Loading test device for mechanical property test of ballast track bed

Abstract

The invention relates to the technical field of track mechanical testing, in particular to a loading test device for mechanical property testing of a ballast track bed, which comprises a railway ballast box for laying railway ballasts; the loading device is arranged above the railway ballast box and is used for simulating the impact of train operation on a ballast track bed; and the supporting device is fixed on the side and the upper part of the railway ballast box and is used for supporting the loading device. The springs are arranged around the railway ballast box to simulate the longitudinal and transverse resistance of the ballast bed, so that the problem that the existing rigid boundary railway ballast box has a boundary effect and cannot simulate the mechanical behavior of the ballast bed under the real boundary-free constraint condition is effectively solved; meanwhile, the loading system is based on a crank connecting rod structure, the defects that an existing drop hammer loading device can only apply instantaneous impact and cannot stably load for a long time are overcome, long-term application of cyclic loads is achieved, meanwhile, the loading frequency and the loading amplitude can be controlled by changing the rotating speed of a motor and the elastic coefficient of a spring in the loading device, and the loading efficiency is improved. And simulation application of loads of different degrees is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of track mechanics testing, in particular to a loading test device for mechanical property testing of a ballast bed. BACKGROUND

[0002] Ballast track is widely used in railway engineering due to its low cost, convenient construction and easy maintenance. As an important part of ballast track, the mechanical properties of the ballast bed directly determine the track support stiffness and damping energy dissipation and control the evolution of track settlement, which is a key factor to ensure the stability of track geometry. The stability of track geometry is directly related to the smoothness and safety of the line. Therefore, ensuring the good mechanical properties of the ballast bed is the premise of ensuring the long-term safe service of the ballast track line, and in-depth study of the mechanical property evolution law of the ballast bed under long-term train load is the key to understanding the mechanical behavior mechanism of the ballast bed and effectively controlling the performance.

[0003] Currently, the research methods of the mechanical property evolution law of the ballast bed mainly include field experiments and laboratory experiments. Although the field experiment can reflect the actual working condition, it has problems such as high test cost, complex detection environment and inability to long-term detection, which leads to the inability to comprehensively measure the mechanical response of the ballast bed under train load and the difficulty in effectively recording the degradation process of the ballast bed caused by long-term cyclic train load. The laboratory experiment usually relies on large dynamic triaxial test equipment, which can simulate the ballast bed and train load under controllable conditions, but also has problems such as high cost and complex operation. Therefore, developing test research based on small laboratory equipment can not only reduce cost and simplify operation, but also facilitate long-term monitoring and comparison, providing a new way to reveal the mechanical property evolution law of the ballast bed. However, the existing small laboratory equipment is mostly a ballast box with rigid boundary, which cannot simulate the actual boundary-free constraint condition of the ballast bed, and the loading system is difficult to apply long-term and stable cyclic load with high frequency, which cannot represent the mechanical property evolution process of the ballast bed under long-term load.

[0004] At present, there is no effective technical solution for small-scale ballast bed mechanical property laboratory test device that can simultaneously simulate the actual ballast bed state and stably apply long-term cyclic load. High Xiaogang et al. (Patent Application No. CN201910464379.4) designed a track system drop hammer impact test machine, which can test the impact performance of the track system by drop hammer loading method, and can simulate the stress response of the track under train load to a certain extent. However, the ballast box used in this device has a rigid boundary structure, which has obvious boundary effect problem and cannot reflect the real mechanical behavior of the ballast bed under actual boundary-free constraint condition. At the same time, the drop hammer loading method belongs to instantaneous impact load, which cannot realize high-frequency and long-term stable load application, so it is not enough to reveal the mechanical property evolution law of the ballast bed under long-term cyclic train load.

[0005] Therefore, there is an urgent need for a small indoor device that can simulate the actual track bed condition and perform long-term loading tests, so as to provide a reliable platform for the study of the evolution law of track bed mechanical properties. Summary of the Invention

[0006] Based on the background technology analysis, it is evident that existing technologies have several shortcomings in studying the evolution of track bed mechanical properties: while field experiments can reflect actual working conditions, they are limited by high costs, complex environments, and difficulties in long-term monitoring, making it impossible to fully reveal the mechanical response of the track bed under train loads, nor to effectively record the track bed deterioration process caused by long-term cyclic loading of trains; large-scale dynamic triaxial testing equipment used in indoor experiments, while realistically simulating track bed and train loads, is costly and cumbersome to operate; currently, small indoor equipment often uses rigid boundary ballast boxes, which are difficult to simulate real unconstrained conditions, and their loading systems cannot achieve long-term stable high-cycle cyclic loading, resulting in an inability to accurately characterize the evolution of track bed mechanical properties under long-term loading. Therefore, to address these shortcomings, the purpose of this invention is to design a small indoor loading testing machine that can simulate the real track bed state and apply loads stably for a long period, while ensuring low cost and easy operation, providing a reliable experimental platform for in-depth revelation of the evolution of track bed mechanical properties. The specific solution is as follows.

[0007] The present invention provides a loading test apparatus for testing the mechanical properties of ballasted track beds, comprising:

[0008] Ballast boxes are used for laying ballast.

[0009] A loading device is installed above the ballast box to simulate the impact of train operation on the ballasted track bed;

[0010] A support device is fixed to the side and top of the ballast box to support the loading device.

[0011] In a further improvement, the support device includes a gantry frame, a support rod, a slider, a sliding rod, and a support plate;

[0012] The support rod is used to mount the gantry frame and a sleeve-shaped slider is fixedly mounted thereon. The sliding rod is slidably connected to the slider, and the support plate is fixedly connected to the sliding rod. The slider serves as a guide between the support rod and the sliding rod, allowing the support rod to move smoothly along the sliding rod and reducing friction and jamming.

[0013] The slider provides a linear guide track for the sliding rod, ensuring its smooth movement in a specific direction.

[0014] Further improvement, the buffer pad is arranged between the sliding block and the support plate, and is used for buffering the collision between the sliding block and the support plate; and the damping block is arranged on the end surface of the support plate, and is used for connecting the support device and the loading device, and buffering the vibration of the loading device.

[0015] Further improvement, the loading device comprises a motor, a transmission conversion mechanism, an energy storage element and a loading plate, the motor drives the transmission conversion mechanism, the transmission conversion mechanism drives the loading plate to vibrate up and down through the energy storage element, and the loading plate abuts against the sleeper and is used for uniformly acting the transmitted force on the sleeper.

[0016] Further improvement, the transmission conversion mechanism comprises a shaft coupling, a crank, a connecting rod and a piston rod, and the energy storage element comprises an upper spring and a lower spring,

[0017] The motor is connected with the shaft coupling to rotate and drive the crank to move in a circle, the connecting rod converts the rotary motion into the reciprocating linear motion of the piston rod, the piston moves up and down in the spring sleeve, and the upper spring and the lower spring are compressed and released, the elastic potential energy of the springs is accumulated and released, and the loading plate is pushed to generate high-frequency reciprocating impact.

[0018] Further improvement, the loading device further comprises an outer cylinder, a sheath and a spring sleeve, the outer cylinder is used for protecting and supporting the internal structure, and guarantees the overall rigidity and stability of the device; the sheath is a vertically telescopic structure, is synchronously telescoped with the reciprocating motion of the spring sleeve during the loading process, is used for protecting the internal elastic element and the transmission component, and avoids the entry of dust and impurities from the outside; and the spring sleeve is used for installing and constraining the spring component,

[0019] Further improvement, the ballast box structure comprises a sleeper, a horizontal inner plate, a vertical inner plate, a horizontal inner shell, an acrylic plate, a ballast box shell and a bottom plate.

[0020] The horizontal inner plate, the vertical inner plate, the horizontal inner shell and the acrylic plate constitute a three-dimensional constraint structure inside the ballast box and store ballast; and the acrylic plate is used for observing the deformation and motion of the ballast inside the box body, and facilitating experimental monitoring and recording.

[0021] The sleeper is arranged in the three-dimensional constraint structure, is used for simulating the sleeper in the actual track structure, and bears and transmits the load.

[0022] Further improvement, the spring plate and the resistance spring are further provided.

[0023] The spring plate and the resistance spring are used in cooperation, and are used for providing longitudinal and transverse resistance for simulating the ballast bed.

[0024] Further improvement, the ballast box shell is a whole bearing structure, ensuring the ballast box overall rigidity and stability; the bottom plate is used for supporting the whole box and fixed on the experiment platform, providing basic support.

[0025] The technical scheme of the present application has the following technical effects:

[0026] (1) The present application arranges springs around the ballast box to simulate the longitudinal and transverse resistance of the ballast bed, effectively solving the problem of the existing rigid boundary ballast box that has boundary effect and cannot simulate the mechanical behavior of the ballast bed under the condition of real no-boundary constraint.

[0027] (2) The loading system is based on a crank connecting rod structure, solving the defect that the existing drop hammer loading device can only apply instantaneous impact and cannot load stably for a long time, realizing long-term application of cyclic load, and through changing the motor speed and the elastic coefficient of the spring in the loading device, the loading frequency and loading amplitude can be controlled, realizing simulation and application of different degrees of train load.

[0028] (3) Combined with the observation window of the ballast box and the linear laser displacement, stress and acceleration sensors arranged, the whole process monitoring of the ballast bed settlement deformation and mechanical response is realized, thereby establishing an experimental research platform for the evolution law of the mechanical properties of the ballast bed under long-term load, providing reliable technical support for understanding the mechanical behavior mechanism of the ballast bed and realizing effective performance control. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings accompanying the specification of this application form a part of the application and serve to further provide a further understanding of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application and do not limit the present application in any way. In the drawings:

[0030] Figure 1 The overall structure of the present application is shown;

[0031] Figure 2 The structure of each component of the support device of the present application is shown;

[0032] Figure 3 The local enlarged structure of the support device of the present application is shown;

[0033] Figure 4 The structure of the loading device of the present application is shown;

[0034] Figure 5 The internal structure of the loading device of the present application is shown;

[0035] Figure 6 The structure of the ballast box of the present application is shown;

[0036] Figure 7 The internal structure of the ballast box of the present application is shown.

[0037] In the figure, 1 - gantry; 2 - support rod; 3 - slider; 4 - sliding rod; 5 - buffer pad; 6 - support plate; 7 - damping block; 8 - motor; 9 - outer cylinder; 10 - sheath; 11 - spring sleeve; 12 - loading plate; 13 - coupling; 14 - crank; 15 - connecting rod; 16 - piston rod; 17 - upper spring; 18 - piston; 19 - lower spring; 20 - sleeper; 21 - transverse inner plate; 22 - vertical inner plate; 23 - transverse inner shell; 24 - acrylic plate; 25 - spring plate; 26 - resistance spring; 27 - ballast box shell; 28 - bottom plate; 29 - handle. DETAILED DESCRIPTION

[0038] The embodiments of the present application will be described in detail with the accompanying drawings and examples, so that the realization process of how to apply technical means to solve technical problems and achieve technical effects of the present application can be fully understood and implemented.

[0039] The structure of the present application is shown in Figure 1 The device can be divided into a support device, a loading device and a ballast box, the ballast box is used for laying ballast, the loading device is arranged above the ballast box and is used for simulating the impact generated by the running of a train, and the loading device is installed on the support device.

[0040] The support device is shown in Figures 2-3 The support device includes a gantry 1, a support rod 2, a slider 3, a sliding rod 4, a buffer pad 5, a support plate 6 and a damping block 7. The gantry 1 is used for supporting the whole device and ensuring the stability of the whole device; the support rod 2 is used for bearing and connecting the slider 3; the slider 3 is installed between the support rod 2 and the sliding rod 4 and plays a guiding and transmission role, so that the support rod 2 can move stably along the sliding rod 4 and reduce friction and jamming; the sliding rod 4 provides a straight guide track for the slider 3 and ensures the stable movement of the slider 3 in a specific direction; the buffer pad 5 is used for buffering the collision between the slider 3 and the support plate 6; the support plate 6 provides stable support for the support rod 2 and ensures the force balance during the loading process; and the damping block 7 is used for connecting the support device and the loading device and buffering the vibration of the loading device.

[0041] The loading device is shown in Figures 4-5As shown, including motor 8, outer tube 9, sheath 10, spring sleeve 11 and loading plate 12. Motor 8 for providing the power required for loading; outer tube 9 for protection and support internal structure, ensure the overall rigidity and stability of the device; sheath 10 is a vertical telescopic structure, the upper part can be synchronized with the reciprocating motion of the spring sleeve telescopic during loading, while used to protect the internal elastic elements and transmission components, to avoid dust and impurities from the outside, its lower part and spring sleeve 11 fixed connection; spring sleeve 11 for installation and constraint spring components, ensure the uniform stress of spring and provide elastic buffer, its lower end connected with the loading plate 12; loading plate 12 is the component directly contact with the sleeper 20, used to transfer the force evenly to the sleeper 20, so as to realize the loading function.

[0042] Loading device internal structure as Figure 5 As shown, the internal structure of the loading device includes coupling 13, crank 14, connecting rod 15, piston rod 16, upper spring 17, piston 18, lower spring 19. Motor 8 drives the coupling 13 rotation, driving crank 14 circular motion, connecting rod 15 converts the rotary motion into reciprocating linear motion of piston rod 16, wherein the piston rod 16 is equipped with a cylindrical slide rail to limit its lateral displacement. Piston 18 moves up and down in the spring sleeve 11, compressing and releasing the upper spring 17 and lower spring 19, the elastic potential energy of the spring is accumulated and released, when the piston 18 moves downward, the upper spring 17 is stretched, exerting a downward tension on the spring sleeve 11, while the lower spring 19 is compressed, also exerting a downward pressure on the spring sleeve 11, the two superimposed push loading plate 12 downward impact; when the piston 18 moves upward, the upper spring 17 is compressed, exerting an upward pressure on the spring sleeve 11, while the lower spring 19 is stretched, also exerting an upward tension on the spring sleeve 11, the two together push loading plate 12 upward rebound. Thus, the two groups of springs in the reciprocating motion of the piston alternately generate the same force, so that the loading plate 12 can obtain elastic driving force in the upward and downward directions, push the loading plate 12 to produce high frequency reciprocating impact, so as to realize the long-term application of the simulation of train wideband load.

[0043] Ballast box structure as Figures 6-7As shown, including the sleeper 20, transverse inner plate 21, vertical inner plate 22, transverse inner shell 23, acrylic plate 24, spring plate 25, resistance spring 26, ballast box shell 27, bottom plate 28 and handle 29. The sleeper 20 is used to simulate the sleeper in the actual track structure, bearing and transmitting load; the transverse inner plate 21, vertical inner plate 22, transverse inner shell 23 and acrylic plate 24 are used to constitute the three-dimensional constraint structure of the ballast box, which plays a supporting role for the track bed, and the three are independently arranged in structure, and are not rigidly connected with each other, so as to ensure that the track bed has a certain degree of freedom around, so as to truly reflect the stress boundary condition of the track bed, and the acrylic plate 24 is used to observe the deformation and movement of the ballast in the box body, which is convenient for experimental monitoring and recording; the spring plate 25 is used in cooperation with the resistance spring 26 to provide longitudinal and transverse resistance of the simulated track bed; the ballast box shell 27 is a whole bearing structure, which ensures the overall stiffness and stability of the ballast box; the bottom plate 28 is used to support the whole box body and is fixed on the experimental platform to provide basic support; the handle 29 is used to carry and move the ballast box.

[0044] The internal structure of the ballast box is as shown in Figure 7 Each side of the ballast box is provided with four sets of combined components of spring plate 25 and spring 26, which are used to provide longitudinal and transverse resistance of the simulated track bed, so as to eliminate the boundary effect problem existing in the traditional ballast box and realize the simulation of the real track bed state.

[0045] Usage instruction:

[0046] Step one: weld and fix the ballast box shell 27, the bottom plate 28 and the handle 29, and place the acrylic plate 24 into the transverse inner shell 23.

[0047] Step two: based on the longitudinal and transverse resistance data of the track bed measured on site, select the spring 26 with appropriate stiffness value to ensure that the longitudinal and transverse resistance of the ballast box meets the actual situation on site, weld the selected spring 26 with the spring plate 25, and connect the welded spring 26 and spring plate 25 with the transverse inner plate 21, vertical inner plate 22, transverse inner shell 23, acrylic plate 24 and ballast box shell 27 through bolts according to the design scheme, and complete the installation of the ballast box.

[0048] Step three: evenly lay ballast in the internal structure of the ballast box composed of the transverse inner plate 21, the two vertical inner plates 22, the transverse inner shell 23 and the acrylic plate 24, and install the sleeper 20.

[0049] Step four: fix the support rod 2 on the gantry 1 through bolts; install and fix the sliding block 3, sliding rod 4, buffer pad 5, support plate 6 and damping block 7 according to the design scheme, and ensure that the sliding block 3 can slide smoothly on the sliding rod 4; connect and fix the support rod 2 and the sliding block 3 through bolts, and complete the installation of the support device.

[0050] Step five: install and debug the loading device to ensure its normal operation. Fix the outer cylinder 9 with the damping block 7 through bolts to complete the connection of the loading device and the fixing device;

[0051] Step six: place the fixed and connected support device and loading device on the ballast box and adjust to the appropriate position to ensure that the loading plate 12 is in uniform contact with the sleeper 20 and to avoid partial load.

[0052] Step six: after completing the overall assembly, start the motor 8 to pre-load and compact the track bed. Stop the motor 8 after loading for a period of time and test the support stiffness of the track bed using the support stiffness tester. When the support stiffness meets the actual track bed requirements, the pre-loading is completed.

[0053] Step seven: start the motor 8 to load the experiment. Since the force of the loading device is generated by the reciprocating inertia force and the weight, in order to involve the weight in the acting force, the loading device needs to release the vertical freedom degree, so the outer cylinder 9 is not rigidly fixed, but is supported by the support rod - slide - slide rod, and is only constrained in the horizontal direction. During the loading process, the outer cylinder 9 moves vertically in the small space between the slide and the damping block, and the displacement amplitude is small. This structural design avoids the rigid fixation of the outer cylinder, allowing its weight to participate in the formation of the loading force, thereby increasing the loading amplitude. On the other hand, by limiting the vertical movement range, it prevents excessive displacement from affecting the stability of the loading process. After starting, the motor 8 drives the piston to move linearly through the shaft coupling, crank, and connecting rod mechanism. The piston alternately compresses and stretches the upper and lower springs during the up and down movement, and the spring sleeve 11 and the loading plate 12 connected at its lower end move linearly in the vertical direction. At the same time, the sheath 10 is a vertically telescopic structure that expands and contracts synchronously with the reciprocating movement of the spring sleeve during the loading process, achieving motion following effect and completing the application of periodic load to the sleeper, realizing the loading function. The loading frequency can be directly controlled by the motor speed, and the loading amplitude can be increased by increasing the elastic coefficient of the spring in the loading device to increase the inertia force.

[0054] Step eight: after starting the loading device, observe the state of the track bed inside the ballast box through the acrylic plate 24, detect the settlement deformation of the track bed based on the line laser displacement sensor, and detect the response changes of the related mechanical parameters of the track bed by embedding stress and acceleration sensors in the ballast box.

[0055] Step nine: after loading for a period of time, turn off the loading device, record the data of each sensor, and analyze the long-term load mechanical performance evolution law of the track bed by organizing and analyzing these data.

[0056] In the embodiment, springs are arranged around the ballast box to simulate the longitudinal and transverse resistance of the track bed, effectively solving the problem of the existing rigid boundary ballast box that has boundary effect and cannot simulate the mechanical behavior of the track bed under the condition of real boundary constraint. Meanwhile, the loading system is based on the crank connecting rod structure, solving the defect that the existing drop hammer loading device can only apply instantaneous impact and cannot be loaded stably for a long time, realizing the long-term application of cyclic load. Meanwhile, the loading frequency and loading amplitude can be controlled by changing the motor speed and the elastic coefficient of the spring of the loading device, realizing the simulation and application of different degrees of train load. On this basis, combined with the ballast box observation window and the linear laser displacement, stress and acceleration sensors arranged, the whole process monitoring of the track bed settlement deformation and mechanical response is realized, thereby establishing an experimental research platform for the evolution law of the track bed mechanical properties under the long-term load, and providing reliable technical support for understanding the track bed mechanical behavior mechanism and realizing effective performance control.

[0057] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A loading test device for testing the mechanical properties of ballasted track, characterized in that, The utility model relates to a kind of loading test device for ballast bed mechanical property test, including: Ballast box for laying ballast; Loading device, which is arranged above the ballast box, is used to simulate the impact of train operation on ballast; Supporting device, fixed on the side and above the ballast box, is used to support the loading device.

2. The loading test device for testing mechanical properties of a ballast bed according to claim 1, characterized by The supporting device includes gantry, supporting rod, sliding block, sliding rod and supporting plate. The supporting rod is installed on the gantry and fixedly installed sleeve-shaped sliding block, the sliding rod is slidingly connected with the sliding block, and the supporting plate is fixedly connected with the sliding rod.

3. The loading test device for testing mechanical properties of a ballast bed according to claim 2, characterized by It also includes a cushion and a damping block, the cushion is arranged between the sliding block and the supporting plate, and the damping block is arranged on the end surface of the supporting plate.

4. The loading test device for testing mechanical properties of a ballast bed according to claim 1, characterized by The loading device includes motor, transmission conversion mechanism, energy storage element and loading plate, the motor drives the transmission conversion mechanism, the transmission conversion mechanism makes the loading plate vibrate up and down through the energy storage element, and the loading plate abuts against the sleeper to uniformly act the transmitted force on the sleeper.

5. The loading test device for testing mechanical properties of a ballast bed according to claim 4, characterized by The transmission conversion mechanism includes shaft coupling, crank, connecting rod and piston rod, and the energy storage element includes upper spring and lower spring. The motor is connected with the shaft coupling to rotate and drive the crank to make circular motion, and the connecting rod converts the rotary motion into reciprocating linear motion of the piston rod.

6. The loading test device for testing mechanical properties of a ballast bed according to claim 5, wherein The loading device also includes outer cylinder, sheath and spring sleeve, the outer cylinder is used to protect and support the internal structure to ensure the overall rigidity and stability of the device, the sheath is a vertically telescopic structure, which telescopes synchronously with the reciprocating motion of the spring sleeve during loading and is used to protect the internal elastic element and transmission components, and the spring sleeve installs and restricts the spring component.

7. The loading test device for testing mechanical properties of a ballast bed according to claim 3, characterized by The ballast box structure includes sleeper, horizontal inner plate, vertical inner plate, horizontal inner shell, acrylic plate, ballast box shell and bottom plate. The horizontal inner plate, vertical inner plate, acrylic plate and horizontal inner shell constitute a three-dimensional constraint structure inside the ballast box, and the sleeper is arranged in the three-dimensional constraint structure to simulate the sleeper in the actual track structure and bear and transmit load.

8. The loading test device for testing mechanical properties of a ballast bed according to claim 7, wherein It also includes spring plate and resistance spring. The spring plate is used in cooperation with the resistance spring to provide longitudinal and transverse resistance to simulate ballast bed.

9. The loading test device for ballast bed mechanical property test according to claim 8, wherein The ballast box shell is a whole load-bearing structure to ensure the overall rigidity and stability of the ballast box, and the bottom plate is used to support the whole box and fixed on the experimental platform to provide basic support.

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