Dynamic monitoring system and method for subway ballast bed stripping model test

Abstract

The invention discloses a dynamic monitoring system and method for a subway ballast bed stripping model test. The dynamic monitoring system comprises an exciting force measuring device, a contact surface tension measuring device, a displacement measuring device and a strain measuring device, and the exciting force measuring device measures exciting force through a vibration exciter and a tension and pressure sensor. The contact surface tension measuring device realizes tension measurement of a track bed-segment contact surface position through a cross beam type mechanical force measuring device and a fixed steel wire. The displacement measurement device achieves displacement measurement of a duct piece structure, displacement measurement of a ballast bed structure and ballast bed stripping deformation measurement through a springback type differential variable pressure displacement sensor, a duct piece displacement measurement platform and a ballast bed displacement measurement platform. The strain measurement device achieves ballast bed-duct piece contact surface strain measurement through strain gauges arranged on the duct piece structure. According to the invention, dynamic monitoring of various data in a ballast bed stripping model test can be realized, and effective data support can be provided for ballast bed stripping disease mechanism research.

Description

Technical Field

[0001] The present invention relates to a dynamic monitoring system for subway roadbed stripping model test, mainly used for dynamic monitoring in subway tunnel model test. The present invention also relates to a data measurement method in subway roadbed stripping model test using the above dynamic monitoring system. Background Art

[0002] Under the long-term action of train loads, the roadbed structure and shield segment structure of the subway tunnel are no longer tightly connected, resulting in cracks. As the operation time increases, the cracks gradually expand, resulting in the stripping of the roadbed and the segment, affecting the safety of train operation. To solve this problem, it is necessary to study the mechanism of roadbed stripping. At present, the monitoring of roadbed stripping is carried out by entering the tunnel during the skylight time, and the development status and distribution of the disease are understood through manual measurement methods such as on-site core sampling and thickness gauge measurement of crack width. However, during the operation of subway trains, personnel are prohibited from entering the subway section for measurement, resulting in the inability to achieve real-time dynamic monitoring of the disease. Stripping usually develops under the repeated action of train dynamic loads, and the data obtained by skylight time measurement cannot reflect the most unfavorable state. Only the data measured when the train passes can best reflect the true situation of the disease. Given that the location of roadbed stripping is hidden, it is impossible to conduct research on site to ensure the safety of subway operation. Therefore, it is necessary to use model test methods to study the mechanism of the stripping problem. Model testing is an effective method for studying the mechanism of engineering problems. By scaling the main features of real engineering problems according to appropriate proportions and conducting research, the authenticity of the test results can be guaranteed.

[0003] Since subway roadbed stripping disease is a problem that has begun to appear in recent years, there is currently little research on model tests of stripping disease, and research on dynamic monitoring systems in model tests is even more insufficient, which cannot effectively provide data support for mechanism research. Summary of the invention

[0004] The object of the present invention is to provide a dynamic monitoring system for a subway roadbed stripping model test, by which dynamic monitoring of various data in the roadbed stripping model test can be achieved.

[0005] The present invention is realized by the following technical scheme: a dynamic monitoring system for subway track bed peeling model test, the test model includes a segment structure and a track bed structure made according to a similarity ratio, the track bed structure is fixed on the segment structure, and its characteristics are: the dynamic monitoring system includes an exciting force measuring device, a contact surface tension measuring device, a displacement measuring device, and a strain measuring device, the exciting force measuring device includes an exciter, a first reaction force bracket, and a tension and pressure sensor, the first reaction force bracket is a door structure, the horizontal section of the first reaction force bracket is parallel to the axis of the segment structure and passes through the segment structure, and the two columns of the first reaction force bracket are fixed On the outside of the test model, the exciter is fixed at the lower part of the horizontal section of the first reaction support, the tension and pressure sensor is fixed at the lower end of the exciter, the tension and pressure sensor is in contact with the surface of the ballast structure, the contact surface tension measuring device includes a crossbeam type mechanical force measuring device, a segment pre-embedded point, and a fixed steel wire, the crossbeam type mechanical force measuring device includes a crossbeam, a pressure sensor connected to the lower part of both ends of the crossbeam, and an adjustable screw threaded on the crossbeam, the crossbeam type mechanical force measuring device is fixed on the surface of the ballast structure, the segment pre-embedded point corresponds to the crossbeam type mechanical force measuring device pre-embedded on the outer wall of the segment structure, one end of the fixed steel wire is fixed to the segment pre-embedded point The other end of the fixed steel wire passes through the ballast structure and is fixedly connected with the adjustable screw of the beam-type mechanical force measuring device. The displacement measuring device includes a rebound differential transformer displacement sensor, a pipe segment displacement measuring platform, and a ballast displacement measuring platform. The pipe segment displacement measuring platform and the ballast displacement measuring platform are respectively arranged on both sides of the ballast structure. A first fixing rod is fixed at the bottom of the ballast displacement measuring platform. The lower end of the first fixing rod is fixed inside the ballast structure. The rebound differential transformer displacement sensor is correspondingly arranged at the upper part of the ballast displacement measuring platform and is fixed on the second reaction force bracket. The bottom of the pipe segment displacement measuring platform is fixed. A second fixing rod is provided, and the lower end of the second fixing rod is fixed inside the segment structure after passing through the through hole on the ballast structure. The rebound type differential transformer displacement sensor is also correspondingly arranged on the upper part of the segment displacement measurement platform, which is fixed on the third reaction force bracket. The second reaction force bracket and the third reaction force bracket are both door-type structures. The horizontal sections of the second reaction force bracket and the third reaction force bracket are parallel to the axis of the segment structure and pass through the segment structure. The columns of the second reaction force bracket and the third reaction force bracket are fixed on the outside of the test model. The strain measurement device includes a plurality of strain gauges, and the strain gauges are arranged on the inner wall of the segment structure along the circumferential direction of the segment structure.

[0006] In the present invention, the exciter in the excitation force measuring device can simulate the effect of the vibration load of the subway train by the excitation force generated, and the excitation force of the exciter can be monitored in real time by the tension and pressure sensor arranged at the lower end of the exciter; in the contact surface tension measuring device, one end of the fixed steel wire is connected to the pre-buried point of the pipe segment, and the other end is connected to the adjustable screw of the beam-type mechanical force measuring device fixed on the ballast structure, that is, the ballast structure and the pipe segment structure are connected by the steel wire, so the tensile stress can be transmitted through the steel wire, and the contact surface between the ballast and the pipe segment structure is realized by the pressure sensor of the beam-type mechanical force measuring device. Measurement of position tension; in the displacement measuring device, the segment displacement measuring platform and the ballast bed displacement measuring platform are connected to the segment structure and the ballast bed structure respectively through fixed rods, and the probes of the corresponding rebound differential transformer displacement sensor can be in contact with the segment displacement measuring platform and the ballast bed displacement measuring platform respectively, and the displacement of the segment structure and the displacement of the ballast bed structure can be measured respectively through the corresponding rebound differential transformer displacement sensor, and the ballast bed peeling deformation can be obtained by calculating the displacement deformation difference between the ballast bed structure and the segment structure; in the strain measuring device, the strain amount of the ballast bed-segment contact surface is measured by a strain gauge.

[0007] Furthermore, three rows of the beam-type mechanical force measuring devices are arranged on the surface of the ballast structure near the expansion joint, and each row is provided with 5 beam-type mechanical force measuring devices.

[0008] Furthermore, the first fixing rod is fixed at a position 10 mm inside the ballast structure; and the second fixing rod is fixed at a position 10 mm inside the segment structure.

[0009] Furthermore, three rows of the displacement measuring devices are arranged on the surface of the ballast structure near the expansion joint.

[0010] The present invention also provides a method for measuring data in a subway ballast stripping model test, and the technical solution adopted is: using the above-mentioned dynamic monitoring system to measure various data in the test, the measured data include the measurement of exciting force, the measurement of tension on the ballast-segment contact surface, the measurement of displacement, and the measurement of strain; the exciting force of the exciter is measured by the tension and pressure sensor of the exciting force measuring device, the tension at the ballast-segment contact surface position is measured by the contact surface tension measuring device, the displacement of the segment structure and the displacement of the ballast structure are respectively measured by the rebound differential transformer displacement sensor in the displacement measuring device, the ballast stripping deformation is obtained by calculating the displacement deformation difference between the ballast structure and the segment structure, and the ballast-segment contact surface strain is measured by the strain measuring device.

[0011] The beneficial effects of the present invention are as follows: currently, there are few studies on the model test of ballast bed peeling disease, among which there is no monitoring system for the model test of ballast bed peeling. The present invention proposes for the first time a dynamic monitoring system and method for the model test of subway ballast bed peeling, which can realize the dynamic monitoring of various data in the model test of ballast bed peeling, and can provide effective data support for the study of the mechanism of ballast bed peeling disease; since the location of ballast bed peeling is hidden, the peeling is located at the contact surface between the ballast bed and the pipe segment structure, and conventional methods cannot be directly measured, the peeling location for the model test is more hidden, and the measurement is more difficult. In view of this problem, the present invention By using a specially designed segment displacement measuring platform and ballast bed displacement measuring platform and a rebound differential transformer displacement sensor, dynamic measurement of ballast bed displacement and segment displacement is completed, and the stripping amount value is calculated based on this, thereby realizing dynamic measurement of ballast bed stripping, and solving the problem that the ballast bed stripping amount is difficult to measure in the prior art; the present invention adopts a beam-type force measuring device and uses a fixed steel wire to connect the segment structure and the adjustable screw connection of the beam-type force measuring device to realize dynamic measurement of the tension at the contact surface of the ballast bed-segment structure in the model test, which is convenient for comprehensive analysis of the stress conditions and provides data support for the analysis of the disease mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a three-dimensional structural schematic diagram of a monitoring system for a subway roadbed stripping model test in the present invention;

[0013] Figure 2 It is a cross-sectional schematic diagram of a monitoring system for a subway ballast stripping model test in the present invention;

[0014] Figure 3 It is a cross-sectional schematic diagram of a monitoring system for a subway roadbed stripping model test in the present invention;

[0015] Figure 4 yes Figure 3 An enlarged schematic diagram of the lower middle part;

[0016] Figure 5 It is a front view schematic diagram of the crossbeam type mechanical force measuring device in the present invention;

[0017] Figure 6 1 is a top view schematic diagram of the crossbeam type mechanical force measuring device in the present invention (the adjustable screw is not shown);

[0018] Figure 7 It is a schematic diagram of the connection between the contact surface tension measuring device and the pipe segment structure in the present invention;

[0019] Figure 8 It is a schematic diagram of the arrangement of the contact surface tension measuring device and the displacement measuring device in a specific embodiment of the present invention;

[0020] In the figure, 1, segment structure, 2, first reaction support, 3, second reaction support, 4, third reaction support, 5, ballast bed structure, 6, vibration exciter, 7, tension and pressure sensor, 8, contact surface tension measuring device, 9, expansion joint, 10, displacement measuring device, 11, strain gauge;

[0021] 8.1, beam-type mechanical force measuring device, 8.2, pre-embedded points of pipe segments, 8.3, fixing steel wire;

[0022] 8.1.1, crossbeam, 8.1.2, adjustable screw, 8.1.3, pressure sensor;

[0023] 10.1. first rebound differential transformer displacement sensor, 10.2. ballast bed displacement measuring platform, 10.3. first fixing rod, 10.4. second rebound differential transformer displacement sensor, 10.5. segment displacement measuring platform, 10.6. second fixing rod. DETAILED DESCRIPTION

[0024] The present invention will be further described below by way of non-limiting embodiments and in conjunction with the accompanying drawings:

[0025] As shown in the attached figure, a dynamic monitoring system for a subway track bed stripping model test, wherein the test model includes a segment structure 1 and a track bed structure 5 made according to a similarity ratio, and the track bed structure 5 is fixed on the segment structure 1. The dynamic monitoring system includes an exciting force measuring device, a contact surface tension measuring device 8, a displacement measuring device 10, and a strain measuring device. The exciting force measuring device includes a vibrator 6, a first reaction force bracket 2, and a tension and pressure sensor 7. The first reaction force bracket 2 is a door-type structure. The horizontal section of the first reaction force bracket 2 is parallel to the axis of the segment structure and penetrates the segment structure. The two columns of the first reaction force bracket 2 are fixed on the outside of the test model. The vibrator 6 is fixed at the lower part of the horizontal section of the first reaction force bracket 2. The tension and pressure sensor 7 is fixed at the lower end of the vibrator 6. In the unloaded state, it should be ensured that the tension and pressure sensor 7 can just contact the surface of the track bed structure. The vibrator 6 and the tension and pressure sensor 7 are both existing technologies. The selection of the vibrator 6 is selected according to the structural size and the numerical range of the exciting force. The contact surface tension measuring device 8 comprises a crossbeam type mechanical force measuring device 8.1, a segment pre-embedded point 8.2, and a fixed steel wire 8.3. The crossbeam type mechanical force measuring device 8.1 comprises a crossbeam 8.1.1, a pressure sensor 8.1.3 connected to the lower part of both ends of the crossbeam 8.1.1, and an adjustable screw 8.1.2 threadedly connected to the middle part of the crossbeam. The crossbeam type mechanical force measuring device 8.1 is fixed on the surface of the ballast structure 5. The segment pre-embedded point 8.2 corresponds to the crossbeam type mechanical force measuring device 8.1 and is pre-embedded on the outer wall of the segment structure 1. One end of the fixed steel wire 8.3 is fixedly connected to the segment pre-embedded point 8.2, and the other end of the fixed steel wire 8.3 passes through the ballast structure and is fixedly connected to the adjustable screw 8.1.2 of the crossbeam type mechanical force measuring device. Thus, the ballast structure 5 and the segment structure 1 are connected by the fixed steel wire 8.3, so the tensile stress can be transmitted by the fixed steel wire 8.3 to achieve the measurement of the tension at the contact surface of the ballast-segment structure. The pressure sensor 8.1.3 is a prior art. The pre-embedded points 8.2 of the pipe segments are embedded according to the test requirements. Preferably, three rows of the beam-type mechanical force measuring devices 8.1 are arranged on the surface of the ballast structure near the expansion joint, and each row is provided with 5 beam-type mechanical force measuring devices. The pre-embedded points 8.2 of the pipe segments are correspondingly arranged on the pipe segment structure 1.The displacement measuring device 10 includes a ballast bed displacement measuring device and a segment displacement measuring device. The ballast bed displacement measuring device includes a first rebound differential transformer displacement sensor 10.1 and a ballast bed displacement measuring platform 10.2. The segment displacement measuring device includes a second rebound differential transformer displacement sensor 10.4 and a segment displacement measuring platform 10.5. The segment displacement measuring platform 10.5 and the ballast bed displacement measuring platform 10.2 are respectively arranged on both sides of the ballast bed structure 5. A first fixing rod 10.3 is fixed to the bottom of the ballast bed displacement measuring platform 10.2. The lower end of the fixed rod 10.3 is fixed inside the ballast structure 5, the first rebound differential transformer displacement sensor 10.1 is correspondingly arranged on the upper part of the ballast displacement measurement platform 10.2 and fixed on the second reaction support 3, the bottom of the segment displacement measurement platform 10.5 is fixed with a second fixed rod 10.6, the lower end of the second fixed rod 10.6 passes through the through hole on the ballast structure 5 and is fixed inside the segment structure 5, and the second rebound differential transformer displacement sensor 10.4 is correspondingly arranged on the upper part of the segment displacement measurement platform 10.5 and fixed on the third reaction support 4. The second reaction support 3 and the third reaction support 4 are both gate structures, the horizontal sections of the second reaction support 3 and the third reaction support 4 are parallel to the axis of the segment structure and penetrate the segment structure, and the columns of the second reaction support 3 and the third reaction support 4 are fixed on the outside of the test model. The ballast bed displacement measurement platform 10.2 and the segment displacement measurement platform 10.5 are used to contact the probes of the first rebound differential transformer displacement sensor 10.1 and the second rebound differential transformer displacement sensor 10.4 respectively. The model of the rebound differential transformer displacement sensor is determined according to the specific size of the model test, and the range and measurement accuracy can be selected according to the structural size. The rebound differential transformer displacement sensor is a prior art. The displacement of the segment structure and the displacement of the ballast bed structure can be measured respectively by the first rebound differential transformer displacement sensor 10.1 and the second rebound differential transformer displacement sensor 10.4, and the measurement of the ballast bed peeling deformation is obtained by calculating the displacement deformation difference between the ballast bed and the segment. In order to ensure the reliability of the test data, it is preferred that the first fixing rod 10.3 is fixed at a position of 10 mm inside the ballast bed structure; the second fixing rod 10.6 is fixed at a position of 10 mm inside the segment structure. The layout of the displacement measuring device 10 is arranged according to the test requirements. Preferably, three rows of displacement measuring devices are arranged on the surface of the ballast structure near the expansion joint. The strain measuring device includes a plurality of strain gauges 11, which are arranged on the inner wall of the pipe segment structure along the circumferential direction. The strain gauges 11 are prior art. After the arrangement of each measuring device is completed, the data line is connected to the corresponding sensor, and then the data line is connected to the data acquisition device, and finally connected to the external computer terminal, and the data of multiple sets of sensors are synchronously collected through special software.

[0026] A method for measuring data in a subway ballast stripping model test, using the above-mentioned dynamic monitoring system to measure various data in the test, the measured data including the measurement of exciting force, the measurement of tension on the ballast-segment contact surface, the measurement of displacement, and the measurement of strain, the exciting force of the vibrator is measured by the tension-pressure sensor of the exciting force measuring device, the tension at the ballast-segment contact surface is measured by the contact surface tension measuring device, the displacement of the segment structure and the displacement of the ballast structure are respectively measured by the rebound differential transformer displacement sensor in the displacement measuring device, the ballast stripping deformation is obtained by calculating the displacement deformation difference between the ballast structure and the segment structure, and the ballast-segment contact surface strain is measured by the strain measuring device.

[0027] The present invention is specifically described below by specific embodiments:

[0028] Example:

[0029] The model test was set up according to a 10:1 similarity ratio. The test device corresponds to a 30m long on-site tunnel, including 20 rings of segments, 2 12m ballasts, and 2 3m ballasts. The inner diameter of the subway tunnel is 5.4m and the outer diameter is 6.0m; the tunnel segment width is 1.5m and the thickness is 0.3m; the length of a complete ballast section of the tunnel is 12m and the width is 2.8m. The excitation force of a conventional subway train is 105kN.

[0030] 1. According to the geometric similarity ratio of 10:1, determine the size of each component of the model. In the model, the inner diameter of the segment is 540mm, the outer diameter is 600mm, the thickness is 30mm, the width is 150mm, and there are 30 rings of segments in total; the 1# and 4# ballasts at both ends are 300mm long, and the 2# and 3# ballasts in the middle are 1200mm long and 280mm wide, and there are 4 ballasts in total.

[0031] 2. According to the similarity ratio, the excitation force load in the model test is 105N, and the inner diameter of the subway tunnel segment is 540mm. Based on this, the specific parameters such as the size and amplitude of the exciter are determined as follows: the exciter model is SA-JZ020, the maximum excitation force provided is 200N, the maximum amplitude is 10mm, the loading frequency range that can be provided is 0-4000Hz, the deadweight is 19kg, and the outer dimensions are a cylinder of φ180mm*245mm. The tension and pressure sensor is selected as: tension and compression piezoelectric sensor measurement, model SACL201LX, range is 0-200N, and the error is controlled within 1%. The tension and pressure sensor is installed at the lower end of the exciter, and the load data of the exciter can be transmitted in real time.

[0032] 3. Exciting force measurement: The exciter 6 is arranged on the horizontal section of the first reaction support 2. The position is adjusted to ensure that the center of the exciter 6 coincides with the center of the first reaction support 2. The tension and pressure sensor 7 is fixed at the lower end of the exciter 6. In the unloaded state, it should be ensured that the tension and pressure sensor 7 can just contact the surface of the ballast structure. The exciting force measurement is achieved through the tension and pressure sensor 7.

[0033] 4. Contact surface tension measurement: It is achieved through the contact surface tension measurement device, and the tension measurement is completed through the combination of pressure sensor and beam structure.

[0034] 4.1 The pressure sensor adopts a high-precision miniature resistance strain sensor with a measuring range of 0-5kg and an accuracy of 0.1%. The tension and pressure values ​​are output through the matching acquisition card and acquisition software.

[0035] 4.2 The pre-embedded points 8.2 of the segment are embedded in the segment structure according to the requirements, and the corresponding beam-type mechanical force measuring device 8.1 is fixed on the surface of the ballast structure. The pre-embedded points 8.2 of the segment and the corresponding adjustable screws 8.1.2 of the beam-type mechanical force measuring device 8.1 are connected by fixing steel wires 8.3. In this embodiment, three rows of beam-type mechanical force measuring devices 8.1 are arranged within 150mm of the 2# ballast near the expansion joint, with 5 measuring points in each row, as shown in the attached figure. Figure 8 The ballast structure and the segment structure are connected by the fixed steel wire 8.3, so the tensile stress can be transmitted through the fixed steel wire to achieve the measurement of the tensile force at the contact surface of the ballast-segment structure.

[0036] 5. Displacement measurement:

[0037] 5.1 The model of the rebound differential transformer displacement sensor (LVDT sensor) is Miran LVDT20-V1-5MM, with a measuring range of 0-5mm and an accuracy of 1μm. The sensor is integrated into the 6005 acquisition card through a transmission line and then connected to the computer. Then, the data of multiple groups of sensors are synchronously collected through special software, and the data collection frequency can reach 10Hz.

[0038] 5.2 LVDT sensors are arranged on both sides of the ballast structure and fixed on the corresponding reaction force brackets respectively; a ballast displacement measuring platform is set up, the upper end of the first fixed rod is fixedly connected to the ballast displacement measuring platform, and the lower end of the first fixed rod is fixed at a position of 10mm inside the ballast structure, forming an integral part with the ballast structure; a pipe segment displacement measuring platform is set up, the upper end of the second fixed rod is fixedly connected to the pipe segment displacement measuring platform, and the lower end of the second fixed rod is fixed at a position of 10mm inside the pipe segment structure, forming an integral part with the pipe segment structure, and the second fixed rod passes through a through hole drilled on the ballast structure, and the diameter of the through hole drilled on the ballast structure should be larger than the diameter of the second fixed rod. The probe of the LVDT sensor should be in contact with the corresponding ballast displacement measuring platform and pipe segment displacement measuring platform. In this embodiment, three rows of the displacement measuring devices are arranged on the surface of the ballast structure near the expansion joint, as shown in the attached Figure 8 shown.

[0039] 6. Strain measurement:

[0040] Strain gauges are arranged along the circumferential direction of the segment structure, mainly at the first ring position of the 2# track bed. The strain gauge distribution is shown in the attached figure. Figure 2 Medium 1-1 to 1-10.

[0041] 7. After the exciting force measuring device, contact surface tension measuring device, displacement measuring device and strain measuring device are laid out, each device is connected to the data cable, the data cable is connected to the corresponding acquisition device, and the external computer is connected to collect data through the corresponding measurement software, so as to dynamically measure the exciting force, ballast-segment contact surface tension, displacement (ballast displacement, segment displacement, peeling deformation), and ballast-segment contact surface strain.

[0042] The other parts of this embodiment are all prior art and will not be described in detail here.

Claims

1. A dynamic monitoring system for a subway ballast stripping model test, wherein the test model comprises a segment structure and a ballast structure made according to a similarity ratio, and the ballast structure is fixed on the segment structure, and wherein: The dynamic monitoring system includes an exciting force measuring device, a contact surface tension measuring device, a displacement measuring device, and a strain measuring device. The exciting force measuring device includes a vibrator, a first reaction force bracket, and a tension and pressure sensor. The first reaction force bracket is a door-type structure. The horizontal section of the first reaction force bracket is parallel to the axis of the segment structure and penetrates the segment structure. The two columns of the first reaction force bracket are fixed on the outside of the test model. The vibrator is fixed at the lower part of the horizontal section of the first reaction force bracket. The tension and pressure sensor is fixed at the lower end of the vibrator. The tension and pressure sensor is in contact with the surface of the ballast bed structure. The contact surface tension measuring device comprises a crossbeam type mechanical force measuring device, a segment pre-embedded point, and a fixed steel wire. The crossbeam type mechanical force measuring device comprises a crossbeam, a pressure sensor connected to the lower part of both ends of the crossbeam, and an adjustable screw threadedly connected to the crossbeam. The crossbeam type mechanical force measuring device is fixed on the surface of the ballast structure. The segment pre-embedded point corresponds to the crossbeam type mechanical force measuring device and is pre-embedded on the outer wall of the segment structure. One end of the fixed steel wire is fixedly connected to the segment pre-embedded point, and the other end of the fixed steel wire passes through the ballast structure and is fixedly connected to the adjustable screw of the crossbeam type mechanical force measuring device. The displacement measuring device comprises a rebound differential transformer displacement sensor, a segment displacement measuring platform and a ballast bed displacement measuring platform. The segment displacement measuring platform and the ballast bed displacement measuring platform are respectively arranged on both sides of the ballast bed structure. A first fixing rod is fixed at the bottom of the ballast bed displacement measuring platform, and the lower end of the first fixing rod is fixed inside the ballast bed structure. The rebound differential transformer displacement sensor is correspondingly arranged on the upper part of the ballast bed displacement measuring platform and is fixed on the second reaction force bracket. A second fixing rod is fixed at the bottom of the segment displacement measuring platform, and the lower end of the second fixing rod passes through the through hole on the ballast bed structure and is fixed inside the segment structure. The rebound differential transformer displacement sensor is also correspondingly arranged on the upper part of the segment displacement measuring platform and is fixed on the third reaction force bracket. Both the second reaction force bracket and the third reaction force bracket are gate structures. The horizontal sections of the second reaction force bracket and the third reaction force bracket are parallel to the axis of the segment structure and penetrate the segment structure. The columns of the second reaction force bracket and the third reaction force bracket are fixed on the outer side of the test model. The strain measuring device comprises a plurality of strain gauges, and the strain gauges are arranged on the inner wall of the segment structure along the circumferential direction of the segment structure.

2. The dynamic monitoring system for subway roadbed stripping model test according to claim 1 is characterized by: Three rows of the beam-type mechanical force measuring devices are arranged on the surface of the ballast structure near the expansion joint, and each row is provided with 5 beam-type mechanical force measuring devices.

3. The dynamic monitoring system for subway roadbed stripping model test according to claim 2 is characterized by: The first fixing rod is fixed at a position 10 mm inside the ballast structure; the second fixing rod is fixed at a position 10 mm inside the segment structure.

4. The dynamic monitoring system for subway roadbed stripping model test according to claim 3 is characterized by: Three rows of displacement measuring devices are arranged on the surface of the ballast structure near the expansion joint.

5. A method for measuring data in a subway roadbed stripping model test, characterized by: The dynamic monitoring system described in any one of claims 1 to 4 is used to measure various data in the test, and the measurement data include the measurement of exciting force, the measurement of tension on the ballast bed-segment contact surface, the measurement of displacement, and the measurement of strain. The exciting force of the vibrator is measured by the tension and pressure sensor of the exciting force measuring device, the tension at the ballast bed-segment contact surface is measured by the contact surface tension measuring device, the displacement of the segment structure and the displacement of the ballast bed structure are measured respectively by the rebound differential transformer displacement sensor in the displacement measuring device, the ballast bed peeling deformation is obtained by calculating the displacement deformation difference between the ballast bed structure and the segment structure, and the ballast bed-segment contact surface strain is measured by the strain measuring device.

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