Method, device and equipment for testing soil dynamic side resistance intensity of steel sheet pile vibration pile sinking and storage medium

Abstract

The application provides a kind of steel sheet pile vibration pile soil dynamic side resistance intensity test method, device, equipment and storage medium, it is related to civil engineering construction technical field, the application is by obtaining the embedding depth and shear wave velocity of target soil layer;Based on embedding depth and shear wave velocity, obtain the time domain signal when three measurement sections of steel sheet pile all enter target soil layer;Based on time domain signal, obtain the fundamental component signal;The envelope amplitude sequence of each measurement section is obtained by polynomial fitting to fundamental component signal;The envelope difference sequence is obtained by difference calculation to the envelope amplitude sequence of adjacent measurement section, and the difference parameter of adjacent measurement section is obtained;The difference parameter is converted into axial force difference based on the cross-sectional area and elastic modulus of steel sheet pile, and the minimum dynamic side resistance intensity is taken as the target dynamic side resistance intensity of target soil layer, the precise quantitative measurement of minimum dynamic side resistance intensity of soil under complex forced vibration condition is realized.

Description

Technical Field

[0001] This application relates to the field of civil engineering construction technology, and in particular to a method, apparatus, equipment and storage medium for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles. Background Technology

[0002] Vibratory pile driving technology has broad application prospects in sheet pile projects such as deep foundation pit support and river management due to its advantages such as high construction efficiency and environmental friendliness. In complex deep foundation construction scenarios, accurately calculating the dynamic lateral resistance strength of the soil under high-frequency forced vibration is crucial for the selection of vibratory hammer equipment, the assessment of pile driving feasibility, and ensuring construction safety in the early stages of the project.

[0003] Existing methods for testing the dynamic side resistance strength of soil in vibratory sheet pile driving typically employ a single, fixed excitation frequency for driving and place strain sensors on the sheet pile body to collect dynamic strain data. In the data processing stage, most existing technologies directly extract a segment of the original strain signal in the time domain, simply calculate the difference between the peaks and troughs or directly obtain the arithmetic mean of the original extreme values, and then substitute this into mechanical formulas to calculate the soil side friction resistance between adjacent sections.

[0004] However, vibratory pile driving is a non-stationary dynamic process accompanied by high-frequency mechanical impact and large soil deformation. The original signal inevitably contains high-frequency noise from the eccentric wheel of the equipment, and as the sheet pile is driven deeper into the soil, the signal experiences severe low-frequency baseline drift. Existing methods directly average the extreme values ​​based on the original coarse signal, failing to effectively isolate environmental noise and baseline drift interference. This results in extracted stress characteristics that do not accurately reflect the pure frictional response between the soil and the pile, leading to significant testing errors under complex geological conditions. Therefore, existing technologies suffer from the technical problem of poor accuracy in soil dynamic lateral resistance strength testing due to the inability to effectively isolate the complex noise and baseline drift during vibratory pile driving. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, equipment, and storage medium for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles, in order to solve the technical problem in the prior art that the complex noise and baseline drift during the vibratory pile driving process cannot be effectively removed, resulting in poor accuracy of the test results of the dynamic lateral resistance strength of soil.

[0006] In a first aspect, this application provides a method for testing the dynamic lateral resistance strength of soil in vibratory driving of sheet piles, comprising: Obtain the embedment depth and shear wave velocity of the target soil layer; The natural frequency is calculated based on the embedment depth and shear wave velocity, and multiple test frequencies are determined by combining multiple preset frequency step sizes. Excitation force is applied to the steel sheet pile according to each test frequency, and the time domain signal is obtained when all three measurement sections of the steel sheet pile enter the target soil layer. The natural frequency is calculated based on the embedment depth and the shear wave velocity, and multiple test frequencies are determined by combining multiple preset frequency step sizes. During the single continuous sinking of the steel sheet pile, multiple test frequencies are switched sequentially to apply excitation force to the steel sheet pile according to each test frequency, and to obtain the time domain signal when all three measurement sections of the steel sheet pile enter the target soil layer. Polynomial fitting is performed on the fundamental component signal to obtain the corrected strain sequence. The envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section. The envelope amplitude sequences of adjacent measurement sections are differentially calculated to obtain the envelope difference sequence. The envelope difference sequence is then integrally integrated to obtain the integration area. The quotient of the integration area and the number of cycles contained in the time window is used as the difference parameter between adjacent measurement sections. The differential parameters are converted into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles. The axial force differences are converted into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections. The minimum dynamic side resistance strength is taken as the target dynamic side resistance strength of the target soil layer.

[0007] Optionally, the method further includes: Using the fundamental component signal of the first measurement section among the three measurement sections as the reference signal, the time delay difference between the fundamental component signals of the second and third measurement sections and the reference signal is calculated respectively. Based on the time delay difference, translation compensation is performed on the fundamental component signals of the second measurement section and the third measurement section to construct the aligned fundamental component signals. The aligned fundamental component signals include the reference signal and the translation-compensated fundamental component signals of the second and third measurement sections. Polynomial fitting is performed on the fundamental component signal to obtain the corrected strain sequence. Envelope extraction is then performed on the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence for each measurement section, including: Polynomial fitting is performed on the aligned fundamental component signal to obtain the corrected strain sequence. The envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section.

[0008] Optionally, polynomial fitting is performed on the aligned fundamental component signal to obtain a corrected strain sequence. Envelope extraction is then performed on the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence for each measurement section, including: Based on the time-series data points of the aligned fundamental component signal, a quadratic or cubic polynomial function is constructed. Each discrete sampling point of the aligned fundamental component signal is substituted into the polynomial function for calculation to obtain the offset trend sequence. The polynomial function includes a constant term, a first-order term, a quadratic term, or a cubic term. The first-order term is formed by multiplying the first-order fitting coefficient with the sampling time as the independent variable, the quadratic term is formed by multiplying the second-order fitting coefficient with the square of the sampling time, and the cubic term is formed by multiplying the third-order fitting coefficient with the cube of the sampling time. The aligned fundamental component signal is converted into a digital sampling sequence, and a corrected strain sequence is constructed based on the difference between the corresponding data points in the digital sampling sequence and the offset trend sequence. Multiple local maxima in the correction strain sequence are identified within a preset time window. Spline interpolation is then performed on these local maxima to obtain the envelope amplitude sequence for each measurement section.

[0009] Optionally, the natural frequency is calculated based on the embedment depth and shear wave velocity, and multiple test frequencies are determined by combining multiple preset frequency step sizes. During a single continuous sinking of the sheet pile, multiple test frequencies are switched sequentially to apply excitation force to the sheet pile according to each test frequency, and the time-domain signal when all three measurement sections of the sheet pile enter the target soil layer is obtained, including: The natural frequency is calculated based on the burial depth and shear wave velocity, and multiple test frequencies are determined based on the natural frequency and multiple preset frequency steps. The depth of soil penetration at the first, second, and third measurement sections is detected by a depth sensor. The upper and lower boundary depths of the target soil layer are respectively taken as the first depth and the second depth, where the first depth is the burial depth. When the depth of the third measuring section at the top is greater than the first depth and the depth of the first measuring section at the bottom is less than the second depth, the effective depth range in which all measuring sections simultaneously sink into the target soil layer is determined. During the process of the sheet pile continuously sinking into the effective depth range, the vibration equipment is controlled to switch multiple test frequencies in sequence to apply excitation force to the sheet pile, continuously record the strain data of the first measurement section, the second measurement section and the third measurement section, and segment the strain data based on the timestamp of the switch test frequency to obtain the time domain signal corresponding to each test frequency.

[0010] Optionally, each measuring section of the steel sheet pile is symmetrically equipped with a first strain gauge and a second strain gauge, and the time domain signal of each measuring section includes the first strain value collected by the first strain gauge and the second strain value collected by the second strain gauge. Based on the time-domain signal, the axial strain sequence of each measurement section is calculated. Empirical mode decomposition is used to separate the modes of the axial strain sequence, obtaining multiple target intrinsic mode sequences. Based on the reference period corresponding to each test frequency, the fundamental component signal is determined, including: Calculate the average of the first and second strain values ​​to obtain the axial strain sequence for each measurement section; Based on the maximum and minimum points in the axial strain sequence, spline interpolation is performed on the maximum and minimum points respectively to obtain the upper envelope sequence and the lower envelope sequence. Then, a mean sequence is constructed based on the mean of the corresponding data points in the upper and lower envelope sequences. The difference between the corresponding data points in the axial strain sequence and the mean sequence is used as the candidate mode sequence. The candidate mode sequence is used as the intermediate axial strain sequence. The difference between the corresponding data points in the intermediate axial strain sequence and the mean sequence is used as the candidate mode sequence again until the candidate mode sequence meets the preset convergence condition, thus obtaining the intrinsic mode sequence. The difference between the corresponding data points in the axial strain sequence and the intrinsic mode sequence is used as the residual sequence, and the residual sequence is used as the target axial strain sequence. Based on the maximum and minimum points in the target axial strain sequence, spline interpolation is performed on the maximum and minimum points respectively to obtain multiple target intrinsic mode sequences. The fundamental frequency eigenmode sequence is determined from the target eigenmode sequence based on the reference period corresponding to each test frequency, in order to construct the fundamental component signal.

[0011] Optionally, an envelope difference sequence is obtained by differential calculation of the envelope amplitude sequences of adjacent measurement sections, and a rectangular integral is performed on the envelope difference sequence to obtain the integration area. The quotient of the integration area and the number of periods contained within the time window is used as the difference parameter between adjacent measurement sections, including: The two envelope amplitude sequences of adjacent measurement sections are respectively denoted as the first amplitude sequence and the second amplitude sequence, and the difference between the data points in the first amplitude sequence and the corresponding data points in the second amplitude sequence is taken as the envelope difference sequence; The product of the sum of multiple data points in the envelope difference sequence within the time window and the preset sampling time interval is used as the integration area; The number of cycles within the time window is counted, and the quotient of the integral area and the number of cycles is used as the difference parameter between adjacent measurement sections.

[0012] Optionally, the differential parameters are converted into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles, and the axial force differences are converted into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections, including: The product of the differential parameter corresponding to each test frequency, the cross-sectional area of ​​the sheet pile, and the elastic modulus of the sheet pile is used as the axial force difference value corresponding to each test frequency. The ratio of the axial force difference corresponding to each test frequency to the outer surface area of ​​the sheet pile between adjacent measurement sections is taken as the local dynamic side resistance strength of adjacent measurement sections at each test frequency, and the average value of the local dynamic side resistance strength corresponding to each test frequency is taken as the dynamic side resistance strength at each test frequency.

[0013] Secondly, this application provides a testing device for the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles, comprising: The acquisition module is used to obtain the embedment depth and shear wave velocity of the target soil layer; The determination module is used to calculate the natural frequency based on the embedment depth and shear wave velocity, and determine multiple test frequencies in combination with multiple preset frequency step sizes. During the single continuous sinking of the steel sheet pile, multiple test frequencies are switched sequentially to apply excitation force to the steel sheet pile according to each test frequency, and to obtain the time domain signal when all three measurement sections of the steel sheet pile enter the target soil layer. The calculation module is used to calculate the axial strain sequence of each measurement section based on the time-domain signal, perform mode separation on the axial strain sequence using empirical mode decomposition to obtain multiple target intrinsic mode sequences, and determine the fundamental component signal based on the reference period corresponding to each test frequency. The fitting module is used to perform polynomial fitting on the fundamental component signal to obtain the corrected strain sequence. Within a preset time window, the envelope of the corrected strain sequence is extracted to obtain the envelope amplitude sequence of each measurement section. The calculation module is also used to perform differential calculation on the envelope amplitude sequences of adjacent measurement sections to obtain the envelope difference sequence, perform rectangular integration on the envelope difference sequence to obtain the integration area, and use the quotient of the integration area and the number of cycles contained in the time window as the difference parameter of adjacent measurement sections. The conversion module is used to convert differential parameters into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles, convert the axial force differences into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections, and use the minimum dynamic side resistance strength as the target dynamic side resistance strength of the target soil layer.

[0014] Thirdly, this application provides an electronic device, comprising: Memory, used to store computer programs; A processor for executing a computer program to implement the steps of a method for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles as described in the first aspect above.

[0015] Fourthly, this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the steps of the method for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles as described in the first aspect above.

[0016] This application provides a method for testing the dynamic side resistance strength of soil during vibratory sheet pile driving. Through multi-frequency scanning, it comprehensively captures the dynamic response of the soil under different forced vibration states, avoiding the limitations of single-frequency testing and ensuring the validity and consistency of the collected data in the spatial dimension. It eliminates high-frequency mechanical impact noise and clutter interference from the construction environment, extracting extremely pure dynamic strain characteristics directly corresponding to the dominant frequency of the vibratory hammer. It eliminates the low-frequency baseline drift caused by continuous sheet pile driving, significantly improving the stability of subsequent processing. It accurately quantifies the dynamic deformation difference within the specified interval. It determines the ultimate side friction resistance state most favorable for overcoming soil resistance, providing extremely accurate data for the scientific selection of pile drivers on-site.

[0017] Furthermore, in acquiring the time-domain signal, this application symmetrically sets up a first strain gauge and a second strain gauge at each measurement section of the sheet pile to collect two strain values ​​and calculate the mean value to obtain the axial strain sequence. Subsequently, spline interpolation is used to extract the maximum and minimum points to construct the upper and lower envelopes and the mean sequence. By repeatedly subtracting and iteratively replacing the axial strain sequence and the mean sequence, after meeting the convergence condition, the residual sequence and multiple target intrinsic mode sequences are peeled off layer by layer. Finally, based on the reference period corresponding to the test frequency, the dominant frequency intrinsic mode sequence is locked to construct the fundamental component signal. This solves the technical barrier of existing technologies that result in severely distorted test results and cannot adapt to complex working conditions, and greatly improves the test accuracy of dynamic side resistance strength. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart illustrating a method for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles, provided in an embodiment of this application. Figure 2 A schematic flowchart illustrating the method for constructing a fundamental component signal provided in an embodiment of this application; Figure 3 A flowchart illustrating the method for obtaining the envelope amplitude sequence of each measurement section according to an embodiment of this application; Figure 4 A schematic diagram of the structure of a soil dynamic lateral resistance strength testing device for vibratory pile driving of steel sheet piles provided in this application embodiment; Figure 5 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0020] In the case of vibratory pile driving of sheet piles, the nonlinear soil structure evolution caused by high-frequency excitation force, the complex mechanical impact noise caused by the eccentric wheel of the equipment, and the low-frequency baseline drift of the signal caused by the continuous increase of pile driving depth result in huge errors in the calculation of side friction resistance by directly using the coarse original signal in the existing technology, and cannot guide the selection of equipment.

[0021] This application determines the multi-frequency scanning interval to find the resonance state most likely to cause thixotropic weakening of the soil, and collects time-domain signals while ensuring that multiple measurement sections are simultaneously inserted into the soil. Then, abandoning the traditional simple extremum calculation method, it introduces an empirical mode decomposition algorithm to accurately remove high-frequency environmental noise to reconstruct the pure fundamental wave, and combines polynomial fitting and envelope extraction technology to completely eliminate low-frequency drift interference caused by pile insertion into the soil. Finally, by performing difference and integral mean calculation on the envelope sequences of adjacent sections, the non-stationary transient high-frequency fluctuations are transformed into steady-state strain difference parameters, thereby accurately calculating the dynamic side resistance strength at each test frequency and performing optimization comparison, ultimately achieving accurate quantification of the soil mechanical limit response under complex forced vibration conditions.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The core of this application is to provide a method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles, and a flowchart of a specific implementation method is shown below. Figure 1 As shown, the method includes: Step 101: Obtain the burial depth and shear wave velocity of the target soil layer.

[0024] In this step, the target soil layer refers to the specific underground soil layer whose dynamic lateral resistance strength needs to be tested. The embedment depth refers to the vertical depth of the top surface of the target soil layer from the ground surface. The shear wave velocity refers to the propagation speed of shear waves within the target soil layer.

[0025] In this embodiment, the physical parameters of the silty target soil layer beneath the pile-driving area are extracted by reading the geological exploration report of construction site A. Specifically, the shear wave velocity of the target soil layer can be obtained using an on-site wave velocity meter. Simultaneously, the burial depth of the target soil layer was determined through borehole sampling analysis. .

[0026] Step 102: Calculate the natural frequency based on the embedment depth and the shear wave velocity, and determine multiple test frequencies by combining multiple preset frequency step sizes. During the single continuous sinking of the sheet pile, switch multiple test frequencies in sequence to apply excitation force to the sheet pile according to each test frequency, and obtain the time domain signal when all three measurement sections of the sheet pile enter the target soil layer.

[0027] In this step, the test frequency refers to the periodic vibration frequency applied to the sheet pile by the excitation equipment. The time-domain signal refers to the data sequence representing the deformation state of the sheet pile, continuously acquired over time. The measurement section refers to the horizontal cross-section set at a specified height on the sheet pile for mounting strain sensors.

[0028] Step 201: Calculate the natural frequency based on the burial depth and shear wave velocity, and determine multiple test frequencies based on the natural frequency and multiple preset frequency step sizes.

[0029] In this embodiment, the natural frequency of the target soil layer is estimated according to the formula that the natural frequency equals the shear wave velocity divided by four times the burial depth. That is, the natural frequency equals the quotient of the shear wave velocity and four times the burial depth. Its physical meaning is that, assuming the target soil layer is covered by a hard bedrock or hard soil layer, when vibration waves propagate and interfere within the covering soil layer, the fundamental frequency most likely to induce soil resonance is the ratio of the shear wave velocity to four times the soil layer thickness. This formula is widely applicable to single-layer overburden soil conditions such as soft soil, sandy soil, and cohesive soil with relatively uniform geological distribution. Then, multiple preset frequency steps are superimposed around this natural frequency to obtain multiple test frequencies.

[0030] The preset multiple frequency steps refer to a number of frequency offsets relative to the inherent frequency that are fixed absolute values. For example, they can be set to minus 5 Hz, minus 3 Hz, minus 1 Hz, plus 1 Hz, plus 3 Hz, and plus 5 Hz, thus obtaining six test frequencies. The selection principle for this frequency step is: since the frequency conversion adjustment accuracy of conventional construction vibratory hammers is usually between 1 Hz and 2 Hz, the selection... The fixed absolute step size effectively covers the core frequency band near the soil resonance frequency while meeting the actual adjustable accuracy requirements of the mechanical equipment. If geological surveys show a large gradient in soil shear wave velocity or extremely high soil stiffness, the soil resonance peak will tend to be gentle. In this case, the frequency step size can be increased proportionally to ensure that the test frequency can fully capture the minimum point of dynamic side resistance strength reduction. The reasonable coverage of this step size directly determines whether the measured minimum dynamic side resistance strength is the true minimum value, thereby ensuring the safety redundancy of the hammer selection data.

[0031] Step 202: Detect the soil penetration depth of the first measurement section, the second measurement section and the third measurement section using a depth sensor. The upper boundary depth and the lower boundary depth of the target soil layer are respectively taken as the first depth and the second depth, where the first depth is the burial depth.

[0032] The target soil layer has a specific physical thickness in the underground medium. The upper boundary depth is the vertical depth of the top surface of the target soil layer from the ground surface, and the lower boundary depth is the vertical depth of the bottom surface of the target soil layer from the ground surface.

[0033] In this embodiment, the depth sensor employs a wire-type displacement sensor or a laser rangefinder. The sensor's fixed base is mounted on a stationary guide frame or reference beam on the ground surface, and its measuring movable end is rigidly connected to the top of the sheet pile. Since the elevation of each measuring section on the sheet pile is a known fixed value, the penetration depth of each section can be calculated in real time by subtracting the pile top displacement recorded by the depth sensor. Simultaneously, the data acquisition terminal of the depth sensor and the multi-channel data acquisition instrument of the strain gauge use the same system clock for hardware triggering synchronization to ensure strict consistency between the penetration depth judgment and strain signal acquisition in time, and the measurement accuracy can be controlled at the millimeter level.

[0034] In this embodiment, the excitation device is a vibratory hammer installed on top of the sheet pile. It generates periodic excitation force through the periodic rotation of an eccentric wheel. The vibratory hammer is controlled according to the current test frequency to apply excitation force to the sheet pile, causing it to sink. Simultaneously, depth sensors installed on the sheet pile continuously detect the vertical depth of the first, second, and third measurement sections below the ground surface, i.e., the penetration depth of each measurement section. The depth sensors provide real-time feedback on the penetration depth of each measurement section, which is used in step 203 to determine whether all measurement sections have synchronously sunk into the effective depth range.

[0035] Step 203: When the depth of the third measuring section at the top is greater than the first depth and the depth of the first measuring section at the bottom is less than the second depth, determine the effective depth range in which all measuring sections simultaneously sink into the target soil layer.

[0036] The effective depth range refers to the vertical depth range within which the first, second, and third measuring sections are simultaneously completely within the target soil layer during a single continuous sinking of the sheet pile.

[0037] In this embodiment, the control system continuously and dynamically compares the penetration depth of each measurement section, calculated and acquired in real time, with a preset boundary depth. When the data from the depth sensor indicates that the penetration depth of the third measurement section at the uppermost elevation of the sheet pile has exceeded the first depth (the upper boundary), and the penetration depth of the first measurement section at the lowermost elevation is still less than the second depth (the lower boundary), the control system determines that the entire sensing and monitoring section of the sheet pile has synchronously sunk into the target soil layer and entered the effective depth range. This ensures that the pile body area detected by each section is completely in the same single soil layer medium, eliminating interference from multi-soil layer mixing introduced by the sheet pile spanning different strata.

[0038] Step 204: While the sheet pile continues to sink into the effective depth range, control the excitation equipment to sequentially switch multiple test frequencies to apply excitation force to the sheet pile, continuously record the strain data of the first measurement section, the second measurement section and the third measurement section, and segment the strain data based on the timestamp of the switched test frequencies to obtain the time domain signal corresponding to each test frequency.

[0039] Strain data refers to the mechanical deformation characteristic data collected and output by the first and second strain gauges set on each measurement section when the steel sheet pile is deformed by forced vibration of the excitation equipment. It includes the first and second strain values ​​of the first measurement section, the first and second strain values ​​of the second measurement section, and the first and second strain values ​​of the third measurement section. It includes axial deformation characteristics and bending characteristics, and is presented in the form of a digital sampling sequence or alternating data stream that is continuously recorded over time.

[0040] In this embodiment, after the control system determines that all measurement sections have synchronously sunk into the effective depth range, during the dynamic single stroke of the sheet pile continuously sinking downwards, the control system performs uninterrupted multi-frequency continuous scanning and signal segmentation interception actions. Specifically, the control system calls a preset frequency conversion sequence containing multiple different test frequencies, and controls the excitation equipment to first apply a high-frequency alternating excitation force to the sheet pile at the first test frequency in the frequency conversion sequence. While the excitation equipment is vibrating and driving the pile at the first test frequency, the multi-channel data acquisition instrument continuously collects, records, and stores the first and second strain values ​​of the first, second, and third measurement sections in a high-frequency continuous sampling mode.

[0041] In practical implementation, the frequency control systems of the data acquisition terminal and the excitation equipment can be synchronously triggered using a joint hardware clock. Since the total spatial distance between the third and first measurement sections is pre-set to be less than the physical thickness of the target soil layer in the vertical direction, it geometrically limits the longitudinal advance length of the effective depth range. The control system controls the duration of continuous application at the current test frequency based on a preset cycle count value, which corresponds to a physical duration of two to three seconds. When the control system determines that the duration of the current test frequency has reached the cycle count value, it continuously sends a switching control command to the excitation equipment, instantly and uninterruptedly adjusting the equipment to the next test frequency in the frequency conversion sequence to perform the application action. At the moment each switching control command is issued, the control system records the absolute time of the current action and generates a corresponding switching timestamp.

[0042] The process of the multi-channel data acquisition instrument continuously recording the strain data of each section and the control system recording the action time and generating a switching timestamp, which is described above, is continuously and cyclically executed during the sinking process of the steel sheet pile continuously passing through the effective depth range, until all test frequencies included in the frequency conversion sequence are driven in sequence.

[0043] Throughout the entire frequency conversion scanning process, the multi-channel data acquisition instrument continuously retains data, forming a complete strain data stream containing all test frequency characteristics. During discrete data processing, the control system retrieves this complete strain data stream and aligns its time axis with the previously stored switching timestamps. Each switching timestamp serves as a dividing point for horizontal trimming of the data stream, segmenting the entire complete strain data stream and labeling it according to its frequency. This allows for the extraction of segmented time-domain signals corresponding to each test frequency within the single continuous sinking stroke of a single sheet pile.

[0044] In this embodiment, three measurement sections are necessary because underground soil often exhibits local heterogeneity, such as inclusions of gravel or varying soil hardness. Data obtained from only two sections lacks statistical comparison and is prone to distortion due to sudden local geological changes. Using three sections allows for the simultaneous calculation and averaging of the lateral resistance parameters of two local areas, effectively mitigating random errors and ensuring the statistical significance of the results. Furthermore, the spacing between adjacent measurement sections can be preset to 0.25m. This spacing is based on the following: if the spacing is too large, the measurement sections may span different soil layers; if the spacing is too small, the axial strain difference between the two sections will be too small and easily masked by the sensor's background noise. A spacing of 0.25m ensures that all sections are within the same homogeneous target soil layer while generating sufficiently clear and distinguishable strain differential signals.

[0045] Step 103: Based on the time-domain signal, calculate the axial strain sequence of each measurement section, use empirical mode decomposition to perform mode separation on the axial strain sequence to obtain multiple target intrinsic mode sequences, and determine the fundamental component signal based on the reference period corresponding to each test frequency.

[0046] In this step, the axial strain sequence refers to a one-dimensional time data array representing the pure axial deformation of the sheet pile after eliminating bending moment interference. Empirical mode decomposition (EMD) is a data processing algorithm that decomposes a non-stationary signal into multiple eigenmode functions of different frequencies. The fundamental component signal refers to the pure vibration waveform data corresponding to the dominant frequency of the excitation equipment after removing high-frequency environmental noise.

[0047] like Figure 2 As shown, Figure 2 This is a flowchart illustrating the method for constructing a fundamental component signal provided in an embodiment of this application.

[0048] Step 301: Calculate the average of the first strain value and the second strain value to obtain the axial strain sequence of each measurement section.

[0049] In this embodiment, each measurement section of the sheet pile is symmetrically equipped with a first strain gauge and a second strain gauge. The time-domain signal of each measurement section includes the first strain value collected by the first strain gauge and the second strain value collected by the second strain gauge. The average value of the first strain value and the second strain value on the same measurement section is calculated to obtain the axial strain sequence of that measurement section. Since the sheet pile may experience eccentric bending during pile driving, the data from the single-sided strain gauge contains bending strain components. By averaging the values ​​of the two strain gauges symmetrically arranged about the cross-section, the equal and opposite bending strains cancel each other out, leaving only the axial strain reflecting the axial force, thereby eliminating the uneven deformation error caused by eccentric bending.

[0050] Step 302: Based on the maximum and minimum points in the axial strain sequence, perform spline interpolation calculations on the maximum and minimum points respectively to obtain the upper envelope sequence and the lower envelope sequence, and construct the mean sequence based on the mean of the corresponding data points in the upper envelope sequence and the lower envelope sequence.

[0051] In this embodiment, all maxima and minima in the axial strain sequence are identified. Spline interpolation is then performed on the maxima and minima respectively to obtain continuous and smooth upper and lower envelope sequences. The mean of corresponding data points in the upper and lower envelope sequences is then taken to construct a mean sequence. Spline interpolation refers to using a cubic spline function to smoothly fit discrete extreme points, ensuring that adjacent extreme points are smoothly connected by piecewise cubic polynomials, thus obtaining an envelope without severe oscillations. The constructed mean sequence reflects the local average trend of the axial strain sequence and serves as the basis for subsequent screening of intrinsic modes.

[0052] Step 303: Use the difference between the corresponding data points in the axial strain sequence and the mean sequence as the candidate mode sequence, use the candidate mode sequence as the intermediate axial strain sequence, and use the difference between the corresponding data points in the intermediate axial strain sequence and the mean sequence as the candidate mode sequence again, until the candidate mode sequence meets the preset convergence condition, and obtain the intrinsic mode sequence.

[0053] In this embodiment, the difference between corresponding data points in the axial strain sequence and the mean sequence is used as a candidate mode sequence. It is determined whether the candidate mode sequence meets a preset convergence condition. If not, the candidate mode sequence is used as an intermediate axial strain sequence, and the extreme value identification, spline interpolation, and mean calculation process in step 302 are repeated, and the difference is calculated again to obtain a new candidate mode sequence. This process is iterated repeatedly until the candidate mode sequence meets the preset convergence condition, at which point the candidate mode sequence is used as the intrinsic mode sequence. The preset convergence condition refers to the criterion for measuring whether a candidate mode sequence has become an intrinsic mode. This embodiment adopts the Cauchy convergence criterion, which is recognized in empirical mode decomposition, i.e., judging whether the candidate mode sequence has become an intrinsic mode in two adjacent iterations. Next and first The resulting candidate mode sequence and The ratio of standard deviations between The specific formula for calculating the ratio of standard deviations is as follows:

[0054] In the formula, This represents the total number of data points within the time window. When making judgments, the ratio of this standard deviation is required. The threshold value is less than a preset threshold. This preset threshold is strictly selected to be between 0.2 and 0.3; this selection is based on empirical criteria for processing non-stationary mechanical vibration signals: when the threshold is within this range, it ensures that the decomposed intrinsic mode sequence has a pure single-frequency physical meaning, while preventing the algorithm from distorting the fundamental signal and wasting computational resources due to excessive iteration. This threshold range has good universality for various types of forced vibration strain signals of steel sheet piles. Alternatively, it can be set such that the difference between the number of extreme points and the number of zero-crossing points in the sequence does not exceed one.

[0055] Step 304: Take the difference between the corresponding data points in the axial strain sequence and the intrinsic mode sequence as the residual sequence, and take the residual sequence as the target axial strain sequence. Then, based on the maximum and minimum points in the target axial strain sequence, perform spline interpolation calculations on the maximum and minimum points respectively to obtain multiple target intrinsic mode sequences.

[0056] In this embodiment, the difference between the corresponding data points in the axial strain sequence and the intrinsic mode sequence obtained in step 303 is used as the residual sequence, and this residual sequence is used as the target axial strain sequence. Spline interpolation and sieving are then performed again based on the maximum and minimum points in the target axial strain sequence to separate the next intrinsic mode sequence. This process is repeated, and each separated intrinsic mode sequence is subtracted from the current sequence, and the remaining residual sequence is further decomposed to obtain multiple target intrinsic mode sequences arranged from high frequency to low frequency. The reason for layer-by-layer decomposition is that the original axial strain sequence is composed of multiple vibration components of different frequencies. Only by peeling away the layers can the component corresponding to the dominant frequency of the forced vibration be separated individually.

[0057] Step 305: Determine the dominant frequency eigenmode sequence from the target eigenmode sequence based on the reference period corresponding to each test frequency, so as to construct the fundamental component signal.

[0058] In this embodiment, the reference period refers to the vibration period corresponding to the current test frequency, i.e., the reciprocal of the test frequency. The average period of each target intrinsic mode sequence is calculated, and the target intrinsic mode sequence with the average period closest to the reference period is selected as the dominant frequency intrinsic mode sequence. The fundamental wave component signal of the measurement section at the test frequency is constructed using this dominant frequency intrinsic mode sequence. Since the dominant frequency of the forced vibration is consistent with the excitation frequency of the vibratory hammer, i.e., the test frequency, the intrinsic mode sequence closest to the reference period is the dominant frequency component reflecting the pure frictional response between the soil and the pile. The fundamental wave component signal reconstructed in this way has eliminated high-frequency environmental noise and clutter. Steps 301 to 305 above are performed on the axial strain sequences of the three measurement sections at each test frequency to obtain the fundamental wave component signal of each measurement section.

[0059] Step 104: Perform polynomial fitting on the fundamental component signal to obtain the corrected strain sequence. Extract the envelope of the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence of each measurement section.

[0060] In this step, the corrected strain sequence refers to a horizontal alternating data array after removing the effects of low-frequency baseline drift. The time window refers to a specific time segment artificially selected for extracting stable pile characteristics. The envelope amplitude sequence refers to a data sequence representing the overall vibration amplitude profile, composed of signal peaks and extreme points.

[0061] like Figure 3 As shown, Figure 3 This is a flowchart illustrating the method for obtaining the envelope amplitude sequence of each measurement section according to an embodiment of this application.

[0062] Step 401: Using the fundamental component signal of the first measurement section as the reference signal, calculate the time delay difference between the fundamental component signals of the second and third measurement sections and the reference signal.

[0063] In this embodiment, considering the propagation time delay of the excitation force from the pile top to the first, second, and third measurement sections, the fundamental wave component signals of the three sections are misaligned on the time axis. Therefore, the fundamental wave component signal of the first measurement section is used as the reference signal, and the time delay difference between the fundamental wave component signals of the second and third measurement sections and the reference signal is calculated. The time delay difference can be determined by performing a cross-correlation operation on the reference signal and the signal to be aligned; that is, the time shift corresponding to the maximum value of the cross-correlation function is taken as the time delay difference of the corresponding measurement section.

[0064] Step 402: Based on the time delay difference, perform translation compensation on the fundamental component signals of the second measurement section and the third measurement section to construct the aligned fundamental component signals. The aligned fundamental component signals include the reference signal and the translation-compensated fundamental component signals of the second and third measurement sections.

[0065] In this embodiment, based on the time delay difference obtained in step 401, the fundamental wave component signals of the second and third measurement sections are translated and compensated along the time axis to align them with the reference signal in phase, thereby constructing the aligned fundamental wave component signals. The aligned fundamental wave component signals include the fundamental wave component signal of the first measurement section, which serves as the reference signal, as well as the translated and compensated fundamental wave component signals of the second and third measurement sections. After translation compensation, the fundamental wave components of the three sections tend to be consistent in phase, differing only in amplitude. This amplitude difference reflects the axial force attenuation caused by the lateral resistance of the soil between adjacent sections. If no compensation is applied and the difference is directly applied point by point between adjacent sections, significant errors will be introduced due to phase misalignment.

[0066] In this embodiment, the translation compensation for the time delay difference addresses the spatial physical propagation lag caused by the elastic wave velocity of the sheet pile material itself. Specifically, the intrinsic propagation velocity of the stress wave in the pile body is determined in advance based on the material density and elastic modulus of the sheet pile, and the maximum time shift retrieval window for cross-correlation function calculation is set in combination with the known physical distance between adjacent measurement sections.

[0067] After extracting the fundamental wave component signals from each measurement section, the time lag of the second and third measurement sections relative to the first measurement section is obtained by optimizing within the maximum time shift retrieval window using a cross-correlation algorithm. This time lag is then used as the physical propagation delay of the pure elastic wave. During translation compensation, the original sampling amplitude matrix of the fundamental wave component signals of each measurement section remains unchanged. Only the time axis arrays of the time series data points of the second and third measurement sections are uniformly subtracted from their respective physical propagation delays. This aligns the same peak or trough characteristics of the measurement sections at different spatial locations along the stress wave propagation path to the same analysis time starting point.

[0068] After phase alignment, the amplitude difference of signals from adjacent measurement sections at the same time coordinate is taken as the energy attenuation response caused by soil lateral drag damping. Subsequently, a corrected strain sequence is constructed by subtracting the aligned digital sampling sequence from the offset trend sequence. Envelope difference and rectangular integral calculations are then performed within a preset time window to directly extract amplitude attenuation characteristics and calculate axial force difference and dynamic lateral drag strength. Step 403: Polynomial fitting is performed on the fundamental component signal to obtain the corrected strain sequence. Envelope extraction is performed on the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence for each measurement section, including: Polynomial fitting is performed on the aligned fundamental component signal to obtain the corrected strain sequence. The envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section.

[0069] In this embodiment, the process of performing polynomial fitting on the fundamental wave component signal to obtain a corrected strain sequence and extracting the envelope amplitude sequence within a preset time window is specifically performed on the aligned fundamental wave component signal. That is, polynomial fitting is performed on the aligned fundamental wave component signal to obtain a corrected strain sequence, and the envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section. This polynomial fitting and envelope extraction process is specifically implemented through steps 411 to 413.

[0070] Step 411: Based on the time-series data points of the aligned fundamental component signal, construct a quadratic or cubic polynomial function. Substitute each discrete sampling point of the aligned fundamental component signal into the polynomial function for calculation to obtain the offset trend sequence. The polynomial function includes a constant term, a linear term, a quadratic term, or a cubic term. The linear term is formed by multiplying the linear fitting coefficient with the sampling time as the independent variable. The quadratic term is formed by multiplying the quadratic fitting coefficient with the square of the sampling time. The cubic term is formed by multiplying the cubic fitting coefficient with the cube of the sampling time.

[0071] In this embodiment, a polynomial function is constructed based on the time-series data points of the aligned fundamental component signal. Each discrete sampling point of the aligned fundamental component signal is then substituted into this polynomial function for calculation to obtain the offset trend sequence. The polynomial function is used to fit the slowly changing low-frequency baseline drift trend in the fundamental component signal caused by the continuous insertion of sheet piles into the soil. For example, a quadratic or cubic polynomial obtained by least squares fitting can be used, and the order of the polynomial can be set according to the smoothness of the baseline drift. Substituting each sampling time point into this polynomial yields the offset trend sequence reflecting the baseline drift.

[0072] Step 412: Convert the aligned fundamental component signal into a digital sampling sequence, and construct a corrected strain sequence based on the difference between the corresponding data points in the digital sampling sequence and the offset trend sequence.

[0073] In this embodiment, the aligned fundamental component signal is converted into a digital sampling sequence, i.e., a discrete numerical sequence arranged according to sampling time. Then, the digital sampling sequence is subtracted point by point from the corresponding data points in the offset trend sequence to construct a corrected strain sequence. That is, at each sampling point, the value of the fundamental component signal is subtracted from the value of the offset trend sequence to deduct low-frequency baseline drift and correct the signal to near the zero mean. The reason for deducting the offset trend first is that baseline drift will cause the subsequently extracted envelope amplitude to rise or fall overall, thus affecting the accuracy of the envelope difference between adjacent sections. Deducting the offset trend ensures that the envelope amplitude truly reflects the amplitude of the forced vibration.

[0074] Step 413: Identify multiple local maxima in the correction strain sequence within a preset time window, perform spline interpolation calculation on the local maxima to obtain the envelope amplitude sequence of each measurement section.

[0075] In this embodiment, multiple local maxima points in the correction strain sequence are identified within a preset time window; these are the data points where the correction strain sequence reaches its peak value in each vibration cycle. Spline interpolation is then performed on these local maxima points, and the peak values ​​are smoothly connected using a cubic spline function to obtain the envelope amplitude sequence of the measurement section. The resulting envelope amplitude sequence reflects the trend of forced vibration amplitude over time and serves as the basis for subsequent calculations of the differential parameters between adjacent sections.

[0076] Step 105: Perform differential calculation on the envelope amplitude sequences of adjacent measurement sections to obtain the envelope difference sequence, perform rectangular integration on the envelope difference sequence to obtain the integration area, and use the quotient of the integration area and the number of cycles contained in the time window as the difference parameter of adjacent measurement sections.

[0077] In this step, the envelope difference sequence refers to the one-dimensional data difference array obtained by subtracting corresponding points from the envelope amplitude sequences of two adjacent measurement sections. The difference parameter refers to the steady-state numerical characteristic that transforms the dynamic difference sequence into a representation of the average force difference within a time window.

[0078] Step 501: Record the two envelope amplitude sequences of adjacent measurement sections as the first amplitude sequence and the second amplitude sequence, respectively, and take the difference between the data points in the first amplitude sequence and the corresponding data points in the second amplitude sequence as the envelope difference sequence.

[0079] In this embodiment, the two envelope amplitude sequences of adjacent measurement sections are respectively denoted as the first amplitude sequence and the second amplitude sequence, and the difference between the data points in the first amplitude sequence and the corresponding data points in the second amplitude sequence is taken as the envelope difference sequence. For example, for the first measurement section and the second measurement section, their envelope amplitude sequences are respectively taken as the first amplitude sequence and the second amplitude sequence; the same process is applied to the second measurement section and the third measurement section. The envelope difference sequence characterizes the attenuation of the forced vibration amplitude between two adjacent measurement sections.

[0080] Step 502: The product of the sum of multiple data points in the envelope difference sequence within the time window and the preset sampling time interval is used as the integration area.

[0081] In this embodiment, the product of the sum of multiple data points of the envelope difference sequence within a time window and a preset sampling time interval is used as the integration area. The preset sampling time interval is explicitly defined as the fixed physical acquisition interval when the hardware device acquires the original time-domain signal, which is equal to the reciprocal of the original acquisition frequency. Multiplying the sum of each data point of the envelope difference sequence within the time window by the sampling time interval is equivalent to performing numerical integration of the envelope difference sequence within the time window using the rectangular method. More complex numerical integration methods such as the trapezoidal method or Simpson's method are not used here because the data acquisition frequency of this system is much higher than the dominant frequency of the pile driving vibration. When the discrete data is extremely dense, the approximate error of the rectangular method has been reduced to less than 1%. In the real-time monitoring of long-term, continuous forced vibration, the addition, subtraction, and multiplication operations of the rectangular integral can greatly save the computing power of the controller, and significantly improve the timeliness of on-site data processing while ensuring sufficient test accuracy. The obtained integration area reflects the cumulative amount of strain attenuation of adjacent sections within the time window.

[0082] Step 503: Calculate the number of cycles in the time window and use the quotient of the integral area and the number of cycles as the difference parameter between adjacent measurement sections.

[0083] In this embodiment, the number of vibration periods contained in the fundamental component signal within the time window is statistically determined, and the quotient of the integral area obtained in step 502 and the number of periods is used as the difference parameter for adjacent measurement sections. The number of periods can be obtained by dividing the time window length by the reference period. Dividing the integral area by the number of periods is equivalent to calculating the average contribution of the envelope difference within a single vibration period, thereby eliminating the influence of different time window lengths and number of periods on the results and obtaining robust difference parameters. The corresponding difference parameters are calculated in the above manner for each test frequency and each pair of adjacent measurement sections.

[0084] Step 106: Based on the cross-sectional area and elastic modulus of the sheet pile, the differential parameters are converted into axial force difference values. Based on the outer surface area of ​​the sheet piles between adjacent measurement sections, the axial force difference values ​​are converted into dynamic side resistance strength at each test frequency. The minimum dynamic side resistance strength is taken as the target dynamic side resistance strength of the target soil layer.

[0085] In this step, the axial force difference refers to the absolute difference in axial force borne by the sheet piles between two adjacent measurement sections. Dynamic side resistance strength refers to the ultimate frictional resistance per unit area of ​​the target soil layer under a specific frequency of excitation. Target dynamic side resistance strength refers to the minimum frictional resistance value obtained at all scanning frequencies.

[0086] Step 601: The product of the differential parameter, the cross-sectional area of ​​the sheet pile, and the elastic modulus of the sheet pile corresponding to each test frequency is taken as the axial force difference value corresponding to each test frequency.

[0087] In this embodiment, based on the relationship in mechanics of materials that axial force equals the product of elastic modulus, cross-sectional area, and axial strain, the product of the differential parameter corresponding to each test frequency, the cross-sectional area of ​​the sheet pile, and the elastic modulus of the sheet pile is used as the axial force difference value corresponding to that test frequency. The cross-sectional area refers to the cross-sectional area of ​​the sheet pile, and the elastic modulus refers to the elastic modulus of the sheet pile material; both are known quantities. This axial force difference reflects the attenuation of the axial force of the pile between two adjacent measurement sections, and this attenuation is caused by the lateral resistance of the soil between the pile and the section.

[0088] Step 602: The ratio of the axial force difference corresponding to each test frequency to the outer surface area of ​​the sheet pile between adjacent measurement sections is taken as the local dynamic side resistance strength of adjacent measurement sections at each test frequency, and the average value of the local dynamic side resistance strength corresponding to each test frequency is taken as the dynamic side resistance strength at each test frequency.

[0089] In this embodiment, the ratio of the axial force difference corresponding to each test frequency to the outer surface area of ​​the sheet piles between adjacent measurement sections is used as the local dynamic lateral resistance strength of the adjacent measurement sections at that test frequency. Since the three measurement sections divide the soil into two extremely small local measurement intervals—between the first and second measurement sections, and between the second and third measurement sections—the local dynamic lateral resistance strength is an intermediate calculation parameter used to characterize the microscopic frictional force within a specific adjacent section interval. However, in actual engineering, it is necessary to evaluate the overall macroscopic frictional response of the target soil layer at a specific vibration frequency. Therefore, by summing all the local dynamic lateral resistance strengths corresponding to each test frequency and taking the arithmetic mean, the microscopic local force is converted into a macroscopic overall characterization, which is then used as the overall dynamic lateral resistance strength at each test frequency. The outer surface area refers to the lateral surface area of ​​the sheet pile in contact with the soil between two adjacent measurement sections.

[0090] Since this embodiment has three measurement sections, two local dynamic side resistance intensities can be obtained between the first and second measurement sections, and between the second and third measurement sections. The average of these two values ​​is the dynamic side resistance intensity at that test frequency. Furthermore, the minimum value among the dynamic side resistance intensities at each test frequency is taken as the target dynamic side resistance intensity for the target soil layer. This minimum dynamic side resistance intensity corresponds to the most favorable side resistance condition for pile driving, providing the most crucial basis for vibratory hammer selection and pile driving feasibility assessment.

[0091] This application embodiment, through multi-frequency scanning, comprehensively captures the dynamic response of soil under different forced vibration states, avoiding the limitations of single-frequency testing; it ensures the validity and consistency of the collected data in the spatial dimension. It eliminates high-frequency mechanical impact noise and clutter interference from the construction environment, extracting extremely pure dynamic strain characteristics directly corresponding to the vibratory hammer's dominant frequency. It eliminates the low-frequency baseline drift caused by continuous sheet pile driving, significantly improving the stability of subsequent processing. It accurately quantifies the dynamic deformation difference within this interval. It determines the ultimate side friction resistance state most favorable for overcoming soil resistance, providing extremely accurate data for the scientific selection of pile drivers on-site.

[0092] Figure 4 This is a schematic diagram of a specific embodiment of a soil dynamic lateral resistance strength testing device for vibratory pile driving of sheet piles provided in this application. (Refer to...) Figure 4 The system may include: Module 21 is used to acquire the embedment depth and shear wave velocity of the target soil layer; The determination module 22 is used to calculate the natural frequency based on the embedment depth and the shear wave velocity, and determine multiple test frequencies in combination with multiple preset frequency step sizes. During the single continuous sinking of the steel sheet pile, multiple test frequencies are switched sequentially to apply excitation force to the steel sheet pile according to each test frequency, and to obtain the time domain signal when all three measurement sections of the steel sheet pile enter the target soil layer. Calculation module 23 is used to calculate the axial strain sequence of each measurement section based on the time domain signal, perform mode separation on the axial strain sequence using empirical mode decomposition to obtain multiple target intrinsic mode sequences, and determine the fundamental component signal based on the reference period corresponding to each test frequency. The fitting module 24 is used to perform polynomial fitting on the fundamental component signal to obtain the corrected strain sequence, and to extract the envelope of the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence of each measurement section. The calculation module 23 is also used to perform differential calculation on the envelope amplitude sequence of adjacent measurement sections to obtain the envelope difference sequence, perform rectangular integration on the envelope difference sequence to obtain the integration area, and use the quotient of the integration area and the number of cycles contained in the time window as the difference parameter of adjacent measurement sections. The conversion module 25 is used to convert differential parameters into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles, convert the axial force differences into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections, and use the minimum dynamic side resistance strength as the target dynamic side resistance strength of the target soil layer.

[0093] The soil dynamic lateral resistance strength testing device for vibratory driving of sheet piles in this application embodiment is used to implement the aforementioned method for testing the soil dynamic lateral resistance strength of vibratory driving of sheet piles. Therefore, the specific implementation of the soil dynamic lateral resistance strength testing device for vibratory driving of sheet piles can be found in the embodiment section of the method for testing the soil dynamic lateral resistance strength of vibratory driving of sheet piles mentioned above. The specific implementation can be referred to the description of the corresponding embodiments, and will not be repeated here.

[0094] Figure 5 A schematic diagram of the hardware structure of the electronic device provided in an embodiment of this application is shown.

[0095] This application also provides an electronic device, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the method for testing the dynamic lateral resistance strength of soil in vibratory driving of sheet piles as described above.

[0096] The electronic device may include a processor 510 and a memory 520 storing computer program instructions.

[0097] Specifically, the processor 510 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0098] Memory 520 may include mass storage for data or instructions. For example, and not limitingly, memory 520 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 520 may include removable or non-removable (or fixed) media. Where appropriate, memory 520 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 520 is non-volatile solid-state memory.

[0099] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to the first aspect of this disclosure.

[0100] The processor 510 reads and executes computer program instructions stored in the memory 520 to implement any of the methods for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles in the above embodiments.

[0101] In one example, the electronic device may also include a communication interface 530 and a bus 540. Wherein, such as Figure 5 As shown, the processor 510, memory 520, and communication interface 530 are connected through bus 540 and complete communication with each other.

[0102] The communication interface 530 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0103] Bus 540 includes hardware, software, or both, that couples components of an online data traffic metering device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 540 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0104] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described methods for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles.

[0105] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory, random access memory, portable hard drives, magnetic disks, or optical disks.

[0106] The embodiments of the present invention also provide a computer program product, which includes a computer program that, when executed by a processor, implements the steps in the embodiments of the test method for the dynamic lateral resistance strength of soil in any of the above-described steel sheet pile vibratory pile driving methods.

[0107] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0108] The present application provides a detailed description of a method and system for testing the dynamic lateral resistance strength of soil in vibratory sheet pile driving. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of these embodiments are merely for the purpose of helping to understand the method and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A method for testing the dynamic lateral resistance strength of soil in vibratory driven steel sheet piles, characterized in that, include: Obtain the embedment depth and shear wave velocity of the target soil layer; The natural frequency is calculated based on the embedment depth and the shear wave velocity, and multiple test frequencies are determined in combination with multiple preset frequency step sizes. During the single continuous sinking of the sheet pile, multiple test frequencies are switched sequentially to apply excitation force to the sheet pile according to each test frequency, and to obtain the time domain signal when all three measurement sections of the sheet pile enter the target soil layer. Based on the time-domain signal, the axial strain sequence of each measurement section is calculated, and the axial strain sequence is modally separated using empirical mode decomposition to obtain multiple target intrinsic mode sequences. Based on the reference period corresponding to each test frequency, the fundamental component signal is determined. The fundamental component signal is fitted with a polynomial to obtain a corrected strain sequence. The envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section. The envelope amplitude sequence of adjacent measurement sections is differentially calculated to obtain an envelope difference sequence. The envelope difference sequence is then integrally integrated to obtain the integration area. The quotient of the integration area and the number of periods contained in the time window is used as the difference parameter of the adjacent measurement sections. The differential parameters are converted into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles. The axial force differences are then converted into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections. The minimum dynamic side resistance strength is then used as the target dynamic side resistance strength of the target soil layer.

2. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 1, characterized in that, The method further includes: Using the fundamental component signal of the first measurement section among the three measurement sections as the reference signal, the time delay difference between the fundamental component signals of the second and third measurement sections and the reference signal is calculated respectively. Based on the time delay difference, the fundamental component signals of the second measurement section and the third measurement section are shifted and compensated to construct an aligned fundamental component signal. The aligned fundamental component signal includes the reference signal and the shifted and compensated fundamental component signals of the second and third measurement sections. The process involves performing polynomial fitting on the fundamental component signal to obtain a corrected strain sequence, and then extracting the envelope of the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence for each measurement section, including: Polynomial fitting is performed on the aligned fundamental component signal to obtain the corrected strain sequence. The envelope of the corrected strain sequence is extracted within a preset time window to obtain the envelope amplitude sequence of each measurement section.

3. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 2, characterized in that, Polynomial fitting is performed on the aligned fundamental component signal to obtain a corrected strain sequence. Envelope extraction is then performed on the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence for each measurement section, including: Based on the time-series data points of the aligned fundamental component signal, a quadratic or cubic polynomial function is constructed. Each discrete sampling point of the aligned fundamental component signal is substituted into the polynomial function for calculation to obtain the offset trend sequence. The polynomial function includes a constant term, a linear term, a quadratic term, or a cubic term. The linear term is formed by multiplying the linear fitting coefficient by the sampling time as the independent variable. The quadratic term is formed by multiplying the quadratic fitting coefficient by the square of the sampling time. The cubic term is formed by multiplying the cubic fitting coefficient by the cube of the sampling time. The aligned fundamental component signal is converted into a digital sampling sequence, and a correction strain sequence is constructed based on the difference between the corresponding data points in the digital sampling sequence and the offset trend sequence. Multiple local maxima in the corrected strain sequence are identified within a preset time window. Spline interpolation is then performed on these local maxima to obtain the envelope amplitude sequence for each measurement section.

4. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 1, characterized in that, The natural frequency is calculated based on the embedment depth and the shear wave velocity, and multiple test frequencies are determined by combining multiple preset frequency step sizes. During a single continuous sinking of the sheet pile, the multiple test frequencies are switched sequentially to apply excitation force to the sheet pile according to each test frequency, and the time-domain signal when all three measurement sections of the sheet pile enter the target soil layer is obtained, including: The natural frequency is calculated based on the burial depth and the shear wave velocity, and multiple test frequencies are determined based on the natural frequency and multiple preset frequency step sizes. The depth of soil penetration at the first, second, and third measurement sections is detected by a depth sensor. The upper and lower boundary depths of the target soil layer are respectively taken as the first depth and the second depth, wherein the first depth is the burial depth. When the depth of penetration of the third measuring section at the uppermost end is greater than the first depth and the depth of penetration of the first measuring section at the lowermost end is less than the second depth, the effective depth range in which all measuring sections simultaneously sink into the target soil layer is determined. During the process of the sheet pile continuously sinking into the effective depth range, the vibration device is controlled to sequentially switch multiple test frequencies to apply vibration force to the sheet pile, continuously record the strain data of the first measurement section, the second measurement section and the third measurement section, and segment the strain data based on the timestamp of the switch test frequencies to obtain the time domain signal corresponding to each test frequency.

5. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 1, characterized in that, Each measuring section of the sheet pile is symmetrically equipped with a first strain gauge and a second strain gauge. The time domain signal of each measuring section includes the first strain value collected by the first strain gauge and the second strain value collected by the second strain gauge. Based on the time-domain signal, the axial strain sequence of each measurement section is calculated. Empirical mode decomposition is used to perform mode separation on the axial strain sequence to obtain multiple target intrinsic mode sequences. Based on the reference period corresponding to each test frequency, the fundamental component signal is determined, including: Calculate the average of the first strain value and the second strain value to obtain the axial strain sequence of each measurement section; Based on the maximum and minimum points in the axial strain sequence, spline interpolation is performed on the maximum and minimum points respectively to obtain the upper envelope sequence and the lower envelope sequence, and a mean sequence is constructed based on the mean of the corresponding data points in the upper envelope sequence and the lower envelope sequence. The difference between the axial strain sequence and the corresponding data point in the mean sequence is used as a candidate mode sequence. The candidate mode sequence is used as an intermediate axial strain sequence. The difference between the intermediate axial strain sequence and the corresponding data point in the mean sequence is used as a candidate mode sequence again until the candidate mode sequence meets the preset convergence condition, thus obtaining the intrinsic mode sequence. The difference between the corresponding data points in the axial strain sequence and the intrinsic mode sequence is used as the residual sequence, and the residual sequence is used as the target axial strain sequence. Based on the maximum and minimum points in the target axial strain sequence, spline interpolation is performed on the maximum and minimum points respectively to obtain multiple target intrinsic mode sequences. Based on the reference period corresponding to each test frequency, the dominant frequency intrinsic mode sequence is determined from the target intrinsic mode sequence to construct the fundamental component signal.

6. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 1, characterized in that, The envelope amplitude sequences of adjacent measurement sections are differentially calculated to obtain an envelope difference sequence. A rectangular integral is then performed on the envelope difference sequence to obtain the integration area. The quotient of the integration area and the number of periods contained within the time window is used as the difference parameter for the adjacent measurement sections, including: The two envelope amplitude sequences of adjacent measurement sections are respectively denoted as the first amplitude sequence and the second amplitude sequence, and the difference between the data points in the first amplitude sequence and the corresponding data points in the second amplitude sequence is taken as the envelope difference sequence; The product of the sum of multiple data points in the envelope difference sequence within the time window and the preset sampling time interval is used as the integration area; The number of cycles within the time window is calculated, and the quotient of the integral area and the number of cycles is used as the difference parameter of the adjacent measurement sections.

7. The method for testing the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles according to claim 1, characterized in that, The differential parameters are converted into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles. These axial force differences are then converted into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections. The product of the differential parameter corresponding to each test frequency, the cross-sectional area of ​​the sheet pile, and the elastic modulus of the sheet pile is used as the axial force difference value corresponding to each test frequency. The ratio of the axial force difference corresponding to each test frequency to the outer surface area of ​​the sheet pile between adjacent measurement sections is taken as the local dynamic side resistance strength of adjacent measurement sections at each test frequency, and the average value of the local dynamic side resistance strength corresponding to each test frequency is taken as the dynamic side resistance strength at each test frequency.

8. A testing device for the dynamic lateral resistance strength of soil in vibratory pile driving of steel sheet piles, characterized in that, include: The acquisition module is used to obtain the embedment depth and shear wave velocity of the target soil layer; The determination module is used to calculate the natural frequency based on the embedment depth and the shear wave velocity, and determine multiple test frequencies in combination with multiple preset frequency step sizes. During the single continuous sinking of the steel sheet pile, the multiple test frequencies are switched sequentially to apply excitation force to the steel sheet pile according to each test frequency, and to obtain the time domain signal when all three measurement sections of the steel sheet pile enter the target soil layer. The calculation module is used to calculate the axial strain sequence of each measurement section based on the time-domain signal, perform mode separation on the axial strain sequence using empirical mode decomposition to obtain multiple target intrinsic mode sequences, and determine the fundamental component signal based on the reference period corresponding to each test frequency. The fitting module is used to perform polynomial fitting on the fundamental component signal to obtain a corrected strain sequence, and to extract the envelope of the corrected strain sequence within a preset time window to obtain the envelope amplitude sequence of each measurement section. The calculation module is also used to perform differential calculation on the envelope amplitude sequence of adjacent measurement sections to obtain an envelope difference sequence, perform rectangular integration on the envelope difference sequence to obtain the integration area, and use the quotient of the integration area and the number of periods contained in the time window as the difference parameter of the adjacent measurement sections. The conversion module is used to convert the differential parameters into axial force differences based on the cross-sectional area and elastic modulus of the sheet piles, convert the axial force differences into dynamic side resistance strength at each test frequency based on the outer surface area of ​​the sheet piles between adjacent measurement sections, and take the minimum dynamic side resistance strength as the target dynamic side resistance strength of the target soil layer.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the method for testing the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, enables the testing method for the dynamic lateral resistance strength of soil during vibratory pile driving of sheet piles as described in any one of claims 1 to 7.

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