A method and device for monitoring stress in a steel cable during a tensioning construction process

Abstract

The present application relates to the technical field of stress monitoring, in particular to a kind of stress monitoring method and device for steel cable tensioning construction process.In the process of steel cable tensioning, the stress time series data of each monitoring position is obtained;Since stress data has delay, the local neighborhood of each monitoring position is determined, the difference characteristics of stress time series data between monitoring positions in neighborhood are analyzed, the stress change delay index is determined in combination with position distribution, and the stress transmission delay characteristics are accurately described;At the same time, the local influence is considered, the neighborhood influence index of each monitoring position at the current time is determined based on the numerical difference of stress change delay index and the change of stress time series data in neighborhood, and the degree of mutual influence is quantified;Considering the current stress state and local influence, the next time predicted stress value is determined according to the numerical characteristics of stress time series data of each monitoring position at the current time and neighborhood influence index, and then the monitoring of steel cable tensioning is realized, and the monitoring accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stress monitoring, in particular to a stress monitoring method and device for steel cable tensioning construction process. BACKGROUND

[0002] In the construction process of large civil engineering structures such as large bridges, high-rise buildings, large venues, etc., steel cable tensioning construction is one of the key links. As an important load-bearing component of the structure, the stress state of the steel cable is directly related to the safety and stability of the entire structure. During the steel cable tensioning construction process, accurate monitoring of the stress changes of the steel cable is of great significance to ensure construction quality and prevent structural safety accidents.

[0003] In the steel cable tensioning construction process, in order to ensure the accuracy of the applied stress, prevent the stress from being too low to achieve the desired effect, or the stress from being too high to exceed the limit that the steel cable can withstand, the stress of the steel cable needs to be monitored. The existing technology often uses fiber grating detection method, which monitors the stress of each point by burying optical fiber sensors inside the concrete structure; but a fixed threshold interval is usually set, and if the stress of the steel cable exceeds the threshold interval, it is considered to be at risk of damage; but in actual application scenarios, there is mutual influence between the points inside the steel cable, and the obtained stress data has a certain delay, such as ignoring this mutual influence, it cannot well predict the subsequent changes of the stress of each point, and it is easy to make mistakes in judgment, which leads to the stress exceeding the limit that the steel cable can withstand and causing irreversible damage to the steel cable, and in severe cases, even causing economic losses and a decrease in construction efficiency. SUMMARY

[0004] In order to solve the technical problem that in actual application scenarios, there is mutual influence between the points inside the steel cable, and the obtained stress data has a certain delay, such as ignoring this mutual influence, it cannot well predict the subsequent changes of the stress of each point, and it is easy to make mistakes in judgment, which leads to the stress exceeding the limit that the steel cable can withstand and causing irreversible damage to the steel cable, and in severe cases, even causing economic losses and a decrease in construction efficiency, the purpose of the present application is to provide a stress monitoring method and device for steel cable tensioning construction process, the technical scheme adopted is as follows:

[0005] A stress monitoring method for steel cable tensioning construction process, comprising:

[0006] During the steel cable tensioning process, acquiring stress time series data at each monitoring position;

[0007] Determining the local neighborhood corresponding to each monitoring position; within the local neighborhood corresponding to each monitoring position, analyzing the change difference characteristics of the stress time series data between the monitoring positions, and combining the position distribution of the monitoring positions, determining the stress change delay index of each monitoring position at each moment;

[0008] characteristics of the numerical differences between the stress change delay indicators of the respective monitoring positions, and in combination with the change conditions of the stress time series data of the monitoring positions in the local neighborhood, determine the neighborhood influence indicator corresponding to each monitoring position at the current time;

[0009] At the current time, according to the numerical characteristics of the stress time series data of each monitoring position and the neighborhood influence indicator of each monitoring position, determine the predicted stress value of each monitoring position at the next time; based on the predicted stress value of each monitoring position at the next time, monitor the tensioning condition of the steel cable.

[0010] Further, the method for obtaining the stress change delay indicator comprises:

[0011] Optionally, one monitoring position is taken as the to-be-measured position;

[0012] In the local neighborhood corresponding to the to-be-measured position, compare the change characteristics of the stress values of the monitoring positions at adjacent times to determine the first stress change delay factor corresponding to the to-be-measured position at each time;

[0013] According to the relative position relationship between the to-be-measured position and the tensioning end of the steel cable, determine the second stress change delay factor corresponding to the to-be-measured position;

[0014] The product of the first stress change delay factor corresponding to the to-be-measured position at each time and the second stress change delay factor after normalization is taken as the stress change delay indicator corresponding to the to-be-measured position at each time.

[0015] Further, the method for obtaining the first stress change delay factor comprises:

[0016] In the local neighborhood corresponding to the to-be-measured position, for any one monitoring position, in the stress time series data of the monitoring position, the difference value between each time and the adjacent previous time after normalization is taken as the stress increase factor corresponding to the monitoring position at each time;

[0017] In the local neighborhood corresponding to the to-be-measured position, all monitoring positions are arranged in descending order according to the distance between the monitoring positions and the tensioning end of the steel cable to obtain a sorting sequence, a difference sequence of the stress increase factors of the monitoring positions is calculated based on the sorting sequence, and in the difference sequence, the difference value between the next data value and the previous data value after normalization is taken as the first stress change delay factor of the to-be-measured position at each time.

[0018] Further, the method for obtaining the second stress change delay factor comprises:

[0019] Obtain the total length of the steel cable, and obtain the distance between the to-be-measured position and the tensioning end of the steel cable as a distance factor;

[0020] The ratio of the distance factor to the total length of the steel cable is taken as a second stress change delay factor corresponding to the to-be-measured position.

[0021] Further, the method for obtaining the neighborhood influence index comprises:

[0022] At the current moment, the numerical difference characteristics among the stress change delay indexes of all the monitoring positions are analyzed to determine the relative influence degree of each monitoring position;

[0023] At each moment, the change of the stress values of the monitoring positions in the local neighborhood corresponding to each monitoring position is analyzed to determine the relative stress change degree of each monitoring position at the current moment;

[0024] At the current moment, the product of the relative influence degree and the relative stress change degree corresponding to each monitoring position is normalized to obtain the neighborhood influence index corresponding to each monitoring position at the current moment.

[0025] Further, the method for obtaining the relative influence degree comprises:

[0026] At the current moment, the maximum value of the stress change delay indexes at all the monitoring positions is taken as a comparison value, and for any one monitoring position, the ratio of the difference between the comparison value and the stress change delay index at the monitoring position to the comparison value is taken as the relative influence degree of the monitoring position at the current moment.

[0027] Further, the method for obtaining the relative stress change degree comprises:

[0028] In the stress time series data at each monitoring position, the ratio of the difference between the stress values at each moment and the adjacent previous moment to the time interval is taken as the stress relative change rate at each moment;

[0029] For any one monitoring position, for any one moment, the average stress change factor corresponding to the monitoring position at the moment is taken as the average stress change factor of all the monitoring positions at the moment in the local neighborhood corresponding to the monitoring position;

[0030] The difference between the average stress change factor of the monitoring position at the current moment and the average stress change factor at the adjacent previous moment is normalized to obtain the relative stress change degree of the monitoring position at the current moment.

[0031] Further, the method for obtaining the predicted stress value comprises:

[0032] In the stress time series data at each monitoring position, the difference between the maximum stress value and the minimum stress value is taken as the stress change amplitude;

[0033] a sum of the neighborhood influence index corresponding to each monitoring position at the current time and a preset constant as an adjustment degree value;

[0034] a product of the adjustment degree value corresponding to each monitoring position at the current time and the stress change amplitude as a stress prediction adjustment amount of each monitoring position at the next time;

[0035] a sum of the stress value of each monitoring position at the current time and the corresponding stress prediction adjustment amount as a predicted stress value of each monitoring position at the next time.

[0036] Further, the monitoring of the tensioning condition of the steel cable based on the predicted stress value of each monitoring position at the next time comprises:

[0037] taking the average of the predicted stress values of all monitoring positions at the next time as a to-be-measured stress index;

[0038] when the to-be-measured stress index corresponding to the steel cable is greater than a preset maximum stress value, it is judged that there is a risk of damage;

[0039] otherwise, calculating the difference between the to-be-measured stress index and a preset minimum stress value as a stress deviation value, taking the difference between the preset maximum stress value and the preset minimum stress threshold value as a variation amplitude value, and taking the ratio of the stress deviation value and the variation amplitude value as a tensioning index corresponding to the steel cable, if the tensioning index is less than or equal to a preset first tensioning threshold value, it is judged that tensioning needs to be continued, if the tensioning index is greater than the preset first tensioning threshold value and less than or equal to a preset second tensioning threshold value, it is judged that the tensioning is up to standard and needs to be stopped, and if the tensioning index is greater than the preset second tensioning threshold value, it is judged that there is a risk of damage.

[0040] A stress monitoring device for a steel cable tensioning construction process comprises a processor and a memory, the memory stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to realize the steps of a stress monitoring method for a steel cable tensioning construction process.

[0041] The present application has the following beneficial effects:

[0042] The stress time series data at each monitoring position is obtained during the steel cable tensioning process to provide a data basis for subsequent accurate analysis and prediction. Stress is essentially the elastic internal force generated by the interaction per unit area inside the object when it is deformed by external force. In actual scenarios, there is interaction inside the object, so the stress data will have a certain delay. Therefore, the local neighborhood corresponding to each monitoring position is determined, and the change difference characteristics of the stress time series data between monitoring positions are analyzed in the local neighborhood. The stress change delay index of each monitoring position at each time is determined in combination with the position distribution. This process considers the mechanical transmission mechanism of the steel cable and accurately depicts the transmission delay characteristics of stress between different positions. Further, there is external tension and interaction between adjacent positions inside the steel cable, so the local influence is considered: based on the numerical difference characteristics between the stress change delay indexes of each monitoring position, and in combination with the change of the stress time series data of the monitoring positions in the local neighborhood, the neighborhood influence index corresponding to each monitoring position at the current time is determined to quantify the mutual influence degree between the monitoring positions in the local neighborhood, which provides a basis for subsequent accurate prediction of stress change. In view of the fact that the current stress state and local mutual influence are comprehensively considered, the stress change trend of each position of the steel cable can be predicted in advance, so at the current time, the predicted stress value of each monitoring position at the next time is determined according to the numerical characteristics of the stress time series data of each monitoring position and the neighborhood influence index. Finally, the tensioning of the steel cable is monitored based on the predicted stress value of each monitoring position at the next time, which can realize the advance prediction and dynamic monitoring of the stress change of the steel cable, and greatly improve the accuracy of the monitoring result. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, a brief introduction will be given to the drawings needed in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings.

[0044] Figure 1 A method flowchart of a stress monitoring method for a steel cable tensioning construction process provided by an embodiment of the present application;

[0045] Figure 2 A schematic diagram of a steel cable provided by an embodiment of the present application;

[0046] Figure 3 A schematic diagram of an implementation scenario provided by an embodiment of the present application;

[0047] Figure 4A method flow chart of a stress change delay index acquisition method provided by an embodiment of the present application;

[0048] Figure 5 A method flow chart of a neighborhood influence index acquisition method provided by an embodiment of the present application;

[0049] Figure 6 A device structure schematic diagram of a stress detection device for a steel cable tensioning construction process provided by an embodiment of the present application;

[0050] The figure mark: 1-concrete member, 2-reserved hole, 3-prestressed steel cable, 4-fiber grating sensor. DETAILED DESCRIPTION

[0051] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the following describes in detail the specific embodiments, structures, features and effects of a stress monitoring method and device for a steel cable tensioning construction process according to the present application, with reference to the accompanying drawings and preferred embodiments. Different “one embodiment” or “another embodiment” in the following description do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0053] The following specifically describes the specific scheme of a stress monitoring method and device for a steel cable tensioning construction process provided by the present application, with reference to the accompanying drawings.

[0054] Please refer to Figure 1 which shows a method flow chart of a stress monitoring method for a steel cable tensioning construction process provided by an embodiment of the present application. The method includes the following steps:

[0055] Step S1: In the steel cable tensioning process, acquire stress time series data at each monitoring position.

[0056] Prestress is a technology to improve the service performance of a structure, which applies a compressive stress to the structure during construction, so that the compressive stress can offset part of the tensile stress caused by the load during the service period of the structure, avoiding the destruction of the structure. It is commonly used in concrete structures, and the use of prestressed concrete structures makes the resulting building less prone to cracking, improves its stiffness and durability, and is widely used in the field of buildings such as bridges. Among the prestressed concrete projects, prestressed steel strands are often used to provide stress. The prestressed steel strand is a twisted steel cable composed of several high-strength steel wires (such as Figure 2As shown, the post-tensioned steel strand is simply referred to as steel cable, in the process of tensioning construction of steel cable, through the jack, anchorage and clamping piece and other tools to be lengthened and fixed, so that it has a certain prestress, combined with subsequent casting engineering to get prestressed concrete member.

[0057] And in the process of steel cable tensioning construction, in order to guarantee the stress applied accurately, to prevent the stress too high beyond the limit that steel cable can bear, it is necessary to monitor the stress size. In the embodiment of the application, the optical fiber grating detection method is adopted, by embedding the optical fiber sensor into the concrete structure and distributing it evenly along the concrete member, setting multiple monitoring positions (such as Figure 3 As shown, it shows the scene implementation schematic diagram, including concrete member 1, the reserved hole 2 in the concrete member 1 is used to place the prestressed steel cable 3, and the concrete member 1 inside is evenly set with several monitoring positions along the length of the concrete member for deploying optical fiber grating sensor 4), so as to obtain the stress time series data at each monitoring position in the process of steel cable tensioning (the optical fiber grating detection method is based on the strain-wavelength characteristics of optical fiber grating, when the steel cable is deformed under stress, the period of optical fiber grating will change, so as to cause the wavelength of reflected light to shift, that is, the stress size of steel cable can be calculated by monitoring the wavelength shift).

[0058] It should be noted that in the embodiment of the application, the length of the stress time series data can be set to one minute of history from the current time, and the data acquisition frequency can be set to one second; the length and acquisition frequency can be adjusted according to the implementation scene, which is not limited here.

[0059] Step S2: determine the local neighborhood corresponding to each monitoring position; in the local neighborhood corresponding to each monitoring position, analyze the change difference characteristics of the stress time series data between the monitoring positions, and combine the position distribution of the monitoring positions to determine the stress change delay index of each monitoring position at each time.

[0060] Stress is essentially the elastic internal force between the unit area of the object caused by the deformation of the external force. In the ideal state, the uniform and unbending steel cable has no other external force except the tension force, and the stress size is equal at any cross-sectional position. However, in the real situation, the steel cable is a continuous structure, and the stress propagation in it has obvious spatial correlation. Generally, one end of the steel cable is fixed, and the other end is tensioned. During the tensioning process, the area close to the tensioning end is more likely to be affected by the tensioning force and deformed than the area close to the fixed end. Subsequently, the deformation of the area close to the tensioning end affects the area close to the fixed end, and the continuous mutual influence causes the internal stress of the entire steel cable to change, so there is a certain delay in the stress change of each point. Therefore, the local neighborhood corresponding to each monitoring position is first determined, and in the embodiments of the present application, each monitoring position and the two adjacent monitoring positions before and after it constitute the local neighborhood of each monitoring position (therefore, the monitoring positions located at both ends do not have a local neighborhood, and they are not analyzed in the subsequent process). Then, the change difference characteristics of the stress time series data in the local neighborhood are analyzed, which can fully utilize the spatial correlation and more accurately capture the dynamic process of stress propagation. At the same time, in combination with the position distribution of the monitoring positions, the stress change delay index can be more reasonably determined, reflecting the spatial and temporal characteristics of stress propagation.

[0061] Preferably, the method for obtaining the stress change delay index in an embodiment of the present application comprises:

[0062] Please refer to Figure 4 , which shows the method flowchart of the method for obtaining the stress change delay index in an embodiment of the present application. The method comprises the following steps:

[0063] Step S201: Optionally, a monitoring position is selected as a to-be-measured position. In the local neighborhood corresponding to the to-be-measured position, the change characteristics of the stress values of the monitoring positions at adjacent time points are compared, and the first stress change delay factor corresponding to the to-be-measured position at each time point is determined.

[0064] In the local neighborhood corresponding to the to-be-measured position, for any monitoring position, the difference between the stress value at each time point and the adjacent previous time point is calculated in the stress time series data of the monitoring position. If the difference is positive, it means that the stress value at each time point of the monitoring position increases with time. If the difference is negative, it means that the stress value at each time point of the monitoring position decreases with time. The normalized value of the difference is used as the stress increase factor corresponding to the monitoring position at each time point. Since the difference value can be positive or negative, the normalization method used here can adopt the function.

[0065] In the local neighborhood corresponding to the to-be-tested position, all monitoring positions are arranged in descending order according to the distance from the steel cable tensioning end, that is, the monitoring position farther away from the tensioning end has a smaller sequence number value, so as to obtain a sorting sequence. Then, a difference sequence of the stress increase factors of the monitoring positions is calculated based on the sorting sequence. The data value in the difference sequence reflects the deviation characteristics of the stress increase factors of the adjacent two monitoring positions on the steel cable. If the value is positive and larger, it means that the stress increase amplitude of the monitoring position closer to the tensioning end is larger than that of the monitoring position farther away from the tensioning end. Therefore, the difference value of the two can reflect the degree to which the stress increase amplitude of the monitoring position closer to the tensioning end is higher than that of the monitoring position farther away from the tensioning end. Therefore, in the difference sequence, the difference value between the next data value and the previous data value is calculated. The larger the difference value is, the relatively higher the stress change amplitude of the monitoring position closer to the tensioning end is in the local neighborhood corresponding to the to-be-tested position. Therefore, the stress change delay property in the local neighborhood can be considered to be relatively larger. Therefore, the value of the difference value after normalization is taken as the first stress change delay factor of the to-be-tested position at each moment.

[0066] Step S202: determining a second stress change delay factor corresponding to the to-be-tested position according to the relative position relationship between the to-be-tested position and the steel cable tensioning end.

[0067] The stress of the steel cable propagates from the tensioning end. The farther away from the tensioning end, the longer the time required for stress propagation, and the relatively lagging stress change. Therefore, the delay characteristics of the stress change can also be quantified from the position distribution characteristics of the monitoring positions on the steel cable.

[0068] First, the total length of the steel cable is obtained. Then, the distance between the to-be-tested position and the steel cable tensioning end is obtained as a distance factor. The larger the distance factor is, the longer the time required for stress propagation. Therefore, the ratio of the distance factor to the total length of the steel cable is taken as the second stress change delay factor corresponding to the to-be-tested position. The larger the second stress change delay factor is, the slower the influence of the tensioning force on the to-be-tested position is, that is, the more significant the stress change delay will be.

[0069] Step S203: fusing the first stress change delay factor and the second stress change delay factor corresponding to the to-be-tested position at each moment, so as to quantify the stress change delay index corresponding to the to-be-tested position at each moment.

[0070] Based on the analysis in steps S201 and S202, the first stress change delay factor reflects the stress change delay situation of the to-be-tested position in the local neighborhood, the second stress change delay factor reflects the stress change delay situation of the to-be-tested position in the entire length direction of the steel cable, and at each time, the first stress change delay factor and the second stress change delay factor of the to-be-tested position are positively correlated with the stress change delay of the to-be-tested position. Therefore, in this embodiment, the value of the product of the first stress change delay factor and the second stress change delay factor of the to-be-tested position at each time after normalization is taken as the stress change delay index of the to-be-tested position at each time. Based on the foregoing logic, the greater the stress change delay index, the more significant the stress change delay of the to-be-tested position, and thus the timeliness of the stress change should be appropriately improved during subsequent stress prediction to avoid misjudgment. The normalization is a technical means familiar to those skilled in the art, and the selection of the normalization function can be linear normalization or standard normalization, and the specific normalization method is not limited herein.

[0071] Step S3: Based on the numerical difference characteristics between the stress change delay indexes of the monitoring positions, and in combination with the change of the stress time sequence data of the monitoring positions in the local neighborhood, the neighborhood influence index corresponding to each monitoring position at the current time is determined.

[0072] The stress change delay index obtained in step S2 mainly reflects the relative delay of stress change of a single position at different times, but in actual engineering, the stress state of the steel cable is a complex dynamic system, and the stress changes of the positions are correlated with each other. For example, two monitoring positions close to each other, but due to the interaction between them, the stress change of one position can have a significant impact on the other position. Therefore, in this step, the numerical difference characteristics between the stress change delay indexes of the monitoring positions can be analyzed, and in combination with the change of the stress time sequence data of the monitoring positions in the local neighborhood, the neighborhood influence index corresponding to each monitoring position at the current time is determined.

[0073] Preferably, the method for obtaining the neighborhood influence index in an embodiment of the present application comprises:

[0074] Please refer to Figure 5 which shows the method flowchart of the method for obtaining the neighborhood influence index in an embodiment of the present application, and the method comprises the following steps:

[0075] Step S301: At the current time, the numerical difference characteristics between the stress change delay indexes of all monitoring positions are analyzed to determine the relative influence degree of each monitoring position.

[0076] The maximum value of the stress change delay index at all monitoring positions at the current time is taken as a comparison value, which can provide a unified reference standard for all monitoring positions, so that the relative influence degree can be calculated based on the same benchmark regardless of the numerical size of the stress change delay index of different monitoring positions, so that the relative delay situation of different positions is comparable.

[0077] Then, for any monitoring position, the difference between the comparison value and the stress change delay index at the monitoring position is calculated, and the ratio of the difference to the comparison value is taken as the relative influence degree of the monitoring position at the current time. The smaller the stress change delay index of the monitoring position, the greater the difference, and the lower the relative delay situation of the stress change of the monitoring position. At this time, the relative influence degree is greater, which means that it is more likely to have a larger stress change subsequently and thus is more affected by the stress of the adjacent monitoring position. It should be noted that the stress change delay index in the embodiment of the present application is not simultaneously 0 at the same time, that is, the comparison value is not 0. If this special situation occurs, the relative influence degree is directly set to 0.

[0078] Step S302: At each time, the change of the stress value of the monitoring position in the local neighborhood corresponding to each monitoring position is analyzed to determine the relative stress change degree of each monitoring position at the current time.

[0079] In the stress time series data at each monitoring position, the ratio of the difference between the stress value at each time and the adjacent previous time to the time interval is taken as the stress relative change rate at each time. The greater the positive stress relative change rate, the more obvious the stress value at the time.

[0080] For any monitoring position, for any time, the average of the stress relative change rates of all monitoring positions in the local neighborhood corresponding to the monitoring position at the time is taken as the average stress change factor corresponding to the monitoring position at the time. The average stress change factor considers the stress growth of multiple monitoring positions in the local neighborhood and reflects the average stress change level of the local neighborhood where the monitoring position is located, which helps to grasp the stress change trend of the local area as a whole. The greater the average stress change factor, the more significant the overall stress growth in the local neighborhood where the monitoring position is located.

[0081] At this point, for any monitoring position, the average stress change factor corresponding to the monitoring position at each time can be obtained, and finally the difference between the average stress change factor of the monitoring position at the current time and the average stress change factor of the adjacent previous time is calculated. The difference represents the rising amplitude of the average stress change of the local neighborhood region where the monitoring position is located at the current time. The greater the positive difference value is, the more likely the subsequent average stress change of the local neighborhood region where the monitoring position is located will be higher, and the greater the influence degree of the stress at the front and rear monitoring positions. Therefore, the value of the difference value after normalization is used as the corresponding stress change degree of the monitoring position at the current time. Based on the foregoing analysis, the greater the relative stress change degree is, the more significant the stress change of the monitoring position at the current time is in the growth trend, and the greater the influence degree of the stress of the adjacent monitoring position is. Since the difference value here can be positive or negative, the normalization method can adopt function.

[0082] Step S303: At the current time, the relative influence degree and the relative stress change degree of each monitoring position are integrated to determine the neighborhood influence index corresponding to each monitoring position at the current time.

[0083] Based on the analysis in steps S301 and S302, the greater the relative influence degree of each monitoring position at the current time is, the more likely it is to have a larger stress change subsequently, and thus the greater the influence degree of the stress of the adjacent monitoring position is. At the same time, the greater the relative stress change degree is, the more significant the stress change of the monitoring position at the current time is in the growth trend, and the greater the influence degree of the stress of the adjacent monitoring position is. Therefore, the product of the relative influence degree and the relative stress change degree corresponding to each monitoring position after normalization is used as the neighborhood influence index corresponding to each monitoring position at the current time. Based on the foregoing analysis, the greater the neighborhood influence index is, the higher the influence degree of the stress of the adjacent monitoring position is, and the more likely it is to have a higher amplitude of stress change in the subsequent process. The normalization is a technical means familiar to those skilled in the art, and the selection of the normalization function can be linear normalization or standard normalization, and the specific normalization method is not limited here.

[0084] Step S4: At the current time, the predicted stress value of each monitoring position at the next time is determined according to the numerical characteristics of the stress time series data of each monitoring position and the neighborhood influence index of each monitoring position; and the tensioning condition of the steel cable is monitored based on the predicted stress value of each monitoring position at the next time.

[0085] The steel cable structure is a continuous whole, and the stresses between the monitoring positions interact with each other, the neighborhood influence index quantifies the influence degree of each monitoring position on other monitoring positions in the local neighborhood and the possibility of higher stress change in the future, so the stress value of each monitoring position at the next moment can be predicted by using the index and the numerical characteristics of the stress time series data of each monitoring position, thereby obtaining the predicted stress value, and finally the stress of the steel cable during the tensioning construction process can be monitored based on the predicted stress value of each monitoring position at the next moment, to realize the early warning of the possible risks of the steel cable tensioning.

[0086] Preferably, in an embodiment of the present application, the method for obtaining the predicted stress value comprises:

[0087] Firstly, in the stress time series data at each monitoring position, the difference between the maximum stress value and the minimum stress value is taken as the stress change amplitude, which represents the overall range of stress change of the monitoring position and can provide an important reference for the adjustment in subsequent stress prediction.

[0088] Then, the sum of the neighborhood influence index corresponding to each monitoring position at the current moment and a preset constant is taken as the adjustment degree value, the greater the adjustment degree value, the more significant the influence of the stress of other monitoring positions on the monitoring position at the current moment, and there will be a larger stress change amplitude in the future, so the stress value needs to be increased more during subsequent stress value prediction to avoid the risk of being unable to judge in time.

[0089] Next, the product of the adjustment degree value corresponding to each monitoring position at the current moment and the stress change amplitude is taken as the stress prediction adjustment amount of each monitoring position at the next moment, by multiplying the adjustment degree value and the stress change amplitude, the neighborhood influence and the change characteristics of the stress itself can be combined, so that the stress prediction adjustment amount calculated is more in line with the actual stress change trend. When the stress change amplitude of a monitoring position is large and the neighborhood influence index is also large, the stress prediction adjustment amount calculated will also be large, indicating that the stress of the monitoring position at the next moment may have a large growth.

[0090] Finally, the sum of the stress value of each monitoring position at the current moment and the corresponding stress prediction adjustment amount is taken as the predicted stress value of each monitoring position at the next moment.

[0091] It should be noted that, in order to prevent over-adjustment, the preset constant in the embodiment of the present application is set to 1.

[0092] After obtaining the predicted stress value of each monitoring position at the next moment, the tensioning construction process of the steel cable can be monitored according to the index.

[0093] Preferably, in one embodiment of the present application, stress monitoring based on the predicted stress values of each monitoring position at the next moment in time comprises:

[0094] Taking the average of the predicted stress values of all monitoring positions at the next moment in time as the stress index to be measured, the stress index to be measured can more comprehensively represent the stress state of the steel cable as a whole at the next moment in time.

[0095] At this time, when the stress index to be measured corresponding to the steel cable is greater than the preset maximum stress value, it is considered to be out of the normal stress allowable range of the steel cable, so it is directly judged that there is a risk of damage and needs to be warned.

[0096] Otherwise, the difference between the stress index to be measured and the preset minimum stress value can be calculated as a stress deviation value, the difference between the preset maximum stress value and the preset minimum stress threshold value can be calculated as a variation amplitude value, and the ratio of the stress deviation value and the variation amplitude value can be calculated as a tensioning index corresponding to the steel cable. The greater the tensioning index, the greater the overall stress state of the steel cable at the next moment in time, so if the tensioning index is less than or equal to the preset first tensioning threshold value, it is judged that tensioning needs to continue, if the tensioning index is greater than the preset first tensioning threshold value and less than or equal to the preset second tensioning threshold value, it is judged that the tensioning is up to standard and needs to be stopped, and if the tensioning index is greater than the preset second tensioning threshold value, it is judged that there is a risk of damage and needs to be warned in time.

[0097] It should be noted that the preset maximum stress value and the preset minimum stress value can be obtained and set according to the design specification of the steel cable, the material properties, etc. At the same time, according to the experimental conclusion, the preset first tensioning threshold value can be set to 0.25 and the preset second tensioning threshold value can be set to 0.8. The specific values can be adjusted according to the implementation scene, and are not limited herein.

[0098] In summary, by obtaining the stress time series data at each monitoring position during the steel cable tensioning process, a data basis is provided for subsequent accurate analysis and prediction. Stress is essentially the elastic internal force generated by the interaction of unit area inside the object when it is deformed by external force. In actual scenarios, there is interaction inside the object, so the stress data will have a certain delay. Therefore, the local neighborhood corresponding to each monitoring position is determined, and the change difference characteristics of the stress time series data between monitoring positions are analyzed in the local neighborhood. The stress change delay index of each monitoring position at each time is determined in combination with the position distribution. This process considers the mechanical transmission mechanism of the steel cable and accurately depicts the transmission delay characteristics of stress between different positions. Further, there is external tension and interaction between adjacent positions inside the steel cable, so the local influence is considered. Based on the numerical difference characteristics between the stress change delay indexes of each monitoring position, and in combination with the change of the stress time series data of the monitoring positions in the local neighborhood, the neighborhood influence index corresponding to each monitoring position at the current time is determined, which quantifies the mutual influence degree between the monitoring positions in the local neighborhood and provides a basis for subsequent accurate stress change prediction. Since the current stress state and local mutual influence are considered, the stress change trend of each position of the steel cable can be predicted in advance. Therefore, according to the numerical characteristics of the stress time series data of each monitoring position and the neighborhood influence index, the predicted stress value of each monitoring position at the next time is determined. Finally, based on the predicted stress value of each monitoring position at the next time, the tensioning of the steel cable is monitored, which can realize the advance prediction and dynamic monitoring of the stress change of the steel cable, and greatly improve the accuracy of the monitoring result.

[0099] The embodiment of the present application also provides a stress monitoring device for a steel cable tensioning construction process. Figure 6 The device structure schematic diagram of the stress monitoring device for the steel cable tensioning construction process provided by the embodiment of the present application is shown in FIG. 1, which comprises a processor 600, a memory 601, a bus 602 and a communication interface 603, wherein the processor 600, the communication interface 603 and the memory 601 are connected through the bus 602; the memory 601 can contain a high-speed random access memory, the bus 602 can be an ISA bus, a PCI bus or an EISA bus, etc., the processor 600 can be an integrated circuit chip with signal processing capability; the memory 601 stores at least one instruction, at least one program, a code set or an instruction set, which are loaded and executed by the processor to realize the steps in the stress monitoring method for the steel cable tensioning construction process.

[0100] It is to be noted that the sequential order of the above-described embodiments of the present application only for the purpose of description, but not the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0101] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments.

Claims

1. A method for stress monitoring during steel cable tensioning construction, characterized in that, The method includes: During the tensioning of the steel cable, stress time series data at various monitoring locations are acquired; Determine the local neighborhood corresponding to each monitoring location; within the local neighborhood corresponding to each monitoring location, analyze the variation characteristics of stress time series data between monitoring locations, and combine the location distribution of monitoring locations to determine the stress change delay index at each monitoring location at each time point; Based on the numerical differences between stress change delay indices at various monitoring locations, and combined with the changes in stress time series data at monitoring locations within the local neighborhood, the neighborhood influence index corresponding to each monitoring location at the current moment is determined. At the current moment, the predicted stress value of each monitoring location at the next moment is determined based on the numerical characteristics of the stress time series data at each monitoring location and the neighborhood influence index of each monitoring location; the tensioning of the steel cable is monitored based on the predicted stress values ​​of each monitoring location at the next moment. The method for obtaining the stress change delay index includes: Choose any monitoring location as the location to be measured; Within the local neighborhood of the location to be measured, compare the stress value change characteristics between monitoring locations at adjacent times, and determine the first stress change delay factor corresponding to the location to be measured at each time. Based on the relative positional relationship between the test location and the tensioning end of the steel cable, determine the second stress change delay factor corresponding to the test location; The normalized value of the product of the first stress change delay factor and the second stress change delay factor at each time point is used as the stress change delay index at each time point of the test location. The method for obtaining the first stress change retardation factor includes: Within the local neighborhood of the location to be measured, for any monitoring location, the normalized value of the difference between the stress value at each moment and the adjacent previous moment in the stress time series data at that monitoring location is used as the stress increase factor corresponding to that monitoring location at each moment. In the local neighborhood corresponding to the location to be measured, all monitoring locations are arranged in descending order according to their distance from the tensioning end of the steel cable to obtain a sorting sequence. Based on the sorting sequence, the difference sequence of stress increase factors of the monitoring locations is calculated. In the difference sequence, the normalized value of the difference between the next data value and the previous data value is used as the first stress change delay factor of the location to be measured at each time. The method for obtaining the second stress change retardation factor includes: Obtain the total length of the steel cable and use the distance between the location to be measured and the tensioning end of the steel cable as a distance factor; The ratio of the distance factor to the total length of the steel cable is used as the second stress change delay factor corresponding to the location to be measured.

2. The stress monitoring method for steel cable tensioning construction process according to claim 1, characterized in that, The method for obtaining the neighborhood influence index includes: At the current moment, analyze the numerical differences in stress change delay indices at all monitoring locations to determine the relative impact of each monitoring location; At each time point, the stress value changes within the local neighborhood of each monitoring location are analyzed to determine the relative stress change at each monitoring location at the current time. At the current moment, the normalized product of the relative influence degree and the relative stress change degree corresponding to each monitoring location is used as the neighborhood influence index corresponding to each monitoring location at the current moment.

3. The stress monitoring method for steel cable tensioning construction process according to claim 2, characterized in that, The method for obtaining the relative influence includes: At the current moment, the maximum value of the stress change delay index at all monitoring locations is used as the comparison value. For any monitoring location, the difference between the comparison value and the stress change delay index at that monitoring location is calculated, and the ratio of this difference to the comparison value is used as the relative influence of that monitoring location at the current moment.

4. The stress monitoring method for steel cable tensioning construction process according to claim 2, characterized in that, The method for obtaining the relative stress variation includes: In the stress time series data at each monitoring location, the ratio of the difference between the stress value at each moment and the adjacent previous moment to the time interval is obtained as the relative rate of change of stress at each moment; For any monitoring location, for any time, within the local neighborhood corresponding to that monitoring location, the mean of the relative rate of change of stress at all monitoring locations at that time is taken as the average stress change factor corresponding to that monitoring location at that time. The normalized value of the difference between the average stress change factor at the current monitoring location and the average stress change factor at the adjacent previous time is taken as the relative stress change degree at the current monitoring location.

5. The stress monitoring method for steel cable tensioning construction process according to claim 1, characterized in that, The method for obtaining the predicted stress value includes: In the stress time series data at each monitoring location, the difference between the maximum stress value and the minimum stress value is taken as the stress change amplitude; The sum of the neighborhood influence index corresponding to each monitoring location at the current time and the preset constant is used as the adjustment degree value; The product of the adjustment level value and the stress change amplitude at each monitoring location at the current moment is used as the stress prediction adjustment amount for each monitoring location at the next moment. The sum of the stress value at each monitoring location at the current moment and the corresponding stress prediction adjustment is used as the predicted stress value for each monitoring location at the next moment.

6. The stress monitoring method for steel cable tensioning construction process according to claim 1, characterized in that, The monitoring of the cable tension based on the predicted stress values ​​at each monitoring location at the next moment includes: The average of the predicted stress values ​​at all monitoring locations at the next moment is taken as the stress index to be measured. When the stress index to be tested for the steel cable is greater than the preset maximum stress value, it is determined that there is a risk of damage. Otherwise, calculate the difference between the preset minimum stress value and the preset minimum stress threshold as the stress deviation value, and use the difference between the preset maximum stress value and the preset minimum stress threshold as the variation range value. Use the ratio of the stress deviation value and the variation range value as the tension index corresponding to the steel cable. If the tension index is less than or equal to the preset first tension threshold, it is determined that tensioning needs to continue. If the tension index is greater than the preset first tension threshold and less than or equal to the preset second tension threshold, it is determined that the tensioning meets the standard and tensioning needs to be stopped. If the tension index is greater than the preset second tension threshold, it is determined that there is a risk of damage.

7. A stress monitoring device for the steel cable tensioning construction process, characterized in that, It includes a processor and a memory, the memory storing at least one instruction, at least one program, code set or instruction set, the steps of the stress monitoring method for the steel cable tensioning construction process as described in any one of claims 1-6 being implemented when the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor.

Images