Experimental device and durability test method for simulating seawater-accelerated corrosion of rock materials

Abstract

The present invention is applicable to the field of corrosion resistance testing devices and provides an experimental device and durability testing method for simulating seawater-accelerated corrosion of rock materials. The experimental device includes a detection mechanism, a sample mounting unit disposed within the detection mechanism, a concentration control unit connected to the detection mechanism for providing corrosive liquids of varying concentrations, a temperature control unit disposed on the detection mechanism for controlling the temperature of the corrosive liquid, and a liquid circulation unit connected to the detection mechanism for controlling the circulation of the corrosive liquid. This invention aims to address the technical problems of existing experimental devices, which fail to simulate uniform seawater impact on the sample during testing, resulting in a weak accelerated corrosion effect and an inability to conduct real-time durability testing under various complex conditions.

Description

Technical Field

[0001] The invention belongs to the field of corrosion resistance test devices, and in particular relates to an experimental device for simulating seawater accelerated corrosion of rock materials and a durability test method. Background Art

[0002] With the continuous development of underground transportation, undersea tunnels have gradually become a common underground engineering project. The bearing system of undersea tunnels is formed by the interaction of the lining structure and the surrounding rock. Undersea tunnel accidents often occur due to surrounding rock instability and encountering unfavorable geological sections. The strength and stability of the surrounding rock are affected by seawater corrosion: the water-rock interaction softens the rock, and the chemical media in the solution corrode the rock. Under the action of seawater corrosion, the mechanical properties of the rock, such as strength, deformation, and durability, deteriorate, resulting in a decline in the engineering performance of the rock mass, threatening the safety and service life of the undersea tunnel. Therefore, the mechanical, deformation, and failure characteristics of the surrounding rock of undersea tunnels are key issues affecting the safety of engineering construction and the longevity of operation. However, due to the inadequate understanding of the physical and chemical damage mechanisms of rock under seawater corrosion and the lack of a rock damage evaluation system under seawater corrosion, it is particularly important to conduct research on the dynamic fatigue failure mechanism of rock under seawater corrosion.

[0003] Real-world seawater erosion of tunnel surrounding rock is characterized by a prolonged effect and limited short-term effects. Therefore, in testing environments, measures to accelerate seawater erosion are necessary to shorten the testing period and thus expedite the testing process. Numerous factors influence the rate of seawater erosion, including temperature and ion concentration. However, in general, the corrosive environment of rock is not the result of a single corrosive factor, but rather the combined effects of multiple factors.

[0004] Concrete buildings and structures that are more common in marine engineering also face the same research difficulties.

[0005] Currently, most patents related to accelerating seawater corrosion use heating, increasing ion concentration, and designing physical devices to simulate ocean wave motion to accelerate corrosion. These physical devices, such as propellers and blades, only achieve a simple simulation of ocean wave motion. Furthermore, most specimens are static or fixed on a sample holder, so the impact of seawater on the specimens is often uneven and incomplete. Consequently, the accelerated corrosion effect is limited, making it difficult to conduct durability tests under various complex conditions.

[0006] Therefore, it is necessary to innovate and improve the existing experimental equipment for accelerated corrosion experiments to solve the existing technical difficulties. Summary of the Invention

[0007] The purpose of the present invention is to provide an experimental device and a durability testing method for simulating seawater accelerated corrosion of rock materials, aiming to solve the technical problems that the experimental devices in the prior art cannot simulate the uniform impact of seawater on the sample during the test, resulting in an unobvious accelerated corrosion effect and an inability to carry out real-time durability testing under various complex conditions.

[0008] The present invention is implemented as follows: an experimental device simulating seawater accelerated corrosion of rock materials includes a detection mechanism, a sample installation unit arranged inside the detection mechanism, a concentration control unit connected to the detection mechanism for providing corrosive liquids of different concentrations, a temperature control unit arranged on the detection mechanism for controlling the temperature of the corrosive liquid, and a liquid circulation unit connected to the detection mechanism for controlling the circulation of the corrosive liquid.

[0009] A further technical solution of the present invention is that the detection mechanism includes a base with a cavity structure, an outer cylinder arranged on the base, a top cover covering the outer cylinder, a first wheel rail arranged on the outer ring of the bottom of the outer cylinder, a first toothed disc arranged on the first wheel rail and having internal meshing teeth, a second wheel rail arranged on the bottom of the outer cylinder and positioned inside the first wheel rail, a second toothed disc arranged on the second wheel rail and having internal and external meshing teeth, a third wheel rail arranged on the outer ring of the top cover opposite to the first wheel rail, a third toothed disc arranged on the third wheel rail and having internal meshing teeth, a fourth wheel rail arranged on the top cover opposite to the second wheel rail, a fourth toothed disc arranged on the fourth wheel rail and having internal and external meshing teeth, a first inner cylinder arranged on the first toothed disc and capable of being engaged with the third toothed disc at its top, a second inner cylinder arranged on the second toothed disc and capable of being engaged with the fourth toothed disc, having a plurality of through holes in its wall and a plurality of blades on its inner side, and a power unit arranged between the first toothed disc and the second toothed disc or between the third toothed disc and the fourth toothed disc.

[0010] A further technical solution of the present invention is: the power unit includes a bracket arranged at the bottom of the outer cylinder or the top of the top cover, a servo motor arranged on the bracket and with a power shaft passing through the bottom of the outer cylinder or the top of the top cover, and a power gear arranged on the power shaft of the servo motor and engaged with the first gear disc and the second gear disc or engaged with the third gear disc and the fourth gear disc.

[0011] A further technical solution of the present invention is that the detection mechanism further includes at least one axle arranged at the bottom of the outer cylinder, and an internal shaft gear arranged on the axle and meshing with the second gear disc through meshing gears for mounting the sample mounting unit.

[0012] A further technical solution of the present invention is: the detection mechanism also includes a first pipeline provided in the base with an electric-controlled liquid valve for connecting the concentration control unit and the outer cylinder, and the outlet is placed between the first gear disc and the second gear disc, a second pipeline and a third pipeline provided in the base with an electric-controlled liquid valve for connecting the liquid circulation unit and the outer cylinder, and the outlet is placed between the first gear disc and the second gear disc, and a power supply for connecting the power unit and the electric-controlled liquid valve.

[0013] A further technical solution of the present invention is that the detection mechanism further includes an inner fixed shaft arranged at the center of the bottom of the outer cylinder for supporting the top cover.

[0014] A further technical solution of the present invention is: the detection mechanism also includes at least one first rotating gear arranged between the first toothed disc and the second toothed disc and meshing with the first toothed disc and the second toothed disc, and a second rotating gear arranged between the third toothed disc and the fourth toothed disc and meshing with the third toothed disc and connected by a connecting rod for limiting the position and ensuring synchronous rotation.

[0015] A further technical solution of the present invention is: the concentration control unit includes a corrosive solution generator for generating corrosive solutions of different concentrations, and a first connecting pipe connecting the corrosive solution generator and the first pipeline.

[0016] A further technical solution of the present invention is: the temperature control unit includes at least one heating rod arranged between the first gear disc and the second gear disc and connected to the power supply for heating the corrosive liquid, and at least one refrigeration tube arranged between the first gear disc and the second gear disc and connected to the power supply for cooling the corrosive liquid.

[0017] A further technical solution of the present invention is: the liquid circulation unit includes a liquid storage tank connected to the third pipeline through a third connecting pipe and with a harmful gas processor installed inside, and a pressure water tank connected to the second pipeline through a second connecting pipe and connected to the liquid storage tank through a fourth connecting pipe; the detection mechanism also includes a pressure gauge for monitoring the first pipeline, the second pipeline and the third pipeline; the detection mechanism also includes at least one temperature sensor arranged on the inner wall of the outer cylinder, connected to an external data monitoring machine and electrically connected to the power supply, and at least one ion concentration sensor arranged on the inner wall of the outer cylinder, connected to an external data monitoring machine and electrically connected to the power supply; the sample installation unit includes a base body for installation on the inner shaft gear, and a threaded column arranged on the base body and with an external thread for fixing the sample.

[0018] A further technical solution of the present invention is that the detection mechanism also includes a small point load testing machine provided on the sample and equipped with a stress sensor.

[0019] Another object of the present invention is to provide a durability testing method for an experimental device simulating seawater accelerated corrosion of rock materials, the durability testing method comprising the following steps:

[0020] Step S1: while accelerating corrosion in the experimental device, a point load test is performed, and a stress sensor is installed on a small corrosion-resistant point load testing machine, and a temperature sensor and an ion concentration sensor are used to achieve simultaneous accelerated corrosion and point load testing and real-time monitoring;

[0021] Step S2: Through point load test, a fixed target load is applied using a small point load tester under the monitoring of the stress sensor. P , obtain the point load intensity of the small point load tester under the corrosive solution and the time from the beginning of corrosion to the destruction of the sample, and then conduct a calibration study on the relationship between the durability of the sample and the ion concentration and corrosion time;

[0022] Step S3: The point load strength and uniaxial compressive strength conversion formula is used to convert the sample uniaxial compressive strength under different corrosive solutions with the corrosion time and solution concentration, and the fatigue strength or fatigue life evolution of the sample under the coupling of different corrosion environments and loads is obtained.

[0023] A further technical solution of the present invention is: the specific steps of step S2 are to apply pressure to the loading system outside the device through an external hydraulic pipeline, start the small point load testing machine inside the device, load the target point load value, and keep the load constant. The stress sensor on the small point load testing machine enables the data monitoring machine outside the detection mechanism to display the real-time stress size of the small point load testing machine. When the final point load stress value suddenly drops to zero, it indicates that the sample is damaged. The duration and the applied damage load stress are recorded, and by repeating the experiment continuously, the relationship between the initial applied load stress and the durability time and the ion concentration of the corrosion solution is obtained, thereby calibrating the relationship between the durability of the sample and the ion concentration and corrosion time.

[0024] The present invention has the beneficial effects of enabling the specimen and the detection mechanism to rotate in opposite directions and controlling their rotational speed, significantly increasing the contact area per unit time between the specimen and the corrosive solution, accelerating ion diffusion and thereby accelerating the corrosion rate of the specimen. This helps shorten the response time of the durability test and further addresses the problem of long corrosion durability test cycles and insignificant short-term results. Furthermore, fan blades with inclined cross sections are evenly mounted around the inner wall of the second inner cylinder. Driven by power, the fan blades rotate with the second inner cylinder, promoting the flow of corrosive solution within the second inner cylinder. The base is fixed to the inner shaft gear by an interlocking manner, and the specimen is directly mounted on a threaded column made of plastic material, effectively preventing the specimen from repeated scratching and local damage. Furthermore, the numerical relationship between ion concentration and time measured by the ion concentration sensor can be used to calibrate the relationship between the corrosion degree of rock or concrete specimens and the ion concentration before and after corrosion and the corrosion time. Alternatively, other monitoring methods, such as a corrosion-resistant small point load tester, can be installed on the specimen to monitor the entire dynamic erosion and damage process of the specimen in real time, enabling the simultaneous performance of accelerated corrosion and point load testing. By converting the point load strength and uniaxial compression strength conversion formula, we can obtain the variation law of the uniaxial compression strength of the sample under different corrosive solutions with corrosion time and solution concentration, as well as the fatigue strength or fatigue life evolution law of the sample under different corrosion environments and load coupling, so as to carry out more in-depth research on the corrosion mechanical response of rock or concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 2. It is a structural diagram of an experimental device for simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention;

[0026] Figure 2 This is a planar structural diagram of an experimental device for simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention;

[0027] Figure 3 This is a diagram showing the base structure of an experimental device for simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention;

[0028] Figure 4 This is an exploded view of a detection mechanism of an experimental device for simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention;

[0029] Figure 5 This is an installation diagram of a small point load testing machine for an experimental device simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention;

[0030] Figure 6 This is a graph showing the relationship between the initial applied load and durability time and the ion concentration of the corrosion solution in a durability testing method of an experimental device simulating accelerated seawater corrosion of rock materials provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] Reference numerals: 1-detection mechanism 2-sample mounting unit 3-concentration control unit 4-temperature control unit 5-liquid circulation unit 6-base 7-outer cylinder 8-top cover 9-first wheel rail 10-first gear disc 11-second wheel rail 12-second gear disc 13-third gear disc 14-fourth gear disc 15-first inner cylinder 16-fan blade 17-second inner cylinder 18-power unit 19-power gear 20-axle 21-meshing gear 22-inner shaft gear 23-electrically controlled liquid valve 24-first pipeline 25-second pipeline 26- The third pipeline 27-power supply 28-internal fixed shaft 29-first rotating gear 30-connecting rod 31-second rotating gear 32-corrosive solution generator 33-first connecting pipe 34-heating rod 35-refrigeration pipe 36-liquid storage tank 37-pressure water tank 38-third connecting pipe 39-second connecting pipe 40-fourth connecting pipe 41-pressure gauge 42-base body 43-threaded column 44-small point load testing machine 45-sample 46-harmful gas processor 47-electro-hydraulic servo control loading system 48-hydraulic pipeline.

[0032] Figure 1-5 The present invention provides an experimental device for simulating seawater-accelerated corrosion of rock materials. The experimental device includes a detection mechanism 1, a sample installation unit 2 arranged inside the detection mechanism 1, a concentration control unit 3 connected to the detection mechanism 1 for providing corrosive liquids of different concentrations, a temperature control unit 4 arranged on the detection mechanism 1 for controlling the temperature of the corrosive liquid, and a liquid circulation unit 5 connected to the detection mechanism 1 for controlling the circulation of the corrosive liquid.

[0033] The detection mechanism 1 includes a base 6 with a cavity structure, an outer cylinder 7 arranged on the base 6, a top cover 8 covering the outer cylinder 7, a first wheel rail 9 arranged on the outer ring of the bottom of the outer cylinder 7, a first toothed disc 10 arranged on the first wheel rail 9 and having internal meshing teeth, a second wheel rail 11 arranged on the bottom of the outer cylinder 7 and placed on the inner side of the first wheel rail 9, a second toothed disc 12 arranged on the second wheel rail 11 and having internal and external meshing teeth, a third wheel rail (not shown in the figure) arranged on the outer ring of the top cover 8 and opposite to the first wheel rail 9, and a third toothed disc 12 arranged on the third wheel rail and having internal meshing teeth. a disc 13, a fourth wheel rail (not shown in the figure) arranged on the top cover 8 and opposite to the second wheel rail 11, a fourth gear disc 14 arranged on the fourth wheel rail and having internal and external meshing teeth, a first inner cylinder 15 arranged on the first gear disc 10 and capable of being engaged with the third gear disc 13 at the top, a second inner cylinder 17 arranged on the second gear disc 12 and capable of being engaged with the fourth gear disc 14 at the top, having a plurality of through holes in the cylinder wall and a plurality of fan blades 16 on the inside, and a power unit 18 arranged between the first gear disc 10 and the second gear disc 12 or between the third gear disc 13 and the fourth gear disc 14.

[0034] The power unit 18 includes a bracket (not shown in the figure) arranged at the bottom of the outer cylinder 7 or the top of the top cover 8, a servo motor (not shown in the figure) arranged on the bracket and with a power shaft passing through the bottom of the outer cylinder 7 or the top of the top cover 8, and a power gear 19 arranged on the power shaft of the servo motor and engaged with the first gear disc 10 and the second gear disc 12 or engaged with the third gear disc 13 and the fourth gear disc 14.

[0035] The detection mechanism 1 further includes at least one axle 20 disposed at the bottom of the outer cylinder 7 , and an inner shaft gear 22 disposed on the axle 20 and meshing with the second toothed disc 12 via a meshing gear 21 for mounting the sample mounting unit 2 .

[0036] The detection mechanism 1 also includes a first pipeline 24 provided in the base 6 with an electric-controlled liquid valve 23 for connecting the concentration control unit 3 and the outer cylinder 7, with the outlet located between the first gear disc 10 and the second gear disc 12; a second pipeline 25 and a third pipeline 26 provided in the base 6 with an electric-controlled liquid valve 23 for connecting the liquid circulation unit 5 and the outer cylinder 7, with the outlet located between the first gear disc 10 and the second gear disc 12; and a power supply 27 for connecting the power unit 18 and the electric-controlled liquid valve 23.

[0037] The detection mechanism 1 further includes an inner fixed shaft 28 disposed at the bottom center of the outer cylinder 7 for supporting the top cover 8 .

[0038] The detection mechanism 1 also includes at least one first rotating gear 29 arranged between the first toothed disc 10 and the second toothed disc 12 and meshing with the first toothed disc 10 and the second toothed disc 12, and a second rotating gear 31 arranged between the third toothed disc 13 and the fourth toothed disc 14 and meshing with the third toothed disc 13 and the fourth toothed disc 14 and connected by a connecting rod 30 for limiting the position and ensuring synchronous rotation.

[0039] The concentration control unit 3 includes a corrosion solution generator 32 for generating corrosion solutions of different concentrations, and a first connecting pipe 33 connecting the corrosion solution generator 32 and the first pipeline 24 .

[0040] The temperature control unit 4 includes at least one heating rod 34 arranged between the first gear disc 10 and the second gear disc 12 and connected to the power supply 27 for heating the corrosive liquid, and at least one cooling tube 35 arranged between the first gear disc 10 and the second gear disc 12 and connected to the power supply 27 for cooling the corrosive liquid.

[0041] The liquid circulation unit 5 includes a liquid reservoir 36 connected to the third pipeline 26 via a third connecting pipe 38 and having a harmful gas processor 46 installed therein, and a pressure water tank 37 connected to the second pipeline 25 via a second connecting pipe 39 and to the liquid reservoir 36 via a fourth connecting pipe 40. The detection mechanism 1 also includes a pressure gauge 41 for monitoring the first pipeline 24, the second pipeline 25, and the third pipeline 26. The detection mechanism 1 also includes at least one temperature sensor (not shown) disposed on the inner wall of the outer cylinder 7 and connected to an external data monitoring device and electrically connected to the power supply 27, and at least one ion concentration sensor (not shown) disposed on the inner wall of the outer cylinder 7 and connected to an external data monitoring device and electrically connected to the power supply 27. The sample mounting unit 2 includes a base body 42 for mounting on the internal shaft gear 28, and a threaded column 43 disposed on the base body 42 and having external threads for fixing the sample 45. The detection mechanism 1 also includes a small point load tester 44 disposed on the sample 45 and having a stress sensor (not shown). Temperature sensors and ion concentration sensors are used to monitor environmental parameters within the cylinder in real time. The ambient temperature and ion concentration of the corrosion solution are adjusted. Under the accelerated corrosion effect of the device rotating in opposite directions, data collected by the ion concentration sensor is imported into an external data monitoring machine. Using the numerical relationship between the measured ion concentration after corrosion and time, the relationship between the degree of corrosion of rock or concrete specimens and the ion concentration before and after corrosion, as well as the corrosion time, is studied. The ion concentration, monitored in real time at multiple points, is used as a response indicator of the degree of corrosion, thereby quantitatively characterizing the degree of sandstone corrosion.

[0042] A durability testing method for an experimental device simulating seawater accelerated corrosion of rock materials, the durability testing method comprising the following steps:

[0043] Step S1: While the experimental device is accelerating corrosion, a point load test is performed. A stress sensor is installed on the corrosion-resistant small point load tester 44, and other sensors such as temperature sensors and ion concentration sensors are used to achieve simultaneous accelerated corrosion and point load testing and real-time monitoring.

[0044] Step S2: Through point load test, a fixed target load is applied by using a small point load tester 44 under the monitoring of the stress sensor. P , obtain the point load intensity of the small point load tester 44 under the corrosive solution and the time from the beginning of corrosion to the destruction of the sample, and then conduct a calibration study on the relationship between the durability of the sample 45 and the ion concentration and corrosion time;

[0045] Step S3: Convert using the point load strength and uniaxial compression strength conversion formula:

[0046] First, the point load intensity index is calculated as follows:

[0047]

[0048] Where, is the uncorrected point load intensity index; —Equivalent diameter of the specimen (mm), —The maximum load at which the specimen fails (N).

[0049] The International Society of Rock Mechanics uses the strength index value of the radial loading point load test of a cylindrical specimen with a diameter of 50 mm as Determined as standard test value.

[0050] For standard specimens, the conversion method between uniaxial compressive strength and point load strength index is:

[0051]

[0052] Where, ——Empirical parameters. The value range is generally 22.8~23.7

[0053] For non-standard specimens, Make corrections:

[0054]

[0055] The variation law of uniaxial compressive strength of rock or concrete with corrosion time and solution concentration under different corrosion solutions can be obtained, as well as the evolution law of fatigue strength or fatigue life of rock or concrete under the coupling of different corrosion environments and loads.

[0056] During operation, the electrically controlled liquid valve 23 on the first pipeline 24 is opened, and the corrosive solution of the set concentration is discharged from the corrosive solution generator 32 and introduced into the detection mechanism 1 through the first pipeline 24. After the detection mechanism 1 is filled, the electrically controlled liquid valve 23 on the first pipeline 24 is closed. When the ambient temperature of the solution in the detection mechanism 1 needs to be increased, the heating rod 34 is started to heat the detection mechanism 1 to the target temperature; when the ambient temperature of the solution in the detection mechanism 1 needs to be lowered, the refrigeration pipe 35 is started to cool the detection mechanism 1 to the target temperature. When the ambient ion concentration of the solution in the detection mechanism 1 needs to be adjusted, the concentration control unit 3 and the liquid circulation unit 5 are activated in coordination, and the concentration is changed by controlling the corrosive solution generator 32 and the pressure water tank 37 through the electrically controlled liquid valves 23 on the first pipeline 24, the second pipeline 25 and the third pipeline 26. At the same time, the corrosive solution is recycled and reused after each test using the liquid storage tank 36 in the liquid circulation unit 5.

[0057] The real-time parameters of the environmental factors of the accelerated corrosion test are collected by the temperature sensor and the ion concentration sensor and then transmitted to the external data monitoring machine, and the solution environment in the detection mechanism 1 is controlled by the data monitoring machine.

[0058] A cylindrical sandstone specimen 45 was placed in a simulated seawater environment. The ambient temperature and ion concentration of the corrosive solution were adjusted. Under the accelerated corrosion effect of the counter-rotating detection mechanism 1, data was collected by the ion concentration sensor and imported into an external data monitoring device. Using the numerical relationship between the measured ion concentration after corrosion and time, a calibration relationship between the corrosion degree of the sandstone specimen 45 and the ion concentration before and after corrosion, as well as the corrosion time, was studied. The average of the ion concentrations monitored in real time at multiple points was used as a corrosion indicator to quantitatively characterize the degree of sandstone corrosion.

[0059] When conducting a point load test, a corrosion-resistant small point load tester 44 is installed on the sample 45 so that the loading head of the small point load tester 44 is always in contact with the same point on the surface of the sample 45. The sample 45 is subjected to a point load test. The hydraulic pipeline 48 is externally connected, and the electro-hydraulic servo-controlled loading system 47 is used to apply pressure outside the device to start the small point load tester 44 inside the device, load the target point load value, and keep the load at a constant value. A stress sensor is installed on the small point load tester 44 so that the real-time stress of the small point load tester 44 in the cylinder can be displayed on the data monitoring machine outside the detection mechanism 1. When the final point load stress value suddenly drops to zero, it indicates that the sample 45 is damaged. The duration and the applied damage load are recorded, and the relationship between the initial applied load and the durability time and the ion concentration of the corrosion solution is obtained by repeating the experiment (such as Figure 6 As shown in Figure 45, the relationship between the durability of sandstone sample 45 and ion concentration and corrosion time was calibrated.

[0060] This experimental device enables the specimen and the detection mechanism to rotate in opposite directions and control their rotation speed. This significantly increases the contact area per unit time between the specimen and the corrosive solution, accelerating ion diffusion and, therefore, the corrosion rate of the specimen, which helps shorten the response time of the durability test and further addresses the problem of long corrosion durability test cycles and insignificant short-term results. Simultaneously, fan blades with inclined cross sections are evenly mounted around the inner wall of the second inner cylinder. Driven by power, the fan blades rotate with the second inner cylinder, promoting the flow of corrosive solution within the second inner cylinder. The base is fixed to the inner shaft gear by a chiseled mechanism, and the specimen is directly mounted on a threaded post made of plastic, effectively preventing the specimen from repeated scratching and local damage. In addition, the numerical relationship between ion concentration and time measured by the ion concentration sensor can be used to calibrate the relationship between the corrosion degree of rock or concrete specimens and the ion concentration and corrosion time before and after corrosion. Other monitoring methods, such as a corrosion-resistant small point load tester, can also be installed on the specimen to monitor the entire dynamic erosion and damage process of the specimen in real time, enabling the simultaneous conduct of accelerated corrosion and point load testing. By converting the point load strength and uniaxial compression strength conversion formula, we can obtain the variation law of the uniaxial compression strength of the sample under different corrosive solutions with corrosion time and solution concentration, as well as the fatigue strength or fatigue life evolution law of the sample under different corrosion environments and load coupling, so as to carry out more in-depth research on the corrosion mechanical response of rock or concrete.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An experimental device for simulating seawater-accelerated corrosion of rock materials, characterized by: The experimental device includes a detection mechanism, a sample installation unit arranged inside the detection mechanism, a concentration control unit connected to the detection mechanism for providing corrosive liquids of different concentrations, a temperature control unit arranged on the detection mechanism for controlling the temperature of the corrosive liquid, and a liquid circulation unit connected to the detection mechanism for controlling the circulation of the corrosive liquid; the detection mechanism includes a base with a cavity structure, an outer cylinder arranged on the base, a top cover covering the outer cylinder, a first wheel rail arranged on the outer ring of the bottom of the outer cylinder, a first toothed disc with internal meshing teeth arranged on the first wheel rail, a second wheel rail arranged on the bottom of the outer cylinder and placed inside the first wheel rail, and a top cover arranged on the second wheel rail. a second toothed disc with internal and external meshing teeth, a third wheel rail arranged on the outer ring of the top cover opposite to the first wheel rail, a third toothed disc with internal meshing teeth arranged on the third wheel rail, a fourth wheel rail arranged on the top cover opposite to the second wheel rail, a fourth toothed disc with internal and external meshing teeth arranged on the fourth wheel rail, a first inner cylinder arranged on the first toothed disc and capable of being engaged with the third toothed disc at the top, a second inner cylinder arranged on the second toothed disc and capable of being engaged with the fourth toothed disc at the top, having a plurality of through holes in the cylinder wall and a plurality of fan blades on the inside, and a power unit arranged between the first toothed disc and the second toothed disc or between the third toothed disc and the fourth toothed disc.

2. The experimental device according to claim 1, characterized in that The power unit includes a bracket arranged at the bottom of the outer cylinder or the top of the top cover, a servo motor arranged on the bracket and with a power shaft passing through the bottom of the outer cylinder or the top of the top cover, and a power gear arranged on the power shaft of the servo motor and engaged with the first gear disc and the second gear disc or engaged with the third gear disc and the fourth gear disc.

3. The experimental device according to any one of claims 1-2, characterized in that: The detection mechanism further includes at least one axle arranged at the bottom of the outer cylinder, and an inner shaft gear arranged on the axle and meshing with the second gear disc through meshing gears for mounting the sample mounting unit.

4. The experimental device according to claim 3, characterized in that The detection mechanism also includes a first pipeline provided in the base with an electric-controlled liquid valve for connecting the concentration control unit and the outer cylinder, with the outlet located between the first gear disc and the second gear disc; a second pipeline and a third pipeline provided in the base with an electric-controlled liquid valve for connecting the liquid circulation unit and the outer cylinder, with the outlet located between the first gear disc and the second gear disc; and a power supply for connecting the power unit and the electric-controlled liquid valve.

5. The experimental device according to claim 4, characterized in that: The detection mechanism further includes an inner fixed shaft arranged at the center of the bottom of the outer cylinder for supporting the top cover.

6. The experimental device according to claim 5, characterized in that The detection mechanism also includes at least one first rotating gear arranged between the first toothed disc and the second toothed disc and meshing with the first toothed disc and the second toothed disc, and a second rotating gear arranged between the third toothed disc and the fourth toothed disc and meshing with the third toothed disc and connected by a connecting rod for limiting the position and ensuring synchronous rotation.

7. The experimental device according to claim 6, characterized in that The concentration control unit includes a corrosive solution generator for generating corrosive solutions with different concentrations, and a first connecting pipe connecting the corrosive solution generator and the first pipeline.

8. The experimental device according to claim 7, characterized in that: The temperature control unit includes at least one heating rod arranged between the first gear disc and the second gear disc and connected to the power supply for heating the corrosive liquid, and at least one refrigeration tube arranged between the first gear disc and the second gear disc and connected to the power supply for cooling the corrosive liquid.

9. The experimental device according to claim 8, characterized in that The liquid circulation unit includes a liquid storage tank connected to the third pipeline through a third connecting pipe and with a harmful gas processor installed inside, and a pressure water tank connected to the second pipeline through a second connecting pipe and connected to the liquid storage tank through a fourth connecting pipe; the detection mechanism also includes a pressure gauge for monitoring the first pipeline, the second pipeline and the third pipeline; the detection mechanism also includes at least one temperature sensor arranged on the inner wall of the outer cylinder, connected to an external data monitoring machine and electrically connected to the power supply, and at least one ion concentration sensor arranged on the inner wall of the outer cylinder, connected to an external data monitoring machine and electrically connected to the power supply; the sample installation unit includes a base body for installation on the inner shaft gear, and a threaded column arranged on the base body and with an external thread for fixing the sample.

10. The experimental device according to claim 9, characterized in that: The detection mechanism also includes a small point load testing machine which is arranged on the sample and has a stress sensor.

11. A method for testing the durability of an experimental device simulating seawater accelerated corrosion of rock materials, comprising the experimental device according to claim 10, characterized in that: The durability testing method comprises the following steps: Step S1: while accelerating corrosion in the experimental device, a point load test is performed, and a stress sensor is installed on a small corrosion-resistant point load testing machine, and a temperature sensor and an ion concentration sensor are used to achieve simultaneous accelerated corrosion and point load testing and real-time monitoring; Step S2: Through a point load test, a fixed target load P is applied using a small point load tester under the monitoring of a stress sensor. The point load intensity of the small point load tester and the time from the onset of corrosion to sample failure in the corrosive solution are obtained, thereby studying the calibration relationship between sample durability, ion concentration, and corrosion time. Step S3: The point load strength and uniaxial compressive strength conversion formula is used to convert the sample uniaxial compressive strength under different corrosive solutions with the corrosion time and solution concentration, and the fatigue strength or fatigue life evolution of the sample under the coupling of different corrosion environments and loads is obtained.

12. The durability testing method according to claim 11, characterized in that: The specific steps of step S2 are to apply pressure to the loading system outside the device by using an external hydraulic pipeline, start the small point load tester inside the device, load the target point load value, and keep the load constant. The stress sensor on the small point load tester enables the data monitoring machine outside the detection mechanism to display the real-time stress of the small point load tester. When the final point load stress value suddenly drops to zero, it indicates that the sample is damaged. The duration and the applied damage load stress are recorded. By repeating the experiment continuously, the relationship between the initial applied load stress and the durability time and the ion concentration of the corrosion solution is obtained, thereby calibrating the relationship between the durability of the sample and the ion concentration and corrosion time.

Images