Foundation pit intelligent monitoring test method and device

Abstract

The present application belongs to the technical field of foundation pit engineering monitoring, and relates to a kind of foundation pit intelligent monitoring test method and equipment, which constructs the multi-physical quantity monitoring sequence of time sequence alignment by supporting member mechanical response parameter and medium mechanical response parameter, and establishes mechanical transmission path combined with spatial geometric relationship, can bring originally dispersed monitoring data into the same transmission link for analysis;By extracting the load transmission coefficient and constraint stiffness characteristics of each constraint node, a supporting member-medium coupling response characteristic matrix is constructed, providing a unified feature base for the establishment of theoretical transfer function, and based on the theoretical transfer function at each constraint node, the corresponding overall theoretical response envelope is established, which avoids false alarm or false alarm caused by relying on fixed threshold;By the over-limit combination state of supporting member response deviation and medium mechanical response deviation, the abnormal cause is determined as supporting member problem, medium change problem or supporting member and medium coupling failure problem.

Description

Technical Field

[0001] This invention belongs to the field of foundation pit engineering monitoring technology, specifically a test method and equipment for intelligent monitoring of foundation pits. Background Technology

[0002] During the excavation of the foundation pit, the support components bear lateral earth pressure, water pressure, and construction disturbance loads. The stress release, displacement evolution, and interface contact state of the medium will in turn affect the stress and deformation of the support components. Therefore, how to continuously monitor and accurately identify the coupling response between the foundation pit support system and the medium has become an important technical issue to ensure construction safety and control engineering risks.

[0003] Currently, foundation pit safety monitoring is mainly divided into two categories: monitoring of the support structure itself and monitoring of the surrounding medium. In existing technologies, multi-source sensing units are usually deployed on support components such as support piles, anchors, and diaphragm walls, and the monitoring results are compared with preset warning thresholds to determine whether the foundation pit is in a safe state.

[0004] However, existing technologies still have the following limitations: 1. Existing technologies usually treat the mechanical response of the support structure and the mechanical response of the medium separately, and fail to establish a quantitative correlation between the two based on the mechanical transmission path, making it difficult to form a complete mechanical process that reflects the load from the medium to the support structure and then layer by layer within the support structure.

[0005] 2. Existing monitoring methods mainly rely on the judgment of exceeding the limit of a single measuring point or a single physical quantity, and do not give enough consideration to the transmission relationship between the support component response and the medium response. As a result, although abnormal phenomena can be detected, it is difficult to distinguish whether the abnormality originates from the support component itself, the change in the state of the medium, or the instability of the coupling relationship between the two. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, embodiments of the present invention provide a method and equipment for intelligent monitoring of foundation pits, which can effectively solve the problems involved in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions: On the one hand, this invention provides a method for intelligent monitoring of foundation pits, including: acquiring the mechanical response parameters of the support components and the mechanical response parameters of the medium, and constructing a time-aligned multi-physical quantity monitoring sequence.

[0008] Based on the spatial geometric relationship between the foundation pit support structure and the medium, a mechanical transmission path is established, and the load transmission coefficient and constraint stiffness characteristics of each constraint node are extracted.

[0009] By integrating monitoring sequences of multiple physical quantities, load transfer coefficients, and constraint stiffness characteristics, a support component-medium coupling response characteristic matrix is ​​constructed.

[0010] The theoretical transfer function at each constraint node is determined based on the mechanical transmission path, and the overall theoretical response envelope of the mechanical response of the support and the medium under normal conditions is constructed.

[0011] The measured mechanical response vectors of each constraint node in the support-medium coupling response feature matrix at each sampling time are obtained and compared with the corresponding overall theoretical response envelope to determine the support response deviation and the medium mechanical response deviation.

[0012] The cause of the anomaly can be determined by the deviation between the support component response and the mechanical response of the medium, which may be a problem with the support component, a problem with the change in the medium, or a problem with the coupling failure between the support component and the medium.

[0013] On the other hand, the present invention provides an intelligent monitoring test device for foundation pits, comprising: a data acquisition and construction module, a path feature module, a matrix construction module, an envelope construction module, a deviation decomposition module, and an anomaly diagnosis module.

[0014] The acquisition and construction module is connected to the path feature module and the matrix construction module respectively; the path feature module is connected to the matrix construction module; the matrix construction module is connected to the envelope construction module; the envelope construction module is connected to the deviation decomposition module; and the deviation decomposition module is connected to the matrix construction module and the anomaly diagnosis module respectively.

[0015] The data acquisition module obtains the mechanical response parameters of the support components and the mechanical response parameters of the medium, and constructs a time-aligned multi-physical quantity monitoring sequence.

[0016] The path feature module establishes a mechanical transfer path based on the spatial geometric relationship between the foundation pit support structure and the medium, and extracts the load transfer coefficient and constraint stiffness characteristics of each constraint node.

[0017] The matrix construction module integrates multi-physical quantity monitoring sequences, load transfer coefficients, and constraint stiffness characteristics to construct a support component-medium coupling response characteristic matrix.

[0018] The envelope construction module determines the theoretical transfer function at each constraint node based on the mechanical transmission path, and constructs the overall theoretical response envelope of the mechanical response of the support and the medium under normal conditions.

[0019] The deviation decomposition module obtains the measured response vectors of each constraint node in the support-medium coupling response feature matrix at each sampling time and compares them with the corresponding overall theoretical response envelope to determine the support response deviation and the medium mechanical response deviation.

[0020] The anomaly diagnosis module determines the cause of the anomaly based on the deviation of the support component response and the deviation of the medium mechanical response, whether it is a problem with the support component, a problem with the medium change, or a problem with the coupling failure between the support component and the medium.

[0021] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: (1) The present invention constructs the mechanical response parameters of the support component and the mechanical response parameters of the medium into a time-aligned multi-physical quantity monitoring sequence, and establishes a mechanical transmission path in combination with spatial geometric relationship, so as to incorporate the originally scattered monitoring data into the same transmission link for analysis, so as to more accurately reflect the interaction relationship between the support component and the medium.

[0022] (2) This invention extracts the load transfer coefficient and constraint stiffness characteristics of each constraint node, constructs the support-medium coupling response characteristic matrix, provides a unified characteristic basis for the establishment of the theoretical transfer function, and establishes the corresponding overall theoretical response envelope based on the theoretical transfer function at each constraint node, providing a dynamic theoretical benchmark for different construction stages and node positions, and avoiding false alarms or missed alarms caused by relying on fixed thresholds.

[0023] (3) This invention decomposes the measured response into the support component response deviation and the medium mechanical response deviation, and determines the cause of the abnormality as a support component problem, a medium change problem, or a support component and medium coupling failure problem based on the over-limit combination state of the two, so as to provide a clearer basis for handling on-site reinforcement, unloading, supplementary testing and construction adjustment. Attached Figure Description

[0024] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0026] Figure 2 This is a flowchart of the method for extracting load transfer coefficient and constraint stiffness characteristics according to the present invention.

[0027] Figure 3 This is a module connection diagram of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Reference Figure 1As shown, in a first aspect, the present invention provides a method for intelligent monitoring of foundation pits, including: S1, acquiring mechanical response parameters of support components and mechanical response parameters of the medium, and constructing a time-aligned multi-physical quantity monitoring sequence.

[0030] In this embodiment, the foundation pit support system uses the retaining wall as the main support component. The supporting components are connected to the retaining wall to form a support structure. The outer side of the retaining wall is covered with soil and rock media that transmit forces to it. Along the extension direction of the foundation pit, the corresponding cross-section where the internal force reaches the local peak position in the design calculation results of the support structure is taken as a typical monitoring cross-section, and corresponding monitoring devices for the support component and the medium are established in each typical monitoring cross-section.

[0031] The mechanical response parameters of the support components include the strain and displacement values ​​of the support components, while the mechanical response parameters of the medium include the soil pressure and deep horizontal displacement values ​​of the corresponding medium.

[0032] The strain values ​​of the support components are directly collected by strain sensors embedded inside the support components. The strain sensors are arranged in layers at a preset interval along the depth direction of the support components. The preset interval is half of the vertical spacing between adjacent support components, and the strain sensors are densely arranged at the peak bending moment depth position in the design calculation results of the support structure. The displacement values ​​of the support components are obtained by collecting inclination angle data at different depths from inclinometers fixedly connected to the support components, and the inclination angle data is integrated and converted along the depth direction.

[0033] The soil pressure value of the medium is directly measured by soil pressure sensors embedded in the medium outside the support member at the connection position of the support member and the boundary position of the soil-rock layer, and the horizontal distance between them and the outer surface of the support member is recorded; the horizontal displacement value of the deep medium is obtained by collecting the inclination angle data at different depths from the inclination boreholes set in the medium outside the support member at the corresponding typical monitoring section, and then converting it by layer integration.

[0034] The monitoring platform receives the mechanical response parameters of the support components and the mechanical response parameters of the medium every ten minutes and timestamps them with a unified clock. For short-term missing data at individual sampling moments, the average of two adjacent moments is used to fill in the missing data, thus forming a multi-physical quantity monitoring sequence indexed by time.

[0035] S2. Based on the spatial geometric relationship between the foundation pit support structure and the medium, establish the mechanical transmission path and extract the load transmission coefficient and constraint stiffness characteristics of each constraint node.

[0036] Considering that the foundation pit support structure and the medium are not isolated stress-bearing entities, but form a mechanical coupling through the contact interface, it is difficult to construct a complete mechanical mechanism for the load to be transferred from the medium to the support structure and then layer by layer within the support structure by relying solely on data from discrete monitoring sections. If a quantitative description of the mechanical transmission path is missing, it is impossible to correlate the response parameters obtained from each monitoring point to the specific force transmission link. Subsequent anomaly diagnosis will find it difficult to distinguish whether the response deviation originates from local medium changes, problems with the support components themselves, or coupling failure at the interface between the two.

[0037] The process of establishing the mechanical transmission path includes: First, constructing a spatial geometric model based on the spatial position parameters and geometric shape parameters of the support component, and constructing a layered spatial model based on the spatial distribution parameters and interface position parameters of the medium. Specifically, the process is as follows: a spatial geometric model is established based on the top elevation, bottom burial depth, cross-sectional dimensions, and connection position of the support component. Based on the plane coordinates, burial depth coordinates, and horizontal distances relative to the outer surface of the support component of each strain sensor, inclinometer tube, earth pressure sensor, and inclinometer hole in the aforementioned typical monitoring section, a set of spatial coordinates of monitoring points is constructed in the spatial geometric model. Then, a layered spatial model is established based on the layer distribution of each layer of medium in the exploration profile.

[0038] Then, a spatial overlay analysis is performed on the spatial geometric model and the layered spatial model. The specific process is as follows: within the same typical monitoring section, the outer contour line of the support component, the connection position of the support component, the boundary of each soil and rock layer, and the spatial coordinates of the monitoring point are uniformly projected onto the same depth coordinate system.

[0039] The top embedment depth of the outer surface of the support component is denoted as... The bottom burial depth is recorded as , will the The top boundary burial depth of the layered rock and soil is denoted as The bottom boundary is buried deep as Then take and The larger value in the interval is taken as the upper boundary of the intersection. and The smaller value in the interval is taken as the lower boundary of the intersection. When the upper boundary of the intersection is smaller than the lower boundary, the depth interval between the upper and lower boundaries of the intersection is defined as the distance between the outer surface of the support member and the first... The intersection of rock and soil layers.

[0040] It should be noted that all burial depth values ​​are taken with the ground surface as the zero point and downward as the positive value.

[0041] Each intersection interval is defined as a contact zone, and the earth pressure sensor and inclinometer monitoring layer located in the intersection interval are mapped to the contact zone.

[0042] Since the support member in this embodiment is under lateral compression and bending stress under the action of the soil and rock medium, and the adjacent soil and rock layer is located on one side of the outer surface of the support member, the boundary of the outer surface of the support member adjacent to the corresponding soil and rock layer in each contact section is determined as the effective boundary of the contact section.

[0043] Next, the ratio of the difference in strain value between adjacent monitoring layers in each contact section to the difference in corresponding depth is calculated as the strain difference change rate of the support component. The location where the change rate exceeds the preset threshold is identified as the location where the stress state changes abruptly, and it is identified as the constraint part.

[0044] Obtain the spatial coordinates corresponding to each constraint part as candidate constraint nodes. Determine the normal direction from the outer medium of the support to the inner side of the support as the load direction, and take this load direction as the main force direction of each candidate constraint node.

[0045] All candidate constraint nodes are arranged in ascending order of burial depth, and the candidate constraint node with the smallest burial depth is determined as the load application start node.

[0046] For the current candidate constraint node, read the spatial coordinates of its next candidate node in turn, and construct the direction of the line connecting the current candidate constraint node to the next candidate constraint node.

[0047] If the angle between the direction of the connecting line and the main force direction of the current candidate constraint node is no greater than 90 degrees, then it is determined that there is a force transmission relationship between the current candidate constraint node and the next candidate constraint node, and the direction of the connecting line is determined as the force transmission direction.

[0048] Finally, the candidate constraint nodes with force transmission relationships are connected sequentially from top to bottom to form a force transmission path.

[0049] It is understandable that an angle of no more than 90 degrees indicates that the candidate next node is within the forward transmission range of the main force direction of the current node; when the angle is greater than 90 degrees, it means that the direction is opposite to the main force direction and does not conform to the load transmission law, so it is not regarded as the force transmission direction.

[0050] It should be noted that the preset threshold is set directly based on engineering experience and soil conditions, and the value range is usually from 0.01 / m to 0.05 / m. Implementers can customize the setting according to actual requirements.

[0051] It should also be noted that the geometric relationship between the support component and the medium is quantified into the intersection of depth intervals through the above spatial overlay analysis, providing a spatial basis for the identification of contact sections, connection parts and constraint parts; by comparing the rate of change of strain difference with a preset threshold, the quantitative identification of constraint parts is realized, providing a node location basis for the subsequent extraction of load transfer coefficients; by establishing the force transmission relationship between candidate constraint nodes, the topological structure of load transfer of the support component is formed, providing node association relationships for the construction of the support component-medium coupling response feature matrix.

[0052] Reference Figure 2 As shown, the process of extracting the load transfer coefficient and constraint stiffness characteristics of each constraint node is as follows: calculate the ratio of the strain value of the support member and the soil pressure value at each constraint node at the same time, and take the median of the ratios at multiple times as the load transfer coefficient.

[0053] The relative displacement difference between the support member displacement value and the deep horizontal displacement value of the medium at each constraint node is calculated at the same moment. The interaction force between the support member and the medium is determined based on the nodal bending moment and distributed reaction force intensity obtained from the strain value of the support member. The specific process is as follows: First, based on the... The bending moment at the cross-section of a given constraint node is calculated using the strain values ​​of the support member at each constraint node. The formula for this calculation is as follows: .

[0054] in Indicates the first At each constraint node, at time... The bending moment of the section reflects the bending internal force borne by the support member at that location; The elastic modulus of a support component material represents its ability to resist elastic deformation. It is determined by the physical properties of the materials used in the support component (such as steel, concrete, etc.). For example, concrete has an elastic modulus of approximately [value missing]. ; The moment of inertia representing the cross-section of a support member is a measure of the cross-sectional geometry's resistance to bending stiffness. It is related to the cross-sectional dimensions and shape; for example, for a rectangular cross-section, the moment of inertia... Where b is the width and h is the height; Indicates the first At each constraint node, at time... The strain value was obtained by actual measurement using strain sensors embedded in the support components; This represents the distance from the strain sensor to the neutral axis of the support section. The neutral axis is the axis along which the stress is zero when the section is in pure bending. The value depends on the sensor's installation position on the cross section.

[0055] In this formula, The bending stiffness of the support components reflects their ability to resist bending deformation. The larger the value, the greater the bending moment generated under the same strain. This represents the cross-sectional curvature calculated from the strain value. According to the plane section assumption, the bending strain is proportional to the distance from the neutral axis.

[0056] The overall formula is based on the bending theory in mechanics of materials. It calculates the bending moment of the section by back-calculating the strain through actual measurement, realizing the quantitative conversion from local strain to overall internal force.

[0057] Next, based on the section bending moments of the three adjacent constraint nodes at the same moment, the second-order difference calculation is used along the depth direction of the support member to calculate the... The distributed reaction force intensity at each constraint node.

[0058] The formula for calculating the distributed reaction strength is: .

[0059] in, Indicates the first At each constraint node, at time... The distributed reaction strength (reaction force per unit length) reflects the magnitude of the distributed load exerted by the medium on the support member along the depth direction at that node location; , They respectively represent the first Bending moment at the cross section of the two adjacent nodes above and below each node; This represents the vertical spacing between adjacent constraint nodes, i.e., the discretization step size along the depth direction of the support component.

[0060] In this formula, This constitutes a second-order central difference of the bending moment along the depth direction, which is approximately equal to the second derivative of the bending moment with respect to the depth coordinate and is proportional to the intensity of the distributed load.

[0061] Divide by The difference result is transformed into the distribution reaction strength. The dimensionally consistent values ​​enable an approximate conversion from discrete bending moments to continuous distributed loads.

[0062] Finally, the distributed reaction strength Multiply by the first Vertical spacing corresponding to each constraint node The interaction force between the support components and the medium in the section where the node is located is obtained.

[0063] With the first The interaction force of each constraint node at each sampling time is used as the ordinate and the relative displacement difference as the abscissa. The data points corresponding to each time are connected in sequence according to the sampling time to construct the force-displacement relationship curve of the node.

[0064] The curvature of the force-displacement relationship curve at the intermediate sampling point is calculated based on three adjacent sampling points. The method for calculating the curvature at the intermediate point is as follows: For three consecutive sampling points on the force-displacement relationship curve, they are denoted as the previous point, the intermediate point, and the next point, respectively, where the horizontal axis represents the relative displacement difference and the vertical axis represents the interaction force.

[0065] Calculate the slope from the previous point to the midpoint and the slope from the midpoint to the next point, and calculate the absolute value of the difference between these two slopes.

[0066] Divide the absolute value of the difference by the square of the horizontal coordinate span between the first and third points. The result is the curvature at the intermediate point. By traversing all consecutive combinations of three points in this way, the curvature at each intermediate sampling point can be obtained, and the relative displacement difference corresponding to the maximum curvature is taken as the inflection point displacement.

[0067] Using the inflection point displacement as the boundary, the force-displacement relationship curve is divided into an interval before the inflection point and an interval after the inflection point. Each interval contains multiple sampling points. Then, within each interval, the instantaneous stiffness value is calculated according to the ratio of the increment of the interaction force between two adjacent sampling points to the increment of the relative displacement difference. The average value of all instantaneous stiffness values ​​within the same interval is then taken to obtain the first value. The constraint stiffness characteristics corresponding to each constraint node.

[0068] It should be noted that, since the curvature of the support-medium interaction force-displacement curve will continue to increase to the maximum value and then decrease after entering the plastic stage, the point of maximum curvature is taken as the inflection point displacement, which characterizes the moment when the interface slippage or local yielding is most intense, and this is used as the boundary of the constraint stiffness segment.

[0069] S3. The multi-physical quantity monitoring sequence is integrated with the load transfer coefficient and constraint stiffness characteristics to construct the support component-medium coupling response characteristic matrix.

[0070] The above construction process is as follows: by using the position of each constraint node in the mechanical transmission path and its corresponding depth coordinates, the strain monitoring data, support displacement monitoring data, earth pressure monitoring data and deep displacement monitoring data of the medium corresponding to the depth coordinates in the multi-physical quantity monitoring sequence are extracted to form the node monitoring sub-sequence corresponding to each constraint node.

[0071] According to the preset sampling cycle, the strain value of the support component, the displacement value of the support component, the soil pressure value of the medium, and the horizontal displacement value of the deep medium at each sampling time are extracted sequentially from the monitoring subsequence of this node.

[0072] The load transfer coefficient and constraint stiffness characteristics of the node are used as static characteristic parameters and mapped to each sampling moment of the node monitoring subsequence according to the same time index, so that the mechanical response parameters of the support component, the mechanical response parameters of the medium, the load transfer coefficient and the constraint stiffness characteristics correspond one-to-one at the same sampling moment, thus completing the time sequence alignment.

[0073] The mechanical response parameters, medium mechanical response parameters, load transfer coefficients, and constraint stiffness characteristics of the support components after time alignment are subjected to extreme value normalization to eliminate the numerical differences between the characteristic parameters caused by different dimensions.

[0074] After normalization, the normalized support strain value, support displacement value, soil pressure value, deep horizontal displacement value, load transfer coefficient and constraint stiffness characteristics of each constraint node at the same time are directly constructed into a coupled feature vector in a fixed order using the feature splicing method.

[0075] Arrange the coupling feature vectors according to the order of sampling time as the time dimension and according to the order of constraint nodes in the mechanical transmission path as the spatial dimension to form the support component-medium coupling response feature matrix.

[0076] It should be noted that the preset sampling period is set to 10 minutes, based on the requirements of the current national technical standards for monitoring foundation pit engineering.

[0077] It should also be noted that by structurally integrating time-series monitoring data with nodal mechanical characteristic parameters, a support-medium coupling response characteristic matrix is ​​formed with constraint nodes as spatial indices and sampling times as time indices, providing a unified data foundation for subsequent deviation analysis between measured and theoretical responses.

[0078] Considering that subsequent steps require comparing the measured response with the theoretical response under normal conditions to quantify the response deviation of the support components and the response deviation of the medium mechanical transmission, and thus identify the cause of the anomaly, the normal condition refers to the continuous 24 hours from the excavation of the foundation pit to the completion of the first support installation and before the start of subsequent working conditions.

[0079] Based on this, S4, according to the mechanical transmission path, determine the theoretical transfer function at each constraint node, and construct the theoretical response envelope of the mechanical response of the support and the medium under normal conditions.

[0080] The process of determining the theoretical transfer function at each constraint node is as follows: extract the coupling feature vector of each constraint node from the support-medium coupling response feature matrix and construct a sample set.

[0081] Constraint nodes in the mechanical transmission path are numbered sequentially from top to bottom. For the current constraint node, the constraint node that is located before the current node in the transmission direction, is directly adjacent to the current node, and has a directed transmission edge pointing from the current node to the current node is determined as the upstream associated node of the current node.

[0082] Each sampling moment in the sample set is considered a sample unit, and the data of the upstream associated node and the current node at the same sampling moment are paired one by one. For each sample unit, training samples are constructed according to two types of responses: support component and medium mechanics. The support component mechanical response parameters and medium mechanics response parameters corresponding to the upstream associated node are used as input terms, and the support component response vector and medium mechanics response vector corresponding to the current node are used as output terms. The load transfer coefficient and constraint stiffness characteristics of the current node are added to the input terms to form the corresponding training samples.

[0083] Arrange the input items corresponding to all sampling times in the sample set by row to form the support component input sample matrix and the medium mechanics input sample matrix; arrange the corresponding output items by row to form the support component output sample matrix and the medium mechanics output sample matrix.

[0084] The least squares method is used to solve the regression coefficient matrix with the input sample matrix as the independent variable and the output sample matrix as the dependent variable. Each column of the regression coefficient matrix corresponds to an output variable, and each row corresponds to the influence weight of an input variable on the corresponding output variable.

[0085] The input variables include the strain value and displacement value of the upstream node, the load transfer coefficient, and the constraint stiffness characteristics. The output variables include the strain value and displacement value of the current node. The obtained regression coefficient matrix is ​​used to characterize the linear transfer relationship between the input and output variables at the current node and serves as the theoretical transfer function of the support component at the current node.

[0086] Using the same fitting method, with the medium mechanical response parameters of the upstream associated node as input and the medium mechanical response parameters of the current node as output, the medium theoretical transfer function at the current node is obtained.

[0087] It should be noted that before constructing the input and output sample matrices, extreme value normalization is performed on each input and output variable to map their values ​​to the interval [0, 1], thus eliminating the influence of dimensions. After solving the regression coefficient matrix, it is then inversely transformed back to the original dimensions based on the normalization parameters.

[0088] In a preferred embodiment of the present invention, the process of establishing the theoretical response envelope of the mechanical response of the support component and the medium under normal conditions is as follows: First, the support component input items corresponding to each sampling time in the sample set are substituted into the theoretical transfer function of the support component in sequence to obtain the theoretical mechanical response parameter sequence of the support component at each sampling time of the current node; according to the same logic as above, the theoretical mechanical response parameter sequence of the medium at each sampling time of the current node is obtained.

[0089] Subsequently, for the theoretical values ​​of strain and displacement of the support component in the theoretical mechanical response parameter sequence of the support component, the maximum value at all sampling times is taken as the upper limit and the minimum value as the lower limit, respectively, so as to construct the theoretical response envelope of strain and displacement of the support component at the current node; for the theoretical values ​​of earth pressure and deep horizontal displacement of the medium in the theoretical mechanical response parameter sequence of the medium, the theoretical response envelope of earth pressure and deep horizontal displacement of the medium at the current node is constructed according to the same logic.

[0090] Finally, the theoretical response envelopes of each support component and the theoretical response envelopes of each medium mechanics component corresponding to each constraint node are sequentially associated according to the node order to form the overall theoretical response envelope of the support component and the overall theoretical response envelope of the medium, respectively.

[0091] S5. Decompose the measured response in the support component-medium coupling response characteristic matrix into the support component response deviation and the medium mechanical response deviation.

[0092] In this embodiment, when the foundation pit construction continues and causes the support components and the medium response to change continuously, firstly, the measured coupling feature vector of the current node at the current sampling time is extracted from the support component-medium coupling response feature matrix, and the measured coupling feature vector is split into the support component measured response vector and the medium mechanical measured response vector according to the composition order.

[0093] Among them, the measured response vector of the support component consists of the measured strain and displacement of the support component at the current sampling time; the measured response vector of the medium mechanics consists of the measured soil pressure and the measured horizontal displacement of the deep layer of the medium at the current sampling time.

[0094] Subsequently, the overall theoretical response envelope of the support component and the overall theoretical response envelope of the medium corresponding to the current node are read, and the upper and lower limits of the overall theoretical response envelope of the support component and the overall theoretical response envelope of the medium at the current node are extracted respectively to form the upper limit vector and the lower limit vector.

[0095] Determine whether each component of the measured response vector of the support component and the measured response vector of the medium mechanics are within the range defined by the corresponding upper and lower limit vectors. If they are all within the corresponding range, the corresponding response deviation is recorded as zero. If there are components that exceed the corresponding envelope range, calculate the difference between each out-of-limit component and the corresponding envelope boundary value, and sum the differences of each out-of-limit component to obtain the corresponding support component response deviation or medium mechanics response deviation.

[0096] It should be noted that, through the above steps, abnormal deviations at the same node can be decomposed into structural (support) deviations and medium-side deviations, thus enabling the identification of the source of the deviation.

[0097] Reference Figure 3 As shown in Figure S6, based on the over-limit combination state of the support component response deviation and the medium mechanical response deviation relative to the corresponding theoretical response envelope, the cause of the anomaly is determined to be a support component problem, a medium change problem, or a support component and medium coupling failure problem.

[0098] In this embodiment, it is determined whether the support component response deviation and the medium mechanical response deviation of the current node at the current sampling time are greater than zero.

[0099] If only the support component response deviation is greater than zero, and the medium mechanical response deviation is equal to zero, then the anomaly at the current node is determined to be a support component problem.

[0100] If only the deviation of the medium mechanical response is greater than zero, and the deviation of the support component response is equal to zero, then the anomaly corresponding to the current node is determined to be a medium change problem.

[0101] If both the support component response deviation and the medium mechanical response deviation are greater than zero, then the cause of the anomaly at the current node is determined to be the failure of the support component coupled with the medium.

[0102] The response deviation of the support component, the mechanical response deviation of the medium, the anomaly type, the node location and the time of occurrence of the current node are written into the anomaly event record and output to the monitoring platform so that on-site technicians can take measures such as intensified monitoring, local reinforcement and adjustment of construction parameters.

[0103] It should be noted that, through the above implementation process, the present invention does not make isolated judgments on the support components and the medium, but rather conducts a unified analysis of the coupling state of the two along the mechanical transmission path, thereby enabling a more accurate differentiation between support component problems, medium change problems, and support component-medium coupling failure problems.

[0104] Secondly, the present invention provides an intelligent monitoring test device for foundation pits, comprising: a data acquisition and construction module, a path feature module, a matrix construction module, an envelope construction module, a deviation decomposition module, and an anomaly diagnosis module.

[0105] The acquisition and construction module is connected to the path feature module and the matrix construction module respectively; the path feature module is connected to the matrix construction module; the matrix construction module is connected to the envelope construction module; the envelope construction module is connected to the deviation decomposition module; and the deviation decomposition module is connected to the matrix construction module and the anomaly diagnosis module respectively.

[0106] The data acquisition module obtains the mechanical response parameters of the support components and the mechanical response parameters of the medium, and constructs a time-aligned multi-physical quantity monitoring sequence.

[0107] The path feature module establishes a mechanical transfer path based on the spatial geometric relationship between the foundation pit support structure and the medium, and extracts the load transfer coefficient and constraint stiffness characteristics of each constraint node.

[0108] The matrix construction module integrates multi-physical quantity monitoring sequences, load transfer coefficients, and constraint stiffness characteristics to construct a support component-medium coupling response characteristic matrix.

[0109] The envelope construction module determines the theoretical transfer function at each constraint node based on the mechanical transmission path, and constructs the overall theoretical response envelope of the mechanical response of the support and the medium under normal conditions.

[0110] The deviation decomposition module obtains the measured response vectors of each constraint node in the support-medium coupling response feature matrix at each sampling time and compares them with the corresponding overall theoretical response envelope to determine the support response deviation and the medium mechanical response deviation.

[0111] The anomaly diagnosis module determines the cause of the anomaly based on the deviation of the support component response and the deviation of the medium mechanical response, whether it is a problem with the support component, a problem with the medium change, or a problem with the coupling failure between the support component and the medium.

[0112] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A test method for intelligent monitoring of foundation pits, characterized in that, include: The mechanical response parameters of the support components and the mechanical response parameters of the medium are obtained and constructed into a time-aligned multi-physical quantity monitoring sequence; Based on the spatial geometric relationship between the foundation pit support structure and the medium, a mechanical transfer path is established, and the load transfer coefficient and constraint stiffness characteristics of each constraint node are extracted. The process is as follows: The mechanical response parameters of the support components include the strain and displacement values ​​of the support components, and the mechanical response parameters of the medium include the soil pressure and deep horizontal displacement values ​​of the corresponding medium. The above parameters are matched in time sequence. Calculate the ratio of the strain value of the support member to the soil pressure value at each constraint node at the same time, and take the median of the ratios at multiple times as the load transfer coefficient. Calculate the relative displacement difference between the support member displacement value and the deep horizontal displacement value of the medium at each constraint node at the same moment, and determine the interaction force between the support member and the medium based on the node bending moment and distributed reaction force intensity obtained from the strain value of the support member. A force-displacement relationship curve is constructed using the interaction force and the relative displacement difference. The curvature of the force-displacement relationship curve is calculated, and the relative displacement difference corresponding to the maximum curvature value is extracted as the inflection point displacement. Divide the intervals by using the inflection point displacement as the boundary, calculate the average value of the instantaneous stiffness value in each interval, and obtain the corresponding constraint stiffness characteristics; By integrating multi-physical quantity monitoring sequences, load transfer coefficients, and constraint stiffness characteristics, a support component-medium coupling response characteristic matrix is ​​constructed. The theoretical transfer function at each constraint node is determined based on the mechanical transmission path, and the overall theoretical response envelope of the mechanical response of the support and the medium under normal conditions is constructed. The measured mechanical response vectors of each constraint node in the support-medium coupling response feature matrix at each sampling time are obtained and compared with the corresponding overall theoretical response envelope to determine the support response deviation and the medium mechanical response deviation. The cause of the anomaly can be determined by the deviation between the support component response and the mechanical response of the medium, which may be a problem with the support component, a problem with the change in the medium, or a problem with the coupling failure between the support component and the medium.

2. The intelligent monitoring test method for foundation pits according to claim 1, characterized in that, The process of establishing a force transmission path includes: A spatial geometric model is constructed based on the spatial location and geometric shape parameters of the support components, and a layered spatial model is constructed based on the spatial distribution parameters and interface location parameters of the medium. A spatial overlay analysis was performed on the spatial geometric model and the layered spatial model, and the spatial intersection of the support components and the medium was taken as the contact section. The effective action boundary of each contact zone is determined based on the stress mode of the support component in each contact zone and its relative position to the adjacent soil and rock layers.

3. The intelligent monitoring test method for foundation pits according to claim 2, characterized in that, The process of establishing a force transmission path also includes: Calculate the rate of change of strain difference along the extension direction of the support in each contact section, and determine the location where the rate of change exceeds the preset threshold as the location where the stress state changes abruptly, and determine it as the constraint part. Obtain the spatial coordinates of each constraint part as candidate constraint nodes, and determine the main force direction of each candidate constraint node according to the load direction. Arrange all candidate constraint nodes in ascending order of burial depth, and determine the candidate constraint node with the smallest burial depth as the load application start node. Obtain the direction of the line connecting the current node and the next candidate node. If the angle between the line and the main force direction of the current node is not greater than 90 degrees, it is determined that there is a force transmission relationship between the current node and the next candidate node, and the direction from the current node to the next candidate node is determined as the transmission direction. If the angle is greater than 90 degrees, skip the next candidate node and continue to judge the next candidate constraint node. Connect all candidate constraint nodes that are confirmed to have force transmission relationships according to the transmission direction to form a force transmission path.

4. The intelligent monitoring test method for foundation pits according to claim 3, characterized in that, The process of constructing the support component-medium coupling response characteristic matrix is ​​as follows: Based on the position of each constraint node in the mechanical transmission path, node matching is performed on the multi-physical quantity monitoring sequence to obtain the node monitoring sub-sequence corresponding to each constraint node. The mechanical response parameters of the support components and the mechanical response parameters of the medium at each sampling time are extracted according to the preset sampling period; The load transfer coefficient and constraint stiffness characteristics of each constraint node are mapped to the corresponding node monitoring subsequence, and time-series aligned with the mechanical response parameters of the support components and the mechanical response parameters of the medium at each sampling time. The time-aligned feature parameters are normalized to generate the coupling feature vectors of each constraint node at each sampling time. Arrange the coupling feature vectors according to the time sequence and the node sequence of the mechanical transmission path to construct the support component-medium coupling response feature matrix.

5. The intelligent monitoring test method for foundation pits according to claim 4, characterized in that, The process of determining the theoretical transfer function at each constraint node is as follows: Extract the coupling feature vectors of each constraint node under normal conditions from the support component-medium coupling response feature matrix to construct a sample set; The upstream associated nodes of each constraint node are determined according to the node sequence. The mechanical response parameters of the support component and the mechanical response parameters of the medium corresponding to the upstream associated node are used as input items, and the response vector of the support component and the mechanical response vector of the medium corresponding to the current node are used as output items. The theoretical transfer function of the support component and the theoretical transfer function of the medium are established respectively in combination with the load transfer coefficient and constraint stiffness characteristics of the current node.

6. The intelligent monitoring test method for foundation pits according to claim 5, characterized in that, The process of establishing the theoretical response envelope of the mechanical response of the support component and the medium under normal conditions is as follows: Based on the theoretical transfer function at each constraint node, the theoretical mechanical response parameters of the support component and the theoretical mechanical response parameters of the medium at each sampling time under normal conditions are calculated, and the theoretical mechanical response parameter sequences of the support component and the medium are formed respectively. Statistical analysis was performed on the two theoretical mechanical response parameter sequences corresponding to each constraint node. The maximum and minimum values ​​in the theoretical mechanical response parameter sequences of the support components were taken to construct the theoretical response envelope of the support components at each constraint node. The maximum and minimum values ​​in the theoretical mechanical response parameter sequences of the medium were taken to construct the theoretical response envelope of the medium at each constraint node. The theoretical response envelopes corresponding to each constraint node are combined in the order of the nodes to form the overall theoretical response envelopes of the support component and the medium.

7. The intelligent monitoring test method for foundation pits according to claim 6, characterized in that, The process of determining the support component response deviation and the medium mechanical response deviation is as follows: Obtain the measured response vector of the support component and the measured response vector of the medium mechanics of each constraint node in the support component-medium coupling response feature matrix at each sampling time, and compare them with the corresponding overall theoretical response envelope. Determine whether each component of the measured response vector of the support component and the measured response vector of the medium mechanics are within the range defined by the corresponding overall theoretical response envelope; If all components are within their respective ranges, the corresponding response deviation is recorded as zero. If there are components that exceed the range of the corresponding overall theoretical response envelope, calculate the difference between each out-of-limit component and the corresponding envelope boundary value, and sum the differences of each out-of-limit component as the corresponding support component response deviation or medium mechanical response deviation.

8. The intelligent monitoring test method for foundation pits according to claim 7, characterized in that, The process for determining the cause of the anomaly is as follows: If only the support component response deviation is greater than zero, and the medium mechanical response deviation is equal to zero, then the cause of the abnormality is determined to be a problem with the support component. If only the deviation of the medium's mechanical response is greater than zero, and the deviation of the support component's response is equal to zero, then the cause of the anomaly is determined to be a problem of medium change. If both are greater than zero, the cause of the anomaly is determined to be a failure of the coupling between the support component and the medium.

9. A smart monitoring and testing device for foundation pits, characterized in that, include: The data acquisition module obtains the mechanical response parameters of the support components and the mechanical response parameters of the medium, and constructs a time-aligned multi-physical quantity monitoring sequence. The path feature module, based on the spatial geometric relationship between the foundation pit support structure and the medium, establishes the mechanical transfer path and extracts the load transfer coefficient and constraint stiffness characteristics of each constraint node. The process is as follows: The mechanical response parameters of the support components include the strain and displacement values ​​of the support components, and the mechanical response parameters of the medium include the soil pressure and deep horizontal displacement values ​​of the corresponding medium. The above parameters are matched in time sequence. Calculate the ratio of the strain value of the support member to the soil pressure value at each constraint node at the same time, and take the median of the ratios at multiple times as the load transfer coefficient. Calculate the relative displacement difference between the support member displacement value and the deep horizontal displacement value of the medium at each constraint node at the same moment, and determine the interaction force between the support member and the medium based on the node bending moment and distributed reaction force intensity obtained from the strain value of the support member. A force-displacement relationship curve is constructed using the interaction force and the relative displacement difference. The curvature of the force-displacement relationship curve is calculated, and the relative displacement difference corresponding to the maximum curvature value is extracted as the inflection point displacement. Divide the intervals by using the inflection point displacement as the boundary, calculate the average value of the instantaneous stiffness value in each interval, and obtain the corresponding constraint stiffness characteristics; The matrix construction module integrates multi-physical quantity monitoring sequences, load transfer coefficients, and constraint stiffness characteristics to construct a support component-medium coupling response characteristic matrix. The envelope construction module determines the theoretical transfer function at each constraint node based on the mechanical transmission path, and constructs the overall theoretical response envelope of the mechanical response of the support and the medium under normal conditions. The deviation decomposition module obtains the measured response vectors of each constraint node in the support-medium coupling response feature matrix at each sampling time and compares them with the corresponding overall theoretical response envelope to determine the support response deviation and the medium mechanical response deviation. The anomaly diagnosis module determines the cause of the anomaly based on the deviation of the support component response and the deviation of the medium mechanical response, whether it is a problem with the support component, a problem with the medium change, or a problem with the coupling failure between the support component and the medium.

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