Method for controlling sinking of caisson in water-rich sand layer and disturbance of adjacent building

Abstract

The application discloses a control method for caisson sinking in water-rich sand layer and disturbance of adjacent buildings, which comprises the following steps: based on numerical simulation, stratum parameters are inversed and a hydraulic barrier is pre-designed; the sinking rate and the inclination angle of the caisson are collected in real time, the depth of soil removal or the amount of mud injection is adjusted by an inner ring incremental PID controller, so that the rate and the inclination angle tend to be close to the set value; meanwhile, the active control coefficient K c‑eff (t) is calculated, the rate set value is dynamically adjusted by an outer ring supervisor, and the K c‑eff (t) is ensured to be always in a safe interval; a precipitation settlement calculation model based on the layering summation method is established, and when the cumulative settlement or the settlement rate exceeds the standard, the recharge flow is adjusted according to an incremental formula. Through the "mechanical supervision-rate following" cascade control and the settlement-recharge closed loop feedback, the safe and controllable sinking of the caisson in the water-rich sand layer and the effective protection of the adjacent buildings are realized.

Description

Technical Field

[0001] This invention relates to the field of adaptive control technology, and in particular to a method for controlling the settlement of caissons and disturbances to nearby buildings in water-rich sand layers. Background Technology

[0002] Caissons, as a deep foundation construction technology, are widely used in projects such as water supply and drainage pumping stations, pipe jacking shafts, shield tunneling launching shafts, and bridge anchorage foundations. Water-rich sand layers refer to medium-fine sand and silty sand strata with high groundwater levels and saturated water content. These layers are characterized by high permeability, poor self-stabilization, and a susceptibility to quicksand and piping under hydrodynamic forces. The use of caisson construction methods in water-rich sand layers presents two major technical challenges.

[0003] Firstly, existing caisson sinking control technologies mostly rely on manual experience, adjusting the soil extraction sequence and grouting volume by observing the sinking rate and tilt angle, lacking quantitative perception and closed-loop control of the caisson's stress state. In recent years, some projects have introduced automatic sinking systems based on PID control algorithms, using the actual sinking rate approaching the set rate as the direct control objective, maintaining rate stability by adjusting the soil extraction depth or thixotropic mud injection volume. However, in water-rich sand layers, the well wall friction resistance may fluctuate significantly in a short period due to excessive mud sleeve thickness, localized liquefaction or compaction of the sand layer. When the friction resistance decreases abnormally, even if the sinking rate stabilizes at the set value, the effective sinking force may still far exceed the friction resistance (i.e., the active control coefficient is too large). In this case, the caisson is in a dangerous state of "stress imbalance," and will suddenly sink upon encountering even a slight disturbance. Conversely, when the friction resistance increases abnormally, even at a low rate, a too small active control coefficient can lead to well jamming. Traditional rate PID control cannot detect the above-mentioned mechanical imbalance. Its output command may "blindly" adjust soil extraction or grouting to maintain the rate, which may exacerbate the risk of sudden sinking or well jamming.

[0004] Secondly, there is the issue of disturbance to nearby buildings caused by caisson construction. Caisson construction in water-rich sand layers requires continuous drainage from the caisson to lower the groundwater level and achieve dry working conditions. This drainage process alters the seepage field of the soil surrounding the caisson, creating a head difference between the inside and outside of the caisson. Groundwater seeps towards the caisson, increasing the effective stress in the sand layer and causing consolidation settlement of the soil outside the pit. This settlement effect may affect the foundations of nearby buildings, causing uneven settlement, tilting, or even structural damage. Existing technologies such as grouting reinforcement and isolation piles are costly, time-consuming, and difficult to quantify and control settlement caused by dewatering. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a feedback-controlled caisson construction method for water-rich sand layers, achieving adaptive control of the caisson sinking process and effective suppression of deformation of adjacent structures. The specific solution is as follows: A method for controlling the settlement of caissons and disturbance to adjacent buildings in water-rich sand layers includes the following steps: Step S1: Real-time data acquisition; Step S2: Calculate the wellbore friction F fk (t) and active control coefficient K c (t); Step S3: Set the caisson sinking rate v set Calculate the deviation of the caisson sinking rate e v (t), the incremental PID controller uses e v (t) is the input, and the output control quantity u(t) is the adjustment value Δu(t), where the control quantity u(t) is at least one of mud injection flow rate or soil sampling depth; Step S4: Calculate the effective active control coefficient K after considering the friction reduction of thixotropic mud and the effects of soil removal disturbance, based on the adjustment value Δu(t). c-eff (t), and determine whether it falls within the target interval [K]. c,min ,K c,max If it doesn't fall within the range, adjust v. set To K c-eff (t) falls into the target interval.

[0006] Furthermore, the data collected in step S1 includes: the perimeter U of the outer wall of the caisson, the depth of the caisson into the soil H(t), and the unit frictional resistance value q0 at a depth of 5m.

[0007] Furthermore, F fk The formula for calculating (t) is: Where q0 is the unit frictional resistance value of the caisson sidewall at a depth of 5m, U is the perimeter of the caisson outer wall, and H(t) is the burial depth.

[0008] Furthermore, define the active control coefficient K. c (t) represents the ratio of the actual effective sinking force to the real-time frictional force at the current moment, and the active control coefficient K. c The formula for calculating K(t) is: c (t)=(G k -F fw，k (t)-F add (t) / F fk (t); Among them, G k F represents the standard value of the caisson's self-weight. add (t) represents the surface counterweight or reverse jacking force, where positive values ​​represent jacking and negative values ​​represent counterweight; F fw，k (t) represents the buoyancy force of the water.

[0009] Further, step S3 includes: S31: The control system collects the sinking rate v in real time.实 (t), and the set value v set Calculate the deviation: e v (t) = v set -v 实 (t); S32: The control quantity u(t) is calculated using the incremental PID formula: Δu(t) = K p [e(t)-e(t-1)]+K i e(t)+K d [e(t)-2e(t-1)+e(t-2)], where K p K is the proportionality coefficient. i K is the integral coefficient. d is the differential coefficient.

[0010] Further, step S4 includes: S41: The control quantity Δu(t) output by the inner loop PID is analyzed as the soil sampling depth increment Δd. exc (mm) or thixotropic mud injection flow rate increment ΔQ slurry (L / min); S42: Calculate the effective unit frictional resistance q after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal. eff The calculation formula is as follows: Where q0 is the original unit frictional resistance, λ is the mud friction reduction efficiency coefficient, ξ is the soil disturbance coefficient, and max() is the maximum value sign. S43: q eff Substituting into the total friction formula, calculate the effective total friction after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal: ; S44: F fk-eff (t) Substitute into the active control coefficient K c The formula for calculating (t) is used to calculate the effective active control coefficient K after considering the friction reduction of thixotropic mud and the effects of soil removal disturbance. c-eff (t): K c-eff (t)=(G k -F fw，k (t)-F add (t) / F fk-eff (t).

[0011] Furthermore, step S4 also includes: Step S45: Determine K c-eff (t) Whether it falls within the target interval [K] c,min ,K c,max ]Inside: If K c-eff (t) <K c,minThis indicates insufficient sinking force of the caisson. Therefore, the outer ring output command is to increase the set rate v of the inner ring. set ←v set +Δv (Δv is taken as 1~2mm / h), and at the same time, a temporary counterweight W(t) is added; the increased v set This causes the inner ring PID to increase soil removal or grouting, reducing F. fk-eff (t), increasing K c-eff (t); If K c-eff (t)>K c,max This indicates that the sinking force of the caisson is too large, so the outer ring output command is to reduce the set speed v of the inner ring. set ←v set -Δv (Δv is taken as 1~2mm / h), and start the reverse lifting T(t); reduce v set To reduce soil removal or stop grouting in the inner ring PID, increase F. fk-eff (t), decrease K c-eff (t); If K c-eff (t) If it is within the target interval, then maintain the current v. set constant.

[0012] Furthermore, it also includes step S5: precipitation settlement calculation and reinjection feedback control.

[0013] Further, step S5 includes: S51: Calculation of Effective Stress Increment: Effective Stress Increment in Soil Caused by Precipitation Calculate using the following formula: ,in γ represents the effective stress increment at a point z in the stratum caused by precipitation. w Let be the specific weight of water, and Δh(z) be the drawdown at depth z caused by precipitation. S52: Layered summation method for settlement calculation: Ground or foundation settlement s is: Where s is the final settlement (m) of the ground surface or building foundation caused by precipitation, and ψ w This is the empirical coefficient for settlement. Let b be the effective stress increment at the midpoint of the i-th soil layer caused by precipitation. i Let E be the thickness of the i-th soil layer. si Let be the compression modulus of the i-th soil layer under lateral confinement conditions, and n represent the total number of soil layers in which the foundation soil within the depth range affected by precipitation is divided.

[0014] S53: Settlement Calculation Using the Layered Sum-of-Step Method Define the cumulative settlement s over time (cumulative settlement) S 累 (t), when the measured settlement rate V 实>0.2mm / d or cumulative settlement s over time (cumulative settlement) S 累 (t) > 0.8S lim (S) lim When the building's allowable cumulative settlement is reached, the recharge system is activated.

[0015] Furthermore, after starting the reinjection system in step S53, the reinjection flow rate Q inj Adjust as follows: Q inj (t) = max(0, Q) inj (t-1)+ɑ(S) 累 (t)-S lim )+β(V 实 (t)-V 允 ), where Q inj (t) represents the current reinjection flow rate (m³). 3 / d); Q inj (t-1) represents the reinjection flow rate (m³) at the previous time step. 3 / d); α and β are empirical coefficients; S lim V represents the allowable cumulative settlement of the building. 允 To allow for the settling rate; reinjection pressure ≤ 0.1 MPa.

[0016] Compared with the prior art, the present invention has at least one of the following technical effects: 1. This invention overcomes the limitations of traditional methods that rely solely on rate feedback. It calculates the effective active control coefficient in real time using an outer-loop supervisor. When K... c-eff (t) When the force is below the lower limit (insufficient sinking force), the rate setting value is automatically increased and the counterweight is added; when the force is above the upper limit (excessive sinking force), the rate setting value is decreased and reverse jacking is initiated. This method prioritizes ensuring that the caisson is under stress within the safe range of "sinkable, non-sudden, and non-jammed," and then finely adjusts the rate through the inner loop PID control. This solves the problems of sudden sinking and well jamming caused by excessive mud sleeve thickness or abrupt changes in sand layer density, significantly improving construction safety and final sinking accuracy.

[0017] 2. Traditional PID rate controllers cannot detect abnormal changes in wellbore friction, and may "blindly" adjust soil extraction, thus exacerbating risks. This invention proposes a quantifiable active control coefficient K. c-eff (t) is calculated, and an explicit mathematical model (exponential decay and linear disturbance superposition) is established between it and the soil extraction depth increment and mud injection volume. By calculating this coefficient in real time and comparing it with the target interval, operators and control systems can intuitively grasp the stress safety margin of the caisson, thereby proactively adjusting control strategies before danger occurs and transforming post-event remediation into pre-event prevention.

[0018] 3. This invention addresses the increase in effective stress and consolidation settlement caused by rainwater seepage. It establishes a quantitative settlement calculation model based on the layered summation method and innovatively employs an incremental PI control law to regulate the recharge flow rate. When the measured settlement rate or cumulative settlement exceeds a threshold, the recharge flow rate is adjusted incrementally in real time according to the deviation, achieving "recharge on demand, replenishment when exceeding the standard." When settlement is safe, recharge is automatically reduced to avoid excessive water level rise. This method upgrades settlement control from traditional empirical threshold start-stop to continuous, closed-loop feedback regulation, effectively suppressing uneven settlement and tilting of buildings, and the protection effect is quantifiable and traceable.

[0019] 4. This invention addresses the deviation of the caisson's tilt angle by independently setting up an incremental PID controller, which outputs a virtual control variable Δu. θ (t), and explicitly map it to the soil sampling depth increment Δd of the high-side or low-side sector. high / Δd low (or asymmetric mud injection flow rate difference). Δd is given. high / Δd low The specific formula also specifies the superposition rules and safety constraints with the rate control output (such as soil removal on one side not exceeding 30% of the suspended height of the cutting edge). This scheme quantifies and programmably performs tilt correction actions, avoiding over-correction or under-correction caused by manual experience, and improves the accuracy of caisson verticality control. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating a method for controlling the settlement of caissons and disturbance of adjacent buildings in a water-rich sand layer according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0023] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0024] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0025] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0026] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0028] See appendix Figure 1 A method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers is disclosed. The method includes the following steps: Step 1: Active control strategy for the sinking process.

[0029] 1.1 Accurate calculation of wellbore friction.

[0030] According to the "Design Specification for Highway Bridge and Culvert Foundations" (JTG 3363-2019), the standard value of unit side friction increases linearly within the depth range of ≤5m, and is a constant below 5m.

[0031] Let the unit frictional resistance at a depth of 5m be q0, then the function f(z) representing the distribution of side frictional resistance along the depth can be expressed piecewise as:

[0032] For a single homogeneous soil layer, the standard value of total skin friction F fk for: Where q0 is the unit frictional resistance (kPa) at a depth ≥ 5m, U is the perimeter of the outer wall of the caisson (m), and H(t) is the depth of penetration (m), where H(t) is greater than 5m. For multi-layered soil, the contribution of each layer is first calculated according to the above formula (note that the initial value corresponding to the starting depth of each layer is non-zero), and the total frictional resistance is the algebraic sum of the layers.

[0033] 1.2. Sinking coefficient and active control coefficient.

[0034] According to Section 4.4 of the national standard "Code for Construction of Caissons and Pneumatic Caissons" (GB / T51130-2016), the sinking coefficient k st The formula for calculating (t) is: k st (t)=(G k -F fw，k (t)) / F fk (t). In the formula G k F represents the standard value of the caisson's self-weight (kN). fw，k (t) represents the buoyancy force of the water (0 when the water is drained and sinks).

[0035] Define the active control coefficient K c (t) represents the ratio of the actual effective sinking force to the real-time frictional force at the current moment: K c (t)=(G k -F fw，k (t)-F add (t) / F fk (t).

[0036] Where F add (t) represents the counterweight or reverse jacking force at the top of the caisson (positive value for jacking, negative value for counterweight). The counterweight refers to the temporary application of additional weight to the top of the caisson (such as stacking steel ingots, concrete blocks, or applying pressure via hydraulic jacks) to increase the effective sinking force and help overcome excessive side friction or end resistance. The reverse jacking force utilizes jacks positioned around or at the bottom of the caisson to apply an upward lifting force to the bottom of the caisson, used to slow the sinking speed or correct tilting, preventing sudden sinking or over-sinking. Both together constitute the active control coefficient K. c F in (t) add (t), where the counterweight is negative (increases the sinking force) and the reverse jacking is positive (reduces the sinking force), and the precise control of the caisson's attitude is achieved through real-time adjustment.

[0037] By adjusting the soil extraction speed and the amount of mud injected, F can be changed. fk (t), maintained within the target interval [K c,min K c,max In this embodiment, K is taken as... c,min =1.05, K c,max =2.0.

[0038] When the soil removal speed inside the well increases, the supporting force at the bottom of the well decreases, and the sinking rate of the caisson increases. This causes an increase in the relative displacement rate between the well wall and the surrounding sand, resulting in dilatation or shear contraction of the sand. This alters the horizontal earth pressure (i.e., lateral pressure) acting on the well wall, thus affecting the decrease in unit frictional resistance q0 and the total frictional resistance F. fk (t) decreases accordingly. Conversely, slowing down the soil extraction speed can restore soil density and increase frictional resistance.

[0039] Adjusting the mud injection rate involves injecting thixotropic mud into the gap between the wellbore and the formation, forming a continuous mud sleeve. This transforms the direct friction between the sand and the wellbore into shear flow resistance of the mud. The static shear stress of thixotropic mud is very low (typically 50-200 Pa), thus reducing the unit frictional resistance q0 from tens to tens of kPa in sand to 3-5 kPa or even lower. Therefore, F fk (t) decreased significantly.

[0040] Adjusting the soil extraction rate and the mud injection volume, both of which are achieved by changing the mechanical properties of the interface between the well wall and the soil (including the coefficient of friction, contact pressure, or lubrication conditions) to dynamically control the total frictional resistance.

[0041] The active control coefficient K c (t) remains within the target range [K c,min ,K c,max The core purpose of K (usually taken as 1.05~2.0) is to ensure that the caisson is always in a state of force equilibrium that allows it to sink but does not sink suddenly: when K c When (t) < 1.05, the effective sinking force is less than the total frictional resistance, and the caisson will stop sinking or even get stuck. It is necessary to increase the counterweight or accelerate soil removal to raise K. c (t); when K c When (t) > 2.0, the effective sinking force far exceeds the frictional resistance, and the caisson may suddenly accelerate its sinking (sudden sinking), leading to tilting, over-deviation, or even structural damage. It is necessary to reduce K by suspending soil removal or reverse jacking. c (t). Therefore, by adjusting the soil extraction speed and mud injection volume in real time, K can be made... c (t) The caisson sinking rate and attitude are kept stable within the range, which can avoid the two extreme working conditions of stuck well and sudden sinking, and achieve precise control of the sinking rate and attitude of the caisson, ensuring construction safety and final sinking accuracy.

[0042] 1.3 Algorithm for controlling the settling rate of caissons based on incremental PID.

[0043] In practice, the control system collects the sinking rate v in real time. 实 (t) and the set value v set (5~10 mm / h), calculated deviation: e v (t) = v set -v 实 (t). The control variable u(t) (slurry injection flow rate or soil sampling depth) is calculated using the incremental PID formula: Δu(t) = K p [e(t)-e(t-1)]+K i e(t)+K d [e(t)-2e(t-1)+e(t-2)]. Where K p =0.8, K i =0.1, K d =0.05.

[0044] The incremental PID controller uses the deviation e of the caisson sinking rate as the reference. v (t) is the input, and the output is the control quantity Δu(t). This control quantity directly determines the adjustment value of the soil sampling depth or the change value of the thixotropic mud injection flow rate. By adjusting the soil sampling depth or mud injection flow rate in real time, the total frictional resistance F of the wellbore can be changed in real time. fk (t), controlling the sinking speed of the caisson to be close to v set This ensures that the caisson's sinking rate and tilt angle quickly and stably approach the set values, guaranteeing a smooth and controllable sinking of the caisson. This allows the active control coefficient K to... c (t) stabilizes within the target range; when the PID control cannot effectively regulate due to insufficient counterweight capacity of the caisson itself or excessive frictional resistance fluctuations, the well counterweight or reverse jacking system is activated as a secondary control means (to increase or decrease the effective sinking force respectively), thereby forming a hierarchical collaborative control of "PID continuous fine-tuning + counterweight / jacking discrete coarse-tuning" to ensure the caisson sinks smoothly and its attitude is controllable under various working conditions.

[0045] Incremental PID formula Δu(t) = K p [e(t)-e(t-1)]+K i e(t)+K d [e(t)-2e(t-1)+e(t-2)] and the active control coefficient K c The technical relationship between (t) is reflected in the closed-loop feedback control chain: the PID deviation e(t) is usually defined as the difference between the set sinking rate and the actual rate (or the difference between the set tilt angle and the actual tilt angle), while the actual rate and tilt angle are directly affected by K. c The magnitude and rate of change of (t) affect (K) cThe larger the value of Δu(t), the stronger the tendency for sinking acceleration. The Δu(t) calculated by PID is converted into an adjustment amount for the soil extraction depth or mud injection flow rate, thereby changing the total frictional resistance F of the wellbore. fk (t), and thus adjust K c The value of (t); the corrected K c (t) Changing the motion state of the caisson generates new measured values ​​of velocity and inclination angle, which are then compared with the set values ​​to obtain a new deviation e(t+1), forming a closed loop. Therefore, the PID formula is the core of the control algorithm, K c (t) is an intermediate mechanical state variable, and the two are connected through "deviation → control quantity → frictional resistance → K". c The causal chain “(t)→motion state→new deviation” achieves dynamic coupling.

[0046] Initial setting value v set The value is determined based on the safety of the caisson structure, soil characteristics, and construction experience, defining a suitable sinking rate range (generally 5~10 mm / h). During construction, the outer ring supervisor determines the value based on K. c (t) Dynamic adjustment.

[0047] 1.4 Monitoring and Adjustment of Caisson Settlement Rate Range When the control quantity Δu(t) output by the inner loop PID is analyzed as the soil sampling depth increment Δd exc (mm) or thixotropic mud injection flow rate increment ΔQ slurry At (L / min), the effective unit frictional resistance q after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal. eff The formula for (kPa) is as follows: Where q0 is the unit frictional resistance value of the caisson sidewall at a depth of 5m (kPa), λ is the mud friction reduction efficiency coefficient (min / L), and ξ is the soil disturbance coefficient (kPa / mm).

[0048] This formula is based on the following assumptions: mud injection causes frictional resistance to decrease exponentially (derived from the permeability theory of mud diffusion), and soil removal disturbance causes frictional resistance to decrease linearly (derived from lateral stress release), and the effects of the two can be linearly superimposed (coupling is not considered). When both effects occur simultaneously, the base value after mud-induced friction reduction is calculated first, and then the additional reduction caused by soil removal disturbance is added. 0.5 kPa is the minimum residual frictional resistance to avoid the exponential term approaching 0 when the mud injection volume is too large. During construction, λ and ξ need to be calibrated through field tests. The unit of λ is min / L, with a value range of 0.1~0.5 min / L, obtained by fitting through field mud injection tests; the unit of ξ is kPa / mm, with a value range of 0.05~0.2 kPa / mm, determined through soil removal disturbance tests. Note Δd. exc It should not exceed 30% of the height of the blade foot in the air, ΔQ slurryIt should not be too large to avoid mud loss.

[0049] The above q eff Substituting into the total friction resistance formula, we obtain the effective total friction resistance F after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal. fk-eff (t), will update F fk-eff (t) Simultaneously substitute the active control coefficient K c The formula for calculating (t) is used to calculate the active control coefficient K after considering the friction reduction of thixotropic mud and the effects of soil removal disturbance. c-eff (t), and determine whether it falls within the target interval [K]. c,min ,K c,max Within [the loop], a closed loop is formed. Determine K. c-eff (t) Whether it falls within the target interval [K] c,min ,K c,max ]Inside: If K c-eff (t) <K c,min This indicates insufficient sinking force of the caisson. Therefore, the outer ring output command is to increase the set rate v of the inner ring. set ←v set +Δv (Δv is taken as 1~2mm / h), and a temporary counterweight W(t) can also be added at the same time; the increased v set This causes the inner ring PID to increase soil removal or grouting, reducing F. fk-eff (t), increasing K c-eff (t); If K c-eff (t)>K c,max This indicates that the sinking force of the caisson is too large, so the outer ring output command is to reduce the set speed v of the inner ring. set ←v set -Δv (Δv is taken as 1~2mm / h), and reverse lifting T(t) can also be started; the reduced v set To reduce soil removal or stop grouting in the inner ring PID, increase F. fk-eff (t), decrease K c-eff (t); If K c-eff (t) If it is within the target interval, then maintain the current v. set constant.

[0050] The inner-loop PID ensures stable speed and tilt angle, while the outer-loop monitor (outer-loop PID) indirectly controls K by adjusting the setpoint. c-eff (t) Constraints are kept within a safe range, and the two work together to avoid sudden sinking and well jamming.

[0051] The outer loop monitor is a real-time calculator for the active control coefficient K. c-eff (t) and compare it with the target interval, dynamically adjusting the inner loop PID setpoint (e.g., v). set ) to ensure Kc-eff (t) The upper-level decision-making module that always stays within the safe range. The inner-loop PID is the bottom-level closed-loop controller in the cascaded control structure that directly uses the sinking rate and tilt angle of the caisson as the controlled variables and stabilizes the rate and attitude by adjusting the soil extraction depth or mud injection volume.

[0052] This invention employs "inner loop PID control of rate / tilt angle + outer loop supervisory control K" c-eff The strategy of "(t) interval" is used because it does not rely solely on the inner loop PID to maintain the preset rate v. set This is because in water-rich sand layers, controlling the rate alone cannot avoid two types of dangerous conditions: when the wellbore friction decreases abnormally (e.g., due to excessively thick mud sleeve), even if the sinking rate stabilizes at v... set The effective sinking force may still far exceed the frictional resistance (K). c-eff (t) if too large, it will suddenly sink once it encounters a disturbance; conversely, when the frictional resistance increases abnormally (such as local compaction of the sand layer), even at a low rate, K c-eff (t) Too small a value can also cause well blockage. Directly targeting the rate setting can cause the controller to "blindly" adjust soil sampling or grouting to maintain the rate, which may lead to K... c-eff (t) deviates from the safe range. An outer ring monitoring K is introduced. c-eff (t) and dynamically adjust v set Essentially, it prioritizes force safety as a constraint: when K c-eff (t) When approaching the danger boundary, actively change the rate target to achieve a stable rate for the caisson while ensuring its structural safety. Although this strategy may cause the sinking rate to temporarily deviate from the original set value (e.g., at K... c-eff (t) decreases v when it is too small set This was done to slow down soil removal and allow frictional resistance to recover, but in return, the caisson remained within a mechanically controllable range of "sinkable, non-protruding, and non-jamming," avoiding the risk of imbalance that could not be perceived by rate feedback alone. Therefore, increasing K... c-eff (t) Monitoring is not intended to replace rate control, but rather to add a mechanical safety barrier on top of rate control. This is especially necessary for formations with high risk of sudden changes in frictional resistance, such as water-rich sand layers.

[0053] 2.5 Algorithm for controlling the settling angle of caissons based on incremental PID.

[0054] In practice, at least four static levels and two biaxial inclinometers are symmetrically arranged along the circumference of the top of the caisson to measure the caisson's tilt angle θ(t) (including the direction and magnitude of tilt) in real time. The control system collects the caisson tilt angle θ in real time. 实 (t), and the set value θ set (0.1°) Comparison, calculate the deviation: e θ (t) = θ set -θ实 (t).

[0055] The incremental PID controller uses the same incremental PID structure as the rate control, but its parameters can be tuned independently. The control law is: Δu θ (t)=K pθ [e θ (t)-e θ [(t-1)]+K iθ e θ (t)+K dθ [e θ (t)-2e θ (t-1)+e θ (t-2)]. Where K pθ K iθ K dθ The proportional, integral, and derivative coefficients for tilt control (typical value: K) pθ =1.0, K iθ =0.2、K dθ =0.1). Δu θ (t) is a dimensionless virtual control increment, and the output is the control increment Δu used to correct the verticality of the caisson. θ (t), this control quantity is usually interpreted at the implementation level as the soil extraction depth increment Δd between different sectors of the caisson plane. exc (mm) (unit: mm) or thixotropic mud injection flow rate increment ΔQ slurry (L / min) Control quantity allocation and execution: Δu θ (t) is converted into actual execution instructions. Based on the caisson's tilt direction, the caisson plane is divided into 8 sectors, corresponding to the "high side" and "low side" sectors. Δu θ The sign of (t) determines whether to increase the depth of soil extraction on the higher side (or increase the mud injection on the lower side) or vice versa. The specific mapping relationship is as follows: If Δu θ If (t)>0, then execute: increase the soil sampling depth in the high-side sector by Δd. high =k θ ·Δu θ (t) (mm), while the soil extraction depth in the lower side sector remains unchanged or decreases. Among them, k θ The proportional conversion factor (unit: mm) represents the change in soil sampling depth corresponding to a unit control increment. Its value is determined based on the caisson diameter, soil conditions, and construction experience (usually 5~20 mm).

[0056] If Δu θ If (t) < 0, then execute: increase the soil sampling depth in the lower sector by Δd. low =-kθ ·Δu θ (t) (mm), the high-side sector remains unchanged. This means that the negative control increment of the PID output is inverted and multiplied by the proportional coefficient k. θ This yields the additional soil sampling depth increment in the lower sector; meanwhile, the soil sampling depth in the higher sector remains unchanged (it remains at Δd). exc ). Δu here θ (t) is determined by the tilt angle deviation e θ (t) The signed virtual control quantity calculated by the incremental PID controller, whose sign represents the direction of tilt correction: a positive value indicates that more soil sampling is needed on the high side, and a negative value indicates that more soil sampling is needed on the low side.

[0057] Alternatively, asymmetric mud injection can be used: reduce mud injection on the side where increased frictional resistance is needed, and increase mud injection on the side where decreased frictional resistance is needed.

[0058] Coordination with speed control: Tilt control and speed control can operate independently in parallel, and their outputs Δu θ (t) and Δu v (t) After superposition, the final sector soil extraction depth increment distribution or mud injection flow distribution is formed. When the tilt deviation is large (|e θ (t)∣>2θ set This can temporarily reduce the weight of rate control and prioritize correcting tilt.

[0059] Safety constraints: The increase in soil extraction depth on either side shall not exceed 30% of the height of the cutting edge above the ground, and the increase in flow rate on one side during asymmetric mud injection shall not exceed 50% of the total grouting capacity. When the tilt angle exceeds the warning value (e.g., 0.5°), the system will automatically issue an alarm and recommend pausing the sinking.

[0060] Using the above method, the incremental PID controller outputs Δu θ (t) can be converted into asymmetric soil extraction or grouting actions in real time, dynamically adjusting the caisson attitude so that the tilt angle is always maintained within the set range.

[0061] Step 2: Calculation of precipitation settlement and feedback control of reinjection.

[0062] 2.1 Calculation of effective stress increment.

[0063] Increase in effective stress in soil caused by precipitation Calculate using the following formula (based on the effective stress principle): ; in, This represents the effective stress increment at a point z in the stratum caused by precipitation. γ w The specific weight of water (generally taken as 10 kN / m³)3 ); Δh(z) is the water level drawdown (m) at depth z caused by precipitation.

[0064] This formula is based on Terzaghi's effective stress principle: when the total stress remains constant, the decrease in pore water pressure equals the increase in effective stress. Rainfall lowers the groundwater level, reducing the pore water pressure in the soil below the water level by γ. w ·Δh(z), while the total stress remains unchanged, so the effective stress increases by the same amount. This increment is the direct mechanical cause of the consolidation compression of the sand layer, leading to formation subsidence.

[0065] 2.2 Settlement calculation using the layered summation method.

[0066] Ground or foundation settlement s is: ; Where s is the final settlement (m) of the ground surface or building foundation caused by precipitation. ψ w The settlement empirical coefficient is 0.2 to 0.4 for dense sand layers, taking into account the differences between field conditions and laboratory tests. The effective stress increment (kPa) caused by precipitation at the midpoint of the i-th soil layer is an engineering approximation method. This method discretizes the continuous strata into soil layers of finite thickness and approximates the average value within the layer with the midpoint value.

[0067] b i The thickness (m) of the i-th soil layer; E si Let E be the compression modulus (kPa) of the i-th soil layer under lateral confinement conditions. E represents the ratio of the increase in vertical stress to the increase in vertical strain under complete lateral confinement (no lateral deformation), i.e., Ei. si = / Δε z Units are MPa or kPa. Compression modulus E s The results were obtained through indoor consolidation tests: soil samples were placed inside a ring sampler to restrict lateral deformation, and vertical pressure was applied in stages. The corresponding changes in void ratio were measured, and a compression curve was plotted to calculate E. s =(1+e0) / a v Where e0 is the initial void ratio, a v =-Δe / E represents the compression factor. s The larger the value, the less compressible the soil is, making it a key parameter for calculating foundation settlement.

[0068] n represents the total number of soil layers in which the foundation soil within the depth range affected by precipitation is divided.

[0069] The overall meaning of this formula is: dividing the strata within the precipitation influence area into several thin layers, and for each thin layer, the effective stress increment... The resulting vertical strain is approximately: =Δε z Vertical strain increment Δε z Defined as the ratio of the amount of vertical compression of a soil layer under external force to the original thickness of the soil layer, Δε is the soil layer's compressibility. z Multiply by layer thickness b i The compression amount of this layer (in meters) is obtained, summed, and then multiplied by the empirical coefficient ψ. w This is the total settlement.

[0070] In the layered summation method, the summation term... The obtained result is the theoretical settlement calculated based on the compression modulus Esi measured by indoor lateral compression tests. However, the indoor test conditions (no lateral deformation, continuous loading, and sufficient drainage) deviate from actual field conditions (potential lateral deformation of the soil, stress path differences, construction disturbances, three-dimensional seepage, etc.). Furthermore, the calculation assumes a uniform distribution of the effective stress increment along the layer thickness and uses a midpoint approximation, which also introduces approximation errors. Therefore, it is necessary to multiply by an empirical coefficient ψ. w The theoretical calculations were corrected to make them closer to the measured settlement.

[0071] Empirical coefficient ψ w The value ψ represents the ratio of measured settlement to theoretically calculated settlement, reflecting the combined differences between field conditions and laboratory test conditions. Its value is primarily based on regional engineering experience and specification recommendations. For dense sand layers, due to the good permeability of sand, the fact that compression is largely completed during construction, and the relatively small lateral deformation, the measured settlement is usually lower than the theoretical value. w Take 0.2~0.4; for soft clay, since there is still secondary consolidation after primary consolidation and significant lateral deformation, ψ w It may be greater than 1.0. The specific value can be determined according to the soil layer type and regional experience in the "Code for Design of Building Foundation" (GB 50007-2011).

[0072] 2.3 Feedback control for reinjection.

[0073] Water level and settlement monitoring points were set up at the building foundation. When the measured settlement rate V... 实 >0.2mm / d or cumulative settlement s over time (cumulative settlement) S 累 (t) > 0.8S lim (S) lim When the building's allowable cumulative settlement is reached, the recharge system is activated. Recharge flow rate Q. inj Adjust as follows: Q inj (t) = max(0, Q)inj (t-1)+ɑ(S) 累 (t)-S lim )+β(V 实 (t)-V 允 )); Among them, Q inj (t) represents the current reinjection flow rate (m³). 3 / d); Q inj (t-1) represents the reinjection flow rate (m³) at the previous time step. 3 / d); α and β are empirical coefficients (each taken as 0.5m). 3 / (d·mm) and 5m 3 / (d·mm / d)); S lim The allowable cumulative settlement of the building (mm); S 累 (t) represents the current measured cumulative settlement (mm); V 允 The allowable settlement rate is 0.2 mm / d. V 实 The measured settlement rate is (mm / d). Reinjection pressure ≤ 0.1 MPa.

[0074] Current feed-in flow Q inj (t) is the flow rate Q at the previous time step. inj Based on (t-1), add two correction terms—ɑ(|S lim -S 累 (t)|) is a proportional term, which increases or decreases the flow rate proportionally to the deviation between the current cumulative settlement and the allowable settlement (i.e., the absolute value of the deviation); β(|V) 允 -V 实 (t)|) represents the rate term, which increases the flow rate proportionally to the deviation between the current settlement rate and the allowable rate (this term is positive if the settlement is too fast). Since each iteration implicitly includes the accumulation of historical deviations in Q... inj In (t-1) (because Q) inj (t-1) itself already includes the integral effect of all previous deviations, therefore this formula achieves settlement control without steady-state error: when the cumulative settlement or settlement rate exceeds the target, the reinjection flow rate continuously increases to raise the water level outside the pit and reduce the effective stress increment, thereby inhibiting settlement development. This continues until the settlement is suppressed and returns to within the limit; conversely, when the settlement is much smaller than the limit, both terms are negative, and the flow rate gradually decreases or even stops. This incremental structure avoids the saturation problem caused by direct integration and is easy to directly interface with the existing reinjection pump frequency control interface.

[0075] According to the reinjection flow rate Q inj The formula is used to determine the reinjection flow rate Q before the cumulative settlement exceeds the allowable value and before the actual settlement velocity exceeds the allowable velocity. inj The rate of return gradually decreases over time. This setting aims to ensure that when both building settlement and rate are within safe limits, it indicates minimal disturbance from current precipitation or sufficient hydraulic barrier effectiveness. In this case, recharge should be proactively reduced or even stopped to avoid unnecessary rise in groundwater levels due to excessive recharge, prevent backflow of recharge water towards the caisson, or cause the building foundation to float, while simultaneously conserving water resources and energy. This is an asymmetric control strategy of "recharge on demand, replenish when exceeding limits," rather than continuous proactive adjustment. In engineering practice, when the settlement rate is slow (<0.2 mm / d), there is sufficient time to respond even when approaching the limit, and intervention can be initiated earlier by setting a lower threshold (e.g., 0.6 times the limit). Similarly, to achieve proactive control, the S value in the formula can be simultaneously... lim Replace with S start =0.6S lim And keep the startup logic unchanged.

[0076] This invention retains the caisson and dewatering well. The premise of the dewatering settlement calculation and recharge feedback control is to set up a virtual water-stop curtain between the caisson and the building. The embedding depth is taken as the critical value that makes the water level at the building stable and the effect of further increasing the depth is not obvious (usually 1.0~1.5m).

[0077] Step 3: Implementation of multi-source monitoring and closed-loop control.

[0078] Sensors configured: Caisson attitude (4 hydrostatic levels, 2 dual-axis inclinometers); water level (3 rows of observation wells along the radial direction); settlement (automated monitoring points at the four corners of the structure and around the caisson). Sampling frequency: attitude 2Hz, water level / settlement 0.1Hz. All data is transmitted in real time to the central industrial control computer, which runs the aforementioned outer-loop monitoring + inner-loop PID program, outputting a control command every 10 minutes.

[0079] This invention is the first to propose the concept of "outer ring K". c The control structure of "supervision + inner loop PID program rate / tilt control" solves the problem of stable rate but unbalanced force in traditional methods. A recharge flow feedback model based on settlement rate and cumulative settlement is established to achieve active suppression of precipitation settlement.

[0080] See attached document Figure 2 The present invention also provides a computer device, including: a memory and a processor and a computer program stored in the memory, wherein when the computer program is executed on the processor, it implements the control method for caisson settlement and disturbance of adjacent buildings in water-rich sand layers as described in any of the above methods.

[0081] The computer device may be a desktop computer, laptop, handheld computer, or cloud server, etc. This computer device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that... Figure 2 The examples of computer devices are merely examples and do not constitute a limitation on computer devices. They may include more or fewer components than shown in the illustration, or combinations of certain components, or different components. For example, they may also include input / output devices, network access devices, etc.

[0082] The processor referred to can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0083] In some embodiments, the memory may be an internal storage unit of the computer device, such as a hard drive or RAM. In other embodiments, the memory may be an external storage device of the computer device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory may include both internal and external storage units of the computer device. The memory is used to store the operating system, applications, bootloader, data, and other programs, such as the program code of the computer program. The memory can also be used to temporarily store data that has been output or will be output.

[0084] This invention also provides a computer-readable storage medium storing a computer program thereon. When the computer program is run by a processor, it implements a method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in any of the above methods.

[0085] In this embodiment, if the integrated control unit is implemented as a software functional unit and sold or used as an independent product for controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers, it can be stored in a computer-readable storage medium specifically designed for controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by instructing the relevant hardware for controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers through a specific computer program. This computer program can be stored in a dedicated computer-readable storage medium for controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers. When executed by a processor, this computer program can implement the application steps of the above-described method embodiments in controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers. The computer program includes computer program code for controlling caisson settlement and disturbance of adjacent buildings in water-rich sand layers. This computer program code can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium may include at least: any entity or device capable of carrying control computer program code for caisson settlement and disturbance of adjacent buildings in water-rich sand layers to the control equipment for caisson settlement and disturbance of adjacent buildings in water-rich sand layers, recording media, machine tool computer memory, read-only memory (ROM), random access memory (RAM), and other media suitable for distributing control software for caisson settlement and disturbance of adjacent buildings in water-rich sand layers, such as dedicated control cards and data storage cards for caisson settlement and disturbance of adjacent buildings in water-rich sand layers.

[0086] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0087] Those skilled in the art will 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, or a combination of computer software and electronic hardware. 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 implementation should not be considered beyond the scope of this application.

[0088] In the embodiments disclosed in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0089] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

Claims

1. A method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers, characterized in that, Includes the following steps: Step S1: Real-time data acquisition; Step S2: Calculate the wellbore friction F fk (t) and active control coefficient K c (t); Step S3: Set the caisson sinking rate v set Calculate the deviation of the caisson sinking rate e v (t), the incremental PID controller uses e v (t) is the input, and the output control quantity u(t) is the adjustment value Δu(t), where the control quantity u(t) is at least one of mud injection flow rate or soil sampling depth; Step S4: Calculate the effective active control coefficient K after considering the friction reduction of thixotropic mud and the effects of soil removal disturbance, based on the adjustment value Δu(t). c-eff (t), and determine whether it falls within the target interval [K]. c,min ,K c,max If it doesn't fall within the range, adjust v. set To K c-eff (t) falls into the target interval.

2. The method for controlling caisson settlement and disturbance of adjacent buildings in a water-rich sand layer as described in claim 1, characterized in that, The data collected in step S1 includes: the perimeter of the outer wall of the caisson U, the depth of the caisson into the soil H(t), and the unit frictional resistance value at a depth of 5m q0.

3. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 2, characterized in that, F fk The formula for calculating (t) is: Where q0 is the unit frictional resistance value of the caisson sidewall at a depth of 5m, U is the perimeter of the caisson outer wall, and H(t) is the burial depth.

4. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 3, characterized in that, Define the active control coefficient K c (t) represents the ratio of the actual effective sinking force to the real-time frictional force at the current moment, and the active control coefficient K. c The formula for calculating K(t) is: c (t)=(G k -F fw，k (t)-F add (t) / F fk (t); Among them, G k F represents the standard value of the caisson's self-weight. add (t) represents the surface counterweight or reverse jacking force, where positive values ​​represent jacking and negative values ​​represent counterweight; F fw，k (t) represents the buoyancy force of the water.

5. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 4, characterized in that, Step S3 includes: S31: The control system collects the sinking rate v in real time. 实 (t), and the set value v set Calculate the deviation: e v (t) = v set -v 实 (t); S32: The control quantity u(t) is calculated using the incremental PID formula: Δu(t) = K p [e(t)-e(t-1)]+K i e(t)+K d [e(t)-2e(t-1)+e(t-2)], where K p K is the proportionality coefficient. i K is the integral coefficient. d is the differential coefficient.

6. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 5, characterized in that, Step S4 includes: S41: The control quantity Δu(t) output by the inner loop PID is analyzed as the soil sampling depth increment Δd. exc (mm) or thixotropic mud injection flow rate increment ΔQ slurry (L / min); S42: Calculate the effective unit frictional resistance q after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal. eff The calculation formula is as follows: Where q0 is the original unit frictional resistance, λ is the mud friction reduction efficiency coefficient, ξ is the soil disturbance coefficient, and max() is the maximum value sign. S43: q eff Substituting into the total friction formula, calculate the effective total friction after considering the friction reduction effect of thixotropic mud and the disturbance caused by soil removal: ; S44: F fk-eff (t) Substitute into the active control coefficient K c The formula for calculating (t) is used to calculate the effective active control coefficient K after considering the friction reduction of thixotropic mud and the effects of soil removal disturbance. c-eff (t): K c-eff (t)=(G k -F fw，k (t)-F add (t) / F fk-eff (t).

7. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 6, characterized in that, Step S4 also includes: Step S45: Determine K c-eff (t) Whether it falls within the target interval [K] c,min ,K c,max ]Inside: If K c-eff (t) <K c,min This indicates insufficient sinking force of the caisson. Therefore, the outer ring output command is to increase the set speed v of the inner ring. set ←v set +Δv; the increase in v set This causes the inner ring PID to increase soil removal or grouting, reducing F. fk-eff (t), increasing K c-eff (t); If K c-eff (t)>K c,max This indicates that the sinking force of the caisson is too large, so the outer ring output command is to reduce the set speed v of the inner ring. set ←v set -Δv; the decrease in v set This reduces soil removal or stops grouting in the inner ring PID, increasing F. fk-eff (t), decrease K c-eff (t); If K c-eff (t) If it is within the target interval, then maintain the current v. set constant.

8. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 1, characterized in that, It also includes step S5: precipitation settlement calculation and reinjection feedback control.

9. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 8, characterized in that, Step S5 includes: S51: Calculation of Effective Stress Increment: Effective Stress Increment in Soil Caused by Precipitation Calculate using the following formula: ,in γ represents the effective stress increment at a point z in the stratum caused by precipitation. w Let be the specific weight of water, and Δh(z) be the drawdown at depth z caused by precipitation. S52: Layered summation method for settlement calculation: Ground or foundation settlement s is: Where s is the final settlement (m) of the ground surface or building foundation caused by precipitation, and ψ w This is the empirical coefficient for settlement. Let b be the effective stress increment at the midpoint of the i-th soil layer caused by precipitation. i Let E be the thickness of the i-th soil layer. si Let be the compression modulus of the i-th soil layer under lateral confinement conditions, and n represent the total number of soil layers into which the foundation soil within the depth range affected by precipitation is divided. S53: Settlement Calculation Using the Layered Sum-of-Step Method Define the cumulative settlement s over time as S 累 (t), when the measured settlement rate V 实 >0.2mm / d or cumulative settlement s over time S 累 (t) > 0.8S lim At that time, start the recharge system, S lim This refers to the allowable cumulative settlement of the building.

10. The method for controlling the settlement of caissons and disturbance of adjacent buildings in water-rich sand layers as described in claim 9, characterized in that, After starting the reinjection system in step S53, the reinjection flow rate Q inj Adjust as follows: Q inj (t) = max(0, Q) inj (t-1)+ɑ(S) 累 (t)-S lim )+β(V 实 (t)-V 允 ), where Q inj (t) represents the current reinjection flow rate (m³). 3 / d); Q inj (t-1) represents the reinjection flow rate (m³) at the previous time step. 3 / d); α and β are empirical coefficients; V 允 To allow for the settling rate; reinjection pressure ≤ 0.1 MPa.

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