Vacuum preloading and grating-shaped cement stirring wall combined foundation reinforcing system and method

Abstract

The invention relates to the field of civil engineering, and discloses a vacuum preloading and grating-shaped cement stirring wall combined foundation reinforcing system and method, and the system comprises a grating-shaped cement stirring wall, a partitioned vacuum preloading system, a multi-dimensional real-time monitoring system and a central control module. The method comprises the following steps: based on monitoring data, a central control module differentially regulates and controls the vacuum degree of each subarea through an intelligent pressure regulating valve so as to minimize the settlement rate difference of each subarea; meanwhile, the module continuously diagnoses the consolidation bottleneck state, and once the consolidation bottleneck state is judged to be true, a bypass pulse valve is instructed to implement positive pressure pulse intervention on a corresponding partition through a composite drainage node, and then powerful vacuumizing is executed. Deep drainage is enhanced by arranging the composite guide drainage nodes, and uniform sedimentation is achieved through zoning dynamic regulation and control; meanwhile, the solidification bottleneck is actively solved through pulse intervention. All links of the system work cooperatively, functions are complementary, and the foundation reinforcement quality and controllability are comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of civil engineering, and more particularly to a foundation reinforcement system and method using a vacuum preloading combined with a grid-shaped cement mixing wall. Background Technology

[0002] In large-scale civil engineering projects such as ports and storage yards, soft soil foundation treatment is a crucial step in ensuring the safety and long-term stability of the engineering structure. This is especially true for land reclamation sites, where the foundation soil is often composed of silt, clay, and sandy silt, characterized by high compressibility, low strength, high water content, and uneven soil composition. If these sites are not effectively treated and directly used as foundations to support heavy equipment or structures, insufficient bearing capacity and excessive settlement can easily lead to deformation, cracking, or even instability of the superstructure, posing a serious threat to the safety of the project.

[0003] To address the aforementioned issues, existing technologies often employ reinforcement techniques such as vacuum preloading combined with cement mixing walls. However, these conventional combined methods still have inherent technical drawbacks in implementation. Existing technologies typically apply a uniform vacuum load to the entire reinforcement area. However, given the natural heterogeneity of soft soil foundations in both horizontal and vertical directions, this loading method cannot adapt to the actual consolidation requirements of different areas, often leading to significant uneven settlement and affecting the overall flatness and stability of the foundation. Furthermore, as consolidation progresses, the drainage channels within the soil gradually become compacted or even blocked, causing a sharp decline in drainage efficiency in the later stages of consolidation. This leads to a bottleneck in the entire reinforcement process, significantly extending the construction period and increasing energy consumption.

[0004] Therefore, this invention proposes a foundation reinforcement system and method using vacuum preloading combined with grid-shaped cement mixing walls to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a foundation reinforcement system and method using vacuum preloading combined with grid-shaped cement mixing walls, which solves the problems of low control precision in the foundation consolidation process, easy siltation of drainage channels, uneven consolidation of deep soil, and difficulty in actively addressing consolidation bottlenecks.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a foundation reinforcement system for vacuum preloading combined with a grid-like cement mixing wall, the system comprising: A grid-shaped cement mixing wall is installed in the foundation to be reinforced. It is formed by multiple cement mixing piles overlapping each other to form a grid-shaped structure. The grid-shaped cement mixing wall has a composite guide node at the intersection of the grid-shaped cement mixing wall. The permeability of the composite guide node is higher than that of the rest of the grid-shaped cement mixing wall. The vacuum pre-compression system is divided into multiple zones, each equipped with an intelligent pressure regulating valve; The multi-dimensional real-time monitoring system includes settlement observation points, vacuum sensors, lateral displacement meters, and wall stress sensors installed within the partition. The central control module is electrically connected to the multi-dimensional real-time monitoring system and the intelligent pressure regulating valve, and has a pre-set wall-soil collaborative deformation control model. The central control module is used to receive real-time monitoring data from settlement observation points, vacuum sensors, lateral displacement gauges, and wall stress sensors collected by the multi-dimensional real-time monitoring system. The real-time monitoring data is input into the wall-soil collaborative deformation control model for analysis and calculation to generate vacuum degree adjustment instructions for each zone, and the vacuum degree adjustment instructions are sent to the intelligent pressure regulating valve to dynamically adjust the vacuum degree of each zone.

[0007] Preferably, the composite guide node is integrally formed with the grid-shaped cement mixing wall in various ways: During the construction of piles at the intersection of grid-shaped cement mixing walls, coarse aggregates of predetermined particle size and proportion are added to the cement slurry to form a cement-soil aggregate composite with an internally interconnected network of gaps. During pile construction at the intersection of the grid-shaped cement mixing wall, the cement content in the cement slurry is reduced to form a low-strength cement-soil body with a permeability coefficient higher than that of the standard grid-shaped cement mixing wall.

[0008] Preferably, the vacuum pre-compression system is further provided with a bypass pulse valve in each zone. The bypass pulse valve is connected in parallel with the vacuum pipeline corresponding to the zone and connected to an independent pressure source. The bypass pulse valve is electrically connected to the central control module and is used to apply a positive pressure pulse to the corresponding zone according to the pulse command sent by the central control module.

[0009] Preferably, the specific conditions under which the central control module executes the positive pressure pulse are: When the central control module determines, based on real-time monitoring data collected from settlement observation points, that the consolidation state of a certain zone has entered a consolidation bottleneck state; The condition for determining the consolidation bottleneck state is that the settlement rate of the zone satisfies the following formula: ; In the formula, S is the settlement measured at the settlement observation point; t is time; This is the preset settling rate threshold.

[0010] Preferably, when generating vacuum degree adjustment commands, the objective of the wall-soil collaborative deformation control model in its analysis and calculation is to minimize the settlement rate difference between any two zones, and the objective function for the settlement rate difference is: ; In the formula, The settlement rate of zone i is calculated by the central control module based on real-time monitoring data from settlement observation points. This refers to the settlement rate of zone j calculated by the central control module based on real-time monitoring data from settlement observation points.

[0011] Preferably, the wall stress sensor in the multidimensional real-time monitoring system is a vibrating wire stress gauge. The wall stress sensor is embedded near the composite guide node. The wall stress sensor is used to monitor the stress response data of the composite guide node in real time when the vacuum preloading system dynamically adjusts the vacuum degree or applies a positive pressure pulse, and sends the stress response data as part of the real-time monitoring data to the central control module.

[0012] This invention also provides a foundation reinforcement method for vacuum preloading combined with a grid-shaped cement mixing wall, the method comprising the following steps: S1. Construct a grid-shaped cement mixing wall that penetrates the soft soil layer, and form a composite drainage node at the intersection of the grid-shaped cement mixing wall with a permeability higher than the remaining part of the grid-shaped cement mixing wall. S2. Install a zoned vacuum pre-compression system and a multi-dimensional real-time monitoring system; S3. The multi-dimensional real-time monitoring system is used to collect real-time monitoring data, and the central control module analyzes and calculates the real-time monitoring data based on the wall-soil collaborative deformation control model to generate vacuum degree control instructions for each zone and perform differentiated dynamic vacuum degree control for each zone. S4. During the differentiated dynamic vacuum degree control process, the central control module continuously determines whether there is a zone that has entered the consolidation bottleneck state. S5. When it is determined that a certain partition has entered the consolidation bottleneck state, the central control module instructs the bypass pulse valve corresponding to the partition to open to apply a positive pressure pulse, and after the bypass pulse valve closes, it instructs the vacuum pump of the partition to pump air at a power higher than the normal operating power.

[0013] Preferably, in step S1, the step of constructing a grid-shaped cement mixing wall that penetrates the soft soil layer includes: During the process of using a deep mixer for shotcreting, at least one reciprocating operation of sinking and re-mixing and lifting and re-mixing is performed to improve the uniformity of the mixing of cement slurry and foundation soil.

[0014] Preferably, when the central control module performs differentiated dynamic vacuum degree control on each zone based on the wall-soil collaborative deformation control model, the control objective on which the vacuum degree control command is generated is to minimize the settlement rate difference between any two zones.

[0015] Preferably, in step S4, during the differentiated dynamic vacuum control process, the step of the central control module continuously determining whether there is a zone entering the consolidation bottleneck state includes: The central control module performs comprehensive analysis on the settlement data, vacuum data, lateral displacement data and wall stress data collected by the multi-dimensional real-time monitoring system to determine whether there are any zones that have entered the consolidation bottleneck state.

[0016] This invention provides a foundation reinforcement system and method for vacuum preloading combined with grid-shaped cement mixing wall, which has the following beneficial effects: 1. This invention integrates a composite drainage node at the intersection of the grid-like cement mixing wall in the load-bearing structure, forming a large-diameter and structurally stable vertical drainage main channel that penetrates the soft soil layer. This composite drainage node, in conjunction with traditional plastic drainage boards, constitutes a three-dimensional drainage network combining points, lines, and surfaces. This effectively avoids drainage failures caused by twisting, breaking, or clogging when relying solely on plastic drainage boards, ensuring long-term unobstructed and efficient drainage throughout the entire reinforcement period.

[0017] 2. This invention divides the reinforced area into multiple independent zones and utilizes a central control module, a multi-dimensional real-time monitoring system, and a wall-soil collaborative deformation control model. Based on real-time settlement and stress response data for each zone, it can independently, dynamically, and in a closed-loop feedback manner adjust the vacuum level of each zone. This differentiated control method replaces the one-size-fits-all loading mode of traditional vacuum preloading, enabling precise control over soil differences and consolidation responses in different areas. This results in more uniform foundation settlement and effective control of lateral displacement.

[0018] 3. To address the consolidation bottlenecks such as settlement stagnation that easily occur in the later stages of traditional vacuum preloading, this invention proposes a cyclical treatment method involving positive pressure pulses and powerful vacuum pumping. The positive pressure pulses applied through the advantageous channel of the composite drainage node actively disturb the local soil structure, breaking existing soil arching effects or clearing blocked drainage channels; the subsequent powerful vacuum pumping rapidly removes the disturbed, easily flowing pore water. This proactive intervention capability improves the reinforcement effect and success rate of the technical solution for deep, complex soft soil foundations.

[0019] 4. This invention organically integrates a grid-like cement mixing wall (for load-bearing and constraint), a composite drainage node (vertical main drainage channel), and a zoned dynamic vacuum preloading system (intelligent control method) into a cohesive whole. The grid wall provides a stable boundary and zoned foundation for vacuum preloading, the composite drainage node improves the efficiency of drainage and pressure pulses, and the intelligent control system maximizes the functions of the former two. This system-level integrated design allows each technical component to support each other and complement each other's functions, thereby comprehensively improving the final quality and controllability of foundation reinforcement. Attached Figure Description

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

[0021] Figure 1 This is a partial three-dimensional structural schematic diagram of the foundation reinforcement system according to an embodiment of the present invention; Figure 2 This is a partial cross-sectional schematic diagram of the foundation reinforcement system according to an embodiment of the present invention; Figure 3 This is an embodiment of the present invention. Figure 2 Enlarged view of point A in the middle; Figure 4 This is a partial top view of the foundation reinforcement system layout according to an embodiment of the present invention; Figure 5 This is a block diagram showing the connection relationship between the central control module and various system components in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the relationship between the settling rate and vacuum degree control in a certain zone according to an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating a certain partition of the present invention entering a consolidation bottleneck state and undergoing pulse intervention. Figure 8 This is a process flow diagram of dynamic compaction pretreatment according to an embodiment of the present invention; Figure 9 This is a flowchart illustrating the construction process of the cement mixing wall according to an embodiment of the present invention.

[0022] Description of Figure Numbers: 1. Grilled cement mixing wall; 11. Composite guide joint; 2. Zoning vacuum pre-compression system; 21. Drainage board; 22. Main vacuum pipe; 23. Vacuum branch pipe; 24. Sealing membrane; 25. Sealing canopy; 26. Intelligent pressure regulating valve; 27. Bypass pulse valve; 3. Settlement observation points; 4. Vacuum sensor; 5. Lateral displacement meter; 6. Site drainage board; 7. Wall stress sensor; 100. Central control module; 200. Multi-dimensional real-time monitoring system. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] It should be noted that, in the absence of conflict, the following embodiments and features can be combined with each other; and, based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0025] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0026] like Figures 1 to 5 As shown, this embodiment of the invention provides a foundation reinforcement system using a vacuum preloading combined with a grid-like cement mixing wall. The system includes: a grid-like cement mixing wall 1, a zoned vacuum preloading system 2, a multi-dimensional real-time monitoring system 200, and a central control module 100. The multi-dimensional real-time monitoring system 200 is electrically connected to the central control module 100, and the central control module 100 is electrically connected to the zoned vacuum preloading system 2.

[0027] like Figure 1 and Figure 2 As shown, the grid-shaped cement mixing wall 1 is arranged in a grid pattern in the soft soil foundation to be reinforced. Its wall structure is composed of multiple cement mixing piles, used to provide bearing capacity to the foundation soil, restrain its lateral deformation, and serve as a seepage prevention boundary for vacuum preloading. Figure 4As shown, at the intersection of the grid-like cement mixing wall 1, a composite drainage node 11 is integrally formed. The structure of this composite drainage node 11 makes its permeability coefficient higher than that of the standard grid-like cement mixing wall 1, thus forming a vertical main drainage channel penetrating the soft soil layer. The composite drainage node 11 is formed by: adding coarse aggregate of a predetermined particle size and proportion to the cement slurry during the pile construction at the intersection of the cement mixing wall; or reducing the cement content during the pile construction at the intersection.

[0028] like Figures 2 to 4 As shown, a zoned vacuum preloading system 2 covers the reinforced area surrounded by a grid-like cement mixing wall 1. The system includes a drainage board 21, a main vacuum pipe 22, vacuum branch pipes 23, a sealing membrane 24, and a sealing canopy 25. The drainage board 21 is vertically installed within the soil surrounded by the grid-like cement mixing wall 1. The vacuum branch pipes 23 communicate with the top of the drainage board 21, and the main vacuum pipe 22 collects multiple vacuum branch pipes 23. The sealing membrane 24 covers the foundation surface, with its edges sealingly connected to the top of the grid-like cement mixing wall 1. The sealing canopy 25 covers the sealing membrane 24 and the grid-like cement mixing wall 1. The system is divided into multiple independent control zones according to geological conditions or design requirements. Each control zone's vacuum pipeline is equipped with an intelligent pressure regulating valve 26 and a bypass pulse valve 27.

[0029] like Figure 5 As shown, the intelligent pressure regulating valve 26 is installed on the vacuum line connecting to the corresponding zone, and is used to receive control signals from the central control module 100 and adjust the vacuum level of the zone according to the control signals. The bypass pulse valve 27 is connected to the main vacuum line and to an external pressure source, and is used to receive pulse commands from the central control module 100 and apply positive pressure to its zone instantaneously.

[0030] like Figure 5 As shown, the multi-dimensional real-time monitoring system 200 is used to collect state data during the foundation reinforcement process. The system includes multiple sensors deployed within the reinforcement area, including at least: settlement observation points 3, vacuum sensors 4, lateral displacement gauges 5, and wall stress sensors 7. Settlement observation points 3 are used to monitor the vertical settlement of each section of the foundation; vacuum sensors 4 are used to monitor the real-time vacuum level of each section; lateral displacement gauges 5 are used to monitor the lateral displacement of the grid-like cement mixing wall 1; and wall stress sensors 7 are embedded within the grid-like cement mixing wall 1 and adjacent to the composite guide node 11, used to monitor stress changes in the wall structure under vacuum load and pulse pressure. Figure 3 As shown, the foundation reinforcement system of the vacuum preloading combined grid-shaped cement mixing wall may also include a site drainage board 6 for draining surface water.

[0031] The hardware of the central control module 100 can be a programmable logic controller (PLC) or an industrial control computer. The central control module 100 has a pre-set wall-soil co-deformation control model and establishes communication connections with the multi-dimensional real-time monitoring system 200 and the valves of the zoned vacuum preloading system 2. The central control module 100 receives real-time monitoring data from the multi-dimensional real-time monitoring system 200, performs calculations using the wall-soil co-deformation control model, and generates control commands which are sent to the intelligent pressure regulating valve 26 and bypass pulse valve 27 of each zone.

[0032] During operation, the wall-soil collaborative deformation control model of the central control module 100 continuously receives settlement data from each zone and dynamically and independently adjusts the opening of the intelligent pressure regulating valve 26 of each zone with the goal of minimizing the difference in settlement rate between each zone, thereby achieving differentiated closed-loop control of the vacuum degree of each zone.

[0033] Meanwhile, the central control module 100 performs real-time diagnosis of the consolidation bottleneck status of each zone based on the received settlement data.

[0034] When the central control module 100 determines that any zone has entered a consolidation bottleneck state, it will immediately send an opening command to the bypass pulse valve 27 corresponding to that zone, applying one or more brief positive pressure pulses to the deep foundation through the composite guide node 11. After the pressure pulse ends, the central control module 100 instructs the vacuum pump of that zone to operate at maximum power to perform a powerful vacuuming operation.

[0035] like Figures 1 to 3 As shown, the grid-shaped cement mixing wall 1 is arranged in a grid pattern in the soft soil foundation to be reinforced. This grid-shaped cement mixing wall 1 is composed of multiple overlapping cement mixing piles. Its function is to bear the upper load, restrain the lateral deformation of the foundation soil during vacuum preloading, and act as a physical seepage barrier to maintain the airtightness of the vacuum preloading system. In this embodiment, the grid-shaped cement mixing wall 1 is constructed using a land-based quadri-axis deep mixing machine. The diameter of the single-axis mixing piles constituting the wall is 900mm, and the overlap width between adjacent piles is 200mm, thus forming a continuous wall structure. The cement slurry used to make the mixing piles is composed of P.O42.5 ordinary Portland cement, with a water-to-cement ratio of 0.9, and the cement content in the cement-soil mixture is not less than 20%.

[0036] like Figures 1 to 4As shown, at the intersection of the longitudinal and transverse walls of the grid-like cement mixing wall 1, a composite drainage node 11 is integrally formed. The permeability coefficient of this composite drainage node 11 is significantly higher than that of the standard wall portion of the grid-like cement mixing wall 1. Therefore, it forms a large-diameter, structurally integrated, vertical drainage main channel penetrating the depth of the soil layer in the soft soil layer. The specific formation methods of this composite drainage node 11 include the following two.

[0037] The first method involves adding coarse aggregate with specific physical properties to the cement slurry to be injected at the intersection area of ​​the grid-like cement mixing wall 1. Specifically, 5% to 15% of the solid mass of standard P.O42.5 cement slurry is mixed with pea gravel or sunflower seed flakes with a particle size ranging from 5mm to 10mm. After forced mixing by a deep mixer, the mixed slurry forms a porous cement-soil aggregate composite with the in-situ soil. Upon solidification, this cement-soil aggregate composite forms a composite drainage node 11, whose internal interconnected network of gaps due to the presence of aggregate results in a permeability coefficient far exceeding that of a standard wall composed entirely of cement and soil.

[0038] The second method involves adjusting the cement slurry mix ratio at the intersection of the grid-like cement mixing wall 1, specifically by reducing the cement content. While maintaining a water-cement ratio of 0.9, the cement content is reduced from no less than 20% in the standard wall to a range of 8% to 12%. The composite drainage node 11 formed using this low-content cement slurry exhibits lower solidification strength than the standard wall, but a more developed internal pore structure and a permeability coefficient one to two orders of magnitude higher.

[0039] The composite drainage node 11 has a dual function in the entire foundation reinforcement system. First, as a highly permeable vertical drainage main channel, during the vacuum preloading stage, its top is fluidly connected to the negative pressure zone of the vacuum pipe network through the ground surface. Together with the grid-distributed drainage boards 21, it forms a three-dimensional drainage network combining points and lines, greatly shortening the discharge path of deep pore water in the foundation and accelerating the consolidation process of the soil. Second, as a structured low-resistance channel, during the active pulse intervention stage, its top is also fluidly connected to the pressurization zone of the vacuum pipe network on the ground surface. When the bypass pulse valve 27 injects high-pressure gas into the vacuum pipe network, the composite drainage node 11 constitutes the main physical path for the pressure pulse to be transmitted to the deep foundation, enabling the high-pressure gas to be transmitted to the deep foundation without loss, thereby overcoming problems such as soil arching or drainage channel blockage that may occur in the later stages of consolidation.

[0040] like Figures 2 to 5As shown, the zoned vacuum preloading system 2 is installed within the foundation reinforcement area defined by the grid-shaped cement mixing wall 1. The system includes a vertically arranged drainage board 21, vacuum branch pipes 23 communicating with the top of the drainage board 21, a main vacuum pipe 22 collecting the vacuum branch pipes 23, a sealing membrane 24 covering the ground surface and airtightly connected to the grid-shaped cement mixing wall 1, and a vacuum pump unit providing negative pressure to the entire pipe network system. Furthermore, the system can be equipped with a sealing canopy 25, which covers the sealing membrane 24 and the grid-shaped cement mixing wall 1, providing physical protection for the system and further enhancing its airtightness.

[0041] The entire vacuum preloading system in this embodiment of the invention is zoned. Specifically, based on the soil layer unevenness data obtained from the foundation survey, or according to the design requirements of the superstructure load distribution, the area enclosed by the grid-like cement mixing wall 1 is divided into multiple independent control zones. Each control zone's vacuum pipeline network (including the main vacuum pipe 22 and vacuum branch pipes 23) constitutes a relatively independent subsystem. This subsystem is connected to the main vacuum pump group or the zone vacuum pump through its dedicated control valve group, thereby achieving independent application and control of the vacuum level in each zone.

[0042] like Figure 4 and Figure 5 As shown, to achieve precise control of the vacuum level in each zone, an intelligent pressure regulating valve 26 is installed on the main vacuum pipe 22 of each control zone. This intelligent pressure regulating valve 26 is an electric or pneumatic proportional regulating valve. Its valve body receives continuous control signals from the central control module 100, such as a standard 4-20mA industrial current signal or a digital signal based on a communication protocol. The valve opening is proportional to the received signal value. By adjusting the valve opening, the air extraction rate of the zone's pipeline can be precisely controlled, thereby achieving continuous and dynamic adjustment of the vacuum level within the zone's foundation.

[0043] To enable proactive intervention in specific zones, a bypass pulse valve 27 is installed on the pipeline of each controlled zone. This bypass pulse valve 27 is a normally closed, fast-switching solenoid valve. It is installed by connecting it in parallel with the main vacuum pipe 22 of the zone via a bypass pipeline, the other end of which is connected to an independent pressure source, such as an air compressor or high-pressure gas tank. The bypass pulse valve 27 receives discrete pulse commands from the central control module 100. Upon receiving the discrete pulse command, the valve opens instantaneously, injecting high-pressure gas from the pressure source into the vacuum network of the zone within a preset short time, thereby applying a positive pressure pulse to the deep foundation through the composite guide node 11. After the command ends, the valve immediately closes, restoring the vacuum seal of the zone.

[0044] like Figure 1 , Figure 4 and Figure 5 As shown, the foundation reinforcement system of this embodiment includes a multi-dimensional real-time monitoring system 200. This system is used to collect various physical state parameters of the foundation throughout the reinforcement process and transmit the collected data to the central control module 100 in real time, providing data input for subsequent closed-loop control and active intervention. The multi-dimensional real-time monitoring system 200 consists of various sensors deployed inside and outside the reinforcement area, as well as data transmission components.

[0045] like Figure 4 As shown, the multi-dimensional real-time monitoring system 200 includes the following sensors: settlement observation points 3, vacuum sensors 4, and lateral displacement gauges 5. Settlement observation points 3 consist of reinforced concrete observation piles embedded in the foundation surface, arranged in a grid density of one pile every 10 meters within each control zone. The elevation of the top of the observation piles is periodically measured using a total station or level to obtain the vertical settlement data of the foundation in each zone. Vacuum sensors 4 are embedded at the vacuum pipeline nodes and under the sealing membrane 24 within each control zone to obtain the real-time vacuum value at their location. Lateral displacement gauges 5 are installed on the outside of the grid-like cement mixing wall 1 to obtain the horizontal displacement data of the wall under vacuum load.

[0046] like Figure 1 and Figure 5 As shown, the multi-dimensional real-time monitoring system 200 also includes a wall stress sensor 7. This wall stress sensor 7 is a vibrating wire stress gauge, embedded within the wall structure of the grid-like cement mixing wall 1, adjacent to the composite guide node 11. Its function is to acquire stress response data of this critical structural location, the composite guide node 11, under changes in vacuum and the positive pressure pulse applied by the bypass pulse valve 27. This data provides a basis for the central control module 100 to analyze the wall structure status and optimize the control model.

[0047] Regarding data acquisition and transmission, all the aforementioned sensors (data from settlement observation point 3 is collected by measuring instruments and then manually input or automatically transmitted) are connected to one or more data acquisition units via electrical signals. Each data acquisition unit converts the physical signals (e.g., voltage, current, frequency) output by each sensor into digital signals and packages them according to a preset communication protocol. Subsequently, the data acquisition unit transmits the digital information containing real-time data from each sensor to the central control module 100 via a wired (e.g., RS485 industrial bus) or wireless (e.g., 4G or 5G cellular network) communication link.

[0048] like Figure 5As shown, the foundation reinforcement system of this embodiment includes a central control module 100. The physical entity of the central control module 100 can be a programmable logic controller (PLC) control cabinet or an industrial control computer. The module contains a software program that implements a wall-soil co-deformation control model, used to receive data from the multi-dimensional real-time monitoring system 200 and generate control commands for the zoned vacuum preloading system 2.

[0049] The working logic of the wall-soil co-deformation control model is implemented by the following modular functions: The model includes a differentiated control logic module. During system operation, the central control module 100 continuously receives real-time settlement data from each settlement observation point 3 in the multi-dimensional real-time monitoring system 200, and uses this as input to initiate differentiated control. The function of this module is to generate differentiated control commands for each zoned vacuum preloading system 2 based on the real-time monitoring data, in order to achieve uniform settlement of the foundation. When generating vacuum control commands, the objective of the module's analysis and calculation is to minimize the settlement rate difference between any two control zones. The objective function for this settlement rate difference is: ; In the formula, The settlement rate of zone i is calculated by the central control module 100 based on the real-time monitoring data of settlement observation point 3; The central control module 100 calculates the settlement rate of zone j based on real-time monitoring data from settlement observation point 3. This module continuously receives real-time settlement data from various settlement observation points 3 in the multi-dimensional real-time monitoring system 200, performs calculations using the aforementioned objective function, generates a set of independent control signals for different zones, and sends them to the corresponding intelligent pressure regulating valves 26 for each zone. By adjusting the valve opening, the vacuum extraction efficiency of each zone is changed, thereby dynamically and differentially adjusting the vacuum level within the foundation of each zone.

[0050] The model also includes a consolidation bottleneck diagnosis logic module. This module determines whether each control zone has entered a consolidation bottleneck state, resulting in reduced drainage efficiency, based on real-time settlement data. Specifically, this module continuously tracks the settlement rate of each zone over time. When the settlement rate of a zone is continuously below a preset rate threshold for a given period (e.g., 24 hours), a judgment condition is triggered. This judgment condition is expressed by the following formula: ; In the formula: S represents the cumulative settlement of a specific control zone, the data of which comes from settlement observation point 3 within that zone, and the unit is millimeters (mm). t represents time, and the unit is days (d). The real-time settlement rate of this specific control zone is calculated by the central control module 100 by performing time derivative on the continuous settlement data S, with the unit being millimeters per day (mm / d). The threshold value for judging the consolidation bottleneck state is preset. This value is set in advance based on the soil engineering properties and the final degree of consolidation required by the design, for example, 1 mm / d.

[0051] The model further includes a pulse intervention decision logic module. When the consolidation bottleneck diagnosis logic module determines that a specific partition meets the above requirements... Upon meeting the conditions, the pulse intervention decision logic module is immediately activated. This module will instantly generate one or a series of preset parameters for active pulse intervention commands, which are sent to the bypass pulse valve 27 connected in parallel on the partition pipeline, driving the valve to open within a set time period (e.g., 0.5 to 2 seconds) to perform an active intervention.

[0052] To further illustrate the present invention, the foundation reinforcement method provided by the present invention will be described below with reference to a specific embodiment.

[0053] Reference Figures 1 to 9 The vacuum preloading combined with grid-shaped cement mixing wall foundation reinforcement method of this invention is applied in one embodiment to the secondary foundation reinforcement project of the bucket wheel excavator foundation area in a port operation area. This site was formed by hydraulic filling, with a soft soil layer thickness of 5 to 11 meters. The foundation soil mainly consists of silt, silty clay, and silty sand, characterized by high compressibility and low strength. The purpose of this method is to meet the requirements of heavy-load operation of the bucket wheel excavator for foundation bearing capacity and settlement control.

[0054] Step S1 (Site preparation and construction of grid-shaped cement mixing wall): See Figure 8 In this embodiment, step S1 includes the following sub-steps: Step S81 (Site Leveling and Cleaning): This step involves preliminary treatment of the construction site of the bucket wheel excavator foundation area, including removing debris and loose soil up to a depth of about 0.4 meters from the ground surface, and using a bulldozer or grader to perform preliminary site leveling to ensure that the construction area is clean and tidy, providing conditions for subsequent surveying and setting-out work.

[0055] Step S82 (Measurement and layout, marking the first compaction points): This step uses a total station or theodolite for precise measurement and layout. Mark the positions of the first compaction points on the site according to the design requirements. The spacing and arrangement of the points are based on the design drawings. The compaction points are arranged with a 1 / 4 hammer diameter overlap to ensure uniform coverage.

[0056] Step S83 (First Compaction Point Construction): This step uses dynamic compaction equipment (e.g., a 20t crawler crane with a 10t circular hammer) to compact the soil at each of the designated first compaction points. The energy of the first compaction is set to 600KJ, and the dynamic compaction shock wave is formed by the free fall of the hammer to improve the density of the shallow soil of the foundation.

[0057] Step S84 (filling and leveling of rammed pits): In this step, several rammed pits are formed after the first ramming. The pits are filled with materials such as crushed stone and graded sand and gravel. Then, a road roller or vibratory tamper is used to level the surface to eliminate the impact of uneven rammed pits on the accuracy of subsequent ramming construction.

[0058] Step S85 (Measurement and layout, marking the second compaction points): In this step, the measurement and layout are carried out again. According to the design requirements, the positions of the second compaction points are marked on the site. They are usually staggered relative to the first compaction points to achieve full coverage.

[0059] Step S86 (Second Round of Compaction): This step uses the same dynamic compaction equipment to compact the soil at the second round of compaction points, increasing the compaction energy to 1000KJ to further reinforce the foundation soil. The compaction points are still arranged with a 1 / 4 diameter overlap.

[0060] Step S87 (Pit Filling and Leveling): In this step, after the second tamping, pit filling is carried out again, and leveling equipment is used to level the site surface to ensure that the overall elevation meets the design requirements.

[0061] Step S88 (As-built Elevation Measurement): After compaction and leveling, this step involves using a level and other measuring equipment to re-measure the site elevation, confirming the consistency between the foundation flatness and the design elevation, and ensuring that the construction quality meets the standards.

[0062] Step S89 (Final Site Leveling): If there are deviations in the measurement results in this step, a small amount of additional material or leveling is required to finally level the site precisely to the design elevation, providing a stable platform for subsequent cement mixing wall construction.

[0063] Step S90 (Entering the grid-shaped cement mixing wall construction): After completing the foundation reinforcement and site leveling, the construction of the grid-shaped cement mixing wall will proceed to the pile laying and mixing stage, which specifically includes drilling, grouting, in-situ mixing and other processes.

[0064] Figure 9 This is a flowchart illustrating the reciprocating process of sinking and re-mixing, and lifting and re-mixing during the construction of the grid-shaped cement mixing wall in this embodiment of the invention. (See attached document.) Figure 9 The process includes the following steps: In step S91, after the site is subjected to dynamic compaction and leveling, preparation work for the construction of the grid-shaped cement mixing wall 1 is carried out.

[0065] In step S92, a land-based quadri-axis deep mixing machine is used as the construction equipment, and P.O42.5 ordinary Portland cement is used as the main cementing material. Cement slurry is prepared with a water-cement ratio of 0.9 and a cement content of not less than 20% to ensure the strength and uniformity of the cement-soil pile.

[0066] In step S93, the mixer drills along the designed axis to form cement mixing piles with a diameter of 900mm and an overlap width of 200mm between adjacent piles. The piles are then arranged in an interlaced manner to form an overall grid-like cement mixing wall structure.

[0067] Step S94 begins, in which the reciprocating cycle of "sinking and re-mixing, lifting and re-mixing" is executed. The mixing head slowly sinks under its own weight and pressure until it reaches the preset pile bottom design elevation, providing positioning for subsequent shotcreting.

[0068] In step S95, after the mixing head reaches the bottom elevation of the pile, the cement slurry is pumped into the stratum and the mixing head is slowly raised at a speed of no more than 0.5 m / min to achieve the first grouting and mixing, ensuring that the cement slurry is fully mixed with the original soil.

[0069] In step S96, after raising the mixing head to the designed elevation of the pile top, it is lowered down to the pile bottom again to perform a secondary mixing treatment on the formed cement-soil pile. Grout can be added as needed to further enhance the strength and uniformity of the pile bottom.

[0070] In step S97, the mixing head is raised a second time at a set speed to complete the second lifting and re-mixing process, so as to ensure that the cement slurry is fully and evenly distributed throughout the entire length of the mixing pile.

[0071] In step S98, it is determined whether at least one complete reciprocating cycle of "sinking and stirring and lifting and stirring" has been completed. If not, the process returns to step S94 to continue the cycle until the design requirements are met.

[0072] After the reciprocating operation is completed, proceed to step S99. For the area where the composite guide node 11 is set, at the corresponding cross pile position, according to the design requirements, grout mixed with coarse aggregate or cement grout with low cement content can be used for specific part construction to achieve differentiated enhancement and guide function.

[0073] Step S2 (System Installation): During the curing of the grid-shaped cement mixing wall 1, a zoned vacuum preloading system 2 and a multi-dimensional real-time monitoring system 200 are installed. Within each control zone enclosed by the grid-shaped cement mixing wall 1, drainage boards 21 are vertically inserted at intervals of 1.0 to 1.5 meters. A pipe network consisting of a vacuum main pipe 22 and vacuum branch pipes 23 is laid, and intelligent pressure regulating valves 26 and bypass pulse valves 27 are installed. Subsequently, a sealing membrane 24 is covered on the surface, its edges being compacted with the top of the grid-shaped cement mixing wall 1 using sandbags to form an airtight connection.

[0074] Simultaneously, a multi-dimensional real-time monitoring system 200 was deployed. According to the design drawings, settlement observation points 3 were embedded in each zone, vacuum sensors 4 were installed at vacuum pipeline nodes, lateral displacement gauges 5 were installed on the outside of the grid-shaped cement mixing wall 1, and wall stress sensors 7 were embedded inside the wall, adjacent to the composite guide node 11. All sensors were connected to a data acquisition unit via data cables, which communicated with the central control module 100 via a wireless network.

[0075] Step S3 (Differentiated dynamic control of vacuum level): See attached document Figure 6 After the system installation is completed, the vacuum pump unit is started, and the central control module 100 begins to execute closed-loop control based on the wall-soil coordinated deformation control model. The module aims to minimize the difference in settlement rate among different zones and continuously receives and analyzes the settlement data uploaded by each settlement observation point 3.

[0076] For example, if the central control module 100 detects that the settlement rate of zone A (curve VA) is significantly higher than that of the adjacent zone B (curve VB), to prevent excessive uneven settlement, the central control module 100 automatically generates and sends a command to the intelligent pressure regulating valve 26 installed on the pipeline of zone A, slightly reducing its opening, thereby reducing the vacuum level of zone A (curve PA) and slowing down its settlement rate. Simultaneously or subsequently, the module can command the intelligent pressure regulating valve 26 of zone B to slightly increase its opening, increasing the vacuum level of zone B (curve PB) to accelerate its settlement. This process is executed continuously and dynamically until the settlement rates of all zones tend to be consistent.

[0077] Step S4 (Continuous assessment of consolidation bottleneck status): During vacuum preloading, the central control module 100 continuously assesses the consolidation bottleneck state of each control zone. This assessment is a comprehensive analysis process. When the central control module 100 detects the settling rate of a certain zone, it calculates the settling rate according to the formula... When the value is determined to be below a preset threshold (e.g., 1 mm / d), intervention is not performed immediately, but a comprehensive analysis program is initiated.

[0078] The program will retrieve other relevant monitoring data for the zone for cross-validation: checking whether the reading of vacuum sensor 4 in the zone is stably maintained at the target value (e.g., ≥80kPa); checking whether the reading of lateral displacement meter 5 is within the allowable range (e.g., ≤50mm); and checking whether the data of wall stress sensor 7 shows any stress abrupt changes due to abnormal changes in soil pressure. Only after confirming that the vacuum level is normal and the wall condition is stable will the module ultimately determine that the zone has entered a consolidation bottleneck state caused by internal soil factors (e.g., local drainage channel blockage), rather than by system equipment failure.

[0079] Step S5 (Active Pulse Intervention and Powerful Vacuum Pumping): See Figure 7 When the central control module 100 confirms that a certain zone (e.g., zone C in the figure) has entered a consolidation bottleneck state (at time T1), it immediately and automatically executes active pulse intervention. The central control module 100 sends a brief opening command to the bypass pulse valve 27 corresponding to that zone. The valve opens instantaneously, and high-pressure air is injected into the vacuum pipeline network under the ground surface, instantly pressurizing the space under the sealing membrane. This pressure is efficiently transmitted to the deep foundation layer through fluid communication, preferentially selecting the low-resistance channel of the composite guide node 11, thus disturbing the consolidated soil.

[0080] After the pulse ends, the valve closes, and the central control module 100 immediately commands the vacuum pump in that zone to operate at maximum power, performing a powerful vacuuming operation. This operation takes advantage of the opportunity when the soil pore structure is opened up after the pulse disturbance, rapidly extracting the loose pore water, thereby breaking the consolidation bottleneck and restoring the settlement rate (after time T2). This positive pressure pulse and powerful vacuuming operation cycle can be repeated according to preset logic until the consolidation state of that zone returns to normal.

[0081] Step S6 (Acceptance): Once the consolidation degree of the foundation in all zones reaches the design requirements (e.g., ≥85%), vacuum preloading is stopped. After removing the relevant equipment, the reinforced foundation is inspected for effectiveness. Acceptance criteria include: using the ring cutter method to test the foundation compaction degree, requiring a compaction degree of not less than 95% within the 0-0.8m depth range of the main road area and not less than 94% in other areas; using the bearing plate method to test the resilient modulus, requiring a comprehensive resilient modulus of not less than 40MPa for the main road foundation and not less than 35MPa for other areas. Passing the acceptance test proves that the method described in this embodiment of the invention has achieved the expected foundation reinforcement effect and is ready for subsequent bucket wheel excavator foundation structure construction.

[0082] The embodiments described in detail above are merely specific application examples of the present invention, and the systems and methods disclosed in this invention are not limited to port and wharf engineering. They are equally applicable to other engineering scenarios with similar soft soil foundation reinforcement needs. The following are some other application implementations of the present invention: In railway and high-speed railway engineering, this method can be applied to treat deep and soft foundations. For example, when facing a silt layer with an average thickness of 25 meters, the system and method of this invention can be used to reinforce the foundation through the synergistic effect of vacuum preloading and grid-shaped cement mixing walls, so as to meet the engineering construction requirements of controlling post-construction settlement within 30 centimeters.

[0083] In the field of airport and highway engineering, particularly in large-area soft soil foundation treatment projects for coastal airport runways or reclaimed land areas, the systems and methods of this invention can be adopted. By implementing this invention, the bearing capacity of the foundation can be increased from, for example, 50 kPa before reinforcement to over 150 kPa, and uneven settlement can be effectively controlled.

[0084] In foundation treatment engineering in earthquake-prone areas, embodiments of the present invention can be used for liquefaction-resistant reinforcement of sandy soil foundations. In such applications, the lateral restraint effect of the grid-like cement mixing wall combined with the drainage effect of the vacuum preloading system helps to reduce the accumulation of excess pore water pressure in the foundation soil under seismic loads, thereby improving the liquefaction resistance of the foundation.

[0085] This invention is also applicable to the construction of municipal and industrial facilities where strict control over post-construction settlement is required. For example, in the construction of urban rail transit projects or large storage tank foundations, embodiments of this invention can be used to reinforce the foundation. Furthermore, in deep foundation pit projects, this invention can be used to treat the foundation surrounding the pit to reduce the impact of construction on adjacent buildings.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A foundation reinforcement system for vacuum preloading combined with grid-shaped cement mixing wall, characterized in that, The system includes: A grid-shaped cement mixing wall is installed in the foundation to be reinforced. It is formed by multiple cement mixing piles overlapping each other to form a grid-shaped structure. The grid-shaped cement mixing wall has a composite guide node at the intersection of the grid-shaped cement mixing wall. The permeability of the composite guide node is higher than that of the rest of the grid-shaped cement mixing wall. The vacuum pre-compression system is divided into multiple zones, each equipped with an intelligent pressure regulating valve; The multi-dimensional real-time monitoring system includes settlement observation points, vacuum sensors, lateral displacement meters, and wall stress sensors installed within the partition. The central control module is electrically connected to the multi-dimensional real-time monitoring system and the intelligent pressure regulating valve, and has a pre-set wall-soil collaborative deformation control model. The central control module is used to receive real-time monitoring data from the settlement observation point, the vacuum sensor, the lateral displacement meter, and the wall stress sensor. It inputs the real-time monitoring data into the wall-soil collaborative deformation control model for analysis and calculation to generate vacuum degree adjustment instructions for each zone, and sends the vacuum degree adjustment instructions to the intelligent pressure regulating valve to dynamically adjust the vacuum degree of each zone.

2. The foundation reinforcement system of vacuum preloading combined with grid-shaped cement mixing wall according to claim 1, characterized in that, The composite guide node is integrally formed with the grid-shaped cement mixing wall through various methods: During the construction of piles at the intersection of the grid-shaped cement mixing wall, coarse aggregates of a predetermined particle size and proportion are added to the cement slurry to form a cement-soil aggregate composite with an internal interconnected network of gaps. During the construction of piles at the intersection of the grid-shaped cement mixing wall, the amount of cement in the cement slurry is reduced to form cement-soil with a permeability coefficient higher than that of the standard wall portion of the grid-shaped cement mixing wall.

3. The foundation reinforcement system of vacuum preloading combined with grid-shaped cement mixing wall according to claim 1, characterized in that, The vacuum pre-compression system is also equipped with a bypass pulse valve in each zone. The bypass pulse valve is installed on a bypass pipe connected in parallel with the vacuum main pipe corresponding to the zone. The bypass pipe is connected to an independent pressure source. The bypass pulse valve is electrically connected to the central control module and is used to apply a positive pressure pulse to the corresponding zone according to the pulse command sent by the central control module.

4. The foundation reinforcement system of vacuum preloading combined with grid-shaped cement mixing wall according to claim 3, characterized in that, The specific conditions under which the central control module executes the positive pressure pulse are: When the central control module determines, based on the real-time monitoring data collected by the settlement observation points, that the consolidation state of any zone has entered a consolidation bottleneck state; The condition for determining the consolidation bottleneck state is that the settlement rate of the zone satisfies the following formula: ； In the formula, S is the settlement measured at the settlement observation point; t is time; This is the preset settling rate threshold.

5. The foundation reinforcement system for vacuum preloading combined with grid-shaped cement mixing wall according to claim 1, characterized in that, When generating vacuum degree adjustment commands, the objective of the wall-soil co-deformation control model in its analysis and calculation is to minimize the settlement rate difference between any two zones. The objective function for the settlement rate difference is: ； In the formula, The settlement rate of zone i is calculated by the central control module based on the real-time monitoring data from the settlement observation points. The settlement rate of zone j is calculated by the central control module based on the real-time monitoring data of the settlement observation points.

6. The foundation reinforcement system of vacuum preloading combined with grid-shaped cement mixing wall according to claim 1, characterized in that, The wall stress sensor in the multidimensional real-time monitoring system is a vibrating wire stress gauge. The wall stress sensor is embedded near the composite guide node. The wall stress sensor is used to monitor the stress response data of the composite guide node in real time when the vacuum preloading system dynamically adjusts the vacuum degree or applies a positive pressure pulse, and sends the stress response data as part of the real-time monitoring data to the central control module.

7. A method for foundation reinforcement using a vacuum preloading combined with a grid-like cement mixing wall, applied to the foundation reinforcement system of the vacuum preloading combined with a grid-like cement mixing wall as described in any one of claims 1-6, characterized in that, The method includes the following steps: S1. Construct a grid-shaped cement mixing wall that penetrates the soft soil layer, and form a composite drainage node at the intersection of the grid-shaped cement mixing wall with a permeability higher than the remaining part of the grid-shaped cement mixing wall. S2. Install a zoned vacuum pre-compression system and a multi-dimensional real-time monitoring system; S3. The multi-dimensional real-time monitoring system is used to collect real-time monitoring data, and the central control module analyzes and calculates the real-time monitoring data based on the wall-soil collaborative deformation control model to generate vacuum degree control instructions for each zone and perform differentiated dynamic vacuum degree control for each zone. S4. During the differentiated dynamic vacuum degree control process, the central control module continuously determines whether there is a zone that has entered the consolidation bottleneck state. S5. When it is determined that any partition has entered the consolidation bottleneck state, the central control module instructs the bypass pulse valve corresponding to the partition to open to apply a positive pressure pulse, and after the bypass pulse valve closes, it instructs the vacuum pump of the partition to pump air at a power higher than the normal operating power.

8. The foundation reinforcement method of vacuum preloading combined with grid-shaped cement mixing wall according to claim 7, characterized in that, In step S1, the steps for constructing the grid-shaped cement mixing wall that penetrates the soft soil layer include: During the process of using a deep mixer for shotcreting, at least one reciprocating operation of sinking and re-mixing and lifting and re-mixing is performed to improve the uniformity of the mixing of cement slurry and foundation soil.

9. The foundation reinforcement method for vacuum preloading combined with grid-shaped cement mixing wall according to claim 7, characterized in that, When the central control module performs differentiated dynamic vacuum degree adjustment on each zone based on the wall-soil collaborative deformation control model, the control objective on which the vacuum degree adjustment command is generated is to minimize the settlement rate difference between any two zones.

10. The foundation reinforcement method for vacuum preloading combined with grid-shaped cement mixing wall according to claim 7, characterized in that, In step S4, during the differentiated dynamic vacuum control process, the step of the central control module continuously determining whether there is a zone entering the consolidation bottleneck state includes: The central control module performs comprehensive analysis on the settlement data, vacuum data, lateral displacement data, and wall stress data collected by the multi-dimensional real-time monitoring system to determine whether there are any zones that have entered the consolidation bottleneck state.

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