Non-limit state earth pressure calculation method based on displacement monitoring

Abstract

The application discloses a non-limit state soil pressure calculation method based on displacement monitoring and relates to the field of soil pressure calculation.The non-limit state soil pressure calculation method based on displacement monitoring comprises the following steps: S1, data is acquired, and coefficients and calculation standards are preset; S2, displacement sensors are arranged according to arrangement rules, and effective displacement monitoring data is obtained by combining collected data; S3, a non-limit state soil pressure coefficient expression is preset, and a displacement soil pressure constitutive model is established; S4, calculation logic is set, and the non-limit state soil pressure is calculated by substituting the model; S5, a threshold value and a calibration rule are preset, the soil pressure is verified and calibrated, and the non-limit state soil pressure is updated; and S6, condition adaptability matching is performed, and a report is generated.The non-limit state soil pressure full-process calculation system is combined with a constitutive model constructed based on an elastic plastic deformation theory of soil to realize engineering adaptability calculation of the non-limit state soil pressure.

Description

Technical Field

[0001] This invention relates to the field of earth pressure calculation, and more particularly to a method for calculating non-limit state earth pressure based on displacement monitoring. Background Technology

[0002] In an era where geotechnical engineering is transforming towards precision and intelligence, and engineering monitoring is being upgraded to data-driven methods, non-limit state earth pressure calculation, as a core technical support for support structure design, construction safety management and risk early warning, has been widely applied in key engineering scenarios such as foundation pit excavation, tunnel excavation, and slope protection. The accuracy of its calculation results, the real-time nature of its data response, and its adaptability to engineering scenarios are directly related to the bearing safety of support structures, the economic efficiency of engineering construction, and the stability of the construction process, making it a core technical bottleneck that urgently needs to be overcome in the digital transformation of geotechnical engineering.

[0003] The deep coupling of displacement monitoring technology with the theory of elastic-plastic deformation of soil, with its ability to capture the dynamic deformation process of soil in real time and accurately invert the state of earth pressure, has shown breakthrough value in the field of non-limit earth pressure calculation. By integrating core technical elements such as multi-source soil parameter analysis, dynamic displacement feature correlation, engineering boundary constraint adaptation, and iterative optimization of calculation parameters, a data-driven integrated calculation system is constructed. This has become a key technical direction to break through the limitations of traditional earth pressure calculation methods and improve the accuracy of engineering adaptation. It is of great significance for reducing redundant design of support structures, shortening construction adjustment cycle, and ensuring the safety of geotechnical engineering.

[0004] However, existing methods for calculating non-limit state earth pressure based on displacement monitoring mostly rely on empirical formulas or single soil parameters for estimation. They lack the ability to correlate core mechanical parameters such as cohesion and internal friction angle with displacement monitoring data, making it difficult to match the differences in soil properties and dynamic deformation patterns across different engineering sites. Furthermore, the placement of monitoring points often depends on general specifications, failing to establish a critical zone guidance mechanism based on the difference between the static earth pressure coefficient and the ultimate earth pressure coefficient. This results in insufficient targeting of monitoring data and low utilization of effective information. Currently, no effective solutions have been proposed to address these technical problems. Summary of the Invention

[0005] To address the problems in related technologies, this invention proposes a non-limit state earth pressure calculation method based on displacement monitoring, in order to overcome the aforementioned technical problems existing in the existing related technologies.

[0006] To achieve the above objectives, the specific technical solution adopted by the present invention is as follows:

[0007] The non-limit state earth pressure calculation method based on displacement monitoring includes the following steps:

[0008] S1. Obtain soil physical and mechanical parameters, earth pressure calculation equipment data and engineering boundary conditions, and preset the calculation standards for static earth pressure coefficient and ultimate earth pressure coefficient;

[0009] S2. Set up the displacement monitoring point layout rules according to the static earth pressure coefficient and the ultimate earth pressure coefficient. Based on the displacement monitoring point layout rules and the earth pressure calculation equipment data, arrange displacement sensors. Collect the horizontal displacement data and vertical displacement data of the structure in real time through the displacement sensors, and combine them to obtain effective displacement monitoring data.

[0010] As a preferred embodiment, the step of setting displacement monitoring point layout rules based on the static earth pressure coefficient and the ultimate earth pressure coefficient, arranging displacement sensors based on the displacement monitoring point layout rules and earth pressure calculation equipment data, and collecting structural horizontal displacement data and structural vertical displacement data in real time through the displacement sensors, and combining them to obtain effective displacement monitoring data includes the following steps:

[0011] S21. Combine the static earth pressure coefficient and the ultimate earth pressure coefficient with the data from the earth pressure calculation equipment to determine the key sections, layout density, and vertical spacing of the monitoring points, and form a rule for the layout of displacement monitoring points.

[0012] As a preferred embodiment, the step of determining the key sections, layout density, and vertical spacing of monitoring points by combining the static earth pressure coefficient and the ultimate earth pressure coefficient with data from earth pressure calculation equipment, and forming a displacement monitoring point layout rule, includes the following steps:

[0013] S211. Calculate the pressure coefficient difference between the static earth pressure coefficient and the ultimate earth pressure coefficient, and set the earth pressure change gradient based on the pressure coefficient difference to locate the potential critical zone of earth pressure.

[0014] S212. Extract the bending resistance data and shear weak section data of the support structure from the data of the earth pressure calculation equipment, and superimpose the potential critical area of ​​earth pressure to lock the key section of the monitoring point;

[0015] S213. Set the equipment layout density at the key section of the monitoring point according to the earth pressure change gradient to obtain the vertical spacing parameters;

[0016] S214. Integrate the key cross-sections of monitoring points, equipment layout density, and vertical spacing parameters to form a rule for the layout of displacement monitoring points.

[0017] S22. Based on the displacement monitoring point layout rules and earth pressure calculation equipment data, select the appropriate displacement sensor type and install and fix the displacement sensor according to the displacement monitoring point layout rules.

[0018] S23. Start the installed and fixed displacement sensor to collect the original data of the horizontal displacement and vertical displacement of the structure in real time, and record the collection time and monitoring point number simultaneously.

[0019] S24. Preprocess the original data of the horizontal displacement and vertical displacement of the structure, and combine the preprocessed original data of the horizontal displacement and vertical displacement of the structure according to the acquisition time and monitoring point number to generate effective displacement monitoring data.

[0020] S3. Based on the theory of elastic plastic deformation of soil, a non-limit state earth pressure coefficient expression is preset, and a displacement earth pressure constitutive model is established by combining soil physical and mechanical parameters and effective displacement monitoring data.

[0021] As a preferred embodiment, the establishment of a displacement earth pressure constitutive model based on the theory of elastic-plastic deformation of soil, a pre-defined expression for the non-limit state earth pressure coefficient, and combined with soil physical and mechanical parameters and effective displacement monitoring data includes the following steps:

[0022] S31. Based on the theory of elastic and plastic deformation of soil, it is clarified that the coefficient range of the non-limit state earth pressure coefficient is between the static earth pressure coefficient and the ultimate earth pressure coefficient.

[0023] S32. Based on the range of coefficient values, a non-limit state earth pressure coefficient expression is preset. The non-limit state earth pressure coefficient expression is based on displacement monitoring data as the core variable, and is associated with the static earth pressure coefficient, the ultimate earth pressure coefficient, and the non-limit state earth pressure coefficient.

[0024] S33. Combining soil physical and mechanical parameters with effective displacement monitoring data, clarify the key pressure parameters in the expression of the earth pressure coefficient in the non-limit state, and integrate the expression of the earth pressure coefficient in the non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement earth pressure constitutive model.

[0025] As a preferred embodiment, the process of combining soil physical and mechanical parameters with effective displacement monitoring data to clarify the key pressure parameters in the expression for the earth pressure coefficient under non-limit state, and then integrating the expression for the earth pressure coefficient under non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement-earth pressure constitutive model includes the following steps:

[0026] S331. Extract the cohesion, internal friction angle and compression modulus from the physical and mechanical parameters of the soil as core index parameters, and simultaneously extract the peak displacement value and stable displacement characteristic value from the effective displacement monitoring data.

[0027] S332. Using the core index parameters, peak displacement value and stable displacement characteristic value as the pressure key parameters, and substituting the pressure key parameters into the expression of the earth pressure coefficient in the non-limit state, the initial pressure values ​​of the pressure key parameters are determined.

[0028] As a preferred embodiment, the method of determining the initial pressure values ​​of key pressure parameters by using core index parameters, peak displacement values, and stable displacement characteristic values, and substituting these key pressure parameters into the expression for the earth pressure coefficient in the non-limit state, includes the following steps:

[0029] S3321. Unit unification processing is performed on the core index parameters, peak displacement values, and stable displacement characteristic values ​​to obtain a standardized parameter set. The correspondence between each variable in the expression of the earth pressure coefficient in the non-limit state and the standardized parameter set is clarified, and a parameter variable mapping table is established.

[0030] S3322. According to the parameter variable mapping table, substitute each parameter in the standardized parameter set into the expression of the earth pressure coefficient in the non-limit state to obtain the preliminary values ​​of each pressure key parameter, and classify and organize the preliminary values ​​of each pressure key parameter to form a set of initial pressure values.

[0031] S333. Compare the initial pressure value with the range of coefficient values, and correct the initial pressure value based on the comparison results to obtain the key pressure parameters.

[0032] S334. Substitute the key pressure parameters into the expression for the earth pressure coefficient in the non-limit state, and establish a correlation mapping with the soil physical and mechanical parameters and effective displacement monitoring data to form a displacement earth pressure constitutive model.

[0033] S4. Set up the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model according to the engineering boundary conditions, and substitute the effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure.

[0034] As a preferred embodiment, the step of setting the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model according to the engineering boundary conditions, and substituting the effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure includes the following steps:

[0035] S41. Extract the calculation engineering depth, groundwater depth and support structure constraint parameters from the engineering boundary conditions, and clarify the boundary constraint conditions for earth pressure calculation.

[0036] S42. Combine the boundary constraints with the displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transmission calculation logic of the non-ultimate earth pressure, and integrate them to obtain the non-ultimate earth pressure calculation logic.

[0037] As a preferred embodiment, the steps of combining boundary constraints with a displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transfer calculation logic of non-ultimate earth pressure, and integrating them to obtain the non-ultimate earth pressure calculation logic, include the following:

[0038] S421. Analyze the influence weights of earth pressure on the engineering depth, groundwater depth and support structure constraint parameters in the boundary constraint conditions, and clarify the earth pressure correlation between the engineering depth, groundwater depth and support structure constraint parameters.

[0039] S422. Combine the influence weight of earth pressure and the correlation of earth pressure with the displacement earth pressure constitutive model, and establish the vertical distribution logic of non-ultimate earth pressure by associating the physical and mechanical parameters of the soil with the calculation engineering depth as the vertical reference.

[0040] S423. Based on the constraint parameters of the support structure, establish the horizontal transmission calculation logic of non-ultimate earth pressure, and clarify the transmission correlation rules between transmission efficiency and constraint strength.

[0041] S424. Verify the coupling compatibility between the vertical distribution logic and the horizontal transmission logic according to the transmission association rules, eliminate logical conflict points, and integrate them to form the non-limit earth pressure calculation logic.

[0042] S43. Extract the monitoring point number and calculation depth from the effective displacement monitoring data, and substitute the monitoring point number and calculation depth into the displacement earth pressure constitutive model according to the non-ultimate earth pressure calculation logic to calculate the non-ultimate earth pressure value.

[0043] S44. Perform compliance verification on the non-limit earth pressure values, and adjust the output of the non-limit earth pressure values ​​according to the compliance verification results.

[0044] S5. Preset displacement change rate threshold and parameter calibration rules, verify and calibrate the non-limit state earth pressure based on the displacement change rate threshold and parameter calibration rules, and update the non-limit state earth pressure according to the verification and calibration results.

[0045] As a preferred embodiment, the preset displacement change rate threshold and parameter calibration rules, based on which the non-limit state earth pressure is verified and calibrated, and the non-limit state earth pressure is updated according to the verification and calibration results, include the following steps:

[0046] S51. Based on the physical and mechanical parameters of the soil, the data from the soil pressure calculation equipment, and the engineering boundary conditions, preset the displacement change rate threshold and parameter calibration rules.

[0047] S52. The effective displacement monitoring data is divided into time-series segments. The real-time displacement change rate is calculated for the effective displacement monitoring data after time-series segmentation. The real-time displacement change rate is compared with the displacement change rate threshold. The rationality of the pressure of the non-limit state earth pressure is judged based on the comparison results.

[0048] As a preferred embodiment, the step of segmenting the effective displacement monitoring data into time series, calculating the real-time displacement change rate of the segmented effective displacement monitoring data, comparing the real-time displacement change rate with a displacement change rate threshold, and determining the rationality of the non-limit state earth pressure based on the comparison results includes the following steps:

[0049] S521. Based on the time interval of the effective displacement monitoring data collection and the engineering construction stage, set the time sequence segmentation rules, and divide the effective displacement monitoring data into segments according to the time sequence segmentation rules.

[0050] S522. For the effective displacement monitoring data in each segment, group them according to the monitoring point number, and calculate the real-time displacement change rate set by dividing the displacement difference between adjacent time periods by the time interval.

[0051] S523. Compare the real-time displacement change rate in the real-time displacement change rate set with the displacement change rate threshold one by one, and determine the rationality of the pressure of the non-limit state earth pressure based on the comparison results.

[0052] S53. Based on the rationality of pressure and parameter calibration rules, verify the key pressure parameters of the calibrated displacement earth pressure constitutive model and update the non-limit state earth pressure.

[0053] S6. Perform condition adaptation matching between the updated non-limit state earth pressure and the engineering boundary conditions, and generate a non-limit state earth pressure calculation report.

[0054] The beneficial effects of this invention are as follows:

[0055] 1. This invention utilizes a displacement monitoring data-driven full-process calculation system for non-limit state earth pressure. It combines constitutive model construction supported by soil elastic-plastic deformation theory, optimization of calculation logic coupled with multi-dimensional engineering boundary conditions, and a closed-loop verification and calibration mechanism driven by displacement change rate thresholds. Coupled with a hierarchical and precise displacement monitoring point layout scheme and a full-chain processing strategy of parameter standardization mapping correction, it achieves accurate, efficient, and engineering-adaptable calculation of non-limit state earth pressure. This avoids the core pain points of blind monitoring point layout, static constitutive model parameters, fragmented calculation logic, and lack of closed-loop result verification. It also reduces redundancy or insufficient safety reserves in support structure design and construction risks caused by earth pressure calculation errors. This approach addresses the potential risks of increased risk and higher maintenance costs. It also addresses the issues of weak targeting and insufficient data collection effectiveness by using critical zone positioning guided by the difference between the static earth pressure coefficient and the ultimate earth pressure coefficient, locking key sections of monitoring points adapted to the mechanical properties of the support structure, and optimizing the layout density by matching the earth pressure change gradient. This enhances the core value and utilization rate of displacement monitoring data. Furthermore, it leverages the deep integration of core soil parameters such as cohesion and internal friction angle with peak displacement and stable displacement characteristic values. Combined with standardized processing such as unit unification, outlier data removal, and precise mapping of parameter variables, it ensures the scientific validity and reliability of the initial parameter values ​​of the constitutive model, avoiding the defects of subjective parameter setting and invalidated data interference.

[0056] 2. This invention analyzes the influence weights of engineering depth, groundwater depth, and support structure constraint parameters to construct a coupled calculation logic for the vertical distribution and horizontal transmission of non-limit earth pressure. This solves the problems of neglecting the synergistic effects of multiple boundary conditions and the lack of verification of logical conflicts, enhancing the adaptability of calculation results to actual engineering scenarios. By using time-series segmentation rules adapted to the collection time interval and construction stage, the rate of change calculation of displacement difference method between adjacent time periods, and the rationality judgment of threshold comparison one by one, dynamic real-time verification of earth pressure results is achieved. Combined with constitutive model iterative optimization driven by parameter calibration rules, a closed-loop process of calculation, verification, calibration, and update is formed, avoiding the lag and inaccuracy of results caused by static calculation. At the same time, through technical collaboration and optimization of all links in the process, the accuracy, real-time performance, and reliability of non-limit state earth pressure calculation are improved, ensuring the economy and safety of support structure design, shortening the engineering design and construction response cycle, reducing the cost of repeated calculations and monitoring, and enhancing the engineering operability and scenario scalability of the method. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a flowchart of a non-limit state earth pressure calculation method based on displacement monitoring according to an embodiment of the present invention. Detailed Implementation

[0059] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0060] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0061] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, the non-limit state earth pressure calculation method based on displacement monitoring according to an embodiment of the present invention includes the following steps:

[0062] S1. Obtain soil physical and mechanical parameters, earth pressure calculation equipment data and engineering boundary conditions, and preset the calculation standards for static earth pressure coefficient and ultimate earth pressure coefficient;

[0063] Specifically, the acquisition of relevant data and the calculation of preset coefficients are completed through multi-dimensional collaboration. The physical and mechanical parameters of the soil need to be combined with engineering surveys. Uncirculated soil samples are obtained through drilling and sampling. Core indicators such as cohesion, internal friction angle, and compression modulus are measured through indoor tests. At the same time, regional soil characteristic data from the site geological survey report are collected as a supplement.

[0064] The data for earth pressure calculation equipment needs to be analyzed, including the range, accuracy, and sampling frequency of the displacement sensors, data acquisition instruments, and other equipment used. At the same time, the working condition data such as the equipment installation location and layout density should be recorded. The engineering boundary conditions are extracted from the design documents and on-site surveys, including the engineering depth, groundwater depth, support structure type, and constraint characteristics. When setting the calculation standards for static and ultimate earth pressure coefficients, industry standards such as the Code for Design of Building Foundations should be referenced, and the soil type and engineering type should be combined to clarify that the static earth pressure coefficient is determined by empirical formulas or in-situ tests, and the ultimate earth pressure coefficient is selected according to Rankine or Coulomb earth pressure theory to ensure that the standards are compatible with the actual engineering and soil properties.

[0065] S2. Set up the displacement monitoring point layout rules according to the static earth pressure coefficient and the ultimate earth pressure coefficient. Based on the displacement monitoring point layout rules and the earth pressure calculation equipment data, arrange displacement sensors. Collect the horizontal displacement data and vertical displacement data of the structure in real time through the displacement sensors, and combine them to obtain effective displacement monitoring data.

[0066] As a preferred embodiment, the step of setting displacement monitoring point layout rules based on the static earth pressure coefficient and the ultimate earth pressure coefficient, arranging displacement sensors based on the displacement monitoring point layout rules and earth pressure calculation equipment data, and collecting structural horizontal displacement data and structural vertical displacement data in real time through the displacement sensors, and combining them to obtain effective displacement monitoring data includes the following steps:

[0067] S21. Combine the static earth pressure coefficient and the ultimate earth pressure coefficient with the data from the earth pressure calculation equipment to determine the key sections, layout density, and vertical spacing of the monitoring points, and form a rule for the layout of displacement monitoring points.

[0068] As a preferred embodiment, the step of determining the key sections, layout density, and vertical spacing of monitoring points by combining the static earth pressure coefficient and the ultimate earth pressure coefficient with data from earth pressure calculation equipment, and forming a displacement monitoring point layout rule, includes the following steps:

[0069] S211. Calculate the pressure coefficient difference between the static earth pressure coefficient and the ultimate earth pressure coefficient, and set the earth pressure change gradient based on the pressure coefficient difference to locate the potential critical zone of earth pressure.

[0070] Specifically, based on engineering specifications and soil properties, the static earth pressure coefficient is first determined through empirical formulas and in-situ tests. The ultimate earth pressure coefficient is then calculated according to Rankine or Coulomb earth pressure theory. The absolute value of the difference between the two is obtained. Subsequently, the earth pressure change gradient levels are divided according to the magnitude of the difference: a difference > 0.3 is set as a high gradient (0.8-1.2 kPa / m), 0.1-0.3 is set as a medium gradient (0.4-0.8 kPa / m), and < 0.1 is set as a low gradient (0.1-0.4 kPa / m). The standard for the rate of change of earth pressure corresponding to each gradient is clarified. Then, combined with the stress analysis of the support structure, the high and medium gradient regions are superimposed with the weak sections of the structure in terms of bending and shear resistance (such as the peak bending moment section). The gradient abrupt change points and the areas of concentrated difference are marked to form the potential critical area of ​​earth pressure.

[0071] S212. Extract the bending resistance data and shear weak section data of the support structure from the data of the earth pressure calculation equipment, and superimpose the potential critical area of ​​earth pressure to lock the key section of the monitoring point;

[0072] Specifically, data is first extracted from the structural monitoring system associated with the earth pressure calculation equipment, the support structure design documents, and the finite element calculation report. For bending data, the real-time monitoring bending moment value and the design bending moment limit value of each section are taken as the main data. For shear data, the real-time shear force value and shear bearing capacity parameters of the section are extracted.

[0073] By comparing real-time values ​​with ultimate values, sections with a ratio exceeding 0.7 are marked as shear-weak sections, and sections with bending moments close to the ultimate values ​​are marked as bending-weak sections. Then, the marked weak sections are superimposed with the potential critical areas of earth pressure (high gradient and gradient abrupt change areas), and the overlapping areas of the two are prioritized. Special attention is paid to sections where the peak value of earth pressure gradient coincides with the peak value of bending moment and shear force. Finally, these superimposed core areas are identified as key sections of monitoring points to ensure that monitoring focuses on areas with concentrated stress risks.

[0074] S213. Set the equipment layout density at the key section of the monitoring point according to the earth pressure change gradient to obtain the vertical spacing parameters;

[0075] Specifically, first clarify the corresponding standards for gradient and density. In high gradient areas (difference > 0.3), due to the drastic fluctuations in soil pressure, one sensor is deployed every 0.5-1m; in medium gradient areas (0.1-0.3), one sensor is deployed every 1-2m; and in low gradient areas (< 0.1), one sensor is deployed every 2-3m. At the same time, considering the length of key sections and structural characteristics, if there are stress concentration points such as corners and joints in the section, the density of the foundation is increased by 50%.

[0076] Subsequently, the planning was carried out in segments according to the principle of "gradient priority plus structural adaptation". The total height of the key section was divided by the number of sensors in the corresponding area, and the redundant space for equipment installation was deducted to calculate the vertical spacing parameters of each segment. This ensured that the spacing in high-risk areas was small and the data coverage was complete, while the spacing in low-risk areas was reasonable and the cost was reduced.

[0077] S214. Integrate the key cross-sections of monitoring points, equipment layout density, and vertical spacing parameters to form a rule for the layout of displacement monitoring points.

[0078] Specifically, we first systematically sort out the specific location, range and structural characteristics of the key sections of the monitoring points, match the earth pressure gradient level of each section, and clarify the equipment layout density and vertical spacing standards corresponding to the high, medium and low gradient zones.

[0079] Following the logic of "section segmentation - density adaptation - spacing implementation", the key sections are divided into gradient zones. The high gradient zone strictly adheres to a spacing of 0.5-1m, the medium gradient zone uses a spacing of 1-2m, and the low gradient zone is planned with a spacing of 2-3m. Special parts such as structural corners and joints have additional densification on the foundation spacing. At the same time, the sensor installation height, fixing method, and requirements for avoiding embedded parts are marked, forming a standardized layout rule that includes "key section number, corresponding gradient level, layout density, vertical spacing, and installation constraints", ensuring that the rule is both targeted and executable.

[0080] S22. Based on the displacement monitoring point layout rules and earth pressure calculation equipment data, select the appropriate displacement sensor type and install and fix the displacement sensor according to the displacement monitoring point layout rules.

[0081] Specifically, first extract key information based on the displacement monitoring point layout rules. High-gradient critical areas require high-precision sensors with a accuracy of ±0.01mm, while medium- and low-gradient areas can use models with an accuracy of ±0.1mm. Outdoor or humid environments require IP67 or higher protection levels. Combined with data from soil pressure calculation equipment, ensure that the sensor range covers more than 1.2 times the estimated displacement, and that the sampling frequency is compatible with the data acquisition instrument (10-50Hz).

[0082] Then, the installation points are located according to the layout rules. The installation surface of the cross section is cleaned and leveled. High-risk sections are rigidly fixed with bolts, while ordinary areas are fixed with brackets and clips to ensure that the sensor probe is vertically aligned with the monitoring surface and has no rigid contact with the structure. After installation, the spacing and the matching degree of the key cross section are checked. The verticality is calibrated with a level. The data line is connected and waterproof protection is provided. After the fixing is completed, a pre-collection test is carried out to ensure stable data transmission.

[0083] S23. Start the installed and fixed displacement sensor to collect the original data of the horizontal displacement and vertical displacement of the structure in real time, and record the collection time and monitoring point number simultaneously.

[0084] Specifically, first check the connection status of the sensor power line, data transmission line, and data acquisition instrument to ensure that the interface is secure and the power supply is stable. Confirm that the sensor communication is normal through the data acquisition system's debugging mode. Then, configure the parameters in the data acquisition software, enter the number of each monitoring point and bind it to the corresponding sensor, set the sampling frequency (matching the device's 10-50Hz standard), and check the "synchronous acquisition of horizontal and vertical displacement" and "automatic generation of timestamps" functions. The time is accurate to milliseconds. After starting, the sensor captures the structural displacement in real time, and the software automatically associates and stores the horizontal and vertical raw data with the acquisition time and monitoring point number. After the initial 10 minutes of acquisition, check the data integrity. If there are incorrect numbers or time offsets, recalibrate the association mapping between the device and the system to ensure that each set of raw data clearly corresponds to the monitoring position and acquisition time, ensuring the accuracy of subsequent data processing.

[0085] S24. Preprocess the original data of the horizontal displacement and vertical displacement of the structure, and combine the preprocessed original data of the horizontal displacement and vertical displacement of the structure according to the acquisition time and monitoring point number to generate effective displacement monitoring data.

[0086] Specifically, the 3σ criterion is first used to remove outliers (data exceeding the mean ± 3 standard deviations) from the horizontal and vertical displacement data. Then, the high-frequency noise is smoothed using the 5-point moving average method. For a small number of missing data, linear interpolation is used to fill in the gaps. Subsequently, based on the acquisition timestamp, the preprocessed horizontal and vertical displacement data are sorted in ascending order by time and simultaneously grouped by monitoring point number to establish a four-dimensional correlation table of "number-time-horizontal displacement-vertical displacement". The integrity of the two types of data with the same number and the same timestamp is verified by a data matching algorithm, and invalid data with mismatched time or number are removed. Finally, structured and effective displacement monitoring data is generated to ensure that the data is both accurate and correlated.

[0087] S3. Based on the theory of elastic plastic deformation of soil, a non-limit state earth pressure coefficient expression is preset, and a displacement earth pressure constitutive model is established by combining soil physical and mechanical parameters and effective displacement monitoring data.

[0088] As a preferred embodiment, the establishment of a displacement earth pressure constitutive model based on the theory of elastic-plastic deformation of soil, a pre-defined expression for the non-limit state earth pressure coefficient, and combined with soil physical and mechanical parameters and effective displacement monitoring data includes the following steps:

[0089] S31. Based on the theory of elastic and plastic deformation of soil, it is clarified that the coefficient range of the non-limit state earth pressure coefficient is between the static earth pressure coefficient and the ultimate earth pressure coefficient.

[0090] Specifically, based on the theory of elastic-plastic deformation of soil, the range of coefficient values ​​is clearly defined. The core is to anchor the relationship between soil deformation and soil pressure. After the soil is subjected to force, it first undergoes elastic deformation. At this time, the soil pressure is in a static state (corresponding to the static soil pressure coefficient). As the load increases, the soil enters the elastic-plastic transition stage. Finally, when plastic failure is reached, the soil pressure reaches its extreme value (corresponding to the ultimate soil pressure coefficient).

[0091] In the operation, the static earth pressure coefficient is first determined according to the specifications, and the ultimate earth pressure coefficient is calculated according to Rankine-Coulomb theory. Then, combined with the core conclusion of the theory that "the non-limit state is the transition stage from elastic deformation to plastic failure", it is clear that the soil deformation in this stage has not reached the critical value of failure, and the earth pressure is between the static value and the ultimate value. Therefore, the range of the non-limit state earth pressure coefficient must fall between the two. At the same time, it can be verified by combining displacement monitoring data to ensure that the range is consistent with the actual deformation stage of the soil.

[0092] S32. Based on the range of coefficient values, a non-limit state earth pressure coefficient expression is preset. The non-limit state earth pressure coefficient expression is based on displacement monitoring data as the core variable, and is associated with the static earth pressure coefficient, the ultimate earth pressure coefficient, and the non-limit state earth pressure coefficient.

[0093] Specifically, the basic framework of the expression is first clarified. The static earth pressure coefficient (K0) is used as the lower limit and the ultimate earth pressure coefficient (Kf) is used as the upper limit. A dynamic model of "non-limit coefficient (K) = K0 + f(Δ) × (Kf - K0)" is constructed, where f(Δ) is the correlation function of displacement monitoring data. The normalized displacement value (Δ, i.e., the ratio of actual displacement to ultimate displacement) in the effective displacement monitoring data is selected as the core variable. By fitting the soil deformation curve, the form of f(Δ) is determined to be a linear function in the elastic stage and an exponential function in the elastoplastic stage. At the same time, the parameters of the calibration function are substituted into the engineering measured data to ensure that K = K0 when Δ = 0 (no deformation) and K = Kf when Δ = 1 (reaching the ultimate deformation), so that the expression strictly falls within the value range, realizing the dynamic correlation between the non-limit coefficient and displacement and the organic coupling of the three types of coefficients.

[0094] S33. Combining soil physical and mechanical parameters with effective displacement monitoring data, clarify the key pressure parameters in the expression of the earth pressure coefficient in the non-limit state, and integrate the expression of the earth pressure coefficient in the non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement earth pressure constitutive model.

[0095] As a preferred embodiment, the process of combining soil physical and mechanical parameters with effective displacement monitoring data to clarify the key pressure parameters in the expression for the earth pressure coefficient under non-limit state, and then integrating the expression for the earth pressure coefficient under non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement-earth pressure constitutive model includes the following steps:

[0096] S331. Extract the cohesion, internal friction angle and compression modulus from the physical and mechanical parameters of the soil as core index parameters, and simultaneously extract the peak displacement value and stable displacement characteristic value from the effective displacement monitoring data.

[0097] Specifically, the physical and mechanical parameters of the soil are extracted from the engineering survey results. Data from undisturbed soil samples obtained through drilling and laboratory testing are prioritized. Cohesion is determined by measuring the peak shear stress through direct shear tests, while the internal friction angle is simultaneously obtained by fitting the test curve. The compression modulus is calculated based on the ep curve of the consolidation test. At the same time, the average parameters of the same soil layer in the site geological report are supplemented as verification. Abnormal data deviating from the average by more than 20% are removed. When extracting effective displacement monitoring data, the maximum horizontal / vertical displacement of each point within the monitoring period is selected as the peak displacement value through data processing software. The standard is that the displacement change is ≤0.02mm for three consecutive sampling periods to determine the stable displacement characteristic value. Finally, an association table is established according to the monitoring point number to match the corresponding core soil parameters with the displacement characteristic value one by one, ensuring that the data source is traceable and the correspondence is clear.

[0098] S332. Using the core index parameters, peak displacement value and stable displacement characteristic value as the pressure key parameters, and substituting the pressure key parameters into the expression of the earth pressure coefficient in the non-limit state, the initial pressure values ​​of the pressure key parameters are determined.

[0099] As a preferred embodiment, the method of determining the initial pressure values ​​of key pressure parameters by using core index parameters, peak displacement values, and stable displacement characteristic values, and substituting these key pressure parameters into the expression for the earth pressure coefficient in the non-limit state, includes the following steps:

[0100] S3321. Unit unification processing is performed on the core index parameters, peak displacement values, and stable displacement characteristic values ​​to obtain a standardized parameter set. The correspondence between each variable in the expression of the earth pressure coefficient in the non-limit state and the standardized parameter set is clarified, and a parameter variable mapping table is established.

[0101] Specifically, first, sort out the original units of the core indicator parameters and displacement characteristic values, and uniformly convert cohesion and compressive modulus to kPa (e.g., MPa to kPa requires ×1000), retain internal friction angle, and convert peak and stable displacement values ​​to m (e.g., mm to m requires ÷1000). Complete the unification through unit conversion formula, and then use the 3σ criterion to remove outliers to form a standardized parameter set.

[0102] Subsequently, the expression structure for the non-limit state earth pressure coefficient was deconstructed, and the definitions of each variable were clarified. The standardized cohesion was assigned to c, the internal friction angle to φ, the compression modulus to Es, the peak displacement to Δmax, and the stable displacement characteristic value to Δs, with the standardized units of each variable simultaneously labeled. Finally, a parameter variable mapping table was established, listing four columns: parameter name, original unit, standardized unit, and the corresponding variable in the expression. This ensures a one-to-one correspondence between parameters and variables, laying the foundation for subsequent substitution calculations.

[0103] S3322. According to the parameter variable mapping table, substitute each parameter in the standardized parameter set into the expression of the earth pressure coefficient in the non-limit state to obtain the preliminary values ​​of each pressure key parameter, and classify and organize the preliminary values ​​of each pressure key parameter to form a set of initial pressure values.

[0104] Specifically, the operation begins by referring to the parameter variable mapping table to accurately match the core indicators such as cohesion and internal friction angle in the standardized parameter set, as well as the peak value and stable displacement characteristic value, with the corresponding variables in the expression for the earth pressure coefficient in the non-limit state, avoiding parameter misalignment. Then, the calculation is performed step by step according to the expression operation rules. First, the basic terms related to soil mechanics parameters are calculated, and then the displacement characteristic value correction term is incorporated. The preliminary values ​​of each key pressure parameter are obtained through algebraic operations. Each step of the calculation process and intermediate results are recorded simultaneously. After the calculation is completed, the preliminary values ​​are classified according to parameter type (soil mechanics type, displacement related type), and the monitoring point number, parameter name, and standardized unit corresponding to each value are labeled. Calculation error data is eliminated, and finally, a structured set of initial pressure values ​​is formed to ensure that the values ​​are traceable and clearly classified, providing a basis for subsequent correction steps.

[0105] S333. Compare the initial pressure value with the range of coefficient values, and correct the initial pressure value based on the comparison results to obtain the key pressure parameters.

[0106] Specifically, first, define the range of values ​​for the non-ultimate earth pressure coefficient (K0 as the lower limit and Kf as the upper limit). Then, compare each initial pressure value with the upper and lower limits of the range. If the initial value falls within [K0, Kf], it is directly retained as a candidate value. If it is lower than K0, it is corrected using the stable displacement characteristic value (Δs). When Δs is small, the average of K0 and the initial value is used; when Δs is close to the ultimate displacement, it is adjusted upwards to within the range. If it is higher than Kf, the peak displacement value (Δmax) is referenced for correction. When Δmax has not reached the limit, it is adjusted downwards to near Kf; when Δmax is close to the limit, Kf is used. After correction, the values ​​are verified using core parameters such as soil cohesion and internal friction angle to ensure they match the elastoplastic deformation stage of the soil. Finally, values ​​that meet the range requirements and are consistent with the actual engineering situation are selected as key pressure parameters.

[0107] S334. Substitute the key pressure parameters into the expression for the earth pressure coefficient in the non-limit state, and establish a correlation mapping with the soil physical and mechanical parameters and effective displacement monitoring data to form a displacement earth pressure constitutive model.

[0108] Specifically, the corrected key pressure parameters are first accurately substituted into the expression for the earth pressure coefficient in the non-limit state, and the corresponding variables are replaced to complete the basic calculations. The functional relationship between the coefficients and the displacement monitoring data is then determined. Subsequently, a correlation system of "key pressure parameters - soil physical and mechanical parameters - effective displacement monitoring data" is established. Parameters such as cohesion and internal friction angle are bound to the strength correction term in the expression, and the peak and stable displacement values ​​are associated with the displacement correction term. The weight of each data in the model is clarified. Based on this, a displacement earth pressure constitutive model is formed. The model needs to include an input layer (soil parameters, displacement data), a calculation layer (coefficient expression), and an output layer (non-limit earth pressure value). Finally, the model is verified by engineering measured earth pressure data, and the parameter correlation weights are fine-tuned to ensure that the deviation between the model output and the actual working conditions is ≤5%, thereby improving its reliability and engineering adaptability.

[0109] S4. Set up the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model according to the engineering boundary conditions, and substitute the effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure.

[0110] As a preferred embodiment, the step of setting the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model according to the engineering boundary conditions, and substituting the effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure includes the following steps:

[0111] S41. Extract the calculation engineering depth, groundwater depth and support structure constraint parameters from the engineering boundary conditions, and clarify the boundary constraint conditions for earth pressure calculation.

[0112] Specifically, the engineering depth is extracted from the engineering design drawings, using key elevations such as the bottom of the foundation pit and the top and bottom slabs of the tunnel as references, and combining them with the ground elevation to calculate the actual depth. The groundwater depth is obtained through on-site water level observation wells or water level records during drilling, while simultaneously referring to the regional groundwater level data in the geological survey report, marking the dynamic range of change. The constraint parameters of the support structure are extracted from the design documents and construction records, including the cross-sectional dimensions of the piles or continuous walls, concrete strength, anchorage length of the anchors / supports, prestressing force, etc. When clarifying the boundary constraint conditions, the calculated engineering depth is used as the vertical boundary of the earth pressure calculation. The groundwater depth defines the boundary between separate and combined calculations of soil and water. The constraint parameters of the support structure are converted into mechanical constraints such as lateral displacement limits and bearing capacity thresholds. At the same time, the boundary values ​​of the soil lateral pressure coefficient are clarified with reference to the specifications to ensure that the constraint conditions conform to the actual engineering situation.

[0113] S42. Combine the boundary constraints with the displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transmission calculation logic of the non-ultimate earth pressure, and integrate them to obtain the non-ultimate earth pressure calculation logic.

[0114] As a preferred embodiment, the steps of combining boundary constraints with a displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transfer calculation logic of non-ultimate earth pressure, and integrating them to obtain the non-ultimate earth pressure calculation logic, include the following:

[0115] S421. Analyze the influence weights of earth pressure on the engineering depth, groundwater depth and support structure constraint parameters in the boundary constraint conditions, and clarify the earth pressure correlation between the engineering depth, groundwater depth and support structure constraint parameters.

[0116] Specifically, the analytic hierarchy process (AHP) combined with numerical simulation was used, with the engineering depth, groundwater depth, and support structure constraint parameters as evaluation indicators. The impact of changes in each parameter on earth pressure was compared to determine the weights. Engineering depth directly determines the soil's self-weight stress, accounting for 30%-40% of the weight; groundwater depth is related to the superposition effect of water and soil pressure, accounting for 25%-35% of the weight; and support structure constraint parameters affect lateral pressure transmission, accounting for 25%-30% of the weight. In terms of correlation, engineering depth and earth pressure are positively correlated; for every 1m increase in depth, earth pressure increases by approximately 10-15 kPa.

[0117] When the groundwater depth is within the engineering depth, the shallower the depth, the greater the earth pressure. When the depth exceeds the engineering depth, the impact weakens. The stronger the constraint of the support structure (such as a large prestressing force of the anchor bolts), the more obvious the earth pressure attenuation. The constraint parameters are negatively correlated with the earth pressure, and finally a quantitative correlation model between each parameter and the earth pressure is formed.

[0118] S422. Combine the influence weight of earth pressure and the correlation of earth pressure with the displacement earth pressure constitutive model, and establish the vertical distribution logic of non-ultimate earth pressure by associating the physical and mechanical parameters of the soil with the calculation engineering depth as the vertical reference.

[0119] Specifically, the influence weights of earth pressure (30%-40% of engineering depth, 25%-35% of groundwater depth, and 25%-30% of support constraints) and their quantitative correlations are first embedded into the displacement earth pressure constitutive model. The engineering depth is set as the vertical reference axis, and the calculation units are divided into layers of 1-2m.

[0120] For each unit, the soil physical and mechanical parameters (cohesion, internal friction angle, etc.) at the corresponding depth are combined, and the foundation soil pressure is calculated using the positive correlation formula between depth and soil pressure in the model. Then, based on the groundwater depth of the unit (the shallower the depth, the greater the pressure) and the support constraint strength (the stronger the constraint, the weaker the pressure), the foundation value is corrected using a weighting coefficient. At the same time, the displacement monitoring data of each unit are linked, and the model displacement correction item is dynamically adjusted to form a vertical distribution logic of "depth benchmark - layer parameters - weight correction - displacement calibration". This clarifies the variation law of soil pressure at different depths and ensures that the distribution results match the actual stress of the soil.

[0121] S423. Based on the constraint parameters of the support structure, establish the horizontal transmission calculation logic of non-ultimate earth pressure, and clarify the transmission correlation rules between transmission efficiency and constraint strength.

[0122] Specifically, to establish a horizontal transfer calculation logic based on the constraint parameters of the support structure, it is necessary to first quantify the constraint parameters (anchor preload, pile section stiffness, support axial force, etc.) as mechanical indicators, and construct the path logic of "soil lateral pressure - support body bearing capacity - constraint system transfer" with the support structure as the core: according to the direction of horizontal force transfer, first calculate the initial non-ultimate earth pressure of the soil acting on the support body, then calculate the lateral stiffness of the support body in combination with the constraint parameters, and obtain the earth pressure value transferred to the constraint system through the force balance equation, while simultaneously taking into account the friction loss and deformation attenuation during the transfer process.

[0123] The transmission efficiency is positively correlated with the constraint strength: for every 10% increase in constraint strength, the transmission efficiency increases by 5%-8%, especially when the anchor preload reaches 80% of the design value and the pile stiffness is ≥5×10. 4 When the force is kN / m, the transmission efficiency is stable at over 85%. When the constraint strength is less than 50% of the design value, the transmission efficiency drops sharply and local instability is likely to occur. The rationality of the logic needs to be verified through numerical simulation.

[0124] S424. Verify the coupling compatibility between the vertical distribution logic and the horizontal transmission logic according to the transmission association rules, eliminate logical conflict points, and integrate them to form the non-limit earth pressure calculation logic.

[0125] Specifically, the transmission association rules (such as the positive correlation between constraint strength and transmission efficiency) are used as the verification benchmark. Typical calculation units are selected and the vertical distribution logic and horizontal transmission logic are simultaneously substituted. The earth pressure values ​​and mechanical equilibrium states output by the two are compared. If the deviation between the earth pressure value calculated vertically and the force value after horizontal transmission exceeds 10%, or if the constraint is strong but the horizontal transmission efficiency is low, or if the increase in vertical pressure and the decrease in horizontal pressure do not match, then it is determined to be a logical conflict point.

[0126] When eliminating conflicts, priority is given to using the displacement and stress data measured in the engineering as the basis to adjust the depth weight of the vertical distribution or the loss coefficient of the horizontal transmission. If the constraint reaches more than 80% of the design value, the horizontal transmission efficiency is forced to match the increase in vertical pressure. During the final integration, the vertical layering is matched with the horizontal transmission path one by one, and it is clear that the vertical earth pressure of the same unit must meet the balance condition with the horizontal transmission force, forming a closed-loop logic of "vertical layering calculation - horizontal transmission verification - data anchoring correction" to ensure that there are no conflicts in the coupling.

[0127] S43. Extract the monitoring point number and calculation depth from the effective displacement monitoring data, and substitute the monitoring point number and calculation depth into the displacement earth pressure constitutive model according to the non-ultimate earth pressure calculation logic to calculate the non-ultimate earth pressure value.

[0128] Specifically, from the structured effective displacement monitoring data, the data is filtered and extracted according to the "monitoring point number" field, and the calculation depth of the corresponding monitoring point is synchronously associated. This depth needs to be determined by combining the engineering design drawings and the difference between the installation elevation of the monitoring point and the site reference surface to ensure that it is consistent with the vertical layering depth of the non-ultimate earth pressure calculation logic. Data with missing numbers or depths are removed to form a "monitoring point number - calculation depth" association pair.

[0129] Subsequently, based on the calculation logic, the soil physical and mechanical parameters (cohesion, internal friction angle, etc.) of the associated pair and corresponding depth are substituted into the displacement earth pressure constitutive model: first, the foundation earth pressure at this depth is calculated through vertical distribution logic, then corrected according to the horizontal transmission rules, and finally the non-ultimate earth pressure value is output. After calculation, the results are verified to ensure that the earth pressure value with the same number matches the displacement data and constraint parameters, thereby improving the reliability of the results.

[0130] S44. Perform compliance verification on the non-limit earth pressure values, and adjust the output of the non-limit earth pressure values ​​according to the compliance verification results.

[0131] Specifically, first, compare the values ​​with specifications such as the Technical Specification for Foundation Pit Support to verify whether they fall within the theoretical range for the corresponding soil type (e.g., the non-ultimate earth pressure for cohesive soil should be 15-50 kPa). At the same time, check whether they conform to the logical rule of "vertical pressure increases with depth and horizontal pressure decreases with increasing constraint". Then, compare the values ​​with the measured earth pressure data at the same monitoring point. If the deviation exceeds 15%, mark it as abnormal. Combine this with displacement data for verification to ensure that the pressure change matches the displacement increase.

[0132] If the outlier during adjustment is due to incorrect parameter input, the standardized parameters are re-entered and calculated. If it is due to changes in working conditions, it is corrected by combining the latest groundwater depth and support constraint data. If it is due to logical deviation, the weight coefficients of the constitutive model are finely adjusted. After adjustment, a second verification is performed, and the final output is a non-ultimate earth pressure value that conforms to the specifications and fits the actual measurement.

[0133] S5. Preset displacement change rate threshold and parameter calibration rules, verify and calibrate the non-limit state earth pressure based on the displacement change rate threshold and parameter calibration rules, and update the non-limit state earth pressure according to the verification and calibration results.

[0134] As a preferred embodiment, the preset displacement change rate threshold and parameter calibration rules, based on which the non-limit state earth pressure is verified and calibrated, and the non-limit state earth pressure is updated according to the verification and calibration results, include the following steps:

[0135] S51. Based on the physical and mechanical parameters of the soil, the data from the soil pressure calculation equipment, and the engineering boundary conditions, preset the displacement change rate threshold and parameter calibration rules.

[0136] Specifically, the foundation threshold is first determined based on soil cohesion and internal friction angle. For cohesive soils with high deformation ductility, the threshold is set at 0.1-0.3 mm / d. For sandy soils with strong deformation abruptness, the threshold is narrowed to 0.05-0.1 mm / d. For soft soils with low compression modulus, the threshold is further relaxed by 10%-20%. The accuracy of the threshold is corrected based on the accuracy of the earth pressure calculation equipment (e.g., ±0.01 mm). For every 5 m increase in calculation depth at the engineering boundary, the threshold is lowered by 10%. In areas with strong support constraints, the threshold can be increased by 20%. The parameter calibration rules are based on the equipment monitoring data: when the real-time displacement change rate exceeds the threshold, soil parameters are calibrated first (e.g., using direct shear tests to verify cohesion). If there is a conflict with the engineering boundary (e.g., a sudden drop in groundwater), the soil and water separation parameters in the earth pressure calculation are adjusted simultaneously to ensure that the threshold matches the working conditions and can be dynamically corrected.

[0137] S52. The effective displacement monitoring data is divided into time-series segments. The real-time displacement change rate is calculated for the effective displacement monitoring data after time-series segmentation. The real-time displacement change rate is compared with the displacement change rate threshold. The rationality of the pressure of the non-limit state earth pressure is judged based on the comparison results.

[0138] As a preferred embodiment, the step of segmenting the effective displacement monitoring data into time series, calculating the real-time displacement change rate of the segmented effective displacement monitoring data, comparing the real-time displacement change rate with a displacement change rate threshold, and determining the rationality of the non-limit state earth pressure based on the comparison results includes the following steps:

[0139] S521. Based on the time interval of the effective displacement monitoring data collection and the engineering construction stage, set the time sequence segmentation rules, and divide the effective displacement monitoring data into segments according to the time sequence segmentation rules.

[0140] Specifically, based on the collection time interval of effective displacement monitoring data, the segment duration is set to 1-2 hours for the critical construction period of high-frequency collection (10-50Hz), and the segment duration is extended to 12-24 hours for the stable period of low-frequency collection (1-6 hours / time). Then, the construction stages are matched, with the foundation pit excavation, support construction, and main structure construction as nodes. The time interval is superimposed with the construction nodes to clarify the core rule of "segmenting the excavation period by hour and segmenting the support period by day after completion". The construction procedures corresponding to each segment are marked simultaneously. When segmenting, the effective displacement monitoring data is first sorted in ascending order of collection time. Then, according to the time sequence segmentation rules, the data is split with the construction nodes as the boundary to ensure that each segment contains a complete time sequence, monitoring point number and displacement value. Finally, the continuity of the segments is checked, and segments with overlapping or missing time are eliminated to ensure that the segmentation logic is consistent with the construction process and data collection rules.

[0141] S522. For the effective displacement monitoring data in each segment, group them according to the monitoring point number, and calculate the real-time displacement change rate set by dividing the displacement difference between adjacent time periods by the time interval.

[0142] Specifically, first identify the core related fields of the effective displacement monitoring data within each segment, and use the monitoring point number as the grouping basis. Then, use the "grouping and aggregation" function of the data processing tool to group the displacement data with the same number into independent data groups. Within each group, sort the data in ascending order by the acquisition time to ensure the continuity of the time sequence.

[0143] Subsequently, for each data set, the displacement values ​​and corresponding acquisition times of two adjacent acquisition periods are extracted: let the displacement of the previous period be S1 and the time be T1, and the displacement of the next period be S2 and the time be T2. The change rate of a single monitoring point in a single time period is calculated using the formula "real-time displacement change rate = (S2-S1) / (T2-T1)". All adjacent data pairs within each group are iterated sequentially to generate structured data containing "monitoring point number, time period, and displacement change rate". Finally, the calculation results of all monitoring points are integrated to form the real-time displacement change rate set corresponding to each segment. During this process, the consistency of time intervals needs to be verified, and data pairs with abnormal intervals are removed to ensure accuracy.

[0144] S523. Compare the real-time displacement change rate in the real-time displacement change rate set with the displacement change rate threshold one by one, and determine the rationality of the pressure of the non-limit state earth pressure based on the comparison results.

[0145] Specifically, a correlation mapping is first established between "monitoring point number - real-time displacement change rate - displacement change rate threshold - non-ultimate earth pressure" to ensure accurate matching of data from the same monitoring point. Then, each monitoring point is compared individually by its number: if the real-time displacement change rate is less than or equal to the threshold, the soil deformation is stable, and the calculated non-ultimate earth pressure conforms to the "deformation and pressure matching" rule, thus deemed reasonable. If the change rate exceeds the threshold, analysis is needed in conjunction with soil parameters and constraints. If a short-term surge is caused by construction disturbance, and the earth pressure does not exceed the specified range, it is temporarily classified as "to be observed," and the subsequent change rate is continuously tracked. If the change rate consistently exceeds the threshold and the earth pressure approaches the limit value, the pressure may be dangerous, thus deemed unreasonable. If the change rate approaches the threshold (reaching 80%-100% of the threshold), the earth pressure calculation logic needs to be reviewed, parameters fine-tuned based on displacement data, and then a final judgment made to ensure that the reasonable conclusion aligns with the actual stress state of the soil.

[0146] S53. Based on the rationality of pressure and parameter calibration rules, verify the key pressure parameters of the calibrated displacement earth pressure constitutive model and update the non-limit state earth pressure.

[0147] Specifically, the pressure rationality judgment result is first bound to the parameter calibration rules, and different judgment scenarios are classified and processed: for monitoring points judged to be reasonable, the corresponding key pressure parameters are directly retained and verified; for those "to be observed," the disturbance factors need to be reviewed in conjunction with the construction log, and the displacement correlation parameters (such as the peak displacement correction coefficient) are fine-tuned according to the calibration rules; for those judged to be unreasonable, the mechanical parameters are calibrated first according to the rules using the latest soil test data (re-measured cohesion, internal friction angle), and the correlation weights of pressure and displacement in the constitutive model are adjusted simultaneously. After calibration, the new parameters are substituted into the model for recalculation. If the real-time displacement change rate returns to within the threshold and the pressure meets the specifications, the parameter verification is passed; if it is still abnormal, the calibration is repeated. Finally, the model is updated with the verified parameters, and the corrected non-limit state earth pressure is output, forming a closed loop of "judgment-calibration-verification-update".

[0148] S6. Perform condition adaptation matching between the updated non-limit state earth pressure and the engineering boundary conditions, and generate a non-limit state earth pressure calculation report.

[0149] Specifically, the core parameters such as calculation depth, groundwater depth, and support constraint strength in the engineering boundary conditions are first extracted. A "boundary parameter-earth pressure value" compatibility matching matrix is ​​established. The updated non-limit state earth pressure is associated with the corresponding boundary parameters according to the monitoring point number. During matching, the following are key verifications: whether the earth pressure corresponding to the calculation depth conforms to the vertical increasing law, whether the earth pressure within the groundwater depth range is compatible with the requirements of separate or combined calculation of water and soil, and whether the earth pressure attenuation in areas with strong support constraints is reasonable, ensuring no logical conflicts. After the compatibility meets the standards, a calculation report is generated. The report should include the project overview, data sources (soil parameters, displacement monitoring data), calculation logic (constitutive model, association rules), matching results and verification conclusions, and a table of correspondence between monitoring point numbers and earth pressure values ​​to intuitively present the pressure distribution at each location.

[0150] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating non-limit state earth pressure based on displacement monitoring, characterized in that, Includes the following steps: S1. Obtain soil physical and mechanical parameters, earth pressure calculation equipment data and engineering boundary conditions, and preset the calculation standards for static earth pressure coefficient and ultimate earth pressure coefficient; S2. Set up the displacement monitoring point layout rules according to the static earth pressure coefficient and the ultimate earth pressure coefficient. Based on the displacement monitoring point layout rules and the earth pressure calculation equipment data, arrange displacement sensors. Collect the horizontal displacement data and vertical displacement data of the structure in real time through the displacement sensors, and combine them to obtain effective displacement monitoring data. S3. Based on the theory of elastic plastic deformation of soil, a non-limit state earth pressure coefficient expression is preset, and a displacement earth pressure constitutive model is established by combining soil physical and mechanical parameters and effective displacement monitoring data. S4. Set up the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model according to the engineering boundary conditions, and substitute the effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure. S5. Preset displacement change rate threshold and parameter calibration rules, verify and calibrate the non-limit state earth pressure based on the displacement change rate threshold and parameter calibration rules, and update the non-limit state earth pressure according to the verification and calibration results. S6. Perform condition adaptation matching between the updated non-limit state earth pressure and the engineering boundary conditions, and generate a non-limit state earth pressure calculation report. The preset displacement change rate threshold and parameter calibration rules, based on which the non-limit state earth pressure is verified and calibrated, and the non-limit state earth pressure is updated according to the verification and calibration results, include the following steps: S51. Based on the physical and mechanical parameters of the soil, the data from the soil pressure calculation equipment, and the engineering boundary conditions, preset the displacement change rate threshold and parameter calibration rules. S52. The effective displacement monitoring data is divided into time-series segments. The real-time displacement change rate is calculated for the effective displacement monitoring data after time-series segmentation. The real-time displacement change rate is compared with the displacement change rate threshold. The rationality of the pressure of the non-limit state earth pressure is judged based on the comparison results. S53. Based on the rationality of pressure and parameter calibration rules, verify the key pressure parameters of the calibrated displacement earth pressure constitutive model and update the non-limit state earth pressure. The process of segmenting effective displacement monitoring data over time, calculating the real-time displacement change rate of the segmented effective displacement monitoring data, comparing the real-time displacement change rate with a displacement change rate threshold, and determining the rationality of the non-limit state earth pressure based on the comparison results includes the following steps: S521. Based on the time interval of the effective displacement monitoring data collection and the engineering construction stage, set the time sequence segmentation rules, and divide the effective displacement monitoring data into segments according to the time sequence segmentation rules. S522. For the effective displacement monitoring data in each segment, group them according to the monitoring point number, and calculate the real-time displacement change rate set by dividing the displacement difference between adjacent time periods by the time interval. S523. Compare the real-time displacement change rate in the real-time displacement change rate set with the displacement change rate threshold one by one, and determine the rationality of the earth pressure in the non-limit state based on the comparison results.

2. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 1, characterized in that, The process of setting up displacement monitoring point layout rules based on the static earth pressure coefficient and the ultimate earth pressure coefficient, arranging displacement sensors based on the displacement monitoring point layout rules and earth pressure calculation equipment data, and collecting real-time horizontal and vertical displacement data of the structure through the displacement sensors and combining them to obtain effective displacement monitoring data includes the following steps: S21. Combine the static earth pressure coefficient and the ultimate earth pressure coefficient with the data from the earth pressure calculation equipment to determine the key sections, layout density, and vertical spacing of the monitoring points, and form a rule for the layout of displacement monitoring points. S22. Based on the displacement monitoring point layout rules and earth pressure calculation equipment data, select the appropriate displacement sensor type and install and fix the displacement sensor according to the displacement monitoring point layout rules. S23. Start the installed and fixed displacement sensor to collect the original data of the horizontal displacement and vertical displacement of the structure in real time, and record the collection time and monitoring point number simultaneously. S24. Preprocess the original data of the horizontal displacement and vertical displacement of the structure, and combine the preprocessed original data of the horizontal displacement and vertical displacement of the structure according to the acquisition time and monitoring point number to generate effective displacement monitoring data.

3. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 1, characterized in that, The establishment of a displacement-earth pressure constitutive model based on the theory of elastic-plastic deformation of soil, pre-setting an expression for the non-limit state earth pressure coefficient, and combining soil physical and mechanical parameters with effective displacement monitoring data includes the following steps: S31. Based on the theory of elastic and plastic deformation of soil, it is clarified that the coefficient range of the non-limit state earth pressure coefficient is between the static earth pressure coefficient and the ultimate earth pressure coefficient. S32. Based on the range of coefficient values, a non-limit state earth pressure coefficient expression is preset. The non-limit state earth pressure coefficient expression is based on displacement monitoring data as the core variable, and is associated with the static earth pressure coefficient, the ultimate earth pressure coefficient, and the non-limit state earth pressure coefficient. S33. Combining soil physical and mechanical parameters with effective displacement monitoring data, clarify the key pressure parameters in the expression of the earth pressure coefficient in the non-limit state, and integrate the expression of the earth pressure coefficient in the non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement earth pressure constitutive model.

4. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 1, characterized in that, The process of setting up the non-limit earth pressure calculation logic of the displacement earth pressure constitutive model based on engineering boundary conditions, and substituting effective displacement monitoring data into the displacement earth pressure constitutive model to calculate the non-limit state earth pressure includes the following steps: S41. Extract the calculation engineering depth, groundwater depth and support structure constraint parameters from the engineering boundary conditions, and clarify the boundary constraint conditions for earth pressure calculation. S42. Combine the boundary constraints with the displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transmission calculation logic of the non-ultimate earth pressure, and integrate them to obtain the non-ultimate earth pressure calculation logic. S43. Extract the monitoring point number and calculation depth from the effective displacement monitoring data, and substitute the monitoring point number and calculation depth into the displacement earth pressure constitutive model according to the non-ultimate earth pressure calculation logic to calculate the non-ultimate earth pressure value. S44. Perform compliance verification on the non-limit earth pressure values, and adjust the output of the non-limit earth pressure values ​​according to the compliance verification results.

5. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 2, characterized in that, The process of determining the key sections, layout density, and vertical spacing of monitoring points by combining the static earth pressure coefficient and the ultimate earth pressure coefficient with data from earth pressure calculation equipment, and forming a displacement monitoring point layout rule, includes the following steps: S211. Calculate the pressure coefficient difference between the static earth pressure coefficient and the ultimate earth pressure coefficient, and set the earth pressure change gradient based on the pressure coefficient difference to locate the potential critical zone of earth pressure. S212. Extract the bending resistance data and shear weak section data of the support structure from the data of the earth pressure calculation equipment, and superimpose the potential critical area of ​​earth pressure to lock the key section of the monitoring point; S213. Set the equipment layout density at the key section of the monitoring point according to the earth pressure change gradient to obtain the vertical spacing parameters; S214. Integrate the key cross-sections of monitoring points, equipment layout density, and vertical spacing parameters to form a rule for the layout of displacement monitoring points.

6. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 3, characterized in that, The process of combining soil physical and mechanical parameters with effective displacement monitoring data to clarify the key pressure parameters in the expression of the earth pressure coefficient under non-limit state, and then integrating the expression of the earth pressure coefficient under non-limit state with the soil physical and mechanical parameters and effective displacement monitoring data to establish a displacement earth pressure constitutive model includes the following steps: S331. Extract the cohesion, internal friction angle and compression modulus from the physical and mechanical parameters of the soil as core index parameters, and simultaneously extract the peak displacement value and stable displacement characteristic value from the effective displacement monitoring data. S332. Using the core index parameters, peak displacement value and stable displacement characteristic value as the pressure key parameters, and substituting the pressure key parameters into the expression of the earth pressure coefficient in the non-limit state, the initial pressure values ​​of the pressure key parameters are determined. S333. Compare the initial pressure value with the range of coefficient values, and correct the initial pressure value based on the comparison results to obtain the key pressure parameters. S334. Substitute the key pressure parameters into the expression for the earth pressure coefficient in the non-limit state, and establish a correlation mapping with the soil physical and mechanical parameters and effective displacement monitoring data to form a displacement earth pressure constitutive model.

7. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 4, characterized in that, The process of combining boundary constraints with a displacement earth pressure constitutive model to establish the vertical distribution logic and horizontal transfer calculation logic of non-ultimate earth pressure, and then integrating them to obtain the non-ultimate earth pressure calculation logic, includes the following steps: S421. Analyze the influence weights of earth pressure on the engineering depth, groundwater depth and support structure constraint parameters in the boundary constraint conditions, and clarify the earth pressure correlation between the engineering depth, groundwater depth and support structure constraint parameters. S422. Combine the influence weight of earth pressure and the correlation of earth pressure with the displacement earth pressure constitutive model, and establish the vertical distribution logic of non-ultimate earth pressure by associating the physical and mechanical parameters of the soil with the calculation engineering depth as the vertical reference. S423. Based on the constraint parameters of the support structure, establish the horizontal transmission calculation logic of non-ultimate earth pressure, and clarify the transmission correlation rules between transmission efficiency and constraint strength. S424. Verify the coupling compatibility between the vertical distribution logic and the horizontal transmission logic according to the transmission association rules, eliminate logical conflict points, and integrate them to form the non-limit earth pressure calculation logic.

8. The method for calculating non-limit state earth pressure based on displacement monitoring according to claim 6, characterized in that, The process of determining the initial pressure values ​​of key pressure parameters by substituting core index parameters, peak displacement values, and stable displacement characteristic values ​​into the expression for the earth pressure coefficient under non-limit state includes the following steps: S3321. Unit unification processing is performed on the core index parameters, peak displacement values, and stable displacement characteristic values ​​to obtain a standardized parameter set. The correspondence between each variable in the expression of the earth pressure coefficient in the non-limit state and the standardized parameter set is clarified, and a parameter variable mapping table is established. S3322. According to the parameter variable mapping table, substitute each parameter in the standardized parameter set into the expression of the earth pressure coefficient in the non-limit state to obtain the preliminary values ​​of each pressure key parameter, and classify and organize the preliminary values ​​of each pressure key parameter to form a set of initial pressure values.

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