System and method for monitoring railway bed sulfate erosion diseases based on diffusion dialysis

Abstract

The invention discloses a railway roadbed sulfate erosion disease monitoring system and method based on diffusion dialysis, the monitoring system comprises a detection box, the detection box comprises a box body and a box cover, an impurity filtering layer and a diffusion dialysis membrane are arranged in the detection box, and the diffusion dialysis membrane is arranged in the box body. The interior of the detection box is divided into three cavities from left to right: a sewage bin, a clear water bin and a detection bin; the impurity filtering layer is used for filtering solid impurities, and the diffusion dialysis membrane is used for allowing sulfate ions to selectively pass through; the detection bin is used for containing a Ba < 2 + > solution, and a conductivity detection device is further arranged in the detection bin and used for detecting the conductivity of the solution in the detection bin; the sewage bin is used for containing a water sample to be detected, and the water sample enters the clear water bin after being filtered by the impurity filtering layer.

Description

Technical Field

[0001] The invention relates to the technical field of railway roadbed engineering, and in particular to a monitoring system and method for railway roadbed sulfate erosion disease based on diffusion dialysis. Background Art

[0002] Railway subgrade transition sections are areas that require special treatment when connecting subgrades and structures, such as transition areas at the junctions of embankments and bridge abutments, embankments and transverse structures, embankments and cuttings, cuttings and tunnels. Setting up transition sections can gradually change the stiffness of the track and minimize the settlement difference, thereby reducing the vibration of the train and the line, slowing down the deformation of the subgrade structure, and ensuring the safe, smooth and comfortable operation of the train. Railway subgrade transition sections are usually constructed with cement graded crushed stone, which is prepared by dry mixing cement and graded crushed stone that meet the requirements of the specifications and then adding water to mix. It mainly plays a role in stiffness transition between different sections (bridges, tunnels, and roads), and is an important guarantee for the smooth operation of trains.

[0003] In recent years, the problem of high-speed railway embankment arching deformation has become very prominent, especially the arching problem of embankment transition section due to sulfate erosion has become increasingly serious. The sulfate erosion problem of cement-graded crushed stone can be divided into two categories according to the source of sulfate: endogenous sulfate erosion and exogenous sulfate erosion: (1) Endogenous sulfate erosion mainly refers to the use of cement or graded crushed stone with excessive sulfate content in the preparation of cement-graded crushed stone, thereby directly introducing a large amount of sulfate into the cement-graded crushed stone material. The sulfate further reacts with the cement in the cement-graded crushed stone and its hydration reaction products to generate expansive products, mainly ettringite, a colorless to yellow calcium aluminum sulfate mineral with a chemical molecule of 3CaO·Al2O33CaSO4·32H2O. The amount of crystal water is related to the environment, causing volume expansion and ultimately leading to embankment arching. (2) Exogenous sulfate erosion mainly refers to the presence of a large amount of sulfate in the environment (water and soil) of the roadbed transition section. Through the medium of water, sulfate comes into contact with cement-graded gravel and reacts with cement and its hydration products in the cement-graded gravel to produce expansive substances, mainly ettringite, which causes volume expansion and eventually leads to the arching of the roadbed.

[0004] The arching disease caused by sulfate erosion is characterized by its hidden location, slow development and irreversible reaction, making it a railway roadbed durability disease that is unpredictable in advance and extremely difficult to treat afterwards. High-speed railways have very strict requirements on the amount of arch deformation of the roadbed, which is difficult to distinguish directly with the naked eye. Usually, the railcar running on the rails detects the deformation of the track surface, and then comprehensively considers various factors to determine that it is caused by a reaction inside the roadbed. Then, samples are taken through on-site drilling and sent to the laboratory for testing to verify that the sulfate content exceeds the standard. It is finally determined that the roadbed arching is caused by sulfate erosion.

[0005] At present, the only way to test sulfate erosion is to observe the arch deformation on site first, then drill holes on site to take samples and send them to the laboratory for testing to verify whether the sulfate content exceeds the standard, and finally determine whether the roadbed arch is caused by sulfate erosion. Obviously, this detection method can only be implemented after obvious arch deformation is found, that is, it is possible to determine whether sulfate erosion has occurred. When the chemical reaction of sulfate erosion inside the roadbed has occurred, but the swelling products have not accumulated enough to produce obvious macroscopic deformation, there is no early warning. However, when obvious and detectable arch deformation occurs, the disease is already extremely serious, and it may be necessary to make a difficult decision to reduce the speed or stop the high-speed rail, which seriously threatens the safety and stable operation of the high-speed rail. In addition, this method is time-consuming, inefficient, and greatly affected by human factors. Therefore, it is urgent to develop a measurement method that can detect and prompt potential diseases in time in the early stage of the reaction, especially when the reaction conditions are ready but not yet reacted or just reacted, which is simple to operate, less affected by human factors, low cost, and will not affect the operation of the railway. Summary of the invention

[0006] The object of the present invention is to provide a monitoring system and method for railway roadbed sulfate erosion damage based on diffusion dialysis in view of the above problems.

[0007] In order to achieve its purpose, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a monitoring system for railway roadbed sulfate erosion disease based on diffusion dialysis, comprising a detection box, the detection box comprising a box body and a box cover, an impurity filtering layer and a diffusion dialysis membrane are arranged inside the detection box, and the inside of the detection box is divided into three cavities from left to right: a sewage tank, a clean water tank, and a detection tank;

[0009] The impurity filtering layer is used to filter solid impurities, and the diffusion dialysis membrane is used to allow sulfate ions to pass selectively; the detection chamber is used to hold Ba 2+ The detection chamber is also provided with a conductivity detection device for detecting the conductivity of the solution in the detection chamber; the sewage chamber is used to hold the water sample to be tested, and the water sample enters the clean water chamber after being filtered through the impurity filter layer.

[0010] Preferably, the impurity filtering layer is composed of a multi-layer filter mesh or a filter membrane.

[0011] Preferably, the top of the sewage bin is also provided with an overflow port for overflowing excess water; and the bottom of the sewage bin is provided with a sewage outlet for discharging solid impurities.

[0012] Preferably, the conductivity detection device is a conductivity sensor or a conductivity probe of a conductivity meter, and the conductivity probe is connected to an external conductivity meter; 2+ The solution is selected from BaCl2 solution.

[0013] Preferably, the monitoring system further comprises a water pipe, the top of the water pipe is open, and the cross section of the water pipe is U-shaped or V-shaped;

[0014] A water inlet is arranged on the top of the sewage tank, and a water guide pipe is connected to the water inlet of the sewage tank to guide the water gathered in the roadbed into the water guide pipe into the sewage tank.

[0015] Preferably, the monitoring system also includes an alarm device, a wireless communication module and a controller, the conductivity detection device is a conductivity sensor, the controller is used to obtain the detection result of the conductivity sensor, and the wireless communication module is used to send the detection result obtained by the controller to the host computer; the signal output end of the conductivity sensor is connected to the signal input end of the controller, and a signal output end of the controller is connected to the alarm device.

[0016] Preferably, the alarm device is a sound alarm or a warning light, which sends out an alarm signal when the conductivity is lower than a preset threshold; the host computer is a mobile phone, a tablet or a computer.

[0017] The second aspect of the present invention provides a real-time monitoring method for railway roadbed sulfate erosion damage, which adopts the above-mentioned monitoring system for monitoring, and comprises the following steps:

[0018] S1. Laying the monitoring system: drilling a hole from the bottom of the side of the railway roadbed to the inside of the roadbed, and placing the monitoring system in the drilled hole;

[0019] A water diversion channel is drilled obliquely downward on the side of the roadbed, a water guide pipe is placed in the water diversion channel, the end of the water guide pipe is connected to the water inlet of the sewage tank of the monitoring system, and the water collected in the water guide pipe is introduced into the sewage tank;

[0020] S2. Real-time monitoring: Monitor the conductivity test data in the test chamber. When the conductivity value approaches or reaches the set threshold, it means that SO4 is detected in the water sample. 2- ions, sulfate attack is occurring in the roadbed or will be affected by sulfate attack in the future.

[0021] Preferably, in step S1, a plurality of water diversion holes are drilled from top to bottom on the side of the roadbed, and the plurality of water diversion holes are arranged in the same straight line. A water pipe is placed in each water diversion hole, and the lower water pipe is longer than the upper water pipe to collect water leaking from the top to the bottom; the end of the lowest water pipe is connected to the water inlet of the sewage tank to introduce the collected water sample into the sewage tank.

[0022] Preferably, the monitoring system is taken out from the roadbed tunnel regularly to replace the Ba in the detection chamber. 2+ Solution to clean impurities in the sewage tank.

[0023] The beneficial effects of the present invention are:

[0024] 1. Accuracy: Through testing and calculation, it can be determined whether the roadbed transition section has been eroded by sulfate, and the sulfate (SO4 2- ) content and its degree of erosion on roadbed materials.

[0025] 2. Preventive: By regularly inspecting the railway subgrade, sulfate attack problems can be discovered in time before they become serious and corresponding preventive measures can be taken, thereby extending the service life of the railway.

[0026] 3. Economical: Compared with the railway damage and maintenance costs caused by sulfate erosion, the economic benefits of this method are significant. Placing the system of the present invention in the roadbed can monitor the sulfate erosion of the railway roadbed in real time. Compared with regular sampling and sending it to the laboratory for testing, on-site real-time monitoring greatly reduces labor costs and time costs.

[0027] 4. Safety: Sulfate erosion may lead to instability of the railway subgrade, thus affecting the safe operation of trains. Through timely detection, this risk can be effectively reduced, the safety of railway transportation can be guaranteed, and the implementation process of this method is harmless to the railway subgrade.

[0028] 5. Wide applicability: This method is not only applicable to the roadbed assessment of newly built railways, but also to the roadbed inspection and maintenance of existing railways. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the assembly diagram of the verification experimental device in Example 1.

[0030] Figure 2 This is the observation diagram of the experimental results of ions passing through the diffusion dialysis membrane of experimental group-1.

[0031] Figure 3 This is the observation diagram of the experimental results of ions passing through the diffusion dialysis membrane of experimental group-2.

[0032] Figure 4 It is a schematic diagram of the structure of a monitoring system for railway subgrade sulfate attack diseases of the present invention in a certain embodiment.

[0033] Figure 5 yes Figure 4 Schematic diagram of the structure of the central water pipe.

[0034] Figure 6The present invention is a schematic diagram of on-site installation and monitoring of the railway roadbed sulfate erosion disease monitoring system in the roadbed.

[0035] Figure 7 It is a control flow diagram of a monitoring system for railway roadbed sulfate attack in a certain embodiment of the present invention.

[0036] Figure 4-7 In the figure, the elements or structures represented by the reference numerals are:

[0037] Detection box 1, impurity filtering layer 2, diffusion dialysis membrane 3, sewage tank 4, clean water tank 5, detection tank 6, conductivity detection device 7, water pipe 8, alarm device 9, wireless communication module 10, controller 11. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereto.

[0039] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0040] Diffusion dialysis anion / cation membrane is the core of diffusion dialysis, referred to as anion / cation membrane. Anion / cation membrane is a polymer membrane containing ionic groups and having the ability to selectively permeate ions in solution. Its structure includes three parts: polymer skeleton, fixed group and movable ions. According to the different types of charges, it is mainly divided into anion membrane and cation membrane; the fixed group of the polymer skeleton of the anion membrane is positively charged, which can selectively pass through anions and block cations; the fixed group of the polymer skeleton of the cation membrane is negatively charged, which can selectively pass through cations and block anions. At present, there are different acid recovery diffusion dialysis membrane products on the market, which can separate different acids, such as hydrochloric acid, sulfuric acid, etc., and different products are selected according to different separation objects. The present invention applies the sulfuric acid diffusion dialysis membrane anion membrane to the sulfate ion detection of the present invention.

[0041] Sources of main materials and reagents:

[0042] Filter membrane: commercially available, filters solid impurities, allows water to pass, and is resistant to water immersion.

[0043] Sulfuric acid diffusion dialysis membrane anion membrane: purchased from Shandong Tianwei Membrane Technology Co., Ltd., model DDA3.

[0044] Barium chloride: BaCl2, commercially available.

[0045] Example 1

[0046] 1. Experimental Methods

[0047] In this embodiment, a preliminary experiment for feasibility verification of the detection principle is carried out in the laboratory to verify whether different ions can diffuse through the sulfuric acid dialysis membrane anion membrane.

[0048] Experimental apparatus: A laboratory H-type double-chamber electrolytic cell (sealed type) was used.

[0049] A total of 4 groups of experiments were set up: experimental group-1, experimental group-2, control group-1, and control group-2. For each group of experiments, a set of H-type double-chamber electrolytic cells was taken, and the side mouths of the left and right chamber electrolytic cell bottles were connected. The sulfuric acid diffusion dialysis membrane anion membrane (hereinafter referred to as diffusion dialysis membrane) was installed at the connection point and fixed with stainless steel clips (such as Figure 1 As shown in the figure, different solutions were poured into the left chamber and the right chamber respectively, and the conductivity of the solutions in the electrolytic cells of the left and right chambers was detected by a conductivity meter at 0 day, 7 days and 30 days respectively. By detecting the change of conductivity in the two chambers, it was verified whether the ions in the left chamber and the right chamber could pass through the diffusion dialysis membrane in the middle.

[0050] 1. Experimental Group-1

[0051] Experimental configuration: The solution in the left chamber is obtained by adding 0.6g of anhydrous sodium sulfate to 230g of 0.0001mol / L NaOH solution and stirring evenly, and the solution in the right chamber is 230g of 0.1mol / L BaCl2 aqueous solution, and there is a diffusion dialysis membrane between the side nozzles of the two chambers.

[0052] Objective: To verify whether sulfate ions in the alkaline solution of the left ventricle can enter the right ventricle through the diffusion dialysis membrane and react with BaCl2 in the right ventricle to precipitate, resulting in a decrease in the conductivity of the solution in the right ventricle.

[0053] 2. Experimental Group-2

[0054] Experimental configuration: The left chamber contains a solution of 230g pure water + 0.6g anhydrous sodium sulfate, the right chamber contains 230g of 0.1mol / L BaCl2 aqueous solution, and there is a diffusion dialysis membrane between the side nozzles of the two chambers.

[0055] Objective: To verify whether sulfate ions in the neutral solution of the left ventricle can enter the right ventricle through the diffusion dialysis membrane and react with BaCl2 in the right ventricle to cause a decrease in the conductivity of the solution in the right ventricle.

[0056] 3. Control group-1

[0057] Test configuration: The left chamber contains a solution of 150 g pure water + 0.6 g anhydrous sodium sulfate, the right chamber contains 150 g pure water, and there is a diffusion dialysis membrane between the side nozzles of the two chambers.

[0058] Objective: To verify whether sodium sulfate in the left ventricle can pass through the diffusion dialysis membrane.

[0059] 4. Control group-2

[0060] Experimental configuration: 158 g of pure water in the left chamber, 158 g of 0.1 mol / L BaCl2 aqueous solution in the right chamber, and a diffusion dialysis membrane between the side nozzles of the two chambers.

[0061] Objective: To verify whether barium chloride in the right ventricle can pass through the diffusion dialysis membrane.

[0062] 2. Experimental Results

[0063] The experimental results of the four groups of experiments are shown in Tables 1-4.

[0064] 1. Experimental Group-1

[0065] The results are shown in Table 1. The conductivity of the solution in the left and right chambers decreased to varying degrees, indicating that the sulfate ions in the left chamber passed through the diffusion dialysis membrane and entered the right chamber, where they reacted with the BaCl2 in the right chamber to precipitate ( Figure 2 ), resulting in a decrease in the conductivity of the solution in the right chamber.

[0066] Table 1 Conductivity test results of experimental group-1

[0067]

[0068] 2. Experimental Group-2

[0069] The results are shown in Table 2. The conductivity of the solutions in the left and right chambers decreased to varying degrees, indicating that the sulfate ions in the left chamber passed through the diffusion dialysis membrane and entered the right chamber, where they reacted with the BaCl2 in the right chamber to precipitate (e.g. Figure 3 ), resulting in a decrease in the conductivity of the solution in the right chamber.

[0070] Table 2 Conductivity test results of experimental group-2

[0071]

[0072] 3. Control group-1

[0073] The results are shown in Table 3. After a period of time, due to the concentration difference of sulfate in the left and right chambers, sulfate ions passed through the diffusion dialysis membrane from the left chamber to the right chamber, causing a change in conductivity. This shows that the use of this diffusion dialysis membrane allows sulfate ions to pass selectively.

[0074] Table 3 Conductivity test results of control group-1

[0075]

[0076]

[0077] 4. Control group-2

[0078] The results are shown in Table 4. At 30 days, the conductivity of the solution in the left and right chambers still did not change significantly, indicating that although there was a concentration difference of BaCl2 in the two chambers, BaCl2 could not pass through the diffusion dialysis membrane.

[0079] Table 4 Conductivity test results of control group-2

[0080]

[0081] The above results show:

[0082] When the left chamber was filled with sodium sulfate solution and the right chamber with pure water (control group-1), sulfate entered the right chamber through the diffusion dialysis membrane, causing the conductivity of the right chamber solution to increase significantly, while the conductivity of the solution in the left chamber decreased; when the left chamber was filled with pure water and the right chamber with BaCl2 solution (control group-2), since BaCl2 cannot pass through the diffusion dialysis membrane (water molecules cannot pass through the diffusion dialysis membrane either), even when the experiment lasted for 30 days, the conductivity of the solutions in the left and right chambers remained almost unchanged.

[0083] In railway subgrade projects, a large amount of cement-based materials are used, such as concrete, mortar, etc., including cement-graded crushed stone, all of which are alkaline. In addition, water in nature is generally neutral or slightly alkaline. Therefore, the sodium sulfate in experimental group 1 is prepared using NaOH solution, and the sodium sulfate in experimental group 2 is prepared using pure water. These two groups of experiments can simulate the main conditions in railway subgrade projects and in nature.

[0084] The above four groups of experiments prove that the decrease in the conductivity of the left and right chamber solutions in Experimental Group-1 and Experimental Group-2 is due to the sulfate ions entering the right chamber from the left chamber and reacting with BaCl2, rather than the decrease in the conductivity of the right chamber solution due to BaCl2 entering the left chamber from the right chamber. The diffusion dialysis membrane can prevent BaCl2 from moving from the right chamber with high concentration to the left chamber with low concentration, thereby maintaining a high concentration in the right chamber, and reacting with the sulfate ions that may enter the right chamber from the left chamber to precipitate, thereby causing the conductivity of the right chamber solution to decrease. The present invention utilizes BaCl2 to 2+ Solution with SO4 2- Ion reaction: It is feasible to judge whether sulfate attack has occurred in the railway subgrade by the change of solution conductivity. The monitoring method is accurate and reliable.

[0085] Example 2 A monitoring system for railway subgrade sulfate erosion based on diffusion dialysis

[0086] like Figure 4The railway roadbed sulfate erosion disease monitoring system based on diffusion dialysis of the present invention is mainly composed of a detection box 1, which includes a box body and a box cover. An impurity filter layer 2 and a diffusion dialysis membrane 3 are arranged inside the detection box 1, and the inside of the detection box 1 is divided into three chambers from left to right: a sewage tank 4, a clean water tank 5, and a detection tank 6; the impurity filter layer 2 is used to filter solid impurities, and the diffusion dialysis membrane 3 is used to allow sulfate ions to pass selectively; the detection tank 6 is used to hold Ba 2+ The detection chamber 6 is also provided with a conductivity detection device 7 for detecting the conductivity of the solution in the detection chamber 6; the sewage chamber 4 is used to contain the water sample to be tested, and the water sample enters the clean water chamber 5 after being filtered by the impurity filter layer 2. The sulfate ions in the water in the clean water chamber 5 pass through the diffusion dialysis membrane 3 and enter the detection chamber 6, causing the conductivity of the solution in the detection chamber 6 to decrease. The monitoring personnel judge that the water sample contains sulfate ions based on this.

[0087] In some embodiments, the impurity filtering layer 2 is composed of a multi-layer filter screen or a filter membrane; preferably, the multi-layer filter screen is composed of three layers of filter screens, the aperture of the first layer of filter screen is 1 mm, the aperture of the second layer of filter screen is 0.5 mm, and the aperture of the third layer of filter screen is 0.1 mm. The multi-layer filter screen is set to filter layer by layer to prevent large solid impurities from getting stuck in the holes of the small-aperture filter screen and causing blockage. The impurity filtering layer 2 can also directly purchase a water-resistant filter membrane product that can filter solid impurities and allow water to pass.

[0088] In some embodiments, Figure 5 As shown, the monitoring system for sulfate erosion disease of railway roadbed also includes a water pipe 8, the top of which is open, and the cross-section of the water pipe 8 is U-shaped or V-shaped; a water inlet is provided on the top of the sewage tank 4, and the water pipe 8 is connected to the water inlet of the sewage tank 4 to drain the water gathered in the roadbed into the water pipe 8 into the sewage tank 4.

[0089] In some embodiments, an overflow port is also provided on the top of the sewage tank 4 for overflowing excess water.

[0090] In some embodiments, a sewage outlet is provided at the bottom of the sewage tank 4 for discharging solid impurities, and the solid impurities in the sewage tank 4 can be cleaned regularly.

[0091] In some embodiments, the conductivity detection device 7 is a conductivity sensor or a conductivity probe of a conductivity meter, and the conductivity probe is connected to an external conductivity meter.

[0092] In some embodiments, Figure 7As shown, the monitoring system for railway roadbed sulfate erosion disease also includes an alarm device 9, a wireless communication module 10 and a controller 11. The conductivity detection device 7 is a conductivity sensor. The controller 11 is used to obtain the detection result of the conductivity sensor. The wireless communication module 10 is used to send the detection result obtained by the controller 11 to the host computer. The signal output end of the conductivity sensor is connected to the signal input end of the controller 11, and a signal output end of the controller 11 is connected to the alarm device 9. The alarm device 9 can be a sound alarm or a warning light. When the conductivity is lower than the preset threshold, an alarm signal is issued. The wireless communication module 10 can upload the detection result to the host computer through GPRS or the protocol of the LPWAN Internet of Things, and the host computer can be a mobile phone, a tablet or a computer for manual viewing. The wireless communication module 10 can be a ZigBee wireless communication or a Wi-Fi wireless communication module 10. The conductivity sensor detects the conductivity of the solution in the detection chamber 6, and then the controller 11 and the wireless communication module 10 transmit the detection result to the host computer, and the monitoring personnel read the conductivity through the host computer.

[0093] The working principle of the monitoring system for railway roadbed sulfate erosion disease of the present invention is:

[0094] The core is to use the passive diffusion principle driven by concentration gradient of diffusion dialysis membrane. When two solutions of different concentrations are separated by a semipermeable membrane (which only allows certain substances to pass through, such as SO4 2- ions), the solute will spontaneously diffuse from the high concentration side to the low concentration side until the concentration reaches equilibrium. 2+ The solution is equipped with a conductivity detection device for detecting the conductivity of the solution. When SO4 2- Before the ions enter the test chamber, the conductivity of the conductivity tester will always tend to a stable value. 2- After the ions enter the detection chamber, Ba 2+ The solution will react with SO4 2- The ions react to form precipitation, and the conductivity will first increase and then decrease. The reason for the increase is SO4 2- The entry of ions into the system will cause the amount of conductive substances to increase, and the reason for the decrease is SO4 2- Ion and Ba 2+ The precipitation reaction occurs, and the amount of conductive substances decreases. The conductivity data of the solution in the test chamber will be uploaded to the cloud, and the test personnel can observe the changes in the data through the host computer. When the data reaches the critical value, it means that SO4 has accumulated in the railway subgrade. 2- The amount of ions is high, sulfate attack is occurring or will occur in the future, and timely measures or methods need to be taken. 2+ With SO4 2- The reaction equation is as follows:

[0095]

[0096] Ba in the test chamber 2+ Ba in solution 2+ The content is known, and the SO4 in the ambient water can be calculated by conductivity. 2- The content is used to determine the risk of sulfate attack on the project.

[0097] In actual application, sulfate is almost undetectable in water samples taken from roadbed sections where sulfate erosion has not occurred, while sulfate ions are present in water samples taken from roadbeds where sulfate erosion is a risk or has occurred. As long as the BaCl2 content in the storage tank of the detection system is sufficient, it is possible to detect whether sulfate has entered and caused a significant change in the solution conductivity. 2- Ba as an ion indicator 2+ The filling capacity is limited, and the equipment deployed in the field is supplemented. 2+ Therefore, the device needs to be taken out and Ba injected into the detection chamber again after a period of service. 2+ Solution.

[0098] Application Example 1: Using the monitoring system of railway subgrade sulfate erosion disease of the present invention to detect

[0099] Build the monitoring system of Example 2.

[0100] Prepare a simulated solution of water samples of railway subgrades with sulfate erosion disease: add 0.6 g of anhydrous sodium sulfate to 230 g of 0.0001 mol / L NaOH solution and stir evenly to obtain a simulated solution. The concentration of sodium sulfate in the simulated solution is within the sulfate concentration range of water samples of railway subgrades with sulfate erosion disease.

[0101] Inject 230g of 0.1mol / L BaCl2 aqueous solution into the detection chamber of the monitoring system, inject 230g of the prepared simulation liquid into the sewage chamber of the monitoring system, and test the conductivity of the solution in the clean water chamber and the detection chamber after the water in the sewage chamber enters the clean water chamber. Then test the conductivity of the solution in the clean water chamber and the detection chamber at 7 days and 30 days. The test results are shown in Table 5:

[0102] Table 5 Conductivity test results of simulated liquid

[0103]

[0104] The sulfate in the sewage tank enters the detection tank and reacts with the Ba 2+ A reaction occurs, causing the conductivity of the solution in the detection chamber to decrease; the conductivity of the solution in the clean water chamber also decreases because the sulfate ions therein move to the detection chamber.

[0105] In actual application, water samples are collected by drilling holes at railway subgrades where sulfate erosion is observed. Holes are drilled from the side of the subgrade to the inside of the subgrade, and then a water pipe is inserted for drainage. Water samples are collected at the end of the water pipe using a glass bottle. Alternatively, water samples are directly collected from the drainage ditch of the subgrade, which can also reflect the sulfate erosion situation to a certain extent. The collected water samples are sent to the laboratory and tested using the monitoring system of the present invention. If the water sample contains sulfate ions, the conductivity of the solution in the detection chamber will drop significantly.

[0106] Example 3 A real-time monitoring method for railway roadbed sulfate erosion

[0107] The railway roadbed sulfate erosion disease monitoring system of the present invention in Example 2 is used for detection, and real-time monitoring is performed on the railway roadbed section where sulfate erosion is suspected to have occurred or predicted to be sulfate eroded. The monitoring system of the present invention can be manufactured as a small or micro device, placed inside the roadbed, and operated according to the following steps (the schematic diagram of the on-site monitoring is shown in FIG. Figure 6 shown):

[0108] S1. Laying the monitoring system: drilling a hole horizontally from the bottom of the side of the railway roadbed to the inside of the roadbed, drilling to a position about the middle of the roadbed, and placing the monitoring system of the present invention into the drilled hole;

[0109] A water diversion channel is drilled obliquely downward on the side of the roadbed to place a water pipe. The end of the water pipe is connected to the water inlet of the sewage tank of the monitoring system to introduce the water collected in the water pipe into the sewage tank.

[0110] In order to improve the accuracy of reflecting the sulfate erosion situation inside the roadbed, multiple water diversion holes arranged in the same straight line are drilled from top to bottom on the side of the roadbed. A water pipe is placed in each water diversion hole. The lower water pipe is longer than the upper water pipe and is used to collect water leaking from the top to the bottom. The water collected from the upper, middle and lower parts of the roadbed converges in the lowest water pipe. The end of the lowest water pipe is connected to the water inlet of the sewage tank to introduce the collected water samples into the sewage tank.

[0111] S2. Real-time monitoring: Monitor the conductivity test data in the test chamber. When the conductivity value approaches or reaches the set threshold, it means that SO4 is detected in the water sample. 2- ions, sulfate erosion is occurring in the roadbed or will be affected by sulfate erosion in the future, prompting the staff to promptly carry out disease treatment on the corresponding roadbed section.

Claims

1. A monitoring system for railway roadbed sulfate erosion based on diffusion dialysis, characterized by: The detection box includes a box body and a box cover. An impurity filtering layer and a diffusion dialysis membrane are arranged inside the detection box, and the inside of the detection box is divided into three cavities from left to right: a sewage tank, a clean water tank, and a detection tank; The impurity filtering layer is used to filter solid impurities, and the diffusion dialysis membrane is used to allow sulfate ions to selectively pass through; The detection chamber is used to hold Ba 2+ The test chamber is also provided with a conductivity detection device for detecting the conductivity of the solution in the test chamber; The sewage tank is used to hold water samples to be tested, and the water samples enter the clean water tank after being filtered through the impurity filtering layer.

2. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 1 is characterized by: The impurity filtering layer is composed of a multi-layer filtering net or a filtering membrane.

3. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 1 is characterized by: The top of the sewage bin is also provided with an overflow port for overflowing excess water; the bottom of the sewage bin is provided with a sewage outlet for discharging solid impurities.

4. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 1 is characterized by: The conductivity detection device is a conductivity sensor or a conductivity probe of a conductivity meter, and the conductivity probe is connected to an external conductivity meter; 2+ The solution is selected from BaCl2 solution.

5. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 1 is characterized by: The monitoring system further comprises a water pipe, the top of the water pipe is open, and the cross section of the water pipe is U-shaped or V-shaped; A water inlet is arranged on the top of the sewage tank, and a water guide pipe is connected to the water inlet of the sewage tank to guide the water gathered in the roadbed into the water guide pipe into the sewage tank.

6. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 1 or 5, characterized in that: The monitoring system also includes an alarm device, a wireless communication module and a controller. The conductivity detection device is a conductivity sensor. The controller is used to obtain the detection result of the conductivity sensor. The wireless communication module is used to send the detection result obtained by the controller to a host computer. The signal output end of the conductivity sensor is connected to the signal input end of the controller, and a signal output end of the controller is connected to the alarm device.

7. The railway roadbed sulfate attack disease monitoring system based on diffusion dialysis according to claim 6 is characterized by: The alarm device is a sound alarm or a warning light, which sends out an alarm signal when the conductivity is lower than a preset threshold; The host computer is a mobile phone, a tablet or a computer.

8. A real-time monitoring method for railway roadbed sulfate erosion damage, characterized in that: Monitoring using the monitoring system according to any one of claims 5 to 7 comprises the following steps: S1. Laying the monitoring system: drilling a hole from the bottom of the side of the railway roadbed to the inside of the roadbed, and placing the monitoring system according to any one of claims 4 to 6 into the drilled hole; A water diversion channel is drilled obliquely downward on the side of the roadbed, a water guide pipe is placed in the water diversion channel, the end of the water guide pipe is connected to the water inlet of the sewage tank of the monitoring system, and the water collected in the water guide pipe is introduced into the sewage tank; S2. Real-time monitoring: Monitor the conductivity test data in the test chamber. When the conductivity value approaches or reaches the set threshold, it means that SO4 is detected in the water sample. 2- ions, sulfate attack is occurring in the roadbed or will be affected by sulfate attack in the future.

9. The real-time monitoring method according to claim 8, characterized in that: In step S1, a plurality of water diversion channels are drilled from top to bottom on the side of the roadbed. The plurality of water diversion channels are arranged in the same straight line. A water pipe is placed in each water diversion channel. The lower water pipe is longer than the upper water pipe and is used to collect water leaking from the top to the bottom. The end of the lowest water pipe is connected to the water inlet of the sewage tank to introduce the collected water sample into the sewage tank.

10. The real-time monitoring method according to claim 8, characterized in that: Regularly remove the monitoring system from the roadbed channel and replace the Ba in the detection chamber. 2+ Solution to clean impurities in the sewage tank.

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