Foundation pit supporting offset detection method, system and device applied to geotechnical engineering

Abstract

The present application relates to the technical field of intelligent sensor, in particular to a kind of method, system and equipment for detecting the displacement of foundation pit support applied to geotechnical engineering.The present application first analyzes the dangerous coefficient of each displacement area in the foundation pit support surface to be measured, then evaluates its potential dangerous factor based on the proximity of monitoring point relative to displacement area, then at the current monitoring time, in combination with the historical time series change of stress at monitoring point, the stability of rock and soil is evaluated, the representativeness of each monitoring point to the displacement of foundation pit support surface to be measured is determined, i.e.the attention coefficient, so as to accurately evaluate the overall displacement of foundation pit support surface to be measured in combination with displacement, which ensures the accuracy of the displacement detection of foundation pit support in geotechnical engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent sensor, in particular to a method, system and device for detecting the displacement of foundation pit support applied to geotechnical engineering. BACKGROUND

[0002] The detection of the displacement of foundation pit support in geotechnical engineering helps to ensure the safety and stability of the foundation pit engineering. Through detection items such as horizontal displacement and vertical settlement, abnormal deformation of the support structure can be found in time so as to take appropriate emergency measures. In the actual detection process, engineers will arrange multiple monitoring points to evaluate the overall displacement of the foundation pit support. For example, the average value of the displacement at all monitoring points is calculated, or the monitoring point with the maximum displacement is focused on.

[0003] However, due to the discreteness and unevenness of the geotechnical layer, the detection data at a single monitoring point cannot fully reflect the geological conditions of the foundation pit. Moreover, the sensor has problems such as large error, significant data island effect, insufficient instantaneous interference and spatial continuity. During construction, abnormal local geological conditions randomly appear between the monitoring points arranged in advance (such as the nearest monitoring point being far away), which may cause the data of some monitoring points to be unable to accurately represent the overall displacement. At this time, using the sum or maximum value of the displacement of all monitoring points to reflect the overall displacement of the foundation pit support may result in a large error, thereby affecting the detection effect. SUMMARY

[0004] In order to solve the technical problem of poor detection effect of the displacement of foundation pit support in geotechnical engineering, the purpose of the present application is to provide a method, system and device for detecting the displacement of foundation pit support applied to geotechnical engineering, and the technical solution adopted is as follows:

[0005] The method for detecting the displacement of foundation pit support applied to geotechnical engineering comprises:

[0006] At each monitoring time, the displacement of each monitoring point in the foundation pit support surface to be measured is collected, and all displacement regions in the foundation pit support surface to be measured are determined based on the displacement. The stress value of each monitoring point is collected in real time.

[0007] At each monitoring time, the dangerous coefficient of each displacement region is obtained according to the distribution change of the displacement of all monitoring points in each displacement region and the distribution of the displacement region, and the potential dangerous factor of each monitoring point is obtained according to the displacement of each monitoring point, the dangerous coefficient and position distribution of the displacement region in the preset neighborhood, and the area and dangerous coefficient of each displacement region in the foundation pit support surface to be measured.

[0008] According to fluctuation of the offset amount in a preset historical period at a current monitoring time, the preset historical period is divided into a plurality of offset stable periods, and according to a length of each offset stable period and a change characteristic of the stress value and the offset amount in the offset stable period, a rock-soil stability coefficient of the monitoring point in each offset stable period is obtained.

[0009] At the current monitoring time, according to the potential dangerous factor of each monitoring point and the rock-soil stability coefficient in each offset stable period, and in combination with a time interval between an end time of the offset stable period and the current monitoring time, an attention coefficient of each monitoring point is obtained.

[0010] Based on the attention coefficients of all monitoring points and the offset amount, an overall offset amount of the to-be-tested foundation pit supporting surface is evaluated.

[0011] Further, the offset region obtaining method comprises:

[0012] At each monitoring time, each monitoring point is taken as a pixel point, a corresponding offset amount is taken as a pixel value, and an offset field image corresponding to the to-be-tested foundation pit supporting surface is fitted by interpolation, the offset field image is segmented based on a watershed algorithm, and a region corresponding to each non-catchment basin in the offset field image in the to-be-tested foundation pit supporting surface is taken as an offset region.

[0013] Further, the dangerous coefficient obtaining method comprises:

[0014] In each offset region, a monitoring point corresponding to a maximum offset amount is taken as an offset peak point, an offset turbulence parameter is obtained according to a deviation of the offset amount of each monitoring point on a region boundary of the offset region relative to the maximum offset amount and a distance between each monitoring point on the region boundary and the offset peak point.

[0015] At each monitoring time, any offset region is taken as a target region, a preset number of offset regions closest to the target region are selected as reference regions, and a neighborhood offset set parameter of the target region is obtained according to a distance between each reference region and the target region.

[0016] The offset turbulence parameter and the neighborhood offset set parameter are fused to obtain a dangerous coefficient of the corresponding offset region.

[0017] Further, the potential dangerous factor obtaining method comprises:

[0018] At each monitoring moment, a first offset parameter is obtained according to the centralized features of the offset amounts at all monitoring points, an area proportion of all the offset regions in the to-be-tested foundation pit support surface is taken as a second offset parameter, a third offset parameter is obtained according to the centralized features of the danger coefficients of all the offset regions, and the first offset parameter, the second offset parameter and the third offset parameter are fused to obtain a offset severity coefficient of the to-be-tested foundation pit support surface;

[0019] At each monitoring moment, the offset region closest to each monitoring point is taken as a dangerous influence region of each monitoring point, a distance between each monitoring point and the corresponding dangerous influence region is negatively correlated to obtain a danger weight, and the danger weight is used to weight the danger coefficient of the corresponding dangerous influence region to obtain a danger influence parameter of each monitoring point;

[0020] At each monitoring moment, the danger influence parameter of each monitoring point and the offset amount corresponding to the monitoring point are fused to obtain an initial danger factor of each monitoring point, and the offset severity coefficient of the to-be-tested foundation pit support surface is used to weight the initial danger factor of each monitoring point to obtain a potential danger factor of each monitoring point.

[0021] Further, the method for obtaining the offset stable period comprises:

[0022] At each monitoring point, a time sequence of the offset amount at the monitoring point in a preset historical period is fitted, the time sequence is segmented based on an APCA segmentation algorithm, and each segmented period is taken as an offset stable period.

[0023] Further, the method for obtaining the geotechnical stability coefficient comprises:

[0024] In each offset stable period of each monitoring point, a stress value time sequence is fitted, the stress value time sequence is divided into a first sequence subsegment and a second sequence subsegment by using a minimum stress value; a first stress stability factor is obtained according to the occurrence moment of the maximum stress value in the first sequence subsegment and the downward trend of the stress value after the occurrence moment; and a second stress stability factor is obtained according to the occurrence moment of the maximum stress value in the second sequence subsegment and the upward trend of the stress value before the occurrence moment;

[0025] In each offset stable period of each monitoring point, a stability weight is obtained according to the centralized features of the offset amounts at all monitoring moments, the first stress stability factor and the second stress stability factor are fused, the stability weight is used to weight the fusion result to obtain a first stability parameter, a normalized result of the length of the offset stable period is taken as a second stability parameter, and a negatively correlated normalized result of the change slope of the offset amount at all monitoring moments is taken as a third stability parameter;

[0026] The first stability parameter, the second stability parameter and the third stability parameter are fused to obtain a rock-soil stability coefficient at the monitoring point in each offset stability period.

[0027] Further, the method for obtaining the attention coefficient comprises:

[0028] For each monitoring point, a time interval between an end time of each offset stability period and a current monitoring time is negatively correlated and normalized to obtain a reference weight of each offset stability period, the rock-soil stability coefficients at the monitoring point in the corresponding offset stability period are weighted and summed by using the reference weight, and a negatively correlated and normalized result of the weighted sum is taken as a dangerous offset parameter at the monitoring point; at the current monitoring time, the dangerous offset parameter is weighted by using the potential dangerous factor of each monitoring point, and a weighted result is taken as an attention coefficient for the corresponding monitoring point.

[0029] Further, the method for evaluating the overall offset amount of the to-be-tested foundation pit supporting surface comprises:

[0030] At the current monitoring time, the attention coefficient for each monitoring point is normalized to obtain an attention weight for each monitoring point, wherein a sum of the attention weights for all monitoring points is 1; the offset amount at the corresponding monitoring point is weighted and summed by using the attention weight, and a weighted sum is taken as an overall offset amount of the to-be-tested foundation pit supporting surface.

[0031] The system for detecting the offset amount of the foundation pit supporting surface applied to the geotechnical engineering comprises:

[0032] The data acquisition module: at each monitoring time, the offset amount at each monitoring point in the to-be-tested foundation pit supporting surface is collected, and all offset regions in the to-be-tested foundation pit supporting surface are determined based on the offset amount; the stress value at each monitoring point is collected in real time;

[0033] The monitoring analysis module: at each monitoring time, the dangerous coefficient of each offset region is obtained according to the distribution change of the offset amount at all monitoring points in each offset region and the distribution of the offset region, and the potential dangerous factor of each monitoring point is obtained according to the offset amount at each monitoring point, the dangerous coefficients and position distribution of the offset regions in the preset neighborhood, and the area and dangerous coefficient of each offset region in the to-be-tested foundation pit supporting surface; at each monitoring point, a preset historical period of the offset amount at the current monitoring time is divided into a plurality of offset stability periods according to the fluctuation of the offset amount, the rock-soil stability coefficient at the monitoring point in each offset stability period is obtained according to the length of each offset stability period and the change characteristics of the stress value and the offset amount in the offset stability period; at the current monitoring time, the attention coefficient for each monitoring point is obtained according to the potential dangerous factor of each monitoring point and the rock-soil stability coefficient in each offset stability period, in combination with the time interval between the end time of the offset stability period and the current monitoring time.

[0034] The offset evaluation module: based on the attention coefficient and the offset of all monitoring points, the overall offset of the to-be-tested foundation pit supporting surface is evaluated.

[0035] The device for detecting the offset of the foundation pit supporting surface applied to geotechnical engineering comprises a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the method for detecting the offset of the foundation pit supporting surface applied to geotechnical engineering when executing the computer program.

[0036] The present application has the following beneficial effects:

[0037] The present application considers that in the process of monitoring the offset of the foundation pit supporting surface in the existing geotechnical engineering, the offset evaluation result is prone to large errors due to the influence of geological conditions and monitoring point layout, thereby affecting the detection effect, therefore, the present application firstly collects the offset at each monitoring point at each monitoring moment, and obtains all offset regions in the to-be-tested foundation pit supporting surface, analyzes the dangerous coefficient of each offset region, further evaluates the influence of the offset region on the adjacent monitoring point, and obtains the potential dangerous factor of each monitoring point; then at each monitoring point, the fluctuation of the offset in the preset historical period of the current monitoring moment is determined to determine a plurality of offset stable periods, the length of each offset stable period and the change characteristics of the internal stress value and the offset are further analyzed, and the geotechnical stability coefficient is determined; finally, the attention coefficient of each monitoring point is obtained at the current monitoring moment, the attention coefficient reflects the representativeness of the offset of the to-be-tested foundation pit supporting surface, and finally the overall offset of the to-be-tested foundation pit supporting surface can be evaluated in combination with the offsets of all monitoring points. The present application analyzes and determines the representativeness of each monitoring point to the offset of the to-be-tested foundation pit supporting surface, i.e. the attention coefficient, so as to accurately evaluate the overall offset of the to-be-tested foundation pit supporting surface in combination with the offset, and the accuracy of the detection of the offset of the foundation pit supporting surface in the geotechnical engineering is ensured BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 A flowchart of a method for detecting the offset of the foundation pit supporting surface applied to geotechnical engineering provided by an embodiment of the present application;

[0040] Figure 2 A flowchart of a method for obtaining a potential dangerous factor provided by an embodiment of the present application. Detailed Implementation

[0041] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method, system, and device for detecting foundation pit support offset in geotechnical engineering based on the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0042] 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 this invention pertains.

[0043] The following description, in conjunction with the accompanying drawings, details the specific scheme of the method, system, and equipment for detecting the offset of foundation pit support in geotechnical engineering provided by this invention.

[0044] Please see Figure 1 The diagram illustrates a flowchart of a method for detecting the offset of foundation pit support in geotechnical engineering, provided by an embodiment of the present invention, specifically including:

[0045] Step S1: At each monitoring time, the offset at each monitoring point in the support surface of the foundation pit to be tested is collected, and all offset areas in the support surface of the foundation pit to be tested are determined based on the offset; the stress value at each monitoring point is collected in real time.

[0046] In one embodiment of the present invention, firstly, one foundation pit support area is selected as the foundation pit support surface to be tested in the foundation pit of geotechnical engineering. The analysis and monitoring methods of all foundation pit support areas are the same. Here, only the foundation pit support surface to be tested is used as an example for analysis and description.

[0047] Specifically, the support surface of the foundation pit to be tested is divided into several sub-regions by a grid division method, and the center of each sub-region is used as a monitoring point. Displacement sensors are integrated at each monitoring point to collect horizontal and vertical displacements, and the Euclidean norm of the horizontal and vertical displacements is used as the offset at the monitoring point. At the same time, stress sensors are deployed at each monitoring point to collect stress values ​​in real time. The above are all existing technical means, and the specific process will not be described in detail.

[0048] It should be noted that implementers can customize the grid size and develop other monitoring point layout schemes, but must adhere to the following: densification in key areas, setting up monitoring points in areas where deformation is possible or where local geological conditions are unfavorable; comprehensive coverage, including the four corners of the foundation pit support, every 10-15m along the outer wall or every 2-3 column foundations, with no less than 3 monitoring points on each side.

[0049] It should be noted that, considering that even if a larger stress change occurs in the rock-soil layer, the displacement change at each monitoring point may be relatively small in a short time, the stress sensor collection frequency is set to one per second to help subsequent analysis of stress distribution change trend and evaluation of rock-soil stability; the displacement sensor collection frequency is set to one per day, that is, the interval between adjacent two monitoring moments is 24 hours; the implementer can also adjust it by himself.

[0050] Considering that the rock-soil layer structures in different regions of the to-be-measured foundation pit supporting surface are different, and are also affected by external load or underground water level change, etc., the offset conditions will also be different; therefore, in the embodiment of the present application, all offset regions in the to-be-measured foundation pit supporting surface are preliminarily determined at each monitoring moment; the offset region is preliminarily evaluated based on the offset amount at a single moment, which provides a basis for the important reference value of subsequent evaluation of each monitoring point.

[0051] Preferably, in an embodiment of the present application, considering that the larger and more concentrated the offset amount is, the region is the offset region, therefore, the to-be-measured foundation pit supporting surface can be regarded as a two-dimensional plane image, each monitoring point can be regarded as a pixel point, and the offset amount can be regarded as a corresponding pixel value, so that the region with a higher offset amount can be segmented by means of image segmentation idea; considering that the monitoring points are not distributed throughout the to-be-measured foundation pit supporting surface, which is not conducive to subsequent image analysis and segmentation, therefore, the remaining pixel points need to be supplemented by interpolation fitting, and a complete offset field image corresponding to the to-be-measured foundation pit supporting surface is obtained; considering that the watershed segmentation algorithm is an image segmentation algorithm based on the principle of geographic morphology, the image can be regarded as the ground, and the region with a high pixel value can be regarded as a mountain range, so that the region with a higher offset amount, that is, the offset region, can be segmented, and the region with a lower offset amount, that is, the region without offset or with a smaller offset amount, is the catchment basin region; therefore, the method for obtaining the offset region comprises:

[0052] At each monitoring moment, each monitoring point is regarded as a pixel point, the corresponding offset amount is regarded as a pixel value, and the to-be-measured foundation pit supporting surface corresponding offset field image is interpolated and fitted, the offset field image is segmented based on the watershed algorithm, and the region corresponding to each non-catchment basin in the to-be-measured foundation pit supporting surface in the offset field image is regarded as the offset region.

[0053] As an example, the nearest neighbor interpolation algorithm is used to fit the offset field image; it should be noted that in other examples, the implementer can also use other interpolation algorithms or segmentation algorithms, which are all prior art means as the nearest neighbor interpolation algorithm fitting the offset field image and the watershed algorithm, and will not be described in detail.

[0054] In another embodiment of the present application, it is considered that it is more intuitive to analyze the displacement field of the to-be-tested foundation pit supporting surface in a three-dimensional space, and the displacement can be regarded as the "amount of bulging" of the to-be-tested foundation pit supporting surface in a two-dimensional plane; therefore, at each monitoring time, the displacement of each monitoring point can be taken as elevation data, and the two-dimensional coordinates of each monitoring point in the corresponding two-dimensional plane of the to-be-tested foundation pit supporting surface are combined to obtain the spatial coordinates of each monitoring point, and then the spatial coordinates of all monitoring points are interpolated and fitted to obtain a three-dimensional curved surface model corresponding to the to-be-tested foundation pit supporting surface; then all peak regions in the three-dimensional curved surface model are obtained, and each peak region will correspond to a displacement region; the above are prior art methods and will not be described in detail.

[0055] In step S2, at each monitoring time, the dangerous coefficient of each displacement region is obtained according to the distribution change of the displacement of all monitoring points in each displacement region and the distribution of the displacement region, and the potential danger factor of each monitoring point is obtained according to the displacement of each monitoring point, the dangerous coefficient and position distribution of the displacement region in the preset neighborhood, and the area and dangerous coefficient of each displacement region in the to-be-tested foundation pit supporting surface.

[0056] It is considered that the foundation pit supporting structure will be continuously adjusted during the construction process to a certain extent to recover the displacement or prevent further deterioration, so the displacement danger degree of each displacement region is not completely increased over time; it is also considered that if the displacement bulging degree of each displacement region is greater and the displacement regions around it are more intensive, it means that the displacement danger degree of the displacement region is possibly greater.

[0057] Therefore, in the embodiment of the present application, at each monitoring time, the dangerous coefficient of each displacement region is obtained according to the distribution change of the displacement of all monitoring points in each displacement region and the distribution of the displacement region, and the dangerous coefficient preliminarily reflects the displacement danger degree or local failure possibility of the supporting structure in each displacement region, which prepares for the reference value for subsequent evaluation of adjacent monitoring points.

[0058] Preferably, in an embodiment of the present application, it is considered that the displacement field of the displacement region can be regarded as a bulging mountain peak, if the height difference (displacement difference) between the boundary point and the peak point (the maximum displacement in the region) is greater, and the distance from the boundary point to the peak point is shorter, it means that the route from the boundary point to the peak point is steeper, and the displacement field is more turbulent; it is also considered that when the displacement regions on the to-be-tested foundation pit supporting surface are concentrated, the soil stress will also be concentrated accordingly, which may accelerate the local failure of the supporting structure, and the dangerous possibility of the displacement region is greater; based on this, the method for obtaining the dangerous coefficient includes:

[0059] In each offset region, the maximum offset corresponding to the monitoring point is taken as the offset peak point, the offset turbulence parameter is obtained according to the deviation of the offset corresponding to each monitoring point on the region boundary of the offset region relative to the maximum offset, and the distance between each monitoring point on the region boundary and the offset peak point; in each monitoring moment, any offset region is taken as a target region, a preset number of offset regions closest to the target region are selected as reference regions, the neighborhood offset central parameter of the target region is obtained according to the distance between each reference region and the target region; the offset turbulence parameter and the neighborhood offset central parameter are fused to obtain the danger coefficient of the corresponding offset region.

[0060] As an example, first, the offset peak point in each offset region and the offset of all region boundary points are determined; then the absolute value of the difference is taken as the measure of the deviation, the absolute value of the difference between the offset of each boundary point and the maximum offset corresponding to the offset peak point is calculated, and the Euclidean distance between each boundary point and the offset peak point is calculated; between each boundary point and the offset peak point, the absolute value of the difference is taken as the numerator, and the Euclidean distance is taken as the denominator to obtain the offset turbulence sub-parameter, and finally the offset turbulence sub-parameters between all boundary points and the offset peak point are averaged to obtain the offset turbulence parameter;

[0061] Wherein, the region boundary of the offset region may not be equipped with monitoring points, then for each region boundary point, the offset of the most adjacent monitoring point can be taken as its offset, or the offset of each boundary point can be determined by means of the offset field image fitted in step S1;

[0062] Then, any offset region is taken as a target region, the preset number is set to 4, all reference regions of the target region in the to-be-measured foundation pit supporting surface, i.e. adjacent offset regions, are selected, and the Euclidean distance between each reference region and the target region is calculated. After the Euclidean distance is averaged, the negative correlation mapping is obtained, such as the reciprocal operation, to obtain the neighborhood offset central parameter of the target region; the target region is changed, and the neighborhood offset central parameter of each offset region can be obtained;

[0063] Finally, the offset turbulence parameter and the neighborhood offset central parameter of each offset region are linearly normalized respectively, and then the two normalized results are averaged to obtain the danger coefficient of the corresponding offset region.

[0064] In order to evaluate the reference value of each monitoring point for evaluating the overall offset of the to-be-measured foundation pit supporting surface, the local failure possibility at the monitoring point can be reflected through the monitored offset and the dangerous situation of the adjacent offset region, so as to evaluate the reference value; and considering that the more the offset regions in the to-be-measured foundation pit supporting surface and the greater the corresponding danger coefficient, the greater the offset degree of the entire to-be-measured foundation pit supporting surface, and on this basis, the offset reference value of each monitoring point is also greater;

[0065] Therefore, the embodiment of the present application further obtains a potential dangerous factor of each monitoring point at each monitoring moment according to the offset amount at each monitoring point, the dangerous coefficient and position distribution of the offset region in the preset neighborhood of the offset amount, and the area and dangerous coefficient of each offset region in the to-be-tested foundation pit support surface.

[0066] Preferably, in an embodiment of the present application, the method for obtaining the potential dangerous factor comprises:

[0067] Please refer to Figure 2 which shows a flowchart of a method for obtaining a potential dangerous factor provided by an embodiment of the present application, and specifically comprises:

[0068] Step S201, at each monitoring moment, a first offset parameter is obtained according to the centralized characteristics of the offset amounts at all monitoring points, the area proportion of all offset regions in the to-be-tested foundation pit support surface is taken as a second offset parameter, a third offset parameter is obtained according to the centralized characteristics of the dangerous coefficients of all offset regions, and the first offset parameter, the second offset parameter and the third offset parameter are fused to obtain an offset severity coefficient of the to-be-tested foundation pit support surface.

[0069] It is considered that the larger the offset amounts of all monitoring points are, and the larger the dangerous coefficients and area of all offset regions are, the more serious the overall offset condition of the to-be-tested foundation pit support surface is. Based on this, the offset severity coefficient of the to-be-tested foundation pit support surface is first obtained to prepare for subsequent analysis of the potential dangerous factor of each monitoring point on the basis of the overall offset.

[0070] Among them, as an example, at each monitoring moment, the centralized characteristics are represented by the mean value, and the first offset parameter and the third offset parameter are obtained respectively; then the first offset parameter, the second offset parameter and the third offset parameter are multiplied and fused, and then the product is mapped into the hyperbolic tangent function for normalization to obtain the offset severity coefficient of the to-be-tested foundation pit support surface; in other examples, the implementer can also use other fusion means such as weighted summation, and can also use other normalization means, which will not be described here.

[0071] Step S202, at each monitoring moment, the offset region closest to each monitoring point is taken as the dangerous influence region of each monitoring point, the distance between each monitoring point and the corresponding dangerous influence region is negatively correlated, a dangerous weight is obtained, the dangerous coefficient of the corresponding dangerous influence region is weighted by using the dangerous weight, and a dangerous influence parameter of each monitoring point is obtained.

[0072] The closer the monitoring point is to the offset region and the greater the dangerous coefficient of the offset region, the greater the influence of the dangerous offset region on the monitoring point. Therefore, the dangerous influence parameter of each monitoring point can be evaluated by means of the adjacent offset region, so as to prepare for subsequent evaluation of the potential dangerous factor in combination with the offset amount monitored by the monitoring point.

[0073] As an example, first, the dangerous influence region of each monitoring point is determined, and the Euclidean distance between the monitoring point and the dangerous influence region is calculated. Then, the Euclidean distance is negatively correlated and mapped, such as being inverted, to obtain the dangerous weight, and further to obtain the dangerous influence parameter of each monitoring point.

[0074] It should be noted that when the Euclidean distance is measured, the distance between the monitoring point and the offset peak point corresponding to the maximum offset amount in the dangerous influence region is calculated. The implementer can also use other negative correlation mapping methods, such as mapping the Euclidean distance to the exponential function exp(-x) with the natural constant e as the base, to avoid the meaningless inverse when the Euclidean distance is 0.

[0075] Step S203, at each monitoring time, the dangerous influence parameter and the corresponding offset amount of each monitoring point are fused to obtain the initial dangerous factor of each monitoring point. The offset severity coefficient of the to-be-tested foundation pit supporting surface is used to weight the initial dangerous factor of each monitoring point to obtain the potential dangerous factor of each monitoring point.

[0076] As an example, at each monitoring time, the dangerous influence parameter and the offset amount of each monitoring point are multiplied and combined to obtain the initial dangerous factor, and then multiplied and combined with the offset severity coefficient of the to-be-tested foundation pit supporting surface to obtain the potential dangerous factor of each monitoring point.

[0077] Step S3, at each monitoring point, according to the fluctuation of the offset amount in the preset historical period of the current monitoring time, the preset historical period is divided into a plurality of offset stable periods, and according to the length of each offset stable period and the change characteristics of the stress value and the offset amount in the offset stable period, the rock-soil stability coefficient of the monitoring point in each offset stable period is obtained.

[0078] It is considered that the offset is caused when the stress reaches the bearing limit of the soil body and the supporting structure. The above only analyzes the offset amount and does not consider the stress change. That is, when the foundation pit supporting offset at each monitoring point is adjusted by construction, the offset amount is adjusted back or reduced and tends to be stable, and if the stress of the soil body and the supporting structure is still large, only the bearing limit is not exceeded, but subsequent small interference will break the stable state. The rock-soil stability at the monitoring point is poor, and the possibility of local failure and dangerous offset is greater. Therefore, the degree of attention to the monitoring point should be greater.

[0079] Therefore, the embodiment of the present application firstly divides the preset historical period into a plurality of offset stable periods according to the fluctuation of the offset amount in the preset historical period at the current monitoring time; wherein each offset stable period refers to a period in which the stress of the foundation pit support is redistributed and tends to be stable after being adjusted by construction, and the offset amount at the monitoring point is similar or changes little in the period; further, the actual stability of the rock and soil at the monitoring point is evaluated by combining the length of each offset stable period and the change characteristics of the stress value and the offset amount in the offset stable period, so as to determine the rock and soil stability coefficient and prepare for subsequent evaluation.

[0080] In an embodiment of the present application, a preset number of historical monitoring times, such as 10, are obtained in reverse along the time sequence from the current monitoring time as the starting point, and a preset historical period is constructed; the implementer can also adjust the preset number according to actual needs.

[0081] Preferably, in an embodiment of the present application, considering that the APCA segmentation algorithm can segment the time sequence similar data into a segment, the method for obtaining the offset stable period comprises:

[0082] At each monitoring point, the time sequence of the offset amount at the monitoring point in the preset historical period is fitted, and the time sequence is segmented based on the APCA segmentation algorithm, and each segment corresponding to the period is taken as an offset stable period.

[0083] It should be noted that fitting the time sequence and segmenting based on the APCA segmentation algorithm are both known technologies and will not be described in detail.

[0084] Considering that the offset stable period can be regarded as a later stage (i.e. the stage after construction adjustment) in which the stress is redistributed and tends to be stable due to the change of the rock and soil layer of the last foundation pit support at the monitoring point, and a former stage (i.e. the stage before the offset amount changes greatly) in which the stress is redistributed due to the change of the rock and soil layer of the next foundation pit support, the combination and splicing period of the two stages; the smaller and more stable the stress change is, the better the stability of the rock and soil layer in the change stage of the adjacent two foundation pit supports is;

[0085] Further, considering that the amplitude level and change trend of the offset amount at the monitoring point in the offset stable period can also help to evaluate the stability of the rock and soil, the larger the offset amount is and the upward trend is, the more unstable it is; at the same time, the shorter the offset stable period is, the faster the offset changes at the monitoring point, and the more unstable it is;

[0086] Based on this, in a preferred embodiment of the present application, the method for obtaining the rock and soil stability coefficient comprises:

[0087] In each offset stable period of each monitoring point, a stress value time sequence is fitted, the stress value time sequence is divided into a first sequence sub-section and a second sequence sub-section by using a minimum stress value; a first stress stability factor is obtained according to an occurrence time of a maximum stress value in the first sequence sub-section and a descending trend of stress values after the occurrence time; a second stress stability factor is obtained according to an occurrence time of a maximum stress value in the second sequence sub-section and an ascending trend of stress values before the occurrence time;

[0088] In each offset stable period of each monitoring point, a stable weight is obtained according to a centralized feature of offset amounts at all monitoring times, a first stress stability factor and a second stress stability factor are fused, a stable weight is used to weight a fusion result, a first stable parameter is obtained, a normalized result of a length of the offset stable period is taken as a second stable parameter, and a negative correlation normalized result of a change slope of the offset amounts at all monitoring times is taken as a third stable parameter;

[0089] The first stable parameter, the second stable parameter and the third stable parameter are fused to obtain a rock-soil stability coefficient of the monitoring point in each offset stable period.

[0090] As an example, in each offset stable period of each monitoring point, first, a stress value time sequence is fitted, and the stress value time sequence is divided into a first sequence sub-section and a second sequence sub-section by using a minimum stress value in the time sequence as a segmentation point (if there are multiple minimum stress values, the earliest occurrence is taken); the first sequence sub-section corresponds to a stress sub-sequence in a later stage in the above logic, and the second sequence sub-section corresponds to a stress sub-sequence in an earlier stage in the above logic;

[0091] In the first sequence sub-section, a maximum stress value (if there are multiple maximum stress values, the last occurrence is taken) is taken, the maximum stress value represents that an influence of stress redistribution caused by a change of a rock-soil layer of a foundation pit support ends at this time, the earlier the occurrence time of the maximum stress value is, and the more obvious the descending trend of stress values after the maximum stress value is, the more stable the stress is in the stage corresponding to the first sequence sub-section; a time interval between the occurrence time of the maximum stress value and a time corresponding to a first stress value in the first sequence sub-section is negatively correlated, for example, an inverse is taken to adjust the logic, the larger the inverse is, the earlier the influence of stress redistribution ends, then a descending slope of stress is calculated based on two points in a time period from the maximum stress value to a last stress value in the first sequence sub-section; the descending slope of stress is multiplied by the inverse of the time interval and combined, and is mapped into a hyperbolic tangent function for normalization to obtain a first stress stability factor;

[0092] Similarly, in the second sequence sub-section, the maximum stress value is taken (if there are multiple maximum stress values, the earliest appearing one is taken), the earlier the maximum stress value appears, the earlier the stress redistribution caused by the change of the next foundation pit support rock-soil layer appears, and the more obvious the growth trend of the stress value before the maximum stress value, the more likely the subsequent stress limit of the rock-soil layer will be broken and deviated; then the time interval between the occurrence time of the maximum stress value and the time corresponding to the first stress value in the second sequence sub-section is calculated, and then the growth slope of the stress is calculated based on the two-point formula in the time interval from the maximum stress value to the first stress value in the second sequence sub-section; the growth slope is multiplied by the time interval to obtain a negative correlation mapping such as taking the reciprocal to adjust the logic, and the reciprocal is mapped into a hyperbolic tangent function for normalization to obtain a second stress stability factor; the larger the time interval and the smaller the growth slope, the later the stress redistribution and the slower the stress growth, and the more stable the rock-soil;

[0093] Then in each displacement stable period of each monitoring point, the mean value of the displacement at all monitoring times is negatively correlated mapped such as taking the reciprocal to adjust the logic to obtain a stable weight, and the first stress stability factor and the second stress stability factor are averaged to obtain a first stable parameter, the stable weight is multiplied by the sum of the first stable parameter and the second stable parameter to obtain a second stable parameter, the change slope of the displacement in the displacement stable period is calculated based on the two-point formula, and the change slope is mapped into a function 1-norm(x) as an independent variable x for negative correlation normalization to obtain a third stable parameter; wherein norm() is a linear normalization function.

[0094] Finally, the first stable parameter and the third stable parameter are averaged and merged, and then the second stable parameter is used as a weight to provide a side reference, and then the second stable parameter is used to weight the averaging and merging result to obtain a rock-soil stability coefficient.

[0095] It should be noted that the calculation and normalization of the slope are existing technologies and will not be described in detail.

[0096] It should be noted that in an embodiment of the present application, when the length of the displacement stable period obtained based on the APCA segmentation algorithm is 24h, it indicates that the rock-soil layer state at the corresponding monitoring point in the preset historical period is unstable, and the rock-soil stability coefficient at the monitoring point is directly set to 0.

[0097] Step S4, at the current monitoring time, according to the potential danger factor of each monitoring point and the rock-soil stability coefficient in each displacement stable period, and combining the time interval between the end time of the displacement stable period and the current monitoring time, the attention coefficient of each monitoring point is obtained.

[0098] Considering that at the current monitoring moment, the smaller the geotechnical stability coefficient of each monitoring point is in each offset stable period, and the greater the potential dangerous factor is, the greater the possibility of subsequent dangerous offset is, the more unstable the geotechnical state is, and the more attention should be paid to the monitoring point; and considering that the closer the end point of the offset stable period is to the current monitoring moment, the greater the influence and reference of the geotechnical state in the offset stable period on the current monitoring moment are; therefore, the offset attention weight of each monitoring point is obtained at the current moment in the embodiment of the present application, wherein the offset attention weight represents the reference value provided by the offset amount at the monitoring point for evaluating the offset condition of the measured foundation support surface.

[0099] Based on this, in a preferred embodiment of the present application, the method for obtaining the attention coefficient comprises:

[0100] For each monitoring point, the time interval between the end point moment of each offset stable period and the current monitoring moment is negatively correlated and normalized to obtain the reference weight of each offset stable period, the geotechnical stability coefficient of the monitoring point in the corresponding offset stable period is weighted and summed by using the reference weight, and the negatively correlated normalization result of the weighted sum value is taken as the dangerous offset parameter of the monitoring point; at the current monitoring moment, the dangerous offset parameter is weighted by using the potential dangerous factor of each monitoring point, and the weighted result is taken as the attention coefficient of the corresponding monitoring point.

[0101] As an example, for each monitoring point, the time interval is mapped into an exponential function exp(-x) with natural constant e as the base number for negatively correlated normalization and adjustment logic to obtain the reference weight of the corresponding offset stable period, then the geotechnical stability coefficient of the monitoring point in the corresponding offset stable period is weighted and summed by using the reference weight, and the weighted sum value is mapped into the function 1-norm(x) as the independent variable x for negatively correlated normalization to obtain the dangerous offset parameter; wherein norm() is a linear normalization function; finally, the potential dangerous factor of the monitoring point at the current monitoring moment is multiplied with the dangerous offset parameter to obtain the attention coefficient.

[0102] Step S5, based on the attention coefficients and the offset amounts of all monitoring points, the overall offset amount of the measured foundation support surface is evaluated.

[0103] After obtaining the attention coefficient of each monitoring point, the overall offset amount of the measured foundation support surface can be further evaluated in combination with the offset amount of the monitoring point.

[0104] Preferably, in an embodiment of the present application, the method for evaluating the overall offset amount of the measured foundation support surface comprises:

[0105] At the current monitoring moment, the attention coefficient of each monitoring point is normalized to obtain the attention weight of each monitoring point, wherein the sum of the attention weights of all monitoring points is 1; the displacement at the corresponding monitoring point is weighted and summed by using the attention weight, and the weighted sum value is taken as the overall displacement of the foundation pit supporting surface to be measured.

[0106] As an example, the attention coefficients of all monitoring points are normalized by using a softmax function, and the normalized values are taken as the attention weights of the corresponding monitoring points; wherein the sum of all normalized values is 1 by using the softmax function; finally, the displacement at the corresponding monitoring point is weighted by using all attention weights, and the weighted sum result is taken as the overall displacement of the foundation pit supporting surface to be measured.

[0107] It should be noted that the implementer can also use other normalization methods, which are all prior art and will not be described in detail.

[0108] In an embodiment of the present application, if the overall displacement exceeds the preset threshold value such as 10mm at the current monitoring moment, the early warning mechanism is immediately started, relevant personnel and departments are notified, and appropriate emergency measures are taken, such as suspending construction, reinforcing the supporting structure, etc.

[0109] The present application also provides a foundation pit supporting displacement detection system applied to geotechnical engineering, which comprises a data acquisition module 101, a monitoring analysis module 102 and a displacement evaluation module 103; wherein the data acquisition module 101 is used to execute step S1 in the above-mentioned foundation pit supporting displacement detection method applied to geotechnical engineering, the monitoring analysis module 102 is used to execute steps S2-S4 in the above-mentioned foundation pit supporting displacement detection method applied to geotechnical engineering, and the displacement evaluation module 103 is used to execute step S5 in the above-mentioned foundation pit supporting displacement detection method applied to geotechnical engineering.

[0110] The present application also provides a foundation pit supporting displacement detection device applied to geotechnical engineering, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to realize the steps of the above-mentioned foundation pit supporting displacement detection method applied to geotechnical engineering.

[0111] To sum up, the present application collects the offset at each monitoring point on the to-be-tested foundation pit supporting surface at each monitoring moment, and obtains all offset regions in the to-be-tested foundation pit supporting surface, further obtains the dangerous coefficient of each offset region, and obtains the potential dangerous factor of each monitoring point; at each monitoring point, a plurality of offset stable periods are determined, the change characteristics of the stress value and the offset in each offset stable period are further analyzed, and the rock-soil stability coefficient at the monitoring point in each offset stable period is obtained; then at the current monitoring moment, the attention coefficient of each monitoring point is obtained, and finally the overall offset of the to-be-tested foundation pit supporting surface is evaluated in combination with the offset of the monitoring point. The present application evaluates the potential dangerous factor of the monitoring point based on the proximity of the monitoring point to the offset region, further evaluates the rock-soil stability in combination with the stress change at the monitoring point, evaluates the representativeness of each monitoring point to the foundation pit supporting offset, that is, the attention coefficient thereof, and thus accurately evaluates the overall offset of the foundation pit supporting in combination with the offset, thereby ensuring the accuracy of the offset detection of the foundation pit supporting in the rock-soil engineering.

[0112] It should be noted that the above-mentioned sequence of the embodiments of the present application is only for description, and does not represent 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.

[0113] 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 mainly describes the difference from other embodiments.

Claims

1. A method for detecting the offset of a foundation pit support applied to geotechnical engineering, characterized in that, The method comprises: At each monitoring time, the offset of each monitoring point on the to-be-tested foundation pit supporting surface is collected, and all offset regions in the to-be-tested foundation pit supporting surface are determined based on the offset; the stress value at each monitoring point is collected in real time; At each monitoring time, the dangerous coefficient of each offset region is obtained according to the distribution change of the offset of all monitoring points in each offset region and the distribution of the offset region, and the potential dangerous factor of each monitoring point is obtained according to the offset of each monitoring point, the dangerous coefficient and the position distribution of the offset region in the preset neighborhood, and the area and the dangerous coefficient of each offset region in the to-be-tested foundation pit supporting surface; At each monitoring point, the preset historical period of the offset at the current monitoring time is divided into a plurality of offset stable periods according to the fluctuation of the offset in each offset stable period and the change characteristics of the stress value and the offset in each offset stable period, and the geotechnical stability coefficient of the monitoring point in each offset stable period is obtained; At the current monitoring time, the attention coefficient of each monitoring point is obtained according to the potential dangerous factor of each monitoring point and the geotechnical stability coefficient in each offset stable period, and the time interval between the end time of the offset stable period and the current monitoring time; The overall offset of the to-be-tested foundation pit supporting surface is evaluated based on the attention coefficients and the offsets of all monitoring points.

2. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The offset region acquisition method comprises: At each monitoring time, each monitoring point is taken as a pixel point, the corresponding offset is taken as a pixel value, an offset field image corresponding to the to-be-tested foundation pit supporting surface is fitted by interpolation, the offset field image is segmented based on a watershed algorithm, and each non-catchment basin in the offset field image is taken as a region corresponding to the to-be-tested foundation pit supporting surface as an offset region.

3. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The dangerous coefficient acquisition method comprises: In each offset region, the monitoring point corresponding to the maximum offset is taken as an offset peak point, the offset activation parameter is obtained according to the deviation of the offset corresponding to each monitoring point on the region boundary relative to the maximum offset and the distance between each monitoring point on the region boundary and the offset peak point; At each monitoring time, any offset region is taken as a target region, a preset number of offset regions closest to the target region are selected as reference regions, the neighborhood offset set parameter of the target region is obtained according to the distance between each reference region and the target region; The dangerous coefficient of the corresponding offset region is obtained by fusing the offset activation parameter and the neighborhood offset set parameter.

4. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The potential dangerous factor acquisition method comprises: At each monitoring time, the first offset parameter is obtained according to the concentration characteristics of the offset of all monitoring points, the area proportion of all offset regions in the to-be-tested foundation pit supporting surface is taken as the second offset parameter, the third offset parameter is obtained according to the concentration characteristics of the dangerous coefficients of all offset regions, and the offset severity coefficient of the to-be-tested foundation pit supporting surface is obtained by fusing the first offset parameter, the second offset parameter and the third offset parameter; At each monitoring moment, the displacement region closest to each monitoring point is taken as the dangerous influence region of each monitoring point, the distance between each monitoring point and the corresponding dangerous influence region is negatively correlated to obtain a dangerous weight, the dangerous weight is used to weight the dangerous coefficient of the corresponding dangerous influence region to obtain a dangerous influence parameter of each monitoring point; At each monitoring moment, the dangerous influence parameter of each monitoring point and the corresponding displacement are fused to obtain an initial dangerous factor of each monitoring point, and the initial dangerous factor of each monitoring point is weighted by the displacement severity coefficient of the to-be-tested foundation pit supporting surface to obtain a potential dangerous factor of each monitoring point.

5. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The method for obtaining the displacement stable period comprises: At each monitoring point, a time sequence of the displacement at the monitoring point in a preset historical period is fitted, the time sequence is segmented based on an APCA segmentation algorithm, and each segmented period is taken as a displacement stable period.

6. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The method for obtaining the geotechnical stability coefficient comprises: In each displacement stable period of each monitoring point, a stress value time sequence is fitted, the stress value time sequence is divided into a first sequence subsegment and a second sequence subsegment by using a minimum stress value; a first stress stability factor is obtained according to the occurrence moment of the maximum stress value in the first sequence subsegment and the downward trend of the stress value after the occurrence moment; a second stress stability factor is obtained according to the occurrence moment of the maximum stress value in the second sequence subsegment and the upward trend of the stress value before the occurrence moment; In each displacement stable period of each monitoring point, a stability weight is obtained according to the concentration characteristics of the displacement at all monitoring moments, the first stress stability factor and the second stress stability factor are fused, the stability weight is used to weight the fusion result to obtain a first stability parameter, the normalized result of the length of the displacement stable period is taken as a second stability parameter, and the negative correlation normalized result of the change slope of the displacement at all monitoring moments is taken as a third stability parameter; The first stability parameter, the second stability parameter and the third stability parameter are fused to obtain the geotechnical stability coefficient of the monitoring point in each displacement stable period.

7. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The method for obtaining the attention coefficient comprises: For each monitoring point, the time interval between the end moment of each displacement stable period and the current monitoring moment is negatively correlated and normalized to obtain a reference weight of each displacement stable period, the reference weight is used to weight and sum the geotechnical stability coefficient of the monitoring point in the corresponding displacement stable period, and the negative correlation normalized result of the weighted sum value is taken as a dangerous displacement parameter of the monitoring point; at the current monitoring moment, the dangerous displacement parameter is weighted by the potential dangerous factor of each monitoring point, and the weighted result is taken as the attention coefficient of the corresponding monitoring point.

8. The method for detecting the offset of the foundation pit support applied to geotechnical engineering according to claim 1, characterized in that, The method for evaluating the overall displacement of the to-be-tested foundation pit supporting surface comprises: At the current monitoring moment, the attention coefficient of each monitoring point is normalized to obtain an attention weight of each monitoring point, wherein the sum of the attention weights of all monitoring points is 1; the attention weight is used to weight and sum the displacement of the corresponding monitoring point, and the weighted sum value is taken as the overall displacement of the to-be-tested foundation pit supporting surface.

9. A foundation pit support offset detection system applied to geotechnical engineering, the system comprising: a data acquisition module: at each monitoring time, the offset at each monitoring point on the foundation pit support surface to be measured is collected, and all offset regions in the foundation pit support surface to be measured are determined based on the offset; real-time acquisition of stress values at each monitoring point; a monitoring analysis module: at each monitoring time, the dangerous coefficient of each offset region is obtained according to the distribution change of the offset at all monitoring points in each offset region and the distribution of the offset region, and the potential dangerous factor of each monitoring point is obtained according to the offset at each monitoring point, the dangerous coefficient and the position distribution of the offset region in the preset neighborhood, and the area and the dangerous coefficient of each offset region in the foundation pit support surface to be measured; at each monitoring point, the preset historical period is divided into several offset stable periods according to the fluctuation of the offset in the preset historical period at the current monitoring time, and the geotechnical stability coefficient at the monitoring point in each offset stable period is obtained according to the length of each offset stable period and the change characteristics of the stress value and the offset in each offset stable period; at the current monitoring time, the attention coefficient of each monitoring point is obtained according to the potential dangerous factor of each monitoring point and the geotechnical stability coefficient in each offset stable period, combined with the time interval between the endpoint time of the offset stable period and the current monitoring time; an offset evaluation module: based on the attention coefficient and the offset of all monitoring points, the overall offset of the foundation pit support surface to be measured is evaluated.

10. A device for detecting the amount of displacement of a foundation pit support for geotechnical engineering, the device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the foundation pit support offset detection method applied to geotechnical engineering according to any one of claims 1-8.

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