Method for measuring contact degree and contact stress distribution of rock sample by using pressure sensing paper

Abstract

The invention relates to the technical field of rock mechanics tests, in particular to a method for measuring rock sample contact degree and contact stress distribution by using pressure sensing paper, which comprises the following steps: S1, arranging a plurality of layers of pressure-sensitive films between contact surfaces of two to-be-measured rock samples, and eliminating bubbles on the surfaces of the plurality of layers of pressure-sensitive films and the surfaces of the rock samples by using a vacuum adsorption technology; s2, dynamically loading pressure on the rock sample, collecting pressure data of different loading stages, and generating distribution condition information of the rock sample contact stress along with loading change in combination with a time axis; before the experiment and in the experiment process, the experiment environment information is adjusted in real time through an environment control device with an intelligent temperature control and humidity control system; and S3, performing 3D reconstruction according to the distribution condition information, and generating a three-dimensional distribution diagram of the rock sample contact stress. According to the scheme, the authenticity of simulation and the precision and accuracy of a measurement result can be improved, and the performance of a rock sample in a complex environment can be truly and accurately reflected.

Description

Technical Field

[0001] The invention relates to the technical field of rock mechanics testing, and in particular to a method for measuring the contact degree and contact stress distribution of a rock sample by using pressure-sensitive paper. Background Art

[0002] In geotechnical engineering and materials science, understanding the contact degree and contact stress distribution of rock samples is of great significance for evaluating the mechanical properties, stability and safety of rocks. The contact degree refers to the ratio of the actual contact area between two contacting bodies to the theoretical contact area, while the contact stress refers to the distribution of pressure applied on the contact surface. These parameters directly affect the shear strength, deformation characteristics and failure mode of rocks.

[0003] Traditional measurement methods mainly rely on force sensors or pressure sensors. Although these devices can provide direct stress values, they often have problems such as high cost, complex operation and limitations. In addition, traditional methods can usually only measure the pressure at a certain point, and it is difficult to obtain the stress distribution of the contact surface in real time. This makes it difficult for engineers to fully understand the behavior of rock samples under different loading conditions in practical applications, limiting the in-depth study of material properties.

[0004] In recent years, pressure-sensitive film, as a new type of testing material, has gradually attracted attention because of its simplicity, economy and ability to intuitively display pressure distribution. The pressure-sensitive property of pressure-sensitive film enables it to change color when subjected to pressure, thereby providing intuitive information about the contact area under different pressures on a visual basis. This property makes pressure-sensitive film an ideal tool for studying contact degree and contact stress distribution.

[0005] Therefore, some studies have tried to use pressure-sensitive materials to measure contact stress, but the existing technology still has some shortcomings: the response of pressure-sensitive films in high-pressure or low-pressure areas is limited, and the measurement accuracy and measurement range are limited; static loading measurements during the measurement process often collect data only once a specific pressure is reached, and cannot reflect the changes in stress distribution during the loading process; the image of the pressure-sensitive film of the measurement result is limited to a two-dimensional image, which is difficult to effectively reflect the pressure distribution on the surface of a complex sample. When the sample has an irregular surface or a hierarchical structure, plane scanning is prone to angle distortion or missing depth information, resulting in a decrease in the accuracy and operability of the measurement results; and the entire rock mechanics experiment is often carried out in a standardized laboratory environment, lacking consideration of real environmental factors, resulting in the experimental results may not truly reflect the performance of the rock sample in a complex environment.

[0006] In summary, the existing methods for measuring the contact degree and contact stress distribution of rock samples have low simulation authenticity, insufficient precision and accuracy of the measurement results, and may not truly and accurately reflect the performance of rock samples in complex environments. Summary of the invention

[0007] The present invention aims to provide a method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper, which can improve the authenticity of simulation, the precision and accuracy of measurement results, and truly and accurately reflect the performance of rock samples in complex environments.

[0008] The present invention provides the following basic scheme: a method for measuring the contact degree and contact stress distribution of a rock sample using pressure-sensitive paper, comprising the following contents:

[0009] S1. The multilayer pressure-sensitive film is placed between the contact surfaces of two rock samples to be tested, and the bubbles on the surface of the multilayer pressure-sensitive film and the rock sample are eliminated by vacuum adsorption technology;

[0010] S2. Dynamically load the rock sample with pressure, collect pressure data at different loading stages, and generate information on the distribution of the rock sample contact stress as it changes with loading, combined with the time axis; and adjust the experimental environment information in real time before and during the experiment through an environmental control device with an intelligent temperature control and humidity control system;

[0011] S3. Perform 3D reconstruction based on the distribution information to generate a three-dimensional distribution map of the rock sample contact stress.

[0012] Furthermore, the multi-layer pressure-sensitive film includes at least three layers of pressure-sensitive film, and the pressure response range of each layer of the pressure-sensitive film is different.

[0013] Furthermore, the vacuum adsorption technology is used to eliminate bubbles on the surface of the multi-layer pressure-sensitive film and the rock sample, including:

[0014] Surface treatment technology is used to grind and process the contact surface between the rock sample and the pressure-sensitive film, so that the flatness of the contact surface reaches the micron level;

[0015] A vacuum adsorption device is used. When a pressure-sensitive film is placed between the contact surfaces of two rock samples to be tested, vacuum adsorption technology is used to remove air, and a bubble monitoring sensor is equipped to provide real-time feedback on bubble formation.

[0016] Further, the S2 includes:

[0017] Dynamic loading device is used to dynamically load pressure on the rock sample;

[0018] A high-resolution optical scanner or sensor array is used to collect the pressure distribution on the pressure-sensitive film at preset time intervals, and the pressure distribution changes in the whole process from initial loading to peak loading are recorded;

[0019] After the pressure data is collected, the pressure images at each moment are superimposed through image processing, and combined with the time axis to generate a time evolution diagram of the pressure distribution, or combined with the time axis to generate time series data of the rock sample pressure distribution; the time evolution diagram of the pressure distribution and the time series data of the rock sample pressure distribution are both distribution information of the rock sample contact stress with loading changes.

[0020] Furthermore, the dynamic loading device can adjust the loading rate and mode; the mode includes: progressive loading, rapid loading and periodic loading.

[0021] Furthermore, before and during the experiment, the experimental environment information is adjusted in real time through an environmental control device with an intelligent temperature control and humidity control system, including:

[0022] Before S1, configure the environmental control device of the intelligent temperature control and humidity control system, and set the experimental environment information;

[0023] During the execution of S2, the rock sample is dynamically loaded with pressure through the dynamic loading device, and the changes in the experimental environment information are monitored in real time.

[0024] Further, the S3 includes:

[0025] Use a 3D laser scanning device or a structured light scanner to scan the surface of the pressure-sensitive film and the rock sample, collect images of different perspectives at multiple angles and multiple positions, generate point cloud information with depth data, and form a 3D model of the surface morphology of the pressure-sensitive film and the rock sample based on the point cloud information; the images include: pressure images and color change images;

[0026] Integrate the pressure images collected from multiple angles, align, register and fuse the data from each angle through 3D reconstruction to form a complete 3D structure;

[0027] Based on the color change image of the pressure-sensitive film, the pressure data is superimposed and combined with the three-dimensional model;

[0028] Image processing algorithms are used for automatic analysis to convert the color change data on the color change image into pressure distribution, which is then superimposed on the three-dimensional model in a color layered manner to generate a three-dimensional distribution map of the contact stress of the rock sample.

[0029] Furthermore, S2 also includes: using a machine learning algorithm to analyze the pressure data collected in real time, automatically identifying the changing pattern of stress distribution, predicting potential damage points, and generating a corresponding early warning report.

[0030] Furthermore, the real-time collected pressure data is analyzed using a machine learning algorithm to automatically identify the changing pattern of stress distribution and predict potential failure points, including:

[0031] Remove noise from the image of real-time pressure data, perform standardization, and convert the image into a numerical stress distribution matrix;

[0032] Based on the stress distribution matrix, identify key features;

[0033] According to the stress distribution matrix, mathematical methods are used to extract stress distribution characteristics;

[0034] Use historical experimental data to establish a prediction model, and learn the correlation between stress distribution and failure points based on key features and stress distribution characteristics;

[0035] Input real-time stress data, and the prediction model outputs the probability of failure points and early warning reports.

[0036] Further, the prediction model is a physically enhanced adaptive integrated prediction model;

[0037] Physically enhanced adaptive integrated prediction model, integrating: SVM, CNN and simulation model;

[0038] Among them, the support vector machine is used for low-dimensional feature data to classify whether the stress distribution is abnormal;

[0039] Convolutional neural networks automatically extract high-dimensional features of pressure-sensitive paper images and identify stress concentration areas;

[0040] Finite element analysis (FEA) is used to calculate the physical field solution of stress distribution and to impose physical constraints on the simulation model.

[0041] Beneficial effects of this scheme: First, this scheme adopts a multi-layer pressure-sensitive film structure to record information of different pressure levels more meticulously, significantly improving the measurement accuracy, so that the resolution and accuracy of pressure data reach a level that cannot be achieved by a single-layer film; the multi-layer film can cover a wide range of pressures, solving the problem of limited response of a single-layer film in high-pressure or low-pressure areas, and realizing full-range measurement from micro-pressure to high-pressure, which is suitable for more complex rock sample mechanical testing; and the vacuum adsorption technology is used to eliminate bubbles on the surface of the multi-layer pressure-sensitive film and the rock sample, preventing the formation of bubbles to ensure gapless contact between the pressure-sensitive film and the surface of the rock sample, thereby further improving the accuracy and consistency of contact stress measurement;

[0042] Secondly, this scheme dynamically loads the rock sample with pressure and collects pressure data at different loading stages. Combined with the time axis, it generates information on the distribution of the rock sample contact stress as it changes with loading. Through dynamic loading analysis, the change process of the rock sample contact stress during loading can be clearly observed, and its response characteristics to pressure changes can be obtained. Dynamic loading can simulate the cyclic stress conditions of repeated loading and unloading, so that researchers can understand the stress conditions and fatigue damage of rock samples in long-term use. In addition, during the dynamic loading process, the stress concentration area of ​​the rock sample is often the potential location of the failure point. Through dynamic loading analysis, the concentrated area in the stress distribution can be discovered in advance, the rock sample failure point can be effectively predicted, and a basis for safety design in engineering applications can be provided. The dynamic loading system can collect data in real time and adjust the loading rate or intensity according to the stress feedback of the rock sample. This dynamic adjustment mechanism can better adapt to the structural characteristics of the rock sample and effectively improve the accuracy of the test results.

[0043] Finally, this scheme performs 3D reconstruction based on the distribution information to generate a three-dimensional distribution map of the contact stress of the rock sample. The three-dimensional reconstruction technology can fully display the spatial distribution of the contact stress of the rock sample, avoiding the limitations of plane images on the three-dimensional structure, greatly improving the readability and intuitiveness of the data, and is particularly suitable for samples with irregular surfaces or porous structures; in the three-dimensional model, different areas of the contact surface can be divided and analyzed separately, so as to perform more detailed mechanical analysis; three-dimensional reconstruction can obtain depth information for each sampling point, avoiding the distortion of pressure information caused by image angle deviation, which makes the collection of pressure data more accurate, especially in the microscopic pressure distribution and edge pressure gradient, showing higher accuracy.

[0044] In addition, before and during the experiment, this solution uses an environmental control device with an intelligent temperature control and humidity control system to adjust the experimental environment information in real time. The environmental factor simulation can be closer to the actual application environment. By controlling the experimental conditions, the measured contact stress and material properties are more realistic and reliable, which can reflect the behavior of the rock sample in actual use. The test data under the same environmental conditions are more consistent, which can improve the comparability and repeatability of the experimental results and help researchers conduct effective comparative analysis between different experiments. The impact of environmental factors on material properties changes dynamically. By simulating different environmental conditions, the stability and reliability of rocks in long-term use can be evaluated, and potential performance degradation and damage risks can be identified in advance.

[0045] In summary, this scheme can improve the realism of simulation, the precision and accuracy of measurement results, and truly and accurately reflect the performance of rock samples in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1It is a flow chart of an embodiment of a method for measuring the contact degree and contact stress distribution of a rock sample by using pressure-sensitive paper according to the present invention;

[0047] Figure 2 It is a front view of arranging MW type pressure sensitive film between two rock samples to be measured in an embodiment of the method for measuring the contact degree and contact stress distribution of rock samples by using pressure sensitive paper of the present invention;

[0048] Figure 3 It is a top view of arranging a MW type pressure sensitive film between two rock samples to be measured in an embodiment of a method for measuring the contact degree and contact stress distribution of rock samples by using pressure sensitive paper of the present invention;

[0049] Figure 4 It is a schematic diagram of using a heat shrink sleeve in an embodiment of a method for measuring the contact degree and contact stress distribution of a rock sample using pressure-sensitive paper according to the present invention;

[0050] Figure 5 A schematic diagram of the pressure-sensitive film structure in an embodiment of a method for measuring the contact degree and contact stress distribution of a rock sample using pressure-sensitive paper according to the present invention;

[0051] Figure 6 A schematic diagram of three layers of pressure-sensitive film in an embodiment of a method for measuring the contact degree and contact stress distribution of a rock sample using pressure-sensitive paper according to the present invention;

[0052] Figure 7 The graph is a pressure-sensitive film pressure-coloring depth curve of the MW type pressure-sensitive film in an embodiment of the method for measuring the contact degree and contact stress distribution of a rock sample by using pressure-sensitive paper of the present invention. DETAILED DESCRIPTION

[0053] The following is further described in detail through specific implementation methods:

[0054] The reference numerals in the drawings of the specification include: MW type pressure-sensitive film 1, rock sample 2, left rock sample 21, right rock sample 22, heat shrink sleeve 3, A type pressure-sensitive film 4, C type pressure-sensitive film 5.

[0055] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0056] In the description of this specification, it should be understood that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to the "upper", "lower", "left", or "right" of another element, it can not only be directly connected to the "upper", "lower", "left", or "right" of another element, but can also be indirectly connected to the "upper", "lower", "left", or "right" of another element through an intermediate element.

[0057] The embodiment is basically as shown in the attached Figure 1 As shown: A method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper, including the following contents:

[0058] S1. Place a multilayer pressure-sensitive film between the contact surfaces of two rock samples 2 (i.e., rock specimens) to be tested. Figure 2 and Figure 3 As shown, the two rock samples 2 are divided into a left rock sample 21 and a right rock sample 22, and a MW type pressure-sensitive film 1 is used, and a vacuum adsorption technology is used to eliminate bubbles on the surface of the multi-layer pressure-sensitive film and the rock sample 2; in other embodiments, a heat shrink sleeve 3 is used to fix the two rock samples 2 to be tested to clamp the multi-layer pressure-sensitive film, such as Figure 4 As shown;

[0059] Wherein the multilayer pressure-sensitive film is a multilayer pressure-sensitive film, such as Figure 5 As shown, A-type pressure-sensitive film 4 and C-type pressure-sensitive film 5 are used, with color-developing particles and colored particles in the middle; this embodiment includes at least three layers of pressure-sensitive film, such as Figure 6 As shown, the pressure response range of each layer of pressure-sensitive film is different, so that the pressure changes in the contact area can be recorded separately. As the pressure changes, the color of the pressure-sensitive film will also change, such as Figure 7 As shown; Specifically, in this embodiment, three layers of pressure-sensitive film are provided, and the measuring range of each layer is low, medium and high, respectively, covering the area from micro pressure to large pressure. The first layer (low-pressure layer) is used to record the pressure response of 2.5-10MPa, the second layer (medium-pressure layer) is used to record the pressure response of 10-50MPa, and the third layer (high-pressure layer) is used to record the pressure response of 50-130MPa. When the experiment is loaded, the information of different pressure intervals will be reflected in the color changes of different layers of film. By scanning and processing the data of each layer, an accurate layered pressure distribution map can be obtained;

[0060] Traditional pressure-sensitive films usually adopt a single-layer structure, and their pressure response is mainly concentrated in a specific pressure range. This single-layer film has certain limitations in practical applications, especially when dealing with complex pressure fields. When the pressure difference between different contact areas is large, it is difficult for a single-layer film to accurately record the pressure distribution of high-pressure and low-pressure areas at the same time; in some rock mechanics experiments, especially in rock sample tests with concentrated stress or multi-layer structures, the response range of a single film is difficult to cover the global pressure data, resulting in the loss or inaccuracy of some pressure information;

[0061] The multi-layer pressure-sensitive film of this scheme is divided into multiple layers in the pressure-sensitive layer, and each layer has a different pressure response range. This structure can collect the pressure distribution separately according to high and low levels, so that the pressure responses of high-pressure and low-pressure areas can be accurately fed back within the adapted range. Each layer of pressure-sensitive material is designed with different pressure sensitivity intervals according to its characteristics through a unique formula and material processing method. The multi-layer design can capture pressure data from low pressure to high pressure in all directions, which is suitable for pressure distribution detection of rock sample 2 under different loading conditions.

[0062] In addition, multi-layer pressure-sensitive films use polymer materials with optimized formulas, such as PRESCALE, including: substrate (support): usually polyester film, such as polyethylene terephthalate (PET), is used as the base material of the film to provide the necessary mechanical strength and flexibility; pressure-sensitive layer: this layer contains microcapsules and polymer matrix; microcapsules: internally encapsulate electron-donating dye precursors and solvents; polymer matrix: composed of polymer compounds with a molecular weight of more than 1000, providing structural support and ensuring uniform distribution of microcapsules; color developer layer: contains electron-accepting compounds, such as metal salts of salicylic acid or acidic clay, which chemically react with the dye released by the microcapsules to produce a visible red color; when the film is subjected to pressure, the microcapsules rupture, releasing the dye, which reacts with the color developer to form a red mark. The depth of color is proportional to the pressure, which can be used to measure the distribution and size of pressure. In addition, the wall material of the microcapsule may contain polyurethane urea or polyurethane to ensure its response characteristics in different pressure ranges. The selection and combination of these polymer materials enable the pressure measurement film to provide accurate pressure distribution measurement in a wide pressure range (0.006-300MPa). The layers of a piece of pressure-sensitive film are isolated by gas in tiny gaps to enhance the response sensitivity and resistance to environmental interference.

[0063] The vacuum adsorption technology is used to eliminate bubbles on the surface of the multi-layer pressure-sensitive film and the rock sample 2, including:

[0064] The contact surface between the rock sample 2 and the pressure-sensitive film is polished and processed using surface treatment technology to ensure that the flatness of the contact surface reaches the micron level;

[0065] A vacuum adsorption device is used. When the pressure-sensitive film is placed between the contact surfaces of the two rock samples 2 to be tested, the vacuum adsorption technology is used to remove air to prevent the formation of bubbles and ensure that there is no gap between the pressure-sensitive film and the surface of the rock sample 2, thereby improving the accuracy and consistency of the contact stress measurement. In this embodiment, the vacuum adsorption technology is realized by a vacuum adsorption device. The vacuum adsorption device can automatically adjust the working pressure within the range of -0.1MPa to -0.05MPa, and is equipped with a bubble monitoring sensor for real-time feedback of bubble formation to ensure the integrity of the contact surface.

[0066] The vacuum adsorption technology not only eliminates tiny bubbles, but also effectively reduces the dynamic error in the measurement process. By ensuring the gapless contact between the contact surface of the pressure-sensitive film and the rock sample 2, the fitting accuracy is improved, and the response uniformity of the pressure-sensitive film in the high-precision test is further optimized, making the final contact stress diagram more realistic and continuous. Compared with the traditional contact method, it is difficult to avoid the data inhomogeneity caused by bubbles, and the vacuum adsorption technology solves this problem and improves the reliability of the measurement.

[0067] S2, dynamically load pressure on rock sample 2, collect pressure data at different loading stages, and generate distribution information of contact stress of rock sample 2 as it changes with loading in combination with the time axis; and before and during the experiment, adjust the experimental environment information in real time through an environmental control device with an intelligent temperature control and humidity control system, where the experimental environment information includes: temperature, humidity and chemical corrosion conditions;

[0068] Dynamic loading technology is used to collect contact stress data (i.e., pressure data) in real time through a programmable loading device. The loading device has an adjustable loading rate and mode, and can simulate various experimental requirements such as progressive loading, rapid loading, and cyclic loading;

[0069] Traditional pressure-sensitive film measurements are usually carried out under a static loading condition, that is, after the pressure loading is completed, the contact stress and distribution data are recorded. However, rocks often undergo a dynamic loading process in the actual environment. For example, under conditions of geological structure changes, vibrations during mining, and periodic stress changes, the contact stress distribution of the rock will continue to change with time and loading rate. In order to better simulate the dynamic loading process of rocks in the actual environment, this scheme dynamically loads pressure on rock sample 2 and implements data collection to form a dynamic loading analysis. The dynamic loading analysis can not only help observe the pressure change process at different loading stages, but also can be used to predict the performance of rock sample 2 under long-term dynamic stress conditions.

[0070] Dynamic loading analysis collects pressure data at different loading stages in real time, combines it with the time axis, and plots the distribution information of the contact stress of rock sample 2 as it changes with loading. This can capture and analyze the evolution of contact pressure during loading, thereby providing reliable data support for the fatigue properties of the material, the dynamic changes of stress concentration, and the failure mode. Through gradual loading and real-time monitoring, the changing trend of pressure with loading time can be dynamically observed, which is particularly important for understanding the behavior pattern of the material.

[0071] The specific implementation process is as follows:

[0072] A dynamic loading device is used to dynamically load pressure on the rock sample 2, wherein the dynamic loading device has an adjustable loading rate and mode, which can simulate various experimental requirements such as progressive loading, rapid loading and cyclic loading. In this embodiment, the pressure is increased by 0.5 MPa per minute and gradually loaded to 50 MPa, or a fluctuating pressure change is set to simulate the cyclic stress process in a real scene; the dynamic loading device controls the frequency and intensity of the applied pressure through programming, that is, the amplitude frequency of the periodic ground stress wave, to simulate geological stress, periodic pressure and other scenes; wherein the mode includes but is not limited to: progressive loading, rapid loading and periodic loading, to simulate dynamic stress conditions in different geological conditions and engineering applications;

[0073] Using a high-resolution optical scanner or sensor array, the pressure distribution on the pressure-sensitive film is collected at a preset time interval (e.g., once per second), and the pressure distribution changes in the entire process from initial loading to peak loading are recorded;

[0074] After the pressure data is collected, the pressure images at each moment are superimposed through image processing, and combined with the time axis to generate a pressure distribution evolution diagram over time, or combined with the time axis to generate time series data of the pressure distribution of rock sample 2, so that the stress change at each time point is clearly visible; the pressure distribution evolution diagram over time and the time series data of the pressure distribution of rock sample 2 are both distribution information of the contact stress of rock sample 2 with loading changes.

[0075] In addition, before and during the experiment, the temperature, humidity and chemical corrosion conditions of the experimental environment are adjusted in real time through an environmental control device with an intelligent temperature control and humidity control system to simulate the impact of environmental factors on contact stress in actual scenarios.

[0076] In rock mechanics and material testing, the performance of rock sample 2 is often significantly affected by environmental factors, including temperature, humidity, chemical corrosion, etc. These factors cannot be ignored in practical applications, especially in geological engineering, mining and oil and gas resource development. Rock materials often face a changing external environment. The influence of these environmental factors on contact stress and material properties is crucial to obtaining real and reliable experimental data.

[0077] In order to better simulate the situation of rocks in the actual environment, this program simulates environmental factors. Through experimental design, the experimental conditions are adjusted in a controlled environment to simulate the influence of temperature, humidity and other environmental changes in real scenes on the performance and contact stress distribution of rock sample 2. The environmental control device can be used to monitor and adjust the experimental conditions in real time during the experiment, and record the influence of environmental factors on the contact stress measurement results. It can not only help researchers understand how environmental changes affect the mechanical properties of rocks, but also provide data support for subsequent engineering applications to ensure the safety and stability of materials in various environments.

[0078] The specific implementation process is as follows: before S1 (before the experiment), configure the environmental control device of the intelligent temperature control and humidity control system, and set the experimental environment information; in this embodiment, a test box with a temperature control and humidity control system is used. Before the test, a specific temperature range (such as -10°C to 50°C) and humidity level (such as 20% to 80%) are set according to the actual working conditions to preset the experimental conditions;

[0079] During the execution of S2 (during the experiment), the rock sample 2 is dynamically loaded with pressure by the dynamic loading device, and the changes in the experimental environment information are monitored in real time. In this embodiment, a multi-point temperature and humidity sensor is used to collect the experimental environment information to ensure that the environmental conditions remain stable at different stages of pressure loading, and the impact of environmental changes on the contact stress of the rock sample 2 is recorded;

[0080] During the data analysis phase, statistical analysis was performed on the monitored experimental environment information and the distribution information of the contact stress of rock sample 2 as it changes with loading, and the changes in pressure distribution under different temperature and humidity conditions were compared. By establishing a mathematical model, the influence of the experimental environment information (environmental factors) on the contact stress and deformation characteristics of rock sample 2 was analyzed, thereby extracting the law of changes in rock performance under different conditions.

[0081] S3. Perform 3D reconstruction based on the distribution information to generate a three-dimensional distribution map of the contact stress of the rock sample 2.

[0082] The traditional pressure-sensitive film method usually uses plane scanning technology to obtain contact stress distribution data. However, when the surface of the rock sample 2 is irregular and has many layers, the plane scanning method alone often cannot accurately reflect the overall picture of the stress distribution; especially when the rock sample 2 has uneven surface features, complex microstructures or pores, a single plane image is difficult to meet the accuracy requirements of the data;

[0083] In order to obtain a more accurate contact stress distribution, this scheme performs 3D reconstruction, which uses three-dimensional scanning or computer image reconstruction technology to spatially reconstruct the surface morphology and stress distribution of the pressure-sensitive film and rock sample 2; the pressure response image on the pressure-sensitive film is collected from multiple angles, and the collected two-dimensional image is spatially reconstructed in combination with a three-dimensional reconstruction algorithm, and finally a three-dimensional pressure distribution map with depth information is generated, so that the contact stress distribution of the rock sample 2 and the pressure-sensitive film can be presented in a three-dimensional form, accurately reflecting the pressure conditions at different levels and regions, and providing a higher analysis dimension for the multi-level structure of the rock sample 2.

[0084] The specific implementation process is as follows:

[0085] Use a three-dimensional laser scanning device or a structured light scanner to scan the surface of the pressure-sensitive film and the rock sample 2, collect images of different perspectives through multiple angles and multiple positions, generate point cloud information with depth data, and form a fine three-dimensional model of the surface morphology of the pressure-sensitive film and the rock sample 2 according to the point cloud information; the image includes: a pressure image and a color change image; in this embodiment, the multiple angles and multiple positions are set according to the needs, and in this embodiment, the front, side, and surround scanning are performed;

[0086] Integrate the pressure images collected from multiple angles, align, register and fuse the data from each angle through 3D reconstruction to form a complete 3D structure;

[0087] Based on the color change image of the pressure-sensitive film, the pressure data is superimposed and combined with the three-dimensional model;

[0088] Image processing algorithms are used for automatic analysis to convert the color change data on the color change image into pressure distribution, which is then superimposed on the three-dimensional model in a color layered manner to generate a three-dimensional distribution map of the contact stress of rock sample 2.

[0089] The resolution of the image processing process is not less than 300dpi to ensure that the slight surface morphology changes and contact stress distribution are accurately reflected in the three-dimensional model; in the final three-dimensional distribution map, different pressure areas are distinguished according to depth and color, and the spatial distribution and gradient changes of pressure can be clearly seen. By rotating and scaling the three-dimensional model, the stress distribution can be observed and analyzed from all angles, which helps to identify pressure concentration areas and stress paths under complex surfaces.

[0090] In addition, the S2 also includes: using a machine learning algorithm to analyze the real-time collected pressure data, automatically identifying the changing rules of stress distribution, predicting potential damage points, and generating corresponding early warning reports;

[0091] Specifically, the noise in the image is removed and standardized, and the image of the real-time collected pressure data is converted into a numerical stress distribution matrix for use by the machine learning algorithm;

[0092] Based on the stress distribution matrix, identify key features such as stress peak area, gradient change, stress concentration area, and the trend of pressure distribution over time;

[0093] According to the stress distribution matrix, mathematical methods are used to extract stress distribution characteristics, such as Fourier transform, principal component analysis (PCA), etc.

[0094] Use historical experimental data (including rock failure experimental data and pressure data) to establish a prediction model, and learn the correlation between stress distribution and failure points based on key features and stress distribution characteristics;

[0095] Input real-time stress data, and the prediction model outputs the probability of failure points and early warning reports.

[0096] The prediction model can use traditional machine learning algorithms, such as SVM, random forest, GBDT, etc. These methods are fast and effective, but have limited performance in high-dimensional data and complex nonlinear relationships. Therefore, this scheme sets up an improved prediction model: a physically enhanced adaptive integrated prediction model;

[0097] The physically enhanced adaptive integrated prediction model achieves accurate prediction of rock sample stress distribution through deep integration of physical mechanics models and machine learning. It uses integrated learning to improve the prediction robustness of multiple algorithms, dynamically adjusts model parameters through adaptive optimization, and improves adaptability and accuracy under different rock sample conditions.

[0098] Physically enhanced adaptive integrated prediction model integration: SVM, CNN and simulation models;

[0099] Among them, support vector machine (SVM): is suitable for low-dimensional feature data and classifies whether the stress distribution is abnormal;

[0100] Convolutional Neural Network (CNN): Automatically extract high-dimensional features of pressure-sensitive paper images and identify stress concentration areas;

[0101] The physical field solution of stress distribution is calculated by finite element analysis (FEA) to provide physical constraints of the model, where FEA is the simulation model.

[0102] This model dynamically adjusts the weights and hyperparameters in the integrated model to maintain optimal performance under different rock samples and stress conditions, and dynamically adjusts model parameters based on real-time collected data feedback (e.g., automatically updating the model for new rock sample types);

[0103] The prediction process for predicting potential damage points is as follows:

[0104] Input real-time stress data (experiment + simulation), SVM and CNN output risk scores respectively, integrate the results, and combine with finite element analysis verification to ensure that the risk points conform to physical laws;

[0105] Corresponding early warning mechanism:

[0106] High-risk point marking: Mark areas where stress exceeds physical thresholds or where model prediction scores are high; generate prediction reports including risk areas, failure probability scores, and time predictions.

[0107] This scheme measures the contact stress of the contact surface of rock sample 2 through multi-layer pressure-sensitive film, and uses vacuum adsorption technology to ensure that rock sample 2 and pressure-sensitive film maintain uniform contact during dynamic loading to eliminate bubble interference; at the same time, 3D reconstruction technology is used for image processing and stress distribution analysis to make the calculation results of contact stress more accurate, as follows:

[0108] 1. This solution improves measurement accuracy and expands measurement range: The multi-layer pressure-sensitive film structure can record information at different pressure levels in more detail, significantly improving measurement accuracy, and making the resolution and accuracy of pressure data reach a level that cannot be achieved with a single-layer film. Multi-layer film can cover a wide range of pressures, solving the problem of limited response of single-layer film in high-pressure or low-pressure areas, and achieving full-range measurement from micro-pressure to high-pressure, which is suitable for more complex mechanical testing of rock samples 2.

[0109] Existing pressure-sensitive film technology has the limitation of limited response range and difficulty in taking into account high and low pressure areas in pressure distribution measurement, and can usually only measure within a fixed pressure range. In contrast, the design of multi-layer pressure-sensitive film enables it to be finely layered according to pressure changes, fully record pressure information at different levels, and form seamless pressure distribution data. This breakthrough gives it a significant advantage in high-precision and complex pressure testing, especially in the fields of rock mechanics and material mechanics, and helps to fully and accurately present complex pressure distribution fields.

[0110] In particular, multi-layer pressure-sensitive films can effectively improve the accuracy of measurement data and distinguish accurate data through stratification; the design of multi-layer pressure-sensitive films divides different pressure intervals into independent layers for recording, solving the problem that single-layer pressure-sensitive films cannot accurately capture small pressure changes when multiple pressure intervals overlap. Each layer of pressure-sensitive film only responds to its designed pressure range, so that when pressure is transmitted to different layers, it can reflect the real pressure changes with higher accuracy.

[0111] Assuming that a single-layer pressure-sensitive film can only record a pressure range of 10-50MPa, in the experiment, complex pressure gradient changes may be encountered. For example, the pressure of the rock formation changes very slightly between 30-40MPa and 40-50MPa, but on a single-layer film, these subtle changes may be ignored or affected by the averaging of the entire pressure range, resulting in errors in the measurement results. In this case, the recorded pressure data can only be a rough average value within this range, and it is impossible to subdivide each precise pressure change. The error is usually between ±5-10%. Among them, the error sources of single-layer pressure-sensitive films are: first, the pressure range is wide. The working pressure range of single-layer films is generally wide (for example, 10-50MPa). When the actual pressure distribution changes within this range, the measured data may fluctuate greatly; second, nonlinear response. The response of pressure-sensitive films is often not completely linear. When the pressure changes greatly, the measurement error may increase with the increase of pressure, especially at the boundary (for example, the transition area between 10MPa and 50MPa).

[0112] Multilayer pressure-sensitive films, on the other hand, subdivide the pressure range into multiple intervals, such as low pressure (2.5-10MPa), medium pressure (10-50MPa), and high pressure (50-130MPa). Each layer of pressure-sensitive film only responds to its specified pressure range, thereby avoiding errors caused by aliasing of pressure intervals. For example, in the 10-50MPa interval, the pressure change speeds in the low-pressure and high-pressure areas are different. If a single layer of pressure-sensitive film responds to the entire interval, it is impossible to accurately distinguish the difference between the two sub-intervals. In multilayer films, the low-pressure layer focuses on capturing pressure changes between 2.5-10MPa, the medium-pressure layer focuses on capturing pressure changes between 10-50MPa, and the high-pressure layer is responsible for the pressure response of 50-130MPa. The design of each layer of film is precisely matched to the response pressure interval, eliminating the aliasing effect and improving the accuracy of the measurement. Multilayer pressure-sensitive films can effectively reduce data errors and provide more accurate pressure distribution information by focusing on a relatively narrow pressure interval for each layer. The reason for the reduction in errors of multi-layer films is that the response range of each layer of pressure-sensitive film is smaller, which means that the pressure changes in each layer of pressure-sensitive film will not be too drastic and the pressure response will be smoother. The error range of each layer of pressure-sensitive film is smaller. For example, in the low-pressure range (2.5-10MPa), due to the smaller pressure range, the relationship between the color change of the pressure-sensitive film and the pressure change is more linear and predictable, and the error is controlled between ±2-5%. In the medium-pressure range (10-50MPa) and the high-pressure range (50-130MPa), the error is also greatly reduced because the pressure range of each layer of film is relatively narrow and the response is more precise.

[0113] The design of multi-layer pressure-sensitive film enables the details of each pressure interval to be recorded independently, thus providing more pressure data points. For example, in the experiment, the specific response data of each layer in the low-pressure interval, medium-pressure interval and high-pressure interval can be obtained, so that a more detailed pressure distribution diagram can be obtained. Take the actual data recorded in the experiment as an example:

[0114] Pressure data recorded by single layer film:

[0115] 10MPa: 10±1MPa;

[0116] 20MPa: 20±2MPa;

[0117] 30MPa: 30±3MPa;

[0118] 40MPa: 40±4MPa;

[0119] 50MPa: 50±5MPa;

[0120] The total error range is between ±5-10%, which may lead to the loss of inaccurate pressure points, especially in places with small pressure gradients. The accumulation of errors may affect the accuracy of the overall data.

[0121] Pressure data recorded by multi-layer film:

[0122] Low pressure layer (2.5-10MPa):

[0123] 2.5MPa: 2.5±0.2MPa;

[0124] 5MPa: 5±0.3MPa;

[0125] 7.5MPa: 7.5±0.4MPa;

[0126] 10MPa: 10±0.5MPa;

[0127] Error: ±2-5%;

[0128] Medium pressure layer (10-50MPa):

[0129] 10MPa: 10±0.5MPa;

[0130] 20MPa: 20±1MPa;

[0131] 30MPa: 30±1.5MPa;

[0132] 40MPa: 40±2MPa;

[0133] 50MPa: 50±2.5MPa;

[0134] Error: ±2-5%;

[0135] High pressure layer (50-130MPa):

[0136] 50MPa: 50±1MPa;

[0137] 70MPa: 70±2MPa;

[0138] 90MPa: 90±3MPa;

[0139] 110MPa: 110±4MPa;

[0140] 130MPa: 130±5MPa;

[0141] Error: ±2-5%;

[0142] From the above experimental data, it can be seen that through this layering method, the overall error is reduced by 30%-50%, and the accuracy of each layer is improved, so that slight changes in different pressure ranges can be accurately recorded.

[0143] Multilayer pressure-sensitive film is particularly suitable for stress analysis of complex structural rock samples2, such as shale, sandstone and dense rock. Since it can record data of different pressure areas in layers, it has broad application prospects in unconventional oil and gas resource development, material fatigue failure analysis and real-time monitoring of engineering sites. At the same time, in geological exploration and geotechnical engineering, it can also be used to analyze formation stress and contact pressure to provide more accurate structural safety assessment data.

[0144] In practical applications, multi-layer pressure-sensitive films enable the improvement of measurement accuracy and the acquisition of higher quality experimental data, especially in the following aspects:

[0145] Accurate pressure distribution map: Multilayer pressure-sensitive film can provide high-precision layered pressure maps, helping researchers to accurately analyze the distribution of pressure changes at different depths and stress areas, and optimize mining plans or engineering designs;

[0146] More reliable engineering decisions: More accurate pressure measurements can help engineers in oil and gas development, geological exploration and other fields better understand underground pressure distribution, reduce misjudgments, and avoid equipment damage or unstable operations caused by excessive or low pressure;

[0147] Improved safety: Under extreme pressure conditions (such as oil and gas wells or mines), the pressure changes can be accurately monitored, abnormalities can be detected in advance and measures can be taken, thus greatly reducing the probability of accidents.

[0148] 2. This solution deeply understands the dynamic response mechanism of rock materials and predicts the failure point:

[0149] Through dynamic loading analysis, the change process of contact stress of rock sample 2 during loading can be clearly observed, and its response characteristics to pressure changes can be obtained. For example, the rigidity, elasticity and plasticity of the material under step-by-step loading conditions can be analyzed. Dynamic loading can simulate cyclic stress conditions of repeated loading and unloading, so that researchers can understand the stress conditions and fatigue damage of rock sample 2 during long-term use. Dynamic analysis data can be used to evaluate the fatigue strength and failure mode of materials, providing rich data support for rock mechanics and materials science. During dynamic loading, the stress concentration area of ​​rock sample 2 is often the potential location of the failure point. Through dynamic analysis, the concentrated area in the stress distribution can be discovered in advance, the failure point of rock sample 2 can be effectively predicted, and a basis for safe design in engineering applications can be provided. The dynamic loading system can collect data in real time and adjust the loading rate or force according to the stress feedback of rock sample 2. This dynamic adjustment mechanism can better adapt to the structural characteristics of rock sample 2 and effectively improve the accuracy of the test results.

[0150] Static loading measurements in the prior art often collect data only once a specific pressure is reached, and cannot reflect changes in stress distribution during the loading process. Therefore, it is difficult to conduct a comprehensive analysis of the dynamic behavior of rock sample 2 (such as fatigue characteristics, stress concentration development, etc.). In contrast, the dynamic loading analysis of this scheme can obtain continuous loading data and present the pressure state at each moment in a time series, making up for the problem of missing data on the time axis of traditional static measurement methods. Through dynamic loading analysis, the time resolution of the contact stress distribution diagram can be significantly improved, making the test method more in line with the actual pressure scenarios in geotechnical engineering. Dynamic loading provides rich information on the integrity and changing trends of pressure distribution, which is a unique innovation that cannot be achieved by traditional static testing methods.

[0151] Dynamic loading analysis can be widely used in rock mechanics research in oil and gas resource development, formation stability analysis in geological engineering, and fatigue strength analysis of various materials under cyclic stress. This technology has extremely high application value in scenarios such as earthquake simulation, rock stability assessment during mining, and material fatigue life prediction. In addition, in civil engineering such as bridges, tunnels, and dams, dynamic loading analysis can also be used to evaluate the performance of structural materials under long-term stress conditions, providing a scientific basis for the design and maintenance of large structures.

[0152] 3. Three-dimensional presentation of pressure distribution and easy partition analysis: Three-dimensional reconstruction technology can fully display the spatial distribution of contact stress of rock sample 2, avoiding the limitations of plane images on three-dimensional structures, greatly improving the readability and intuitiveness of data, and is particularly suitable for samples with irregular surfaces or porous structures. In the three-dimensional model, different areas of the contact surface can be divided and analyzed separately. For example, different joints, cracks or pore areas in rock sample 2 can be extracted separately, and their pressure distribution can be statistically analyzed separately, so as to conduct more detailed mechanical analysis. Three-dimensional reconstruction can obtain depth information for each sampling point, avoiding the distortion of pressure information caused by image angle deviation. This makes the collection of pressure data more accurate, especially in microscopic pressure distribution and edge pressure gradient. The three-dimensional reconstructed image supports multiple viewing angles such as rotation and scaling, which is convenient for observing the contact stress distribution of rock sample 2 from any angle. This advantage can provide richer detailed information when analyzing phenomena such as pressure concentration points and crack formation, helping researchers to explore material properties in depth.

[0153] Existing pressure-sensitive film technology is limited to two-dimensional images, which makes it difficult to effectively reflect the pressure distribution on the surface of complex samples. When the sample has an irregular surface or a hierarchical structure, plane scanning is prone to angle distortion or lack of depth information, resulting in reduced accuracy and operability of the measurement results. Three-dimensional reconstruction can obtain depth data from multiple angles, making up for the shortcomings of the two-dimensional image measurement method, making the contact stress data more complete and three-dimensional, and suitable for complex samples that require fine analysis.

[0154] Compared with existing technologies, high-precision 3D reconstruction not only improves the spatial resolution of contact stress distribution maps, but also greatly expands the application scope of this technology, making experimental results in geology, rock mechanics and other fields more accurate, and providing a more adaptable and refined measurement tool for the surface structure and pressure data of rock sample 2.

[0155] High-precision 3D reconstruction can be widely used in stress analysis scenarios of complex surface rock samples2, such as rock formation analysis in unconventional oil and gas resource development, seismic simulation tests, underground structure safety assessment, etc., especially in experiments with porous and multi-layered structural materials such as shale, sandstone, and dense rock. These materials often have complex surface features and require high three-dimensional analysis of stress distribution. By introducing 3D reconstruction technology in contact stress measurement, reliable theoretical support and experimental data can be provided for rock formation stability analysis, crack extension path identification, etc., providing a scientific basis for oil and gas extraction and the safe use of underground resources.

[0156] 4. Improve the authenticity of experimental results and enhance the comparability of data: Environmental factor simulation can be closer to the actual application environment. By controlling the experimental conditions, the measured contact stress and material properties are more realistic and reliable, and can reflect the behavior of rock sample 2 during actual use. The test data conducted under the same environmental conditions are more consistent, which can improve the comparability and repeatability of experimental results and help researchers conduct effective comparative analysis between different experiments. The impact of environmental factors on material properties is dynamic. By simulating different environmental conditions, the stability and reliability of rocks in long-term use can be evaluated, and potential performance degradation and damage risks can be identified in advance.

[0157] Existing rock mechanics experiments are often conducted in standardized laboratory environments, lacking consideration of real environmental factors, resulting in the experimental results not being able to truly reflect the performance of rock sample 2 in a complex environment. Environmental factor simulation technology breaks the limitations of traditional methods by introducing variables such as temperature and humidity during the experiment, making the experimental conditions more realistic and able to more comprehensively evaluate the stress distribution and mechanical properties of rock sample 2. Compared with traditional static testing methods, environmental factor simulation provides a new perspective for contact stress testing, allowing the behavior of materials in different environments to be systematically studied, providing a scientific basis for material selection and engineering design in practical applications.

[0158] Environmental factor simulation has broad application prospects in many fields, especially in geotechnical engineering, geological exploration, mining development, oil and gas extraction, etc. This technology can be used to study the impact of groundwater level changes and temperature fluctuations on rock stability and stress state, and provide support for material performance evaluation in complex environments.

[0159] In addition, with the increasing severity of climate change and environmental problems, the durability research of building materials and infrastructure is becoming more and more important. By introducing environmental factor simulation, the performance of materials under different climatic conditions can be pre-evaluated to ensure their safety and reliability in harsh environments. In the future, the importance of this technology in rock mechanics, materials science and engineering applications will become more and more prominent.

[0160] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for measuring the contact degree and contact stress distribution of a rock sample using pressure-sensitive paper, characterized in that: It includes the following: S1. The multilayer pressure-sensitive film is placed between the contact surfaces of two rock samples to be tested, and the bubbles on the surface of the multilayer pressure-sensitive film and the rock sample are eliminated by vacuum adsorption technology; S2. Dynamically load the rock sample with pressure, collect pressure data at different loading stages, and generate information on the distribution of the rock sample contact stress as it changes with loading, combined with the time axis; and adjust the experimental environment information in real time before and during the experiment through an environmental control device with an intelligent temperature control and humidity control system; S3. Perform 3D reconstruction based on the distribution information to generate a three-dimensional distribution map of the rock sample contact stress.

2. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: The multi-layer pressure-sensitive film comprises at least three layers of pressure-sensitive film, and each layer of the pressure-sensitive film has a different pressure response range.

3. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: The vacuum adsorption technology is used to eliminate bubbles on the surface of the multi-layer pressure-sensitive film and the rock sample, including: Surface treatment technology is used to grind and process the contact surface between the rock sample and the pressure-sensitive film, so that the flatness of the contact surface reaches the micron level; A vacuum adsorption device is used. When a pressure-sensitive film is placed between the contact surfaces of two rock samples to be tested, vacuum adsorption technology is used to remove air, and a bubble monitoring sensor is equipped to provide real-time feedback on bubble formation.

4. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: The S2 comprises: Dynamic loading device is used to dynamically load pressure on the rock sample; A high-resolution optical scanner or sensor array is used to collect the pressure distribution on the pressure-sensitive film at preset time intervals, and the pressure distribution changes in the whole process from initial loading to peak loading are recorded; After the pressure data is collected, the pressure images at each moment are superimposed through image processing, and combined with the time axis to generate a time evolution diagram of the pressure distribution, or combined with the time axis to generate time series data of the rock sample pressure distribution; the time evolution diagram of the pressure distribution and the time series data of the rock sample pressure distribution are both distribution information of the rock sample contact stress with loading changes.

5. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 4, characterized in that: The dynamic loading device can adjust the loading rate and mode; The modes include: progressive loading, rapid loading and cyclic loading.

6. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: Before and during the experiment, the environment control device with intelligent temperature control and humidity control system is used to adjust the experimental environment information in real time, including: Before S1, configure the environmental control device of the intelligent temperature control and humidity control system, and set the experimental environment information; During the execution of S2, the rock sample is dynamically loaded with pressure through the dynamic loading device, and the changes in the experimental environment information are monitored in real time.

7. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: The S3 includes: Use a 3D laser scanning device or a structured light scanner to scan the surface of the pressure-sensitive film and the rock sample, collect images of different perspectives at multiple angles and multiple positions, generate point cloud information with depth data, and form a 3D model of the surface morphology of the pressure-sensitive film and the rock sample based on the point cloud information; the images include: pressure images and color change images; Integrate the pressure images collected from multiple angles, align, register and fuse the data from each angle through 3D reconstruction to form a complete 3D structure; Based on the color change image of the pressure-sensitive film, the pressure data is superimposed and combined with the three-dimensional model; Image processing algorithms are used for automatic analysis to convert the color change data on the color change image into pressure distribution, which is then superimposed on the three-dimensional model in a color layered manner to generate a three-dimensional distribution map of the contact stress of the rock sample.

8. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 1, characterized in that: The S2 also includes: using a machine learning algorithm to analyze the pressure data collected in real time, automatically identifying the changing rules of stress distribution, predicting potential damage points, and generating corresponding early warning reports.

9. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 8, characterized in that: The real-time collected pressure data is analyzed using a machine learning algorithm to automatically identify the changing pattern of stress distribution and predict potential failure points, including: Remove noise from the image of real-time pressure data, perform standardization, and convert the image into a numerical stress distribution matrix; Based on the stress distribution matrix, identify key features; According to the stress distribution matrix, mathematical methods are used to extract stress distribution characteristics; Use historical experimental data to establish a prediction model, and learn the correlation between stress distribution and failure points based on key features and stress distribution characteristics; Input real-time stress data, and the prediction model outputs the probability of failure points and early warning reports.

10. The method for measuring the contact degree and contact stress distribution of rock samples using pressure-sensitive paper according to claim 9, characterized in that: The prediction model is a physically enhanced adaptive integrated prediction model; Physically enhanced adaptive integrated prediction model, integrating: SVM, CNN and simulation model; Among them, the support vector machine is used for low-dimensional feature data to classify whether the stress distribution is abnormal; Convolutional neural networks automatically extract high-dimensional features of pressure-sensitive paper images and identify stress concentration areas; Finite element analysis (FEA) is used to calculate the physical field solution of stress distribution and to impose physical constraints on the simulation model.

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