Simulation system and test method for impact of maglev train on track-bed structure

Abstract

The application discloses a simulation system and a test method for impact of a maglev train on a track-bed structure, and can simulate the physical process of the impact of the maglev train on the track-bed structure according to the characteristics of a medium-low speed maglev track transportation. The simulation system for the impact of the maglev train on the track-bed structure comprises a track-bed simulation structure, an excitation structure for exciting the track-bed simulation structure and a data acquisition structure; the excitation structure comprises: a counterweight frame placed on the track-bed simulation structure; counterweight blocks placed in the counterweight frame, the number of the counterweight blocks being set according to requirements; and an excitation mechanism placed on the counterweight frame.

Description

Technical Field

[0001] This invention relates to the technical field of magnetic levitation rail transit, and more specifically, to a simulation system and test method for the impact of magnetic levitation trains on the track-bed structure. Background Technology

[0002] Unlike traditional urban rail transit, maglev trains use powerful electromagnetic forces to levitate above the track while maintaining a certain levitation distance, thus overcoming the limitations of wheel-rail contact in traditional urban rail trains. Maglev trains, relying on electromagnetic levitation, offer advantages such as environmental friendliness, strong climbing ability, small turning radius, low noise, smooth operation, high comfort, high safety, and low construction costs. They are suitable for transportation connections in urban areas, between short-distance cities, and tourist attractions, and can replace light rail and subways.

[0003] For medium- and low-speed maglev railway projects, unlike high-speed railways where post-construction settlement of the roadbed is generally limited to 15mm, the restrictions on roadbed settlement are relaxed, allowing for settlement up to 30mm. However, as a new type of rail transit engineering, current designs for the embankment structure of medium- and low-speed maglev railways are not yet adapted to this specific technical standard. In the few actual engineering designs, high-speed railway design methods are still referenced, resulting in blind conservatism and uneconomical practices. The fundamental reason for this lies in the unclear understanding of the stress mechanisms of the roadbed and track structure under the dynamic action of medium- and low-speed maglev vehicles. Given the existing technical and economic problems with the track structure of medium- and low-speed maglev railways, and the current situation where the roadbed design, mainly referencing high-speed railway roadbed technical standards, has excessive safety reserves leading to uneconomical practices, it is necessary to gain a deeper understanding of the stress mechanisms of new track-bearing beam structures and roadbed structures based on the characteristics of medium- and low-speed maglev rail transit. Among these methods, physical simulation experiments are a crucial research tool for solving this problem. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a physical simulation system and test method that can simulate the physical process of maglev train impacting the track-bed structure according to the characteristics of medium and low speed maglev rail transit.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a simulation system for the impact of a magnetic levitation train on a track-bed structure is provided, the technical solution of which is as follows:

[0006] A simulation system for the impact of a maglev train on a track-base bed structure includes a track-base bed simulation structure, an excitation structure for exciting the track-base bed simulation structure, and a data acquisition structure. The excitation structure includes: a counterweight frame placed on the track-base bed simulation structure; counterweight blocks placed in the counterweight frame, the number of which is set according to requirements; and an excitation mechanism placed on the counterweight frame.

[0007] As a further improvement of the first aspect of the present invention, the track-subgrade simulation structure includes a roadbed body simulation mechanism, a subgrade bottom layer simulation mechanism, a subgrade surface layer simulation mechanism, a cushion layer simulation mechanism, a track beam simulation mechanism, a rail support platform simulation mechanism, a sleeper simulation mechanism, and a rail simulation mechanism connected sequentially from bottom to top, and the counterweight frame is placed on two rail simulation mechanisms.

[0008] As a further improvement of the first aspect of the present invention, the counterweight frame includes: a base plate, the width of which is adapted to the spacing between the two rail simulation mechanisms, and the counterweight block is placed on the base plate; a top plate, which is located above the base plate, and the vibration mechanism is placed on the top plate; and a support column, the upper and lower ends of which are respectively connected to the top plate and the base plate.

[0009] As a further improvement to the first aspect of the present invention, the data acquisition structure includes a dynamic earth pressure box placed between the counterweight frame base plate and the rail simulation mechanism.

[0010] As a further improvement of the first aspect of the present invention, the top plate of the counterweight frame is provided with a rigid rod adapted to the top rod of the excitation mechanism.

[0011] As a further improvement of the first aspect of the present invention, the geometric similarity ratio of the track-bed simulation structure is 1:(2 to 8), and the density similarity ratio is 1:(0.9 to 1.1).

[0012] As a further improvement of the first aspect of the present invention, the roadbed body simulation mechanism is made of sandy clay; the subgrade bottom layer simulation mechanism is made of medium sand; the subgrade surface layer simulation mechanism is made of coarse sand; the cushion layer simulation mechanism is made of coarse sand; the track beam simulation mechanism is made of phenolic plastic with fabric reinforcement; the track support platform simulation mechanism is made of phenolic plastic with fabric reinforcement; the sleeper simulation mechanism is made of concrete; and the rail simulation mechanism is made of wood.

[0013] As a further improvement of the first aspect of the present invention, below the subgrade simulation mechanism, the data acquisition structure includes data acquisition units arranged at intervals along the axial and radial directions of the track-subgrade simulation structure, and the data acquisition units include earth pressure cells, displacement sensors and acceleration sensors distributed in each simulation layer; above the subgrade simulation mechanism, the data acquisition structure includes acceleration sensors and displacement sensors disposed on the subgrade simulation mechanism, and resistance strain gauges, acceleration sensors and displacement sensors disposed on the track beam simulation mechanism.

[0014] As a further improvement of the first aspect of the invention, the excitation mechanism includes an electric exciter, a power amplifier, and a signal generator; and / or, a plurality of excitation structures are arranged at intervals on the track-bed simulation structure.

[0015] To achieve the above objectives, according to a second aspect of the present invention, a test method for the impact of a magnetic levitation train on a track-bed structure is provided, the technical solution of which is as follows:

[0016] The test method for the impact of a maglev train on the track-bed structure adopts the simulation system for the impact of a maglev train on the track-bed structure described in the first aspect above.

[0017] The present invention has the following advantages:

[0018] 1. The simulation system for the impact track-bed structure of a maglev train established in this invention adopts a scaled physical model test method. Based on the main factors affecting the test results of the impact track-bed structure of a maglev train, a model test system is constructed. From the perspective of physical simulation, the dynamic response characteristics and reasonable structural forms of the track beam and embankment bed structure are determined. It can be used for physical simulation research on the reasonable design methods and structural forms of maglev track beams and beds, and has important scientific and practical significance.

[0019] 2. This invention employs a centralized loading excitation device with an excitation mechanism connected to a counterweight frame containing built-in counterweights. This device is simple, convenient, and effectively simulates the vibration load of medium- and low-speed maglev trains on the track-base structure. The number and weight of the counterweights can be adjusted to simulate different magnitudes of excitation force. By changing the vibration waveform, frequency, and amplitude of the excitation mechanism, different combinations of these vibration parameters can simulate vibration load modes of different spectral ranges of maglev trains. Multiple excitation structures can be used to apply multi-point uniform or non-uniform excitation loading to the track-base structure.

[0020] 3. Under limited indoor test site conditions, it can achieve a relatively reasonable physical simulation of the vibration and impact of maglev trains on the track-bed structure. The test is efficient, simple and inexpensive, saving related research funds.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a three-dimensional diagram of the simulation system of the magnetic levitation train impact track-base bed structure in Example 1.

[0024] Figure 2 This is a cross-sectional schematic diagram of the simulation system of the magnetic levitation train impact track-base bed structure in Example 1.

[0025] Figure 3 This is a longitudinal section schematic diagram of the simulation system of the magnetic levitation train impact track-base bed structure in Example 1.

[0026] Figure 4 This is a three-dimensional view of the excitation mechanism in the simulation system of the magnetic levitation train impact track-base bed structure in Example 1.

[0027] Figure 5 This is a schematic diagram of the data acquisition structure layout in the simulation system of the magnetic levitation train impact track-base bed structure in Example 1.

[0028] Figure 6 This is a three-dimensional diagram of the simulation system of the magnetic levitation train impact track-base structure in Example 2.

[0029] Figure 7 This is a schematic diagram of the sleeper simulation mechanism used in the experiment.

[0030] Figure 8 This is a schematic diagram of the track beam simulation mechanism during the test.

[0031] Figure 9 The time history curve is the excitation wave applied during the test.

[0032] Figure 10 The time history curve of vertical acceleration at the midpoint of the top surface of the simulated track beam mechanism obtained from the experiment.

[0033] Figure 11 The time history curve of vertical acceleration at the midpoint of the bottom surface of the simulated track beam mechanism obtained from the experiment.

[0034] Figure 12 This is a diagram showing the maximum compressive stress distribution across the cross section of the simulated track beam mechanism obtained from the experiment.

[0035] Figure 13 This is a diagram showing the maximum tensile stress distribution across the cross-section of the simulated track beam mechanism obtained from the experiment.

[0036] Figure 14 The curve showing the distribution of roadbed settlement along depth for survey line 1 obtained from the experiment.

[0037] Figure 15 The curve showing the ratio of vertical additional stress to the stress on the top surface of the simulated mechanism of the subgrade surface layer, obtained from the experiment, along the depth distribution curve.

[0038] Figure 16 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 1 obtained from the experiment.

[0039] Figure 17 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 2 obtained from the experiment.

[0040] Figure 18 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 3 obtained from the experiment.

[0041] Figure 19 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 4 obtained from the experiment.

[0042] The relevant markings in the above figures are:

[0043] 110 - Track foundation simulation mechanism, 120 - Subgrade bottom layer simulation mechanism, 130 - Subgrade surface layer simulation mechanism, 140 - Cushion layer simulation mechanism, 150 - Track beam simulation mechanism, 160 - Rail support platform simulation mechanism, 170 - Sleeper simulation mechanism, 180 - Rail simulation mechanism, 210 - Counterweight frame, 211 - Base plate, 212 - Top plate, 213 - Support column, 220 - Counterweight block, 230 - Vibration mechanism, 231 - Top rod, 240 - Rigid rod, 310 - Earth pressure box, 320 - Displacement sensor, 330 - Acceleration sensor, 340 - Resistance strain gauge. Detailed Implementation

[0044] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0045] The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0046] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0047] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0048] Example 1

[0049] Figure 1 This is a three-dimensional view of the simulation system of the magnetic levitation train impact track-base structure in this embodiment. Figure 2 This is a cross-sectional schematic diagram of the simulation system of the magnetic levitation train impact track-base bed structure in this embodiment. Figure 3 This is a longitudinal section schematic diagram of the simulation system of the magnetic levitation train impact track-base bed structure in this embodiment. Figure 4 This is a perspective view of the excitation mechanism 230 in the simulation system of the magnetic levitation train impact track-base structure in this embodiment. Figure 5 This is a schematic diagram of the data acquisition structure layout in the simulation system of the magnetic levitation train impact track-base bed structure in this embodiment.

[0050] like Figure 1-5 As shown, the simulation system for the impact of a maglev train on the track-bed structure includes a track-bed simulation structure, an excitation structure for exciting the track-bed simulation structure, and a data acquisition structure.

[0051] The track-subgrade simulation structure includes, from bottom to top, a roadbed body simulation mechanism 110, a subgrade bottom layer simulation mechanism 120, a subgrade surface layer simulation mechanism 130, a cushion layer simulation mechanism 140, a track beam simulation mechanism 150, a rail support platform simulation mechanism 160, a sleeper simulation mechanism 170, and a rail simulation mechanism 180.

[0052] The geometric similarity ratio (i.e., the length ratio) between the track-subgrade simulation structure and the prototype structure is 1:(2-8), and the material density similarity ratio (i.e., the density ratio) is 1:(0.9-1.1). Specifically, the roadbed body simulation mechanism 110 is made of sandy clay; the subgrade bottom layer simulation mechanism 120 is made of medium sand; the subgrade surface layer simulation mechanism 130 is made of coarse sand; the cushion layer simulation mechanism 140 is made of coarse sand; the track beam simulation mechanism 150 is made of phenolic plastic with fabric reinforcement; the rail support platform simulation mechanism 160 is made of phenolic plastic with fabric reinforcement; the sleeper simulation mechanism 170 is made of concrete; and the rail simulation mechanism 180 is made of wood.

[0053] The vibration excitation structure includes a counterweight frame 210, counterweight blocks 220, and a vibration excitation mechanism 230. The counterweight frame 210 is placed on two rail simulation mechanisms 180. The counterweight blocks 220 are placed in the counterweight frame 210, and the number of counterweight blocks 220 is set according to requirements. The vibration excitation mechanism 230 is placed on the counterweight frame 210, and the vibration excitation mechanism 230 includes an electric vibrator, a power amplifier, and a signal generator.

[0054] The counterweight frame 210 includes a base plate 211, a top plate 212, and support columns 213. The width of the base plate 211 is adapted to the spacing between the two rail simulation mechanisms 180, and the counterweight block 220 is placed on the base plate 211. The top plate 212 is located above the base plate 211, and the vibration excitation mechanism 230 is mounted on the top plate 212. The top plate 212 is provided with a rigid rod 240 adapted to the top rod 231 of the vibration excitation mechanism 230. The upper and lower ends of the support columns 213 are connected to the top plate 212 and the base plate 211, respectively, and there are four support columns 213.

[0055] The data acquisition structure is configured as follows: First, the data acquisition structure includes a dynamic earth pressure box 310 placed between the base plate 211 and the rail simulation mechanism 180. To balance the force on the counterweight frame 210, two or four dynamic earth pressure boxes 310 are symmetrically arranged on the two rail simulation mechanisms 180. Second, below the subgrade simulation mechanism 140, the data acquisition structure includes data acquisition units arranged at intervals along the axial and radial directions of the track-subgrade simulation structure. The data acquisition units include dynamic earth pressure boxes 310, displacement sensors 320, and acceleration sensors 330 distributed in each simulation structure layer. To improve the testing effect, dynamic earth pressure boxes 310 are arranged on both the upper and lower sides of the roadbed simulation mechanism 110. In addition, above the subgrade simulation mechanism 140, the data acquisition structure includes an acceleration sensor 330 and a displacement sensor 320 installed on the subgrade simulation mechanism 140, and a resistance strain gauge 340, an acceleration sensor 330, and a displacement sensor 320 installed on the track beam simulation mechanism 150.

[0056] Example 2

[0057] Figure 6 This is a three-dimensional view of the simulation system of the magnetic levitation train impact track-base structure in this embodiment.

[0058] Compared with Example 1, the simulation system for the impact track-bed structure of the maglev train in this embodiment differs in that: Figure 6 As shown, multiple excitation structures are arranged at intervals on the track-bed simulation structure.

[0059] An embodiment of the test method for the impact track-bed structure of the magnetic levitation train of the present invention is a simulation system for the impact track-bed structure of the magnetic levitation train described in one of the above two embodiments.

[0060] The following experimental data illustrates the beneficial effects of the present invention.

[0061] (I) Construction of the simulation system

[0062] 1. The excitation mechanism 230 is a permanent magnet type electric modal exciter that converts electrical energy into mechanical energy to vibrate and impact the rail simulation mechanism 180. Its performance parameters are shown in Table 1. The bottom plate 211 and the top plate 212 are both 240mm×175mm steel plates, and the bottom plate 211 and the top plate 212 are welded together by an L-shaped support column 213. The excitation mechanism 230 is connected to the top plate 212 by bolts. The counterweight 220 is a steel rectangular counterweight 220 with dimensions of 400mm×160mm×10mm and a single block weight of 5.024kg. The side wall height of the counterweight frame 210 is 130mm, which can accommodate up to 12 counterweight blocks 220, and can provide a maximum counterweight of 60.288kg.

[0063] 2. The rail simulation mechanism 180 uses rectangular cross-section timber with a cross-sectional size of 50mm×10mm and a length of 1562.5mm.

[0064] 3. For example Figure 7 As shown, the sleeper simulation mechanism 170 uses an H-shaped sleeper, and the rail simulation mechanism 180 and the sleeper simulation mechanism 170 are connected by bolts.

[0065] 4. The cross-sectional dimensions of the rail support platform simulation mechanism 160 are 52.5mm×50mm×26mm; a shim is provided between the rail support platform simulation mechanism 160 and the sleeper simulation mechanism 170; the rail support platform simulation mechanism 160 and the sleeper simulation mechanism 170 are connected by bolts.

[0066] 5. The track beam simulation mechanism 150 is connected to the track support platform simulation mechanism 160 by bolts; such as Figure 8 As shown, the track beam simulation mechanism 150 is inverted T-shaped and has a length of 1562.5 mm.

[0067] 6. The thicknesses of the roadbed body simulation mechanism 110, the subgrade bottom layer simulation mechanism 120, the subgrade surface layer simulation mechanism 130, and the cushion layer simulation mechanism 140 are 187.5mm, 187.5mm, 62.5mm, and 12.5mm, respectively; the length of the cushion layer simulation mechanism 140 is 1562.5mm and the width is 875mm; the length of the bottom of the roadbed body simulation mechanism 110 is 2437.5mm and the width is 1750mm; the roadbed body simulation mechanism 110, the subgrade bottom layer simulation mechanism 120, the subgrade surface layer simulation mechanism 130, and the cushion layer simulation mechanism 140 are surrounded by slopes, and the ratio of the projected width to the thickness of the slopes is 1.5:1.

[0068] 7. For example Figure 3 As shown, four data acquisition units are set at equal intervals along the length of the track-bed structure, and are named measuring line 1, measuring line 2, measuring line 3 and measuring line 4 respectively. Among them, measuring line 1 and measuring line 4 are located at the center and beam end of the track beam simulation mechanism 150, respectively.

[0069] Table 1

[0070] Maximum excitation force 100N maximum amplitude ±10mm Maximum input current 10 Arms Frequency range DC-4kHz Moving-coil DC resistor 0.8Ω Mass of movable parts 0.5kg Total mass 15kg Configuration efficacy 200W External dimensions ф158×204mm

[0071] Table 2 shows the material and performance parameter values ​​of the track-bed structure actually used in the prior art. Table 3 shows the material and performance parameter values ​​of the track-bed structure in the simulation system of the present invention.

[0072] Table 2

[0073]

[0074] Table 3

[0075]

[0076] In Tables 2 and 3:

[0077] The material parameters of the track-subgrade structure were obtained through material testing methods in accordance with the American standard "Standard Test Methods for Young's Modulus of Elasticity, Tangent Modulus and Tangent Modulus of Tangent (ASTM E111-2004)", the Chinese standards "Code for Design of Concrete Structures (GB50010-2010 (2015 Edition)", "Code for Design of Railway Subgrade (TB 10001-2016)", "Code for Geotechnical Investigation (GB50021-2001)", and "Standard for Geotechnical Testing Methods (GB T 50123-2019)".

[0078] “EI” represents bending stiffness, and “E” represents the modulus of elasticity. It is determined according to the American standard “Standard Test Methods for Young’s Modulus of Elasticity, Tangent Modulus and Shear Modulus of Tangent (ASTM E111-2004)”. After the modulus of elasticity is determined, the bending stiffness is calculated, which is equal to the product of the modulus of elasticity E and the geometric moment of inertia I of the cross section.

[0079] "c" represents the internal friction angle, and "c" represents the cohesion. Both are determined according to the Chinese national standard "Standard for Geotechnical Testing Methods (GBT50123-2019)", specifically by indoor compression test and direct shear test.

[0080] The geometric similarity ratio of Table 3 to Table 2 is 1:8, and the heavy similarity ratio is 1:1.

[0081] Both Group A and Group B fill materials shall be used in accordance with the relevant provisions of the Chinese "Railway Subgrade Design Code (TB 10001-2016)". The classification of sand and clay, as well as the density and coarseness of sand, shall be used in accordance with the relevant provisions of the Chinese "Geotechnical Engineering Investigation Code (GB50021-2001)".

[0082] (II) Test Results

[0083] Figure 9 The time history curve is the excitation wave applied during the test. Figure 10 The time history curve of vertical acceleration at the midpoint of the top surface of the track beam simulation mechanism 150 obtained from the experiment. Figure 11 The time history curve of vertical acceleration at the midpoint of the bottom surface of the track beam simulation mechanism 150 obtained from the experiment.

[0084] Figure 9 To match the model system of this embodiment, a typical magnetic levitation train excitation acceleration time history curve is obtained. The excitation duration is 5.5s, the amplitude is about 0.2g (g is the gravitational acceleration), and the applied vibration wave exhibits typical irregular vibration curve characteristics. Figure 10 This indicates that the vertical acceleration time history at the midpoint of the top surface of the track beam is basically consistent with the applied excitation time history. Figure 11 The vertical acceleration response at the midpoint of the bottom surface of the track beam is weaker than that of the applied excitation acceleration, with an amplitude reduction of approximately 20%.

[0085] Figure 12 The diagram shows the maximum compressive stress distribution across the cross section of the simulated track beam mechanism 150 obtained from the experiment. Figure 13 The diagram shows the maximum tensile stress distribution across the cross section of the simulated track beam mechanism 150 obtained from the experiment.

[0086] Figure 12The results show that the maximum tensile stress in the cross section of the track beam is symmetrically distributed along the longitudinal direction of the beam at typical excitation moments. The maximum tensile stress is the largest at the mid-span section of the model beam, and it reaches its maximum at larger acceleration moments rather than peak acceleration moments, with a value of approximately 390 kPa. This indicates that the maximum tensile stress response of the track beam cross section has a certain hysteresis effect on the excitation wave. Figure 13 The results show that the maximum compressive stress in the cross section of the track beam is symmetrically distributed along the longitudinal direction of the beam at typical excitation moments. The maximum compressive stress is the largest at the mid-span section of the model beam, and it reaches its maximum at larger acceleration moments rather than peak acceleration moments, with a value of approximately 610 kPa. This indicates that the maximum compressive stress response of the track beam cross section also has a certain hysteresis effect on the excitation wave.

[0087] Figure 14 The curve showing the distribution of roadbed settlement along depth for survey line 1 obtained from the experiment. Figure 15 The curve showing the ratio of vertical additional stress to the top surface stress of the simulated subgrade layer 130 along the depth, obtained from the experiment. Figure 16 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 1 obtained from the experiment. Figure 17 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 2 obtained from the experiment. Figure 18 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 3 obtained from the experiment. Figure 19 The graph shows the acceleration variation with depth at the peak of the excitation wave and at the moment of greater acceleration for survey line 4 obtained from the experiment.

[0088] Figure 14 This indicates that at different excitation times, as the depth increases, the settlement deformation in the subgrade below the track beam gradually decreases nonlinearly. For the permanent settlement at the time of vibration, the maximum attenuation amplitude within the test depth range is about 38%. Figure 15 This indicates that the additional stress generated by the vibration load in the subgrade decreases nonlinearly with depth. At a depth of about 0.45m from the top surface of the subgrade of the model, the additional stress of the vibration load is reduced by about 40%. Figures 16-19 All studies show that the acceleration response in the subgrade beneath the track beam decreases nonlinearly with increasing depth. At a depth of approximately 0.45m from the top surface of the subgrade layer of the model, the acceleration in the subgrade is close to zero, indicating that the influence of vibration load is very weak at this location. Meanwhile, the acceleration response at each point in the subgrade is strongest along the survey line at the mid-span of the track beam. Specifically, at the top surface of the subgrade layer of the model, the acceleration is approximately 0.155g. The acceleration response gradually weakens as it moves away from the mid-span survey line, but increases relatively again when it reaches the edge of the track beam.

[0089] exist Figure 12-19 In the middle, the peak acceleration value is 0.191 m / s².2 The maximum acceleration value is 0.134 m / s². 2 The corresponding excitation times were 1.935s and 2.920s, respectively.

[0090] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A simulation system for the impact track-bed structure of a maglev train, characterized in that: This includes a track-bed simulation structure, an excitation structure for vibrating the track-bed simulation structure, and a data acquisition structure; The track-subgrade simulation structure includes, from bottom to top, a roadbed body simulation mechanism (110), a subgrade bottom layer simulation mechanism (120), a subgrade surface layer simulation mechanism (130), a cushion layer simulation mechanism (140), a track beam simulation mechanism (150), a rail support platform simulation mechanism (160), a sleeper simulation mechanism (170), and a rail simulation mechanism (180). The excitation structure includes: A counterweight frame (210) is placed on the track-bed simulation structure; the counterweight frame (210) is placed on two rail simulation mechanisms (180); Counterweight (220), the counterweight (220) is placed in counterweight frame (210), and the number of counterweights (220) is set according to requirements; Vibration mechanism (230), which is placed on counterweight frame (210); The counterweight frame (210) includes: A base plate (211) is provided, the width of which is adapted to the spacing between the two rail simulation mechanisms (180), and a counterweight (220) is placed on the base plate (211). Top plate (212), the top plate (212) is located above the bottom plate (211), and the vibration mechanism (230) is installed on the top plate (212); The support column (213) is connected to the top plate (212) and the bottom plate (211) at its upper and lower ends, respectively.

2. The simulation system as described in claim 1, characterized in that: The data acquisition structure includes a dynamic earth pressure box (310) placed between the base plate (211) and the rail simulation mechanism (180).

3. The simulation system as described in claim 1, characterized in that: The top plate (212) is provided with a rigid rod (240) adapted to the top rod (231) of the excitation mechanism (230).

4. The simulation system as described in claim 1, characterized in that: The geometric similarity ratio of the simulated track-bed structure is 1:(2-8), and the density similarity ratio is 1:(0.9-1.1).

5. The simulation system as described in claim 4, characterized in that: The roadbed body simulation mechanism (110) is made of sandy clay; the subgrade bottom layer simulation mechanism (120) is made of medium sand; the subgrade surface layer simulation mechanism (130) is made of coarse sand; the cushion layer simulation mechanism (140) is made of coarse sand; the track beam simulation mechanism (150) is made of phenolic plastic with fabric reinforcement; the track support platform simulation mechanism (160) is made of phenolic plastic with fabric reinforcement; the sleeper simulation mechanism (170) is made of concrete; and the rail simulation mechanism (180) is made of wood.

6. The simulation system as described in claim 1, characterized in that: Below the cushion layer simulation mechanism (140), the data acquisition structure includes data acquisition units arranged at intervals along the axial and radial directions of the track-subgrade simulation structure. The data acquisition units include earth pressure cells (310), displacement sensors (320), and acceleration sensors (330) distributed in each simulation layer. Above the cushion layer simulation mechanism (140), the data acquisition structure includes an acceleration sensor (330) and a displacement sensor (320) mounted on the cushion layer simulation mechanism (140), and a resistance strain gauge (340), an acceleration sensor (330), and a displacement sensor (320) mounted on the track beam simulation mechanism (150).

7. The simulation system as described in claim 1, characterized in that: The excitation mechanism (230) includes an electric exciter, a power amplifier and a signal generator; and / or, multiple excitation structures are arranged at intervals on the track-bed simulation structure.

8. A test method for the impact track-bed structure of a maglev train, characterized in that: A simulation system for the impact track-bed structure of a magnetic levitation train as described in any one of claims 1-7.

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