Train-induced vibration segregation test method and device for bridge asphalt pavement

Abstract

The present invention proposes a method and device for testing the vibration segregation of asphalt pavement on a bridge deck caused by a train. First, historical data on the vibration of the asphalt pavement on a highway bridge caused by a railway train in a specific scenario is obtained. Then, based on the vibration data, the typical vibration conditions of the test target are determined, wherein the typical vibration conditions include vibration amplitude, vibration frequency and duration, and the vibration simulation model is established. Then, according to the vibration simulation model and the equivalent conversion formula, the vibration test device is adaptively set to ensure the stable driving performance of the device. Finally, different target specimens are selected for simulation testing in conjunction with the test in the test scenario. The present invention can effectively simulate the vibration segregation conditions of asphalt pavement on a highway bridge caused by a railway train, taking into account the test temperature and vibration stability during the vibration of the asphalt pavement on the bridge deck, and overcomes the problem that the existing related vibration methods and devices are difficult to effectively and stably simulate the vibration segregation conditions of asphalt pavement on a bridge deck caused by a train.

Description

Technical Field

[0001] The present invention belongs to the field of bridge deck pavement vibration simulation, and in particular relates to a train-induced vibration segregation testing method and device for bridge deck asphalt pavement. Background Art

[0002] Bridge deck pavements are often constructed using asphalt mixtures. During construction, these materials have yet to develop sufficient strength and are highly susceptible to external vibrations, leading to segregation, which reduces construction quality and impacts service performance. This phenomenon is particularly pronounced in the renovation of road-rail bridge decks. Compared to highway bridges, these bridges are subject not only to the jolting vibrations of overhead highway vehicles but also to the vibrations of railway trains below. However, these two vibration effects are not uniform. In analyzed data from a particular highway-rail bridge, the maximum vertical deflection of the bridge deck caused by railway trains reached 94.7 mm, while the vibration amplitude caused by highway vehicles ranged from 0 to 15 mm. The continuous operation of railway trains results in a greater amplitude of vibration on asphalt mixture bridge decks. Previous studies have shown that vibration parameters such as amplitude and frequency affect asphalt viscosity and are closely related to asphalt mixture vibration segregation. Furthermore, vibration segregation is a major cause of early damage to asphalt mixture bridge decks, reducing their service life. Therefore, the unique conditions of train-induced vibration segregation in asphalt mixture bridge decks on highway-rail bridges cannot be ignored.

[0003] However, existing vibration simulation methods and small-scale equipment are not suitable for the special working conditions of train-induced vibration segregation of asphalt mixture bridge deck pavement, and ignore the testing requirements during the actual vibration of the mixture bridge deck pavement, making it difficult to effectively and stably simulate the impact of asphalt mixture vibration segregation. Specifically, there are two main technical problems:

[0004] First, the vibration excitation source must be adapted to the train's vibration conditions. Existing vibration simulation equipment can generate vibration excitation from three main sources: hydraulic, pneumatic, and electric motors. Hydraulic drives can provide high driving force, but are typically equipped with energy storage devices, making the equipment bulky and difficult to use as a vibration excitation source for small devices. Pneumatic drives are well adapted to the working environment, but air is highly compressible, and its vibration stability is significantly affected by load changes. Electric motors offer convenient speed adjustment and high accuracy, but suffer from low driving force. Using high-driving-force motors is expensive and bulky, making them difficult to use for small vibration equipment.

[0005] Second, the equipment must meet the testing requirements for vibration segregation of asphalt bridge deck pavement. First, the on-site construction temperature of asphalt mixtures can reach 180°C, far exceeding the ambient temperature. During vibration testing, the resulting temperature segregation can interfere with the test results. Second, the high loads and long, uninterrupted travel times of railway trains generate the unique vibration conditions of bridge deck pavement, resulting in larger amplitudes. During vibration testing, interfering lateral vibration fluctuations are likely to occur, reducing the test results and making it difficult to reproduce realistic vibration conditions.

[0006] Patent CN111207935 discloses a broadband, large-displacement vibration simulation exciter suitable for high-speed tracked vehicle road simulation. This exciter utilizes hydraulic drive to achieve low-friction, broadband, large-displacement vibration simulation, with a displacement of ±150mm, an excitation force of 200kN, and an adjustable excitation frequency of 0.1-50Hz. However, the device struggles to maintain stable vibration during large-displacement vibration, making it unsuitable for testing vibration segregation in asphalt-mixed bridge deck pavement. Furthermore, the device incorporates an energy storage device, resulting in a bulky system and low efficiency for small-scale vibration simulation experiments.

[0007] Patent CN107014578 discloses a simulation experimental device and experimental method for the impact of vehicles on cast-in-place concrete on bridge decks. By changing the speed regulating motor and the adjusting screw, different vibration frequencies of 0-5Hz and amplitudes of 0-10mm are achieved, simulating the traffic conditions of vehicles passing through the bridge deck. However, the patent uses a cam in direct contact with the top plate, and then transmits force through the table bracket and support spring vibration. At a large amplitude, the vibration will reduce the force transmission effect of the support spring, resulting in irregular vibration. At the same time, if asphalt mixture bridge deck pavement is used to test vibration segregation, the asphalt mixture scatters heat to the environment, and the resulting temperature segregation will interfere with the test effect of the asphalt mixture vibration segregation.

[0008] Patent CN108225704 discloses a vibration simulation device for a dual-use highway-rail bridge. This device achieves varying vibration frequencies and amplitudes by varying the speed of a speed-regulating motor and adjusting an eccentric wheel. While this device utilizes a stable motor excitation source, asphalt mixture density ranges from 2000 to 3000 kg / m³. Further consideration is needed to ensure driving efficiency for higher amplitude vibrations under heavy loads.

[0009] In summary, a method and apparatus for testing train-induced vibration segregation in asphalt bridge pavements is needed. This method and apparatus can adapt to the unique operating conditions of train-induced vibration segregation in asphalt mixture bridge pavements on highway-railway bridges, ensure the driving efficiency of the vibration excitation source to achieve a larger amplitude under asphalt mixture load, and consider the test temperature and vibration stability requirements during actual bridge pavement vibration. This method can be used to simulate train-induced vibration segregation in asphalt mixture bridge pavements, which will be beneficial in promoting technological innovation in bridge pavement vibration simulation. Summary of the Invention

[0010] The purpose of the present invention is to provide a method and device for testing the vibration segregation of asphalt bridge deck pavement caused by trains. Taking into account the testing requirements during the actual vibration process of asphalt mixture bridge deck pavement, the present invention overcomes the problem that the existing related vibration methods and equipment are difficult to effectively and stably simulate the working conditions of the vibration segregation of asphalt mixture bridge deck pavement caused by trains on highway and railway bridges. The present invention can be used to test the vibration segregation of asphalt mixture bridge deck pavement caused by trains.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a method for testing train-induced vibration segregation of asphalt bridge pavement, comprising the following steps:

[0013] Step 1: collecting vibration data of the bridge deck asphalt pavement and obtaining multiple train-induced bridge deck pavement vibration curve time history diagrams; the train-induced bridge deck pavement vibration curve time history diagram is drawn from the bridge deck pavement vibration data when a train passes; the vibration data is the vibration amplitude;

[0014] Step 2: Obtain the adaptive vibration amplitude V s and adaptive vibration frequency f s , in order to adapt the vibration test device, including:

[0015] Step 2A: Based on the multiple train-induced bridge deck pavement vibration curve time histories obtained in step 1, after eliminating redundant vibration data outside the curves, determine the amplitude region boundary values ​​V1, V2, and V3; wherein V1≤V2<V3;

[0016] Step 2B: Define the low frequency band of bridge deck pavement amplitude R1=[0, V1], R3=[V3, V m ] and the amplitude high frequency band R2=[V2, V3], where V m is the maximum amplitude observed;

[0017] Step 2C: Based on the time history graphs of multiple train-induced bridge deck pavement vibration curves, analyze the representativeness and stability of R1 and R3, and select the high-frequency amplitude band R2 as the typical working condition of bridge deck asphalt pavement vibration;

[0018] Step 2D: Select any vibration amplitude as the adaptive vibration amplitude V s , V s ∈R2, V s The train-induced bridge pavement vibration time in the train-induced bridge pavement vibration curve time history diagram is used as the adaptive vibration time t s 、V s The train-induced bridge deck vibration frequency of the train-induced bridge deck vibration curve time history diagram is used as the adaptive vibration frequency fs ;

[0019] Step 3: Based on the equivalent conversion formula, V s and f s , calculate the speed n of the variable frequency motor of the adaptive vibration excitation module in the vibration test device s and the eccentricity R of the adjustable eccentric s ;

[0020] The vibration test device includes an adaptive vibration excitation module and a vibration test module. The vibration test module is used to provide a stable vibration test platform that meets the asphalt mixture test requirements; the adaptive vibration excitation module converts the NR s The amplitude is transmitted to the vibration test module; where N ≥ 2;

[0021] Among them, the equivalent conversion formula is:

[0022] n s =60f s / p,R s =V s / N; p is the number of magnetic poles;

[0023] Step 4: After setting up the vibration test device based on step 3, select different target specimens in the test scenario to conduct vibration test simulation of the bridge deck asphalt pavement.

[0024] Preferably, in step 2C, for the low-frequency amplitude bands R1 and R2, the number of time-history graphs of the train-induced bridge deck pavement vibration curve accounts for 25%; for the high-frequency amplitude band R3, the number of time-history graphs of the train-induced bridge deck pavement vibration curve accounts for 50%.

[0025] Preferably, in step 3, the maximum radius R of the eccentric wheel m Greater than the maximum amplitude V in the vibration condition m , adjusted R m -V m =L, L≥5cm.

[0026] Preferably, in step 3, N=2.

[0027] Preferably, in step 4, based on the temperature test requirements of actual bridge deck asphalt paving materials during testing, the vibration test module is set to be a thermal insulation vibration test module.

[0028] In a second aspect, the present invention provides a train-induced vibration segregation testing device for bridge asphalt pavement, comprising:

[0029] Adaptive vibration excitation module, used to set the vibration excitation source and change the vibration frequency f s and vibration amplitude v s To provide typical working conditions of train-induced vibration segregation of bridge asphalt pavement;

[0030] The buffering and stabilizing force transmission module is used to ensure the buffering and stabilizing effect of the device in the typical working condition of the vibration separation, and avoid the influence of the fluctuation of the lateral vibration; the buffering and stabilizing force transmission module will V s The amplitude is transmitted from the adaptive vibration excitation module to the thermal insulation vibration test module;

[0031] The thermal insulation vibration test module is used to provide a stable vibration test platform to meet the test requirements of the test temperature and vibration stability of the bridge deck asphalt pavement during the vibration process.

[0032] Preferably, the adaptive vibration excitation module includes:

[0033] Stable base;

[0034] A force transmission plate, a spring bracket and a spring, wherein the lower end of the spring bracket is fixed to the stable base, and the spring is fixed between the upper end of the spring bracket and the lower end surface of the force transmission plate to achieve stable transmission of the amplitude;

[0035] The support plate, vertical track, amplitude amplification plate and concave slider are all located below the force transmission plate; the support plate and vertical track are fixed to the stable base and arranged relative to each other, the concave slider is sleeved on the vertical track and can slide along the vertical track to achieve dynamic vibration with amplitude amplification; one end of the amplitude amplification plate is rotatably connected to the support plate, and the other end is hinged to the outer side surface of the concave slider;

[0036] An adjustable frequency motor, an eccentric wheel and a roller, wherein the output shaft of the adjustable frequency motor is connected to the eccentric wheel; the roller is in rolling contact with the eccentric wheel; the center of rotation of the roller is installed on the roller fixing rod, and the roller fixing rod is fixed to the lower surface of the amplitude amplification plate, so that the amplitude is amplified from the roller fixing rod to the end of the concave slider.

[0037] Preferably, the buffering stabilization force transmission module includes a plurality of magnet stabilization components, each of which includes:

[0038] The hollow support frame and the fixed magnet are provided. The outer bottom of the hollow support frame is fixed to the upper surface of the force transmission plate. The inner bottom of the hollow support frame is bonded with a fixed magnet, and the inner upper part thereof is provided with a movable magnet. The movable magnet and the fixed magnet have the same poles facing each other.

[0039] The movable magnet is connected to the lower end surface of the vibration plate of the thermal insulation vibration test module through a connecting rod; the area of ​​the movable magnet is smaller than the cross-sectional area of ​​the hollow support frame.

[0040] Preferably, the thermal insulation vibration test module further includes:

[0041] A loading test fixture is used to make a target test piece and is detachably mounted at the center of the vibration plate;

[0042] The stabilizing plate and bolts and nuts are used to ensure uniform vibration of the material in the test tool. The stabilizing plate is fixed to the periphery of the loading test tool and connected to the corresponding holes of the vibration plate by bolts and nuts;

[0043] The thermal insulation cotton and the thermal insulation cover prevent the temperature segregation of the asphalt mixture from affecting the test effect of vibration segregation. The thermal insulation cotton is arranged on the outer side and bottom of the test tool; the thermal insulation cover is arranged on the top of the loading test tool.

[0044] Compared with the prior art, the advantages of the present invention are:

[0045] (1) The method includes the establishment of a vibration simulation model and the setting of a vibration test device. First, historical data on the vibration of the asphalt pavement of a highway bridge caused by railway trains in the scenario is obtained; then, based on the vibration data, the typical vibration conditions of the test target are determined, wherein the typical vibration conditions include vibration amplitude, vibration frequency and duration, and the vibration simulation model is established; then, based on the vibration simulation model and the equivalent conversion formula, the vibration test device is adaptively set to ensure the driving efficiency of the device. Finally, different target specimens are selected in conjunction with the test in the test scenario, and the test requirements of the test temperature and vibration stability of the actual bridge deck asphalt pavement material during the test are considered, and then a simulation test is performed.

[0046] (2) The vibration test device introduces an amplitude amplification component (support plate, amplitude amplification plate, roller fixing rod and concave slider) to ensure the driving efficiency of the motor excitation source with a larger amplitude under the load of asphalt mixture; the magnet stabilization component is fixed at the key point to avoid vibration fluctuation; and an insulation vibration test module is set up to prevent the temperature segregation of the asphalt mixture from affecting the test effect of vibration segregation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flow chart of the vibration segregation test method of the present invention;

[0048] Figure 2 is a perspective view of the vibration separation test device of the present invention;

[0049] Figure 3 is a plan view of the adaptive vibration excitation module in the device of the present invention;

[0050] Figure 4 is a three-dimensional diagram of the magnet stabilization assembly in the device of the present invention;

[0051] Figure 5 It is a plan view of the thermal insulation vibration test module in the device of the present invention;

[0052] Figure 6 It is a time history diagram of the bridge deck pavement vibration curve caused by a train.

[0053] Among them, 1-stable base, 2-spring bracket, 3-motor bracket, 4-adjustable frequency motor, 5-eccentric wheel, 6-roller, 7-roller fixing rod, 8-spring, 9-force transmission plate, 10-hollow support frame, 11-fixed magnet, 12-moving magnet, 13-connecting rod, 14-vibration plate, 15-loading test fixture, 16-bolts and nuts, 17-stabilizing plate, 18-vertical track, 19-concave slider, 20-support plate, 21-amplitude amplification plate, 22-insulation cotton, 23-insulation cover. Implementation Method

[0054] The following is a more detailed description of the train-induced vibration segregation testing method and apparatus for bridge asphalt pavement according to the present invention, with reference to schematic diagrams. These schematic diagrams illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as generally known to those skilled in the art and is not intended to limit the present invention.

[0055] Reference Figure 1 The embodiment of the present invention provides a method for testing train-induced vibration segregation of bridge asphalt pavement, which performs vibration segregation testing based on the bridge asphalt pavement process, including the following steps:

[0056] Step 1: Collect bridge deck asphalt pavement vibration data and obtain multiple train-induced bridge deck pavement vibration curve time history diagrams.

[0057] The train-induced bridge deck pavement vibration curve time history diagram is drawn from the bridge deck pavement vibration data when a train passes. The vibration data is the vibration amplitude.

[0058] When the train starts to pass, the bridge pavement vibrates. After the train passes, the pavement vibration stops. This time is the vibration duration.

[0059] The vibration frequency is measured using vibration sensors installed on the bridge deck and refers to the number of times the asphalt pavement vibrates vertically in a single second. The vibration duration is measured using a timer associated with the vibration sensors. The adaptive vibration duration is defined as the time it takes for a train to pass over the main bridge of the road-rail bridge.

[0060] Specifically, on-site measurements of bridge pavement vibration data were conducted at the main bridge deck of a specific highway-railway bridge under analysis. Based on the measured 24-hour vibration data for the highway bridge, vibration data during peak train traffic hours was selected. The vibration data before and after each train passage were plotted as a vibration curve time history. The time history of the bridge pavement vibration amplitude, frequency, and time over time were analyzed.

[0061] Step 2: Determine the typical vibration conditions of the bridge asphalt pavement and obtain the adaptive vibration amplitude V s and adaptive vibration frequency f s , to make adaptive settings for the vibration test device.

[0062] The typical vibration conditions include vibration amplitude, vibration frequency and duration.

[0063] Specifically include:

[0064] Step 2A: Based on the multiple train-induced bridge deck pavement vibration curve time history diagrams obtained in step 1, after eliminating redundant vibration data outside the curves, determine the amplitude region boundary values ​​V1, V2 and V3; wherein V1≤V2<V3.

[0065] Step 2B: Define the low frequency band of bridge deck pavement amplitude R1=[0, V1], R3=[V3, V m ] and the amplitude high frequency band R2=[V2, V3], where V m is the maximum amplitude observed.

[0066] Step 2C: Based on multiple train-induced bridge deck pavement vibration curve time history diagrams, analyze the representativeness and stability of R1 and R3, and select the high-frequency amplitude band R2 as the typical working condition of bridge deck asphalt pavement vibration.

[0067] Analysis Process: For low-amplitude frequency bands R1 and R2, the number of train-induced bridge pavement vibration time-history graphs accounted for 25%; for high-amplitude band R3, the number of train-induced bridge pavement vibration time-history graphs accounted for 50%. Considering the poor representativeness and instability of bands R1 and R2, it was determined that the typical operating condition of bridge pavement vibration lies in high-amplitude band R3.

[0068] Step 2D: Select any vibration amplitude as the adaptive vibration amplitude V s , V s ∈R2, V s The train-induced bridge pavement vibration time in the train-induced bridge pavement vibration curve time history diagram is used as the adaptive vibration time t s 、V s The train-induced bridge deck vibration frequency of the train-induced bridge deck vibration curve time history diagram is used as the adaptive vibration frequency f s .

[0069] Step 3: Based on the equivalent conversion formula, amplitude amplification principle, V s (mm) and f s (Hz), calculate the speed n of the frequency-adjustable motor 4 of the adaptive vibration excitation module in the vibration test device s (rpm) and the eccentricity R of the adjustable eccentric 5 s (mm).

[0070] Specifically, the amplitude amplification principle is based on the lever principle to achieve amplitude amplification, by setting a roller fixing rod 7 at the lower part of the amplitude amplification plate 21 at a distance 1 / N from the support plate 20, the amplitude R s The amplitude NR is expanded to the end of the amplitude amplifier plate 21 and the concave slider 19. s , that is, the adaptive vibration amplitude V s , realize the amplitude from R s to V s of the amplification.

[0071] The vibration test device includes an adaptive vibration excitation module and a vibration test module. The vibration test module is used to provide a stable vibration test platform. The adaptive vibration excitation module converts the NR s The amplitude is transmitted to the vibration test module; where N ≥ 2; the equivalent conversion formula is:

[0072] n s =60f s / p,R s =V s / N; p is the number of magnetic pole pairs.

[0073] Wherein, each time the vibration test device vibrates up and down once, the eccentric wheel 5 rotates one circle, and the shaft of the frequency-adjustable motor 4 rotates one circle.

[0074] The key is to introduce the amplitude amplifier board 21 into the excitation module to ensure the driving efficiency of the motor excitation source with a larger amplitude under the load of asphalt mixture. That is, the amplitude R at the roller fixing rod 7 is realized by the amplitude amplifier board 21. s Amplitude V at the concave slider 19 s enlarge.

[0075] Each time the frequency-adjustable motor 4 rotates one circle, it drives the eccentric wheel 5 to rotate one circle, causing the amplitude amplification plate 21 to vibrate up and down once. Due to the arrangement of the amplitude amplification assembly (support plate 20, amplitude amplification plate 21, roller fixing rod 7 and concave slider 19), the amplitude of the eccentric wheel 5 under the amplitude amplification plate 21 is R s The distance from the support plate 20 to this position is 1 / N of the distance to the end of the amplitude amplification plate 21. Based on the lever principle, the amplitude is amplified to NR at the end of the amplitude amplification plate 21. s , which is the adaptive vibration amplitude V s , and the device will have an amplitude of V s Transfer to the vibration test module.

[0076] Specifically, the support plate 20 is used as a fulcrum. By setting a roller fixing rod 7 at the lower part of the amplitude amplifying plate 21 at a distance 1 / N from the support plate, vibration power is provided at this position. The horizontal distance from the fulcrum of the support plate 20 is the power arm. The horizontal distance from the concave slider 19 at the end of the amplitude amplifying plate 21 to the fulcrum of the support plate is the resistance arm. Based on the relationship that the resistance arm is N times the power arm, the amplitude R from the roller fixing rod 7 is realized. s Zoom in to the end of the concave slider and the amplitude NR s , that is, the adaptive vibration amplitude V s .

[0077] Based on the temperature test requirements of actual bridge deck asphalt pavement materials during testing, the vibration test module is set as an insulation vibration test module to avoid the impact of temperature segregation of asphalt mixture on the test effect of vibration segregation.

[0078] Step 4: After setting up the vibration test device based on step 3, select different target specimens in the test scenario to conduct vibration test simulation of the bridge deck asphalt pavement.

[0079] Reference Figures 2 to 5 An embodiment of the present invention provides a train-induced bridge asphalt pavement vibration separation test device, including an adaptive vibration excitation module, a buffering stability transmission module and a thermal insulation vibration test module.

[0080] Adaptive vibration excitation module, used to set the vibration excitation source and change the vibration frequency f s and vibration amplitude v s To provide typical working conditions of train-induced vibration segregation of bridge asphalt pavement;

[0081] The buffering and stabilizing force transmission module is used to ensure the buffering and stabilizing effect of the device under the typical working conditions of vibration separation, and avoid the influence of lateral vibration fluctuations; the buffering and stabilizing force transmission module will V s The amplitude is transmitted from the adaptive vibration excitation module to the thermal insulation vibration test module;

[0082] The thermal insulation vibration test module is used to provide a stable vibration test platform to meet the test requirements of the test temperature and vibration stability of the bridge deck asphalt pavement during vibration.

[0083] Specifically, the adaptive vibration excitation module includes: a stable base 1, a force transmission plate 9, a spring bracket 2, a spring 8, a support plate 20, a vertical track 18, an amplitude amplification plate 21 and a concave slider 19.

[0084] The force transmission plate 9, spring bracket 2, and spring 8 are connected. The lower end of the spring bracket 2 is fixed to the stable base 1, and the spring 8 is fixed between the upper end of the spring bracket 2 and the lower end surface of the force transmission plate 9 to achieve stable transmission of amplitude. That is, springs 8 are installed at the four corners of the stable base 1 and at both ends of the concave slider 19 to connect with the force transmission plate 9, achieving stable transmission of large amplitudes.

[0085] The support plate 20, the vertical track 18, the amplitude amplification plate 21 and the concave slider 19 are all located below the force transmission plate 9; the support plate 20 and the vertical track 18 are fixed to the stable base 1 and are arranged relative to each other, and the concave slider 19 is sleeved on the vertical track 18 and can slide along the vertical track 18 to achieve dynamic vibration with amplitude amplification; one end of the amplitude amplification plate 21 is rotatably connected to the support plate 20, and the other end is hinged to the outer side surface of the concave slider 19.

[0086] Specifically, a U-shaped groove for accommodating the vertical track 18 is provided on the concave slider 19 , the groove is open toward one side of the support plate 20 , and a roller body is provided on the inner wall of the groove toward the support plate 20 , and the roller body is in rolling contact with the vertical track 18 .

[0087] A gap is left between the amplitude amplifying plate 21 and the vertical track 18 to prevent interference between the two. The amplitude amplifying plate 21 is hinged to the side of the groove facing the support plate 20 (ie, the outer side of the concave slider 19).

[0088] A motor bracket 3 is placed on the stable base 1 , and a targeted frequency-adjustable motor 4 and an eccentric wheel 5 with adjustable eccentricity are placed on the motor bracket 3 to provide a special working condition of train-induced vibration segregation of the bridge deck pavement.

[0089] The adjustable frequency motor 4, the eccentric wheel 5 and the roller 6, the output shaft of the adjustable frequency motor 4 is connected to the eccentric wheel 5; the roller 6 is in rolling contact with the eccentric wheel 5; the center of rotation of the roller 6 is installed on the roller fixing rod 7 to ensure stable upward force transmission; the roller fixing rod 7 is fixed to the center of the lower surface of the amplitude amplification plate 21, and the amplitude is amplified from the center (roller fixing rod 7) to the end of the concave slider 19, ensuring the driving efficiency of the motor excitation source with a larger amplitude under the load of asphalt mixture.

[0090] The eccentric wheel 5 with adjustable eccentricity is provided with a slide groove within the radius range, and is connected to the rotating shaft of the frequency-adjustable motor 4 through the connecting hole on the slide groove, thereby changing the eccentricity R of the eccentric wheel 5 s , thereby realizing targeted dynamic adjustment of the amplitude of the test device.

[0091] The maximum radius R of the eccentric 5 m Greater than the maximum amplitude V in the vibration condition m , adjusted R m -V m =L, L≥5cm.

[0092] The variable-frequency motor 4 can be a YCT 112-4A / B horizontal electromagnetic speed-regulating motor with a nominal power of 0.55 / 0.75 kW, achieving a speed of 125-1230 r / min. Its dimensions are 150 mm × 280 mm × 520 mm (width × height × length). It is fixed to the lower motor bracket 3, which must be ≥ 80 mm high to ensure safe and stable rotation of the eccentric 5 at maximum amplitude.

[0093] The buffering stabilization force transmission module includes several magnet stabilization components, which are fixed at the upper center of the force transmission plate 9 and the four corners (key points). The magnet stabilization components include: a hollow support frame 10, a fixed magnet 11 and a movable magnet 12.

[0094] The hollow support frame 10 and the fixed magnet 11, the outer bottom of the hollow support frame 10 is fixed to the upper surface of the force transmission plate 9; the inner bottom of the hollow support frame 10 is bonded with a fixed magnet 11, and the upper part thereof is provided with a movable moving magnet 12, and the moving magnet 12 and the fixed magnet 11 are opposite to each other with the same poles.

[0095] The movable magnet 12 is connected to the lower end surface of the vibration plate 14 of the thermal insulation vibration test module through a connecting rod 13 ; the area of ​​the movable magnet 12 is smaller than the cross-sectional area of ​​the hollow support frame 10 .

[0096] Specifically, the area of ​​the fixed magnet 11 is consistent with that of the hollow support frame 10, and the area of ​​the movable magnet 12 is 50% to 70% of the fixed magnet 11. This module is used to ensure a certain buffering and stabilizing effect under train-induced bridge deck vibration isolation conditions, avoiding the impact of lateral vibration fluctuations.

[0097] The thermal insulation vibration test module includes: a vibration plate 14 , a loading test fixture 15 , a stabilizing plate 17 , bolts and nuts 16 , thermal insulation cotton 22 and a thermal insulation cover 23 .

[0098] The loading test piece 15 is detachably mounted at the center of the vibration plate 14 and is a plate-shaped test piece with a size of 300mm×300mm×100mm or a cylindrical test piece with a size of 101.6mm×87mm, which is used to subsequently produce asphalt mixture rutting plates or Marshall specimens (target specimens).

[0099] The stabilizing plate 17 and the bolts and nuts 16 are used to ensure uniform vibration of the material in the test tool. The stabilizing plate 17 is fixed to the periphery of the loading test tool 15 and is connected to the corresponding holes of the vibration plate 14 through the bolts and nuts 16.

[0100] The thermal insulation cotton 22 and the thermal insulation cover 23 prevent the temperature segregation of the asphalt mixture from affecting the test effect of vibration segregation. The thermal insulation cotton 22 is set on the outer side and bottom of the test tool; the thermal insulation cover 23 is set on the top of the loading test tool 15.

[0101] In this vibration separation test device, the plane dimensions of the stable base 1, force transmission plate 9 and vibration plate 14 are all 1m×1m, the force transmission plate 9 and vibration plate 14 have the same thickness of 5cm, and the thickness of the stable base 1 is 2 to 3 times that of the force transmission plate 9 or vibration plate 14.

[0102] The working principle of the train-induced bridge asphalt pavement vibration separation test device is to adjust the speed n of the variable frequency motor 4. s and the eccentricity R of the adjustable eccentric 5 s , to achieve the vibration amplitude of the roller fixing rod 7 on the amplitude amplification plate 21, which is V s / 2, frequency is f s , and then through the amplitude amplification plate 21, the amplitude V at the roller fixing rod 7 is realized. s / 2 to the concave slider 19 with an amplitude of V s Finally, the vibration amplitude V is amplified by the buffering and stabilizing force transmission module. s The vibration is transmitted to the vibration plate 14 to simulate the typical working conditions of the train-induced vibration of the bridge asphalt pavement.

[0103] Based on the above-mentioned train-induced vibration segregation test method and device for bridge asphalt pavement, the following describes the specific implementation process of the vibration segregation test device for a road-rail bridge project example.

[0104] Step 1: Based on a highway-railway bridge to be analyzed, the bridge deck pavement vibration data is measured on-site at the main bridge deck of the bridge. The measured highway bridge deck pavement vibration data and the train traffic conditions at all times are recorded within 24 hours.

[0105] Due to the lengthy testing period and the large amount of complex vibration data collected, vibration data from peak train traffic hours were selected for analysis. Peak traffic hours for this highway-railway bridge are from 9:00 AM to 12:00 PM. A time-history graph of the bridge deck pavement vibration data during peak hours was analyzed. The vibration data from each train before and after each train passage was plotted as a vibration time-history graph.

[0106] Step 2: Determine typical vibration isolation conditions for the bridge asphalt pavement test target. Based on vibration data from a road-rail bridge, a train passing over the main bridge at a high speed causes vibration. The main truss and upper orthotropic plate deform together, resulting in vertical vibrations far greater than lateral vibrations. Therefore, the vibration data for unstable bridge pavement was eliminated.

[0107] One of the train-induced bridge deck vibration curve time history diagram is shown in Figure 6 , the longitudinal length is the length reached by the train travel time.

[0108] Based on the peak period bridge pavement vibration data time history diagram, the key amplitude values ​​V1, V2 and V3 (V1<V2<V3) are determined. Among them, V1=V2=45mm and V3=74mm are determined, and the low frequency band of bridge pavement amplitude is defined as R1=[0,45], R3=[74, V m ] and the amplitude high frequency band R2=[45,74].

[0109] Analysis shows that the proportion of vibration curves in the low-frequency amplitude range R1=[0,45] is 25.6%. In this range, the amplitude is small and continuously unstable, and the data in this range is less representative.

[0110] The proportion of vibration curves is R3=[74, V m ] section is 23.1%. In this section, there is a heavy-loaded freight train passing through, but the amplitude of this section is not in line with the normal situation.

[0111] The proportion of vibration curves in the R2=[45,74] interval is 51.3%. This interval is a high-frequency amplitude range, where the amplitude is concentrated and the amplitude curve is highly representative. It can be used as a typical working condition for bridge deck pavement vibration research.

[0112] Select the adaptive vibration amplitude V within the R2 range s is 74mm, and the corresponding adaptive vibration frequency f s is 12Hz and the adaptive vibration time t s The vibration simulation model of the asphalt pavement of the highway-railway bridge is established in 12 seconds. Specifically, the adaptive vibration frequency f s The amplitude V collected by the vibration sensor s Vibration frequency at 74mm, adaptive vibration time t s The duration of bridge deck pavement vibration caused by train running.

[0113] Step 3, based on the adaptive vibration amplitude Vs, adaptive vibration frequency fs and adaptive vibration time ts in the vibration simulation model, the vibration separation test device used in the present invention is calculated and set, including the speed n of the adjustable frequency motor 4 s (rpm) and the eccentricity R of the adjustable eccentric 5 s (mm).

[0114] The speed n of the adjustable frequency motor 4 can be calculated s The eccentric moment R of the adjustable eccentric wheel 5 is 720rpm. s The setting of the vibration simulation device is completed.

[0115] The equivalent conversion formula is:

[0116] n s=60f s / p,R s =V s / 2; p is the number of magnetic pole pairs.

[0117] Among them, due to the setting of the amplitude amplification component in the adaptive vibration excitation module, the large amplitude of 74mm of the vibration plate 14 is effectively reduced by half to the amplitude of 37mm above and below the roller 6, ensuring the driving efficiency of the motor excitation source with a larger amplitude under the asphalt mixture load.

[0118] Step 4: Conduct vibration test simulation of the bridge deck asphalt pavement. Different bridge deck asphalt pavement specimens are produced according to the vibration simulation stage and specimen type requirements.

[0119] For example, if it is necessary to simulate the influence of train vibration on the asphalt mixture during paving and before rolling, the asphalt mixture is mixed in proportion, a layer of tack coat oil is spread inside the detachable loading test fixture 15, and the asphalt mixture is installed in the loading test fixture 15.

[0120] If it is necessary to simulate the impact of train vibration during the rolling process of the asphalt mixture after the paving process, the number of wheel rollings of the asphalt mixture can be halved compared to the conventional number of wheel rollings, and then tack coat oil is also spread in the loading test fixture 15, and the asphalt mixture is installed in the loading test fixture 15.

[0121] Specifically, during the construction of the upper highway bridge deck, trains operated continuously below. The construction of asphalt mixtures generally involves mixing, paving, multiple rolling, and curing. During the paving process, the asphalt mixture is not yet formed on the bridge deck before rolling. Therefore, during simulation tests, the asphalt mixture is mixed and then loaded into the test fixture. If the asphalt mixture is not fully formed during the rolling process after paving, the number of rolling cycles can be halved during simulation tests.

[0122] Finally, stabilizing plates 17 surrounding the loading fixture 15 are connected to the corresponding holes in the vibration plate 14 using bolts and nuts 16 to ensure the stability of the fixture's vibration. Furthermore, the exterior sides and bottom of the loading fixture 15 are equipped with insulation 22, and the top is equipped with an insulation cover 23 to prevent temperature segregation of the asphalt mixture from affecting the vibration segregation test results.

[0123] The type of removable test fixture is primarily determined by the amount of asphalt mixture required for subsequent asphalt test specimens, ensuring uniform vibration of the asphalt mixture within the fixture. For a 300mm x 300mm x 100mm plate-shaped test fixture, the asphalt mixture required is suitable for making rutting plate specimens; for a 101.6mm x 87mm cylindrical test fixture, the asphalt mixture required is suitable for making Marshall specimens.

[0124] Turn on the adjustable frequency motor 4 to simulate the special working condition of the asphalt mixture bridge deck pavement caused by the train, and observe the asphalt mixture specimen at the vibration amplitude V s =74mm, vibration frequency f s =12Hz and vibration duration 12s. The actual vibration environment set by the device is consistent with the design requirements and can effectively simulate the special working condition of train-induced vibration segregation of asphalt mixture bridge deck pavement.

[0125] After the vibration is completed, the test fixture is disassembled, the asphalt mixture bridge deck pavement specimen is taken out, and other relevant segregation index tests are carried out.

[0126] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. A method for testing train-induced vibration segregation of bridge asphalt pavement, characterized in that: The steps include: Step 1: collecting vibration data of the bridge deck asphalt pavement and obtaining multiple train-induced bridge deck pavement vibration curve time history diagrams; the train-induced bridge deck pavement vibration curve time history diagram is drawn from the bridge deck pavement vibration data when a train passes; the vibration data is the vibration amplitude; Step 2: Obtain the adaptive vibration amplitude V s and adaptive vibration frequency f s , in order to adapt the vibration test device, including: Step 2A: Based on the multiple train-induced bridge deck pavement vibration curve time histories obtained in step 1, after eliminating redundant vibration data outside the curves, determine the amplitude region boundary values ​​V1, V2, and V3; wherein V1≤V2<V3; Step 2B: Define the low frequency band of bridge deck pavement amplitude R1=[0, V1], R3=[V3, V m ] and the amplitude high frequency band R2=[V2, V3], where V m is the maximum amplitude observed; Step 2C: Based on multiple train-induced bridge deck pavement vibration curve time histories, analyze the representativeness and stability of R1 and R3, and select the high-frequency amplitude band R2 as the typical working condition of bridge deck asphalt pavement vibration; Step 2D: Select any vibration amplitude as the adaptive vibration amplitude V s , V s ∈R2, V s The train-induced bridge pavement vibration time in the train-induced bridge pavement vibration curve time history diagram is used as the adaptive vibration time t s 、V s The train-induced bridge deck vibration frequency of the train-induced bridge deck vibration curve time history diagram is used as the adaptive vibration frequency f s ; Step 3: Based on the equivalent conversion formula, V s and f s , calculate the speed n of the variable frequency motor of the adaptive vibration excitation module in the vibration test device s and the eccentricity R of the adjustable eccentric s ; The vibration test device includes an adaptive vibration excitation module and a vibration test module. The vibration test module is used to provide a stable vibration test platform that meets the asphalt mixture test requirements. The adaptive vibration excitation module transmits the NRs amplitude to the vibration test module. Wherein, N ≥ 2; Among them, the equivalent conversion formula is: n s =60f s / p,R s =V s / N; p is the number of magnetic poles; Step 4: After setting up the vibration test device based on step 3, select different target specimens in the test scenario to conduct vibration test simulation of the bridge deck asphalt pavement.

2. The train-induced vibration segregation test method for bridge asphalt pavement according to claim 1, characterized in that: In step 2C, for the low-frequency amplitude bands R1 and R2, the number of time-history graphs of the train-induced bridge deck pavement vibration curve accounts for 25%; for the high-frequency amplitude band R3, the number of time-history graphs of the train-induced bridge deck pavement vibration curve accounts for 50%.

3. The train-induced vibration segregation test method for bridge asphalt pavement according to claim 1, characterized in that: In step 3, the maximum radius R of the eccentric wheel m Greater than the maximum amplitude V in the vibration condition m , adjusted R m -V m =L, L≥5cm.

4. The train-induced vibration segregation test method for bridge asphalt pavement according to claim 1, characterized in that: In step 3, N=2.

5. The train-induced vibration segregation test method for bridge asphalt pavement according to claim 1, characterized in that: In step 4, based on the temperature test requirements of the actual bridge deck asphalt paving material during testing, the vibration test module is set to a thermal insulation vibration test module.

6. A train-induced vibration segregation testing device for bridge asphalt pavement, used to perform the train-induced vibration segregation testing method for bridge asphalt pavement according to any one of claims 1 to 5, characterized in that: include: Adaptive vibration excitation module, used to set the vibration excitation source and change the vibration frequency f s and vibration amplitude V s To provide typical working conditions of train-induced vibration segregation of bridge asphalt pavement; The buffering and stabilizing force transmission module is used to ensure the buffering and stabilizing effect of the device in the typical working condition of the vibration separation, and avoid the influence of the fluctuation of the lateral vibration; the buffering and stabilizing force transmission module will V s The amplitude is transmitted from the adaptive vibration excitation module to the thermal insulation vibration test module; The thermal insulation vibration test module is used to provide a stable vibration test platform to meet the test requirements of the test temperature and vibration stability of the bridge deck asphalt pavement during the vibration process.

7. The train-induced bridge asphalt pavement vibration segregation testing device according to claim 6, characterized in that: The adaptive vibration excitation module includes: Stable base; A force transmission plate, a spring bracket and a spring, wherein the lower end of the spring bracket is fixed to the stable base, and the spring is fixed between the upper end of the spring bracket and the lower end surface of the force transmission plate to achieve stable transmission of the amplitude; The support plate, vertical track, amplitude amplification plate and concave slider are all located below the force transmission plate; the support plate and vertical track are fixed to the stable base and arranged relative to each other, the concave slider is sleeved on the vertical track and can slide along the vertical track to achieve dynamic vibration with amplitude amplification; one end of the amplitude amplification plate is rotatably connected to the support plate, and the other end is hinged to the outer side surface of the concave slider; An adjustable frequency motor, an eccentric wheel and a roller, wherein the output shaft of the adjustable frequency motor is connected to the eccentric wheel; the roller is in rolling contact with the eccentric wheel; the center of rotation of the roller is installed on the roller fixing rod, and the roller fixing rod is fixed to the lower surface of the amplitude amplification plate, so that the amplitude is amplified from the roller fixing rod to the end of the concave slider.

8. The train-induced bridge asphalt pavement vibration segregation testing device according to claim 7, characterized in that: The buffering stabilization force transmission module includes a plurality of magnet stabilization components, each of which includes: The hollow support frame and the fixed magnet are provided. The outer bottom of the hollow support frame is fixed to the upper surface of the force transmission plate. The inner bottom of the hollow support frame is bonded with a fixed magnet, and the inner upper part thereof is provided with a movable magnet. The movable magnet and the fixed magnet have the same poles facing each other. The movable magnet is connected to the lower end surface of the vibration plate of the thermal insulation vibration test module through a connecting rod; the area of ​​the movable magnet is smaller than the cross-sectional area of ​​the hollow support frame.

9. The train-induced bridge asphalt pavement vibration segregation testing device according to claim 8, characterized in that: The thermal insulation vibration test module also includes: A loading test fixture is used to make a target test piece and is detachably mounted at the center of the vibration plate; The stabilizing plate and bolts and nuts are used to ensure uniform vibration of the material in the test tool. The stabilizing plate is fixed to the periphery of the loading test tool and connected to the corresponding holes of the vibration plate by bolts and nuts; The thermal insulation cotton and the thermal insulation cover prevent the temperature segregation of the asphalt mixture from affecting the test effect of vibration segregation. The thermal insulation cotton is arranged on the outer side and bottom of the test tool; the thermal insulation cover is arranged on the top of the loading test tool.

Images