Using method of testing device for simulating ion erosion of PCCP (prestressed concrete cylinder pipe) protective layer

Abstract

A use method of the test device for simulating ion erosion of the PCCP protective layer comprises the following steps: S1, region division: selecting a test object, and firstly dividing the test object into four regions, namely a region I, a region II, a region III and a region IV; dividing each subarea into three test areas, namely a test area A, a test area B and a test area C; s2, making a test plan: executing sulfate ion erosion comparison in a partition I, executing chloride ion erosion comparison in a partition II, executing protective measure comparison in a partition III, and executing a mixed comparison test in a partition IV; s3, making a comparison scheme; s4, making a dry-wet cycle scheme; s5, preparing test conditions; s6, liquid filling is executed; s7, executing a dry-wet cycle; s8, judging whether the dry-wet cycle needs to be ended or not: if Seq is equal to L, ending the dry-wet cycle, and continuing S9; otherwise, indicating that all times of dry-wet cycle treatment is not completed, and returning to S6; s9, extracting a sample; and S10, analyzing a result.

Description

Technical Field

[0001] The present disclosure relates to the field of ion corrosion experiments in construction engineering, and in particular to a method for using a test device for simulating ion corrosion of a PCCP protective layer under the influence of multiple factors under load. Background Art

[0002] my country's Northwest region is rich in large areas of saline soil. Structural cracking, powdering, steel corrosion and local erosion caused by corrosive salt erosion such as sulfates and chlorides can easily cause safety hazards in engineering buildings. Prestressed Concrete Cylinder Pipe (PCCP) refers to a water pipe made by winding annular prestressed steel wire on a high-strength concrete pipe core with a steel cylinder, and then spraying a dense cement mortar protective layer on it. There is an unbalanced distribution of water resources in the Northwest region, and natural water resources in some areas are difficult to meet the demand for industrial water. A large number of long-distance water pipeline projects are needed to allocate water resources. Along with the erosion of saline soil, groundwater accumulation, and developed irrigation agriculture, the salinity of the soil in the stratum where the buried pipelines are located is complex and changeable, such as PH, Cl - and SO4 2- The difference may cause corrosion or even bursting of PCCP.

[0003] At present, the research on ion corrosion of PCCP mainly adopts a simplified method, that is, ordinary immersion test without load, and the influence of load has not been considered. Ion corrosion of PCCP protective layer is the result of the combined effect of materials, load and environment. The roller spraying process of PCCP mortar protective layer during pipe making, wire relaxation during curing, creep and shrinkage of concrete, and load borne by the pipe body during operation will cause the physical and load state of the mortar protective layer to change, affecting the ion corrosion process.

[0004] In order to meet engineering needs, improving the PCCP durability test method is one of the inevitable processes to solve the durability problem. It is particularly necessary to design a method that can simulate ion erosion of the PCCP protective layer under equivalent internal pressure. Summary of the invention

[0005] In response to the above technical problems in the related art, the present disclosure proposes a method for using a test device for simulating ion corrosion of a PCCP protective layer, which overcomes the above shortcomings of the prior art through a method for using a device for simulating ion corrosion of a PCCP protective layer.

[0006] To achieve the above technical objectives, the technical solution of the present disclosure is implemented as follows: A method for using a PCCP protective layer testing device for simulating ion corrosion comprises the following steps: S1. Divide the area: select a test object for simulating the PCCP protective layer, first divide the test object into 4 partitions, namely, partition I, partition II, partition III, and partition IV; then divide each partition into 3 test areas, namely, test area A, test area B, and test area C; S2 formulates a test plan: Zone I performs a comparison of sulfate ion corrosion at different concentrations, Zone II performs a comparison of chloride ion corrosion at different concentrations, Zone III performs a comparison of different protective measures, and Zone IV performs a mixed comparison test; S3 develops a comparison plan: For test area A, test area B, and test area C in partition I, 1% concentration Na2SO4 solution, 3% concentration Na2SO4 solution, and 5% concentration Na2SO4 solution are respectively prepared; For test area A, test area B, and test area C in partition II, 1% concentration NaCl solution, 3% concentration NaCl solution, and 5% concentration NaCl solution are prepared respectively; For test area A, test area B, and test area C in zone III, first prepare 5% NaCl solution respectively, then apply protective coating 1, protective coating 2, and protective coating 3 respectively and plan to perform dry-wet cycle treatment; For test area A, test area B, and test area C in zone IV, 5% NaCl solution, 5% Na2SO4 solution, and a mixed solution of 5% NaCl and 5% Na2SO4 were prepared respectively; test area A and test area B were planned to be treated with dry-wet cycles respectively; S4 formulates a dry-wet cycle plan: each test area that is planned to be subjected to a dry-wet cycle treatment is respectively regarded as a separate area to be subjected to a dry-wet cycle treatment, and the upper limit of the dry-wet cycle treatment is defined as L times. The number of times the dry-wet cycle treatment is currently performed is defined as Seq, and Seq is initialized to 0, that is, the three test areas A, B, and C in the partition III, and the test areas A and B in the partition IV are respectively regarded as an area to be subjected to a dry-wet cycle treatment, and each needs to undergo L dry-wet cycles, and Seq is used to represent the cumulative number of dry-wet cycle treatments that have been performed; S5 is equipped with test conditions: Finally, each test area is equipped with a corresponding test device; the test device includes a solution erosion container, the solution erosion container is close to one side of the corresponding test area, and the other side of the test area is soaked in water; S6 performs liquid filling: using the solution configured corresponding to each test area, the solution corrosion container of the corresponding test device is filled with liquid until it is full and remains full; S7 performs a wet-dry cycle: for all wet-dry cycle areas, soak for N days and dry for M days respectively. Specifically, for each test device corresponding to the wet-dry cycle area, firstly, the solution erosion container is filled with the corresponding solution and maintained for N days, i.e., soaking work; then, the solution in the solution erosion container is drained, and the wet-dry cycle area and the test device are blown dry and maintained dry for M days, i.e., drying work; finally, Seq is incremented by 1, which is counted into the wet-dry operation of this cycle; S8 determines whether the dry-wet cycle should be ended: if Seq=L, it means that the current cumulative number of dry-wet cycles has reached the cycle upper limit, and the dry-wet cycle should be ended, so continue S9; otherwise, it means that all dry-wet cycle processing has not been completed, so return to S6; S9 extracting samples: after waiting time T, selecting a number of the test areas, and then extracting a number of core samples; S10 result analysis: All core samples were processed into slices; each core sample slice was ground, the chloride ion concentration was determined by titration, the sulfate ion concentration was measured by weighing, and the concentration of ions intruding into the core sample was plotted as a function of depth, and the test results of different partitions were compared.

[0007] Preferably, the slice thickness depends on actual needs, and is preferably 3 mm.

[0008] Preferably, in S7, N=2, M=1, which means that each dry-wet cycle treatment requires 2 days of soaking and 1 day of drying respectively.

[0009] Preferably, in S5 or S8, L=10, which means that the dry-wet cycle treatment needs to be repeated 10 times.

[0010] Preferably, in S9, T is 10 days, which means that after the dry-wet cycle treatment, sampling is continued after waiting for 10 days.

[0011] Preferably, the specific structure of the testing device can be realized by using the existing technology, and can also be preferably: the solution erosion container can be provided with a container cavity, the container cavity is connected to a solution placement barrel downward and is connected to a liquid level display barrel upward, and a liquid extraction hose is connected between the inside of the liquid level display barrel and the inside of the solution placement barrel; Preferably, the front side of the solution erosion container is provided with a plurality of transparent windows, and the rear side of the solution erosion container is closely attached to the corresponding test area. Preferably, the front side of the solution erosion container is provided with 3 transparent windows.

[0012] Preferably, the lower end of the liquid extraction hose located inside the solution placement barrel is connected to a water pump, and the inner cavity of the container is further connected to a blower, and the blower participates in the drying work of the dry-wet cycle.

[0013] Preferably, in S6, for the filling operation of each test area, the corresponding test device performs the following steps: S6.1: Turn on the water pump to extract the solution in the solution placement barrel. The solution flows from bottom to top through the liquid extraction hose into the liquid level display barrel and then into the solution erosion container; S6.2: Observe the liquid level indicator to see if the solution erosion container is full; S6.3: If the solution erosion container is full, turn off the water pump; otherwise, return to S6.1.

[0014] Preferably, the test object may be the PCCP pipe body 13 depending on actual needs.

[0015] Preferably, partition I, partition II, partition III and partition IV are all divided on the PCCP pipe body, and the circumferential surface of the PCCP pipe body is divided into partition I, partition II, partition III and partition IV from bottom to top, and each partition is divided into three test areas, and each test area is provided with a corresponding test device.

[0016] Therefore, all test devices are arranged on the circumferential surface of the PCCP pipe body, one side of all test areas is located on the outer wall of the PCCP pipe body and the other side is located on the inner wall of the PCCP pipe body; and because the solution erosion container is in close contact with one side of the corresponding test area, the solution erosion container is in close contact with the outer wall of the PCCP pipe body. During implementation, the solution erosion container is in close contact with one side of the corresponding test area, and water is injected into the PCCP pipe body, so the other side of the test area is infiltrated with water.

[0017] Preferably, the sampling method in S9 is determined according to the needs, which can be: select several test areas, remove the transparent windows of the corresponding test devices, and use a water drill to extract several core samples from the PCCP pipe body. Then, the drill hole can be sealed and the transparent window can be installed again, so that it can be reused to perform other test schemes.

[0018] Preferably, the PCCP pipe body is sleeved on the outside of the steel inner liner, a base is provided at the bottom of the steel inner liner, the bottom of the PCCP pipe body is close to the top of the base, and the space enclosed between the inner wall of the PCCP pipe body and the outer wall of the steel inner liner forms a pipe body cavity; water is injected into the PCCP pipe body by injecting water into the pipe body cavity.

[0019] Preferably, a layered scaffolding is set up around the PCCP pipe body, and the PCCP pipe body is subdivided into zone I, zone II, zone III, and zone IV by the scaffolding.

[0020] Preferably, the top of the PCCP pipe body is connected to a PCCP pipe exhaust port, and the bottom of the PCCP pipe body is connected to an internal pressure loading machine through a water pipe, and water is injected into the inner cavity of the pipe body through the internal pressure loading machine.

[0021] Preferably, the water conduit is provided with an internal water pressure gauge, which continuously monitors the water pressure inside the water conduit.

[0022] Preferably, in each testing device, at least one air blast port is provided on the top of the inner cavity of the container, and the blower can be connected to the inner cavity of the container via a three-way connecting pipe or at least one conduit through the corresponding air blast port.

[0023] Preferably, the transparent window is made of a transparent PC board; the solution erosion container is made of a rust-proof shell; and clamps are respectively provided on the upper and lower sides of the solution erosion container to fix it on the circumferential surface of the PCCP pipe body.

[0024] Preferably, a rainproof pressure plate is provided on the top of the liquid level display barrel, and an exhaust port is provided on the rainproof pressure plate, and the exhaust port is connected to the inside of the liquid level display barrel.

[0025] Preferably, at least one blast port is provided at the top of the inner cavity of the container, and the blower can be connected to the inner cavity of the container via a three-way connecting pipe or at least one conduit through the corresponding blast port.

[0026] Preferably, a liquid discharge port is provided at the bottom of the inner cavity of the container, and the liquid discharge port is connected to the solution placement barrel; a liquid inlet is provided at the top of the inner cavity of the container, and the liquid inlet is connected to the liquid level display barrel.

[0027] Preferably, the PCCP pipe body can be connected to the outside through a connecting flange, and the specific method can be: a connecting flange is provided at the top and bottom of the PCCP pipe body, respectively, and a flange water injection port and a flange exhaust port are provided on the connecting flange, and the flange water injection port and the flange exhaust port are respectively connected to the inner cavity of the pipe body, and the flange exhaust port at the top can be connected to the PCCP pipe exhaust port, and the flange water injection port at the bottom is connected to the water pipe, so as to realize water injection or exhaust of air into the inner cavity of the pipe body through the connecting flange. The connecting flange belongs to the prior art. During implementation, the internal pressure loading machine drives the water body to flow through the water pipe, and then injects water into the inner cavity of the pipe body through the flange water injection port, and exhausts the air in the inner cavity of the pipe body through the flange exhaust port.

[0028] Beneficial effects of the present disclosure: Compared with the prior art, the present disclosure solves the process simulation of ion corrosion of the PCCP protective layer under real load conditions and explores the key factors affecting the corrosion effect.

[0029] The present disclosure divides the PCCP pipe body into several partitions, each of which is further divided into several test areas, each of which is a separate test unit and is equipped with an independent test device, so there will be no crossover of test solutions between different test units, thereby ensuring the accuracy of the test results and avoiding the test result error problem caused by the cross-talk of test solutions caused by the need to design multiple test pools in the prior art. The present disclosure can achieve artificial or automatic control of simulated load values ​​through the cooperation of components such as internal pressure loaders, thereby simulating different test conditions or environments in various regions, further expanding the scope of application of the present disclosure.

[0030] As the diversion and drainage project goes deeper into the complex environment of high salinity in the northwest, this paper faces the need for the construction of modern high-quality water conservancy infrastructure. The study of ion corrosion laws under real load levels can provide guarantees for the safe operation of long-distance water pipelines and provide strong support for the construction of the national water network. The device-level supporting test has great theoretical and practical significance for the durability design and evaluation of PCCP in high-salinity areas, which can promote the improvement of PCCP industry technology and help its promotion in complex erosion environments.

[0031] The present disclosure avoids the problem of low load level caused by the brittleness and discreteness of concrete in ion corrosion tests under general loads, reflects the high tensile strain characteristics of the PCCP protective layer, realizes the study of ion corrosion characteristics under long-term real loads and multiple factors, and more accurately reveals the time-varying law of ion corrosion PCCP protection. The present disclosure uses a no-load immersion test as a control group, and with the help of PCCP internal pressure loading equipment, designs a multi-partitioned independent ion corrosion device on the surface of the protective layer, and can consider load, single chloride / sulfate ion corrosion, coupled ion corrosion, ion concentration, dry-wet cycle and surface protection measures to carry out prototype test research on ion corrosion under long-term high internal pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the structure of the testing device for simulating ion corrosion of the PCCP protective layer described in the present invention.

[0034] Figure 2 It is a schematic structural diagram of the testing device preferred in the present disclosure.

[0035] Figure 3is a front view of the solution erosion container used in the testing device described in the present disclosure.

[0036] Figure 4 is a perspective view of a solution erosion container used in the testing device described in the present disclosure.

[0037] Figure 5 It is a top-down cross-sectional view of the cooperation between the test device and the PCCP pipe body when the test object adopts a PCCP pipe body.

[0038] Figure 6 It is a main perspective cross-sectional view of the cooperation between the test device and the PCCP pipe body when the test object adopts a PCCP pipe body.

[0039] Figure 7 It is a three-dimensional structural diagram of the PCCP pipe body, internal pressure loading machine, water pipe, internal pressure loading machine, and connecting flange when the test object adopts the PCCP pipe body (the test device, scaffolding, etc. are removed).

[0040] In the figure: 1. solution placement barrel; 2. clamp; 3. liquid outlet; 4. vertical sealing strip; 5. solution erosion container; 501. transparent window; 6. three-way connecting pipe; 7. blower; 8. exhaust port; 9. rainproof pressure plate; 10. liquid level display barrel; 11. liquid extraction hose; 12. water pump; 13. PCCP pipe body; 14. PCCP pipe exhaust port; 15. scaffolding; 16. internal pressure loader; 1601. top opening of internal pressure loader; 17. water pressure gauge; 18. water guide pipe; 19. connecting flange; 1901. flange water inlet; 1902. flange exhaust port; 20. steel liner; 2001. base. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0042] like Figure 1-7 As shown, in order to facilitate the understanding of the above technical solutions of the present disclosure, the above technical solutions of the present disclosure are described in detail below through specific usage methods.

[0043] The method for using the simulated ion erosion PCCP protective layer comprises the following steps: S1. Divide the area: select a test object for simulating the PCCP protective layer, first divide the test object into 4 partitions, namely, partition I, partition II, partition III, and partition IV; then divide each partition into 3 test areas, namely, test area A, test area B, and test area C; S2 formulates a test plan: Zone I performs a comparison of sulfate ion corrosion at different concentrations, Zone II performs a comparison of chloride ion corrosion at different concentrations, Zone III performs a comparison of different protective measures, and Zone IV performs a mixed comparison test; S3 develops a comparison plan: For test area A, test area B, and test area C in partition I, 1% concentration Na2SO4 solution, 3% concentration Na2SO4 solution, and 5% concentration Na2SO4 solution are respectively prepared; For test area A, test area B, and test area C in partition II, 1% concentration NaCl solution, 3% concentration NaCl solution, and 5% concentration NaCl solution are prepared respectively; For test area A, test area B, and test area C in zone III, first prepare 5% NaCl solution respectively, then apply protective coating 1, protective coating 2, and protective coating 3 respectively and plan to perform dry-wet cycle treatment; For test area A, test area B, and test area C in zone IV, 5% NaCl solution, 5% Na2SO4 solution, and a mixed solution of 5% NaCl and 5% Na2SO4 were prepared respectively; test area A and test area B were planned to be treated with dry-wet cycles respectively; S4 formulates a dry-wet cycle plan: each test area that is planned to be subjected to a dry-wet cycle treatment is respectively regarded as a separate area to be subjected to a dry-wet cycle treatment, and the upper limit of the dry-wet cycle treatment is defined as L times. The number of times the dry-wet cycle treatment is currently performed is defined as Seq, and Seq is initialized to 0, that is, the three test areas A, B, and C in the partition III, and the test areas A and B in the partition IV are respectively regarded as an area to be subjected to a dry-wet cycle treatment, and each needs to undergo L dry-wet cycles, and Seq is used to represent the cumulative number of dry-wet cycle treatments that have been performed; S5 is equipped with test conditions: Finally, each test area is equipped with a corresponding test device; the test device includes a solution erosion container 5, the solution erosion container 5 is closely attached to one side of the corresponding test area, and the other side of the test area is soaked in water; S6 performs liquid filling: using the solution configured corresponding to each test area, the solution corrosion container 5 of the corresponding test device is filled with liquid until it is full and remains full; S7 performs a wet-dry cycle: for all wet-dry cycle areas, soak for N days and dry for M days respectively. Specifically, for each test device corresponding to the wet-dry cycle area, firstly, the solution erosion container 5 is filled with the corresponding solution and kept for N days, that is, soaking work; then, the solution in the solution erosion container 5 is discharged, and the wet-dry cycle area and the test device are blown dry and kept dry for M days, that is, drying work; finally, Seq is increased by 1, which is counted into the wet-dry operation of this cycle; S8 determines whether the dry-wet cycle should be ended: if Seq=L, it means that the current cumulative number of dry-wet cycles has reached the cycle upper limit, and the dry-wet cycle should be ended, so continue S9; otherwise, it means that all dry-wet cycle processing has not been completed, so return to S6; S9 extracting samples: after waiting time T, selecting a number of the test areas, and then extracting a number of core samples; S10 result analysis: All core samples were processed into slices; each core sample slice was ground, the chloride ion concentration was determined by titration, the sulfate ion concentration was measured by weighing, and the concentration of ions intruding into the core sample was plotted as a function of depth, and the test results of different partitions were compared.

[0044] In one embodiment, the slice thickness is determined according to actual needs, and is preferably 3 mm.

[0045] In one embodiment, in S7, N=2, M=1, which means that each dry-wet cycle treatment requires 2 days of soaking and 1 day of drying respectively.

[0046] In one embodiment, in S5 or S8, L=10, which means that the dry-wet cycle treatment needs to be repeated 10 times.

[0047] In one embodiment, in S9, T is 10 days, which means that after the dry-wet cycle treatment, sampling is continued after waiting for 10 days.

[0048] In a certain embodiment, the specific structure of the testing device can be implemented using existing technology, or it can be preferably: the solution corrosion container 5 can be provided with a container inner cavity, the container inner cavity is connected to the solution placement barrel 1 downward and is connected to the liquid level display barrel 10 upward, and a liquid extraction hose 11 is connected between the interior of the liquid level display barrel 10 and the interior of the solution placement barrel 1.

[0049] In one embodiment, the front side of the solution erosion container 5 is provided with a plurality of transparent windows 501 , and the rear side of the solution erosion container 5 is closely attached to the corresponding test area. Preferably, three transparent windows 501 are provided on the front side of the solution erosion container 5 .

[0050] In one embodiment, the lower end of the liquid extraction hose 11 located inside the solution placement barrel 1 is connected to a water pump 12, and the inner cavity of the container is further connected to a blower 7, through which the blower 7 participates in the drying work of the dry-wet cycle.

[0051] In one embodiment, in S6, for the filling operation of each test area, the corresponding test device performs the following steps: S6.1: Turn on the water pump 12 to extract the solution in the solution placement barrel 1. The solution flows from bottom to top through the liquid extraction hose 11 into the liquid level display barrel 10 and into the solution erosion container 5; S6.2: Observe whether the solution erosion container 5 is full through the liquid level display barrel 10; S6.3: If the solution erosion container 5 is full, turn off the water pump 12; otherwise, return to S6.1.

[0052] In a certain embodiment, the test object may be the PCCP pipe body 13 depending on actual needs.

[0053] In a certain embodiment, partition I, partition II, partition III, and partition IV are all divided on the PCCP pipe body 13, and the circumferential surface of the PCCP pipe body 13 is divided into partition I, partition II, partition III, and partition IV from bottom to top, respectively, and each partition is divided into three test areas, and each test area is provided with a corresponding test device.

[0054] Therefore, all test devices are arranged on the circumferential surface of the PCCP tube body 13, one side of all test areas is located on the outer wall of the PCCP tube body 13 and the other side is located on the inner wall of the PCCP tube body 13; and because the solution erosion container 5 is close to one side of the corresponding test area, the solution erosion container 5 is close to the outer wall of the PCCP tube body 13.

[0055] During implementation, the solution erosion container 5 is closely attached to one side of the corresponding test area, and water is injected into the PCCP tube body 13, so that the other side of the test area is soaked in water. The rear side of the solution erosion container 5 actually serves as a side closely attached to the test area or the outer side wall of the subsequent PCCP tube body 13.

[0056] In one embodiment, the sampling method in S9 is determined according to the needs, and can be: select several test areas, remove the transparent windows 501 of the corresponding test devices, and use a water drill to extract several core samples from the PCCP pipe body 13. Then, the drill hole can be sealed and the transparent window 501 can be installed again, so that it can be reused to perform other test schemes.

[0057] In a certain embodiment, the PCCP tube body 13 is sleeved on the outside of the steel inner liner 20, and a base 2001 is provided at the bottom of the steel inner liner 20. The bottom of the PCCP tube body 13 is close to the top of the base 2001. The space enclosed between the inner wall of the PCCP tube body 13 and the outer wall of the steel inner liner 20 forms an inner cavity of the tube body. Water is injected into the inner cavity of the tube body to achieve water injection into the PCCP tube body 13.

[0058] In one embodiment, a layered scaffold 15 is set up around the PCCP pipe body 13 , and the PCCP pipe body 13 is subdivided by the scaffold 15 into zone I, zone II, zone III, and zone IV.

[0059] In one embodiment, a PCCP pipe exhaust port 14 is connected to the top of the PCCP pipe body 13 , and an internal pressure loading machine 16 is connected to the bottom of the PCCP pipe body 13 through a water pipe 18 , and water is injected into the inner cavity of the pipe body through the internal pressure loading machine 16 .

[0060] In one embodiment, the water pipe 18 is provided with an internal water pressure gauge 17 , and the internal water pressure gauge 17 continuously monitors the water pressure inside the water pipe 18 .

[0061] In one embodiment, in each test device, at least one air blast port is disposed on the top of the inner cavity of the container, and the blower 7 can be connected to the inner cavity of the container via a three-way connecting pipe 6 or at least one conduit through the corresponding air blast port.

[0062] In a certain embodiment, the transparent window 501 is made of a transparent PC board; the solution erosion container 5 is made of a rust-proof shell; and the upper and lower sides of the solution erosion container 5 are respectively provided with clamps 2 for fixing it on the circumferential surface of the PCCP tube body 13.

[0063] In one embodiment, a rainproof pressure plate 9 is provided on the top of the liquid level display barrel 10 , and an exhaust port 8 is provided on the rainproof pressure plate 9 , and the exhaust port 8 is connected to the inside of the liquid level display barrel 10 .

[0064] In one embodiment, at least one blast hole is disposed on the top of the inner cavity of the container, and the blower 7 can be connected to the inner cavity of the container via a three-way connecting pipe 6 or at least one conduit through the corresponding blast hole.

[0065] In one embodiment, a liquid discharge port 3 is provided at the bottom of the inner cavity of the container, and the liquid discharge port 3 is connected to the solution placement barrel 1 ; a liquid inlet is provided at the top of the inner cavity of the container, and the liquid inlet is connected to the liquid level display barrel 10 .

[0066] In a certain embodiment, the PCCP pipe body 13 can be connected to the outside through a connecting flange 19. The specific method can be: a connecting flange 19 is provided at the top and bottom of the PCCP pipe body 13, respectively. A flange water injection port 1901 and a flange exhaust port 1902 are provided on the connecting flange 19. The flange water injection port 1901 and the flange exhaust port 1902 are respectively connected to the inner cavity of the pipe body. The flange exhaust port 1902 at the top can be connected to the PCCP pipe exhaust port 14, and the flange water injection port 1901 at the bottom is connected to the water guide pipe 18, so as to realize water injection or exhaust of air into the inner cavity of the pipe body through the connecting flange 19. The connecting flange 19 belongs to the prior art. When implemented, the internal pressure loading machine 16 drives the water body to flow through the water guide pipe 18, and then injects water into the inner cavity of the pipe body through the flange water injection port 1901, and exhausts the air in the inner cavity of the pipe body through the flange exhaust port 1902.

[0067] For example, if the PCCP pipe body 13 is used as the test object, the test device for simulating ion erosion of the protective layer of the prestressed steel cylinder concrete pipe (PCCP) under load is operated through the internal pressure loading machine 16, the PCCP pipe body 13, and several solution erosion containers 5 and other cooperative components. The PCCP pipe body 13 acts as a simulated PCCP protective layer, and the solution erosion container 5 acts as a container for containing the corrosive solution used for testing. The rear side of the solution erosion container 5 is in close contact with the circumferential surface of the PCCP pipe body 13 (simulating the PCCP protective layer), and the solution erosion container 5 is provided with several transparent windows 501; the inner cavity of the solution erosion container 5 can be connected to the solution placement barrel 1 downward, and can be connected to the liquid level display barrel 10 or the blower 7 upward; the solution placement barrel has a built-in water pump, and the pump body is connected to the liquid level display barrel 10 through a hose; the solution erosion container 5 can realize the dry-wet cycle of the PCCP pipe body 13 (simulating the PCCP protective layer) with the help of the water pump 12 and the blower 7; the liquid erosion container 5 can also realize remote page monitoring with the help of a camera. Compared with the existing technology, this test device has created a process that can simulate the ion corrosion of the protective layer of PCCP under the actual load state, reducing the infrastructure cost and the amount of corrosion solution used, and solving the problem of different corrosion solutions intercommunication. It can comprehensively consider the effects of various factors on the durability of PCCP, such as solution type and concentration, coating type and thickness, long-term immersion, dry-wet cycle and cathodic protection. Among them, the PCCP pipe body 13 represents a prestressed steel cylinder concrete pipe, referred to as PCCP, and its full English name is Prestressed Concrete Cylinder Pipe.

[0068] Working principle of the disclosed method: During the implementation of the method for using the test device for simulating ion erosion of the PCCP protective layer, internal water pressure can be applied to the inner wall of the PCCP pipe body 13 by a pressurizing device such as an internal pressure loader, so the actual load state of the PCCP protective layer can be simulated. The PCCP pipe body 13 is divided into N partitions by a scaffold, and each partition is divided into M test partitions by M solution erosion containers 5 arranged thereon, and each test partition can be configured with an independent test solution or coated with a specific protective coating or subjected to dry and wet treatments. Preferably, N=4, M=3, that is, there are 4 partitions in total, and each partition is provided with 3 solution erosion containers 5 and is correspondingly divided into 3 three test areas (A, B, C), that is, each solution erosion container 5 or the test device corresponds to an independent test partition, and the test partitions A, B, and C of each partition can be subjected to independent erosion or comparison tests. Of course, as the above-mentioned method of testing, different test zones in the same zone are undoubtedly best tested in the same row, so that different ion test solutions of different concentrations can be tested, and whether there is a protective coating or whether dry and wet treatments have been done can be tested, so as to compare and contrast different test results, thereby assisting subsequent analysis. The PCCP protective layer multi-zone independent erosion device can use one PCCP tube to realize the multi-factor influence analysis of ion erosion.

[0069] In the method of use described in the present disclosure, the comparison scheme formulated by S3 is shown in the following Table 1:

[0070] Table 1 - Comparison of multi-factor erosion scenarios Theoretical principles of the present invention: Based on the assumption of a rigid curved cantilever beam, the relationship between the distributed load of the PCCP pipe body 13 and the internal force of the pipe wall section is established to obtain the bending moment and axial force coefficients under the test operation combined load. Based on the flat section assumption, the internal force of the pipe wall section of the PCCP pipe body 13 is calculated, and the moment and axial force equilibrium equations are constructed and the Newton iteration format is constructed to obtain the maximum circumferential strain of the PCCP protective layer simulated under the operation combined load. According to the thick-walled cylinder theory under plane strain problems, in combination with boundary conditions and displacement coordination conditions, the equivalent relationship between the test internal pressure load and the circumferential strain of the protective layer is obtained, forming an equivalent conversion between the test internal pressure and the operation combined load.

[0071] Taking the no-load immersion test as the control group, a multi-zone independent test device is designed on the surface of the protective layer simulated by the PCCP pipe body with the help of the PCCP pipe body 13 and the internal pressure loading machine 16. As shown in Table 1, considering the load, single chloride / sulfate ion corrosion, coupled ion corrosion, ion concentration, dry-wet cycle and surface protection measures, different zones are divided, and the test device is divided into different test areas within the zone to carry out prototype test research on ion corrosion under long-term high internal pressure. After the test is carried out, a specific time is selected to measure the depth and concentration of the ion corrosion protective layer to explore the time-varying law of the ion corrosion protective layer.

[0072] Based on the theory of non-steady-state diffusion, a time-varying model of ion diffusion under long-term high working pressure is proposed, the undetermined coefficients of the partial differential equation are fitted and the surface ion concentration and ion diffusion coefficient are obtained, and the exponential function and power function are constructed to reflect the time-varying law of the surface ion concentration and ion diffusion coefficient, forming an ion diffusion time-varying model. On the basis of the study of the single ion corrosion law under saturated state, combined with the analysis of no-load immersion test data, the influence of load, ion type (single and coupled), ion concentration, dry-wet cycle and surface protection measures on the time-varying law of surface ion concentration and ion diffusion coefficient is explored, and finally a unified time-varying law characterization function is formed based on the results obtained by the use method.

[0073] In summary, through the unique design of the present disclosure, the present disclosure avoids the problem of low load level caused by the brittleness and discreteness of concrete in ion corrosion tests under general loads, reflects the high tensile strain characteristics of the PCCP protective layer, realizes the study of ion corrosion characteristics under long-term real loads and multiple factors, and more accurately reveals the time-varying law of ion corrosion PCCP protection. The present disclosure uses a no-load immersion test as a control group, and with the help of PCCP internal pressure loading equipment, designs multi-partitioned independent ion corrosion devices on the surface of the protective layer, and can consider load, single chloride / sulfate ion corrosion, coupled ion corrosion, ion concentration, dry-wet cycle and surface protection measures to carry out prototype test research on ion corrosion under long-term high internal pressure.

[0074] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for using a PCCP protective layer test device for simulating ion corrosion, characterized in that: The following steps are involved: S1. Divide the area: select a test object for simulating the PCCP protective layer, first divide the test object into 4 partitions, namely, partition I, partition II, partition III, and partition IV; then divide each partition into 3 test areas, namely, test area A, test area B, and test area C; S2 formulates a test plan: the partition I performs a comparison of sulfate ion corrosion with different concentrations, the partition II performs a comparison of chloride ion corrosion with different concentrations, the partition III performs a comparison of different protective measures, and the partition IV performs a mixed comparison test; S3 develops a comparison plan: For the test area A, the test area B, and the test area C in the partition I, respectively, a 1% concentration Na2SO4 solution, a 3% concentration Na2SO4 solution, and a 5% concentration Na2SO4 solution are prepared; Prepare 1% concentration NaCl solution, 3% concentration NaCl solution and 5% concentration NaCl solution for test area A, test area B and test area C in the partition II respectively; For the test area A, the test area B, and the test area C in the partition III, firstly, 5% concentration NaCl solution is prepared respectively, and then protective coating 1, protective coating 2, and protective coating 3 are coated respectively and dry-wet cycle treatment is planned; A 5% NaCl solution, a 5% Na2SO4 solution, and a mixed solution of 5% NaCl and 5% Na2SO4 are respectively prepared for the test area A, the test area B, and the test area C in the partition IV; the test area A and the test area B are respectively planned to be subjected to dry-wet cycle treatment; S4 formulates a dry-wet cycle plan: each test area that is planned to undergo dry-wet cycle treatment is respectively regarded as a separate area to be subjected to dry-wet cycle treatment, and the upper limit of the dry-wet cycle treatment is defined as L times. The number of times the dry-wet cycle treatment is currently performed is defined as Seq, and Seq is initialized to 0, that is, the three test areas A, B, and C in the partition III, and the test areas A and B in the partition IV are respectively regarded as an area to be subjected to dry-wet cycle treatment, and each needs to undergo L dry-wet cycles, and Seq is used to represent the cumulative number of dry-wet cycle treatments that have been performed; S5: equip each test area with a corresponding test device; the test device comprises a solution erosion container (5), the solution erosion container (5) is closely attached to one side of the corresponding test area, and the other side of the test area is soaked in water; S6: performing liquid filling: using the solution configured corresponding to each test area, the solution erosion container (5) corresponding to the test device is filled with liquid until it is full and remains full; S7 executes the wet-dry cycle: for all the wet-dry cycle areas, soak for N days and dry for M days respectively. Specifically, for each test device corresponding to the wet-dry cycle area, firstly, the solution erosion container (5) is filled with the corresponding solution and maintained for N days, i.e., soaking operation; then, the solution in the solution erosion container (5) is discharged, and the wet-dry cycle area and the test device are blown dry and maintained dry for M days, i.e., drying operation; finally, Seq is increased by 1, and the wet-dry operation of this cycle is counted; S8 determines whether the dry-wet cycle should be ended: if Seq=L, it means that the current cumulative number of dry-wet cycles has reached the cycle upper limit, and the dry-wet cycle should be ended, so continue S9; otherwise, it means that all dry-wet cycle processing has not been completed, so return to S6; S9 extracting samples: after waiting time T, selecting a number of the test areas, and then extracting a number of core samples; S10 Result Analysis: All the core samples were processed into slices respectively; each slice of the core sample was ground, the chloride ion concentration was determined by titration, the sulfate ion concentration was measured by weighing, and a curve of the concentration of ions intruding into the core sample versus depth was drawn to compare the test results of different partitions.

2. The method of use according to claim 1, characterized in that: The slice thickness is preferably 3 mm.

3. The method of use according to claim 1, characterized in that: In S7, N=2, M=1, which means that each dry-wet cycle treatment requires 2 days of soaking and 1 day of drying respectively.

4. The method of use according to claim 1, characterized in that: In S5 or S8, L=10, which means that the dry-wet cycle treatment needs to be repeated 10 times.

5. The method of use according to claim 1, characterized in that: In S9, T is 10 days, which means that after the dry-wet cycle treatment, sampling is continued after waiting for 10 days.

6. The method of use according to claim 1, characterized in that: The solution erosion container (5) is provided with a container inner cavity, the container inner cavity is connected downwardly to a solution placement barrel (1) and upwardly to a liquid level display barrel (10), and a liquid extraction hose (11) is connected between the interior of the liquid level display barrel (10) and the interior of the solution placement barrel (1); The front side of the solution erosion container (5) is provided with a plurality of transparent windows (501), and the rear side of the solution erosion container (5) is closely attached to the corresponding test area; The lower end of the liquid extraction hose (11) located inside the solution placement barrel (1) is connected to a water extraction pump (12), and the inner cavity of the container is further connected to a blower (7), through which the dry-wet cycle drying work is participated.

7. The method of use according to claim 6, characterized in that: In S6, for the filling operation of each test area, the corresponding test device performs the following steps: S6.1: Turn on the water pump (12) to extract the solution in the solution storage barrel (1), and the solution flows from bottom to top through the liquid extraction hose (11) into the liquid level display barrel (10) and then into the solution erosion container (5); S6.2: Observe through the liquid level display barrel (10) whether the solution erosion container (5) is full; S6.3: If the solution erosion container (5) is full, turn off the water pump (12); otherwise, return to S6.

1.

8. The method of use according to claim 6, characterized in that: The test object is a PCCP pipe body (13), the partition I, the partition II, the partition III, and the partition IV are all divided on the PCCP pipe body (13), the circumferential surface of the PCCP pipe body (13) is divided into the partition I, the partition II, the partition III, and the partition IV from bottom to top, each of the partitions is divided into three test areas, and each of the test areas is provided with a corresponding test device; Therefore, all the test devices are arranged on the circumferential surface of the PCCP tube body (13), one side surface of all the test areas are located on the outer wall of the PCCP tube body (13) and the other side surface is located on the inner wall of the PCCP tube body (13); and because the solution erosion container (5) is in close contact with the corresponding test area, the solution erosion container (5) is actually in close contact with the outer wall of the PCCP tube body (13); During implementation, the solution erosion container (5) is closely attached to one side of the corresponding test area, and water is injected into the PCCP pipe body (13), thereby achieving that the other side of the test area is soaked in water.

9. The method of use according to claim 8, characterized in that: The PCCP tube body (13) is sleeved on the outside of the steel inner liner (20); a base (2001) is provided at the bottom of the steel inner liner (20); the bottom of the PCCP tube body (13) is in close contact with the top of the base (2001); and the space enclosed between the inner wall of the PCCP tube body (13) and the outer wall of the steel inner liner (20) forms an inner cavity of the tube body; A layered scaffold (15) is set up around the PCCP pipe body (13), and the PCCP pipe body (13) is subdivided into the partition I, partition II, partition III, and partition IV by the scaffold (15); The PCCP pipe body (13) is injected with water by injecting water into the inner cavity of the pipe body.

10. The method of use according to claim 9, characterized in that: The top of the PCCP pipe body (13) is connected to a PCCP pipe exhaust port (14), and the bottom of the PCCP pipe body (13) is connected to an internal pressure loading machine (16) via a water pipe (18), and water is injected into the inner cavity of the pipe body via the internal pressure loading machine (16); The water pipe (18) is provided with an internal water pressure gauge (17), and the internal water pressure gauge (17) continuously monitors the water pressure inside the water pipe (18).

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