Precise rectification method for existing multi-high-rise building in soft soil area

Abstract

The application discloses a precision rectification method for existing multi-high-rise buildings in soft soil areas, which comprises the following steps: constructing anchor static pressure piles on the larger and smaller sides of settlement, reserving part of the pile foundation on the smaller side and not sealing the pile, so that the smaller side does not participate in bearing in the initial stage; controlling the trailing settlement of the larger side by using a pile pressing and sinking device, and passively tilting back the smaller side by using the trailing settlement; digging soil under the smaller side, dynamically adjusting the soil digging according to the real-time monitoring of the internal force response of the pile foundation, and controlling the stress release and load redistribution; real-time monitoring of the settlement, inclination and internal force of the pile foundation, establishing a soil digging parameter and response correlation model, dynamically generating soil digging instructions, taking the control of the overall inclination rate of the structure being less than a preset value as the target and the internal force not exceeding the limit as the constraint, presetting an emergency device connected with the pile foundation, automatically triggering load transfer when the threshold value is exceeded, and inhibiting sudden sinking and pile body deflection; and sealing the pile and filling the soil digging hole after rectification. The application solves the problems of complex pile-soil interaction, high risk of sudden sinking, and difficult guarantee of control accuracy in the rectification of existing multi-high-rise buildings in soft soil areas.

Description

Technical Field

[0001] This invention belongs to the field of soil removal and forced landing correction technology, specifically relating to a method for accurately correcting the tilt of existing multi-story buildings in soft soil areas. Background Technology

[0002] In soft soil areas, many multi-story and high-rise buildings, due to their early construction, often use natural or shallow foundations, resulting in inherent deficiencies in foundation bearing capacity. With increasing age, coupled with changes in the surrounding environment, groundwater level fluctuations, and uneven load distribution, some buildings experience uneven settlement, leading to structural tilting exceeding code limits and affecting normal functionality and structural safety. For such tilted buildings, excavation and forced settlement correction is a common method. The basic principle is to excavate soil beneath the foundation on the side with less settlement, guiding controlled settlement of that foundation and gradually restoring the building to its normal tilt.

[0003] However, soft soil, characterized by high compressibility, low strength, and high sensitivity, presents a series of technical challenges during soil removal and correction. First, the plastic deformation of soft soil exhibits a significant hysteresis effect; stress changes triggered by soil removal often manifest as visible structural settlement only hours or even days later. This "stress-strain hysteresis" makes it difficult to achieve precise control using traditional manual control methods based on settlement rate, resulting in a severe mismatch between the amount of soil removed and the actual amount of soil returned. Second, soft soil is prone to sudden plastic failure under localized unloading conditions. When the amount of soil removed exceeds a critical value, the soil may experience sudden settlement within a short period, posing a risk of structural overturning. Third, when using anchored static pressure piles for foundation underpinning, the pile driving itself generates a drag settlement effect, which, if not properly controlled, could further exacerbate the building's tilt. More critically, existing correction methods often treat pile foundations as passive load-bearing components, neglecting real-time monitoring and control of the pile foundation's stress state. During the excavation process, as the stress in the soil between the piles is released, the load originally borne by the foundation soil gradually shifts to the piles, resulting in a dynamic redistribution of axial force and bending moment in each pile. If the excavation location is improperly chosen or the excavation rate is too fast, some piles may become overloaded due to excessive load, or experience excessive bending moment due to uneven stress, leading to pile deflection and even cracking. Pile deflection not only affects the bearing capacity of the pile itself but also further exacerbates soil disturbance, creating a vicious cycle. However, current technologies for monitoring pile internal forces mostly rely on post-event detection methods, which cannot respond and adjust in real time during the correction process, making it difficult to effectively control the load redistribution of the piles.

[0004] Furthermore, current corrective measures rely primarily on manual measurement and experience-based judgment, lacking a systematic data-driven decision-making mechanism. Operators determine the location and amount of soil to be removed the following day based on daily settlement observation data and experience. This open-loop control method not only has a delayed response but also struggles to address the time-varying nonlinear characteristics of soft soil areas. Once abnormal settlement rates or excessive pile stress occur, the optimal intervention window is often missed, leaving only reactive emergency measures, resulting in high safety risks. Summary of the Invention

[0005] In view of this, the present invention proposes a precise method for correcting the tilt of existing multi-story buildings in soft soil areas. The present invention effectively solves the technical problems of complex pile-soil interaction, high risk of sudden settlement, and difficulty in ensuring control accuracy during the tilt correction process of existing buildings in soft soil areas.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas, comprising:

[0008] Static pressure anchor piles are constructed on the side of the building with greater settlement and the side with less settlement respectively. On the side with less settlement, some pile foundations are reserved and not sealed temporarily, so that the pile foundations in this area do not participate in the bearing or only partially participate in the bearing in the initial stage of the tilt correction.

[0009] On the side with greater settlement, a pile driving control device is used to actively control the settlement of the pile driving and dragging, while on the side with less settlement, the settlement of the pile driving and dragging is used to make the building passively tilt back.

[0010] Excavation is carried out under the foundation on the side with smaller settlement. The internal force changes of each pile are monitored in real time. The excavation operation is dynamically adjusted according to the real-time internal force response of each pile to control the release of soil stress between piles and the load distribution of piles.

[0011] Real-time monitoring of building settlement rate and tilt angle, combined with pile foundation internal force monitoring data, establishes a correlation model between soil excavation parameters and pile foundation load changes and structural tilt response, with the goal of controlling the overall structural tilt rate to be less than the preset value (0.2%) and the constraint that the pile foundation internal force does not exceed the limit, dynamically generating soil excavation adjustment instructions;

[0012] An emergency device is pre-set to connect with the existing pile foundation. When the settlement rate or the internal force of the pile foundation exceeds the preset threshold, the emergency device is automatically triggered to transfer the upper load to the pile foundation, thereby suppressing sudden settlement and pile body deflection.

[0013] After the tilting target is achieved, the reserved pile foundation is sealed and the excavation holes are filled.

[0014] Preferably, while the pile foundation on the side with smaller settlement is not sealed, a compressible gasket is set between the pile top and the foundation slab of the pile foundation. The compressible gasket is composed of multiple layers of composite material with different compression moduli. The number of composite layers and material combination are selected according to the estimated settlement in the area, so that the gasket is crushed layer by layer and the settlement space is released in stages during the tilt correction process, thereby realizing nonlinear control of the pile foundation gradually participating in the bearing process.

[0015] The pile driving and settlement control device includes a locking beam and jacks. The locking beam is connected to the constructed pile foundation, and the jacks are set between the locking beam and the foundation slab.

[0016] During the pile driving process, a lifting force adapted to the upper load is applied by jacks, so that a dynamic balance gap is formed between the locking beam and the foundation plate, and the settlement of the pile driving is controlled within the preset range.

[0017] Preferably, the excavation operation is dynamically adjusted based on the real-time internal force response of each pile foundation, specifically including:

[0018] Based on the axial force change rate of each pile foundation, identify the soil unloading sensitive area between piles, and prioritize soil removal in areas where the axial force change rate is less than the first preset threshold.

[0019] Identify the deflection trend of the pile body based on the bending moment distribution curve morphology of each pile foundation, when the peak bending moment location coefficient When it migrates towards the middle of the pile and exceeds the preset value, among which This is the distance from the peak bending moment to the top of the pile. Based on the pile length, it was determined that the pile was at risk of deflection. Soil excavation work in the area surrounding the pile was suspended, and compensatory grouting was performed on the tensile side of the pile.

[0020] Compensation grouting for the soil on the tension side of the pile foundation includes:

[0021] The grouting depth is determined based on the location of the peak bending moment of the pile, and the grouting side position is determined based on the direction of the bending moment.

[0022] With the goal of reducing the real-time bending moment value of the pile to a preset safe range, the grouting pressure and grouting volume are dynamically adjusted until the bending moment distribution curve of the pile returns to a normal shape.

[0023] Preferably, a correlation model is established between the soil excavation parameters and the changes in pile foundation load and structural tilting response, specifically including:

[0024] The location and amount of soil removed are used as the input feature vector. The change in axial force of each pile foundation Change in bending moment and structural back tilt As output feature vector Construct a nonlinear mapping model ,in These are model parameters;

[0025] Multiple sets of measured data from different soil removal stages during the tilt correction process were collected as training samples to train the nonlinear mapping model, resulting in an association model that describes the mapping relationship between soil removal parameters, pile load changes, and structural tilt response.

[0026] During the correction process, the newly collected measured data are used to adjust the model parameters of the correlation model. Online updates enable the model to adapt to the time-varying nonlinear relationship between soil excavation, pile foundation response, and structural tilting in soft soil areas.

[0027] Preferably, dynamically generating soil removal adjustment instructions specifically includes:

[0028] An optimized control model is constructed with the objective function of controlling the overall tilt rate of the structure to be less than 0.2% and the constraints of the axial force of each pile foundation being less than the preset axial force threshold and the bending moment of each pile foundation decreasing to the preset safety range.

[0029] Based on a nonlinear mapping model, the evolution trend of pile foundation internal forces and structural attitude response under the action of candidate soil removal schemes are predicted. The soil removal scheme that minimizes the objective function and satisfies the constraints is selected as the soil removal adjustment command for the next period.

[0030] Preferably, the emergency device pre-connected to the constructed pile foundation specifically includes:

[0031] The emergency device includes anchor bolts, reaction beams, and adjustable pad blocks. The reaction beams are connected to the existing anchor static pressure piles via anchor bolts, and the adjustable pad blocks are installed between the reaction beams and the foundation slab.

[0032] Preset thresholds include sedimentation rate thresholds. and the threshold for sudden changes in internal forces in pile foundations , ;

[0033] When the monitored settling rate or the rate of change of axial force of any pile foundation Bending moment change rate At that time, based on the difference between the current settlement rate and the target settlement rate The adjustable pad assembly is driven to adjust its thickness. This allows the reaction beam to gradually tighten against the foundation slab, transferring the upper load to the pile foundation according to a preset ratio, thus actively suppressing the sudden settlement process.

[0034] Preferably, the adjustable pad assembly is composed of multiple wedge-shaped pads stacked together, and the gap between the reaction beam and the foundation plate can be infinitely adjusted by driving the relative displacement of the wedge-shaped pads.

[0035] Preferably, the reserved pile foundation is sealed and the excavation hole is filled, specifically including:

[0036] The reserved pile foundation was sealed using a graded prestressed tensioning process. The actual axial force value of the pile after the tilt correction was measured. Determine the measured tension control stress ,in To adjust the coefficient, The cross-sectional area of ​​the pile is used to ensure that the initial load distribution of each pile foundation after pile sealing matches the theoretical design value;

[0037] The excavation holes were filled using a segmented grouting process, with the grouting pressure for each segment determined based on the porosity distribution of the soil surrounding the holes. and grouting volume This ensures that the strength and deformation modulus of the filling material match those of the original foundation soil.

[0038] The present invention has achieved at least the following beneficial effects:

[0039] 1. This invention effectively solves the technical problems of complex pile-soil interaction, high risk of sudden settlement, and difficulty in ensuring control accuracy during the tilting correction of existing buildings in soft soil areas.

[0040] 2. The present invention controls the settlement of pile driving within a preset range through the dynamic balance control of the pile driving settlement control device, thereby preventing the building from tilting more severely during the pile driving construction process and creating favorable initial conditions for subsequent soil excavation and tilt correction.

[0041] 3. By gradually tightening and proportionally transferring the material, the sudden settlement process was smoothly suppressed, protecting the safety of the structure and pile foundation.

[0042] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0043] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0044] Figure 1 This is a flowchart illustrating the steps of a method for accurately correcting the tilt of existing multi-story buildings in soft soil areas, as described in an embodiment of the present invention.

[0045] Figure 2 This is a schematic diagram of the structure of the base plate in an embodiment of the present invention;

[0046] Figure 3This is a schematic diagram of the pile driving and sinking control device in an embodiment of the present invention. Detailed Implementation

[0047] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0048] To achieve the above objectives, the present invention provides the following technical solution:

[0049] like Figure 1 As shown in the figure, the present invention provides a method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas. The method mainly includes the following steps:

[0050] Step 1: Construct anchor static pressure piles on the side of the building with greater settlement and the side with less settlement respectively. On the side with less settlement, some pile foundations are reserved and not sealed temporarily, so that the pile foundations in this area do not participate in the bearing or only partially participate in the bearing in the initial stage of the tilt correction.

[0051] Step 2: On the side with greater settlement, use a pile driving control device to actively control the settlement of the pile driving and dragging, and on the side with less settlement, use the settlement of the pile driving and dragging to make the building passively tilt back;

[0052] Step 3: Excavate soil under the foundation on the side with smaller settlement, monitor the changes in internal forces of each pile foundation in real time, and dynamically adjust the excavation operation according to the real-time internal force response of each pile foundation to control the release of soil stress between piles and the distribution of pile foundation load.

[0053] Step 4: Monitor the settlement rate and tilt angle of the building in real time. Combine the pile foundation internal force monitoring data to establish a correlation model between the soil excavation parameters and the changes in pile foundation load and the structural tilt response. With the goal of controlling the overall tilt rate of the structure to be less than 0.2% and the constraint that the pile foundation internal force does not exceed the limit, dynamically generate soil excavation adjustment instructions.

[0054] Step 5: Pre-set an emergency device connected to the constructed pile foundation. When the settlement rate or the internal force of the pile foundation exceeds the preset threshold, the emergency device will be automatically triggered to transfer the upper load to the pile foundation, suppressing sudden settlement and pile deflection.

[0055] Step 6: After the tilt correction target is achieved, the reserved pile foundation is sealed and the excavation hole is filled.

[0056] In this embodiment, anchored static pressure piles refer to steel pipe piles or precast piles that use anchors as reaction devices and are driven into the foundation through static pressure to reinforce existing building foundations. The side with greater settlement refers to the side with a larger settlement in the building's tilt direction, and the side with less settlement refers to the side with a smaller settlement in the building's tilt direction. The provisional unsealing of the reserved pile foundation means that after construction, the pile tops are not immediately cast into a single unit with the foundation slab. This allows the reserved pile foundation to not bear the upper load or only a small load in the initial stage of correction, with the foundation load still mainly borne by the original foundation soil. This creates conditions for the transfer of pile-soil load during subsequent excavation and forced settlement.

[0057] In this embodiment, the pile driving settlement control device refers to a specialized device used to control the drag settlement generated during the construction of anchor static pressure piles. Drag settlement refers to the phenomenon that, during pile driving, the surrounding soil is disturbed due to pile penetration, resulting in additional settlement of the constructed pile foundation or the original foundation. Passive tilting refers to using the drag settlement generated during pile driving to cause the building to naturally sink on the side with less settlement, thereby achieving tilting in the opposite direction of tilting.

[0058] In this embodiment, soil removal refers to locally weakening the foundation soil by drilling and removing soil below the foundation slab on the side with less settlement, thereby guiding the foundation to undergo controllable settlement. Pile foundation internal force monitoring refers to the real-time acquisition of mechanical parameters such as axial force and bending moment of the pile foundation during the correction process using sensors embedded in the pile. Stress release between piles refers to the process where soil removal causes unloading of the soil between piles, resulting in a reduction in soil stress. Pile foundation load redistribution refers to the process where, as stress is released between piles, the load originally borne by the foundation soil gradually shifts to the piles, causing a change in the load distribution among the piles.

[0059] In this embodiment, the settlement rate refers to the amount of settlement of the building foundation per unit time, usually expressed in mm / d. The tilt angle refers to the degree of overall tilt of the building, usually expressed as the tilt rate ‰. The correlation model is a mathematical model describing the mapping relationship between excavation parameters (such as excavation location and volume) and pile foundation responses (axial force changes, bending moment changes) and structural responses (tilt return). Controlling the overall structural tilt rate to be less than a preset value means aiming to bring the building tilt angle back to within the allowable range (within 0.2%) specified in the code. Ensuring that the internal forces of the pile foundation do not exceed limits means that the axial force and bending moment of each pile foundation do not exceed its design bearing capacity and allowable bending moment.

[0060] In this embodiment, the emergency device refers to a load transfer device pre-installed around the excavation area and connected to the constructed pile foundation. It is used to quickly transfer the upper load to the pile foundation when the settlement rate is too fast or the internal forces of the pile foundation change abnormally, preventing sudden structural settlement and pile deflection failure. The preset thresholds refer to settlement rate limits and pile foundation internal force change limits pre-set based on engineering experience and control requirements. The emergency device is triggered when the monitoring data exceeds these limits.

[0061] In this embodiment, pile sealing refers to the final anchoring of the reserved piles that are not yet sealed, so that they form an integral load-bearing structure with the foundation slab. Hole filling refers to grouting and backfilling the boreholes formed during excavation to restore the integrity and bearing capacity of the foundation.

[0062] The beneficial effects of the above technical solution are as follows: By configuring the load-bearing state of the pile foundation in different zones, it creates conditions for load transfer between the pile and soil during forced settlement; through bidirectional control of settlement dragged during pile driving, it achieves synergy between pile foundation construction and the goal of correcting tilt; through dynamic adjustment of soil excavation based on the internal force response of the pile foundation, it achieves precise control of stress release between piles and load redistribution of the pile foundation; through coordinated control of the pile-soil-structure, it achieves optimized control with the goal of controlling the overall structural tilt rate to less than 0.2% and the constraint of not exceeding the limit of the internal force of the pile foundation; it actively suppresses the risk of sudden settlement through emergency devices; and through the construction of a permanent bearing system after tilt correction, it ensures the long-term stability of the tilt correction effect. This method effectively solves the technical problems of complex pile-soil interaction, high risk of sudden settlement, and difficulty in guaranteeing control precision during the tilt correction process of existing buildings in soft soil areas.

[0063] In a preferred embodiment, refer to Figures 2-3 While the pile foundations on the side with smaller settlement are reserved and not sealed, a compressible gasket is set between the pile top and the foundation slab of the pile foundation. The compressible gasket is composed of multiple layers of composite material with different compression moduli. The number of composite layers and material combination are selected according to the estimated settlement in the area, so that the gasket is crushed layer by layer and the settlement space is released in stages during the tilt correction process, thereby realizing nonlinear control of the pile foundation gradually participating in the bearing process.

[0064] The pile driving and settlement control device includes a locking beam and jacks. The locking beam is connected to the constructed pile foundation, and the jacks are set between the locking beam and the foundation slab.

[0065] During the pile driving process, a lifting force adapted to the upper load is applied by jacks, so that a dynamic balance gap is formed between the locking beam and the foundation plate, and the settlement of the pile driving is controlled within the preset range.

[0066] In this embodiment, the compressible gasket refers to a deformable cushion material placed between the pile top and the foundation slab, used to gradually compress and deform during the correction process, releasing settlement space. Multiple layers of composite material with different compression moduli refer to a gasket made of layers of materials with different hardnesses (such as rubber, foam plastic, cork, etc.). Each layer reaches its yield point sequentially under pressure, producing a layer-by-layer crushing effect. Layer-by-layer crushing means that as the upper load increases or the settlement space requirement increases, the different material layers of the gasket are compressed and destroyed sequentially according to the design order, achieving a staged release of settlement space.

[0067] In this embodiment, the estimated settlement refers to the total settlement that the area needs to generate during the tilt correction process, as determined by the tilt correction design calculations. Selecting the number of stacked layers and material combination based on the estimated settlement means calculating how many layers of gaskets are needed and what compression modulus of material is used for each layer, so that the total compressibility of the gaskets matches the estimated settlement, and the compression sequence of each layer is adapted to the settlement development process.

[0068] In this embodiment, the nonlinear control of the pile foundation gradually participating in the bearing process refers to the nonlinear characteristics of the pile foundation from not participating at all to participating partially and then fully participating in the bearing process through the layer-by-layer crushing of the gaskets, so as to avoid load impact or structural vibration caused by the sudden bearing of the pile foundation.

[0069] In this embodiment, the locking beam is a rigid beam spanning above the pile top and connected to the pile body via anchor bolts, used to transfer loads. Jacks are positioned between the locking beam and the foundation slab to apply jacking force. The jacking force adapted to the upper load means that the force applied by the jacks is balanced with the load currently transferred to this area by the upper structure, maintaining a predetermined gap between the locking beam and the foundation slab. The dynamically balanced gap refers to maintaining the gap between the locking beam and the foundation slab within a preset range during pile driving by adjusting the jacking force in real time, ensuring that the gap is neither too large, leading to uncontrolled foundation settlement, nor too small, causing premature load transfer to the pile foundation.

[0070] The beneficial effects of the above technical solution are as follows: through the graded crushing design of the compressible gasket, the nonlinear control of the gradual participation of the pile foundation in the bearing process is realized, avoiding the load impact caused by the sudden bearing of the pile foundation; through the dynamic balance control of the pile driving settlement control device, the settlement of the pile driving drag is controlled within the preset range, preventing the building tilt from intensifying during the pile driving construction process, and creating favorable initial conditions for subsequent soil excavation and tilt correction.

[0071] In a preferred embodiment, the excavation operation is dynamically adjusted based on the real-time internal force response of each pile foundation, specifically including:

[0072] Based on the axial force change rate ΔP_i / Δt of each pile foundation, the soil unloading sensitive area between piles is identified, and soil removal is preferentially carried out in the area where ΔP_i / Δt is less than the first preset threshold.

[0073] The bending moment distribution curve of each pile foundation is used to identify the bending deformation trend of the pile body. When the bending moment peak position coefficient λ_i=L_peak / L_pile migrates to the middle of the pile body and exceeds the preset value, where L_peak is the distance from the peak bending moment to the top of the pile and L_pile is the pile length, it is determined that the pile has a bending risk. The excavation work in the area around the pile is suspended, and the soil on the tension side of the pile is compensated by grouting.

[0074] Compensation grouting for the soil on the tension side of the pile foundation includes:

[0075] The grouting depth is determined based on the location of the peak bending moment of the pile, and the grouting side position is determined based on the direction of the bending moment.

[0076] The goal is to reduce the real-time bending moment value M_i(t) of the pile to the safe range M_i(t)≤β·M_allow,i, where β is the safety factor. The grouting pressure and grouting volume are dynamically adjusted until the bending moment distribution curve of the pile returns to the normal shape.

[0077] In this embodiment, the axial force change rate ΔP_i / Δt refers to the change in axial force of the pile foundation per unit time, reflecting the sensitivity of the soil around the pile to unloading. The larger ΔP_i / Δt is, the more sensitive the soil in that area is to excavation disturbance, and the faster the unloading response. The first preset threshold is a limit value for the axial force change rate set based on engineering experience, used to determine which areas are suitable for priority excavation. Prioritizing excavation in areas where ΔP_i / Δt is less than the first preset threshold means carrying out excavation operations first in areas with relatively gentle unloading response to reduce the risk of sudden settlement.

[0078] In this embodiment, the bending moment distribution curve refers to the curve connecting the bending moment values ​​along each section of the pile, reflecting the distribution characteristics of bending on the pile. The bending moment peak position coefficient λ_i = L_peak / L_pile is the ratio of the distance from the peak bending moment point to the pile top to the pile length, used to quantify the relative position of the peak bending moment on the pile. Under normal circumstances, the peak bending moment should be close to the pile top or pile end; when λ_i approaches 0.5, it indicates that the peak bending moment has migrated towards the middle of the pile, and the pile exhibits a stress state similar to a simply supported beam, increasing the risk of deflection deformation.

[0079] In this embodiment, flexural risk refers to the risk that the pile may undergo excessive bending deformation under excessive bending moment, potentially leading to cracking or failure of the pile. The preset value is a limit value of λ_i determined based on the material properties and stress characteristics of the pile. When λ_i exceeds this limit, a flexural risk is identified. Suspending excavation work around the pile means immediately stopping any excavation operations that may further exacerbate the bending moment of the pile, preventing the risk from worsening.

[0080] In this embodiment, the tension-side soil refers to the surrounding soil corresponding to the tension side of the pile. Compensating grouting on this side can enhance the lateral constraint of the soil on the pile and inhibit further deflection of the pile. Determining the grouting depth based on the peak bending moment location means setting the grouting point at the pile depth corresponding to the peak bending moment, so that the grouting effect directly acts on the part with the most significant deflection. Determining the grouting side location based on the bending moment direction means determining which side of the pile is under tension based on the sign of the bending moment and setting the grouting point in the soil corresponding to the tension side.

[0081] In this embodiment, the real-time bending moment value M_i(t) refers to the pile bending moment monitored at the current moment. The safe range M_i(t) ≤ β·M_allow,i means controlling the bending moment within a certain proportion β of the allowable bending moment M_allow,i, where β is a safety factor less than 1, typically taken as 0.6-0.8. Dynamically adjusting the grouting pressure and grouting volume means continuously adjusting the grouting parameters based on the real-time effect of the bending moment reduction until the bending moment decreases to the safe range and the bending moment distribution curve returns to its normal shape.

[0082] The beneficial effects of the above technical solution are as follows: by identifying the unloading sensitive area through the axial force change rate, the avoidance priority of soil excavation operation is realized, and the risk of sudden settlement is reduced; by identifying the pile body deflection risk through the peak bending moment position coefficient, the early warning and active intervention of the risk are realized; and by targeted compensation grouting based on bending moment response, the deflection of the pile body is accurately suppressed, effectively protecting the safety of the pile foundation structure.

[0083] In a preferred embodiment, a correlation model is established between the soil excavation parameters and the changes in pile foundation load and structural tilting response, specifically including:

[0084] Using the location and amount of soil excavation as the input feature vector X=[x_1,x_2,…,x_n], and the axial force change ΔP_i, bending moment change ΔM_i, and structural tilt Δθ of each pile foundation as the output feature vector Y=[ΔP_1,…,ΔP_m,ΔM_1,…,ΔM_m,Δθ], a nonlinear mapping model Y=F(X,W) is constructed, where W is the model parameter;

[0085] Multiple sets of measured data from different soil removal stages during the tilt correction process were collected as training samples to train the nonlinear mapping model, resulting in an association model that describes the mapping relationship between soil removal parameters, pile load changes, and structural tilt response.

[0086] During the tilt correction process, the model parameters W of the associated model are updated online using newly collected measured data, enabling the model to adapt to the time-varying nonlinear relationship of "soil excavation-pile foundation response-structural tilting" in soft soil areas.

[0087] In this embodiment, the input feature vector X=[x_1,x_2,…,x_n] quantifies the soil removal parameters into a mathematical vector form, where each element x_i represents a feature parameter of a soil removal operation, such as the coordinates of the soil removal location, the soil removal depth, the diameter of the soil removal hole, and the amount of soil removed in a single operation. n is the dimension of the input features, which is determined based on the richness of the actual monitoring data.

[0088] In this embodiment, the output feature vector Y=[ΔP_1,…,ΔP_m,ΔM_1,…,ΔM_m,Δθ] quantifies the system response into a mathematical vector, where ΔP_i is the axial force change of the i-th pile, ΔM_i is the bending moment change of the i-th pile, m is the total number of monitored piles, and Δθ is the overall structural tilt. The dimension of the output feature is 2m+1.

[0089] In this embodiment, the nonlinear mapping model Y=F(X,W) refers to the complex nonlinear functional relationship from input X to output Y, where W is the parameter set of the model. The model can be implemented using machine learning algorithms such as neural networks, support vector machines, and Gaussian process regression. Nonlinearity refers to the complex and nonlinear mapping relationship between the soil excavation parameters and the pile foundation response and structural response, which is difficult to describe with simple linear equations.

[0090] In this embodiment, multiple sets of measured data refer to input-output data pairs (X_k, Y_k) recorded at different stages and under different soil removal operations during the tilting process, where k=1,2,…,K. Training refers to using these data pairs to adjust the model parameters W through an optimization algorithm, minimizing the error between the model's predicted output F(X_k,W) and the measured output Y_k.

[0091] In this embodiment, online updating refers to adding each new set of measured data (X_new, Y_new) to the training sample set and incrementally updating the model parameters W whenever a new set of measured data (X_new, Y_new) is generated during the tilt correction construction process. The time-varying nonlinear relationship refers to the fact that the mapping relationship between "soil excavation-pile foundation response-structural tilting" continuously changes with the construction progress due to factors such as the nonlinear rheological properties of soft soil and the progressive failure of the pile-soil interface. Adaptive capability means that the model can continuously track this time-varying characteristic through online updates, maintaining the accuracy of its predictions.

[0092] The beneficial effects of the above technical solution are as follows: by constructing a nonlinear mapping model, a mathematical description of the complex pile-soil interaction relationship is realized; through training with measured data, the model can accurately reflect the mapping relationship of "soil excavation-pile foundation response-structural tilting" under specific engineering conditions; and through an online update mechanism, the model can adapt to the characteristics of engineering parameters changing over time in soft soil areas, providing a reliable predictive basis for subsequent optimization control.

[0093] In a preferred embodiment, dynamically generating soil removal adjustment instructions specifically includes:

[0094] An optimized control model is constructed with the objective function maxθ<0.002, where the overall tilt rate of the control structure is less than a preset value, and the constraints are P_i≤P_u,i and M_i≤M_allow,i of each pile foundation.

[0095] Based on the nonlinear mapping model Y=F(X,W), predict candidate soil removal schemes X. The evolution trend of internal forces in the pile foundation and the structural attitude response under action are analyzed. The soil removal scheme X_opt that minimizes the objective function and satisfies the constraints is selected as the soil removal adjustment instruction for the next period.

[0096] In this embodiment, the objective function maxθ<0.002 means that the overall tilt rate of the structure is less than two per thousand, aiming to bring the structure back to a horizontal state as much as possible. P_u,i is the design bearing capacity of the i-th pile, and M_allow,i is the allowable bending moment of the i-th pile. The constraints P_i≤P_u,i and M_i≤M_allow_i ensure that the internal forces of all piles remain within a safe range throughout the entire tilt correction process, preventing overload failure.

[0097] In this embodiment, the optimization control model refers to a mathematical programming problem that seeks to minimize the decision variable X, which represents the objective function, while satisfying the constraints. The decision variable X is the soil removal scheme to be determined, including parameters such as the soil removal location and the amount of soil removed.

[0098] In this embodiment, candidate soil removal scheme X refers to multiple possible soil removal schemes generated according to certain rules in the current decision space. Based on the nonlinear mapping model Y=F(X,W), the evolution of axial force, bending moment, and structural tilt angle of each pile foundation under the action of each candidate scheme X can be predicted over a future period. Selecting the soil removal scheme X_opt that minimizes the objective function and satisfies the constraints means selecting the scheme that minimizes the structural tilt angle and ensures that the internal forces of all pile foundations do not exceed the limits from all candidate schemes, and using it as the soil removal command for the next time period to be actually executed.

[0099] In this embodiment, the next time period refers to a time interval set according to the control accuracy requirements, such as generating a new soil removal adjustment command every 4 hours, every 8 hours, or every 24 hours. Through continuous rolling optimization, refined dynamic control of the entire tilt correction process is achieved.

[0100] The beneficial effects of the above technical solution are as follows: by modeling the tilt correction control problem as a constrained optimization problem, scientific decision-making with the goal of restoring the structural attitude and the bottom line of pile foundation safety is realized; through predictive optimization based on nonlinear mapping models, the decision to remove soil is predictable, avoiding the risks brought about by blind trial and error; through rolling optimization strategies, continuous adaptive control of time-varying systems is realized, ensuring the safety and accuracy of the tilt correction process.

[0101] In a preferred embodiment, a pre-installed emergency device connected to the already constructed pile foundation specifically includes:

[0102] The emergency device includes anchor bolts, reaction beams, and adjustable pad blocks. The reaction beams are connected to the existing anchor static pressure piles via anchor bolts, and the adjustable pad blocks are installed between the reaction beams and the foundation slab.

[0103] The preset thresholds include the settlement rate threshold v_th and the pile foundation internal force mutation thresholds ΔP_th and ΔM_th;

[0104] When the monitored settlement rate v(t) > v_th, or the axial force change rate ΔP_i / Δt of any pile foundation > ΔP_th, or the bending moment change rate ΔM_i / Δt > ΔM_th, the adjustable pad block group is driven to adjust its thickness δ = f(Δv) according to the difference between the current settlement rate and the target settlement rate Δv = v(t) - v_target. This causes the reaction beam to gradually tighten with the foundation slab, transferring the upper load to the pile foundation according to a preset ratio, thereby actively suppressing the sudden settlement process.

[0105] In this embodiment, the reaction beam refers to a rigid beam spanning multiple piles and connected to the pile body via anchor bolts, used to evenly transfer the upper load to each pile. The adjustable pad assembly refers to a combination of adjustable-thickness pads placed between the reaction beam and the foundation slab, used to control the contact state between the reaction beam and the slab. The anchor bolt refers to a prestressed tendon that passes through the foundation slab and is anchored to the top of the pile, used to connect the reaction beam and the piles into a whole.

[0106] In this embodiment, the settlement rate threshold v_th refers to the upper limit of the settlement rate set according to the tilt control requirements, typically 5-10 mm / d. The pile foundation internal force mutation thresholds ΔP_th and ΔM_th refer to the upper limits of axial force and bending moment changes per unit time set according to the pile foundation material properties and stress characteristics, used to identify abnormal internal force mutations. When the monitoring data exceeds these thresholds, it indicates that the system may be at risk of instability, requiring emergency intervention.

[0107] In this embodiment, the difference between the current settlement rate and the target settlement rate, Δv = v(t) - v_target, reflects the severity of the current settlement deviation from the ideal state. The target settlement rate, v_target, is the ideal settlement rate set according to the correction plan, typically 2-5 mm / d. Driving the adjustable pad assembly to adjust its thickness, δ = f(Δv), means that based on the magnitude and direction of Δv, the pad assembly is automatically adjusted in thickness by a motor-driven mechanism. The larger Δv is, the greater the thickness adjustment of the pad assembly, allowing the reaction beam to tighten more quickly against the base plate.

[0108] In this embodiment, "gradual tightening" means that the pad block assembly is not completely tightened all at once, but rather the tightening degree is gradually increased proportionally according to the magnitude of Δv, making the load transfer process smooth and controllable. "Transferring the load according to a preset proportion" means that by precisely controlling the thickness of the pad block assembly, a certain proportion (such as 20%, 50%, 80%) of the upper load is gradually transferred to the pile foundation, while the remaining part is still borne by the original foundation, thus achieving a gradual transfer of the load.

[0109] In this embodiment, active suppression means that the emergency device does not only respond passively after sudden subsidence occurs, but also intervenes immediately and proactively when risk signs (excessive settlement rate, sudden change in internal forces) are detected. It controls the development of settlement through load transfer to prevent sudden subsidence.

[0110] The beneficial effects of the above technical solution are as follows: by setting multi-level thresholds and adjustable pad groups, early identification and early intervention of sudden settlement risk are achieved; by dynamically adjusting the thickness based on Δv, precise control of load transfer is achieved, avoiding rigid impact when the emergency device is triggered; by gradually tightening and proportionally transferring, the sudden settlement process is smoothly suppressed, protecting the safety of the structure and pile foundation.

[0111] In a preferred embodiment, the adjustable pad assembly is composed of multiple wedge-shaped pads stacked together. By driving the relative displacement of the wedge-shaped pads, the gap between the reaction beam and the foundation plate can be infinitely adjusted.

[0112] In this embodiment, a wedge-shaped pad refers to a pad with a right-angled trapezoidal cross-section, whose inclined surfaces can fit together. Stacking multiple wedge-shaped pads means placing two or more wedge-shaped pads with their inclined surfaces facing each other. By changing their relative positions, the total thickness of the stack can be adjusted. The thickness is minimal when two wedge-shaped pads completely overlap; the thickness increases when they are offset relative to each other.

[0113] In this embodiment, the relative displacement of the driving wedge-shaped pads refers to the movement of one of the wedge-shaped pads along the inclined plane by a driving device such as a servo motor or lead screw, thereby changing the total thickness of the composite. Stepless adjustment means that the thickness change is continuous and arbitrarily set, rather than a jump-like, step-by-step adjustment, enabling precise control of the gap between the reaction beam and the foundation plate.

[0114] In this embodiment, the wedge-shaped pads are typically made of high-strength steel or engineering plastics to ensure that they do not deform excessively under load. The drive system is equipped with displacement sensors, which can provide real-time feedback on the current thickness of the pad assembly, forming a closed-loop control.

[0115] The beneficial effects of the above technical solution are: by driving the relative displacement of the wedge-shaped pad group, the stepless and precise adjustment of the gap between the emergency device and the foundation plate is realized, providing a hardware foundation for the fine control of the load transfer ratio; compared with the stepless adjustment, the stepless adjustment can adapt to any size of settlement deviation, with higher control accuracy and smoother response.

[0116] In a preferred embodiment, sealing the reserved pile foundation and filling the excavation hole specifically includes:

[0117] The reserved pile foundation is sealed using a graded prestressed tensioning process. Based on the measured axial force value P_i of the pile after the tilt correction is completed, the tension control stress σ_con,i=γ·P_i,measured / A_i is determined by actual measurement, where γ is the adjustment coefficient and A_i is the cross-sectional area of ​​the pile body, so that the initial load distribution of each pile foundation after sealing is consistent with the theoretical design value.

[0118] The excavation holes are filled using a segmented grouting process. The grouting pressure p_j and grouting volume Q_j of each segment are determined based on the porosity distribution of the soil around the excavation holes, so that the strength and deformation modulus of the filling body match the original foundation soil.

[0119] In this embodiment, staged prestressing tensioning refers to a tensioning process in which prestress is applied to the design value in multiple stages, step by step. After each tensioning, the pile foundation and its deformation response are monitored for a period of time. Only after safety is confirmed can the next stage of tensioning be carried out. The measured axial force value P_i refers to the actual axial force value currently borne by the pile, measured by sensors after the tilt correction is completed and before the pile is sealed.

[0120] In this embodiment, the tension control stress σ_con,i = γ·P_i, where measured / A_i is the prestressing target determined based on the measured axial force. γ is an adjustment coefficient, typically taken as 1.0-1.2, used to account for prestress loss and long-term load effects. A_i is the cross-sectional area of ​​the pile. Determining the tension control stress according to this formula ensures that the initial load distribution of the pile foundation after pile sealing matches the actual load distribution when tilt correction is completed, avoiding new uneven settlement caused by improper pile sealing sequence or unreasonable prestressing application.

[0121] In this embodiment, the theoretical design value refers to the load value that each pile foundation should bear, determined through theoretical calculation based on the structural load distribution and pile foundation arrangement after the tilt correction is completed. Ensuring that the initial load distribution after pile sealing matches the theoretical design value means adjusting the prestress to make the actual load borne by each pile foundation as close as possible to the theoretical design value, thus laying the foundation for the long-term stability of the building.

[0122] In this embodiment, segmented grouting refers to dividing the excavation hole into several segments along its depth direction and filling them with grout segment by segment from bottom to top or from top to bottom. Porosity distribution refers to the difference in porosity of soil layers at different depths around the excavation hole, which is usually determined through geological surveys or pre-grouting detection.

[0123] In this embodiment, determining the grouting pressure p_j and grouting volume Q_j for each section based on the porosity distribution means using a larger grouting pressure and volume in sections with higher porosity and a smaller grouting pressure and volume in sections with lower porosity, ensuring that the filling material is tightly bonded to the surrounding soil at different depths. Matching the strength and deformation modulus of the filling material to the original foundation soil means selecting appropriate grouting materials and parameters to ensure that the mechanical properties of the hardened filling material are similar to those of the original foundation soil, avoiding the formation of abrupt stiffness changes below the foundation and preventing new uneven settlement.

[0124] The beneficial effects of the above technical solution are as follows: by using graded prestressing tension based on measured axial force, the load distribution of the pile foundation after pile sealing is accurately matched with the theoretical design value, avoiding new uneven settlement caused by the pile sealing process; by using segmented grouting based on porosity distribution, the stiffness matching between the filling body of the excavation hole and the original foundation soil is achieved, eliminating the hidden danger of sudden stiffness change under the foundation, and ensuring the long-term stability of the building after tilt correction.

[0125] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas, characterized in that, include: Static pressure anchor piles are constructed on the side of the building with greater settlement and the side with less settlement respectively. Some piles on the side with less settlement are left unsealed so that the piles on the side with less settlement do not participate in bearing or only partially participate in bearing in the early stage of tilt correction. On the side with greater settlement, a pile driving control device is used to actively control the settlement of the pile driving and dragging, while on the side with less settlement, the settlement of the pile driving and dragging is used to make the building passively tilt back. Excavation is carried out under the foundation on the side with smaller settlement. The internal force changes of each pile are monitored in real time. The excavation operation is dynamically adjusted according to the real-time internal force response of each pile to control the release of soil stress between piles and the load distribution of piles. Real-time monitoring of building settlement rate and tilt angle, combined with pile foundation internal force monitoring data, establishes a correlation model between soil excavation parameters and pile foundation load changes and structural tilt response, with the goal of controlling the overall structural tilt rate to be less than the preset value and the constraint that the pile foundation internal force does not exceed the limit, and dynamically generates soil excavation adjustment instructions. An emergency device is pre-set to connect with the existing pile foundation. When the settlement rate or the internal force of the pile foundation exceeds the preset threshold, the emergency device is automatically triggered to transfer the upper load to the pile foundation, thereby suppressing sudden settlement and pile body deflection. After the tilting target is achieved, the reserved pile foundation is sealed and the excavation holes are filled.

2. A method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 1, characterized in that, While the pile foundations on the side with smaller settlement are left unsealed, compressible gaskets are installed between the pile tops and the foundation slab of these pile foundations. The compressible gaskets are composed of multiple layers of composite materials with different compression moduli. The number of composite layers and material combination are selected according to the estimated settlement on the side with smaller settlement, so that the gaskets are crushed layer by layer and the settlement space is released in stages during the tilt correction process, thereby achieving nonlinear control of the pile foundation gradually participating in the bearing process. The pile driving and settlement control device includes a locking beam and jacks. The locking beam is connected to the constructed pile foundation, and the jacks are set between the locking beam and the foundation slab. During the pile driving process, a lifting force adapted to the upper load is applied by jacks, so that a dynamic balance gap is formed between the locking beam and the foundation plate, and the settlement of the pile driving is controlled within the preset range.

3. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 1, characterized in that, The excavation operation is dynamically adjusted based on the real-time internal force response of each pile foundation, specifically including: Based on the axial force change rate of each pile foundation, identify the soil unloading sensitive area between piles, and prioritize soil removal in areas where the axial force change rate is less than the first preset threshold. Identify the deflection trend of the pile body based on the bending moment distribution curve morphology of each pile foundation, when the peak bending moment location coefficient When it migrates towards the middle of the pile and exceeds the preset value, among which This is the distance from the peak bending moment to the top of the pile. Based on the pile length, it was determined that the pile foundation was at risk of deflection. Soil excavation work in the area surrounding the pile foundation was suspended, and compensatory grouting was performed on the tensile side of the pile foundation. Compensation grouting for the soil on the tension side of the pile foundation includes: The grouting depth is determined based on the location of the peak bending moment of the pile foundation, and the grouting side position is determined based on the direction of the bending moment. With the goal of reducing the real-time bending moment value of the pile foundation to a preset safe range, the grouting pressure and grouting volume are dynamically adjusted until the bending moment distribution curve of the pile foundation returns to a normal shape.

4. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 1, characterized in that, Establish a correlation model between soil excavation parameters, pile foundation load changes, and structural tilting response, specifically including: The location and amount of soil removed are used as the input feature vector. The change in axial force of each pile foundation Change in bending moment and structural back tilt As output feature vector Construct a nonlinear mapping model ,in These are model parameters; Multiple sets of measured data from different soil removal stages during the tilt correction process were collected as training samples to train the nonlinear mapping model, resulting in an association model that describes the mapping relationship between soil removal parameters, pile load changes, and structural tilt response. During the correction process, the newly collected measured data are used to adjust the model parameters of the correlation model. Online updates enable the model to adapt to the time-varying nonlinear relationship between soil excavation, pile foundation response, and structural tilting in soft soil areas.

5. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 4, characterized in that, Dynamically generate soil removal adjustment commands, specifically including: An optimized control model is constructed with the objective function of controlling the overall tilt rate of the structure to be less than a preset value, and the constraints of the axial force of each pile foundation being less than a preset axial force threshold and the bending moment of each pile foundation decreasing to a preset safe range. Based on a nonlinear mapping model, the evolution trend of pile foundation internal forces and structural attitude response under the action of candidate soil removal schemes are predicted. The soil removal scheme that minimizes the objective function and satisfies the constraints is selected as the soil removal adjustment command for the next period.

6. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 1, characterized in that, The pre-installed emergency device for connection to the existing pile foundation includes: The emergency device includes anchor bolts, reaction beams, and adjustable pad blocks. The reaction beams are connected to the existing anchor static pressure piles via anchor bolts, and the adjustable pad blocks are installed between the reaction beams and the foundation slab. Preset thresholds include sedimentation rate thresholds. and the threshold for sudden changes in internal forces in pile foundations , ; When the monitored settling rate or the rate of change of axial force of any pile foundation Bending moment change rate At that time, based on the difference between the current settlement rate and the target settlement rate The adjustable pad assembly is driven to adjust its thickness. This allows the reaction beam to gradually tighten against the foundation slab, transferring the upper load to the pile foundation according to a preset ratio, thus actively suppressing the sudden settlement process.

7. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 6, characterized in that, The adjustable pad assembly is composed of multiple wedge-shaped pads stacked together. By driving the relative displacement of the wedge-shaped pads, the gap between the reaction beam and the foundation plate can be infinitely adjusted.

8. The method for accurately correcting the tilt of existing multi-story and high-rise buildings in soft soil areas according to claim 1, characterized in that, The reserved pile foundations are sealed and the excavation holes are filled, specifically including: The reserved pile foundation was sealed using a staged prestressed tensioning process. The actual axial force value of the pile foundation after the tilt correction was measured. Determine the measured tension control stress ,in To adjust the coefficient, The cross-sectional area of ​​the pile is used to ensure that the initial load distribution of each pile foundation after pile sealing matches the theoretical design value; The excavation holes were filled using a segmented grouting process, with the grouting pressure for each segment determined based on the porosity distribution of the soil surrounding the holes. and grouting volume This ensures that the strength and deformation modulus of the filling material match those of the original foundation soil.

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