Foundation ramming control method and control system

Abstract

This invention discloses a method and system for controlling foundation settlement, belonging to the field of foundation treatment and intelligent construction technology. It includes: constructing a regression model of the normalized settlement index and equivalent mechanical parameters of the foundation through calibration experiments; acquiring the single settlement amount and impact energy of each compaction blow in real time and calculating the normalized settlement index; substituting the values ​​into the regression model to retrieve the equivalent mechanical parameters of the foundation; calculating the ratio of mechanical parameters between two adjacent blows as a geological mutation index; determining whether the current foundation is soft, hard, or normal based on dual thresholds; automatically calculating and outputting the energy for the next compaction blow based on the determination result; and incorporating intelligent control strategies such as continuous energy enhancement for soft ground, emergency shutdown for excessively hard ground, and sliding average hammer withdrawal. This invention achieves automated stratum identification and closed-loop adaptive control of compaction energy during dynamic compaction construction, significantly improving the consistency of foundation treatment quality and construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of foundation reinforcement technology, specifically to a foundation settlement control method and control system. Background Technology

[0002] Dynamic compaction (DCM) is an effective method for improving the bearing capacity of loose foundations and eliminating settlement in foundation treatment. Settlement (the amount of settlement caused by a single compaction blow) is a key parameter for evaluating the compaction effect and determining termination conditions. Traditional manual measurement methods (such as levels and measuring rods) suffer from low efficiency, large human error, and inability to provide real-time feedback.

[0003] In recent years, some technical solutions for automatically measuring compaction settlement have emerged. For example, Chinese patent application CN202410262569.9, entitled "Method for Monitoring the Compaction Settlement of Dynamic Compaction Foundation Using Multi-element Induction," discloses an automatic measurement and control system for foundation treatment compaction settlement. This system deeply integrates the AA process (Auto Alignment) with laser ranging technology. It achieves automatic alignment by recognizing target point deviation through image recognition and driving a fine-tuning motor. Simultaneously, it incorporates environmental temperature and humidity compensation to correct the laser ranging value, improving the accuracy of single-blow compaction settlement measurement to ±0.2mm. The system also includes modules for moving average filtering, cumulative compaction settlement statistics, calculation of the average compaction settlement of the last two blows, and over-threshold audible and visual alarms. This achieves automatic acquisition, calculation, storage, and alarm functions for compaction settlement, effectively overcoming the shortcomings of insufficient accuracy and poor real-time performance in manual measurement and traditional automatic measurement.

[0004] However, the aforementioned existing technologies still have the following shortcomings: Lack of ability to identify changes in foundation geological conditions: In actual construction, the foundation often contains weak interlayers (such as soft clay and silty soil) or hard crust layers (such as dense sand layers and old clay layers). These geological abrupt changes can cause abnormal fluctuations in settlement under the same compaction energy. This technology cannot identify such geological changes and is prone to misjudging large settlement caused by weak interlayers as "qualified convergence" or small settlement caused by hard crust layers as "under-compaction," thereby causing construction quality accidents or energy waste.

[0005] The compaction energy cannot be dynamically adjusted: This technology uses a fixed baseline energy for continuous compaction, and the decision to terminate the compaction is based solely on whether the average settlement of the last two blows falls below a fixed threshold (e.g., 50mm). When weak interlayers appear in the foundation, the energy needs to be increased to penetrate the soft layer and achieve an effective reinforcement depth; when a hard shell layer appears in the foundation, excessive energy can cause energy reflection, equipment damage, or even destroy the existing hard shell. This technology lacks the ability to adjust the compaction energy in real time according to geological conditions, resulting in low energy utilization, poor construction efficiency, and uneven quality.

[0006] Lack of closed-loop control for construction quality: Although the technology can record the settlement of a single point, it still requires manual inspection or load test after construction to verify the reinforcement effect, and it cannot optimize parameters in real time during construction. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a foundation settlement control method and control system.

[0008] The technical solution of this invention is: a method for controlling foundation settlement, comprising: A calibration experiment was conducted to construct a regression model between the normalized settlement index and the equivalent mechanical parameters of the foundation. During the compaction of the foundation, the amount of compaction per impact is obtained for each impact, and the impact energy corresponding to that impact is also obtained. The normalized settling index for each impact is calculated based on the single settling amount and impact energy. Substitute the normalized compaction index into the regression model to obtain the corresponding foundation equivalence parameters. The geological abruptness index of the impacted area was obtained based on the equivalent mechanical parameters of the foundation. The geological mutation index is used to determine whether the current foundation is a soft stratum, a hard stratum, or a normal stratum. Calculate the impact energy for the next compaction based on the judgment result, and perform the next compaction according to the calculated impact energy.

[0009] According to the present invention, a method for controlling foundation settlement includes constructing a regression model of the normalized settlement index and equivalent foundation mechanical parameters. This method comprises: conducting calibration experiments in a typical geological area, and constructing a regression model of the normalized settlement index and equivalent foundation mechanical parameters according to the following formula. in: q c —Equivalent mechanical parameters of the foundation; k —Empirical coefficients for calibration in the first region; m —Empirical coefficients for calibration in the second region; I — Normalized settling index, which is the settling displacement produced per unit of impact energy.

[0010] According to the present invention, a method for controlling foundation settlement by compaction includes obtaining the geological abrupt change index of the compaction area based on the equivalent mechanical parameters of the foundation, comprising calculating the geological abrupt change index of the compaction area according to the following formula. in: ——No. iGeological mutation index of the secondary impact area; ——No. i The equivalent mechanical parameters of the foundation after one compaction; ——No. i-1 The equivalent mechanical parameters of the foundation after one compaction.

[0011] According to a foundation settlement control method provided by the present invention, the method for determining whether the current foundation is a weak stratum, a hard stratum, or a normal stratum based on a geological abrupt change index includes: if the geological abrupt change index of the current compaction area does not exceed a first preset value, then the current foundation is determined to be a weak stratum; if the geological abrupt change index of the current compaction area is greater than the first preset value and less than a second preset value, then the current foundation is determined to be a normal stratum; if the geological abrupt change index of the current compaction area is not less than the second preset value, then the current foundation is determined to be a hard stratum; the first preset value is less than 1, and the second preset value is greater than 1.

[0012] According to a method for controlling foundation settlement provided by the present invention, the method for calculating the compaction energy of the next compaction based on the determination result includes: calculating the compaction energy of the next compaction according to the following formula. in: —The impact energy of the next tamping blow; —Design benchmark impact energy; —Adjustment factor: 1 for normal strata, and equal to [value missing] for weak strata. 1+α The value of the hard layer is equal to 1- α ,in α It is a preset constant between 0 and 1.

[0013] According to the foundation settlement control method provided by the present invention, the absolute value of the difference between the adjustment coefficients of two adjacent compaction blows in the same compaction area does not exceed the adjustment threshold; the adjustment threshold is less than 1.

[0014] According to the foundation settlement control method provided by the present invention, if the determination result of n consecutive tampings in the same tamping area is weak stratum, then based on the calculated tamping energy of the (n+1)th tamping, the tamping energy is increased by a preset fixed energy increment until the tamping energy reaches the maximum allowable energy.

[0015] According to the foundation settlement control method provided by the present invention, if the single settlement amount of the current compaction is less than a set lower limit, and the geological abrupt change index corresponding to the current compaction is greater than a third set value, then it is determined that the stratum in the current compaction area is too hard, the compaction is stopped and an alarm message is output; the third set value is greater than a second set value.

[0016] According to the foundation settlement control method provided by the present invention, when the number of tamping blows is not less than two, the average value of the current tamping settlement and the previous tamping settlement is compared with a preset tamping settlement threshold. If the average value is less than the preset tamping settlement threshold, it is determined that the current area tamping settlement has ended and the tamping is stopped.

[0017] This invention also relates to a foundation settlement control system, wherein the control system operates using the aforementioned foundation settlement control method, comprising: The settlement measurement module is used to obtain the settlement amount of each tamping blow. The data storage module is used to store the design baseline impact energy, the first region calibration empirical coefficient, the second region calibration empirical coefficient, and preset threshold parameters; The compaction index calculation module is used to calculate the normalized compaction index. The geological inversion module is used to invert the equivalent mechanical parameters of the foundation based on the regression model. The geological identification module is used to calculate the geological abrupt change index and determine whether the strata are soft, hard, or normal based on the threshold range. The energy regulation module is used to determine the energy adjustment coefficient based on the judgment result, calculate the energy of the next tamping blow, and output the energy control signal to the tamping equipment.

[0018] The advantages of this invention are as follows: 1. This invention relates to a method for controlling foundation settlement. The control method of this invention establishes a complete closed-loop logic chain from physical quantity measurement to mechanical parameter inversion, then to intelligent stratum determination, and finally to energy adaptive regulation. This invention uses a laser rangefinder to obtain the settlement amount in a single run, replacing the traditional method of manually setting up a level and using a steel tape measure. This not only eliminates manual reading errors and response delays, but also makes continuous, high-frequency data acquisition possible, providing an automated data flow foundation for subsequent real-time calculations.

[0019] The entire foundation compaction construction requires no human intervention. Data analysis is completed and instructions for the next hammer blow are output the instant the hammer hits the ground, achieving true control as compaction progresses.

[0020] Traditional methods only consider the superficial data of compaction settlement, while this invention introduces a normalized compaction settlement index and regresses it to the equivalent mechanical parameters of the foundation. The system is no longer a simple threshold switch, but has the ability to perceive the soil's intrinsic mechanical properties by inferring the compaction settlement. It simulates the brain process of geotechnical engineers judging soil quality based on settlement curves.

[0021] This invention defines a geological mutation index and uses this index to identify weak, hard, and normal strata, giving the system advanced sensing capabilities. Before the tamping hammer has fully penetrated the soil layer or reached the stopping criteria, the system has already predicted the nature of the underlying layer based on the longitudinal mutation of mechanical parameters, thereby adjusting the strategy in advance and avoiding blindly compacting weak interlayers, which could lead to the failure of the rubber soil, or wasting energy on hard layers.

[0022] 2. This invention constructs a regression model between the normalized settlement index and the equivalent mechanical parameters of the foundation. This model algorithm is not a rigid, fixed formula, but rather a framework that supports self-learning calibration. For different construction sites, only a small number of calibration experiments are needed to fit the regional calibration empirical coefficients, and the automated control program can be seamlessly transferred to new construction sites, possessing the characteristics of model fine-tuning in machine learning.

[0023] By employing an explicit power function form, the computational complexity is extremely low. Within the very short intervals of compaction (typically only a few seconds), the industrial controller can instantly complete the exponential calculation and derive the foundation mechanical parameters. This lightweight mathematical model is the key physical foundation for ensuring smooth and lag-free real-time automated control.

[0024] 3. This invention defines a geological abrupt change index and uses a ratio method for differential detection, an extremely sensitive digital signal processing technique. In the field of automation control, relative changes are often more valuable for early warning than absolute changes. The system does not need to know the specific classification of the soil; it only needs to sense a jump in mechanical parameters to determine that it has entered a different stratum. This gives the equipment an automated visual capability to identify lithological interfaces.

[0025] By employing a self-comparison method using before-and-after ratios, systematic absolute measurement errors caused by laser sensor temperature drift and hammer eccentricity are effectively offset. Even if the absolute values ​​of the foundation's equivalent mechanical parameters are slightly off, as long as the directions of adjacent deviations are consistent, the geological mutation index can still accurately reflect the trend of strata changes. This is a key design feature that ensures the stability of automated equipment during long-term field operations.

[0026] 4. This invention constructs a hysteresis comparator logic with a dead zone by setting an interval where the first setpoint < 1 < the second setpoint. This means that minor inhomogeneities in the formation will not cause frequent jumps and oscillations in the control system. Directly mapping continuous physical quantities (ratios) to discrete control command categories (weak / normal / hard) is typical state machine logic, which is beneficial for programming to implement automated sequential control.

[0027] 5. This invention achieves real-time matching between input energy and foundation impedance. This is the ultimate goal of intelligent dynamic compaction construction—on-demand energy supply. For soft soil, it automatically increases energy to overcome resistance and accelerate drainage and consolidation; for hard soil, it automatically reduces energy to prevent excessive rebound of the tamper hammer from damaging the machinery and to save fuel. This design ensures that automated adjustments do not deviate too far from the design drawings, leveraging the flexibility of intelligent control while ensuring the safety of the project.

[0028] 6. By setting the control logic that the absolute value of the difference between two adjacent adjustment coefficients does not exceed the adjustment threshold, the present invention makes the energy change curve smoother, reduces the acceleration change of the servo motor of the equipment, and reflects the intelligent protection of the life and stability of the actuator.

[0029] 7. After n consecutive weak soil determinations, this invention adds a fixed increment to the existing foundation until the upper limit is reached. This is equivalent to determining that the soil in the area is relatively soft and requires increased compaction energy, which can accelerate the efficiency of foundation treatment, reduce the number of compaction cycles, and make foundation compaction more intelligent.

[0030] 8. This invention establishes a dual-judgment trigger shutdown alarm system. Only when the surface symptoms (unable to compact, little subsidence) and the underlying mechanism (sudden increase in mechanical parameters) are consistent is the formation determined to be too hard. This significantly reduces the probability of erroneous shutdowns while ensuring that truly dangerous conditions (forced hammering could cause the hammer to break and fly out) can be automatically identified and power cut off in an emergency, thus improving construction safety.

[0031] 9. This invention stops hammering when the average settlement of the current and previous compaction operations is less than a threshold. It uses a moving average filter instead of a single value determination because, during dynamic compaction, the settlement of a single compaction operation may fluctuate due to local surface unevenness. If only the last compaction is considered, the system might incorrectly determine the end of the operation before the soil has become dense. By taking the average value, the system automatically filters out high-frequency noise interference, making the decision to stop hammering more scientific and accurate, and ensuring the uniformity of the foundation treatment quality.

[0032] 10. This invention also relates to a control system, wherein the measurement module is the sensor, the inversion and recognition module is the brain, and the control module is the hands and feet. It is not merely a software algorithm, but an automated edge computing terminal that can be embedded in the controller, directly replacing manual operators and on-site supervisors, significantly improving the unmanned and intelligent level of dynamic compaction construction. Attached Figure Description

[0033] Figure 1 : Schematic diagram of the control method of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0038] This invention relates to a foundation compaction control method, which operates in an embedded industrial controller installed on a dynamic compaction machine. The controller is electrically connected to a high-precision laser rangefinder installed on the boom or independent support of the compaction machine, an encoder installed on the winch or unhooker, and a frequency converter or hydraulic proportional valve for controlling the lifting height of the hammer.

[0039] In actual operation, such as Figure 1 As shown, the control method steps include: Step S101: Calibration and modeling stage.

[0040] Before commencing formal large-scale foundation compaction construction, a representative geological area is selected for on-site calibration experiments. The geological conditions of this area must encompass the main soil types of the foundation to be treated. Within this area, multiple sets of test compactions with different energies and number of blows are conducted. During the test compactions, in-situ testing equipment such as a static cone penetration test (CPT) or a pressure gauge are used to simultaneously determine the equivalent mechanical parameters of the foundation soil after each blow. q c (For example, cone tip resistance or deformation modulus). Simultaneously, record the impact energy corresponding to each blow. E and cumulative settlement (or single settlement)Δs Using the collected discrete data, a normalized settling index was constructed through mathematical regression analysis. I Equivalent mechanical parameters of foundation q c The functional relationship model between them, i.e. q c = f(I) The model is stored in the controller's data storage module.

[0041] Step S102: Real-time data acquisition stage.

[0042] During the formal compaction operation of the foundation, the controller executes an automatic data acquisition cycle.

[0043] Accumulation of settling volume: Before each hammer strike is released and falls, a laser rangefinder emits a laser beam to a reference point at the top of the hammer to record the initial height. H i-1 After the tamping hammer lands, completes its impact, and comes to a stop, the height is measured again. H i The controller calculates the difference. Δs i = H i-1 -H i Automatically obtain the first i Single compaction volume per impact Δs i .

[0044] Impact energy acquisition: The actual lifting height of the ram is obtained by reading the encoder data that controls the lifting of the ram. ℎ i and known hammer mass M Calculate the impact energy corresponding to this impact. E = M·g·h i .

[0045] Step S103: Normalization and Inversion Stage.

[0046] The controller calls the settlement index calculation module, based on the single settlement amount obtained in step S102. Δs i and impact energy E i Calculate the first i Normalized subsidence index of the second impact I i This index is defined as the ratio of the amount of compaction in a single run to the corresponding energy, and is used to eliminate the influence of energy differences on the absolute value of the compaction amount.

[0047] Subsequently, the controller invokes the geological inversion module to calculate the... Ii Substitute into the regression model established in step S101 q c,i = f(I i ) In the middle, obtain the current position of the tamping point. i The equivalent mechanical parameters of the foundation corresponding to the second compaction. q c,i .

[0048] Step S104: Stratigraphic abrupt change analysis stage.

[0049] The controller calls the geological identification module to read the mechanical parameters of the current compaction. q c,i Mechanical parameters of the previous impact q c,i-1 Calculate the geological abrupt change index of the area affected by this ramming. G i This index reflects the instantaneous change gradient of the underlying soil's mechanical properties in the vertical direction as the number of compaction blows increases.

[0050] Step S105: Formation state determination stage.

[0051] The controller, based on preset logic thresholds and the geological mutation index, G i Determine the type of the current foundation. For example, determine whether it is a weak stratum (such as a lens of silty soil), a hard stratum (such as a lens of gravel), or a normal stratum (homogeneous soil properties).

[0052] Step S106: Energy adaptive regulation stage.

[0053] The controller invokes the energy regulation module, and based on the determination result of step S105, executes the corresponding energy adjustment strategy to calculate the next (the...) energy adjustment time. i Optimal impact energy for (+1) impacts E i+1 The controller then generates a control signal to drive the lifting mechanism of the compaction equipment, according to the calculated energy value. E i+1 The hammer drop height is automatically adjusted for the next tamping strike.

[0054] Step S107: Execute repeatedly.

[0055] Repeat steps S102 to S106 until the preset hammer stop criteria are met.

[0056] The control method of this invention establishes a complete automated closed-loop link from physical perception to intelligent decision-making. Its principle lies in using the decay law of compaction settlement with energy to characterize soil stiffness. The advantages of intelligence are: the system simulates the process of geotechnical engineers' diagnostic work, deducing three-dimensional changes in foundation mechanical properties from one-dimensional settlement data, thus realizing the substitution of perception for experience. The advantages of automation are: from data acquisition, calculation, and judgment to command issuance, everything is completed autonomously by the machine, with a response speed reaching the second level, eliminating the lag and dispersion of manual measurement, and truly realizing real-time dynamic control of dynamic compaction construction.

[0057] In some embodiments of the present invention, this embodiment specifically defines the method for constructing a regression model of the normalized settlement index and the equivalent mechanical parameters of the foundation in step S101.

[0058] When conducting calibration experiments in typical geological areas, static cone penetration tests are used to obtain the cone tip resistance of soil layers at different depths. q c This serves as a reference standard value for the equivalent mechanical parameters of the foundation. For each test compaction blow count... j Record the corresponding impact energy E j and the amount of single compaction produced Δs j .

[0059] Normalized tamping index I The calculation formula is determined as follows: in, Δs The unit is millimeters (mm). E The unit is kilojoules (kJ). The physical meaning of this formula is the settlement displacement generated per unit of energy, which directly reflects the soil's ability to resist impact deformation.

[0060] By analyzing multiple groups ( I, q c Curve fitting of the data points revealed a significant linear relationship between the two in a double logarithmic coordinate system. Therefore, the following nonlinear regression model was constructed: By using the least squares method or similar mathematical optimization algorithms, the measured data are fitted to obtain the first-area calibration empirical coefficients for this specific construction area. k Second region calibration empirical coefficient m . k This represents the baseline strength level of the soil under unit energy. m It represents the sensitivity index of compaction energy to soil strength.

[0061] Algorithm Supplement and Automated Implementation: In the software implementation of the automation controller, the recursive least squares method is used to determine the parameters. k and m Online identification. The specific steps are as follows: 1. Initialize the parameter vector .

[0062] 2. Take the natural logarithm of both sides of the equation: .

[0063] 3. Each time a new set of data is acquired ( I i ,q c ,i ), calculate the gain matrix and update θ .

[0064] 4. Once the amount of calibration experimental data reaches a preset threshold (e.g., 20 sets of valid data), stop the recursion and lock the data. k and m The value is then stored in the database for subsequent real-time inversion calls.

[0065] The model in this embodiment is based on the energy decay principle of dynamic penetration testing. As the soil hardens, the penetration depth (settlement) produced by the same amount of energy decreases exponentially.

[0066] The model in this embodiment k and m As trainable parameters, this gives the algorithm regional adaptability. Unlike devices with fixed parameters, this method can automatically extract the geological fingerprint features of the construction site through short-term on-site calibration, demonstrating the transferability of machine learning.

[0067] The algorithm in this embodiment only involves power function operations, with extremely low computational load. It is fully compatible with the limited computing resources of industrial-grade microcontrollers or PLCs, ensuring that real-time online calculations are completed within a 10-20 second tamping interval without causing control delay.

[0068] In other embodiments of the present invention, this embodiment specifically defines the method for obtaining the geological mutation index of the compaction area based on the foundation equivalent mechanical parameters in step S104.

[0069] The controller internally maintains a first-in-first-out queue of at least length 2 to store the foundation equivalence mechanical parameters obtained from the two most recent calculations. q c,i-1 and q c,i .

[0070] Number of tampings i When ≥2, the geological identification module calculates the first...i Geological mutation index in the secondary impact area G i : in: ——No. i Geological mutation index of the secondary impact area; ——No. i The equivalent mechanical parameters of the foundation after the second compaction, or in other words, the first compaction. i Inversion strength of the foundation after the second compaction; ——No. i-1 The equivalent mechanical parameters of the foundation after the second compaction, or in other words, the first compaction. i -1 foundation inversion strength after compaction.

[0071] To eliminate computational glitch caused by sensor noise and micro-inhomogeneities in the soil layer, the original [data / material] was processed before calculating the ratio. q c The sequence is processed by first-order hysteresis filtering: Where γ is the filtering coefficient, typically taken as 0.6 to 0.8. The filtered data is then used in… calculate.

[0072] This embodiment utilizes the characteristic in geotechnical engineering that the effective influence depths of two adjacent impacts highly overlap and the depth increment is small. If the soil is homogeneous, the inversion intensity of two consecutive impacts should be basically the same. G≈1 If a sudden change occurs, it must be due to a change in the geological strata.

[0073] This embodiment presents an edge computing strategy based on differential detection. It does not require a large geological database to support the classifier; anomalies can be identified solely by the relative rate of change of the signal itself. This endows the system with rudimentary intelligence of self-comparison and self-reference, effectively offsetting common-mode errors caused by long-term sensor drift or changes in ambient temperature. The calculation process involves only a single division operation, making it extremely suitable for implementing high-frequency triggered interrupt service routines in resource-constrained embedded systems, ensuring the immediacy of the judgment.

[0074] In a preferred embodiment of the present invention, the method for determining the current foundation type in step S105 is specifically defined.

[0075] Detailed description of control methods: Two key discrimination thresholds are preset in the controller's data storage module: the first set value TH 1 Second setting value TH 2Based on extensive engineering experience, the following settings are established: TH 1 The value range is [0.70, 0.90], preferably 0.85; set TH 2 The value range is [1.10, 1.40], and preferably 1.20.

[0076] The decision logic executes the following conditional branch: Condition 1 (weak strata): If ≤ TH 1 If so, the soil beneath the current tamping hammer is determined to be a weak stratum relative to the location of the previous impact. For example, =0.80 indicates a sudden 20% drop in strength, meaning that the hammer has penetrated the hard shell layer and entered the weak underlying layer.

[0077] Condition 2 (Normal Formation): If TH 1 < < TH 2 If so, the current foundation is determined to be a normal stratum. This indicates that the soil properties fluctuate within the range of statistical error and normal soil compaction.

[0078] Condition 3 (Hard strata): If ≥ TH 2 If the condition is met, the current foundation is determined to be a hard stratum. This indicates that the tamping hammer encountered an isolated boulder, a hard lens, or entered the bearing layer.

[0079] This embodiment simulates the principle of a hysteresis comparator or Schmitt trigger in control theory. By setting asymmetrical dead zones on both sides of 1, frequent switching caused by a single threshold is avoided.

[0080] The mechanical parameters of natural soil layers always exhibit slight fluctuations. If a rigid criterion of exactly 1 is used, the system will fall into a cycle of soft, hard, and soft oscillations. A dual-threshold interval provides the system with a degree of insensitivity, making its behavior more like that of an experienced operator—responding only when changes are significant. This logical division maps continuously changing physical quantities to a finite set of deterministic state enumeration values, providing clear and stable state machine switching conditions for the lower-level program, facilitating the writing of highly reliable embedded C language code.

[0081] In a further embodiment of the present invention, this embodiment specifically defines the method for calculating the impact energy of the next impact in step S106.

[0082] The system presets a design benchmark compaction energy determined by geotechnical engineering design drawings. E 0(Unit: kN·m). Based on the determination result of step S105, the energy regulation module queries the energy adjustment coefficient mapping table to determine the current adjustment coefficient. β i The mapping relationship is as follows: If it is a normal stratum β i =1; If it is a weak stratum β i =1+α; If it is a hard layer β i =1-α; Here, α is a preset constant between 0 and 1, also known as the radical factor. In this embodiment, α is preferably set to 0.15.

[0083] You can also obtain it using the following table. β i . The impact energy of the next tamping blow E i+1 The calculation formula is: When the control program executes this algorithm, it must include upper and lower limit logic.

[0084] This embodiment is based on the principle of energy matching. Soft soil has high compressibility, requiring additional energy to overcome its viscous resistance and accelerate the dissipation of pore water pressure; hard soil has high stiffness, and excessive energy will cause the tamper to rebound violently and waste mechanical work.

[0085] This embodiment achieves dynamic matching between energy supply and foundation impedance. α The introduction of values ​​reflects the adjustability of the intelligent strategy, allowing for flexible adjustments based on different engineering risk preferences (such as conservative or high-efficiency). Energy regulation is achieved through linear mapping, and control commands are generated extremely quickly. Frequency converters or hydraulic proportional valves can respond directly. E i+1 The command enables stepless automatic adjustment of the hammer drop distance, replacing the crude operation mode of manually inserting and removing limit pins.

[0086] In a further embodiment of the present invention, this embodiment adds a smooth constraint mechanism to prevent drastic energy fluctuations, based on the previous embodiment.

[0087] To avoid a sudden jump in the energy setpoint between two compaction blows due to instantaneous disturbances in the geological mutation index calculation (e.g., a jump from 100% energy to 70% instantaneously), the controller is equipped with an adjustment threshold. Δβ maxThe threshold is less than 1, and in this embodiment it is preferably 0.20.

[0088] After calculating the number i+1 Theoretical adjustment coefficient for this time After that, it is not output directly, but is combined with the first... i Adjustment coefficient for the actual implementation Comparison: Calculate the absolute value of the difference: like δ > Δβ max Then the ramp limiting algorithm will be executed: Final impact energy .

[0089] In automated control, limiting the rate of change is a necessary means to protect the inertial load of the actuator. This embodiment provides the system with an intelligent strategy for smooth transition. It avoids the instantaneous stress wave disturbance to the surrounding soil caused by sudden energy changes, which is beneficial to protecting nearby underground pipelines or buildings. It directly protects the hoist motor, wire rope, and clutch of the dynamic compaction machine. Excessive acceleration commands can cause the motor current overload protection to trip. This embodiment significantly extends the mechanical life and electrical stability of the automated actuator through algorithm-level softening.

[0090] In other embodiments of the present invention, this embodiment adds a cumulative compensation strategy for the special working conditions of thick soft clay.

[0091] The controller internally maintains a continuous counter for weak formations. C soft .

[0092] Each time a weak stratum is identified, C soft Add 1; if it is determined to be a non-weak stratum, then C soft Reset to zero.

[0093] when C soft When the number of iterations is greater than or equal to n (where n is a preset threshold number of iterations, for example, n=3), the system determines that it has encountered a weak interlayer with a certain thickness, and it is difficult to pass through quickly by simply adjusting the ratio (1+α).

[0094] At this point, the system activates a forced incremental strategy. The calculated energy of the (n+1)th impact is... E n+1 On top of that, an additional preset fixed energy increment is added. ΔE fixed (e.g., 200 kN·m): Continue to increase the impact energy until it reaches the maximum permissible energy allowed by the equipment. E max Or the stratigraphic determination results may change.

[0095] This embodiment is based on the compaction and replacement principles in soil mechanics. For highly sensitive soft soil, continuous low-energy hammering will cause the spring soil effect, and the soil cannot effectively drain and consolidate; high-energy impact must be used to destroy its structure and form drainage channels.

[0096] This embodiment formalizes and codifies the emergency response experience of senior geotechnical experts. Conventional PID algorithms are prone to failure in such nonlinear time-varying systems, while this solution, based on expert system rules and variable structure control, simulates the decision-making process of a human operator determining that the ground is too soft and requires aggressive intervention. It achieves automated intervention under special conditions, preventing the automatic control system from falling into an ineffective loop due to its inability to penetrate weak layers, thus ensuring the automated progress of the construction schedule.

[0097] In a further embodiment of the present invention, this embodiment adds an emergency shutdown protection mechanism for excessively hard formations, based on the above embodiment.

[0098] Two additional parameters are preset in the controller: the lower limit threshold of the compaction amount. S min (e.g., 10mm) and the third setting value TH 3 (Upper limit alarm value for geological sudden changes, for example) TH 3 =2.0).

[0099] After each execution of steps S102 and S104, the system performs the following logic and judgment: if the single compaction amount is less than the set lower limit... S min And the corresponding geological mutation index is greater than the third set value. TH 3 If the current stratum in the compaction area is determined to be too hard, compaction is stopped and an alarm message is output; the third set value TH 3 Greater than the second set value TH 2 .

[0100] This embodiment employs a logic locking mechanism that verifies both appearance and mechanism. A small single compaction amount may be due to the soil becoming denser as the number of hammer blows increases, in which case the machine should not be stopped; only when the compaction amount is extremely small and the mechanical parameters show a sudden surge can it be confirmed that the rigid boundary has been reached.

[0101] This embodiment significantly improves the accuracy and confidence of fault diagnosis, effectively avoiding unintended shutdowns caused by abnormal data from a single sensor, and possesses a certain degree of fault-tolerant intelligence. This is the highest level of safety interlock for unmanned operation of dynamic compaction machines. Forcibly hammering hard rock with high energy can lead to serious mechanical accidents such as hammer cracking and wire rope breakage. This embodiment can automatically cut off power within milliseconds before an accident occurs, ensuring the inherent safety of automated unmanned construction sites.

[0102] In some embodiments of the present invention, this embodiment provides an intelligent hammer-collection judgment method based on moving average filtering.

[0103] The conventional standard for stopping hammer blows is that the average settlement of the last two blows is less than a threshold, but manual measurement is often lagging. This embodiment achieves this in an automated process as follows: Number of tampings i When ≥2, calculate the moving average: Will With the preset hammer stop threshold S stop (For example, 50mm) for comparison. If ≤ S stop If the controller determines that the current compaction point has reached the design density requirement, it sends a compaction completion signal, automatically stops compacting at that point, and prompts the user to move to the next compaction point.

[0104] This embodiment utilizes an averaging algorithm to filter out random impact noise. It simulates the subconscious tendency of supervising engineers to ignore occasional fluctuations when reading settlement gauges. This avoids misjudgments caused by abnormally large or small settlement readings due to localized liquefaction of surface sand or the lifting of stones. It achieves unmanned and standardized settlement decision-making. The settlement criteria determined by the algorithm are more stringent and consistent than manual visual gauge readings, ensuring the uniformity of the overall foundation treatment quality and eliminating quality risks caused by human factors.

[0105] Specifically, the foundation settlement control method of the present invention is carried out according to the following steps: Phase 1: On-site initialization and calibration The system performs a self-test upon startup, and the operator inputs the design benchmark compaction energy through the human-machine interface. E 0 Perform test compaction at 3-5 points in a corner of the construction area. The system automatically records each compaction blow. Δs and E It also prompts the operator to manually input the CPT cone tip resistance for the corresponding number of blows. q cData. After clicking the "Start Calibration" button, the system calls the recursive least squares algorithm to automatically fit the data. In k and m The coefficients are then stored in the data storage module.

[0106] Phase Two: Automated Cyclic Single-Point Impacting For each official tamping point, the system resets the counter and executes the following loop: First strike: with baseline energy E 0 Make the first strike.

[0107] Measurement module obtains compaction amount Δs 1 ,calculate I 1 Inversion module calculation q c,1 .

[0108] Due to the lack of preceding data, stratigraphic determination is not performed; the default is... E 0 Perform the second attack.

[0109] The second hit and subsequent cycles (starting from the second hit) i For example, i ≥2): Data acquisition: After the hammer hits the ground, the laser rangefinder acquires data. Δs i encoder acquisition E i .

[0110] Calculation index: Calculation ∆s i / E i .

[0111] Mechanical inversion: calculation .

[0112] Mutation analysis: calculation .

[0113] Safety monitoring: If Δs i <S min and G i >TH 3 The machine was shut down immediately and an alarm was triggered.

[0114] Stratigraphic determination: If G i If the value is ≤0.85, set the state to Soft (weak strata).

[0115] If 0.85 < G i <1.20, set the state to Normal (normal formation).

[0116] like G i ≥1.20, set the state to Hard (hard layer).

[0117] Energy Decisions: Determine the basic adjustment coefficient based on the status. β base (Soft:1.15;Normal:1.00;Hard:0.85).

[0118] Check and execute the ramp limiting logic to ensure that the actual β change between two consecutive intervals is less than 0.20.

[0119] Check the soft formation counter. If it reads "Soft" three times in a row, add an extra 200 kN·m of energy.

[0120] Calculate the final E i+1 It also outputs amplitude limiting protection.

[0121] Execution and Feedback: The controller issues a command, and the winch lifts the rammer to the corresponding position. E i+1 Once the required height is reached, the hook is released for the next tamping.

[0122] Hammer retraction judgment: Calculation ( Δs i + Δs i-1 ) / 2. If this value is less than 50mm, exit the loop, complete the compaction operation, and prompt the driver to move the vehicle.

[0123] Through the aforementioned tightly coupled automated process and intelligent algorithm, this invention successfully transforms dynamic compaction operations, which rely on personal experience, into a data-driven, scientifically controllable precision manufacturing process.

[0124] In addition, the present invention also relates to a foundation settlement control system for performing the above-described method.

[0125] The system consists of a vehicle-mounted terminal installed on the dynamic compaction machine and a remote monitoring platform. The vehicle-mounted terminal specifically includes the following modular units: 1. Settlement Measurement Module: Hardware: Phase-type laser rangefinder sensor (accuracy ±1mm), installed on the gantry of the dynamic compaction machine.

[0126] Function: Automatically tracks the top reflector plate of the tamping hammer to obtain elevation data before and after each tamping blow in real time.

[0127] 2. Data storage module: Hardware: Non-volatile flash memory and RAM.

[0128] Storage content: Design baseline impact energy E 0 First region calibration empirical coefficient k Second region calibration empirical coefficient m Preset TH 1 , TH 2 Threshold parameters, and historical construction logs.

[0129] 3. Settlement Index Calculation Module: Function: Retrieve data from the measurement module, according to the formula. I = Δs / E Real-time calculation of the normalized compaction index.

[0130] Geological inversion module: Function: Runs the power function regression algorithm described in the above embodiments, based on... I Real-time output of foundation equivalent mechanical parameters q c .

[0131] Geological identification module: Function: Performs the ratio calculation and logical judgment of the above embodiments, and outputs the formation category label (weak / normal / hard) in real time.

[0132] Energy regulation module: Function: Runs the baseline proportional adjustment algorithm, the ramp limiting algorithm, and the weak layer cumulative compensation algorithm described in the above embodiments. Finally, it generates a standard analog signal (such as a 4-20mA current signal) or CAN bus digital commands.

[0133] 7. Execution and Security Module: It receives instructions from the energy regulation module to drive the hydraulic pilot proportional handle or the winch frequency converter.

[0134] Upon receiving the emergency stop signal from the above embodiment, power is cut off.

[0135] The control method of this invention can be used not only in the field of foundation compaction technology, but also in the field of pile hammer impact pile technology, which includes the compaction treatment principle.

[0136] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling foundation settlement, characterized in that: include: A calibration experiment was conducted to construct a regression model between the normalized settlement index and the equivalent mechanical parameters of the foundation. During the compaction of the foundation, the amount of compaction per impact is obtained for each impact, and the impact energy corresponding to that impact is also obtained. The normalized settling index for each impact is calculated based on the single settling amount and impact energy. Substitute the normalized compaction index into the regression model to obtain the corresponding foundation equivalence parameters. The geological abruptness index of the impacted area was obtained based on the equivalent mechanical parameters of the foundation. The geological mutation index is used to determine whether the current foundation is a soft stratum, a hard stratum, or a normal stratum. Calculate the impact energy for the next compaction based on the judgment result, and perform the next compaction according to the calculated impact energy.

2. The foundation settlement control method according to claim 1, characterized in that: The method for constructing a regression model of the normalized settlement index and the equivalent mechanical parameters of the foundation includes: conducting calibration experiments in typical geological areas, and constructing a regression model of the normalized settlement index and the equivalent mechanical parameters of the foundation according to the following formula. in: q c —Equivalent mechanical parameters of the foundation; k —Empirical coefficients for calibration in the first region; m —Empirical coefficients for calibration in the second region; I — Normalized settling index, which is the settling displacement produced per unit of impact energy.

3. The foundation settlement control method according to claim 1, characterized in that: The method for obtaining the geological abrupt change index of the compaction area based on the foundation equivalent mechanical parameters includes: calculating the geological abrupt change index of the compaction area according to the following formula. in: ——No. i Geological mutation index of the secondary impact area; ——No. i The equivalent mechanical parameters of the foundation after one compaction; ——No. i-1 The equivalent mechanical parameters of the foundation after one compaction.

4. The foundation settlement control method according to claim 1, characterized in that: The method for determining whether the current foundation is a weak stratum, a hard stratum, or a normal stratum based on the geological mutation index includes: if the geological mutation index of the current compaction area does not exceed a first preset value, then the current foundation is determined to be a weak stratum; if the geological mutation index of the current compaction area is greater than the first preset value and less than a second preset value, then the current foundation is determined to be a normal stratum; if the geological mutation index of the current compaction area is not less than the second preset value, then the current foundation is determined to be a hard stratum; the first preset value is less than 1, and the second preset value is greater than 1.

5. The foundation settlement control method according to claim 1, characterized in that: The method for calculating the impact energy of the next compaction based on the judgment result includes: calculating the impact energy of the next compaction according to the following formula. in: —The impact energy of the next tamping blow; —Design benchmark impact energy; —Adjustment factor: 1 for normal strata, and equal to [value missing] for weak strata. 1+α The value of the hard layer is equal to 1-α ,in α It is a preset constant between 0 and 1.

6. The foundation settlement control method according to claim 5, characterized in that: The absolute value of the difference between the adjustment coefficients of two adjacent compaction blows in the same compaction area does not exceed the adjustment threshold; the adjustment threshold is less than 1.

7. The foundation settlement control method according to claim 5, characterized in that: If the results of n consecutive compaction operations in the same compaction area are all weak strata, then the compaction energy will be increased by a preset fixed energy increment based on the calculated energy of the (n+1)th compaction operation, until the compaction energy reaches the maximum allowable energy.

8. The foundation settlement control method according to claim 4, characterized in that: If the single-step settlement of the current compaction is less than the set lower limit, and the geological abrupt change index corresponding to the current compaction is greater than the third set value, then it is determined that the strata in the current compaction area are too hard, the compaction is stopped and an alarm message is output; the third set value is greater than the second set value.

9. The foundation settlement control method according to claim 1, characterized in that: When the number of tamping blows is not less than two, the average of the current tamping amount and the previous tamping amount is compared with the preset tamping threshold. If the average is less than the preset tamping threshold, it is determined that the tamping of the current area has ended and the tamping is stopped.

10. A foundation settlement control system, characterized in that: The control system operates using a foundation settlement control method as described in any one of claims 1 to 9, including: The settlement measurement module is used to obtain the settlement amount of each tamping blow. The data storage module is used to store the design baseline impact energy, the first region calibration empirical coefficient, the second region calibration empirical coefficient, and preset threshold parameters; The compaction index calculation module is used to calculate the normalized compaction index. The geological inversion module is used to invert the equivalent mechanical parameters of the foundation based on the regression model. The geological identification module is used to calculate the geological abrupt change index and determine whether the strata are soft, hard, or normal based on the threshold range. The energy regulation module is used to determine the energy adjustment coefficient based on the judgment result, calculate the energy of the next tamping blow, and output the energy control signal to the tamping equipment.

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