CN-121994594-A - Assembled test device and test method for measuring normal mechanical parameters of interface between ballastless track layers

CN121994594ACN 121994594 ACN121994594 ACN 121994594ACN-121994594-A

Abstract

The invention belongs to the technical field of ballastless track interface mechanics, and particularly discloses an assembly type test device and a test method for measuring normal mechanical parameters of an interface between ballastless tracks, wherein the device comprises a pushing test piece and a measurement platform, a left fixing device and a right fixing device for fixing the pushing test piece are arranged in the center of the measurement platform, the pushing test piece comprises an upper concrete test piece and a lower concrete test piece, the lower concrete test piece is provided with a reserved fixing hole for fixing the pushing test piece, the reserved fixing hole is rigidly matched with a positioning screw rod, self-alignment assembly is realized, and a simple and reliable measurement and calculation method is developed in a matched manner, so that a normal force-displacement relation curve and a key normal cohesive force parameter of the interface between ballastless tracks are obtained, and theoretical basis and data support are provided for numerical simulation and damage analysis of interface between ballastless tracks.

Inventors

LIU YU
SUN XIAODAN
HE AN
YIN ZIHAN
HUA CHENGJIE
YIN MAOQING

Assignees

西南交通大学

Dates

Publication Date: 20260508
Application Date: 20260109

Claims (6)

1. The assembled test device for measuring normal mechanical parameters of interfaces between ballastless track layers is characterized by comprising a pushing test piece (1) and a measuring platform (4), wherein a left fixing device (2) and a right fixing device (3) for fixing the pushing test piece are arranged at the center of the measuring platform (4), the pushing test piece (1) comprises an upper concrete test piece (101) and a lower concrete test piece (102), and the lower concrete test piece is provided with a reserved fixing hole for fixing the pushing test piece.
2. The assembly type test device for measuring normal mechanical parameters of interfaces between ballastless track layers according to claim 1, wherein the left side fixing device (2) and the right side fixing device (3) comprise an inner angle steel (201), a fixing screw (202) and an outer clamping plate (203), and the inner angle steel (201) and the outer clamping plate (203) are fixedly connected with a pushing test piece through the cooperation of the fixing screw (202) and the clamping screw hole (204).
3. The assembly type test device for measuring normal mechanical parameters of interfaces between ballastless track layers according to claim 1, wherein the measurement platform (4) comprises a test bottom plate (401), a fixing hole (402) and a positioning screw (403), and the measurement platform is fixedly connected with the left fixing device (2) and the right fixing device (3) through the positioning screw (403) penetrating through the positioning screw hole (205) and the fixing hole (402).
4. A test method of the assembly type test device for measuring normal mechanical parameters of an interface between ballastless track layers according to any one of claims 1 to 3, which is characterized by comprising the following steps: S1, hoisting the manufactured concrete pushing test piece (1) onto a measuring platform (4), and primarily positioning the pushing test piece (1) on the measuring platform (4) through a positioning screw (403); S2, tightly connecting the internal angle steel (201) with the measuring platform (4) through the matching of the positioning screw (403) and the positioning screw hole (205), and accurately adjusting the position of the concrete pushing test piece (1) according to the position of the internal angle steel (201); S3, fixedly connecting the inner angle steel (201) and the outer clamping plate (203) with the pushing test piece (1) through the cooperation of the fixing screw rods (202) and the clamping screw holes (204); S4, mounting a displacement sensor on the upper surface of the upper concrete test piece (101) and connecting the displacement sensor with a data acquisition instrument; s5, sequentially placing the jack, the pressure sensor and the loading plate in the center of the measuring platform (4); S6, controlling the jack to apply vertical pre-pressure so that the loading plate is tightly attached to the upper concrete test piece (101); S7, vertically applying thrust by controlling the jack, and controlling the loading rate of the jack and keeping uniform until the test piece is damaged; S8, after the test is finished, unloading the jacking force of the jack, then sequentially disassembling the displacement sensor and the pressure sensor, and finally disassembling the left fixing device (2) and the right fixing device (3); S9, recording vertical displacement of the left side and the right side of the upper concrete test piece by an automatic data acquisition instrument And vertical thrust force F, so that a normal force-displacement relation curve of an interlayer interface of the ballastless track is obtained, and a normal mechanical parameter of the interlayer interface between the ballastless track plate and the mortar layer is obtained through calculation.
5. The test method for measuring normal mechanical parameters of the interface between ballastless track layers of claim 4, wherein the normal mechanical parameter calculation method is specifically as follows: S91, applying vertical thrust to the middle area of the concrete block through the jack, and ensuring that the vertical thrust applied to the interlayer interfaces at the left side and the right side of the concrete block are equal, and enabling the interfaces to be displaced normally The calculation formula of (2) is as follows: ; in the formula, Is the normal displacement of the left upper concrete test piece, Normal displacement of the concrete test piece at the upper part of the right side; s92, for the pushing test piece, the upper concrete test piece is bonded with the lower concrete test piece, and if the lower concrete test piece is completely fixed with the measuring platform, normal force is generated at the interface under the action of the vertical pushing force of the jack, and normal stress of the interface is generated The calculation formula of (2) is as follows: ; in the formula, The normal stress of the interface is represented by A, the bonding area of the interface is represented by the calculation formula , The bonding interface area of the left side of the concrete test piece, The bonding interface area of the right side of the concrete test piece is set; S93, fitting a constitutive model of the interlayer interface in the direction obtained by measuring mechanical parameters of the interlayer interface of the ballastless track, wherein the constitutive model comprises linear fitting of an ascending section and exponential fitting of a descending section, a normal cohesive force model diagram of the interlayer interface of the ballastless track is obtained, and the normal stress of the interlayer interface is obtained by gradually loading the normal cohesive force model diagram to the interface for damage A relationship curve; S94, the interlayer interface fracture energy is adopted to represent the energy consumed by the interlayer interface in the process of unsetting in unit area, the energy is correspondingly the area of a stress-displacement curve and an abscissa envelope, and the calculation formula is as follows: ; in the formula, Representing the normal fracture energy of the interface between layers.
6. The test method for measuring normal mechanical parameters of an interface between ballastless tracks according to claim 5, wherein in the step S93, the ascending section is When the normal stress does not reach the normal strength of the interface Interfacial normal stiffness Expressed as: ; when the normal stress reaches the interface strength After that, as the interface displacement increases, the interlayer interface starts to be damaged, and enters a descending section, and in the descending section, the normal stress of the interface is expressed as: ; Wherein D is a damage factor, 0< D <1, and the calculation formula is as follows: 。

Description

Assembled test device and test method for measuring normal mechanical parameters of interface between ballastless track layers Technical Field The invention relates to the technical field of ballastless track interface mechanics, in particular to an assembly type test device and a test method for measuring normal mechanical parameters of an interface between ballastless tracks. Background By the end of 2024 years, the business mileage of China high-speed railway reaches 4.8 kilometers, which accounts for more than 70% of the total mileage of the world high-speed railway, and the China high-speed railway is the country with the longest business operation mileage, the highest business operation speed, the most complete technical system and the most abundant application scene. The slab ballastless track is widely applied to high-speed railway construction due to the advantages of high stability, excellent smoothness, low maintenance cost and the like. Ballastless track structures generally comprise multilayer structures such as prefabricated track slabs, cement emulsified asphalt mortar (CA mortar) filling layers, concrete supporting layers or base plates, and the like, wherein the material properties of each layer are obviously different, and the interlayer mechanical behaviors are complex. The reliable bonding between the structural layers of the ballastless track plays a vital role in the aspects of service performance, durability, stability and the like of the ballastless track bed of the high-speed railway. However, under the repeated coupling actions of environmental factors such as temperature, humidity and the like and train dynamic load, performance degradation easily occurs at an interlayer interface, the contact state is changed, periodic irregularity of a track plate is caused, driving comfort and safety are seriously affected, and wheel-rail power interaction is aggravated. At present, the ballastless track in China enters a large-scale operation and maintenance stage, and along with the accumulation of operation time, diseases such as interlayer gaps and the like frequently occur, the characteristics of mass-occurrence, burstiness, repeatability and the like are presented. Therefore, the mechanical properties between ballastless track layers are accurately obtained, the interface damage behavior is evaluated, and the method has important significance in guaranteeing high smoothness, high stability and high safety of a high-speed railway. In the prior art, as disclosed in patent CN114593989B, an assembled measuring device and method are disclosed, and the solution has the advantages of assembling, but the test relies on the first/second fixing device lifting platform to perform manual leveling, and the adjusting mode is complex in operation and difficult to ensure the absolute alignment of the test piece and the bottom plate. More importantly, patent CN114593989B only obtained the original force-displacement relationship curve, lacking a reliable constitutive model for experimental data fitting. In the prior art, patent CN114839053B discloses a method for detecting interlayer interface damage, and the mechanical parameters of the interlayer interface are obtained through an interface splitting and shearing test. However, the test method adopted by the patent is different from the normal stress form born by the actual rail layer under the action of train load and temperature, so that the interlayer mechanical property of the interface in the service state is difficult to determine and truly reflect. Therefore, in order to accurately obtain the normal mechanical parameters of the interlayer interface of the ballastless track and provide reliable input for numerical simulation, development of a test device and a test method which are simple and convenient to operate and accurate in measurement is needed. Disclosure of Invention The invention provides an assembled test device and a test method for measuring normal mechanical parameters of an interface between ballastless tracks, which are compact in structure, convenient to install and test, and capable of being matched with a simple and reliable measuring and calculating method for obtaining a normal force-displacement relation curve and key normal cohesive force parameters of the interface between ballastless tracks, and providing theoretical basis and data support for numerical simulation and damage analysis of the interface between ballastless tracks, so that the obtained parameters can be directly used for simulation analysis of the normal mechanical properties of the interface between ballastless tracks, and the problems in the background art are solved. The device comprises a pushing test piece and a measuring platform, wherein a left fixing device and a right fixing device for fixing the pushing test piece are arranged in the center of the measuring platform, the pushing test piece comprises an upper concrete test piece and a lower concrete te