Fabricated test device and test method for measuring normal mechanical parameters of interlayer interface of ballastless track
By using prefabricated testing devices and methods, and utilizing the self-alignment assembly of pre-reserved fixing holes and positioning screws, as well as the measurement of normal mechanical parameters by jack sensors, the complexity and data shortage problems of interlayer interface measurement of ballastless track were solved, realizing rapid and accurate normal mechanical performance testing and numerical simulation support.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEST JIAOTONG UNIV
- Filing Date
- 2026-01-09
- Publication Date
- 2026-05-08
AI Technical Summary
Existing test devices for measuring the cohesion parameters of interlayer interfaces in ballastless tracks suffer from problems such as complex measurement procedures, inconvenient operation, and insufficient data volume, and are difficult to accurately reflect the interlayer mechanical properties under service conditions.
This invention provides an assembly-type testing device and method, which achieves self-alignment assembly by using a pre-reserved fixing hole and a positioning screw with rigid matching. It combines a jack and a sensor to measure normal mechanical parameters, and obtains the normal force-displacement relationship curve and key parameters through linear and exponential fitting.
This method enables rapid and accurate testing of the normal mechanical properties of the interlayer interface in ballastless tracks, providing a theoretical basis for numerical simulation and damage analysis. It also solves the problems of measurement complexity and insufficient data, and improves the simplicity and accuracy of the measurement.
Smart Images
Figure CN121994594A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ballastless track interface mechanics technology, specifically to an assembled testing device and method for measuring the normal mechanical parameters of the interlayer interface of ballastless track. Background Technology
[0002] By the end of 2024, China's high-speed railway operating mileage had reached 48,000 kilometers, accounting for more than 70% of the world's total high-speed railway mileage, making it the country with the longest high-speed railway operating mileage, the highest commercial operating speed, the most complete technical system, and the most diverse application scenarios in the world. Slab track, due to its advantages such as high stability, excellent smoothness, and low maintenance costs, is widely used in high-speed railway construction. The ballastless track structure typically includes multiple layers such as precast track slabs, cement emulsified asphalt mortar (CA mortar) filling layers, and concrete support layers or base plates. The material properties of each layer differ significantly, and the interlayer mechanical behavior is complex.
[0003] Reliable bonding between the structural layers of ballastless track plays a crucial role in the service performance, durability, and stability of high-speed railway ballastless track beds. However, under the coupled and repeated effects of environmental factors such as temperature and humidity and train dynamic loads, the interlayer interfaces are prone to performance degradation and changes in contact state, leading to periodic unevenness of the track slab, which seriously affects driving comfort and safety, and exacerbates wheel-rail dynamic interaction.
[0004] Currently, my country's ballastless track has entered a large-scale operation and maintenance phase. With the accumulation of operating time, defects such as interlayer gaps occur frequently, exhibiting characteristics such as clustering, suddenness, and recurrence. Therefore, accurately obtaining the interlayer mechanical properties of ballastless track and assessing interface damage behavior are of great significance for ensuring the high smoothness, high stability, and high safety of high-speed railways.
[0005] In existing technologies, such as patent CN114593989B, an assembled measuring device and method are disclosed. Although this scheme has the advantages of assembly, the test relies on the lifting platform of the first / second fixed device for manual leveling. This adjustment method is not only cumbersome to operate, but also makes it difficult to ensure the absolute alignment of the specimen and the base plate. More importantly, patent CN114593989B only obtains the original force-displacement relationship curve and lacks a reliable constitutive model for fitting the experimental data.
[0006] In the prior art, patent CN114839053B discloses a method for detecting interlayer interface damage, which obtains the mechanical parameters of the interlayer interface through interlayer splitting and shear tests. However, the test method used in this patent differs from the normal force form experienced by the actual track interlayer under train load and temperature, making it difficult to determine the interlayer mechanical properties that truly reflect the interface under service conditions.
[0007] Therefore, in order to accurately obtain the normal mechanical parameters of the interlayer interface of ballastless track and provide reliable input for numerical simulation, it is urgent to develop a simple and accurate experimental device and method. Summary of the Invention
[0008] To address the problems of complex measurement procedures, inconvenient operation, and insufficient data in existing experimental devices for measuring the cohesion parameters of the interlayer interface in ballastless track, this invention provides an assembled experimental device and method for measuring the normal mechanical parameters of the interlayer interface in ballastless track. The device has a compact structure, is easy to install and test, and is equipped with a simple and reliable measurement and calculation method to obtain the normal force-displacement relationship curve and key normal cohesion parameters of the interlayer interface in ballastless track. This provides a theoretical basis and data support for the numerical simulation and damage analysis of the interlayer interface behavior of ballastless track, and enables rapid and accurate testing of the normal mechanical properties of the interlayer interface. The obtained parameters can be directly used for damage simulation analysis of ballastless track, thus solving the problems mentioned in the background art.
[0009] To achieve the above objectives, the present invention provides the following technical solution: an assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track, the device comprising a jacking specimen and a measuring platform, wherein the measuring platform is provided with a left-side fixing device and a right-side fixing device for fixing the jacking specimen at its center, the jacking specimen comprising an upper concrete specimen and a lower concrete specimen, the lower concrete specimen having a reserved fixing hole for fixing the jacking specimen.
[0010] Preferably, both the left-side fixing device and the right-side fixing device include an internal angle steel, a fixing screw, and an external clamping plate. The internal angle steel and the external clamping plate are fixedly connected to the push-up specimen through the cooperation of the fixing screw and the clamping screw hole.
[0011] Preferably, the measuring platform includes a test base plate, fixing holes, and positioning screws. The measuring platform is fixedly connected to the left and right fixing devices by the positioning screws passing through the positioning screw holes and fixing holes.
[0012] On the other hand, to achieve the above objectives, the present invention also provides the following technical solution: a test method for measuring the normal mechanical parameters of the interlayer interface of ballastless track, comprising the following steps: S1. Hoist the completed concrete jacking test specimen onto the measuring platform, and use the positioning screws to initially position the jacking test specimen on the measuring platform; S2. Connect the internal angle steel to the measuring platform through the matching of the positioning screw and the positioning screw hole, and accurately adjust the position of the concrete jacking specimen according to the position of the internal angle steel; S3. The internal angle steel and the external clamping plate are fixedly connected to the jacking test piece by means of the fixing screw and several clamping screw holes; S4. Install the displacement sensor on the upper surface of the upper concrete specimen and connect it to the data acquisition instrument. S5. Place the jack, pressure sensor, and loading plate in sequence at the center of the measurement platform; S6. Control the jacks to apply vertical preload so that the loading plate fits tightly against the upper concrete specimen; S7. By controlling the vertical thrust applied by the jack, the loading rate of the jack is controlled and kept uniform until the specimen fails. S8. After the test is completed, unload the jacking force, then disassemble the displacement sensor and pressure sensor in sequence, and finally disassemble the left and right fixing devices. S9. The automatic data acquisition instrument records the vertical displacement of the upper concrete specimen on both sides. And the vertical thrust F, thus obtaining the normal force-displacement relationship curve of the interlayer interface of the ballastless track, and calculating the normal mechanical parameters of the interlayer interface between the track slab and the mortar layer.
[0013] Preferably, the method for calculating the normal mechanical parameters is as follows: S91. Apply vertical thrust to the central area of the concrete block using jacks, ensuring that the vertical thrust applied to the interlayer interface on both sides of the concrete block is equal, and the interface normal displacement is equal. The calculation formula is as follows: ; In the formula, This represents the normal displacement of the upper left concrete specimen. This represents the normal displacement of the upper right concrete specimen. S92. For the jacking test specimen, the upper concrete specimen is bonded to the lower concrete specimen. Assuming the lower concrete specimen is completely fixed to the measuring platform, a normal force will be generated at the interface under the vertical jacking force of the jack. The interface normal stress is... The calculation formula is as follows: ; In the formula, Let A be the interface normal stress and A be the interface bond area. The calculation formula is: , This represents the bond interface area on the left side of the concrete specimen. This represents the bond interface area on the right side of the concrete specimen. S93. Fit the constitutive model of the inter-layer interface obtained from the mechanical parameter measurement of the ballastless track inter-layer interface, including linear fitting of the ascending segment and exponential fitting of the descending segment, to obtain the normal cohesion model diagram of the ballastless track inter-layer interface. Gradually load until interface failure to obtain the normal stress of the inter-layer interface. Relationship curve; S94. The interlayer fracture energy is used to characterize the energy consumed per unit area at the interlayer interface during the fracture process. It corresponds to the area enclosed by the stress-displacement curve and the horizontal axis. The calculation formula is as follows:
[0014] In the formula, d Describes the differential operator. This represents the normal fracture energy at the interlayer interface.
[0015] Preferably, in step S93, during the rising segment... When the normal stress does not reach the interface normal strength Interface normal stiffness Represented as: ; When the normal stress reaches the interface strength Subsequently, as the interface displacement increases, damage begins to appear at the interlayer interface, entering the descent phase. In the descent phase, the interface normal stress is expressed as: ; In the formula, D For damage factors, 0 < D <1, its calculation formula is: .
[0016] The beneficial effects of this invention are as follows: The assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track adopts a rigid matching of pre-reserved fixing holes and positioning screws, realizing self-alignment assembly. The device can determine the normal mechanical properties of the interlayer interface of ballastless track under actual service conditions. This invention also includes the development of complete calculation methods for linear fitting of the ascending segment and exponential fitting of the descending segment, which can directly derive the constitutive parameters required for numerical simulation. Furthermore, it includes simple and reliable measurement and calculation methods for obtaining the normal force-displacement relationship curve and key normal cohesion parameters of the interlayer interface of ballastless track, providing theoretical basis and data support for numerical simulation and damage analysis of the interlayer interface behavior of ballastless track. Attached Figure Description
[0017] Figure 1 A schematic diagram of an assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track; Figure 2 A schematic diagram of the structure and fixing device of the assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track. Figure 3 A schematic diagram of the assembly of a prefabricated test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track. Figure 4 The curve showing the normal force-displacement relationship at the interlayer interface of ballastless track. Figure 5 A schematic diagram of the normal cohesion model of the interlayer interface of ballastless track. In the figure, 1-pushing specimen; 101-upper concrete specimen; 102-lower concrete specimen; 2-left side fixing device; 201-internal angle steel; 202-fixing screw; 203-external clamping plate; 204-clamping screw hole; 205-positioning screw hole; 3-right side fixing device; 4-measuring platform; 401-test base plate; 402-fixing hole; 403-positioning screw. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. It should also be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0021] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0022] Please see Figures 1-2This invention provides a technical solution: an assembled testing device for measuring the normal mechanical parameters of the interlayer interface of ballastless track, such as... Figure 1 As shown, the device includes a jacking specimen 1 and a measuring platform 4. The measuring platform 4 is provided with a left fixing device 2 and a right fixing device 3 for fixing the jacking specimen at its center. The jacking specimen 1 includes an upper concrete specimen 101 and a lower concrete specimen 102. The lower concrete specimen has a reserved fixing hole for fixing the jacking specimen.
[0023] like Figure 2 As shown, both the left fixing device 2 and the right fixing device 3 include an internal angle steel 201, a fixing screw 202 and an external clamping plate 203. The internal angle steel 201 and the external clamping plate 203 are fixedly connected to the push-up specimen through the cooperation of the fixing screw 202 and the clamping screw hole 204.
[0024] The measuring platform 4 includes a test base plate 401, a fixing hole 402, and a positioning screw 403. The measuring platform is fixedly connected to the left fixing device 2 and the right fixing device 3 through the positioning screw 403 passing through the positioning screw hole 205 and the fixing hole 402.
[0025] A test method for an assembled test device based on measuring the normal mechanical parameters of the interlayer interface of ballastless track, the assembly diagram is shown below. Figure 3 As shown, the experiment was then conducted, and the experimental method included the following steps: S1. Hoist the completed concrete jacking specimen 1 onto the measuring platform 4, and use the positioning screw 403 to initially position the jacking specimen 1 on the measuring platform 4. S2. Connect the internal angle steel 201 tightly to the measuring platform 4 through the cooperation of the positioning screw 403 and the positioning screw hole 205, and accurately adjust the position of the concrete jacking specimen 1 according to the position of the internal angle steel 201. S3. The internal angle steel 201 and the external clamping plate 203 are fixedly connected to the push test piece 1 through the cooperation of the fixing screw 202 and several clamping screw holes 204. S4. Install the displacement sensor on the upper surface of the upper concrete specimen 101 and connect it to the data acquisition instrument. S5. Place the jack, pressure sensor and loading plate in the center of the measurement platform 4 in sequence; S6. Control the jack to apply vertical preload so that the loading plate is in close contact with the upper concrete specimen 101; S7. By controlling the vertical thrust applied by the jack, the loading rate of the jack is controlled and kept uniform until the specimen fails. S8. After the test is completed, unload the jacking force, then disassemble the displacement sensor and pressure sensor in sequence, and finally disassemble the left fixing device 2 and the right fixing device 3. S9. The automatic data acquisition instrument records the vertical displacement of the upper concrete specimen on both sides. And the vertical thrust F, thus obtaining the normal force-displacement relationship curve of the interlayer interface of the ballastless track, and calculating the normal mechanical parameters of the interlayer interface between the ballastless track slab and the CA mortar layer.
[0026] The specific method for calculating the normal mechanical parameters is as follows: S91. Apply a vertical thrust to the central area of the concrete block using a jack, ensuring that the vertical thrust applied to the interlayer interfaces on both sides of the concrete block is equal. The vertical thrust F and the displacement of the concrete block can be measured using an axial force gauge and an LVDT displacement meter. Interface normal displacement The calculation formula is as follows: ; In the formula, This represents the normal displacement of the upper left concrete specimen. This represents the normal displacement of the upper right concrete specimen. S92. For the jacking test specimen, the upper concrete specimen is bonded to the lower concrete specimen. Assuming the lower concrete specimen is completely fixed to the measuring platform, a normal force will be generated at the interface under the vertical jacking force of the jack. The interface normal stress is... The calculation formula is as follows: ; In the formula, Let A be the interface normal stress and A be the interface bond area. The calculation formula is: , This represents the bond interface area on the left side of the concrete specimen. This represents the bond interface area on the right side of the concrete specimen. S93. Gradually apply load until interface failure, and obtain the interlayer interface normal stress. Relationship curve, such as Figure 4 As shown; the constitutive model of the inter-layer interface obtained from the measurement of mechanical parameters of the ballastless track inter-layer interface is fitted, including linear fitting of the ascending segment and exponential fitting of the descending segment, to obtain the normal cohesion model diagram of the ballastless track inter-layer interface, as shown. Figure 5 As shown. It can be represented as:
[0027] In the formula, The normal bond strength at the interlayer interface. For the corresponding normal displacement, This represents the normal displacement at the interlayer gap. c This is the coefficient for the descending segment.
[0028] In the rising phase, that is When the normal stress does not reach the interface normal strength Interface normal stiffness Represented as: ; When the normal stress reaches the interface strength Subsequently, as the interface displacement increases, damage begins to appear at the interlayer interface, entering the descent phase. In the descent phase, the interface normal stress is expressed as: ; In the formula, D For damage factors, 0 < D <1, its calculation formula is: .
[0029] S94. The interlaminar fracture energy is used to characterize the energy consumed per unit area at the interlaminar interface during the fracture process, which corresponds to the area enclosed by the stress-displacement curve and the horizontal axis. Figure 5 The area of the gray region in the image is calculated using the following formula:
[0030] In the formula, This represents the normal fracture energy at the interlayer interface.
[0031] The assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track of the present invention adopts the rigid matching of the reserved fixing hole and the positioning screw to realize self-alignment assembly. The device can measure the normal mechanical properties of the interlayer interface of ballastless track under actual service conditions.
[0032] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. An assembled testing device for measuring the normal mechanical parameters of the interlayer interface of ballastless track, characterized in that, The device includes a jacking specimen (1) and a measuring platform (4). The measuring platform (4) is provided with a left-side fixing device (2) and a right-side fixing device (3) for fixing the jacking specimen. The jacking specimen (1) includes an upper concrete specimen (101) and a lower concrete specimen (102). The lower concrete specimen has a reserved fixing hole for fixing the jacking specimen.
2. The assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track according to claim 1, characterized in that: The left-side fixing device (2) and the right-side fixing device (3) both include an internal angle steel (201), a fixing screw (202) and an external clamping plate (203). The internal angle steel (201) and the external clamping plate (203) are fixedly connected to the push-up specimen through the cooperation of the fixing screw (202) and the clamping screw hole (204).
3. The assembled test device for measuring the normal mechanical parameters of the interlayer interface of ballastless track according to claim 1, characterized in that: The measuring platform (4) includes a test base plate (401), a fixing hole (402), and a positioning screw (403). The measuring platform is fixedly connected to the left fixing device (2) and the right fixing device (3) by the positioning screw (403) passing through the positioning screw hole (205) and the fixing hole (402).
4. A test method for an assembled test apparatus for measuring the normal mechanical parameters of the interlayer interface of ballastless track according to any one of claims 1-3, characterized in that: Includes the following steps: S1. Hoist the completed concrete jacking test specimen (1) onto the measuring platform (4) and use the positioning screw (403) to initially position the jacking test specimen (1) on the measuring platform (4); S2. Connect the internal angle steel (201) to the measuring platform (4) through the positioning screw (403) and the positioning screw hole (205), and adjust the position of the concrete jacking specimen (1) precisely according to the position of the internal angle steel (201); S3. The internal angle steel (201) and the external clamping plate (203) are fixedly connected to the push test piece (1) through the cooperation of the fixing screw (202) and several clamping screw holes (204); S4. Install the displacement sensor on the upper surface of the upper concrete specimen (101) and connect it to the data acquisition instrument. S5. Place the jack, pressure sensor and loading plate in the center of the measuring platform (4) in sequence; S6. Control the jack to apply vertical preload so that the loading plate is in close contact with the upper concrete specimen (101); S7. By controlling the vertical thrust applied by the jack, the loading rate of the jack is controlled and kept uniform until the specimen fails. S8. After the test is completed, unload the jacking force, then disassemble the displacement sensor and pressure sensor in sequence, and finally disassemble the left fixing device (2) and the right fixing device (3). S9. The automatic data acquisition instrument records the vertical displacement of the upper concrete specimen on both sides. And the vertical thrust F, thus obtaining the normal force-displacement relationship curve of the interlayer interface of the ballastless track, and calculating the normal mechanical parameters of the interlayer interface between the track slab and the mortar layer of the ballastless track.
5. The test method for measuring the normal mechanical parameters of the interlayer interface of ballastless track according to claim 4, characterized in that: The specific method for calculating the normal mechanical parameters is as follows: S91. Apply vertical thrust to the central area of the concrete block using jacks, ensuring that the vertical thrust applied to the interlayer interface on both sides of the concrete block is equal, and the interface normal displacement is equal. The calculation formula is as follows: ； In the formula, This represents the normal displacement of the upper left concrete specimen. This represents the normal displacement of the upper right concrete specimen. S92. For the jacking test specimen, the upper concrete specimen is bonded to the lower concrete specimen. Assuming the lower concrete specimen is completely fixed to the measuring platform, a normal force will be generated at the interface under the vertical jacking force of the jack. The interface normal stress is... The calculation formula is as follows: ； In the formula, Let A be the interface normal stress and A be the interface bond area. The calculation formula is: , This represents the bond interface area on the left side of the concrete specimen. This represents the bond interface area on the right side of the concrete specimen. S93. Fit the constitutive model of the inter-layer interface obtained from the mechanical parameter measurement of the ballastless track inter-layer interface, including linear fitting of the ascending segment and exponential fitting of the descending segment, to obtain the normal cohesion model diagram of the ballastless track inter-layer interface. Gradually load until interface failure to obtain the normal stress of the inter-layer interface. Relationship curve; S94. The interlayer fracture energy is used to characterize the energy consumed per unit area at the interlayer interface during the fracture process. It corresponds to the area enclosed by the stress-displacement curve and the horizontal axis. The calculation formula is as follows: ； In the formula, This represents the normal fracture energy at the interlayer interface.
6. The test method for measuring the normal mechanical parameters of the interlayer interface of ballastless track according to claim 5, characterized in that: In step S93, during the rising segment, i.e. When the normal stress does not reach the interface normal strength Interface normal stiffness Represented as: ； When the normal stress reaches the interface strength Subsequently, as the interface displacement increases, damage begins to appear at the interlayer interface, entering the descent phase. In the descent phase, the interface normal stress is expressed as: ； In the formula, D For damage factors, 0 < D <1, its calculation formula is: .