Cold region airport rigid runway structure airworthiness performance prediction method

Abstract

The invention discloses a cold region airport rigid runway structure airworthiness performance prediction method. The method comprises the steps that the actual freezing depth of field channel soil is obtained; calculating the theoretical freezing depth of the field channel soil body according to the actually measured data; calculating the effective thickness of the airport pavement slab in the cold region; checking a standard load effect; calculating a working condition coefficient; calculating the deformation of the pavement slab under the load effect of the designed airplane; detecting the actual deformation of the cold region airfield runway pavement slab; calculating the airworthiness performance coefficient of the pavement structure; sending a pavement structure performance alarm signal to a user; and outputting a pavement airworthiness performance prediction report. According to the method, the specific climate conditions of the cold region and the actual response of the runway structure are comprehensively considered, the deformation of the runway structure is predicted in a mode of combining measured data and theoretical calculation, the airworthiness performance of the runway structure is evaluated accordingly, a customized prediction report can be provided according to user requirements, a scientific decision basis is provided for airport managers, and the economic benefit is improved. And the monitoring efficiency and the early warning accuracy of the airfield pavement deformation in the cold region are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of airport engineering, and in particular relates to a method for predicting the airworthiness performance of a rigid runway structure of an airport in cold regions. Background Art

[0002] At cold-region airports, the airworthiness of rigid runway structures is significantly affected by extreme climatic conditions, especially the effects of freeze-thaw cycles on runway structural performance. With seasonal temperature changes, soil freezing and thawing can cause significant deformation of the runway structure, which not only affects the safety of aircraft takeoff and landing, but may also cause early damage to the runway structure. Therefore, accurate prediction of the airworthiness of rigid runway structures at cold-region airports is crucial to ensuring flight safety and extending the service life of the runway.

[0003] Existing cold region airport runway airworthiness performance evaluation methods often rely on experience and qualitative judgment, lacking systematicity and precision. In addition, traditional evaluation methods usually do not consider the impact of ground temperature changes on runway structural performance, nor do they consider the unique climatic conditions in cold regions, such as the impact of air density changes on aircraft loads. Therefore, a more scientific and systematic method is needed to predict the airworthiness performance of rigid runway structures at cold region airports. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a method for predicting the airworthiness performance of a rigid runway structure at a cold region airport.

[0005] In order to achieve the above object, the method for predicting the airworthiness performance of a rigid runway structure of a cold region airport provided by the present invention comprises the following steps performed in sequence:

[0006] 1) System idle S1 stage: The system waits for user instructions. When the user issues an instruction to perform airworthiness performance prediction, it enters S2 stage;

[0007] 2) S2 stage of judging whether to make prediction: the system judges whether to make prediction of the airworthiness performance of the rigid runway structure of the cold region airport according to the user's instruction. If the judgment result is "yes", it enters S3 stage; otherwise, it returns to S1 stage;

[0008] 3) Collect ground temperature and air temperature data at cold-region airports to obtain the actual freezing depth of the runway soil in the S3 stage: use the ground temperature monitoring device buried in the soil foundation below the runway panel or in the soil around the runway to obtain the ground temperature data of different ground depths at multiple locations of the runway in winter; obtain the air temperature data from the data published by the meteorological bureau in the airport area or the data stored in the airport meteorological detection system; then obtain the actual freezing depth h of the runway soil based on the ground temperature data;

[0009] 4) S4 stage: Calculate the theoretical freezing depth of the runway soil based on the measured data: According to the test data of the cold region airport in each year, calculate the theoretical freezing depth of the runway soil in each year h t :

[0010]

[0011] Where: λ is the thermal conductivity of frozen soil; θ is the road surface temperature obtained according to the air temperature data obtained in step 3); τ is time; Q L is the phase change heat per unit soil volume; c is the volume heat capacity of the soil; α is the heat release coefficient of the soil surface; δ i is the thickness of the covering layer above the soil; i is the thermal conductivity of the overburden above the soil.

[0012] 5) Calculation of the effective thickness of the road panel at the cold region airport in the S5 stage: The effective thickness of the road panel h va The calculation formula is:

[0013] h va =μh re

[0014] Where: h re is the actual thickness of the road panel, which is between 25cm and 50cm in actual projects; μ is the effective thickness coefficient of the road panel, which is calculated by the following formula:

[0015] μ=h / h t

[0016] Where: h is the actual freezing depth of the field soil obtained in step 3); h t is the theoretical freezing depth of the field soil obtained in step 4);

[0017] 6) S6 stage of standard load verification considering the influence of air density in cold regions: According to the air density ρ of the area where the runway of the cold region airport is located obtained from actual testing d Loading action of standard model on pavement P d After correction, the corrected standard load action P va The formula is:

[0018]

[0019] Where: f The air density of the area where the airport is located in a non-cold region is obtained by actual detection. In the absence of actual detection values, the air density under standard conditions of 0°C and 1 standard atmospheric pressure is taken, and the value is 1.29Kg / m 3 ;

[0020] 7) S7 stage of calculating the operating coefficient based on the pavement structure parameters and pavement geometry parameters: The operating coefficient γ is calculated by the following formula:

[0021] γ=T 2 / k 2 -1

[0022] Where: k is the reaction modulus of the soil foundation, which can be obtained through geotechnical tests; T is the horizontal temperature force generated by the road panel under the action of temperature stress, which can be calculated by the following formula:

[0023] T=σ x bh re

[0024] Where: b is the width of the road panel, which can be 4.5m or 5m; h re is the thickness of the road panel; x is the horizontal temperature stress on the road panel during the cooling process, which is calculated by the following formula:

[0025]

[0026] Where: α v is the thermal expansion coefficient; E is the Young's modulus of the road panel; T v is the temperature difference between the road panel and the upper surface of the soil foundation; l re is the actual length of the road panel, which is 4.5m or 5.0m in actual projects; l va is the effective length of the road panel, which can be taken as 1.35 to 2.70 times the actual length of the road panel according to the joint conditions of the road surface. When the joints of the road panel without force transmission rods are completely cracked and only the aggregate bite force is used to transmit the load, it is taken as 1.35 to 1.60 times; when the joints of the road panel without force transmission rods are not completely cracked or the joints of the road panel with force transmission rods are completely cracked, it is taken as 1.60 to 2.00 times; when the joints of the road panel with force transmission rods are not completely cracked, it is taken as 2.00 to 2.70 times; the value of ζ is calculated by the following formula:

[0027]

[0028] Where: C x is the horizontal resistance coefficient of the foundation, which can be obtained through geotechnical tests;

[0029] 8) Stage S8 of judging whether the operating coefficient is equal to 0: judging whether the operating coefficient γ obtained in step 7) is equal to 0, if the operating coefficient γ is equal to 0, entering stage S10; if the operating coefficient γ is not equal to 0, entering stage S9;

[0030] 9) Stage S9 of judging whether the operating condition coefficient is greater than 0 and defining the operating condition type according to the operating condition coefficient: judging whether the operating condition coefficient γ obtained in step 7) is greater than 0, if the operating condition coefficient γ is greater than 0, entering stage S11; if the operating condition coefficient γ is less than 0, entering stage S12; then defining the case where the operating condition coefficient γ = 0 as operating condition 1, defining the case where the operating condition coefficient γ> 0 as operating condition 2, and defining the case where the operating condition coefficient γ< 0 as operating condition 3;

[0031] 10) Calculation of the pavement panel deformation under the design aircraft load in the first working condition S10 stage: According to the effective thickness h of the pavement panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 1 de , the formula is:

[0032]

[0033] Where: is the flexibility coefficient of the road panel; x is the distance from any point on the road panel to the midpoint of the road panel; is the section inertia moment of the road panel; C i are unknown coefficients, where i = 1, 2, 3, 4, and can be obtained by solving the following system of equations:

[0034]

[0035] Where: y l is the displacement at the midpoint of the road panel, and its value can be 0; θ 0 M is the rotation angle at the midpoint of the road panel, and its value can be 0; l is the bending moment at the midpoint of the road panel, and its value can be 0; Q 0 is the shear force at the midpoint of the road panel, and its value can be -P va / 2;

[0036] The maximum deformation of the road slab under the modified standard load is denoted as y demax ;

[0037] 11) Calculate the deformation of the road panel under the design aircraft load in the second working condition S11 stage: According to the effective thickness h of the road panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va, step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 2 de , the formula is:

[0038]

[0039] Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4:

[0040]

[0041] The maximum deformation of the road slab under the modified standard load is denoted as y demax ;

[0042] 12) Calculate the deformation of the road panel under the design aircraft load in the third working condition S12 stage: According to the effective thickness h of the road panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 3 de , the formula is:

[0043]

[0044] Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4:

[0045]

[0046] The maximum deformation of the road slab under the modified standard load is denoted as y demax ;

[0047] 13) Detecting the actual deformation of the runway panels at cold-region airports S13: arranging sensors on the runway panels to detect the maximum deformation y of the runway panels under the load of the aircraft each time during the takeoff process. rei , where i = 1, 2, 3, ...;

[0048] 14) Calculation of the airworthiness performance coefficient of the pavement structure in step S14: According to the maximum deformation of the pavement panel under the modified standard load obtained in step 10), step 11), or step 12), demax , the maximum deformation y of the road panel under the aircraft load obtained in step 13) reiAnd the aircraft traffic volume, calculate the airworthiness performance coefficient of the pavement structure:

[0049]

[0050] Where: N de is the cumulative design flight times of the runway. If this parameter is not available during the runway design and construction phase, it can be calculated using the following formula:

[0051] N de =S×q

[0052] Where: S is the design service life of the runway; q is the annual design aircraft traffic volume;

[0053] 15) Determine whether the pavement structure performance meets the airworthiness requirements in S15: According to the pavement structure airworthiness performance coefficient obtained in step 14) To determine whether the pavement structure performance meets the airworthiness requirements, if the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance meets the airworthiness requirements, and the process returns to S13. If the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance does not meet the airworthiness requirements and enters the S16 stage;

[0054] 16) S16 stage of sending a pavement structure performance warning signal to the user: the pavement structure airworthiness performance coefficient obtained in step 14) is converted to The specific value is sent to the user, warning the user that the pavement structure performance can no longer meet the airworthiness requirements and feeding back the position and historical deformation parameters of the pavement panel;

[0055] 17) Determine whether to end the pavement airworthiness performance prediction S17 stage: Determine whether to end the pavement airworthiness performance prediction according to the user demand instruction: If the judgment result is "yes", enter the S18 stage; otherwise return to the S13 stage;

[0056] 18) S18 stage of outputting pavement airworthiness performance prediction report: Outputting the pavement airworthiness performance prediction report of the entire prediction area, including whether the pavement area division meets the airworthiness requirements, the specific value of the airworthiness performance coefficient of each pavement panel, the historical deformation data of each pavement panel and the pavement panel structural performance parameters, thus completing the entire prediction process.

[0057] In step 3), the ground temperature monitoring device includes a ground temperature monitor and a temperature sensor.

[0058] In step 3), the method for obtaining the actual freezing depth of the tunnel soil is: drawing the winter tunnel geothermal distribution curve based on the acquired geothermal data. The winter tunnel geothermal distribution curve generally presents a gradual change from negative temperature to positive temperature with increasing stratum depth. The stratum depth corresponding to the 0°C critical point where negative temperature turns to positive temperature is the actual freezing depth h of the tunnel soil.

[0059] The method for predicting the airworthiness performance of the rigid runway structure of a cold-region airport provided by the present invention has the following beneficial effects: it can comprehensively consider the unique climate conditions in cold regions and the actual response of the runway structure, and predict the deformation of the runway structure by combining measured data with theoretical calculations, and evaluate the airworthiness performance of the runway structure accordingly. In addition, the method can not only provide customized prediction reports according to user needs and provide a scientific decision-making basis for airport managers, but also improve the monitoring efficiency and early warning accuracy of pavement deformation in cold-region airports, optimize maintenance strategies, reduce maintenance costs, and ultimately achieve safe and efficient operation of pavements in cold-region airports. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A flow chart of the method for predicting the airworthiness performance of a rigid runway structure at a cold region airport provided by the present invention. DETAILED DESCRIPTION

[0061] The present invention will be described in detail below with reference to the accompanying drawings.

[0062] like Figure 1 As shown, the method for predicting the airworthiness performance of the rigid runway structure of a cold region airport provided by the present invention comprises the following steps performed in sequence:

[0063] 1) System idle S1 stage: The system waits for user instructions. When the user issues an instruction to perform airworthiness performance prediction, it enters S2 stage;

[0064] 2) S2 stage of judging whether to make prediction: the system judges whether to make prediction of the airworthiness performance of the rigid runway structure of the cold region airport according to the user's instruction. If the judgment result is "yes", it enters S3 stage; otherwise, it returns to S1 stage;

[0065] 3) Collect ground temperature and air temperature data for cold-region airports to obtain the actual freezing depth of the runway soil in the S3 stage: use a ground temperature monitoring device buried in the soil foundation below the runway panel or in the soil around the runway to obtain ground temperature data at different stratum depths at multiple locations on the runway in winter; the ground temperature monitoring device includes a ground temperature monitor and a temperature sensor; the air temperature data is obtained from the data published by the meteorological bureau in the area where the airport is located or the data stored in the airport meteorological detection system; then the actual freezing depth h of the runway soil is obtained based on the ground temperature data, the method is: draw a winter runway ground temperature distribution curve based on the acquired ground temperature data, the winter runway ground temperature distribution curve generally presents a gradual change from negative temperature to positive temperature with increasing stratum depth, and the stratum depth corresponding to the critical point of 0°C where the negative temperature changes to the positive temperature is the actual freezing depth h of the runway soil.

[0066] 4) S4 stage: Calculate the theoretical freezing depth of the runway soil based on the measured data: According to the test data of the cold region airport in each year, calculate the theoretical freezing depth of the runway soil in each year h t :

[0067]

[0068] Where: λ is the thermal conductivity of frozen soil; θ is the road surface temperature obtained according to the air temperature data obtained in step 3); τ is time; Q L is the phase change heat per unit soil volume; c is the volume heat capacity of the soil; α is the heat release coefficient of the soil surface; δ i is the thickness of the covering layer above the soil; i is the thermal conductivity of the overburden above the soil.

[0069] 5) Calculation of the effective thickness of the pavement slab in cold regions in the S5 stage: Due to the difference in the ground temperature of the soil under the pavement slab, the strength and reaction modulus of the soil increase significantly after the soil freezes, resulting in a decrease in the pavement deformation under the aircraft load. However, the upper melted soil cannot be discharged in time, resulting in soil deterioration, which eventually increases the pavement deformation under the aircraft load. The difference in pavement deformation under the aircraft load before and after the soil freezes can be calculated by the effective thickness of the pavement slab h. va To quantify, the calculation formula is:

[0070] h va =μh re

[0071] Where: h re is the actual thickness of the road panel, which is generally between 25cm and 50cm in actual projects; μ is the effective thickness coefficient of the road panel, which is calculated by the following formula:

[0072] μ=h / h t

[0073] Where: h is the actual freezing depth of the field soil obtained in step 3); h t is the theoretical freezing depth of the field soil obtained in step 4);

[0074] 6) S6 stage of standard load verification considering the influence of air density in cold regions: Considering that the lift force on the aircraft during take-off and landing is proportional to the air density, the air density in cold regions is different from that in non-cold regions. The aircraft loads on the pavement of cold region airports under the same take-off and landing aircraft types are also different. Therefore, in order to obtain an aircraft load that is more suitable for the performance evaluation of the pavement of cold region airports, it is necessary to obtain the air density ρ of the area where the runway of the cold region airport is located based on the actual test. d Loading action of standard model on pavement P d After correction, the corrected standard load action P va The formula is:

[0075]

[0076] Where: f The air density of the area where the airport is located in a non-cold region is obtained by actual detection. In the absence of actual detection values, the air density under standard conditions of 0°C and 1 standard atmospheric pressure is taken, and the value is 1.29Kg / m 3 ;

[0077] 7) S7 stage of calculating the operating coefficient based on the pavement structure parameters and pavement geometry parameters: The operating coefficient γ is calculated by the following formula:

[0078] γ=T 2 / k 2 -1

[0079] Where: k is the reaction modulus of the soil foundation, which can be obtained through geotechnical tests; T is the horizontal temperature force generated by the road panel under the action of temperature stress, which can be calculated by the following formula:

[0080] T=σ x bh re

[0081] Where: b is the width of the road panel, usually 4.5m or 5m; h re is the thickness of the road panel; x is the horizontal temperature stress on the road panel during the cooling process, which is calculated by the following formula:

[0082]

[0083] Where: α v is the thermal expansion coefficient; E is the Young's modulus of the road panel; T v is the temperature difference between the road panel and the upper surface of the soil foundation; lre is the actual length of the road panel, which is 4.5m or 5.0m in actual projects; l va is the effective length of the road panel, which can be taken as 1.35 to 2.70 times the actual length of the road panel according to the joint conditions of the road surface. When the joints of the road panel without force transmission rods are completely cracked and only the aggregate bite force is used to transmit the load, it is taken as 1.35 to 1.60 times; when the joints of the road panel without force transmission rods are not completely cracked or the joints of the road panel with force transmission rods are completely cracked, it is taken as 1.60 to 2.00 times; when the joints of the road panel with force transmission rods are not completely cracked, it is taken as 2.00 to 2.70 times; the value of ζ is calculated by the following formula:

[0084]

[0085] Where: C x is the horizontal resistance coefficient of the foundation, which can be obtained through geotechnical tests;

[0086] 8) Stage S8 of judging whether the operating coefficient is equal to 0: judging whether the operating coefficient γ obtained in step 7) is equal to 0, if the operating coefficient γ is equal to 0, entering stage S10; if the operating coefficient γ is not equal to 0, entering stage S9;

[0087] 9) Stage S9 of judging whether the operating condition coefficient is greater than 0 and defining the operating condition type according to the operating condition coefficient: judging whether the operating condition coefficient γ obtained in step 7) is greater than 0, if the operating condition coefficient γ is greater than 0, entering stage S11; if the operating condition coefficient γ is less than 0, entering stage S12; then defining the case where the operating condition coefficient γ = 0 as operating condition 1, defining the case where the operating condition coefficient γ> 0 as operating condition 2, and defining the case where the operating condition coefficient γ< 0 as operating condition 3;

[0088] Under working condition 1, the horizontal temperature force T generated by the pavement slab under the action of temperature stress is equal to the reaction modulus k of the soil foundation. This working condition is only applicable to the special case where the horizontal temperature force T generated by the pavement slab under the action of temperature stress is close to the reaction modulus k of the soil foundation. Under working condition 2, the horizontal temperature force T generated by the pavement slab under the action of temperature stress is significantly greater than the reaction modulus k of the soil foundation. This working condition often occurs in the early stage of airport runway construction and use. During this period, the joints of the pavement slab are generally not cracked, the temperature difference between day and night in the airport runway environment is large, or the hydration reaction of the concrete pavement slab is more intense. Under working condition 3, the horizontal temperature force T generated by the pavement slab under the action of temperature stress is less than the reaction modulus k of the soil foundation. This working condition is applicable to the normal service stage of the airport runway. During this period, the joints of the pavement slab are generally completely cracked, the temperature change range of the airport runway environment is small, and the hydration heat of the concrete can be ignored.

[0089] 10) Calculation of the pavement panel deformation under the design aircraft load in the first working condition S10 stage: According to the effective thickness h of the pavement panel obtained in step 5) va, the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 1 de , the formula is:

[0090]

[0091] Where: is the flexibility coefficient of the road panel; x is the distance from any point on the road panel to the midpoint of the road panel; is the section inertia moment of the road panel; C i are unknown coefficients, where i = 1, 2, 3, 4, and can be obtained by solving the following system of equations:

[0092]

[0093] Where: y l is the displacement at the midpoint of the road panel, and its value can be 0; θ 0 M is the rotation angle at the midpoint of the road panel, and its value can be 0; l is the bending moment at the midpoint of the road panel, and its value can be 0; Q 0 is the shear force at the midpoint of the road panel, and its value can be -P va / 2;

[0094] The maximum deformation of the road slab under the modified standard load is denoted as y demax ;

[0095] 11) Calculate the deformation of the road panel under the design aircraft load in the second working condition S11 stage: According to the effective thickness h of the road panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 2 de , the formula is:

[0096]

[0097] Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4:

[0098]

[0099] The maximum deformation of the road slab under the modified standard load is denoted as y demax;

[0100] 12) Calculate the pavement deformation under the design aircraft load in the third working condition S12 stage: According to the effective thickness h of the pavement panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 3 de , the formula is:

[0101]

[0102] Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4:

[0103]

[0104] The maximum deformation of the road slab under the modified standard load is denoted as y demax ;

[0105] 13) Detecting the actual deformation of the runway panels at cold-region airports S13: arranging sensors on the runway panels to detect the maximum deformation y of the runway panels under the load of the aircraft each time during the takeoff process. rei , where i = 1, 2, 3, ...;

[0106] 14) Calculation of the airworthiness performance coefficient of the pavement structure in step S14: According to the maximum deformation of the pavement panel under the modified standard load obtained in step 10), step 11), or step 12), demax , the maximum deformation y of the road panel under the aircraft load obtained in step 13) rei And the aircraft traffic volume, calculate the airworthiness performance coefficient of the pavement structure:

[0107]

[0108] Where: N de is the cumulative design flight times of the runway. If this parameter is not available during the runway design and construction phase, it can be calculated using the following formula:

[0109] N de =S×q

[0110] Where: S is the design service life of the runway; q is the annual design aircraft traffic volume;

[0111] 15) Determine whether the pavement structure performance meets the airworthiness requirements in S15: According to the pavement structure airworthiness performance coefficient obtained in step 14) To determine whether the pavement structure performance meets the airworthiness requirements, if the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance meets the airworthiness requirements, and the process returns to S13. If the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance does not meet the airworthiness requirements and enters the S16 stage;

[0112] 16) S16 stage of sending a pavement structure performance warning signal to the user: the pavement structure airworthiness performance coefficient obtained in step 14) is converted to The specific value is sent to the user, warning the user that the pavement structure performance can no longer meet the airworthiness requirements and feeding back the position and historical deformation parameters of the pavement panel;

[0113] 17) Determine whether to end the pavement airworthiness performance prediction S17 stage: Determine whether to end the pavement airworthiness performance prediction according to the user demand instruction: If the judgment result is "yes", enter the S18 stage; otherwise return to the S13 stage;

[0114] 18) S18 stage of outputting pavement airworthiness performance prediction report: Outputting the pavement airworthiness performance prediction report of the entire prediction area, including whether the pavement area division meets the airworthiness requirements, the specific value of the airworthiness performance coefficient of each pavement panel, the historical deformation data of each pavement panel and the pavement panel structural performance parameters, thus completing the entire prediction process.

Claims

1. A method for predicting the airworthiness performance of a rigid runway structure at a cold region airport, characterized by: The method for predicting the airworthiness performance of a rigid runway structure at a cold region airport comprises the following steps performed in sequence: 1) System idle S1 stage: The system waits for user instructions. When the user issues an instruction to perform airworthiness performance prediction, it enters S2 stage; 2) S2 stage of judging whether to make prediction: the system judges whether to make prediction of the airworthiness performance of the rigid runway structure of the cold region airport according to the user's instruction. If the judgment result is "yes", it enters S3 stage; otherwise, it returns to S1 stage; 3) Collect ground temperature and air temperature data at cold-region airports to obtain the actual freezing depth of the runway soil in the S3 stage: use the ground temperature monitoring device buried in the soil foundation below the runway panel or in the soil around the runway to obtain the ground temperature data of different ground depths at multiple locations of the runway in winter; obtain the air temperature data from the data published by the meteorological bureau in the airport area or the data stored in the airport meteorological detection system; then obtain the actual freezing depth h of the runway soil based on the ground temperature data; 4) S4 stage: Calculate the theoretical freezing depth of the runway soil based on the measured data: According to the test data of the cold region airport in each year, calculate the theoretical freezing depth of the runway soil in each year h t : Where: λ is the thermal conductivity of frozen soil; θ is the road surface temperature obtained according to the air temperature data obtained in step 3); τ is time; Q L is the phase change heat per unit soil volume; c is the volume heat capacity of the soil; α is the heat release coefficient of the soil surface; δ i is the thickness of the covering layer above the soil; i is the thermal conductivity of the overburden above the soil; 5) Calculation of the effective thickness of the road panel at the cold region airport in the S5 stage: The effective thickness of the road panel h va The calculation formula is: h va =μh re Where: h re is the actual thickness of the road panel, which is between 25cm and 50cm in actual projects; μ is the effective thickness coefficient of the road panel, which is calculated by the following formula: μ=h / h t Where: h is the actual freezing depth of the field soil obtained in step 3); h t is the theoretical freezing depth of the field soil obtained in step 4); 6) S6 stage of standard load verification considering the influence of air density in cold regions: According to the air density ρ of the area where the runway of the cold region airport is located obtained from actual testing d Loading action of standard model on pavement P d After correction, the corrected standard load action P va The formula is: Where: f The air density of the area where the airport is located in a non-cold region is obtained by actual detection. In the absence of actual detection values, the air density under standard conditions of 0°C and 1 standard atmospheric pressure is taken, and the value is 1.29Kg / m 3 ; 7) S7 stage of calculating the operating coefficient based on the pavement structure parameters and pavement geometry parameters: The operating coefficient γ is calculated by the following formula: γ=T 2 / k 2 -1 Where: k is the reaction modulus of the soil foundation, which can be obtained through geotechnical tests; T is the horizontal temperature force generated by the road panel under the action of temperature stress, which can be calculated by the following formula: T=σ x b re Where: b is the width of the road panel, which can be 4.5m or 5m; h re is the thickness of the road panel; x is the horizontal temperature stress on the road panel during the cooling process, which is calculated by the following formula: Where: α v is the thermal expansion coefficient; E is the Young's modulus of the road panel; T v is the temperature difference between the road slab and the upper surface of the soil foundation; l re is the actual length of the road panel, which is 4.5m or 5.0m in actual projects; l va is the effective length of the road panel, which can be taken as 1.35 to 2.70 times the actual length of the road panel according to the joint conditions of the road surface. When the joints of the road panel without force transmission rods are completely cracked and only the aggregate bite force is used to transmit the load, it is taken as 1.35 to 1.60 times; when the joints of the road panel without force transmission rods are not completely cracked or the joints of the road panel with force transmission rods are completely cracked, it is taken as 1.60 to 2.00 times; when the joints of the road panel with force transmission rods are not completely cracked, it is taken as 2.00 to 2.70 times; the value of ζ is calculated by the following formula: Where: C x is the horizontal resistance coefficient of the foundation, which can be obtained through geotechnical tests; 8) Stage S8 of judging whether the operating coefficient is equal to 0: judging whether the operating coefficient γ obtained in step 7) is equal to 0, if the operating coefficient γ is equal to 0, entering stage S10; if the operating coefficient γ is not equal to 0, entering stage S9; 9) Stage S9 of judging whether the operating condition coefficient is greater than 0 and defining the operating condition type according to the operating condition coefficient: judging whether the operating condition coefficient γ obtained in step 7) is greater than 0, if the operating condition coefficient γ is greater than 0, entering stage S11; if the operating condition coefficient γ is less than 0, entering stage S12; then defining the case where the operating condition coefficient γ = 0 as operating condition 1, defining the case where the operating condition coefficient γ> 0 as operating condition 2, and defining the case where the operating condition coefficient γ< 0 as operating condition 3; 10) Calculation of the pavement panel deformation under the design aircraft load in the first working condition S10 stage: According to the effective thickness h of the pavement panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 1 de , the formula is: Where: is the flexibility coefficient of the road panel; x is the distance from any point on the road panel to the midpoint of the road panel; is the section inertia moment of the road panel; C i are unknown coefficients, where i = 1, 2, 3, 4, and can be obtained by solving the following system of equations: Where: y l is the displacement at the midpoint of the road panel, and its value can be 0; θ0 is the rotation angle at the midpoint of the road panel, and its value can be 0; M l is the bending moment at the midpoint of the road panel, and its value can be 0; Q0 is the shear force at the midpoint of the road panel, and its value can be -P va / 2; The maximum deformation of the road slab under the modified standard load is denoted as y demax ; 11) Calculate the deformation of the road panel under the design aircraft load in the second working condition S11 stage: According to the effective thickness h of the road panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 2 de , the formula is: Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4: The maximum deformation of the road slab under the modified standard load is denoted as y demax ; 12) Calculate the deformation of the road panel under the design aircraft load in the third working condition S12 stage: According to the effective thickness h of the road panel obtained in step 5) va , the corrected standard load action P obtained in step 6) va , step 7) obtains the horizontal temperature force T generated by the pavement panel under the action of temperature stress and the pavement structure parameters selected in the airport runway design stage, and calculates the deformation y of any point on the pavement panel under the modified standard load in working condition 3 de , the formula is: Undetermined coefficient C i It can be obtained by solving the following system of equations, where i = 1, 2, 3, 4: The maximum deformation of the road slab under the modified standard load is denoted as y demax ; 13) Detecting the actual deformation of the runway panels at cold-region airports S13: arranging sensors on the runway panels to detect the maximum deformation y of the runway panels under the load of the aircraft each time during the takeoff process. rei , where i = 1, 2, 3, ...; 14) Calculation of the airworthiness performance coefficient of the pavement structure in step S14: According to the maximum deformation of the pavement panel under the modified standard load obtained in step 10), step 11), or step 12), demax , the maximum deformation y of the road panel under the aircraft load obtained in step 13) rei And the aircraft traffic volume, calculate the airworthiness performance coefficient of the pavement structure: Where: N de is the cumulative design flight times of the runway. If this parameter is not available during the runway design and construction phase, it can be calculated using the following formula: Where: S is the design service life of the runway; q is the annual design aircraft traffic volume; 15) Determine whether the pavement structure performance meets the airworthiness requirements in S15: According to the pavement structure airworthiness performance coefficient obtained in step 14) To determine whether the pavement structure performance meets the airworthiness requirements, if the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance meets the airworthiness requirements, and the process returns to S13. If the pavement structure airworthiness performance coefficient It is judged that the pavement structure performance does not meet the airworthiness requirements and enters the S16 stage; 16) S16 stage of sending a pavement structure performance warning signal to the user: the pavement structure airworthiness performance coefficient obtained in step 14) is converted to The specific value is sent to the user, warning the user that the pavement structure performance can no longer meet the airworthiness requirements and feeding back the position and historical deformation parameters of the pavement panel; 17) Determine whether to end the pavement airworthiness performance prediction S17 stage: Determine whether to end the pavement airworthiness performance prediction according to the user demand instruction: If the judgment result is "yes", enter the S18 stage; otherwise, return to the S13 stage; 18) S18 stage of outputting pavement airworthiness performance prediction report: Outputting the pavement airworthiness performance prediction report of the entire prediction area, including whether the pavement area division meets the airworthiness requirements, the specific value of the airworthiness performance coefficient of each pavement panel, the historical deformation data of each pavement panel and the pavement panel structural performance parameters, thus completing the entire prediction process.

2. The method for predicting the airworthiness performance of a rigid runway structure at a cold region airport according to claim 1 is characterized by: In step 3), the ground temperature monitoring device includes a ground temperature monitor and a temperature sensor.

3. The method for predicting the airworthiness performance of a rigid runway structure at a cold region airport according to claim 1 is characterized by: In step 3), the method for obtaining the actual freezing depth of the tunnel soil is: drawing the winter tunnel geothermal distribution curve based on the acquired geothermal data. The winter tunnel geothermal distribution curve generally presents a gradual change from negative temperature to positive temperature with increasing stratum depth. The stratum depth corresponding to the 0°C critical point where negative temperature turns to positive temperature is the actual freezing depth h of the tunnel soil.

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