A device for testing the performance of well wall concrete

Abstract

This invention provides a device for testing the performance of well wall concrete, comprising a hollow housing divided from back to front into a rear chamber and a front chamber. The front chamber is further divided into a pressurization zone and a corrosion zone. The pressurization zone accommodates a cubic well wall concrete sample and contains multiple movable pressure blocks with flat inner surfaces. A heater is located in the rear chamber, with its front surface conforming to the rear surface of the well wall concrete sample. A nozzle is located in the corrosion zone, with the front surface of the well wall concrete sample positioned within the nozzle's spray range. A heat insulation plate is installed between the rear and front chambers. This testing device comprehensively and realistically simulates the multi-directional pressure, temperature difference, and corrosive environment faced by well wall concrete in actual engineering projects, filling the gaps in existing concrete testing devices for multi-factor coupled simulation and providing a powerful tool for in-depth research on the performance changes of well wall concrete under complex working conditions.

Description

Technical Field

[0001] This invention relates to the field of concrete, and in particular to the field of concrete testing technology, specifically to a device for testing the performance of well wall concrete. Background Technology

[0002] In deep well mining and underground engineering construction, wellbore concrete faces extremely complex and harsh working environments. On the one hand, the immense pressure deep underground acts on the wellbore concrete from all directions; on the other hand, due to geothermal gradients within the formation and localized cooling during engineering operations, the wellbore concrete experiences significant temperature differences between its inner and outer sides. Simultaneously, in some humid and saline environments, the wellbore remains constantly moist, accompanied by groundwater leaching, and the inner wellbore wall is frequently subjected to chemical corrosion. These factors interact and severely affect the mechanical properties, durability, and long-term stability of the wellbore concrete. To study the degradation mechanism and mechanical behavior of wellbore concrete in these complex deep environments, it is necessary to develop appropriate testing equipment.

[0003] In the process of realizing this invention, the inventors discovered at least the following problems in the prior art:

[0004] Existing concrete performance testing equipment can only simulate one or more conditions in a single environment, such as pressure, temperature, or corrosion, without considering the temperature difference between the inside and outside of the well wall concrete. Therefore, it is difficult to comprehensively and realistically reproduce the complex working conditions of well wall concrete and cannot meet the needs of performance research on well wall concrete under the coupled effects of multiple factors. Thus, how to comprehensively and realistically simulate the complex working conditions of well wall concrete in actual engineering projects, thereby ensuring the accuracy of test results and providing a reference for the long-term safety and stability of deep well concrete, is a problem that needs to be solved. Summary of the Invention

[0005] This invention provides a device for testing the performance of well wall concrete, particularly a device for testing the performance of well wall concrete under complex environments. It is used to test well wall concrete under deep well or complex geological conditions (e.g., underground mines in coal mines and non-coal mines where the mine water contains high concentrations of corrosive ions; for example, a gold mine in Shandong is currently constructing a 2500-meter ultra-deep vertical shaft, where the well wall concrete is corroded and damaged to a certain extent under high temperature and high stress due to the influence of mine water containing high concentrations of ions). It can perform mine safety and environmental monitoring, comprehensively and realistically simulating the complex working conditions of well wall concrete in actual engineering projects, thereby ensuring the accuracy of test results and guaranteeing the safety and reliability of the quality, construction, and performance of mine well wall concrete.

[0006] To achieve the above objectives, embodiments of the present invention provide a well wall concrete performance testing device, comprising a hollow device shell, the device shell being divided into a rear cavity and a front cavity from back to front, the front cavity being divided into a pressurization zone and a corrosion zone from back to front; the pressurization zone is used to accommodate a cubic well wall concrete sample, and multiple movable pressure blocks are arranged in the pressurization zone, the side of the pressure block facing the center of the pressurization zone being a plane; a heater is arranged in the rear cavity, the front side of the heater being able to fit against the rear side of the well wall concrete sample; a nozzle is arranged in the corrosion zone, the front side of the well wall concrete sample being located within the spray range of the nozzle; a heat insulation plate is arranged between the rear cavity and the front cavity, the heat insulation plate having openings for heating the well wall concrete sample.

[0007] Furthermore, four pressure blocks are evenly distributed in the four directions of the pressurization zone: top, bottom, left, and right. Each pressure block is connected to the hydraulic pump through a corresponding hydraulic cylinder. The hydraulic cylinder corresponding to the left pressure block is arranged horizontally, the hydraulic cylinder corresponding to the right pressure block is arranged horizontally, the hydraulic cylinder corresponding to the top pressure block is arranged vertically, and the hydraulic cylinder corresponding to the bottom pressure block is arranged vertically.

[0008] Furthermore, a pressure sensor is provided between the pressure block and the corresponding hydraulic cylinder, and the pressure sensor is a strain gauge force sensor.

[0009] Furthermore, the well wall concrete performance testing device also includes an ultrasonic transmitter, an ultrasonic receiver, and an ultrasonic signal analysis device; an ultrasonic probe is connected to the side of the pressure block facing the center of the pressurized area, and the ultrasonic probe is connected to the ultrasonic transmitter and the ultrasonic receiver respectively, and the ultrasonic signal analysis device is electrically connected to the ultrasonic receiver.

[0010] Furthermore, a groove is provided on the side of the pressure block facing the center of the pressure zone. The volume of the groove is larger than the volume of the ultrasonic probe, and the ultrasonic probe is placed in the groove.

[0011] Furthermore, the heater includes a square outer frame and a long strip of PTC ceramic heating plate connected inside the outer frame, and heat sinks are connected to the side of the PTC ceramic heating plate.

[0012] Furthermore, the well wall concrete performance testing device also includes multiple temperature sensors and a temperature control device. The temperature sensors are connected to the front and rear sides of the well wall concrete sample, respectively, and the temperature control device is electrically connected to the PTC ceramic heating plate.

[0013] Furthermore, a waste liquid collection tank is connected to the bottom of the device housing.

[0014] Furthermore, the nozzle includes an interconnected corrosive liquid inlet and a high-pressure gas inlet. The corrosive liquid inlet is connected to a storage tank containing the corrosive liquid via an inlet pipe, and the high-pressure gas inlet is connected in sequence to a servo controller, a pressure regulating device, and a magnetic pump via an inlet pipe. A flow meter is also installed in the inlet pipe.

[0015] Furthermore, the well wall concrete performance testing device also includes a protective door with an observation window.

[0016] This invention also provides a method for testing the performance of wellbore concrete. This method uses the wellbore concrete performance testing device described above, and includes:

[0017] The device is equipped with a hollow housing, which is divided into a rear cavity and a front cavity from back to front. The front cavity is further divided into a pressurization zone and a corrosion zone from back to front. A well wall concrete sample is placed in the pressurization zone and positioned on the top surface of the pressure block below. A heater is installed in the rear cavity, with its front side able to fit against the rear side of the well wall concrete sample. A nozzle is installed in the corrosion zone, with the front side of the well wall concrete sample within the spray range of the nozzle. A heat insulation plate is installed between the rear cavity and the front cavity.

[0018] The well wall concrete sample is lifted to the predetermined position by the pressure block below, and the predetermined pressure is applied to the well wall concrete sample simultaneously by the four pressure blocks;

[0019] A heater is used to heat the rear side of the well wall concrete sample to a preset temperature, while a nozzle is used to spray a corrosive liquid onto the front side of the well wall concrete sample, thereby creating a temperature difference between the front and rear sides of the well wall concrete sample.

[0020] An ultrasonic probe pre-placed on the side of the well wall concrete sample was used to perform ultrasonic testing on the well wall concrete sample.

[0021] The wellbore concrete performance testing method of the present invention can be performed using the wellbore concrete performance testing device described above.

[0022] The above technical solution has the following beneficial effects:

[0023] In this invention, a heater is used to heat the rear side of the well wall concrete sample, while a corrosive liquid is sprayed onto the front side of the sample. This effectively cools the front side, creating a temperature difference between the front and rear surfaces of the sample. Therefore, this testing device can comprehensively and realistically simulate the multi-directional pressure, front-rear temperature difference, and corrosive environment faced by well wall concrete in actual engineering. It fills the gap in the existing concrete testing devices for multi-factor coupled simulation, ensures the accuracy of the final results, and provides a powerful tool for in-depth research on the performance changes of well wall concrete under complex working conditions.

[0024] In addition, the technical solution of this application also has the following characteristics:

[0025] 1. By adopting a PTC ceramic heating plate combined with heat dissipation and insulation design, the temperature of the rear side of the well wall concrete sample is precisely controlled, and conditions are provided for the effective formation of temperature difference between the front and rear sides of the sample. At the same time, the PTC ceramic heating plate has the advantages of high heating efficiency, good temperature stability and high safety.

[0026] 2. It can precisely control parameters such as the flow rate and spray angle of the corrosive liquid medium, simulate various corrosive environments, and the corrosion product treatment system can meet environmental protection requirements, avoiding environmental pollution during the experiment.

[0027] 3. The hydraulic pressurization system driving the pressure block achieves precise loading and stable maintenance of bidirectional pressure on the well wall concrete sample through multiple sets of high-precision loading devices and advanced control system, which can simulate the bidirectional stress state of well wall concrete under different formation pressure conditions.

[0028] 4. Based on the simulation of the temperature difference between the inside and outside of concrete, this invention realizes the performance testing and service environment simulation of well wall concrete throughout its entire life cycle under multi-directional stress and corrosion environment. It can ensure the quality, construction and performance of well wall concrete through accurate testing, and realize accurate simulation of safety and environmental testing. It is beneficial to the construction and construction of mine quality or mine safety, and to the safe production of energy while ensuring the safety of the environment and ecology. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the lateral structure of a well wall concrete performance testing device according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the forward structure of a well wall concrete performance testing device according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram illustrating the working principle of the nozzle in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the pressurization zone in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram illustrating the working principle of the heater in an embodiment of the present invention;

[0035] Figure 6 This is a diagram showing the arrangement of an ultrasonic probe forming a phased array according to an embodiment of the present invention.

[0036] Reference numerals: 1. Compression block; 2. Well wall concrete sample; 3. Hydraulic control device; 4. Hydraulic cylinder oil pipe; 5. Ultrasonic probe; 6. Corrosion waste liquid; 7. Waste liquid collection tank; 8. Low-pressure oil pipe; 9. Hydraulic pump; 10. High-pressure oil pipe; 11. Hydraulic oil; 12. Nozzle; 13. Discharge port; 14. Heater; 15. Temperature sensor; 16. Magnetic pump; 17. Pressure regulating device; 18. Servo controller; 19. Corrosion inlet; 20. High-pressure air inlet; 21. Corrosion liquid; 24. Heat sink; 25. PTC ceramic heating plate; 26. Heat insulation plate; 100. Rear cavity; 200. Pressurized zone; 300. Corrosion zone. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1 As shown, this embodiment of the invention provides a well wall concrete performance testing device, including a hollow device shell. The device shell is divided from back to front into a rear cavity 100 and a front cavity. The front cavity is further divided from back to front into a pressurization zone 200 and a corrosion zone 300. The pressurization zone 200 is used to accommodate a cubic well wall concrete sample 2, for example, with a length or thickness of 100 mm to ensure sufficient space for simultaneous corrosion and heating tests. Multiple movable pressure blocks 1 are provided within the pressurization zone 200. The side facing the center of the pressurization zone 200 is a plane; a heater 14 is provided in the rear cavity 100, and the front side of the heater 14 can be in contact with the rear side of the well wall concrete sample 2; a nozzle 12 is provided in the corrosion zone 300, and the front side of the well wall concrete sample 2 is located within the spray range of the nozzle 12; a heat insulation plate is provided between the rear cavity 100 and the front cavity, and an opening is provided on the heat insulation plate corresponding to the position of the well wall concrete sample 2, which is used for the heat insulation plate to heat the well wall concrete sample 2.

[0039] To address the aforementioned issues, this technical solution employs a heater 14 located within the rear cavity 100 to heat the rear side of the well wall concrete sample 2 after it is positioned. Simultaneously, a corrosive liquid 21 is sprayed onto the front side of the sample to simulate corrosion. This spraying process also cools the front side of the sample, creating a temperature difference between the front and rear surfaces, which better reflects the actual working conditions of well wall concrete. Furthermore, the pressure blocks 1 within the pressurization zone 200 exert pressure on the well wall concrete sample 2 from all four sides (up, down, left, and right). Therefore, this testing device can comprehensively and realistically simulate the multi-directional pressure, front-to-back temperature difference, and corrosive environment faced by well wall concrete in actual engineering projects. This fills the gap in existing concrete testing devices regarding multi-factor coupled simulation, ensuring the accuracy of the final results and providing a powerful tool for in-depth research on the performance changes of well wall concrete under complex working conditions.

[0040] Meanwhile, a sealing and heat insulation structure needs to be set between the rear chamber 100 and the pressurization zone 200 of the front chamber to prevent mutual interference between the heating system and the hydraulic pressurization system and to ensure the independence and stability of the experimental conditions. Therefore, a heat insulation plate 26 is set between the two chambers. However, the completely sealed heat insulation plate 26 will affect the heater 14 from heating the rear side of the well wall concrete sample 2. Therefore, an opening needs to be set in the middle of the heat insulation plate 26 to heat the rear side of the well wall concrete sample 2.

[0041] Furthermore, such as Figure 2 , Figure 4 As shown, four pressure blocks 1 are evenly distributed in the four directions (up, down, left, and right) within the pressurization zone 200. Each pressure block 1 is connected to a hydraulic pump 9 via a corresponding hydraulic cylinder. The hydraulic cylinder corresponding to the pressure block 1 on the left is horizontally arranged, the hydraulic cylinder corresponding to the pressure block 1 on the right is horizontally arranged, the hydraulic cylinder corresponding to the pressure block 1 on the top is vertically arranged, and the hydraulic cylinder corresponding to the pressure block 1 on the bottom is vertically arranged. When each hydraulic cylinder extends inward simultaneously, each pressure block 1 moves synchronously towards the center of the pressurization zone 200, thereby pressing the well wall concrete sample 2, which has been placed therein, from four directions, achieving uniform pressure on the well wall concrete sample 2 in the left-right direction.

[0042] Furthermore, this invention can also be designed with a dynamic loading function, capable of simulating the impact of dynamic loads such as earthquakes and ground creep on well wall concrete. An electromagnetic vibrator or a hydraulic pulse system can be used to apply periodic or random dynamic forces to the four pressure blocks 1. For example, the four pressure blocks 1 are connected to an electromagnetic vibrator or a hydraulic pulse system. A system that can be designed to automatically adjust the applied pressure according to the development of concrete strength, controlled by a computer or PLC, can be designed. The electromagnetic vibrator or hydraulic pulse system can more accurately simulate the stress conditions of concrete under actual working conditions.

[0043] Furthermore, in the wellbore concrete performance testing device, a pressure sensor is also installed between the pressure block 1 and the corresponding hydraulic cylinder. The pressure sensor is a strain gauge force sensor. Based on the characteristics of the pressurization zone 200, the pressure sensor also includes a horizontal pressure sensor and a vertical pressure sensor; the vertical pressure sensor is located between the pressure block 1 arranged vertically and the corresponding hydraulic cylinder, and is used to monitor longitudinal pressure changes; the horizontal pressure sensor is located between the pressure block 1 arranged horizontally and the corresponding hydraulic cylinder, and is used to monitor lateral pressure changes.

[0044] Furthermore, the well wall concrete performance testing device also includes an ultrasonic transmitter, an ultrasonic receiver, and an ultrasonic signal analysis device; an ultrasonic probe 5 is connected to the side of the pressure block 1 facing the center of the pressurization zone 200, the ultrasonic probe 5 is connected to the ultrasonic transmitter and the ultrasonic receiver respectively, and the ultrasonic signal analysis device is electrically connected to the ultrasonic receiver.

[0045] Multiple ultrasonic probes 5 are set on the surface of the pressure block 1. For example, 16 ultrasonic probes 5 are evenly arranged on each pressure block 1, so that the ultrasonic probes 5 can be in close contact with the corresponding surface of the well wall concrete sample 2 to form an ultrasonic monitoring network. A high-frequency ultrasonic pulse signal is generated by an ultrasonic generator and transmitted to each ultrasonic probe 5 via a signal line, causing it to emit ultrasonic waves into the well wall concrete sample 2. The ultrasonic signal propagates within the concrete sample and, upon encountering internal defects (such as microcracks or voids), interfaces between different media (such as the aggregate-cement paste interface), or areas where material properties have changed due to temperature or pressure variations, phenomena such as reflection, refraction, and scattering occur. The reflected ultrasonic signal is received by the ultrasonic probe 5 and transmitted back to the ultrasonic receiver via the signal line. Then, a data acquisition card converts the analog signal received by the ultrasonic receiver into a digital signal and transmits it to an ultrasonic signal analysis device. In the ultrasonic signal analysis device, dedicated ultrasonic data analysis software uses algorithms to extract and analyze the characteristic parameters of the ultrasonic signal (such as amplitude, frequency, and propagation time), thereby enabling real-time assessment of the development of defects within the well wall concrete sample 2, changes in material homogeneity, and the degree of structural damage caused by factors such as temperature, pressure, and corrosion.

[0046] Furthermore, in order to embed the ultrasonic probe 5 into the pressure block 1 so that the ultrasonic probe 5 does not hinder the normal pressurization effect of the pressure block 1 on the well wall concrete sample 2, a groove can be provided on the side of the pressure block 1 facing the center of the pressurization area 200. The volume of the groove is larger than the volume of the ultrasonic probe 5, and the ultrasonic probe 5 is disposed in the groove.

[0047] Furthermore, such as Figure 5 As shown, the heater 14 includes a square-shaped outer frame and a long strip-shaped PTC ceramic heating plate 25 connected inside the outer frame. Heat sinks 24 are connected to the sides of the PTC ceramic heating plate 25. The outer frame can be made of a special high-temperature resistant ceramic material, while the heat sinks 24 are made of aluminum. The heat sinks 24 effectively increase the heat dissipation area and promptly dissipate the heat generated during the heating process. This heater 14 is designed as... Figure 5 The flat, rectangular frame shape shown, combined with the use of the elongated PTC ceramic heating plate 25, reduces the front-to-back dimensions, effectively saving space. The PTC ceramic heating plate offers stable temperature control: due to the properties of PTC material, the PTC ceramic heating plate maintains relatively stable temperature control during heating, avoiding excessive temperature fluctuations, ensuring stable testing, and reducing the risk of safety accidents.

[0048] Furthermore, the well wall concrete performance testing device also includes multiple temperature sensors 15 and a temperature control device. The temperature sensors 15 are respectively connected to the front and rear sides of the well wall concrete sample 2. For example, three temperature sensors 15 can be installed on each of the front and rear surfaces of the well wall concrete sample 2 to accurately monitor temperature changes. The temperature control device is electrically connected to the PTC ceramic heating plate 25. When the temperature is lower than the set value, the temperature control device increases the power supply of the PTC ceramic heating plate; when it is higher than the set value, it decreases the power to ensure accurate and stable heating temperature. The set target temperature range output by the temperature control device is 20~100℃, and the control accuracy should reach ±1℃. The temperature control device can adopt a PID control algorithm, which can automatically adjust the power supply of the PTC ceramic heating plate according to the preset temperature value and the actual temperature value fed back by the temperature sensor, further ensuring accurate and stable heating temperature.

[0049] In the specific implementation process, the expected temperature of the rear side of the well wall concrete sample 2 is 20℃~80℃, for example: 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃. Simultaneously, the temperature of the corrosive liquid is maintained at 20℃~30℃, for example: 20℃, 25℃, 30℃, so that the temperature difference between the front and rear sides is controlled within 10℃~60℃, for example: 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃. In this invention, the inventors set the above temperatures based on the following considerations: geothermal energy is one of the main factors affecting deep mining, and the geothermal gradient is approximately 3℃ / 100m. When the well depth is less than 1000m, the downhole rock temperature is approximately 30-40℃; when the depth reaches 1000-2000m, the rock temperature can reach 40-60℃. Downhole cooling is mainly achieved through ventilation and water supply, reducing the working environment temperature to 20-30℃. Therefore, the expected temperature of the rear side of the well wall concrete is 20-80℃, the temperature of the corrosive fluid is maintained at 20-30℃, and the temperature difference between the front and rear sides is controlled at 10-60℃.

[0050] Furthermore, a waste liquid collection tank 7 made of corrosion-resistant material is connected to the lower part of the device housing, and a discharge port 13 is set at the bottom of the waste liquid collection tank 7 to discharge the corrosive waste liquid 6 to an external waste liquid treatment system. The waste liquid treatment system first treats the acidic waste liquid using a neutralization and precipitation method, and then removes solid impurities through a filtration device, so that the treated corrosive waste liquid 6 meets environmental emission standards before being discharged or recycled.

[0051] Furthermore, such as Figure 3 As shown, the nozzle 12 includes an interconnected corrosive liquid inlet 19 and a high-pressure gas inlet 20. The corrosive liquid inlet 19 is connected to a storage tank containing corrosive liquid 21 via an inlet pipe. The high-pressure gas inlet 20 is connected to a servo controller 18, a pressure regulating device 17, and a magnetic pump 16 in sequence via an inlet pipe. A flow meter is also installed in the inlet pipe to acquire flow data.

[0052] Furthermore, the well wall concrete performance testing device also includes a protective door to facilitate operations such as sample replacement and debugging; the protective door is equipped with an observation window to facilitate operators to observe the experimental situation, and the observation window can be made of materials such as high pressure resistant and corrosion resistant tempered glass.

[0053] The above technical solution will be described in detail below through a specific embodiment:

[0054] This specific embodiment includes the following main parts:

[0055] 1. Overall structure of the device (i.e., the device housing)

[0056] The testing device uses a high-strength alloy steel frame to ensure that the overall structure has sufficient strength and rigidity to withstand pressure from all directions and the weight and force of the internal system. The frame is wrapped with stainless steel plates to form a closed structure, namely the device shell. The stainless steel plates are 5-8mm thick, which provides good protection and a certain degree of corrosion resistance, effectively protecting the internal components of the device shell and preventing liquid leakage.

[0057] The device housing is divided into different functional areas, and each chamber is equipped with a sealing and heat insulation structure to prevent mutual interference between the heating, corrosion and pressure systems, and to ensure the independence and stability of experimental conditions.

[0058] 2. Heating system

[0059] Heating element selection and layout: The heater 14 uses a PTC ceramic heating plate 25 as the heating element, which has the advantages of automatic temperature control and safety and reliability. According to the space size of the rear cavity 100 and the heating power requirements, a suitable PTC ceramic heating plate 25 is selected. The PTC ceramic heating plate 25 is fixed by a specially made outer frame to ensure that it is in close contact with the rear side wall of the well wall concrete sample 2, which is conducive to heat conduction and ensures the stability of the PTC ceramic heating plate 25.

[0060] Heat dissipation and insulation design: To ensure the stable operation of the PTC ceramic heating plate 25, aluminum heat sinks 24 with dimensions of 80mm×40mm×15mm are installed on both sides of it, which effectively increases the heat dissipation area and dissipates the heat generated during the heating process in a timely manner.

[0061] Temperature Monitoring and Control: Three temperature sensors 15 are installed on the front and rear surfaces of the well wall concrete sample 2, distributed at different locations, to accurately monitor temperature changes. The temperature sensors 15 are connected to a temperature control device, with a target temperature range of 20-100℃ and a control accuracy of ±1℃. When the temperature is below the set value, the temperature control device increases the power supply to the PTC ceramic heating plate 25; when it is above the set value, the power is reduced to ensure accurate and stable heating temperature. Simultaneously, an over-temperature alarm function is set on the temperature control device. When the temperature exceeds the set safety upper limit (e.g., 100℃), the power supply is immediately cut off and an alarm signal is issued to ensure equipment and experimental safety.

[0062] 3. Corrosion Testing System

[0063] Corrosive medium storage and supply: A corrosion-resistant storage tank with a capacity of 100-150L is set up to store the ion-containing chemical corrosive solution 21. The concentration of the corrosive solution 21 is set based on the measured results of groundwater in the mine and considering the experimental time factor. This invention is designed to be 2-4 times higher than the concentration of corrosive components in groundwater under actual geological conditions, for example, 2.5 times, 3 times, 3.5 times, or 4 times. This higher concentration allows for better test results in a shorter time and achieves better simulation results under experimental or testing conditions. For example, in a survey of groundwater samples from a certain mine, the main corrosive chemical component is sulfate ions, with a concentration of 1800 mg / L. Considering the high-concentration ion acceleration experiment, a 5000 mg / L sulfate ion solution is prepared for testing. In this way, the impact of the actual corrosion degree can be better reflected through testing. Based on Bernoulli's principle, the corrosive solution 21 is transported from the storage tank to the nozzle 12 through a magnetic pump 16 and a pressure regulating device 17. The supply of the corrosive solution 21 can be precisely adjusted according to experimental needs.

[0064] Nozzle 12 Design: Nozzle 12 is made of corrosion-resistant ceramic and its design is determined based on experimental requirements and corrosion uniformity. Nozzle 12 is positioned within the corrosion zone 300 and faces the well wall concrete sample 2, ensuring that the corrosive liquid 21 fully covers the front side of the well wall concrete sample 2. The spray angle of nozzle 12 is adjustable, ranging from 0° to 90°. The spray or shower flow rate is adjusted via servo controller 18 to meet the requirements for corrosion area and intensity under different experimental conditions. Furthermore, nozzle 12 can be either a spray device or a shower device. A spray device continuously sprays, simulating the humid and foggy environment of a coastal mine, placing the well wall concrete in a salt spray corrosion environment; while a shower device sprays chemicals, simulating the water-rich environment underground in a mine, placing the well wall concrete in a corrosive water shower environment.

[0065] Corrosion Product Treatment: A waste liquid collection tank 7 is designed at the bottom of the corrosion zone 300. The waste liquid collection tank 7 is made of polyvinyl chloride (PVC), which has good corrosion resistance. A discharge port 13 is set at the bottom of the waste liquid collection tank 7 to discharge the corrosion waste liquid 6 containing corrosion products to an external waste liquid treatment system. The waste liquid treatment system first treats the acidic waste liquid using a neutralization and precipitation method, and then removes solid impurities through a filtration device, so that the treated corrosion waste liquid 6 meets environmental emission standards before being discharged or recycled.

[0066] 4. Hydraulic pressurization system

[0067] Lateral pressure loading: A set of hydraulic cylinders is installed on each side of the pressurization zone 200 to apply lateral pressure. The rated pressure of the hydraulic cylinder is 150kN, and the stroke is 200-300mm. When the control system (not shown in the figure) sends a start signal to the hydraulic pump 9, the hydraulic pump 9 runs, draws hydraulic oil 11 through the low-pressure oil pipe 8, and after being pressurized by the hydraulic pump 9, it is input to the hydraulic control device 3 through the high-pressure oil pipe 10. At this time, the control system sends a signal to the hydraulic control device 3 (e.g., an electromagnetic reversing valve) to cause the corresponding hydraulic cylinder oil pipe 4 to output high-pressure oil, causing the corresponding hydraulic cylinder to move. Through the extension and retraction of the hydraulic cylinder, the corresponding pressure block 1 moves. When the pressure blocks 1 on both sides are pressed against the left and right sides of the well wall concrete sample 2, uniform pressure is applied to the well wall concrete sample 2 in the left and right directions. At the same time, by installing a pressure sensor between the hydraulic cylinder and the well wall concrete sample 2, the lateral pressure change is monitored, and the pressure control accuracy is ±0.2MPa.

[0068] Vertical pressure loading: Similar to the lateral pressure loading method, a set of hydraulic cylinders is installed on each of the left and right sides within the pressure zone 200 to apply vertical pressure. By controlling the raising and lowering of these vertical hydraulic cylinders, stable vertical pressure is applied to the well wall concrete sample 2. A pressure sensor is installed at the top to monitor the vertical pressure in real time, with a measurement accuracy of ±0.1MPa.

[0069] Hydraulic pressurization system control: The entire hydraulic pressurization system is controlled by one Figure 3 The centralized hydraulic pump station shown provides power and is equipped with hydraulic pump 9 and hydraulic control devices to achieve precise control and stable supply of pressure in all directions. Through the combination of a programmable logic controller (PLC) and a control system (e.g., a computer), operators can easily set parameters such as pressure loading curves, loading speed, and holding time in each direction on the control system, and monitor pressure changes in real time. The control system has an automatic pressure compensation function; when pressure fluctuations occur, it can promptly adjust the output of the hydraulic pump to ensure that the pressure remains stable within the set range.

[0070] 5. Ultrasonic testing system

[0071] A non-metallic ultrasonic testing instrument was selected, with the ultrasonic probe 5 chosen and arranged as follows: a high-frequency (e.g., 50kHz~1MHz), high-sensitivity ultrasonic probe 5 was selected, and multiple ultrasonic probes 5 were embedded on the surface of the compaction block, for example, 16 ultrasonic probes 5 were evenly arranged on the surface of each compaction block. This ensured that the ultrasonic probes 5 were in close contact with the surface of the well wall concrete sample 2, forming an ultrasonic monitoring network, and was able to adapt to temperature changes, pressure deformation, and other conditions during the experiment.

[0072] To achieve simulations of downhole conditions lasting months, years, or even decades within a short period (30-360 days, especially short periods of 30, 40, 50, or 60 days), such as... Figure 6 As shown, in one embodiment of the present invention, 16 50kHz ultrasonic probes 5 are uniformly arranged on the surface of each compaction block, forming a 4×4 rectangular phased array probe. By precisely controlling the emission time and phase of each probe, omnidirectional scanning can be achieved, generating high-resolution images of the concrete structure, thereby more accurately detecting and locating defects. This ensures both measurement accuracy and prevents excessive data volume, reducing problems such as slow evaluation, lengthy processing time, and high requirements on the processing system caused by excessive data processing. Furthermore, to reduce the burden of data processing, the present invention can also use a 3×3 phased array.

[0073] The speed of sound in air is approximately 340 meters per second. Based on the formula, the wavelength of the 50kHz ultrasonic probe used in this invention is approximately 7.6 millimeters. The distance between two adjacent ultrasonic probes is set at 20mm, approximately three times the wavelength. Each ultrasonic probe is 20mm from the edge of the well wall concrete sample. The applicant's main considerations for setting the above ultrasonic frequency and probe spacing are:

[0074] 1. Accuracy Requirements: To avoid missing minute defects, higher resolution is needed, necessitating a smaller probe spacing, approximately 2-3 times the wavelength. An appropriate spacing-to-wavelength ratio contributes to more precise detection of internal concrete defects. When the spacing is within 2-3 times the wavelength, the ultrasonic signal can densely cover the detection area, effectively detecting even minute defects. Because a smaller spacing makes defects more likely to fall within the detection range of a single probe, and multiple probes detecting from different angles can acquire more comprehensive defect information. For example, when detecting tiny voids inside well wall concrete, an appropriate spacing ensures that voids are detected promptly, preventing omissions.

[0075] 2. Avoiding Signal Confusion: When the probe spacing is less than 2-3 times the wavelength, it effectively avoids the confusion between ultrasonic signals emitted and received by adjacent probes. Because ultrasonic signals diffuse when propagating in concrete, if the probe spacing is too large, the signal coverage areas of different probes overlap excessively, making it difficult to distinguish which area the signal originates from, leading to inaccurate detection results. For example, when detecting tiny cracks in well wall concrete, a smaller probe spacing allows the reflected signals received by each probe to be relatively independent, clearly reflecting the situation within their respective detection areas and accurately determining the location and size of the crack.

[0076] 3. Data processing requirements: Too small a probe spacing or too dense a probe spacing can lead to problems such as slow evaluation due to excessive data processing, long processing time, and high requirements for the processing system, thus increasing the burden of data processing.

[0077] In this way, the wavelength and spacing selected by the present invention can fully detect minute defects such as cracks and voids between two ultrasonic probes. Especially when an ultrasonic monitoring network of phased array probes is formed, minute defects such as cracks and voids can be detected within a short experimental testing time. These minute defects such as cracks and voids are the precursors to damage and corrosion of the well wall concrete months, years or even decades later. If ordinary ultrasonic probes are used, or if a phased array probe is not formed, it is difficult to fully and accurately detect the minute changes of the well wall concrete sample, and it is easy to miss minute but fatal defects in the future.

[0078] Ultrasonic signal transmission and reception: A high-frequency ultrasonic pulse signal is generated by an ultrasonic generator and transmitted to each ultrasonic probe 5 via signal lines, causing it to emit ultrasonic waves into the well wall concrete sample 2. As the ultrasonic signal propagates within the well wall concrete sample 2, it undergoes reflection, refraction, and scattering when it encounters internal defects (such as microcracks or voids), interfaces between different media (such as the aggregate-cement paste interface), or areas where material properties have changed due to temperature or pressure variations. The reflected ultrasonic signal is received by the ultrasonic probe 5 and transmitted back to the ultrasonic receiver via signal lines.

[0079] Signal Processing and Analysis: The ultrasonic receiver amplifies and filters the received signal before transmitting it to a data acquisition card. The data acquisition card converts the analog signal into a digital signal and transmits it to the ultrasonic signal analysis device. The ultrasonic signal analysis device runs specially developed ultrasonic data analysis software, which uses algorithms to extract and analyze the characteristic parameters of the ultrasonic signal (such as amplitude, frequency, and propagation time). By comparing the characteristics of the ultrasonic signals acquired at different times, the device can determine in real time the development of defects inside the well wall concrete sample 2, changes in material homogeneity, and the degree of structural damage caused by factors such as temperature, pressure, and corrosion. For example, if the propagation time of the ultrasonic signal suddenly increases, it may indicate the appearance of new cracks or voids inside the well wall concrete sample 2, resulting in a longer sound wave propagation path; if the amplitude decreases, it may be due to a decrease in material density or an increase in defects, leading to increased attenuation of sound wave energy.

[0080] 6. Data Acquisition and Control System

[0081] Data Acquisition System: Equipped with a multi-channel data acquisition unit, it collects data from temperature sensor 15, pressure sensors in various directions, flow meters, and ultrasonic monitoring systems. The data acquisition frequency can be set from 1 to 100 Hz to meet different test data acquisition needs. The acquired data is transferred to a computer via a USB interface for storage and analysis.

[0082] Control System: An industrial control computer is used as the host computer, combined with a programmable logic controller (PLC) to achieve centralized control of the entire wellbore concrete performance testing device. A visual operation interface is developed on the host computer, allowing operators to easily set experimental parameters, such as heating temperature, type and flow rate of corrosive liquid 21, pressure loading curves in various directions, etc., and monitor the changes of each parameter in real time during the experiment. The PLC is responsible for executing the host computer's instructions and controlling the operation of the heating system, corrosion testing system, hydraulic pressurization system, etc., to ensure that the test is carried out in an orderly manner according to the preset program.

[0083] Based on the above, a performance testing database for well wall concrete will be established to store and manage a large amount of test data. Big data analytics will be used to uncover potential relationships between data points, such as the influence of different loading conditions, temperature environments, and corrosive media on the performance of well wall concrete. Machine learning algorithms, such as neural networks and decision trees, will be applied to predict and evaluate the performance of well wall concrete. Through AI, the prediction and evaluation of well wall concrete performance can be achieved more accurately and quickly.

[0084] 7. Safety Protection System

[0085] Overpressure protection: Safety valves and overpressure alarm devices are installed in each pressure branch of the hydraulic pressurization system. When the pressure exceeds the system's set safety threshold, the corresponding safety valve will automatically open to release pressure, and the alarm device will issue an audible and visual alarm signal to remind the operator to handle the situation in time and prevent equipment damage and safety accidents.

[0086] Over-temperature protection: An over-temperature protection controller is set in the heating system. When the temperature sensor 15 detects that the heating temperature exceeds the set maximum temperature (e.g., 100℃), the power supply of the heating system is immediately cut off and the alarm function is activated to ensure that the test is carried out within the safe temperature range.

[0087] Leak detection and protection: Leak detection sensors are installed in the storage tank, the pipeline for conveying corrosive liquid 21, and inside the pressurization area 200 to monitor in real time for leaks of corrosive liquid 21 or hydraulic oil 11. Once a leak is detected, the operation of the relevant equipment is immediately stopped, and corresponding protective measures are taken, such as ventilation and isolation of the leak source, to ensure the personal safety of operators.

[0088] 8. Protective Door and Observation Window: A protective door is installed on the front side of the well wall concrete performance testing device (i.e., on the front side of the corrosion zone 300). The protective door has a double-layer structure, with an inner layer of stainless steel plate and an outer layer of transparent polycarbonate plate, with heat insulation material sandwiched in between. A high-strength door lock is installed on the protective door to ensure its sealing and safety during testing. An observation window is installed on the protective door to facilitate operators' observation of the experimental situation. The observation window is made of high-pressure resistant and corrosion-resistant tempered glass.

[0089] The working process of the wellbore concrete performance testing device described in this specific embodiment is explained below:

[0090] 1. Prepare the appropriate type and concentration of corrosive liquid 21 according to the test requirements, adjust the nozzle 12, turn on the power of the device, and start the control system and data acquisition system. On the computer operation interface of the control system, set parameters such as heating temperature, flow rate of corrosive liquid 21, pressure loading curves in each direction, and loading speed according to the test requirements.

[0091] Open the protective door, place the prepared well wall concrete sample 2 on the lower pressure block 1 in the pressure zone 200, fix temperature sensors 15 on the front and rear surfaces of the well wall concrete sample 2 respectively, and then close the protective door and ensure good sealing.

[0092] 2. Start the hydraulic pressurization system. The hydraulic pump supplies oil to each cylinder according to the set pressure loading curve, applying lateral and vertical pressure to the four sides of the well wall concrete sample 2 (during this process, the lower pressure block 1 first rises to lift the well wall concrete sample 2 to the middle position of the pressurization zone 200, and then all four pressure blocks 1 apply pressure to the well wall concrete sample 2 together). During the test, the data acquisition system collects and stores data such as temperature, pressure, and flow rate of the corrosive liquid 21 in real time.

[0093] 3. Start the heating system. The temperature control device automatically adjusts the power supply of the PTC ceramic heating plate 25 according to the set temperature, so that the temperature of the rear side of the well wall concrete sample 2 rises and stabilizes within the set range.

[0094] 4. Start the corrosion testing system. The magnetic pump 16 delivers the corrosive liquid 21 from the storage tank to the nozzle 12, spraying it onto the front surface of the well wall concrete sample 2 according to the set flow rate and angle, thus beginning the corrosion experiment. A temperature difference is formed between the front and back surfaces of the well wall concrete sample 2. During subsequent testing, the corrosive liquid 21 is treated and replenished in a timely manner.

[0095] 5. During the test, the operator can observe the changes in the concrete sample 2 of the well wall through the observation window, and at the same time monitor the various parameters on the computer operation interface of the control system. If any abnormal situation such as overpressure, overtemperature or leakage occurs, the safety protection system will immediately activate the corresponding protection measures, such as safety valve depressurization, overtemperature alarm and power cut-off, leakage detection alarm and stop the operation of related equipment, to ensure the safe conduct of the experiment.

[0096] 6. When the test reaches the set time or predetermined conditions, stop the hydraulic pressurization system, corrosion testing system and heating system in sequence, open the protective door, take out the well wall concrete sample 2, and conduct subsequent performance tests and analyses on the well wall concrete sample 2, such as compressive strength test, microstructure analysis, etc., to evaluate the performance changes of the well wall concrete sample 2 under multi-directional pressure, front and back temperature difference and corrosive environment.

[0097] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0098] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for testing the performance of well wall concrete, characterized in that, The device includes a hollow housing, which is divided into a rear cavity (100) and a front cavity, and the front cavity is divided from rear to front into a pressurization zone (200) and a corrosion zone (300); The pressurization zone (200) accommodates a cubic well wall concrete sample (2), and multiple movable pressure blocks (1) are provided in the pressurization zone (200). The side of the pressure block (1) facing the center of the pressurization zone (200) is a plane. A heater (14) is provided in the rear cavity (100), and the front side of the heater (14) can fit against the rear side of the well wall concrete sample (2); The corrosion zone (300) is equipped with a nozzle (12), and the front side of the well wall concrete sample (2) is located within the spray range of the nozzle (12); A heat insulation plate (26) is provided between the rear cavity (100) and the front cavity, and the heat insulation plate (26) is provided with an opening for heating the well wall concrete sample (2); The heater (14) includes a square outer frame and a strip-shaped PTC ceramic heating plate (25) connected inside the outer frame, and heat sinks (24) are connected to the side of the PTC ceramic heating plate (25). The well wall concrete performance testing device also includes multiple temperature sensors (15) and a temperature control device. The temperature sensors (15) are respectively connected to the front and rear sides of the well wall concrete sample (2), and the temperature control device is electrically connected to the PTC ceramic heating plate (25).

2. The wellbore concrete performance testing device as described in claim 1, characterized in that, Four pressure blocks (1) are evenly distributed in the four directions of the pressurization zone (200), namely the upper, lower, left and right. Each pressure block (1) is connected to the hydraulic pump (9) through a corresponding hydraulic cylinder. The hydraulic cylinder corresponding to the pressure block (1) on the left is arranged horizontally, the hydraulic cylinder corresponding to the pressure block (1) on the right is arranged horizontally, the hydraulic cylinder corresponding to the pressure block (1) on the upper is arranged vertically, and the hydraulic cylinder corresponding to the pressure block (1) on the lower is arranged vertically.

3. The wellbore concrete performance testing device as described in claim 2, characterized in that, A pressure sensor is also provided between the pressure block (1) and the corresponding hydraulic cylinder. The pressure sensor is a strain gauge force sensor.

4. The wellbore concrete performance testing device as described in claim 1, characterized in that, It also includes an ultrasonic transmitter, an ultrasonic receiver, and an ultrasonic signal analysis device; an ultrasonic probe (5) is connected to the side of the pressure block (1) facing the center of the pressure zone (200), the ultrasonic probe (5) is connected to the ultrasonic transmitter and the ultrasonic receiver respectively, and the ultrasonic signal analysis device is electrically connected to the ultrasonic receiver.

5. The wellbore concrete performance testing device as described in claim 4, characterized in that, A groove is provided on the side of the pressure block (1) facing the center of the pressure area (200), the volume of the groove is larger than the volume of the ultrasonic probe (5), and the ultrasonic probe (5) is disposed in the groove.

6. The wellbore concrete performance testing device as described in claim 1, characterized in that, A waste liquid collection tank (7) is also connected to the bottom of the device housing.

7. The wellbore concrete performance testing device as described in claim 1, characterized in that, The nozzle (12) includes a corrosive liquid inlet (19) and a high-pressure gas inlet (20) that are interconnected. The corrosive liquid inlet (19) is connected to a storage tank containing corrosive liquid (21) through an inlet pipe. The high-pressure gas inlet (20) is connected to a servo controller (18), a pressure regulating device (17) and a magnetic pump (16) in sequence through an inlet pipe. A flow meter is also provided in the inlet pipe.

8. The wellbore concrete performance testing device as described in claim 4, characterized in that, Sixteen ultrasonic probes (5) are evenly arranged on the surface of each pressing block to form a 4×4 phased array; the frequency of the ultrasonic probes (5) is 50kHz.

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