Automated Testing System and Method for Shear Strength of Mine Backfill

Abstract

The present invention relates to the technical field of material mechanics testing, specifically an automated testing system and method for the shear strength of mine backfill. The system includes: a critical state identification module that collects real-time data of the shear force and shear displacement of the mine backfill during the shear strength test of the mine backfill, converts it into a curve representation, calculates the gradient mutation points of the curve, and marks the key state change positions during the shear process with reference to the gradient mutation points to obtain the parameter characteristics at the moment of shear failure. In the present invention, by collecting the dynamic data of the shear force and shear displacement in real time and converting them into a shear curve, accurately calculating the gradient mutation points in the curve, marking the key state changes during the shear process, and identifying the critical state where the material changes from shear bearing capacity to structural instability, it provides a key basis for the analysis of the shear strength.

Description

Technical Field

[0001] The present invention relates to the technical field of material mechanics testing, and particularly to an automated testing system and method for the shear strength of mine backfill bodies. Background Art

[0002] The technical field of material mechanics testing includes related technologies for measuring and analyzing the mechanical properties of materials under external forces. The core content of this technical field is to study performance parameters such as the strength, deformation, and stability of materials. By testing and analyzing the mechanical characteristics of materials under different loading conditions, it provides important data support for engineering design, structural safety assessment, and material modification.

[0003] Among them, the automated testing system for the shear strength of mine backfill bodies is a special device for measuring the shear strength of mine filling materials under the action of shear forces. This system aims at the shear performance testing of mine backfill materials. By placing the backfill body sample in a shear test device and applying a certain shear force and normal pressure, it records the mechanical parameters in the failure state to complete the measurement of the shear strength. Specifically, an automated loading device is used to accurately apply and control the shear force and normal pressure, and at the same time, sensors are equipped to collect mechanical data in real time, and through automatic calculation and recording, the entire testing process is completed.

[0004] In the prior art, it is difficult to accurately capture the key turning point from load-bearing to instability of materials during the shear strength testing process. Usually, only the maximum shear force and displacement values can be used for analysis, and the critical state of the materials cannot be effectively marked. For example, during the process of the backfill body being sheared and damaged, the prior art methods cannot dynamically analyze the change trend of the curve based on real-time data, resulting in a lag in the identification of the critical state. In addition, in the prior art, it is difficult to analyze the dynamic laws of the shear failure stage segment by segment. For example, it is impossible to accurately extract the characteristics of shear force attenuation and shear displacement growth, and it is also difficult to reveal the synergistic relationship between the two. For the local stress concentration phenomenon during the testing process, the prior art lacks flexible adjustment of the change ratio and path, which may lead to uneven loading, thereby affecting the stability and accuracy of the data. Taking stress concentration as an example, when the local shear force surges, the prior art methods cannot intervene in the change of mechanical parameters in time, which may cause deviation of the test results. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies existing in the prior art, and to propose an automated testing system and method for the shear strength of mine backfill bodies.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: The automated testing system for the shear strength of mine backfill bodies includes:

[0007] The critical state recognition module collects the real-time data of the shear force and shear displacement of the mine filling body during the anti-shear strength test of the mine filling body, converts it into a curve representation, calculates the gradient mutation points of the curve, marks the key state change positions during the shear process with reference to the gradient mutation points, and obtains the parameter characteristics at the moment of shear failure;

[0008] The loading response prediction module extracts the dynamic change trends of the shear force and shear displacement from the parameter characteristics at the moment of shear failure, predicts the future dynamic development of the shear force and shear displacement after the critical point, and generates a dynamic development sequence in the shear failure stage;

[0009] The loading path optimization module performs segmented analysis on the attenuation law of the shear force and the growth rate of the shear displacement in the dynamic development sequence of the shear failure stage, analyzes the cooperative relationship between the shear force and the shear displacement in each stage, and generates an analysis result of the segmented relationship of the shear loading;

[0010] The loading cooperative control module monitors in real time the change ratios of the shear force and the shear displacement in each segment in the analysis result of the segmented relationship of the shear loading, combines the cooperative relationship between the shear force and the shear displacement, identifies the local stress concentration phenomenon, adjusts the loading distribution of the shear force and the shear displacement according to the identification result, and generates the anti-shear strength test result of the mine filling body.

[0011] As a further solution of the present invention, the step of calculating the gradient mutation points of the curve is specifically as follows:

[0012] Collect the real-time data of the shear force and shear displacement of the mine filling body during the anti-shear strength test of the mine filling body, convert the changes of the shear force and the shear displacement in the real-time data into a curve representation, where the horizontal axis of the curve represents the shear displacement and the vertical axis represents the shear force, and obtain the shear curve of the mine filling body;

[0013] Based on the data in the shear curve of the mine filling body, let the shear force be , and the shear displacement be , calculate the gradient change value of the curve. When reaches an extreme value, determine the corresponding point as the gradient mutation point of the curve.

[0014] As a further solution of the present invention, the step of obtaining the parameter characteristics at the moment of shear failure is specifically as follows:

[0015] According to the gradient mutation points of the curve in the shear curve of the mine filling body, mark the positions of the gradient mutation points, and by analyzing the change trends of the shear force before and after the marked points, identify the transition of the mine filling body from the shear bearing capacity to the structural instability, and obtain the critical state transition position;

[0016] Based on the critical state transition position, extract the correlation data of shear force and shear displacement at the moment of shear failure, and combine the changing trend near the failure point to integrate parameters to generate the parameter characteristics at the moment of shear failure.

[0017] As a further solution of the present invention, the steps for obtaining the dynamic development sequence of the shear failure stage are specifically as follows:

[0018] Extract the dynamic changing trend of shear force and shear displacement from the parameter characteristics at the moment of shear failure, and use the formula: ;

[0019] Calculate the shear force at the next moment , with the unit of Newton ( ), to obtain the dynamic change prediction result;

[0020] wherein, represents the shear force measured in the shear test at the current moment , is the adjustment coefficient, is the sliding window length, is the sliding average value of the shear force, represents the shear force value at the moment ;

[0021] Based on the dynamic change prediction result, analyze the attenuation law of the shear force and the growth rate of the shear displacement in the shear failure stage, and extract the change characteristics of the shear force and the shear displacement point by point to generate the dynamic development sequence of the shear failure stage.

[0022] As a further solution of the present invention, the steps for obtaining the analysis result of the shear loading segmented relationship are specifically as follows:

[0023] Based on the dynamic development sequence of the shear failure stage, by segmentally analyzing the attenuation law of the shear force and the growth rate of the shear displacement, extract the change amplitude of the shear force and the change amount of the shear displacement in each segment to generate the change characteristics of the shear force and the shear displacement within the segment;

[0024] Based on the change characteristics of the shear force and the shear displacement within the segment, use the formula: ;

[0025] Calculate the total score representing the collaborative optimization of the shear force and the shear displacement in the corresponding segment to obtain the analysis result of the shear loading segmented relationship;

[0026] wherein, represents the number of the segment in the dynamic development sequence of the shear failure stage, represents the total number of segments in the dynamic development sequence of the shear failure stage, represents the The weight of the segment in the overall collaborative optimization objective Indicates the Score of the collaborative relationship between shear force and shear displacement within the segment

[0027] As a further solution of the present invention, the steps of identifying the local stress concentration phenomenon are specifically as follows:

[0028] Real-time monitor the changes in shear force and shear displacement of each segment in the shear loading segmentation relationship analysis result, and use the formula: ;

[0029] Calculate the change ratio of shear force and shear displacement of the segment ;

[0030] Among them, is the change amplitude of the shear force of the segment, indicating the total change amount of the shear force within the current segment, is the change amount of the shear displacement of the segment;

[0031] Based on the change ratio, combined with the collaborative relationship between shear force and shear displacement, identify the local stress concentration phenomenon of each segment to obtain the stress concentration analysis result

[0032] As a further solution of the present invention, the steps of obtaining the test result of the shear strength of the mine filling body are specifically as follows:

[0033] Based on the stress concentration analysis result, extract the shear force change and shear displacement change data within each segment, adjust the shear force loading rate and shear displacement change trend of the abnormal segment by analyzing the deviation range of the segment change ratio, and perform dynamic monitoring and adjustment to generate the overall mechanical response analysis result;

[0034] Based on the overall mechanical response analysis result, extract the key parameter data of the maximum shear force, maximum shear displacement and failure time, compare and analyze them with the reference data, and integrate the loading adjustment record and the change ratio to generate the test result of the shear strength of the mine filling body

[0035] The automatic test method for the shear strength of the mine filling body is executed based on the above automatic test system for the shear strength of the mine filling body, and includes the following steps:

[0036] S1: Based on the real-time data of shear force and shear displacement during the test of the shear strength of the mine filling body, convert it into a curve representation, calculate the gradient mutation point of the curve, and mark the key state change positions during the shear process with reference to the gradient mutation point to generate the parameter characteristics at the shear failure moment;

[0037] S2: Based on the parameter characteristics at the moment of shear failure, analyze the dynamic change trends of shear force and shear displacement, predict the future dynamic development of shear force and shear displacement after the critical point, and generate a dynamic development sequence for the shear failure stage;

[0038] S3: Based on the dynamic development sequence of the shear failure stage, analyze the attenuation law of shear force and the growth rate of shear displacement, analyze the cooperative relationship between shear force and shear displacement at each stage, and generate an analysis result of the sectional relationship of shear loading;

[0039] S4: Based on the analysis result of the sectional relationship of shear loading, monitor the change ratio of shear force and shear displacement in each section in real time, combine the cooperative relationship between shear force and shear displacement, identify the phenomenon of local stress concentration, and adjust the loading distribution of shear force and shear displacement to generate a test result of the shear resistance strength of the mine filling body.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] In the present invention, by collecting the dynamic data of shear force and shear displacement in real time and converting them into shear curves, accurately calculating the gradient mutation points in the curves, marking the key state changes in the shear process, and identifying the critical state where the material changes from shear bearing capacity to structural instability, it provides a key basis for the analysis of shear strength. Combining the prediction of the dynamic change trends of shear force and shear displacement, the scheme predicts the short-term trend of the change of shear force by the moving average method, further analyzes the mechanical laws in the shear failure stage, extracts key mechanical characteristics and generates a dynamic development sequence. In the sectional optimization, the scheme extracts the characteristics of the attenuation of shear force and the growth of shear displacement section by section, deeply analyzes the cooperative relationship between the two, identifies the stress concentration phenomenon in each section of the test, avoids local imbalance problems, and flexibly adjusts the proportional distribution in the test process. Finally, by extracting key parameters such as the maximum shear force, maximum shear displacement and failure time, and comparing them with the reference data, the mechanical response is comprehensively quantified, improving the accuracy and efficiency of the test and providing data support for the shear strength test of materials. Description of the Drawings

[0042] Figure 1 is the system flow chart of the present invention;

[0043] Figure 2 is the flow chart for calculating the gradient mutation points of the curve of the present invention;

[0044] Figure 3 is the flow chart for obtaining the parameter characteristics at the moment of shear failure of the present invention;

[0045] Figure 4 is the flow chart for obtaining the dynamic development sequence of the shear failure stage of the present invention;

[0046] Figure 5 Flow chart for obtaining the analysis result of the shear loading segmentation relationship in the present invention;

[0047] Figure 6 Flow chart for identifying the local stress concentration phenomenon in the present invention;

[0048] Figure 7 Flow chart for obtaining the test result of the shear strength of the mine filling body in the present invention. Detailed implementation manners

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Please refer to Figure 1 , the present invention provides a technical solution: The automatic test system for the shear strength of the mine filling body includes:

[0051] A critical state recognition module, which collects the real-time data of the shear force and shear displacement of the mine filling body during the shear strength test of the mine filling body and converts it into a curve representation, calculates the gradient mutation points of the curve, and marks the key state change positions during the shear process with reference to the gradient mutation points to obtain the parameter characteristics at the moment of shear failure;

[0052] A loading response prediction module, which extracts the dynamic change trends of the shear force and shear displacement from the parameter characteristics at the moment of shear failure, predicts the future dynamic development of the shear force and shear displacement after the critical point, and generates a dynamic development sequence in the shear failure stage;

[0053] A loading path optimization module, which performs segmented analysis on the attenuation law of the shear force and the growth rate of the shear displacement in the dynamic development sequence in the shear failure stage, analyzes the coordination relationship between the shear force and the shear displacement in each stage, and generates an analysis result of the shear loading segmentation relationship;

[0054] A loading coordination control module, which real-time monitors the change ratios of the shear force and the shear displacement in each segment in the analysis result of the shear loading segmentation relationship, combines the coordination relationship between the shear force and the shear displacement, identifies the local stress concentration phenomenon, and adjusts the loading distribution of the shear force and the shear displacement according to the identification result to generate the test result of the shear strength of the mine filling body;

[0055] The parameter characteristics at the moment of shear failure specifically include the position where the shear bearing capacity decreases, the starting position of structural instability, and the key change points of shear force and shear displacement; the dynamic development sequence in the shear failure stage includes the shear force attenuation trend sequence, the shear displacement growth trend sequence, and the predicted values of shear parameter changes after the critical point; the analysis results of the shear loading segmented relationship specifically include the segmented change characteristics of shear force, the segmented growth law of shear displacement, and the segmented coordination relationship between shear force and shear displacement; the test results of the shear strength of mine backfill include shear strength test data, shear stage response characteristics, and overall mechanical parameters in the shear failure stage.

[0056] Please refer to Figure 2 , the steps for calculating the gradient mutation point of the curve are specifically as follows:

[0057] Collect the real-time data of the shear force and shear displacement of the mine backfill during the shear strength test of the mine backfill, and convert the changes in shear force and shear displacement in the real-time data into a curve representation. Among them, the horizontal axis of the curve represents the shear displacement, and the vertical axis represents the shear force, to obtain the shear curve of the mine backfill;

[0058] Collect the real-time data of the shear force and shear displacement of the mine backfill during the shear strength test of the mine backfill. Use data acquisition software such as LabVIEW to input the signals collected by the shear force sensor and displacement sensor into the computer. Through the software, process and visualize the collected real-time data, organize the numerical signals of shear force and shear displacement into corresponding time series data, use the time series data to construct the corresponding relationship between shear force and shear displacement, and generate a smooth curve through data interpolation method. Set the horizontal axis of the generated curve as the shear displacement and the vertical axis as the shear force to complete the curve conversion of the changes in shear force and shear displacement.

[0059] Based on the data in the shear curve of the mine backfill, let the shear force be , and the shear displacement be , and use the formula: ;

[0060] Calculate the gradient change value of the curve , when reaches an extreme value, determine the corresponding point as the gradient mutation point of the curve;

[0061] Among them, represents the shear force received by the mine backfill during the test, with the unit of Newton ( ), which is collected in real time by a shear tester. The shear tester uses a force sensor to monitor the shear force corresponding to each unit displacement during the test and records it as discrete point data to form a data set of the relationship between shear force and shear displacement, represents the displacement in the shear direction during the test, with the unit of millimeter ( ) It is collected in real time by a displacement sensor. During the experiment, the shear displacement is directly recorded by the sensor, and the displacement values at each loading step are recorded. is the gradient change value, and it also represents the absolute value of the second derivative of the shear force with respect to displacement, which is used to measure the severity of the change in the shear force, with the unit of newton per square millimeter ( ) It is obtained by performing numerical calculations on the sequence of acquisition points of the shear force , and the calculation formula is: , is the interval displacement difference of the slope change amplitude, and the formula is: , is the th discrete data point of the shear force, which represents the shear force corresponding to the th sampling displacement point during the shear test, with the unit of newton ( ). It is directly collected by a shear tester. For example, if the th displacement point is , and its corresponding shear force value is , is the th discrete data point of the shear force, which represents the shear force corresponding to the th sampling displacement point during the shear test, with the unit of newton ( ). It is directly collected by a shear tester. For example, if the th displacement point is , and its corresponding shear force value is , is the th discrete data point of the shear force, which represents the shear force corresponding to the th sampling displacement point during the shear test, with the unit of newton ( ). It is directly collected by a shear tester. For example, if the th displacement point is , and its corresponding shear force value is , is the th discrete data point of the shear displacement, which represents the th sampling displacement point during the shear test, with the unit of millimeter ( ). It is directly collected by a shear tester. For example, the th displacement point may be , is the th discrete data point of the shear displacement, which represents the th sampling displacement point during the shear test, with the unit of millimeter ( ). It is directly collected by a shear tester. For example, the A displacement point may be , is the th discrete data point of shear displacement, representing the th sampling displacement point during the shear test, in millimeters ( ), directly collected by a shear tester. For example, the th displacement point may be .

[0062] If the following shear force and shear displacement data points (unit: ) are collected through experiments:

[0063] ;

[0064] Calculate the gradient change value: According to the formula:

[0065] ;

[0066] ;

[0067] In the sequence of calculated gradient change values, is the maximum value. Therefore, is the gradient mutation point.

[0068] Please refer to Figure 3 . The steps for obtaining the parameter characteristics at the moment of shear failure are specifically as follows:

[0069] Based on the gradient mutation point of the curve in the shear curve of the mine filling body, mark the position of the gradient mutation point. By analyzing the change trend of the shear force before and after the marked point, identify the transition of the mine filling body from shear bearing capacity to structural instability, and obtain the critical state transition position;

[0070] First, extract the discrete points of shear force and shear displacement from the shear test data. By calculating the gradient change value of the shear force varying with the shear displacement, determine the position of the gradient mutation point, and mark the gradient mutation point as the key state change position; Using the gradient mutation point as a reference point, record the shear force value and the shear displacement value , then analyze the changing trends of shear force and shear displacement before and after the marked point. By observing the stable growth of shear force before the marked point and the rapid decline trend after the marked point, identify the transition of the mine filling body from shear bearing capacity to structural instability. For example, in a certain experiment, when the shear displacement increased from 0 mm to 10 mm, the changing trend of the collected shear force showed a staged increase from 0 N to 500 N. However, when the shear displacement reached the gradient mutation point corresponding to 10 mm, the shear force rapidly dropped to 300 N, and the shear displacement continued to increase. Thus, it was judged that the rapid decline of the shear force was an indication of the structural instability of the mine filling body, and the gradient mutation point was the position of the critical state transition.

[0071] Based on the position of the critical state transition, extract the correlation data of shear force and shear displacement at the moment of shear failure, and combine the changing trends near the failure point to integrate parameters to generate the parameter characteristics at the moment of shear failure.

[0072] Combined with the aforementioned identified gradient mutation point and its corresponding shear force value , analyze the characteristics at the moment of shear failure, extract the changing trends of shear force and shear displacement near the moment of failure from the collected shear test data, and record the change amplitude of the shear force before and after the gradient mutation point. For example, the shear force drops from 500 N to 300 N, corresponding to the mutation of the shear displacement increasing from 10 mm to 12 mm. By statistically analyzing the gradient change value and the shear force value at the key state change position, integrate these data into a set of parameter characteristics at the moment of shear failure, and further calibrate the critical parameters of the mine filling body in the shear failure stage to quantify the shear strength characteristics.

[0073] Please refer to Figure 4 , the specific steps for obtaining the dynamic development sequence in the shear failure stage are as follows:

[0074] Extract the dynamic changing trends of shear force and shear displacement from the parameter characteristics at the moment of shear failure, and use the formula: ;

[0075] Calculate the shear force at the next moment , with the unit of Newton ( ), to obtain the dynamic change prediction result;

[0076] Among them, represents the shear force measured in the shear test at the current moment , with the unit of Newton ( ), which is directly collected by the force sensor in the shear tester. is the adjustment coefficient, representing the weight ratio of the shear force at the current moment and the historical average shear force to the future predicted value, with a value range of [0, 1]. The specific value is set according to the volatility of the shear force data. By analyzing the fluctuation range of the historical shear force data, a smaller value (such as 0.4) is taken when it is relatively stable, and a larger value (such as 0.7) is taken when the volatility is stronger. is the sliding window length, representing the number of historical data points used for the moving average calculation, without a unit. The specific value is set through the shear force sampling frequency and the number of experimental historical data points. For example, if the sampling is once per second and the data of the last 5 seconds is analyzed, then , is the moving average of the shear force, representing the sum of the to shear force data, without a unit, calculated from the historical data in the sliding window. represents the time index within the sliding window, with a value range of to to , obtained by traversing the historical data points. represents the shear force value at time , in Newtons ([[]] ), directly collected by the shear tester. is the weight of the historical average shear force, representing the influence ratio of the moving average in the prediction formula, with a value range of [0, 1], determined by complementing the value of .

[0077] If in the shear test, the shear force data collected by the shear tester is: , the sliding window length is , the adjustment coefficient is , the moving average calculation formula is: , calculate the moving average:

[0078] The sliding window length is , the current time , then take and of the shear force data, substitute into the formula: ;

[0079] Predict the shear force value at time :

[0080] According to the prediction formula: ;

[0081] Substitute the known parameters:

[0082] The shear force at the current time is ; Sliding average ; Adjustment coefficient . Then ;

[0083] The results show that the predicted shear force at the calculated time is .

[0084] Based on the prediction results of dynamic changes, analyze the attenuation law of shear force and the growth rate of shear displacement in the shear failure stage, extract the change characteristics of shear force and shear displacement point by point, and generate a dynamic development sequence in the shear failure stage;

[0085] Extract the shear force and shear displacement values corresponding to each moment from the predicted shear force data and shear displacement data, analyze the change trend of the shear force point by point, record the attenuation value of the shear force by calculating the change amplitude of the shear force between adjacent moments, and at the same time combine the shear displacement data to calculate the growth value of the shear displacement at the corresponding moment, and record the change relationship between the shear force and the shear displacement; in the analysis process, compare the decreasing amplitude of the shear force in time and the increasing speed of the shear displacement according to the order of the data points, extract the attenuation rate of the shear force and the growth rate of the shear displacement, and combine the numerical values of the attenuation rate and the growth rate to form the dynamic change characteristics of the shear failure stage; for example, in a certain test, the predicted shear force decreases from 174 N to 150 N, and the shear displacement increases from 10 mm to 12 mm. By recording the shear force attenuation amplitude of 24 N and the shear displacement increase of 2 mm point by point, and further analyzing the characteristics of the shear failure stage in combination with the time span of the two changes, finally integrate the attenuation law of the shear force and the growth rate of the shear displacement to generate a dynamic development sequence in the shear failure stage.

[0086] Please refer to Figure 5 , and the specific steps for obtaining the analysis results of the shear loading segmented relationship are as follows:

[0087] Based on the dynamic development sequence in the shear failure stage, by segmentally analyzing the attenuation law of the shear force and the growth rate of the shear displacement, extract the change amplitude of the shear force and the change amount of the shear displacement segment by segment, and generate the change characteristics of the shear force and the shear displacement within the segment;

[0088] Analyze the attenuation law of shear force and the growth rate of shear displacement in the dynamic development sequence of the shear failure stage by segments. By dividing the dynamic development sequence of the shear failure stage into multiple segments in chronological order, extract the change characteristics of shear force and shear displacement within each segment. First, according to the collected shear force and shear displacement data, divide the entire sequence into several segments with equal time intervals, record the shear force values and shear displacement values at the starting and ending points of each segment, and then calculate the attenuation amplitude of shear force and the growth amplitude of shear displacement within each segment, and extract their numerical characteristics. In specific operations, use the change amount of shear force and the change amount of shear displacement within each segment as characteristic descriptions, and analyze the distribution of these characteristics in the time dimension segment by segment. For example, in a test sequence, divide the data where the shear force decreases from 180 N to 150 N and the shear displacement increases from 10 mm to 12 mm into a segment, record the change amplitude of shear force within this segment as -30 N, and the change amount of shear displacement as +2 mm. By sequentially extracting these segment characteristics, form a set of segment change characteristics of shear force and shear displacement in the entire failure stage, laying a foundation for subsequent analysis of the correlation between each segment.

[0089] Based on the change characteristics of shear force and shear displacement within the segment, use the formula: ;

[0090] Calculate the total score representing the collaborative optimization of shear force and shear displacement in each segment , and obtain the analysis result of the shear loading segment relationship;

[0091] Among them, represents the number of segments in the dynamic development sequence of the shear failure stage, and the value range is , which is determined by the result of segment analysis and is the unique number of each segment obtained by segment-by-segment division, represents the total number of segments in the dynamic development sequence of the shear failure stage, without unit, and is determined by the segment analysis method, such as the number of segments obtained by dividing according to time intervals or change characteristics, represents the weight of the th segment in the overall collaborative optimization goal, which is determined by factors such as the importance of the segment and the segment length. For example, segments with a larger change amplitude of shear force are given higher weights, represents the score of the collaborative relationship between shear force and shear displacement within the th segment, without unit, and is calculated from the matching degree of the change amplitude of shear force and the growth amplitude of shear displacement within the segment. For example, the correlation between the two changes is quantified by the normalization method.

[0092] If the number of segments in the dynamic development sequence of the shear failure stage, the weight coefficients and collaborative relationship scores of each segment are as follows: Segment 1: , ; Segment 2: , .

[0093] Calculate the overall synergy score : ;

[0094] Substitute the known parameters: ;

[0095] Calculation result represents the optimized overall synergy score, indicating that there is a certain degree of matching relationship between the shear force and shear displacement among different segments; by comparing the weights and scores of different segments, the characteristics of each segment can be further optimized to improve the overall synergy effect.

[0096] Please refer to Figure 6 , the steps to identify local stress concentration phenomenon are specifically as follows:

[0097] Real-time monitor the changes of shear force and shear displacement of each segment in the analysis result of shear loading segment relationship, and use the formula: ;

[0098] Calculate the change ratio of shear force and shear displacement of the th segment ;

[0099] Among them, is the change amplitude of the shear force of the th segment, representing the total change amount of the shear force within the current segment, with the unit of Newton ( ), obtained from the difference between the shear force data at the starting point and the ending point of the segment: , and respectively represent the shear force values at the starting point and the ending point of the segment. The shear force data is collected by the force sensor of the shear tester, such as the real-time shear force value recorded in the experiment. is the shear displacement change amount of the th segment, representing the total change amount of the shear displacement within the current segment, with the unit of millimeter ( ), obtained from the difference between the shear displacement data at the starting point and the ending point of the segment: , and respectively represent the shear displacement values at the starting point and the ending point of the segment. The shear displacement data is collected by the displacement sensor of the shear tester, such as the real-time displacement data recorded in the experiment.

[0100] If in the shear test, the starting shear force of segment is , the ending shear force ; the starting shear displacement , the termination shear displacement .

[0101] Shear force change: ;

[0102] Shear displacement change: ;

[0103] Calculate the change ratio: ;

[0104] Calculation result Indicates the negative growth ratio of the shear force varying with the shear displacement within the segment .

[0105] Based on the change ratio, combined with the synergistic relationship between the shear force and the shear displacement, identify the local stress concentration phenomenon in each segment to obtain the stress concentration analysis result;

[0106] By comprehensively analyzing the synergistic scores and the change ratio of each segment, screen out the segments that may have local stress concentration. In specific implementation, first perform a distribution statistics on the value of each segment, and compare it with the reference change ratio range. For example, in the experiment, the reference ratio range is set to . If the change ratio of a certain segment exceeds this range, for example , it is determined that there is a significant change anomaly in this segment; then, combined with the synergistic score , further evaluate the overall synergy of the abnormal segment. For example, if a certain segment and is lower than the scores of other segments , it is further confirmed that the synergy between the shear force and the shear displacement of this segment is poor; finally, by analyzing the characteristics of the abnormal segment, for example, combined with the shear force change amplitude and the shear displacement change amplitude of specific numerical values, for example, the shear force change amplitude is and the shear displacement change amplitude is , thus comprehensively judging that this segment may be a local stress concentration area.

[0107] Please refer to Figure 7 , the specific steps for obtaining the shear strength test results of the mine backfill are as follows:

[0108] Based on the stress concentration analysis result, extract the shear force change and shear displacement change data within each segment. By analyzing the deviation range of the segment change ratio, adjust the shear force loading rate and the shear displacement change trend of the abnormal segment, and perform dynamic monitoring and adjustment to generate the overall mechanical response analysis result;

[0109] First, extract the shear force change and shear displacement change within each segment, and calculate the change ratio deviation of each segment. For example, set the loading balance range as , when the change ratio of a certain segment exceeds this range, mark this segment as abnormal loading; through the distribution analysis of the shear force and shear displacement data of the abnormally loaded segment, for example, record the shear force change of a certain segment as , the shear displacement change as , the change ratio , and judge the degree of loading imbalance of this segment according to the deviation amplitude; then, combined with the real-time loading record of this segment, reduce the shear force loading rate of the abnormal segment through the dynamic loading adjustment method. For example, change the shear force loading rate from to , and at the same time monitor the change trend of the shear displacement to ensure the adjusted loading balance range; finally, through the comparative analysis of the shear force and shear displacement change ratios before and after the adjustment of each segment, for example, compare that the change ratio after adjustment returns to , confirm that the loading balance is improved after adjustment, and form the overall mechanical response analysis result, including the dynamic change trend of shear force and shear displacement, the adjustment record of the loaded unbalanced segment, and the change ratios before and after the adjustment.

[0110] Based on the overall mechanical response analysis result, extract the key parameter data of the maximum shear force, maximum shear displacement and failure time, conduct a comparative analysis with the reference data, and integrate the loading adjustment record and the change ratio to generate the test result of the shear strength of the mine filling body;

[0111] Extract the key parameter data, including the maximum shear force value, maximum shear displacement value, loading adjustment coefficient and failure time, etc. For example, record that the maximum shear force in the experiment is , the maximum shear displacement is , the loading adjustment coefficient is , the final failure time is ; conduct a comparative analysis of the extracted key parameters with the historical reference data. For example, the maximum shear force of the historical reference data is , and the maximum shear force of the current experiment is higher than the reference value by , so it is judged that the current mine filling body has higher shear resistance; then integrate the adjustment records of the shear force and shear displacement of each segment in the experiment record into the test report. For example, record that the change ratio after adjustment of each segment returns to to range, and the loading balance is significantly improved; finally, organize the above key parameters, adjustment records and the comparison results of the reference data into the test report of the shear strength of the mine filling body, as the basis for subsequent evaluation and engineering application, and form a complete test result including various shear resistance characteristic parameters.

[0112] An automated test method for the shear strength of mine backfill, which is executed based on the above-mentioned automated test system for the shear strength of mine backfill, includes the following steps:

[0113] S1: Based on the real-time data of shear force and shear displacement during the shear strength test of mine backfill, convert it into a curve representation, calculate the gradient mutation points of the curve, mark the key state change positions during the shear process with reference to the gradient mutation points, and generate the parameter characteristics at the moment of shear failure;

[0114] S2: Based on the parameter characteristics at the moment of shear failure, analyze the dynamic change trends of shear force and shear displacement, predict the future dynamic development of shear force and shear displacement after the critical point, and generate a dynamic development sequence for the shear failure stage;

[0115] S3: Based on the dynamic development sequence of the shear failure stage, analyze the attenuation law of shear force and the growth rate of shear displacement, and analyze the cooperative relationship between shear force and shear displacement at each stage, and generate an analysis result of the sectional relationship of shear loading;

[0116] S4: Based on the analysis result of the sectional relationship of shear loading, monitor the change ratio of shear force and shear displacement in each section in real time, combine the cooperative relationship between shear force and shear displacement, identify local stress concentration phenomena, and adjust the loading distribution of shear force and shear displacement to generate the test result of the shear strength of mine backfill.

[0117] The above is only a preferred embodiment of the present invention, and it does not limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. The automatic testing system for shear strength of mine filling body is characterized by: include: The critical state identification module collects the real-time data of shear force and shear displacement of the mine filling body during the shear strength test of the mine filling body and converts it into a curve representation, calculates the gradient mutation point of the curve, and marks the key state change position in the shear process with reference to the gradient mutation point to obtain the parameter characteristics of the shear failure moment; A loading response prediction module is used to extract the dynamic change trend of shear force and shear displacement from the parameter characteristics at the shear failure moment, predict the future dynamic development of shear force and shear displacement after the critical point, and generate a dynamic development sequence of the shear failure stage; The loading path optimization module performs segmented analysis on the attenuation law of the shear force and the growth rate of the shear displacement in the dynamic development sequence of the shear failure stage, analyzes the synergistic relationship between the shear force and the shear displacement in each stage, and generates segmented shear loading relationship analysis results; The loading coordination control module monitors the change ratio of shear force and shear displacement of each segment in the shear loading segment relationship analysis result in real time, identifies the local stress concentration phenomenon based on the coordinated relationship between shear force and shear displacement, adjusts the loading distribution of shear force and shear displacement according to the identification result, and generates the shear strength test result of the mine filling body.

2. The automatic testing system for shear strength of mine filling according to claim 1 is characterized in that: The step of calculating the gradient mutation point of the curve is specifically as follows: Collect the real-time data of shear force and shear displacement of the mine filling body during the shear strength test of the mine filling body, convert the shear force and shear displacement changes in the real-time data into a curve representation, wherein the horizontal axis of the curve represents the shear displacement and the vertical axis represents the shear force, and obtain the shear curve diagram of the mine filling body; Based on the data in the shear curve of the mine filling body, the shear force is , the shear displacement is , calculate the gradient change value of the curve ,when When the extreme value is reached, the corresponding point is determined to be the gradient mutation point of the curve.

3. The automatic testing system for shear strength of mine filling according to claim 2 is characterized in that: The steps for obtaining the parameter characteristics of the shear failure moment are specifically as follows: According to the gradient mutation point of the curve in the shear curve diagram of the mine filling body, the position of the gradient mutation point is marked, and by analyzing the change trend of the shear force before and after the marked point, the transition of the mine filling body from shear bearing capacity to structural instability is identified, and the critical state transition position is obtained; Based on the critical state transition position, the shear force and shear displacement correlation data at the shear failure moment are extracted, and combined with the change trend near the failure point, the parameters are integrated to generate the parameter characteristics of the shear failure moment.

4. The automatic testing system for shear strength of mine filling according to claim 3 is characterized in that: The steps for obtaining the dynamic development sequence of the shear failure stage are specifically as follows: The dynamic change trend of shear force and shear displacement is extracted from the parameter characteristics at the shear failure moment, using the formula: ； Calculate the next moment Shear force , in Newtons ( ), and obtain the dynamic change prediction result; in, Indicates the current time The shear force measured in the shear test, is the adjustment factor, is the sliding window length, is the sliding mean of the shear force, Indicates time Shear force value; Based on the dynamic change prediction results, the attenuation law of shear force and the growth rate of shear displacement in the shear failure stage are analyzed, the change characteristics of shear force and shear displacement are extracted point by point, and the dynamic development sequence of the shear failure stage is generated.

5. The automatic testing system for shear strength of mine filling according to claim 4 is characterized in that: The steps for obtaining the shear loading segment relationship analysis results are specifically as follows: Based on the dynamic development sequence of the shear failure stage, the shear force attenuation law and the shear displacement growth rate are analyzed segment by segment, and the shear force change amplitude and shear displacement change amount are extracted segment by segment to generate the shear force and shear displacement change characteristics within the segment. Based on the variation characteristics of shear force and shear displacement within the segment, the formula is adopted: ； Calculation represents the total score of shear force and shear displacement after the corresponding segmented collaborative optimization , and obtain the analysis results of the shear loading segment relationship; in, Indicates the number of the segment in the dynamic development sequence of the shear failure stage, represents the total number of segments in the dynamic development sequence of the shear failure stage, Indicates The weight of the segment in the overall collaborative optimization objective, Indicates Score for the synergy between shear force and shear displacement within a segment.

6. The automatic testing system for shear strength of mine filling according to claim 5 is characterized in that: The steps of identifying the local stress concentration phenomenon are specifically as follows: The changes of shear force and shear displacement of each segment in the shear loading segment relationship analysis results are monitored in real time, using the formula: ； Calculate the The ratio of shear force to shear displacement ; in, It is The segment shear force change amplitude indicates the total change of shear force in the current segment. It is Segment shear displacement variation; Based on the change ratio and in combination with the synergistic relationship between shear force and shear displacement, the local stress concentration phenomenon of each segment is identified to obtain the stress concentration analysis result.

7. The automatic testing system for shear strength of mine filling according to claim 6 is characterized in that: The steps for obtaining the shear strength test results of the mine filling body are specifically as follows: Based on the stress concentration analysis results, the shear force change and shear displacement change data in each segment are extracted, and the shear force loading rate and shear displacement change trend of the abnormal segment are adjusted by analyzing the deviation range of the segment change ratio, and dynamic monitoring and adjustment are performed to generate the overall mechanical response analysis results; Based on the overall mechanical response analysis results, key parameter data of maximum shear force, maximum shear displacement and failure time are extracted, compared with benchmark data, and the loading adjustment records and change ratios are integrated to generate the shear strength test results of the mine filling body.

8. An automated test method for shear strength of mine fillings, characterized in that: The automatic testing system for shear strength of mine filling body according to any one of claims 1 to 7 comprises the following steps: S1: Based on the real-time data of shear force and shear displacement during the shear strength test of mine filling, the data are converted into curve representation, the gradient mutation points of the curve are calculated, the key state change positions in the shear process are marked with reference to the gradient mutation points, and the parameter characteristics of the shear failure moment are generated; S2: Based on the parameter characteristics at the moment of shear failure, the dynamic change trend of shear force and shear displacement is analyzed, the future dynamic development of shear force and shear displacement after the critical point is predicted, and a dynamic development sequence of the shear failure stage is generated; S3: Based on the dynamic development sequence of the shear failure stage, the attenuation law of the shear force and the growth rate of the shear displacement are analyzed, the synergistic relationship between the shear force and the shear displacement in each stage is analyzed, and the segmented relationship analysis results of the shear loading are generated; S4: Based on the analysis results of the shear loading segment relationship, the change ratio of shear force and shear displacement of each segment is monitored in real time. Combined with the synergistic relationship between shear force and shear displacement, the local stress concentration phenomenon is identified, and the loading distribution of shear force and shear displacement is adjusted to generate the shear strength test results of the mine filling body.

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