An online evaluation method for load transfer capacity of airport rigid pavement joints

Abstract

The present invention relates to an online evaluation method for load transfer capacity of airport rigid pavement joints, comprising: arranging accelerometers; fixing the accelerometers on the plate edges of cement concrete plates of airport rigid pavement; demodulating the measurement data of two accelerometers of adjacent plates on both sides of the joint based on a fiber grating demodulator to obtain plate edge vibration displacement data under dynamic load; calculating the maximum values ​​of left plate vibration displacement and right plate vibration displacement based on the plate edge vibration displacement data, and after screening the plate edge vibration displacement data, matching them according to spatial position and time window, recording aircraft passing events; deleting all data corresponding to unpaired aircraft passing events; calculating the joint deflection load transfer capacity in real time based on the retained data; and evaluating the capacity level of the joint deflection load transfer capacity based on the evaluation criteria. Compared with the prior art, the present invention has the advantages of high evaluation accuracy and good real-time performance.

Description

Technical Field

[0001] The invention relates to the field of airport pavement engineering, and in particular to an online evaluation method for load transfer capacity of airport rigid pavement joints. Background Art

[0002] The joint is a relatively weak part of the airport cement concrete pavement. The load transfer capacity of the joint is of great significance for the pavement structure design, structural performance evaluation and joint disease prevention. The traditional evaluation of the joint load transfer capacity is to use HWD equipment to detect the deflection of the adjacent plate. The specification requires a detection frequency of 5 years. The low frequency makes it impossible for airport personnel to grasp the joint load transfer capacity in time, which makes it difficult to formulate a scientific and reasonable annual maintenance plan. Summary of the invention

[0003] The purpose of the present invention is to provide an online evaluation method for the load transfer capacity of airport rigid pavement joints, to improve the real-time and accuracy of the joint load transfer capacity evaluation, and to solve the problem that the airport personnel cannot grasp the joint load transfer capacity in time due to the low bending sinking frequency.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] An online evaluation method for load transfer capacity of airport rigid pavement joints comprises the following steps:

[0006] S1. Arrange accelerometers;

[0007] S2, fix the accelerometer on the edge of the cement concrete slab of the airport rigid pavement;

[0008] S3, demodulating the measurement data of two accelerometers of the adjacent plates on both sides of the joint based on the fiber Bragg grating demodulator to obtain the vibration displacement data of the plate edge under the dynamic load;

[0009] S4. Calculate the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data, filter the panel edge vibration displacement data, match the filtered data according to the spatial position and time window, and record the aircraft passing event;

[0010] S5. Delete all data corresponding to the unpaired aircraft passing events and retain the complete data pairs of the aircraft passing events;

[0011] S6. Real-time calculation of the joint deflection load transfer capacity based on the retained data;

[0012] S7. Evaluate the capacity level of the joint deflection load transfer capacity based on the evaluation criteria.

[0013] The longitudinal arrangement position of the accelerometer meets two conditions: the accelerometer is not exposed on the pavement surface and can sense the vibration of the concrete slab.

[0014] The accelerometer is arranged at a position 2 cm away from the top surface.

[0015] On the plane, the accelerometers are located on the main wheel tracks of the representative aircraft type, and the dynamic response of the accelerometers is stimulated when the aircraft dynamic load passes by.

[0016] The accelerometer is fixed in the form of a steel bar bracket.

[0017] Demodulating the measurement data of two accelerometers of adjacent plates at both sides of the joint based on the fiber grating demodulator specifically includes performing two integration processes on the measurement data of the accelerometers.

[0018] The method of calculating the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data is specifically as follows: finding the maximum vibration displacement max(l1) of the left side panel of the joint, recording the corresponding moment t1, at which time the vibration displacement of the right side panel of the joint is l2(t1); after a short moment Δt, the aircraft tire moves from the left panel to the right panel, and the vibration displacement of the right panel will reach the maximum value max(l2), recording the corresponding moment t2, t2=t1+Δt, at which time the vibration displacement of the left side panel of the joint is l1(t2).

[0019] Determine whether the maximum vibration displacement of the left plate and the maximum vibration displacement of the right plate satisfy max(l)>l t If it is satisfied, it is retained, otherwise it is deleted, and the screening of plate edge vibration displacement data is completed, where l t is the preconfigured displacement threshold.

[0020] When the short-term moment Δt=t2-t1<0.5s is satisfied, it is recorded as an aircraft passing event.

[0021] The joint deflection load transfer capacity LTE δ The calculation method is:

[0022]

[0023] Among them, LTE δ1 The load capacity of the left panel, LTE δ2 is the load transfer capacity of the right panel.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention can timely and accurately sense the vibration of the concrete slab by reasonably arranging accelerometers, and realize real-time vibration signal analysis by using a fiber optic Bragg grating demodulator, so as to calculate the load transfer capacity of the joint deflection in real time and evaluate its capacity level, thereby solving the problem in the prior art that the low bending frequency causes the airport personnel to be unable to timely grasp the load transfer capacity of the joint, greatly improving the monitoring frequency, making it possible to discover the decline in the service performance of the structure earlier, and helping the maintenance department to timely grasp the joint performance and scientifically and reasonably formulate an annual maintenance plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the method of the present invention;

[0027] Figure 2 The schematic diagram of the mechanical response of the pavement structure when the wheel load acts on the edge of the joint;

[0028] Figure 3 It is a schematic diagram of the layout position of the accelerometer on the cross section;

[0029] Figure 4 This is a schematic diagram of sensor fixing;

[0030] Figure 5 Schematic diagram of the method for determining the calculation parameters of the joint deflection load transfer capacity. DETAILED DESCRIPTION

[0031] 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.

[0032] This embodiment provides an online evaluation method for the load transfer capacity of airport rigid pavement joints. Figure 1 As shown, the following steps are included:

[0033] S1. Lay out accelerometers.

[0034] The schematic diagram of the mechanical response of the pavement structure when the wheel load acts on the edge of the joint is shown in Figure 2 shown.

[0035] To ensure that the accelerometer can sense the vibration of the concrete slab under the dynamic load of the aircraft, and also to ensure that the accelerometer is not exposed on the pavement surface, the accelerometer is placed 2 cm away from the top surface.

[0036] On the plane, collect the flight data of the current newly built airport, consider the aircraft models used on the expected routes, and arrange the accelerometers near the main wheel tracks of the representative aircraft models according to the main landing gear wheel tracks of the main aircraft models. Make the accelerometers located on the main wheel tracks of the representative aircraft models, and stimulate the dynamic response of the accelerometers when the dynamic load of the aircraft passes by.

[0037] Table 1 shows the main landing gear track widths of common aircraft models.

[0038] Table 1 Main landing gear track widths of common aircraft models

[0039]

[0040]

[0041] In this embodiment, an accelerometer is to be buried in the runway of an international airport flight area. In the early stage, based on the flight data of the newly built airport, it is considered that the aircraft type used in the route is mainly A320, and the size of the rigid runway panel is 5m*5m*0.4m. The accelerometer is arranged on the plane at a distance of 4.475m from the center line of the wheel track, that is, 52.5cm from the edge of the panel. When the dynamic load of the aircraft passes by, the dynamic response of the accelerometer can be stimulated, such as Figure 3 shown.

[0042] S2. Fix the accelerometer to the edge of the cement concrete slab of the airport rigid pavement in the form of a steel support, such as Figure 4 shown.

[0043] S3. The measurement data of the two accelerometers of the adjacent plates on both sides of the joint are demodulated based on the fiber Bragg grating demodulator. The specific demodulation method is to integrate the measurement data of the accelerometer twice to obtain the vibration displacement data of the plate edge under the dynamic load, and there is no delay.

[0044] The technical parameters of the accelerometer are shown in Table 2.

[0045] Table 2 Accelerometer technical parameters

[0046] Technical indicators parameter Range ±10g Resolution 100ug Frequency response range 0.5~400Hz Normal working temperature -45～80℃ Transmission distance ≧5km Dimensions ≤25mm×25mm×40mm

[0047] In the demodulator, the signals collected by the accelerometer are stored at 60s intervals and the acceleration data is integrated twice to obtain the vibration displacement of the plate, that is, the vibration displacement-time curve on both sides of the joint:

[0048]

[0049] Where:

[0050] t0——starting time of excitation signal;

[0051] a(t)——the acceleration value of the sensor at time t;

[0052] Δa(t) is the acceleration error term of the sensor at time t, which is a linear function, that is, Δa(t) = k1t + k0, where k1 and k0 are determined by the following formula:

[0053]

[0054] Where:

[0055] t e ——The moment when the excitation signal ends.

[0056] S4. Calculate the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data, filter the panel edge vibration displacement data, match the filtered data according to the spatial position and time window, and record the aircraft passing event.

[0057] S5. Delete the data corresponding to all unpaired aircraft passing events and retain the complete data pairs of the aircraft passing events.

[0058] The calculation of the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data is specifically as follows: find the maximum vibration displacement max(l1) of the left side panel of the joint, record the corresponding time t1, at which time the vibration displacement of the right side panel of the joint is l2(t1); after a short moment Δt, the aircraft tire moves from the left panel to the right panel, and the vibration displacement of the right panel will reach the maximum value max(l2), record the corresponding time t2, t2=t1+Δt, at which time the vibration displacement of the left side panel of the joint is l1(t2), as shown in FIG. Figure 5 shown.

[0059] Determine whether the maximum vibration displacement of the left plate and the maximum vibration displacement of the right plate satisfy max(l)>l t If it is satisfied, it is retained, otherwise it is deleted, and the screening of plate edge vibration displacement data is completed, where l t is the preconfigured displacement threshold.

[0060] When the short-term moment Δt=t2-t1<0.5s is satisfied, it is recorded as an aircraft passing event.

[0061] S6. Calculate the joint deflection load transfer capacity in real time based on the retained data.

[0062] The joint deflection load transfer capacity LTE δ The calculation method is:

[0063]

[0064] Among them, LTE δ1 The load capacity of the left panel, LTE δ2 is the load transfer capacity of the right panel.

[0065] S7. Evaluate the capacity level of the joint deflection load transfer capacity based on the evaluation criteria.

[0066] In this embodiment, the evaluation criteria are set as shown in Table 3 in accordance with MH / T 5024-2019 Technical Specifications for Civil Airport Pavement Evaluation Management.

[0067] Table 3 Evaluation criteria for joint load transfer capacity

[0068] Rating good middle Second-rate Difference <![CDATA[LTE δ (%)]]> >80 80～56 55～31 <31

[0069] The capacity level of the joint deflection load transfer capacity can be determined based on the joint deflection load transfer capacity calculated in step S6 and Table 3.

[0070] 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. An online evaluation method for load transfer capacity of airport rigid pavement joints, characterized in that: The following steps are involved: S1. Arrange accelerometers; S2, fix the accelerometer on the edge of the cement concrete slab of the airport rigid pavement; S3, demodulating the measurement data of two accelerometers of the adjacent plates on both sides of the joint based on the fiber Bragg grating demodulator to obtain the vibration displacement data of the plate edge under the dynamic load; S4. Calculate the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data, filter the panel edge vibration displacement data, match the filtered data according to the spatial position and time window, and record the aircraft passing event; S5. Delete all data corresponding to the unpaired aircraft passing events and retain the complete data pairs of the aircraft passing events; S6. Real-time calculation of the joint deflection load transfer capacity based on the retained data; S7. Evaluate the capacity level of the joint deflection load transfer capacity based on the evaluation criteria; Demodulating the measurement data of two accelerometers of adjacent plates on both sides of the joint based on the fiber Bragg grating demodulator specifically includes performing two integration processes on the measurement data of the accelerometers; The calculation of the maximum vibration displacement of the left panel and the maximum vibration displacement of the right panel based on the panel edge vibration displacement data is specifically as follows: finding the maximum vibration displacement max(l1) of the left side panel of the joint, recording the corresponding time t1, at which time the vibration displacement of the right side panel of the joint is l2(t1); after a short moment Δt, the aircraft tire moves from the left panel to the right panel, and the vibration displacement of the right panel will reach the maximum value max(l2), recording the corresponding time t2, t2=t1+Δt, at which time the vibration displacement of the left side panel of the joint is l1(t2); Determine whether the maximum vibration displacement of the left plate and the maximum vibration displacement of the right plate satisfy max(l)>l t If it is satisfied, it is retained, otherwise it is deleted, and the screening of plate edge vibration displacement data is completed, where l t is a preconfigured displacement threshold; When the short-term moment Δt=t2-t1<0.5s is satisfied, it is recorded as an aircraft passing event; The joint deflection load transfer capacity LTE δ The calculation method is: Among them, LTE δ1 The load capacity of the left panel, LTE δ2 is the load transfer capacity of the right panel.

2. The method for online evaluation of load transfer capacity of airport rigid pavement joints according to claim 1 is characterized in that: The longitudinal arrangement position of the accelerometer meets two conditions: the accelerometer is not exposed on the pavement surface and can sense the vibration of the concrete slab.

3. The method for online evaluation of load transfer capacity of airport rigid pavement joints according to claim 2 is characterized in that: The accelerometer is arranged at a position 2 cm away from the top surface.

4. The method for online evaluation of load transfer capacity of airport rigid pavement joints according to claim 2 is characterized in that: On the plane, the accelerometers are located on the main wheel tracks of the representative aircraft type, and the dynamic response of the accelerometers is stimulated when the aircraft dynamic load passes by.

5. The method for online evaluation of load transfer capacity of airport rigid pavement joints according to claim 1 is characterized in that: The accelerometer is fixed in the form of a steel bar bracket.

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