​​of the maximum and minimum weights of various aircraft types on rigid pavement provided in the "Technical Standards for Civil Airport Airfields" (MH 5001). The aircraft types are sorted according to the size of the ACR values, and the aircraft type and its operating status corresponding to the maximum ACR value are identified. The aircraft type corresponding to the maximum value is recorded as AM.

[0073] S3: The cumulative number of actions of each model in the computer type combination N ij and the permissible number of actions N ei .

[0074] The cumulative number of times N that the main landing gear load of the specified aircraft type i acts on the pavement at strip j is ij The calculation method is as follows:

[0075] Strip division: The pavement within 10m on both sides of the taxiing or running centerline is divided into strips horizontally, and the strip width is 0.25m.

[0076] Cumulative number of actions during the evaluation period N ij Calculate according to the following formula:

[0077] Nij =N i ×P ij

[0078] Among them, P ij is the distribution probability of the lateral displacement of the main landing gear load of the specified aircraft type i on the pavement at strip j during the evaluation period, calculated according to the following formula:

[0079]

[0080] Where:

[0081] σ—standard deviation of the lateral offset distribution of the main landing gear wheel track of aircraft i, m;

[0082] D j —The distance between the center line of strip j and the road surface guide line, m;

[0083] —The distance (m) between the centerline of the main landing gear wheel k (k=1, 2, ..., K) of aircraft i and the centerline of the taxiing guide on the runway, where K is the number of parallel transverse wheels in the main landing gear configuration. The value of K is determined according to the number of parallel transverse wheels in the main landing gear configuration. The K value of a single-axle single-wheel is 1, and the K value of a single-axle double-wheel, double-axle double-wheel, or three-axle double-wheel is 2;

[0084] W—Main landing gear wheel footprint width, m.

[0085] The permissible number of actions N of the main landing gear load for the specified aircraft type i ei It is calculated using the fatigue equation specified in the Code for Design of Cement Concrete Pavement for Civil Airports (MH / T 5004).

[0086] The maximum principal stress of the bottom of the designated aircraft model i under the main landing gear load acting on the critical load position of the runway panel is calculated using the finite element method.

[0087] S4: Calculate CDF under combined aircraft traffic max , determine the key models.

[0088] The maximum cumulative fatigue damage of the airport pavement is calculated according to the following formula:

[0089] The maximum cumulative fatigue damage of the airport pavement is calculated according to the following formula:

[0090] CDF max =Max(CDF j )

[0091]

[0092] In the superposition process, the CDF is calculated separately according to the takeoff and landing of each aircraft type, and the original CDF of each aircraft type is split into takeoff and landing, which can be regarded as two types of takeoff and landing. j represents the fatigue cumulative damage factor of each aircraft type under the main landing gear load at strip j; I is the number of aircraft types running on the pavement during the evaluation period. Among them, the fatigue cumulative damage factor of the pavement panel at strip j under the main landing gear load of the specified aircraft type i (i=1,2,……,I) is calculated according to the following formula:

[0093]

[0094] Among them, N ij N is the cumulative number of times the main landing gear load of the specified aircraft type i acts at strip j during the evaluation period; ei The permissible number of pavement actions under the main landing gear load of the specified aircraft type i during the evaluation period.

[0095] Find the CDF of max The model with the greatest contribution is the key model and is recorded as AC i .

[0096] S5: Calculate PCR based on the determined key aircraft type and aircraft combination. Adjust the CDF generated by the key aircraft type to CDF max (At this time, CDF max is the maximum fatigue cumulative damage factor generated by all aircraft types at the beginning), and the maximum cumulative number of actions of the key aircraft type is calculated based on the allowable number of actions of the key aircraft type. Keep the calculated maximum cumulative number of actions of the key aircraft type unchanged, adjust the weight of the key aircraft type until the CDF value generated by the key aircraft type acting on the pavement is 1, record this weight, and interpolate the ACR of the key aircraft type at this weight according to the "Technical Standards for Civil Airport Airfields" (MH 5001), recorded as PCR i .

[0097] S6: If the key model (AC i ) is the model (AM) with the largest ACR value in the aircraft combination list, and jump to S7. If the key model is not the model with the largest ACR value in the aircraft combination list, then the key model is removed to form a new aircraft combination list, and S4-S5 are repeated until the key model is the model corresponding to the largest ACR value in the aircraft list;

[0098] S7: Calculate the PCR value of the evaluation surface, PCR = max PCR i , the final result needs to be rounded.

[0099] The final PCR is the pavement classification level, which is used to evaluate the airport pavement bearing capacity:

[0100] When the aircraft ACR does not exceed PCR, the aircraft can operate on the runway without restrictions;

[0101] When the aircraft ACR exceeds the PCR but does not exceed 1.10 times the PCR, the aircraft may operate with restrictions, provided that the number of overload operations per year does not exceed 5% of the total number of operations per year;

[0102] When the aircraft ACR exceeds 1.10 times the PCR, a special overload operation evaluation of the runway is required.

[0103] Compared with the prior art, the present invention has the following beneficial effects:

[0104] The ACR-PCR evaluation method unifies the pavement structure design and the pavement evaluation system. The present invention proposes a rigid pavement PCR technical calculation method based on the inverse process of pavement structure design for rigid pavements. The calculation process takes into account factors such as the pavement structure mechanical response, pavement damage, multi-wheel and multi-axis influence, and lateral wheel track deviation. The cumulative damage factor is used as the conceptual basis for determining and publishing PCR and pavement design, which solves the shortcomings of the previous ACN-PCN evaluation method. The evaluation results can more truly reflect the actual bearing capacity of the airport pavement.

[0105] During actual experiment, the steps of the present invention include:

[0106] S1: Obtain pavement structural parameters and aircraft traffic volume parameters. In this embodiment, the pavement to be evaluated is an existing cement concrete pavement. The pavement structure includes three layers: surface layer, upper base layer, and lower base layer. The pavement structural parameters are determined through field tests: the flexural tensile strength of cement concrete and the thickness of each structural layer are determined through field core sample tests; the modulus of each structural layer of the pavement and the roadbed reaction modulus are obtained by inverting the test data of bending and settlement tests; the Poisson's ratio data of each structural layer is determined by the values ​​specified in the "Civil Airport Cement Concrete Pavement Design Code" (MH / T 5004).

[0107] Evaluation period for testing airports p , evaluate the aircraft type and test the annual operation times N of each aircraft type in the airport i According to Articles 1 and 2 of D.0.6 of the Technical Specifications for Civil Airport Pavement Evaluation Management (MH / T 5024), it is determined as follows:

[0108] A1) The airport management agency or technical personnel determine the evaluation period according to the airport's use requirements. In this embodiment, the evaluation period is the service life of the pavement that can meet the airworthiness requirements since its construction.

[0109] A2) Determine the aircraft mix and annual flight times of the airport in the following way:

[0110] A21) Determine the aircraft type combination based on the actual operation of the airport, determine the annual average number of flights based on the airport's air traffic statistics for the past five years, and determine the annual number of flights of different aircraft types based on the annual average number of flights and the aircraft type combination.

[0111] A22) Determine the airport's aircraft mix and the annual operating numbers of different aircraft types based on the airport master plan document.

[0112] The parameters of each operating aircraft model at the inspection airport are obtained based on the "Civil Airport Cement Concrete Pavement Design Specifications" (MH / T5004).

[0113] S2: Based on the aircraft type combination determined in S1, according to the ACR values ​​of the maximum and minimum weights of various aircraft types on the rigid pavement provided in the "Technical Standards for Civil Airport Airfields" (MH 5001), linear interpolation is used to determine the ACR of each aircraft type, and the aircraft types are sorted according to the size of the ACR values. The aircraft type corresponding to the maximum ACR value and its take-off and landing operation status are clarified, and the aircraft type corresponding to the maximum value is recorded as AM.

[0114] S3: The allowable number of actions N of each machine type in the computer type combination ei The cumulative number of actions on each strip of the runway N ij .

[0115] S4: The permissible number of actions N calculated based on S3 ei And the cumulative number of actions N ij , calculate the cumulative damage of pavement fatigue under the combined aircraft traffic volume and determine the key aircraft models.

[0116] S5: Calculate PCR based on the determined key aircraft type and aircraft combination. Adjust the CDF generated by the key aircraft type to CDF max (At this time, CDF max is the maximum fatigue cumulative damage factor generated by all aircraft types at the beginning), and the maximum cumulative number of actions of the key aircraft type is calculated based on the allowable number of actions of the key aircraft type. Keep the calculated maximum cumulative number of actions of the key aircraft type unchanged, adjust the weight of the key aircraft type until the CDF value generated by the key aircraft type acting on the pavement is 1, record this weight, and interpolate the ACR of the key aircraft type at this weight according to the "Technical Standards for Civil Airport Airfields" (MH 5001), recorded as PCR i .

[0117] S6: If the key model (AC i) is the model (AM) with the largest ACR value in the aircraft combination list, then stop the calculation and proceed to S7. If the ACR of the key model is not the model corresponding to the largest ACR value in the aircraft combination list at this time, then remove the key model to form a new aircraft combination list, and repeat S4-S5 until the ACR of the key model is the model corresponding to the largest ACR value in the aircraft list, then stop the calculation and proceed to S7.

[0118] S7: Calculate the PCR value of the evaluation surface, PCR = max PCR i .

[0119] Specifically, the embodiment selects a runway equipped with parallel taxiways at a Class 4C airport in my country.

[0120] Through field test determination and design specification requirements, in this embodiment, the evaluation period is 30 years, the pavement panel bending tensile strength is 5.0MPa, and the pavement structure parameters and aircraft traffic volume parameters are shown in Table 1 and Table 2 respectively.

[0121] Table 1 Pavement structure parameters

[0122]

[0123]

[0124] Table 2 Aircraft traffic parameters

[0125] Model Name Maximum take-off mass (kg) Main landing gear load distribution factor Annual aircraft takeoffs B737-800 79004 0.95 1045 A321 83000 0.956 523 A320 76440 0.95 3658

[0126] According to the Technical Standards for Civil Airport Airfields (MH 5001), the ACR values ​​of the three aircraft types are interpolated. In this embodiment, the take-off ratio is 100%, so only the ACR values ​​of the three aircraft types in the take-off state are considered and sorted by size, as shown in Table 3.

[0127] Table 3 ACR values ​​of various models

[0128] Model Name A321 B737-800 A320 Corresponding ACR 537 528 476.8

[0129] Based on the runway pavement structure and aircraft parameters, the allowable number of actions for the three aircraft types is calculated according to the fatigue equation in the Civil Airport Cement Concrete Pavement Design Specification (MH / T5004). The calculation results are shown in Table 4:

[0130] Table 4 Allowable number of actions for each model

[0131] Model Name B737-800 A321 A320 Critical stress (MPa) 2.783 2.799 2.609 Allowable number of actions 28770 24040 156321

[0132] The cumulative damage distribution curves of pavement fatigue under the action of three types of aircraft were calculated and obtained. The results are shown in the attached figure. Figure 2As shown in (a), the key aircraft type in the current aircraft combination is B737-800, which is not the aircraft type corresponding to the maximum value in the ACR list. Therefore, B737-800 is eliminated. The cumulative damage distribution curve of pavement fatigue under the action of A321 and A320 is calculated and obtained. The results are shown in the attached figure. Figure 2 As shown in (b), the key aircraft model is A320; A320 is not the model corresponding to the maximum value in the ACR list, so A320 is eliminated; the pavement fatigue cumulative damage distribution curve under the action of A321 alone is calculated and obtained, and the results are shown in the attached figure. Figure 2 As shown in (c), A321 is the aircraft model corresponding to the maximum value in the ACR list, and the calculation ends.

[0133] By the attached Figure 2 (a) Obtain CDF max = 0.7001, according to the fatigue equation in the "Civil Airport Cement Concrete Pavement Design Specification" (MH / T5004) and the interpolation in the "Civil Airport Flight Area Technical Standard" (MH 5001), the maximum cumulative number of actions, maximum allowable mass, ACR of each aircraft type are calculated. i The calculation results are shown in Table 5.

[0134] Table 5 Calculation results list

[0135] Model Name B737-800 A321 A320 Maximum cumulative number of actions 19511 16831 109440 Maximum allowable mass (kg) 80620 84756 77850 <![CDATA[PCR i ]]> 521.76 537.32 489.41

[0136] PCR = max(PCR1, PCR2, PCR3) = 537.32, which is rounded to 540, so the PCR value of this runway is 540. The ACR values ​​of the above three aircraft types are all less than PCR, indicating that these three aircraft are not subject to weight restrictions on this runway.

[0137] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A PCR technical calculation method for airport rigid pavement, characterized in that: The method comprises the following steps: S1. Obtaining pavement structure parameters and aircraft traffic volume parameters of the rigid pavement; S2, calculating the ACR of each aircraft type in the aircraft type combination in the aircraft traffic volume parameters and determining the aircraft type and its operating status corresponding to the maximum ACR value, and the aircraft type corresponding to the maximum value is recorded as AM; S3, the cumulative number of actions of each model in the computer type combination N ij and the permissible number of actions N ei ; S4, CDF of the maximum cumulative fatigue damage of pavement under computer-based combined action max , find the CDF of max The model with the greatest contribution is the key model and is recorded as AC i ; S5. Adjust the CDF of key models to CDF max , then CDF max is the maximum fatigue cumulative damage factor generated by all aircraft types at the beginning, and the maximum cumulative number of actions of the key aircraft type is obtained according to the allowable number of actions of the key aircraft type. The maximum cumulative number of actions of the key aircraft type is kept unchanged, and the weight of the key aircraft type in the obtained combination is adjusted until the maximum fatigue cumulative damage factor generated by the key aircraft type on the pavement is 1. The maximum allowable mass of the key aircraft type at this time is obtained, and the ACR value ACR of the key aircraft type at the maximum allowable mass is calculated. G , recorded as PCR i ; S6. Determine the key model AC i Is it the model AM corresponding to the maximum ACR value in S2? If so, execute S7. Otherwise, delete the key model from the model combination to form a new model combination, and return to S4. S7, PCR based on key models i Calculate the PCR value of the evaluation pavement.

2. According to claim 1, a method for high-precision ship identification based on target detection and text recognition is characterized in that: Cumulative number of actions N ij for: N ij =N i ×P ij Among them, P ij is the distribution probability of the lateral displacement of the main landing gear load of the specified aircraft type i on the pavement at strip j during the evaluation period, N i It indicates the number of times the aircraft type i operates on the rigid pavement of the airport to be evaluated.

3. According to claim 2, a high-precision ship identification method based on target detection and text recognition is characterized in that: The distribution probability of the lateral displacement of the main landing gear load of a specified aircraft type i on the pavement at strip j during the evaluation period is: in, σ—standard deviation of the lateral offset distribution of the main landing gear wheel track of aircraft i; D j —The distance between the center line of strip j and the road surface guide line; —The distance between the centerline of the wheel k of the main landing gear of aircraft i and the centerline of the taxiing guide of the runway, k=1, 2, ..., K, where K is the number of parallel transverse wheels in the main landing gear configuration. The value of K is determined according to the number of parallel transverse wheels in the main landing gear configuration. The K value of a single-axle single-wheel is 1, and the K value of a single-axle double-wheel, double-axle double-wheel, and three-axle double-wheel is 2; W—Main landing gear wheel footprint width.

4. According to claim 1, a method for high-precision ship identification based on target detection and text recognition is characterized in that: Maximum cumulative fatigue damage CDF max for: CDF max =Max(CDF j ) Among them, CDF j It represents the fatigue cumulative damage factor of the main landing gear of each model under the load at strip j.

5. A high-precision ship identification method based on target detection and text recognition according to claim 4, characterized in that: The fatigue cumulative damage factor is: Among them, CDF ij is the fatigue cumulative damage factor of the pavement at strip j under the main landing gear load of the specified aircraft type i (i = 1, 2, ..., I) during the evaluation period; I is the number of aircraft types operating on the pavement during the evaluation period; N ij N is the cumulative number of times the main landing gear load of the specified aircraft type i acts at strip j during the evaluation period; ei The permissible number of pavement actions under the main landing gear load of the specified aircraft type i during the evaluation period.

6. The method for high-precision ship identification based on target detection and text recognition according to claim 1 is characterized in that: The PCR value is used to evaluate the airport pavement carrying capacity. When the aircraft's ACR does not exceed the PCR, the aircraft can operate on the pavement without restrictions. When the ACR of an aircraft exceeds the PCR but does not exceed 1.10 times the PCR, the aircraft may operate with restrictions, provided that the number of overload operations per year does not exceed 5% of the total number of operations per year; When the aircraft's ACR exceeds 1.10 times the PCR, a special overload operation evaluation of the runway is required.

7. The method for high-precision ship identification based on target detection and text recognition according to claim 1 is characterized in that: The aircraft traffic volume parameters include: evaluation period, aircraft type combination and the number of operations of each aircraft type; the pavement structure parameters include the flexural strength, bending and tensile elastic modulus, thickness and Poisson's ratio of the cement concrete pavement surface layer of the pavement in the evaluation area, the rebound modulus, thickness, rebound modulus and Poisson's ratio of the base layer and cushion layer, and the reaction modulus of the top surface of the roadbed.

8. A high-precision ship identification method based on target detection and text recognition according to claim 7, characterized in that: The evaluation period is the number of years of service that the pavement can meet the airworthiness requirements since its construction.

9. A method for high-precision ship identification based on target detection and text recognition according to claim 8, characterized in that: The method for collecting the flexural strength of the cement concrete pavement surface layer is: When there are airport pavement design documents, the flexural strength of the cement concrete surface layer is the design flexural strength of the pavement surface layer in the evaluated area; when the design documents are missing, the flexural strength of the cement concrete surface layer is determined based on on-site core sample tests.

10. A method for high-precision ship identification based on target detection and text recognition according to claim 9, characterized in that: The method for collecting the operating times of each model is to use an estimation method based on historical operating data.

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