Water tank experiment sedimentary profile obtaining device and method based on freezing profile technology

Abstract

The invention discloses a device and a method for acquiring a water tank experiment sedimentary profile based on a frozen profile technology, and belongs to the technical field of sedimentology and experimental simulation, and the device and the method are characterized in that stable freezing extraction of the sedimentary profile in a water tank is realized through a wedge-shaped freezing device. The device is internally provided with a liquid nitrogen channel and is provided with an external control interface, and a section freezing state can be kept by injecting liquid nitrogen in batches, so that a complete sedimentary section sample is obtained. Meanwhile, the invention provides a corresponding profile acquisition method, and emphasizes speed control, friction force control, liquid nitrogen injection rhythm and pull-out stability of the insertion device, so as to ensure that an undisturbed frozen profile sample is acquired. According to the method, disturbance to a sedimentary body structure can be remarkably reduced, and the precision and analysis efficiency of profile data are effectively improved, so that reliable technical support is provided for source-sink system and sedimentary geomorphology research.

Description

Technical Field

[0001] This invention relates to the fields of sedimentology and experimental simulation technology, and more specifically to a device and method for obtaining sedimentary profiles in a water tank experiment based on freezing profile technology. Background Technology

[0002] Physical simulation experiments using sedimentary flumes recreate the depositional processes of river, lake, or marine sediments by simulating the hydrodynamic conditions and sediment supply mechanisms in natural sedimentary environments. This is a crucial method for studying the structure and genesis of sedimentary bodies. Obtaining sedimentary profile information from flume experiments is essential for analyzing sedimentary dynamics, provenance contributions, and stratigraphic structure. However, currently used sedimentary profile analysis methods, such as profile cutting, laser scanning, and computed tomography (CT) techniques, all have significant limitations in practical applications and cannot fully meet the demands for high-precision, low-disturbance profile data in the study of complex sedimentary systems.

[0003] Profiling techniques typically require manually cutting the experimental sediment body after the experiment to obtain a profile and photographing it to record data. This method is complex, demands a high level of experience from the experimenters, and the cutting process itself causes significant disturbance to the sediment body. Especially for low-density powdery materials or fine-grained sediments, cutting can easily cause local collapse or damage to the overall structure. Furthermore, when the profile length is large, it is difficult to capture both the panoramic view and local details in a single photograph; if multiple images are stitched together, variations in lighting and angle can easily cause stitching errors, reducing the accuracy and reliability of the sedimentary data.

[0004] Laser scanning technology can provide intuitive and continuous sedimentary profile structures through high-resolution 3D modeling. However, its application in 3D sedimentary flume experiments typically requires pre-draining the water from the flume. This drainage process can trigger the collapse or sliding of fine-grained sediments and low-density materials, causing secondary disturbance to the sedimentary structure and preventing the scanning results from accurately reflecting the original state of the sedimentary profile. Although transparent glass sidewalls can be used to directly observe sedimentary layers in 2D narrow flume experiments, thus partially avoiding disturbance, this method is only suitable for small-scale experimental systems with simple sedimentary structures and cannot meet the needs of complex 3D sedimentary experiments.

[0005] Computed tomography (CT) technology has seen some application in experimental sedimentology research in recent years. CT scans offer the advantage of sequential tomographic imaging, theoretically allowing the acquisition of detailed internal structures of sedimentary bodies without damaging the sample, and providing data similar to multi-layered profiles. However, current CT technologies face constraints in practical applications due to the trade-off between volume and resolution: micron-level CT, while possessing ultra-high resolution of 1–10 μm, is limited by the size of the scanning chamber and is only suitable for smaller experimental samples; industrial-grade CT can scan larger models, but its resolution is typically only tens to hundreds of micrometers, making it difficult to effectively resolve fine sedimentary structures. Furthermore, CT imaging relies on density differences between sample materials for identification and reconstruction; the physical properties of the experimental materials (such as density) require additional matching or correction, otherwise, the imaging results are prone to distortion. These factors further limit the widespread application of CT technology in experimental sedimentology.

[0006] In summary, existing profile cutting, laser scanning, and CT scanning techniques struggle to simultaneously ensure the structural integrity of sedimentary profiles while maintaining high precision and resolution, especially in the study of complex three-dimensional sedimentary systems. Therefore, achieving high-precision, high-resolution sedimentary profile acquisition with minimal disturbance has become a pressing technical challenge in current experimental research in sedimentology and stratigraphy. Summary of the Invention

[0007] In view of this, the present invention provides a device and method for obtaining sedimentation profiles in a water tank experiment based on freezing profile technology, aiming to efficiently obtain the complete structure of the sedimentation profile.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: On one hand, the present invention provides a device for obtaining sedimentation profiles in a water tank experiment based on cryogenic profiling technology, comprising: a cryogenic device body, a monitoring device, cryogenic pipes, a liquid nitrogen tank, and a control system; The refrigeration device is wedge-shaped and is used to conduct the cold energy of the refrigeration pipes; The monitoring device is installed on the refrigeration pipe to monitor the environmental parameters inside the refrigeration pipe and transmit them to the control system. The refrigeration pipe is connected to the liquid nitrogen tank and is used to guide the flow of liquid nitrogen; The liquid nitrogen tank is injected with liquid nitrogen according to the control signal from the control system; The control system is used to control the injection of liquid nitrogen into the liquid nitrogen tank and the venting of the refrigeration pipes according to the environmental parameters.

[0009] Preferably, the refrigeration device includes a vertical freezing surface, an inclined insertion surface, and a sealing cover. The vertical freezing surface is used to directly contact the deposits and conduct the cold energy of the refrigeration pipes. The inclined insertion surface is used for guidance and drag reduction. The sealing cover is disposed above the vertical freezing surface and the inclined insertion surface and is used to seal the liquid nitrogen refrigeration chamber.

[0010] Preferably, the refrigeration pipeline includes an external liquid nitrogen pipeline disposed above the refrigeration device and a serpentine passage disposed inside the refrigeration pipeline. The external liquid nitrogen pipeline is provided with a solenoid valve and an interface. The solenoid valve is used to control the injection of liquid nitrogen, and the interface is used to connect to the liquid nitrogen tank. One end of the serpentine passage is connected to the external liquid nitrogen pipeline, and the other end is connected to an exhaust port. The exhaust port is disposed on the side of the refrigeration device.

[0011] Preferably, the monitoring device includes: A pressure sensor is installed on the external liquid nitrogen pipeline to monitor the pressure signal inside the serpentine passage; A temperature sensor is installed on the serpentine path to monitor the temperature inside the serpentine path.

[0012] Preferably, the freezing device is provided with handles on its sides.

[0013] Preferably, the freezing device is provided with a support column.

[0014] On the other hand, the present invention provides a method for obtaining sediment profiles in a water tank test based on freezing profiling technology, comprising: The wedge-shaped freezing device is inserted vertically and slowly into the sediment in the water tank at a uniform speed until it covers the full thickness of the target profile. After the wedge-shaped freezing device is in place, a cooling medium is intermittently injected into the internal cooling channel to cool the vertical freezing surface of the wedge-shaped freezing device, thereby freezing and solidifying the deposition profile layer by layer that is in close contact with the vertical freezing surface to form a frozen deposition profile layer. After the deposition profile is frozen, the wedge-shaped freezing device is slowly and uniformly pulled out of the sediment, so that the frozen deposition profile layer attached to the vertical freezing surface is taken out as a whole, and a complete deposition profile sample is obtained. The sedimentary profile samples were photographed to obtain profile images; The obtained cross-sectional images are digitized using image processing software.

[0015] As can be seen from the above technical solution, compared with the prior art, this invention discloses a system and method for obtaining sediment profiles in a water tank test based on freezing profile technology. By using an inclined insertion surface forming an angle of approximately 30° with the vertical freezing surface for guidance and drag reduction, the wedge can be smoothly inserted into the sediment with minimal disturbance. The serpentine pathway significantly extends the flow path of liquid nitrogen within the device, increasing the effective heat exchange area and allowing more cooling energy to be transferred to the vertical freezing surface compared to a straight channel. The curved pathway creates turbulence in the liquid nitrogen flow, breaking boundary layer stagnation and improving the contact efficiency between the cooling energy and the inner wall of the pathway, ensuring that the cooling energy is fully and uniformly conducted to the entire freezing surface. Under the monitoring and feedback control of temperature sensors, liquid nitrogen can be injected intermittently, achieving gradual cooling rather than instantaneous supercooling, thus freezing and solidifying the sediment profile closely adhering to the vertical freezing surface layer by layer, avoiding the cracking of the sediment structure caused by a single rapid freezing. The extension of the serpentine pathway also increases the liquid nitrogen residence time, making the vaporization process smoother, maintaining the pressure balance within the system, and reducing the risk of sudden pressure rises. This invention can significantly improve the accuracy and efficiency of sedimentary profile information acquisition, overcome the shortcomings of traditional methods such as large disturbances and low accuracy, and realize fine quantitative analysis of the geometric structure and dynamic evolution process of complex sedimentary systems. It has the beneficial effects of undisturbed acquisition of sedimentary structure and high data accuracy. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the wedge-shaped freezing device; Figure 2 This is a diagram showing the internal liquid nitrogen pathway and sensor layout of the device. Figure 3 To construct a time series diagram of relative sea level under subsidence (30h); Figure 4 This is a photograph of the sediment profile after cryo-extraction.

[0018] The components include: 1. Sealing cover; 2. Freezing vertical surface; 3. Inclined insertion surface; 4. Liquid nitrogen inlet interface; 5. Solenoid valve; 6. Pressure sensor; 7. Exhaust port; 8. External liquid nitrogen pipeline; 9. Support column; 10. Side handle; 11. Temperature sensor; 12. Serpentine path; and 13. Fixture. Detailed Implementation

[0019] 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.

[0020] This invention discloses one aspect: a device for obtaining sediment profiles in a water tank experiment based on cryoprofiling technology, such as... Figure 1 As shown, it includes: the main body of the refrigeration unit, monitoring device, refrigeration pipes, liquid nitrogen tank, and control system; The refrigeration device is wedge-shaped and is used to conduct the cold energy of the refrigeration pipes; The monitoring device is installed on the refrigeration pipe to monitor the environmental parameters inside the refrigeration pipe and transmit them to the control system. The refrigeration pipe is connected to the liquid nitrogen tank to guide the flow of liquid nitrogen; The liquid nitrogen tank is injected with liquid nitrogen according to the control signal from the control system; The control system is used to control the injection of liquid nitrogen into the liquid nitrogen tank and the venting of the refrigeration pipes according to the environmental parameters.

[0021] Specifically, the freezing device includes a vertical freezing surface 2, an inclined insertion surface 3, and a sealing cover plate 1. The vertical freezing surface 2 is used to directly contact the sediment and conduct the cold energy of the freezing pipe. The inclined insertion surface 3 forms an angle of approximately 30° with the vertical freezing surface 2, serving as a guide and reducing drag, allowing the wedge to gradually expand the space when inserted into the sediment, entering the sediment with less resistance and a smooth posture, thereby minimizing disturbance to the surrounding sedimentary structure. The sealing cover plate 1 is located above the vertical freezing surface 2 and the inclined insertion surface 3, and is used to seal the liquid nitrogen freezing chamber.

[0022] Furthermore, such as Figure 2 As shown, the refrigeration pipeline includes an external liquid nitrogen pipeline 8 located above the refrigeration unit and a serpentine passage 12 located inside the refrigeration pipeline. The external liquid nitrogen pipeline 8 is equipped with a solenoid valve 5 and an interface 4. The solenoid valve 5 is used to control the injection of liquid nitrogen, and the interface 4 is used to connect to the liquid nitrogen tank. One end of the serpentine passage 12 is connected to the external liquid nitrogen pipeline 8, and the other end is connected to the exhaust port 7. The exhaust port 7 is located on the side of the refrigeration unit. The exhaust port 7 serves as a safety pressure relief structure. When the internal vaporization pressure exceeds the upper limit, it can automatically release excess nitrogen gas to prevent the pressure inside the cavity from becoming too high and causing danger.

[0023] Furthermore, the serpentine passageway is fixed to the vertical surface 2 of the freezer via a retainer.

[0024] In this embodiment, the serpentine passage 12 has a diameter of approximately 4 mm, a coil pitch of approximately 10 mm, and six loops, with a total length of approximately 1 m. This extends the liquid nitrogen flow path, increases the heat exchange area, and achieves uniform cooling of the entire freezing surface. A temperature sensor 11 is positioned in the middle of the serpentine passage 12 to monitor the liquid nitrogen reflux temperature, representing the overall cooling status of the wedge. A pressure sensor 6 is installed at the top of the wedge to monitor real-time pressure changes within the wedge. An exhaust port 7 is provided on the side wall of the wedge body. When liquid nitrogen vaporizes within the serpentine passage 12, causing the internal pressure to exceed a predetermined upper limit (e.g., 0.20 MPa(g)), the exhaust port 7 automatically opens to release pressure, ensuring the safety of the internal pressure within the cavity.

[0025] The internal serpentine liquid nitrogen passage 12 of this invention is one of the core components of the wedge-shaped freezing device. This serpentine passage 12 is installed inside the wedge-shaped body to guide the flow of liquid nitrogen and efficiently conduct cooling. The serpentine design significantly extends the flow path of liquid nitrogen within the device, increasing the effective heat exchange area and allowing more cooling to be transferred to the vertical freezing surface compared to a straight channel. The curved passage creates turbulence in the liquid nitrogen flow, breaking boundary layer stagnation and improving the contact efficiency between the cooling capacity and the inner wall of the passage, ensuring that cooling energy is fully and evenly conducted to the entire freezing surface. This design ensures uniform temperature distribution, avoiding the uneven distribution that can occur with straight pipe passages, where the front end is overcooled while the end temperature rises. Under the monitoring and feedback control of the temperature sensor 11, liquid nitrogen can be injected intermittently, achieving gradual cooling rather than instantaneous supercooling, thus freezing and solidifying the deposition profile adjacent to the vertical freezing surface layer by layer, avoiding cracking of the deposition structure caused by a single rapid freezing. The extension of the serpentine passage 12 also increases the liquid nitrogen residence time, making the vaporization process smoother, maintaining the internal pressure balance of the system, and reducing the risk of sudden pressure rises. In summary, by combining the batch injection rhythm control of solenoid valve 5, this invention forms the core technical basis for low-disturbance freezing extraction of sedimentation profiles.

[0026] Furthermore, the monitoring device includes: Pressure sensor 6 is installed on the external liquid nitrogen pipeline 8 to monitor the pressure signal inside the serpentine passage 12; Temperature sensor 11 is disposed on the serpentine passage 12 for monitoring the temperature inside the serpentine passage 12.

[0027] In another embodiment, the freezing device is provided with handles 10 on its sides to facilitate manual gripping of the operating device when obtaining cross-sections; In another embodiment, the freezing device is provided with a support column 9, located on one side of the inclined insertion surface 3, for supporting and stabilizing the wedge during insertion and liquid nitrogen injection. To reduce frictional resistance and minimize disturbance damage during the insertion of the deposit, the outer surfaces of the vertical freezing surface and the inclined insertion surface are coated with an anti-friction coating, such as a thin film formed by water or glycerin, which can effectively reduce friction during the insertion process.

[0028] Furthermore, the liquid nitrogen inlet port 4, solenoid valve 5, pressure sensor 6, and temperature sensor 11 of this device are all installed on the sealing cover plate 1 on the top of the wedge-shaped body, and are connected in series to an external liquid nitrogen tank through an external liquid nitrogen pipeline 8. During operation, liquid nitrogen is injected into the device through the inlet port. The solenoid valve 5, as a control component, automatically opens or closes the liquid nitrogen injection based on the feedback signal from the temperature sensor 11, realizing batch injection and preventing over-cooling. The pressure sensor 6 monitors the pressure changes inside the wedge caused by the vaporization of liquid nitrogen in real time. When the pressure exceeds the safety threshold, it will automatically issue a warning signal or shut down the liquid nitrogen inlet in conjunction with the system, thereby ensuring system safety. The temperature sensor 11 is located in the middle of the internal serpentine passage, monitors the return temperature of liquid nitrogen at the end of the serpentine passage 8 in real time, and feeds the signal back to the solenoid valve control system to ensure that the temperature control can reflect the overall heat exchange status.

[0029] On the other hand, the present invention provides a method for obtaining sediment profiles in a water tank test based on freezing profiling technology, comprising: Select the location of the profile to be extracted, maintain a stable water level in the tank (to avoid sudden drops in water level that could cause sediment collapse), and align the vertical freezing face of the wedge-shaped freezing device with the surface of the profile area. Then, slowly insert the wedge along the vertical direction of the sediment layer at a low and uniform speed, allowing it to gradually penetrate deeper into the sediment. In actual operation, the insertion speed is approximately 0.6 mm / s, and the wedge's attitude and thrust are steadily controlled using the side handle to ensure that the wedge remains parallel to the tank sidewall and does not tilt or twist. The wedge angle structure of the wedge's inclined surface helps it to be smoothly introduced into the sediment, preventing forceful insertion that could disturb the water or damage the sediment layer structure. Support the wedge using a support column, allowing for real-time monitoring of changes in insertion force and depth. Once the wedge-shaped freezing device has been inserted to the predetermined depth (covering the full thickness of the target sediment profile), stop insertion and fix the wedge position.

[0030] Liquid nitrogen injection and freezing: After the wedge is in place, the liquid nitrogen freezing process is initiated through an external control interface. The control system slowly opens the solenoid valve at the top of the wedge, injecting liquid nitrogen in batches from the inlet into the serpentine passage inside the wedge according to a set rhythm. Specifically, a valve cycle of 2 seconds open and 5 seconds close is used during the pre-cooling stage, a cycle of 3 seconds open and 6 seconds close is used during the main freezing stage, and the valve is briefly opened for 1–2 seconds and closed for 8–10 seconds during the subsequent heat preservation stage to maintain the temperature. The liquid nitrogen flows uniformly within the serpentine passage, absorbing heat and gradually cooling the vertical freezing surface of the wedge, freezing and solidifying the deposition profile adjacent to this surface layer by layer from the surface inward. Temperature sensors monitor the rate of temperature drop inside the wedge in real time, and the control system intermittently opens and closes the solenoid valve accordingly to ensure that the cooling process is gradual and controllable, avoiding excessively thick frozen layers due to instantaneous overcooling (the frozen profile thickness formed by this device is approximately 6 mm, which can be adjusted within the range of 5–8 mm as needed). After each small batch of liquid nitrogen is injected, a short pause is made to allow the temperature gradient on the freezing surface to gradually decrease before the next injection. This "injection-pause" cycle is repeated multiple times until the entire target profile area is completely frozen. During this process, pressure sensors continuously monitor the internal pressure of the wedge, maintaining it within a safe range of 0.05–0.12 MPa(g). When liquid nitrogen vaporizes and causes a pressure increase, excess gas is promptly released through the vent to prevent the internal pressure from exceeding the upper limit of 0.15 MPa(g). If it unexpectedly reaches the high limit of 0.20 MPa(g), automatic pressure relief is implemented. Through this slow, batch injection and temperature equalization control, stable freezing of the deposition profile area can be achieved.

[0031] Cryo-Profile Extraction: After confirming that the sedimentary profile is completely frozen, slowly and steadily pull out the wedge-shaped cryogenic device. Maintain a uniform pulling speed (approximately 0.4 mm / s) and keep the wedge's posture unchanged during extraction. Utilize the wedge's inclined surface and anti-friction coating to reduce extraction resistance and prevent shaking that could cause the frozen layer to break. As the wedge gradually withdraws, the sedimentary profile sample, originally pressed against the vertical cryogenic surface, becomes firmly attached to the cryogenic surface of the wedge due to freezing and is carried out of the water tank along with the wedge. Quickly place the extracted frozen sedimentary profile sample flat on a pre-prepared cryogenic support plate (to prevent sample melting and deformation) and immediately cover the surrounding area with insulating material, exposing only the side of the profile surface to be imaged. Through these steps, a frozen sedimentary profile sample with a thickness of approximately 6 mm can be obtained. This sample fully reveals the internal layered structure of the sedimentary body without disturbance or damage. Compared to traditional profile cutting or laser scanning methods, this method significantly reduces disturbance to the sedimentary body when acquiring sedimentary profiles, making it particularly suitable for high-precision profile acquisition of low-density powder materials and fine-grained sediments.

[0032] After the sedimentary profile is extracted, it needs to be digitally processed and quantitatively analyzed. Specifically, the digital processing method mainly includes the following steps: (1) Image Acquisition and Preprocessing: High-resolution cameras are used to photograph the vertical sections of the frozen sedimentary profile to obtain clear, distortion-free, and accurate cross-sectional photographs that reflect the sedimentary layer conditions. During shooting, ensure uniform illumination of the profile surface, avoiding direct glare and shadows to guarantee image quality. Select an appropriate lens focal length based on the profile size, and capture the entire profile in one shot. If the profile is too long to be imaged in one shot, it can be photographed in segments and then stitched together, ensuring the camera's optical axis is perpendicular to the profile plane to reduce perspective distortion. After obtaining the original photographs, import them into a computer for standardization processing, such as adjusting brightness / contrast to eliminate the effects of uneven illumination.

[0033] (2) Image Matrixing: The obtained profile images are digitized using image processing software (such as ImageJ). First, the color photographs are converted into grayscale images to facilitate subsequent analysis of grayscale differences between different material layers. Then, based on the brightness differences of each sediment material layer in the grayscale image, an appropriate threshold range is set for layer extraction: the image is divided into several regions through image thresholding, with each region corresponding to a different sediment source. The threshold selection must ensure that the contours of each sediment layer are complete and clear, avoiding over-segmentation or under-segmentation. Next, the binary image (black and white image) obtained from the thresholding process is subjected to noise reduction and smoothing to eliminate shooting noise and jagged edges, making the layer boundaries more accurate. In the final binary image matrix, different grayscale regions represent different sediment source sediment layers, which can serve as the basic data for subsequent quantitative analysis. Specific Implementation Example 1: In this embodiment, the aforementioned wedge-shaped freezing device and method were applied to extract a sediment profile in a typical water tank sedimentation experiment to verify the device's performance and the integrity of the extracted profile. A fine-grained sediment material was used to fill the water tank, forming a layered sedimentary body approximately 10 cm thick. After the experiment, the water level in the tank was kept constant, and the wedge-shaped freezing device was used to extract the sediment profile according to the "Specific Implementation Scheme". During operation, the wedge was slowly inserted vertically into the sedimentary body to the bottom of the tank at an insertion speed of approximately 0.6 mm / s. After the wedge was inserted, the liquid nitrogen freezing process was initiated, injecting liquid nitrogen in batches according to a predetermined rhythm while monitoring the temperature and pressure in real time. In this embodiment, the system controlled the wedge temperature within a range of approximately –100°C (±10°C): when the temperature was above –90°C, the solenoid valve opened to inject liquid nitrogen; when the temperature was below –110°C, the injection was paused, maintaining temperature stability through hysteresis control. During the liquid nitrogen freezing process, the internal pressure of the wedge remained essentially constant at 0.06–0.10 MPa(g), within the set safe range of 0.05–0.12 MPa(g). Based on the time-varying curves of the wedge temperature and internal pressure during the freezing process, it can be seen that the temperature rapidly decreased to near -100°C upon initial liquid nitrogen injection, and then fluctuated slightly around the target temperature. The corresponding pressure curve showed slight fluctuations synchronized with the liquid nitrogen injection cycle, but remained consistently below 0.12 MPa(g), far from reaching the high-pressure upper limit of 0.15 MPa(g) and the automatic pressure relief threshold of 0.20 MPa(g), indicating that the entire freezing process was controlled, stable, and safe.

[0035] After the wedge was maintained at approximately -100°C for a period of time, it was confirmed that the sedimentary profile sample adhering to the wedge surface was completely frozen (freezing thickness approximately 6 mm). At this point, liquid nitrogen injection was stopped, and the wedge was then slowly and vertically pulled out at a uniform speed of approximately 0.4 mm / s. Thanks to sufficient freezing intensity and a smooth extraction operation, the sedimentary profile sample adhered firmly to the vertical frozen surface of the wedge and was completely extracted. The frozen profile sample was removed and placed horizontally, revealing that the original sedimentary bedding remained clearly discernible, without any collapse, displacement, or other disturbances. To further evaluate the impact of extraction speed on the integrity of the sedimentary profile, comparative experiments were conducted under different extraction speed conditions in this embodiment. The relationship curve between the wedge extraction speed and the degree of disturbance in the resulting profile shows that when the extraction speed is low (e.g., 0.4 mm / s and below), the layered structure of the sedimentary profile is almost unaffected; however, as the extraction speed increases, the degree of disturbance to the profile bedding increases significantly. When the extraction speed was increased to 1.0 mm / s, peeling and disturbance were observed in some thin layers, with a significant increase in disturbance. Therefore, to ensure the integrity of the profile sample, the extraction operation should be as slow and smooth as possible. This embodiment successfully extracted undisturbed sedimentary profile samples and verified the effects of temperature, pressure control schemes, and extraction speed on profile integrity, laying the foundation for obtaining sedimentary profiles under complex conditions. Specific Implementation Example 2: This embodiment focuses on a sedimentation experiment with multiple sediment sources and relative sea-level changes. The method of this invention is applied to obtain sedimentary profiles and perform quantitative image analysis. The experiment was conducted continuously in a water tank for 30 hours, with one layer formed per hour. A water level control system simulated the combined process of tectonic subsidence and periodic sea-level fluctuations: the sea-level change period was 3 hours with an amplitude of ±6 mm, while a vertical tectonic subsidence rate of 0.08 mm·h was applied. -1 . Figure 3 The figure shows the relative sea level change over time as set in the experiment. Regarding sediment supply, this embodiment used three source materials with different particle properties and colors (PVC plastic powder, walnut shell sand, and activated carbon particles), representing source A, source B, and source C, respectively. These three sources are grayish-white, brownish-yellow, and black in color, making them easy to distinguish in the cross-sectional images. During the experiment, the proportion of sand supplied by the three sources varied with time steps to simulate the alternating changes in the supply intensity of different sources (Table 1 shows the supply proportions of sources A, B, and C for each sedimentary layer from time 1 to 10 hours). Source B was dominant for most of the time periods, while the supply proportions of sources A and C increased in stages, thus forming a sedimentary sequence with alternating characteristics.

[0037] Table 1. Data on the proportions of the three sediment sources in each sedimentary layer from time 1 to 10.

[0038] After the experiment, the water level in the tank was kept constant, and the wedge-shaped freezing device was inserted into the designated position of the sediment body according to the method in Example 1 to complete the profile freezing extraction. Since the sediment in this experiment contained materials of various colors, the frozen profile clearly showed a layered structure of different material sources on the wedge body (white was PVC powder, brownish-yellow was walnut shell sand, and black was activated carbon). Figure 4 The extracted sedimentary profile photographs clearly show that each sedimentary layer and its internal details are completely preserved. This frozen profile sample shows no mud or sand slippage or mixing, and its lateral and longitudinal structures are continuous and clear, proving that wedge freezing technology can also obtain undisturbed profile samples in multi-source sedimentary systems, providing a reliable foundation for subsequent digital processing and analysis.

[0039] Subsequently, following the digital method provided by this invention, the extracted multi-source sediment profile was image acquired and processed for analysis. First, a high-resolution camera was used to vertically photograph the frozen profile, obtaining a color image encompassing the entire profile. In this image, the color contrast of the sediment layers corresponding to different source materials was significant (distinctly defined gray-white, brownish-yellow, and black). After conversion to grayscale, each source layer displayed varying shades of gray, making it highly suitable as a basis for threshold segmentation. Next, the profile image was imported into ImageJ software for grayscale conversion and threshold segmentation: an appropriate threshold was selected based on the grayscale histogram in the image, dividing the image into three main regions corresponding to the deposition of sources A, B, and C, respectively. After repeated threshold adjustments and binarization, denoising, and smoothing, a clear binary image of the profile layers was finally obtained. The pixel area of ​​each source region was calculated using image analysis functions and compared with the total pixels of the entire profile, thereby quantifying the relative area ratio of the three sources in each sediment layer. This area ratio can be used to approximately represent the volume or mass contribution ratio of the three sources in each layer. Table 1 lists the supply proportions of sources A, B, and C in the first 10 layers (times 1–10) of the experiment, quantitatively demonstrating the changing trend of source combinations over time. It can be seen that in the early layers (times 1–3), source B had a relatively high proportion, while sources A and C each accounted for a certain minor share; in the middle layers (times 4–8), source A rose to become the main source, while source B slightly decreased, and source C maintained a moderate contribution; in the later layers (times 9–10), source B increased again and became dominant. This change in proportion reflects the phased alternation of source supply.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for obtaining sedimentary profiles in a water tank experiment based on cryo-profiling technology, characterized in that, include: The main body of the refrigeration unit, monitoring devices, refrigeration pipes, liquid nitrogen tank, and control system; The refrigeration device is wedge-shaped and is used to conduct the cold energy of the refrigeration pipes; The monitoring device is installed on the refrigeration pipe to monitor the environmental parameters inside the refrigeration pipe and transmit them to the control system. The refrigeration pipe is connected to the liquid nitrogen tank and is used to guide the flow of liquid nitrogen; The liquid nitrogen tank is injected with liquid nitrogen according to the control signal from the control system; The control system is used to control the injection of liquid nitrogen into the liquid nitrogen tank and the venting of the refrigeration pipes according to the environmental parameters.

2. The apparatus for obtaining sedimentation profiles in a water tank experiment based on cryo-profiling technology according to claim 1, characterized in that, The refrigeration device includes a vertical freezing surface, an inclined insertion surface, and a sealing cover. The vertical freezing surface is used to directly contact the deposits and conduct the cold energy of the refrigeration pipes. The inclined insertion surface is used for guidance and drag reduction. The sealing cover is disposed above the vertical freezing surface and the inclined insertion surface and is used to seal the liquid nitrogen refrigeration chamber.

3. The apparatus for obtaining sedimentation profiles in a water tank experiment based on cryo-profiling technology according to claim 1, characterized in that, The refrigeration pipeline includes an external liquid nitrogen pipeline located above the refrigeration unit and a serpentine passage located inside the refrigeration pipeline. The external liquid nitrogen pipeline is equipped with a solenoid valve and an interface. The solenoid valve is used to control the injection of liquid nitrogen, and the interface is used to connect to the liquid nitrogen tank. One end of the serpentine passage is connected to the external liquid nitrogen pipeline, and the other end is connected to an exhaust port, which is located on the side of the refrigeration unit.

4. The apparatus for obtaining sedimentation profiles in a water tank experiment based on cryo-profiling technology according to claim 3, characterized in that, The monitoring device includes: A pressure sensor is installed on the external liquid nitrogen pipeline to monitor the pressure signal inside the serpentine passage; A temperature sensor is installed on the serpentine path to monitor the temperature inside the serpentine path.

5. The apparatus for obtaining sedimentation profiles in a water tank experiment based on cryo-profiling technology according to claim 1, characterized in that, The freezing device is equipped with handles on its sides.

6. The apparatus for obtaining sedimentation profiles in a water tank experiment based on cryo-profiling technology according to claim 2, characterized in that, The refrigeration device is equipped with support columns.

7. A method for obtaining sedimentary profiles in a water tank test based on cryo-profiling technology, characterized in that, include: The wedge-shaped freezing device is inserted vertically and slowly into the sediment in the water tank at a uniform speed until it covers the full thickness of the target profile. After the wedge-shaped freezing device is in place, a cooling medium is intermittently injected into the internal cooling channel to cool the vertical freezing surface of the wedge-shaped freezing device, thereby freezing and solidifying the deposition profile layer by layer that is in close contact with the vertical freezing surface to form a frozen deposition profile layer. After the deposition profile is frozen, the wedge-shaped freezing device is slowly and uniformly pulled out of the sediment, so that the frozen deposition profile layer attached to the vertical freezing surface is taken out as a whole, and a complete deposition profile sample is obtained. The sedimentary profile samples were photographed to obtain profile images; The obtained cross-sectional images are digitized using image processing software.

Images