A method for evaluating a ballast contamination state

Abstract

The application discloses a ballast bed dirt state evaluation method, and relates to the field of on-site detection of ballast track. The evaluation method comprises the following steps: inserting an evaluation device with a hollow interior and a surface provided with a plurality of water-permeable holes into the interior of the ballast bed to a set depth; making the water-permeable holes on the surface of the evaluation device in a closed state, and injecting water into the interior of the evaluation device to an initial water level height; opening the water-permeable holes on the surface of the evaluation device, and recording the time consumption for the water level in the interior of the evaluation device to drop to a set water level height; calculating a permeation coefficient; and evaluating the ballast bed dirt rate based on the permeation coefficient. The application provides a ballast bed dirt state evaluation method, so as to solve the problems that the detection means for the ballast bed dirt degree in the prior art is strong in destructiveness, low in efficiency, and highly dependent on the environment and operators, and achieve the purpose of quickly and conveniently detecting the ballast bed dirt degree on site.

Description

Technical Field

[0001] This invention relates to the field of on-site inspection of ballasted tracks, and more specifically to a method for assessing the dirt and grime status of the track bed. Background Technology

[0002] Ballasted track, as the most widely used railway track type worldwide, is widely applied in various scenarios such as high-speed railways, conventional railways, heavy-haul transport lines, and urban rail transit due to its advantages such as high structural flexibility, good vibration reduction capacity, convenient maintenance, and low construction cost. In the development of my country's railways, ballasted track continues to play an important role in the construction and expansion of new lines, especially in mountainous areas with complex terrain, high construction difficulty, and varied geological conditions, where its excellent adaptability makes it the preferred structural form.

[0003] During long-term operation, the ballast track bed structure inevitably suffers from particle breakage, fine particle accumulation, and gradation deterioration due to repeated train loads, tamping and maintenance operations by large machinery, and environmental factors. This leads to increased dirtiness of the ballast bed, loss of the original interlocking relationship between ballast particles, and a gradual decline in the load-bearing capacity and drainage performance of the ballast bed, ultimately affecting the stability and safety of the track geometry.

[0004] Therefore, obtaining the degree of track bed contamination quickly, objectively, and repeatedly is a crucial preliminary step in understanding the current condition of the track bed and formulating a cleaning and screening plan. Existing detection methods mainly include: 1. Sampling and sieving method: Samples are taken from the track bed sleeper box and sieved on-site or sent to an indoor laboratory for sieving. The contamination rate of the track bed sample is calculated based on particle size classification. This method can accurately obtain the contamination status of the track bed, but it is highly destructive, has poor representativeness, high labor and time costs, and low efficiency. 2. Non-destructive testing methods such as ground-penetrating radar (GPR): These methods can achieve continuous scanning, but the signal is affected by moisture content, rail / fastener reflection, and multi-layered media scattering, resulting in large errors when the sample size is small. Extensive on-site calibration is required to accurately infer the contamination rate from physical quantities.

[0005] In summary, existing technologies for detecting the degree of dirtiness in track beds have drawbacks such as being highly destructive, inefficient, and heavily dependent on the environment and operators. Summary of the Invention

[0006] This invention provides a method for assessing the dirt and grime status of track beds, which solves the problems of existing methods for detecting the degree of dirt and grime in track beds being highly destructive, inefficient, and dependent on the environment and operators, and achieves the goal of quickly and conveniently conducting on-site detection of the degree of dirt and grime in track beds.

[0007] This invention is achieved through the following technical solution:

[0008] A method for assessing the dirt and grime status of a track bed includes the following steps:

[0009] S1. Insert the evaluation device, which is hollow inside and has several water-permeable holes on the surface, into the track bed to a set depth;

[0010] S2. Close the water holes on the surface of the evaluation device and fill the evaluation device with water to the initial water level.

[0011] S3. Open the water-permeable holes on the surface of the evaluation device and record the time it takes for the water level inside the evaluation device to drop to the set water level height.

[0012] S4. Calculate the permeability coefficient;

[0013] S5. Evaluate the dirtiness rate of the track bed based on the permeability coefficient.

[0014] To address the problems of existing methods for detecting track bed contamination, such as high destructiveness, low efficiency, and heavy reliance on the environment and operators, this invention proposes a method for assessing track bed contamination status. This method first prepares an assessment device with a hollow interior and several permeable holes on its surface, which can be opened and closed as needed. In execution, the assessment device is first inserted into the track bed to a set depth, with the permeable holes closed, and water is injected to bring the liquid level to an initial height. Then, the permeable holes are opened, allowing water to seep into the track bed through them, gradually lowering the water level. The time taken for the water level to drop to the set height is recorded. Based on the head change and time taken for the water level to drop from the initial height to the set height, the permeability coefficient of the track bed can be calculated, thereby assessing the track bed contamination rate.

[0015] This application overcomes the shortcomings of the sampling and sieving method in the prior art, which is highly destructive, inefficient, and has high labor and time costs. It also overcomes the problems of the non-destructive testing method in the prior art, which is highly dependent on the environment and operators and requires a large number of samples for calibration. It achieves the effect of rapid and convenient on-site assessment of the dirt level of the track bed.

[0016] Furthermore, the permeability coefficient is calculated using the following formula:

[0017] ;

[0018] Where: K est I is the permeability coefficient; L is the permeability efficiency; e Equivalent seepage path; H avg C represents the average head height. T This is the water temperature viscosity correction factor.

[0019] Those skilled in the art will understand that the water temperature and viscosity correction factor C is...T It is only related to water temperature; as long as the water temperature at the time of evaluation is measured, the viscosity can be calculated by looking up a table or using an empirical formula, and then the corresponding water temperature viscosity correction coefficient can be obtained.

[0020] Furthermore, the penetration efficiency is calculated using the following formula:

[0021] ;

[0022] In the formula: A is the cross-sectional area inside the evaluation device; S is the total orifice area of ​​the permeable holes on the surface of the evaluation device; h1 is the initial water level height; h2 is the set water level height; t is the time it takes for the water level inside the evaluation device to drop to the set water level height.

[0023] Furthermore, the equivalent seepage path is equal to the axial length of the permeable hole, which can also be understood as the wall thickness of the evaluation device.

[0024] Furthermore, the average head height is calculated using the following formula:

[0025] ;

[0026] In the formula: h1 is the initial water level; h2 is the set water level.

[0027] Furthermore, the method for assessing the track bed fouling rate based on the permeability coefficient includes calculating the track bed fouling rate evaluation index using the following formula:

[0028] ;

[0029] In the formula: FI is the evaluation index of track bed dirt rate; K est0 γ is the baseline value for the permeability coefficient; γ is the regression correction coefficient.

[0030] The track bed dirtiness rate evaluation index FI can effectively characterize the dirtiness of the track bed, which is conducive to quickly judging the dirtiness of the track bed on site.

[0031] Furthermore, the permeability coefficient benchmark value K est0 Obtained through the following method:

[0032] Construct a clean ballast track bed model box indoors;

[0033] The evaluation device is inserted into the ballast bed model box of the clean ballast to a set depth;

[0034] Perform steps S2 to S4, and use the calculated permeability coefficient as the reference value of the permeability coefficient.

[0035] Furthermore, the regression correction coefficients are obtained using the following method:

[0036] Prepare several ballast particles with different dirt levels, and construct several track bed model boxes with different dirt levels indoors.

[0037] The evaluation device was inserted into several track bed model boxes with different dirt rates to a set depth.

[0038] Perform steps S2 to S4 to obtain the permeability coefficients corresponding to different dirt levels;

[0039] A model relating the permeability coefficient and the regression correction coefficient is established, and the regression correction coefficient is obtained by regression analysis.

[0040] The regression solution method can be implemented using any existing regression algorithm as needed, and no specific restrictions are imposed here.

[0041] Furthermore, the evaluation device includes an outer tube closed at the bottom and an inner tube rotatably fitted inside the outer tube. The outer tube has a plurality of first water-permeable holes on its side wall, and the inner tube has a plurality of second water-permeable holes on its side wall. The inner tube has a first working position and a second working position for rotational adjustment.

[0042] When the inner tube is in the first working position, the second water-permeable hole is connected to the first water-permeable hole;

[0043] When the inner tube is in the second working position, the second water-permeable hole is not connected to the first water-permeable hole.

[0044] This design defines the specific structure of the evaluation device. The inner tube is located inside the outer tube and is capable of relative rotation with the outer tube. The inner tube can rotate to a first position and a second position: when the inner tube is in the second position, water inside the inner tube cannot seep out of the outer tube; when the inner tube is in the first position, water inside the inner tube can enter the first water-permeable hole through the second water-permeable hole and then seep out of the outer tube. Therefore, in this design, the water injection space inside the evaluation device is the internal space of the inner tube.

[0045] In practical use, the evaluation device of this scheme is initially in the second working position of the inner tube; the evaluation device is inserted into the track bed to the set depth through the outer tube, and water is injected into the inner tube; the inner tube is rotated to the first working position, so that the second water permeable hole is connected to the first water permeable hole, and the water level inside the inner tube begins to drop, and the time required for the water level to drop from the initial water level height to the set water level height is recorded.

[0046] Furthermore, the evaluation device also includes a monitoring component for monitoring the water level inside the inner tube. By monitoring the liquid level inside the inner tube, the monitoring component provides effective support for monitoring changes in the liquid level during the evaluation process. The monitoring component can be implemented automatically using various liquid level sensors, or it can be implemented using a viewing window or other methods that facilitate manual monitoring.

[0047] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0048] 1. The present invention provides a method for assessing the dirt and grime status of roadbeds, which overcomes the shortcomings of the sampling and sieving method in the prior art, such as strong destructiveness, low efficiency, and high labor and time costs. It also overcomes the problems of the non-destructive testing method in the prior art, such as high dependence on the environment and operators and the need for a large number of samples for calibration. The invention achieves the effect of rapid and convenient on-site assessment of the dirt and grime level of roadbeds.

[0049] 2. The present invention provides a method for assessing the dirt and grime status of a track bed. The dirt and grime rate evaluation index FI can effectively characterize the dirt and grime status of the track bed, which is conducive to quickly judging the dirt and grime status of the track bed on site, and thus provides a scientific basis for understanding the current status of the track bed and formulating cleaning and screening plans. Attached Figure Description

[0050] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0051] Figure 1 This is a flowchart illustrating a specific embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of the evaluation device when the inner tube is in the second working position in a specific embodiment of the present invention;

[0053] Figure 3 This is a cross-sectional view of the evaluation device when the inner tube is in the second working position in a specific embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the evaluation device when the inner tube is in the first working position in a specific embodiment of the present invention;

[0055] Figure 5 This is a cross-sectional view of the evaluation device when the inner tube is in the first working position in a specific embodiment of the present invention;

[0056] Figure 6 This is a working elevation view of the evaluation device in a specific embodiment of the present invention;

[0057] Figure 7 This is a top view of the evaluation device in operation in a specific embodiment of the present invention.

[0058] The attached diagram shows the markings and corresponding component names:

[0059] 1-Outer tube, 2-Inner tube, 3-First water-permeable hole, 4-Second water-permeable hole, 5-Cover, 6-Transparent window, 7-Scale line, 8-First handle, 9-Circumferential groove, 10-Axial groove, 11-Second handle, 12-Conical part, 13-Railway bed, 14-Sleeper, 15-Rail. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explaining the invention only and are not intended to limit the invention. In the description of this application, it should be understood that terms such as "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "high," "low," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They 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 limiting the scope of protection of this application.

[0061] Example 1:

[0062] like Figure 1 The method for assessing the dirt and grime status of a track bed, as shown, includes the following steps:

[0063] Step S1: Insert the evaluation device, which is hollow inside and has several water-permeable holes on its surface, into the track bed to a set depth. In this embodiment, the set depth is 35cm below the sleeper; that is, all the water-permeable holes are located between the bottom surface of the sleeper and a depth of 35cm below the sleeper.

[0064] Step S2: Close the water holes on the surface of the evaluation device and fill the evaluation device with water to the initial water level.

[0065] Step S3: Open the water-permeable holes on the surface of the evaluation device and record the time it takes for the water level inside the evaluation device to drop to the set water level height.

[0066] Step S4: Calculate the permeability coefficient:

[0067] ;

[0068] Where: K est I is the permeability coefficient; L is the permeability efficiency; e Equivalent seepage path; H avg C represents the average head height. T This is the water temperature viscosity correction factor.

[0069] Wherein, the equivalent seepage path L eIt is equal to the length of the permeable hole along its own axial direction.

[0070] The permeability I is calculated using the following formula:

[0071] ;

[0072] In the formula: A is the cross-sectional area inside the evaluation device; S is the total orifice area of ​​the permeable holes on the surface of the evaluation device; h1 is the initial water level height; h2 is the set water level height; t is the time it takes for the water level inside the evaluation device to drop to the set water level height.

[0073] Among them, the average head height H avg Calculated using the following formula:

[0074] ;

[0075] In the formula: h1 is the initial water level; h2 is the set water level.

[0076] Step S5: Assess the track bed fouling rate based on the permeability coefficient. This embodiment calculates the track bed fouling rate evaluation index using the following formula:

[0077] ;

[0078] In the formula: FI is the evaluation index of track bed dirt rate; K est0 γ is the baseline value for the permeability coefficient; γ is the regression correction coefficient.

[0079] Wherein, the permeability coefficient reference value K est0 Obtained through the following method:

[0080] Construct a clean ballast track bed model box indoors;

[0081] The evaluation device is inserted into the ballast bed model box of the clean ballast to a set depth;

[0082] Perform steps S2 to S4, and use the calculated permeability coefficient as the reference value K for the permeability coefficient. est0 .

[0083] The regression correction coefficients are obtained using the following method:

[0084] Prepare several ballast particles with different dirt rates (different fine material ratios) and construct several ballast bed model boxes with different dirt rates indoors.

[0085] The evaluation device was inserted into several track bed model boxes with different dirt rates to a set depth.

[0086] Perform steps S2 to S4 to obtain the permeability coefficients corresponding to different dirt levels;

[0087] Establish a model relating the permeability coefficient and the regression correction coefficient, solve the regression problem, and obtain the regression correction coefficient.

[0088] Verify the regression results.

[0089] In this embodiment, the relationship model between the permeability coefficient and the regression correction coefficient can be implemented using the calculation formula for the track bed fouling rate evaluation index mentioned above. During the regression solution process, the track bed fouling rate evaluation index FI is taken as a known fouling rate, and K... est0 Since this is also known, the regression correction coefficient γ can be obtained through a regression algorithm.

[0090] In this embodiment, the regression solution process is completed using the least squares method or a nonlinear fitting algorithm (such as Levenberg–Marquardt).

[0091] In this embodiment, the method for verifying the regression results includes:

[0092] After obtaining the regression correction coefficient γ, the goodness of fit is evaluated.

[0093] Analyze the residual distribution to ensure that the model has not deviated systematically.

[0094] In a more preferred embodiment, during the process of obtaining the regression correction coefficients, ballast particles corresponding to different contamination materials are prepared based on the actual contamination material of the track bed being evaluated. For example, for coal transport track, the main contaminant is coal ash, so coal ash is also used as the main contamination material when preparing ballast particles.

[0095] Example 2:

[0096] A method for assessing the dirt and grime status of a track bed is provided. Based on Example 1, this example provides an assessment device specifically designed for assessing the dirt and grime status of a track bed, used to perform the assessment method described in Example 1.

[0097] The evaluation device, such as Figures 2 to 7 As shown, it includes an outer tube 1 with its bottom closed and an inner tube 2 that is rotatably fitted inside the outer tube 1. The outer tube 1 has a plurality of first water-permeable holes 3 on its side wall and the inner tube 2 has a plurality of second water-permeable holes 4 on its side wall. The inner tube 2 has a first working position and a second working position for rotational adjustment.

[0098] When inner tube 2 is in the second working position, such as Figure 1 and Figure 2 As shown, the second permeable hole 4 is not connected to the first permeable hole 3;

[0099] When inner tube 2 is in the first working position, such as Figure 3 and Figure 4 As shown, the second permeable hole 4 is connected to the first permeable hole 3.

[0100] In this embodiment, the second water-permeable hole 4 corresponds one-to-one with the first water-permeable hole 3; when the inner tube 2 is in the first working position, each second water-permeable hole 4 is directly opposite a first water-permeable hole 3; when the inner tube 2 is in the second working position, each second water-permeable hole 4 is misaligned with the first water-permeable hole 3.

[0101] In this embodiment, the bottom of the inner tube 2 is closed, and the top of the inner tube 2 is detachably connected to the cover 5.

[0102] This embodiment also includes a monitoring component for monitoring the water level inside the inner pipe 2. This monitoring component can be implemented using automatic or manual monitoring methods.

[0103] When automatic monitoring is used, a liquid level sensor can be installed inside the inner tube.

[0104] When manual monitoring is used:

[0105] The inner tube 2 is made of transparent material; the outer tube 1 has a transparent window 6 extending axially on its side wall, and scale lines 7 are provided at the transparent window 6. All the first water-permeable holes 3 are located below the transparent window 6.

[0106] In this embodiment, the diameter of the first water-permeable hole 3 and the second water-permeable hole 4 is 0.5~2mm.

[0107] In a more preferred embodiment, the outer diameter of the inner tube 2 is equal to the inner diameter of the outer tube 1.

[0108] When using the evaluation apparatus of this embodiment:

[0109] The cross-sectional area A inside the evaluation device is the same as the cross-sectional area of ​​the inner tube; the equivalent seepage path L e This is the sum of the wall thicknesses of the inner and outer tubes; the total orifice area S of the permeable holes on the surface of the evaluation device is the total orifice area of ​​all the first permeable holes 3.

[0110] In this embodiment, after the evaluation device is inserted into the track bed, all the first water-permeable holes 3 are located between the bottom surface of the sleeper and a depth of 35cm below the sleeper.

[0111] Example 3:

[0112] A method for assessing the dirt and grime status of a track bed, based on the assessment device described in Example 2, further includes a first handle 8 connected to the inner tube 2.

[0113] The outer tube 1 has a circumferential groove 9 on its side wall that matches the first handle 8, and the first handle 8 extends out from the circumferential groove 9. When the first handle 8 is located at both ends of the circumferential groove 9, the inner tube 2 is in the first working position and the second working position, respectively. The outer tube 1 also has an axial groove 10 that communicates with the circumferential groove 9 on its side wall, and the axial groove 10 extends to the top of the outer tube 1.

[0114] In this embodiment, the circumferential groove 9 and the axial groove 10 together form an L-shaped structure.

[0115] In a more preferred embodiment, a second handle 11 is provided on the side wall of the outer tube 1.

[0116] In a more preferred embodiment, the bottom end of the outer tube 1 is provided with a pointed cone portion 12.

[0117] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0118] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Additionally, the term "connection" as used herein, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

Claims

1. A method of evaluating a state of contamination of a ballast, characterized by, Includes the following steps: S1. Insert the evaluation device, which is hollow inside and has several water-permeable holes on the surface, into the track bed to a set depth; S2. Close the water holes on the surface of the evaluation device and fill the evaluation device with water to the initial water level. S3. Open the water-permeable holes on the surface of the evaluation device and record the time it takes for the water level inside the evaluation device to drop to the set water level height. S4. Calculate the permeability coefficient; S5. Evaluate the dirtiness rate of the track bed based on the permeability coefficient.

2. The method of claim 1, wherein, The permeability coefficient is calculated using the following formula: ； where: K est is the permeability coefficient; I is the permeation efficiency; L e is the equivalent seepage path; H avg is the average water head height; C T is the water temperature viscosity correction coefficient.

3. A method of assessing the fouling state of a ballast bed according to claim 2, characterized in that The permeation efficiency is calculated using the following formula: ； In the formula: A is the cross-sectional area inside the evaluation device; S is the total orifice area of ​​the permeable holes on the surface of the evaluation device; h1 is the initial water level height; h2 is the set water level height; t is the time it takes for the water level inside the evaluation device to drop to the set water level height.

4. The method of claim 2, wherein, The equivalent seepage path is equal to the axial length of the permeable hole.

5. The method of claim 2, wherein, The average head height is calculated using the following formula: ； In the formula: h1 is the initial water level; h2 is the set water level.

6. The method of claim 2, wherein, The method for assessing the dirtiness rate of the track bed based on the permeability coefficient includes calculating the track bed dirtiness rate evaluation index using the following formula: ； In the formula, FI is the track bed contamination rate evaluation index; K est0 is the reference value of the permeability coefficient; and γ is the regression correction coefficient.

7. A method of assessing the fouling state of a ballast bed according to claim 6, characterized in that The permeability coefficient benchmark value was obtained through the following method: Construct a clean ballast track bed model box indoors; The evaluation device is inserted into the ballast bed model box of the clean ballast to a set depth; Perform steps S2 to S4, and use the calculated permeability coefficient as the reference value of the permeability coefficient.

8. The method for assessing the dirt and grime status of a track bed according to claim 6, characterized in that, The regression correction coefficients are obtained using the following method: Prepare several ballast particles with different dirt levels, and construct several track bed model boxes with different dirt levels indoors. The evaluation device was inserted into several track bed model boxes with different dirt rates to a set depth. Perform steps S2~S4 to obtain the permeability coefficients corresponding to different dirt levels; A model relating the permeability coefficient and the regression correction coefficient is established, and the regression correction coefficient is obtained by regression analysis.

9. The method for assessing the dirt and grime status of a track bed according to claim 1, characterized in that, The evaluation device includes an outer tube closed at the bottom and an inner tube rotatably fitted inside the outer tube. The outer tube has a plurality of first water-permeable holes on its side wall, and the inner tube has a plurality of second water-permeable holes on its side wall. The inner tube has a first working position and a second working position for rotational adjustment. When the inner tube is in the first working position, the second water-permeable hole is connected to the first water-permeable hole; When the inner tube is in the second working position, the second water-permeable hole is not connected to the first water-permeable hole.

10. The method for assessing the dirt and grime status of a track bed according to claim 9, characterized in that, The assessment device also includes a monitoring component for monitoring the water level inside the inner pipe.

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