Self-adaptive multidirectional hydraulic foundation pit supporting system for ultra-deep foundation pit and dynamic control method thereof

Abstract

The invention provides a self-adaptive multidirectional hydraulic foundation pit supporting system for an ultra-deep foundation pit and a dynamic control method thereof. The self-adaptive multidirectional hydraulic foundation pit supporting system comprises transverse embedded steel columns, longitudinal embedded steel columns and vertical embedded steel columns, wherein the transverse embedded steel columns and the longitudinal embedded steel columns are embedded in a concrete retaining wall of the foundation pit, and the vertical embedded steel columns are embedded in a raft foundation of the foundation pit. The transverse embedded steel columns, the longitudinal embedded steel columns and the vertical embedded steel columns are connected to the steel structure space nodes through the corresponding standard steel columns correspondingly, and the steel structure space nodes comprise transverse hydraulic cylinders, longitudinal hydraulic cylinders and vertical hydraulic cylinders which are connected with the standard steel columns in all directions correspondingly and are all connected with pressure sensors and stroke sensors. The central control unit calculates compensation force needed in all directions in real time through a fuzzy PID algorithm on the basis of sensor data and drives the corresponding hydraulic cylinders to dynamically adjust the supporting counter force. The three-dimensional self-adaptive adjusting capacity is stepped, the problem of complex deformation adaptation of the ultra-deep foundation pit is thoroughly solved, the overall stress of the foundation pit is balanced, the construction safety of the ultra-deep foundation pit is remarkably improved, and the construction efficiency is improved by 50% or above.

Description

Technical Field

[0001] This invention relates to the field of foundation pit support engineering technology, and in particular to a support system for foundation pit excavation in building and municipal engineering projects, especially suitable for deep foundation pit construction scenarios in soft soil areas or near existing buildings or underground pipelines. Background Technology

[0002] In the construction of high-rise buildings, underground utility tunnels, and subway stations, foundation pit excavation is a crucial preliminary process. The foundation pit support system, as a core component of the support structure, primarily functions to transmit soil and water pressure from the pit's sidewalls, limit pit deformation, ensure structural safety during excavation, and protect surrounding existing buildings, roads, and underground pipelines from settlement and displacement. As urban construction expands into underground spaces, foundation pit excavation depths are gradually increasing (often reaching 15-30m), and the construction environment is becoming increasingly complex (e.g., adjacent to old buildings and dense pipelines), placing higher demands on the adaptability, stability, and construction efficiency of the support system. Currently, the foundation pit support systems widely used in engineering are still mainly traditional fixed structures, primarily including two types: fixed steel supports and concrete force transfer bands. Fixed steel supports often use H-beams, steel pipes, and other profiles, forming a rigid support system through on-site welding or bolting. Concrete force transfer bands, on the other hand, require reinforcing steel bars to be tied inside the foundation pit, formwork to be erected, and then poured on-site, curing to the design strength to form a force transfer structure. However, these traditional support systems have significant drawbacks in practical applications and are difficult to meet the needs of complex foundation pit construction. Specific problems are as follows: The lack of rigidity adjustment capability can easily lead to safety hazards: Traditional support systems are designed with fixed stiffness and cannot adjust the support force or length in real time according to dynamic deformations (such as sidewall displacement and pit bottom heave) during the excavation process. When the stress distribution of the soil around the pit changes or local deformation increases due to construction disturbances, the fixed support cannot adapt to the amount of deformation, which can easily cause cracking of the support structure, loosening of bolts, and even accidents such as uneven settlement of adjacent buildings and damage to underground pipelines. This problem is particularly prominent in soft soil areas. Deformation monitoring and adjustment lags behind, seriously affecting the construction period: Traditional support systems rely on manual periodic monitoring (such as total station measurements and settlement observation point readings), with long monitoring cycles (usually 12-24 hours / time), and manual judgment is required to determine whether the deformation exceeds the limit; if the deformation is found to exceed the allowable range of the specification (such as side wall displacement ≥30mm), the machine needs to be stopped to formulate a reinforcement plan (such as adding temporary supports and tensioning steel cables). The reinforcement process involves welding, pouring and other procedures, and a single treatment usually takes 3-5 days, which not only delays the excavation period of the foundation pit, but also increases the cost of labor and equipment idle due to the shutdown. The installation and dismantling processes are inefficient and resource utilization is poor: fixed steel supports require multi-segment splicing and welding on-site, and the welding quality is greatly affected by the skill level of workers and weather conditions (such as rain and low temperatures), and it is difficult to adjust their position after installation; concrete force transfer strips require formwork, pouring, and curing (usually 7-14 days), resulting in a long construction cycle, and they cannot be reused after pouring. They need to be crushed and dismantled before backfilling the foundation pit, generating a large amount of construction waste, which does not conform to the concept of green construction. In addition, the dismantling and assembly process of traditional supports requires the cooperation of large hoisting equipment, which is complicated and further restricts the overall efficiency of foundation pit construction. In summary, current traditional foundation pit support systems suffer from problems such as poor rigidity adaptability, slow adjustment response, low construction efficiency, and resource waste, which seriously restrict the construction safety, economy, and environmental protection of deep foundation pit projects and cannot meet the actual needs of foundation pit construction in complex urban environments. Therefore, it is urgent to develop a new type of foundation pit support system that can adapt to foundation pit deformation in real time, is easy to adjust, and is highly efficient to solve the above-mentioned technical pain points.

[0003] It should be noted that the above technical information is intended only to enhance the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any way implying that the above technical information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] To address the shortcomings in the aforementioned background technology, this invention proposes an adaptive multi-directional hydraulic foundation pit support system for ultra-deep foundation pits and its dynamic control method. The technical problem to be solved is: how to improve the adaptive capability and construction efficiency of the foundation pit support system.

[0005] The technical solution of this invention is as follows: An adaptive multi-directional hydraulic foundation pit support system for ultra-deep foundation pits includes transverse and longitudinal embedded steel columns pre-embedded in the concrete retaining wall of the foundation pit, and vertical embedded steel columns pre-embedded in the raft foundation of the foundation pit. The transverse, longitudinal, and vertical embedded steel columns are respectively connected to steel structure spatial nodes through corresponding standard steel columns. The steel structure spatial nodes include transverse, longitudinal, and vertical hydraulic cylinders respectively connected to the standard steel columns in each direction. The transverse, longitudinal, and vertical hydraulic cylinders are all connected to pressure sensors and stroke sensors. Based on the sensor data, the central control unit calculates the required compensation force in each direction in real time using a fuzzy PID algorithm, and drives the corresponding hydraulic cylinders to dynamically adjust the support reaction force.

[0006] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the steel structure spatial nodes are located in the vertical plane of the structure in the width direction of the foundation pit, and a number of steel structure spatial nodes are set along the length direction of the foundation pit.

[0007] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the transverse pre-embedded steel columns, the longitudinal pre-embedded steel columns, and the steel structure spatial nodes are at the same height, which is one-third of the foundation pit depth.

[0008] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the steel structure space nodes include adjacent space nodes and middle space nodes.

[0009] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the adjacent space node includes two horizontal hydraulic cylinders, one longitudinal hydraulic cylinder, and one vertical hydraulic cylinder. The two horizontal hydraulic cylinders are respectively connected to the horizontal pre-embedded steel columns on the left and right sides through standard steel columns on the left and right sides. The longitudinal hydraulic cylinder is connected to the longitudinal pre-embedded steel column near the edge through the corresponding standard steel column. The vertical hydraulic cylinder is connected to the vertical pre-embedded steel column at the bottom through the standard steel column below.

[0010] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the central space node includes two horizontal hydraulic cylinders, two longitudinal hydraulic cylinders, and one vertical hydraulic cylinder. The two horizontal hydraulic cylinders are respectively connected to the horizontal pre-embedded steel columns on the left and right sides through standard steel columns on the left and right sides. The two longitudinal hydraulic cylinders are respectively connected to the adjacent edge space nodes through corresponding standard steel columns. The vertical hydraulic cylinder is connected to the vertical pre-embedded steel column at the bottom through the standard steel column below.

[0011] Based on the above technical solutions, as the preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, each pre-embedded steel column is connected to the adjacent standard steel column, the adjacent standard steel columns are connected to each other, and each hydraulic cylinder is connected to the adjacent standard steel column through flange assemblies.

[0012] Based on the above technical solutions, as a preferred technical solution for the ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system, the steel structure space node includes a cubic body, and the hydraulic cylinders of each hydraulic cylinder are respectively connected to the corresponding structural surface of the cubic body through flange assemblies.

[0013] A dynamic control method for an ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system is proposed. The system employs the aforementioned ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system. The central control unit establishes a three-dimensional dynamic model of foundation pit deformation by fusing various data, and calculates the deformation compensation requirements in each direction (lateral, longitudinal, and vertical) in real time.

[0014] Based on the above technical solutions, as the preferred technical solution for the dynamic control method of the adaptive multi-directional hydraulic foundation pit support system for ultra-deep foundation pits, a force-displacement collaborative control algorithm is adopted: the horizontal, longitudinal, and vertical hydraulic cylinders are divided into linkage groups, and the output ratio of each hydraulic cylinder is optimized and allocated through the objective function to ensure that the vector superposition of the three-dimensional compensation forces is consistent with the actual deformation direction of the foundation pit.

[0015] The linkage logic adopts a master-slave control strategy: the direction with the largest deformation is the master control direction, and the other directions are the slave directions. The compensation force of each hydraulic cylinder is dynamically adjusted by preset weight coefficients to avoid stress concentration in other directions due to overcompensation in a single direction.

[0016] Dynamic priority mechanism: When the deformation rate in a certain direction exceeds the threshold, the system automatically increases the response priority of the hydraulic cylinder in that direction, while reducing the compensation amplitude in other directions to achieve dynamic balance.

[0017] Closed-loop feedback mechanism: The displacement and pressure sensor data of each hydraulic cylinder are fed back to the central control unit in real time. The compensation force is iteratively corrected through the fuzzy PID algorithm to form a closed-loop control of "monitoring-calculation-execution-verification" to ensure the coordination and real-time performance of the three-dimensional compensation force.

[0018] This invention, through an integrated design of "three-dimensional hydraulic drive + intelligent dynamic control," deeply integrates the "hardware support system" and "software control algorithm," specifically addressing the core pain points of traditional foundation pit support systems: "poor rigidity adaptation, lag in adjustment, and coarse control." It is particularly suitable for ultra-deep foundation pit (15-30m) construction in complex scenarios such as soft soil, coastal areas, and proximity to sensitive buildings. It achieves breakthrough improvements in adaptability, control precision, safety, construction efficiency, and scalability, as detailed below: 1. A leap forward in three-dimensional adaptive adjustment capabilities, completely solving the problem of adapting to complex deformations in ultra-deep foundation pits. Traditional supports can only provide unidirectional rigid support, which cannot cope with the three-dimensional coupled deformation of ultra-deep foundation pits caused by soil stress redistribution, water level changes, construction disturbances, lateral sidewall displacement, longitudinal pit tension, and vertical pit bottom heave. This invention achieves self-adaptation through three major innovations.

[0019] On the hardware level: The steel structure space node integrates horizontal / longitudinal / vertical hydraulic cylinders, which can actively extend and retract along the three directions of "width-length-depth" of the foundation pit, with an adjustable stroke covering 300-500mm, meeting the deformation compensation requirements within ±150mm of ultra-deep foundation pits.

[0020] At the algorithm level: The central control unit uses real-time data from pressure / stroke sensors (accuracy ±1mm, ±0.5%FS) to dynamically correct the compensation force through a fuzzy PID algorithm (proportional coefficient Kp=2.5, integral coefficient Ki=0.8, derivative coefficient Kd=0.3), avoiding the overshoot and oscillation problems of traditional PID, and the adjustment response time is ≤0.5s.

[0021] At the coordination level: the force-displacement coordinated control algorithm divides the three-way hydraulic cylinder into linkage groups and optimizes the output ratio through objective functions (such as minimizing the weighted sum of deformation and energy consumption) to ensure that the compensation force vector is completely matched with the deformation direction (adaptation accuracy ≥95%). This completely solves the defect of traditional support where "unidirectional adjustment leads to stress concentration in other directions". The maximum deformation of the foundation pit in soft soil areas can be reduced from the traditional 30mm to less than 8mm.

[0022] 2. Dynamic priority control and closed-loop feedback significantly improve the safety of ultra-deep foundation pit construction. Traditional support systems rely on regular manual monitoring (every 12-24 hours), which can easily lead to support cracking and settlement of adjacent buildings if deformation exceeds the threshold and the system fails to respond in time. This invention constructs a safety protection system of "real-time monitoring - dynamic decision-making - closed-loop correction".

[0023] Dynamic priority mechanism: A preset deformation rate threshold (e.g., 0.5 mm / h) is used. When the deformation rate in a certain direction exceeds the limit (e.g., the deformation rate on the lateral edge reaches 0.8 mm / h), the system automatically sets that direction as the "main control direction" and increases the priority of its hydraulic cylinder response (the adjustment speed increases from 5 mm / s to 8 mm / s). At the same time, the compensation amplitude in other directions is reduced (e.g., the longitudinal compensation force is reduced by 20%) to avoid the spread of local instability.

[0024] Master-slave collaborative control: In response to the stress difference between the edge and the middle of the foundation pit, the lateral deformation of the edge side is the main control direction (weight coefficient 0.6), and the longitudinal and vertical directions are the slave directions (weight coefficients 0.3 and 0.1, respectively). The compensation force is dynamically distributed, and the settlement of adjacent buildings can be controlled within 5mm (15-20mm for traditional supports).

[0025] Closed-loop feedback verification: The pressure / stroke sensor collects data once every 100ms and feeds it back to the central control unit for iterative correction by the fuzzy PID algorithm. The compensation force error is ≤3%, which completely eliminates the risk of lag in manual judgment and reduces the safety accident rate of ultra-deep foundation pits by more than 90%.

[0026] 3. Modular splicing + dynamic adjustment and coordination improve the construction efficiency of ultra-deep foundation pits by more than 50%. Traditional support replacement requires 3-5 days of downtime (manual disassembly and welding), and the adjustment process involves repeated trial and error. This invention improves efficiency through a dual-drive approach of "hardware modularization + software pre-control".

[0027] Modular hardware: Pre-embedded steel columns, standard steel columns, and hydraulic cylinders are all connected by flange components with bolts (no on-site welding required). The installation / removal time for a single support is reduced from the traditional 3 days to 2-4 hours. When replacing the support, only the standard steel column of the appropriate length needs to be replaced. There is no need to dismantle the entire support system, realizing simultaneous operation of "excavation-replacement-adjustment".

[0028] Dynamic pre-control algorithm: The central control unit predicts the deformation demand of the next construction stage (such as an increase of 2m in excavation depth) based on the three-dimensional dynamic model of the foundation pit deformation, and pre-adjusts the stroke of the hydraulic cylinder (error ≤ 5mm) to avoid the passive mode of "remediation after deformation occurs" in the traditional way.

[0029] Improved construction period: The construction period for ultra-deep foundation pits (25m) has been shortened from the traditional 120 days to 60-70 days, and the construction period for the dismantling and replacement of supports has been shortened by 60%, which is especially suitable for key projects such as subways and utility tunnels where "the construction period is tight and work cannot be stopped".

[0030] 4. Differentiated node layout + precise force control optimizes the stress balance of ultra-deep foundation pits. The stress difference between the "edge area" (close to existing buildings / pipelines) and the "central area" of ultra-deep foundation pits is significant (the edge area needs to resist lateral displacement, while the central area needs to balance the force transmission). Traditional supports using a uniform structure are prone to local stress concentration (such as cracking of the edge support and overloading of the central support). This invention achieves this through two major design optimizations.

[0031] Differentiated configuration of nodes: The edge space nodes are equipped with "double transverse + single longitudinal + single vertical" hydraulic cylinders to enhance the transverse anti-lateral displacement capability (the double cylinders work together to offset the edge soil pressure, increasing the bearing capacity by 80%); the middle space nodes are equipped with "double transverse + double longitudinal + single vertical" hydraulic cylinders, which achieve balanced force transmission in the length direction through the bidirectional longitudinal cylinder, avoiding stress concentration in the middle.

[0032] Precise force control algorithm: The fuzzy PID algorithm can dynamically limit the output of hydraulic cylinders according to the design bearing capacity of different areas of the foundation pit (such as 800kN allowable pressure on the edge side and 1000kN allowable pressure on the middle side), avoiding local overload (pressure overshoot ≤5%). The overall stress non-uniformity coefficient of the ultra-deep foundation pit support system is reduced from the traditional 0.3 to below 0.15.

[0033] 5. It boasts strong intelligent compatibility and scalability, adapting to various scenarios and ultra-deep foundation pit construction. This invention not only meets the requirements of conventional ultra-deep foundation pits, but also has the ability to adapt to multiple scenarios and expand functionality: Scene compatibility: Through hardware optimization (such as using 316L stainless steel for hydraulic cylinders to cope with seawater erosion in coastal areas, and adding water-stop rings to flange components to prevent seepage), it can be adapted to complex geological conditions such as soft soil, coastal areas, and high water levels; by adjusting control algorithm parameters (such as increasing the integral coefficient Ki in soft soil areas to 1.0), it can match the deformation characteristics of different soil types.

[0034] Functional expandability: The central control unit has a reserved data interface, which can be connected to the foundation pit water level monitoring instrument, the settlement sensor of surrounding buildings, and the weather station (wind speed / rainfall) to realize multi-parameter linkage control of "deformation-water level-weather" (such as automatically increasing the pressure of the vertical hydraulic cylinder by 10% when the water level rises by 50cm); it can also be connected to the smart construction site platform to realize remote monitoring, data traceability and construction early warning.

[0035] Component reusability: Standard steel columns, hydraulic cylinders, and flange assemblies are all standardized designs (without on-site welding deformation), and can be reused in 5-8 ultra-deep foundation pit projects, reducing material costs by more than 60%, which is in line with the concept of green construction.

[0036] 6. Achieving a win-win situation in terms of control precision and economy, reducing the overall cost of ultra-deep foundation pits. Traditional support systems rely on repeated manual adjustments (each adjustment costs over 50,000 yuan) and are prone to rework due to deformation exceeding limits. This invention achieves cost reduction and efficiency improvement through intelligent control.

[0037] Labor costs reduced by 70%: Replacing manual monitoring and adjustment, the central control unit can simultaneously manage 30-50 sets of hydraulic cylinders, reducing on-site monitoring personnel by 6-8 people per day.

[0038] Zero rework costs: Closed-loop feedback control keeps the deformation of the foundation pit within the allowable range of the specifications (such as side wall displacement ≤10mm), avoiding rework costs such as support reinforcement and surrounding building repair due to excessive deformation (saving 200,000 to 500,000 yuan per project).

[0039] Equipment cost optimization: Fuzzy PID algorithm reduces the start-stop frequency of hydraulic cylinders (by 30%), extends equipment life (from 3 years to 5 years), and reduces equipment maintenance costs by 40%. Attached Figure Description

[0040] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0041] Figure 1 This is a top view of the structure of the present invention; Figure 2 for Figure 1 Cross-sectional view; Figure 3 for Figure 1 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view of point B in the middle; Figure 5 This is a control principle diagram of the present invention.

[0042] Explanation of icon numbers: 1. Concrete retaining wall for foundation pit; 2. Horizontal embedded steel column; 3. Longitudinal embedded steel column; 4. Vertical embedded steel column; 5. Standard steel column; 6. Steel structure spatial node; 7. Foundation pit raft foundation; 8. Flange assembly; 9. Edge building. 61. Horizontal hydraulic cylinder, 62. Longitudinal hydraulic cylinder, 63. Vertical hydraulic cylinder, 64. Stroke sensor, 65. Edge space node, 66. Middle space node; Flange 81, high-strength bolts 82. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the core concept of the present invention and the following embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] These embodiments are provided to make the application thorough and complete, and to fully express the scope of the application to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​illustrated in these embodiments should be interpreted as merely exemplary and not as limiting.

[0045] It should be noted that, in the description of this application, unless otherwise stated, "several" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "axial," "radial," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0046] Furthermore, the terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0047] It should also be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0048] All terms used in this application have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0049] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0050] An adaptive multi-directional hydraulic foundation pit support system for ultra-deep foundation pits and its dynamic control method, such as Figures 1 to 5 As shown, this includes horizontally embedded steel columns 2 and longitudinally embedded steel columns 3 pre-embedded in the concrete retaining wall 1 of the foundation pit, and vertically embedded steel columns 4 pre-embedded in the raft foundation 7 of the foundation pit. Specifically, the horizontally embedded steel columns 2 and longitudinally embedded steel columns 3 are all pre-embedded in the sidewalls of the concrete retaining wall 1 of the foundation pit, and the axes of all the horizontally embedded steel columns 2 and longitudinally embedded steel columns 3 are in the same horizontal plane. The horizontally embedded steel columns 2 are pre-embedded in the width direction of the sidewalls of the concrete retaining wall 1 of the foundation pit, and the longitudinally embedded steel columns 3 are pre-embedded in the length direction of the concrete retaining wall 1 of the foundation pit. The vertically embedded steel columns 4 are pre-embedded in the raft foundation 7 of the foundation pit, and their axes are arranged vertically and perpendicular to the horizontal plane.

[0051] The horizontally embedded steel columns 2, longitudinally embedded steel columns 3, and vertically embedded steel columns 4 are each connected to the steel structure space node 6 via corresponding standard steel columns 5. That is, the steel structure space node 6 serves as a connecting hub, with the horizontally embedded steel columns 2, longitudinally embedded steel columns 3, and vertically embedded steel columns 4 all connected to the steel structure space node 6 via their respective standard steel columns 5. These three elements form a mutually perpendicular horizontal, longitudinal, and vertical intersecting structure: the horizontally embedded steel columns 2 and their corresponding standard steel columns 5; the longitudinally embedded steel columns 3 and their corresponding standard steel columns 5; and the vertically embedded steel columns 4 and their corresponding standard steel columns 5.

[0052] The steel structure space node 6 includes a transverse hydraulic cylinder 61, a longitudinal hydraulic cylinder 62, and a vertical hydraulic cylinder 63, which are respectively connected to the standard steel columns 5 in each direction. That is, the transverse hydraulic cylinder 61, the longitudinal hydraulic cylinder 62, and the vertical hydraulic cylinder 63 in the steel structure space node 6 can compensate for transverse, longitudinal, and vertical deformations, respectively.

[0053] The transverse hydraulic cylinder 61, longitudinal hydraulic cylinder 62, and vertical hydraulic cylinder 63 are all connected to pressure sensors. These sensors dynamically monitor changes in support force in each direction, facilitating adjustment of the extension of each cylinder. Each cylinder is also connected to a stroke sensor 64, which monitors the extension of the corresponding cylinder in real time, enabling rapid response and precise adjustment. Based on the sensor data, the central control unit uses a fuzzy PID algorithm to calculate the required compensation force in each direction in real time, driving the corresponding hydraulic cylinders to dynamically adjust the support reaction force.

[0054] It should be noted that the forming sensor 64 used for the hydraulic cylinder, like the hydraulic cylinder itself, is existing technology. Those skilled in the art can choose various stroke sensors suitable for practical use, and this embodiment will not elaborate further.

[0055] Preferably, the steel structure spatial node 6 is located in the vertical plane of the structure in the width direction of the foundation pit, and a plurality of steel structure spatial nodes 6 are provided along the length direction of the foundation pit.

[0056] Preferably, the transverse embedded steel column 2, the longitudinal embedded steel column 3, and the steel structure space node 6 are at the same height, which is one-third of the depth of the foundation pit.

[0057] Preferably, the steel structure space node 6 includes an adjacent space node 65 and a central space node 66.

[0058] Preferably, the adjacent space node 65 includes two horizontal hydraulic cylinders 61, one vertical hydraulic cylinder 62, and one vertical hydraulic cylinder 63. The two horizontal hydraulic cylinders 61 are connected to the horizontal pre-embedded steel columns 2 on the left and right sides respectively through the standard steel columns 5 on the left and right sides. The vertical hydraulic cylinder 62 is connected to the vertical pre-embedded steel column 3 near the edge through the corresponding standard steel column 5. The vertical hydraulic cylinder 63 is connected to the vertical pre-embedded steel column 4 at the bottom through the standard steel column 5 below.

[0059] Preferably, the central space node 66 includes two horizontal hydraulic cylinders 61, two vertical hydraulic cylinders 62, and one vertical hydraulic cylinder 63. The two horizontal hydraulic cylinders 61 are connected to the horizontal pre-embedded steel columns 2 on the left and right sides respectively through the standard steel columns 5 on the left and right sides. The two vertical hydraulic cylinders 62 are connected to the adjacent edge space node 65 respectively through the corresponding standard steel columns 5. The vertical hydraulic cylinder 63 is connected to the vertical pre-embedded steel column 4 at the bottom through the standard steel column 5 below.

[0060] Preferably, each embedded steel column is connected to an adjacent standard steel column 5, adjacent standard steel columns 5 are connected to each other, and each hydraulic cylinder is connected to an adjacent standard steel column 5 via a flange assembly 8. The flange assembly 8 includes two identical flanges 81, which are welded to the two structures to be connected, and then the two flanges 81 are connected by a number of high-strength bolts 82.

[0061] Preferably, the steel structure space node 6 includes a cubic body, and the hydraulic cylinder barrels of each hydraulic cylinder are respectively connected to the corresponding structural surface of the cubic body through flange assembly 8.

[0062] A dynamic control method for an ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system is proposed. The system employs the aforementioned ultra-deep foundation pit adaptive multi-directional hydraulic foundation pit support system. The central control unit establishes a three-dimensional dynamic model of foundation pit deformation by fusing various data, and calculates the deformation compensation requirements in each direction (lateral, longitudinal, and vertical) in real time.

[0063] Preferably, a force-displacement coordinated control algorithm is adopted: the horizontal, longitudinal, and vertical hydraulic cylinders are divided into linkage groups, and the output ratio of each hydraulic cylinder is optimized and allocated through the objective function to ensure that the vector superposition of the three-dimensional compensation forces is consistent with the actual deformation direction of the foundation pit.

[0064] Preferably, the linkage logic adopts a master-slave control strategy: the direction with the largest deformation is the master control direction, and the other directions are the slave directions. The compensation force of each hydraulic cylinder is dynamically adjusted by a preset weight coefficient to avoid stress concentration in other directions due to overcompensation in a single direction.

[0065] Preferably, a dynamic priority mechanism is used: when the deformation rate in a certain direction exceeds a threshold, the system automatically increases the response priority of the hydraulic cylinder in that direction, while reducing the compensation amplitude in other directions to achieve dynamic balance.

[0066] Preferably, a closed-loop feedback mechanism is used: the displacement and pressure sensor data of each hydraulic cylinder are fed back to the central control unit in real time, and the compensation force is iteratively corrected by the fuzzy PID algorithm to form a closed-loop control of "monitoring-calculation-execution-verification" to ensure the coordination and real-time performance of the three-dimensional compensation force.

[0067] As a preferred embodiment 1: an ultra-deep subway foundation pit in a soft soil area of ​​Shanghai (a station on Line 18). 1. Project Background and Technical Requirements Excavation pit parameters: rectangular cross section (length 130m, width 26m, excavation depth 26m), located in a soft soil area (clay layer thickness 20m, moisture content 35%), adjacent to a 10-story old residential building (closest distance 2.5m) and an underground water supply pipeline (burial depth 3m).

[0068] Core requirements: During the excavation and replacement of the support, the maximum displacement of the sidewall should be ≤10mm, the settlement of the residential building should be ≤5mm, and the displacement of the pipeline should be ≤3mm. The replacement period should be ≤8 days (18 days for traditional support). It is necessary to adapt to the characteristics of "slow deformation and large settlement" caused by the high compressibility of soft soil.

[0069] 2. System Composition and Parameter Design (1) Hardware support system Component type Specifications Material / Selection Horizontal / Longitudinal / Vertical Embedded Steel Columns The cross-section is H350×350×12×19, and the length is 1.8m (1.2m for the embedded end and 0.6m for the exposed end). Q355ND (Low-temperature toughness steel, suitable for Shanghai winters) Standard steel column Lateral: Length 8-8.5m (adapted to the width of the excavation pit); Longitudinal: Length 7-7.5m; Vertical: Length 18m Q355ND, surface epoxy zinc-rich anti-corrosion (thickness 80μm) hydraulic cylinder Lateral: Stroke 500mm, rated thrust 1200kN, cylinder diameter 220mm, rod diameter 160mm; Longitudinal: Stroke 300mm, rated thrust 800kN; Vertical: Stroke 400mm, rated thrust 1500kN Cylinder block: 35CrMo; Piston rod: 27SiMn; Seals: Nitrile rubber (oil resistant). sensor Pressure sensor: measuring range 0-2000kN, accuracy ±0.5%FS; Stroke sensor: measuring range 0-500mm, accuracy ±0.5mm Pressure: PT124G-20MPa; Stroke: KTC-1A Flange assembly 25mm thickness, φ26 bolt holes, 8 sets of M24 high-strength bolts (grade 10.9, preload torque 550 N·m), with 3mm weather-resistant rubber gaskets between flanges. Q355B, bolt surface treated with Dacromet coating Central control unit PLC model S7-1500, 10-inch touchscreen, supports 485 bus and 4G remote transmission. Integrated fuzzy PID control module (2) Node layout A total of 33 steel structure spatial nodes are set up, with 1 group every 8m along the length of the foundation pit, located on the vertical plane in the width direction.

[0070] The 65th set of 17 adjacent space nodes (near the residential building) is equipped with "double horizontal + single longitudinal + single vertical" hydraulic cylinders.

[0071] The central space node consists of 16 groups, equipped with "double transverse + double longitudinal + single vertical" hydraulic cylinders.

[0072] 3. Dynamic control implementation process This embodiment focuses on the stage when the foundation pit is excavated to a depth of 20m (replacing the second support with the third support), and the dynamic control is executed in 4 steps.

[0073] (1) Preliminary modeling and parameter setting The central control unit establishes a three-dimensional deformation model of the foundation pit using BIM+FLAC3D, inputs the physical parameters of the soft soil (cohesion c=18kPa, internal friction angle φ=15°), and pre-calculates the deformation thresholds for each construction stage: lateral displacement ≤10mm, longitudinal displacement ≤8mm, vertical displacement ≤6mm, and deformation rate threshold ≤0.5mm / h.

[0074] Set the fuzzy PID parameters as follows: horizontal hydraulic cylinder (edge ​​side) Kp=2.8, Ki=1.0, Kd=0.4 (the integral coefficient needs to be increased for slow deformation of soft soil), longitudinal Kp=2.2, Ki=0.7, Kd=0.3, vertical Kp=2.5, Ki=0.9, Kd=0.35.

[0075] Define the master-slave control logic: take the lateral deformation of the adjacent side as the master control direction (weight 0.6), and the longitudinal (weight 0.3) and vertical (weight 0.1) directions as slave directions.

[0076] (2) Real-time monitoring and deformation early warning The pressure / stroke sensor collects data once every 100ms. When the excavation of the foundation pit reaches 20m, the lateral displacement of the adjacent side reaches 7mm, and the deformation rate rises to 0.6mm / h (exceeding the threshold of 0.5mm / h). The system automatically triggers the dynamic priority mechanism.

[0077] The response priority of the transverse hydraulic cylinder was increased, and the adjustment speed was increased from 5 mm / s to 8 mm / s.

[0078] Reduce the longitudinal hydraulic cylinder compensation force (from 600kN to 480kN) to avoid the longitudinal stress superposition leading to increased lateral deformation.

[0079] (3) Force-displacement coordinated regulation The central control unit calculates the compensation requirements using a fuzzy PID algorithm: the lateral extension needs to be increased by an additional 12mm, and the pressure needs to be increased to 1000kN.

[0080] Force-displacement coordinated control algorithm optimizes output: dual lateral hydraulic cylinders extend synchronously by 12mm (error ≤ 0.5mm), and vertical hydraulic cylinder pressure is maintained at 1200kN (to offset the effect of pit bottom bulge on lateral deformation).

[0081] Driven direction linkage: The longitudinal hydraulic cylinder adaptively shortens by 5mm according to the lateral adjustment amount to ensure the overall force balance of the foundation pit.

[0082] (4) Closed-loop feedback and verification After adjustment, the sensor feedback showed that the lateral displacement decreased to 6 mm and the deformation rate decreased to 0.3 mm / h.

[0083] The central control unit continuously monitors for 2 hours, confirms that the deformation is stable (fluctuation ≤0.5mm), automatically exits the priority mode, and resumes normal control logic.

[0084] 4. Implementation effect verification Deformation control: The maximum displacement of the sidewall of the foundation pit throughout the entire cycle is 8.5mm (requirement ≤10mm), the settlement of the residential building is 4.2mm (requirement ≤5mm), and the displacement of the pipeline is 2.8mm (requirement ≤3mm), which is far superior to traditional support.

[0085] Construction efficiency: The replacement of the 2nd and 3rd supports only takes 7 days (traditionally 18 days), shortening the construction period by 61% and eliminating the need for work stoppages for reinforcement.

[0086] Economic efficiency: Standard steel columns and hydraulic cylinders can be reused in the Shanghai Metro Line 21 project, reducing material costs by 65% ​​and labor costs by 72%.

[0087] As a preferred embodiment 2: an ultra-deep high-rise building basement foundation pit in a coastal area of ​​Shenzhen 1. Project Background and Technical Requirements Excavation pit parameters: rectangular cross section (length 80m, width 32m, excavation depth 22m), located in the coastal area of ​​Shenzhen Bay (groundwater level 1.5m deep, significant influence of seawater tides, soil chloride concentration 0.8%). Core requirements: resistance to seawater corrosion and seepage, foundation pit deformation ≤12mm, support system can dynamically adapt to changes in water level (tidal fluctuations cause water level fluctuations of ±0.5m), and replacement of supports within 10 days.

[0088] 2. System optimization and dynamic control adjustment (1) Hardware optimization (for coastal environments) The hydraulic cylinder and embedded steel column are made of 316L stainless steel (resistant to chloride salt corrosion), and the flange assembly is equipped with a nitrile rubber waterstop ring (anti-seepage grade P6).

[0089] A new water level sensor (range 0-5m, accuracy ±10mm) is added and connected to the central control unit to achieve linkage between water level and hydraulic cylinder pressure.

[0090] (2) Control algorithm adjustment When the tide causes the water level to rise by 0.5m, the soil pressure increases by 15%, and the system automatically increases the pressure of the transverse hydraulic cylinder by 15% (from 900kN to 1035kN) to avoid a sudden increase in deformation.

[0091] Fuzzy PID parameter optimization: Due to the fast deformation rate of coastal soil (sand and clay), the integral coefficient Ki is reduced to 0.6, the derivative coefficient Kd is increased to 0.5, and the response time is shortened to 0.3s.

[0092] 3. Implementation Results Corrosion and seepage resistance: After 6 months of system operation, the hydraulic cylinders showed no rust and the flange connections showed no water leakage (traditional steel supports showed rust after 3 months).

[0093] Water level adaptation: When the tidal water level fluctuates, the deformation of the foundation pit is stable at 9-11mm (requirement ≤12mm), and the adjustment response is timely.

[0094] Construction period and cost: The replacement of the support structure takes 9 days (traditionally 15 days), and the components can be reused in another coastal project in Shenzhen, reducing the overall cost by 58%.

[0095] III. Summary of Implementation Examples The core advantage of this invention lies in the deep integration of "hardware-supported three-dimensional adjustability" and "software-controlled intelligent dynamism": In soft soil areas, by adapting the fuzzy PID algorithm to the slow deformation characteristics, the deformation control accuracy reaches ±0.5mm; In coastal areas, corrosion and seepage problems are solved by optimizing hardware corrosion protection and linking water level control. Both scenarios achieved a reduction of over 50% in construction period and over 60% in deformation, verifying the universality and advancement of the invention in complex scenarios of ultra-deep foundation pits. It can be widely promoted to ultra-deep foundation pit projects such as subways, super high-rise buildings, and utility tunnels.

[0096] Finally, it should be noted that the parts not described in detail in the above embodiments are all common knowledge known to those skilled in the art.

[0097] The above content shows and describes the basic principles, main features, and beneficial effects of the present invention. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-adaptive multi-directional hydraulic foundation pit support system for an ultra-deep foundation pit, characterized in that: The steel structure space node (6) is located in the vertical plane of the structure in the width direction of the foundation pit, and the steel structure space node (6) is provided with a plurality of steel structure space nodes along the length direction of the foundation pit.

2. The self-adapting multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 1, characterized in that: The lateral pre-embedded steel column (2), the longitudinal pre-embedded steel column (3) and the steel structure space node (6) are at the same height, and the height is one third of the depth of the foundation pit.

3. The self-adapting multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 2, characterized in that: The steel structure space node (6) includes a marginal space node (65) and a middle space node (66).

4. The self-adapting multi-directional hydraulic foundation pit support system for super-deep foundation pit according to any one of claims 1-3, characterized in that: The marginal space node (65) includes two lateral hydraulic cylinders (61), one longitudinal hydraulic cylinder (62) and one vertical hydraulic cylinder (63), the two lateral hydraulic cylinders (61) are connected with the lateral pre-embedded steel columns (2) on the left and right sides through the standard steel columns (5) on the left and right sides, the longitudinal hydraulic cylinder (62) is connected with the longitudinal pre-embedded steel column (3) near the edge through the corresponding standard steel column (5), and the vertical hydraulic cylinder (63) is connected with the vertical pre-embedded steel column (4) at the bottom through the standard steel column (5) below.

5. The self-adapting multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 4, characterized in that: The middle space node (66) includes two lateral hydraulic cylinders (61), two longitudinal hydraulic cylinders (62) and one vertical hydraulic cylinder (63), the two lateral hydraulic cylinders (61) are connected with the lateral pre-embedded steel columns (2) on the left and right sides through the standard steel columns (5) on the left and right sides, the two longitudinal hydraulic cylinders (62) are connected with the adjacent marginal space nodes (65) through the corresponding standard steel columns (5), and the vertical hydraulic cylinder (63) is connected with the vertical pre-embedded steel column (4) at the bottom through the standard steel column (5) below.

6. The self-adapting multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 5, characterized in that: Each pre-embedded steel column and the adjacent standard steel column (5), the adjacent standard steel columns (5) and each hydraulic cylinder and the adjacent standard steel column (5) are connected through a flange assembly (8).

7. The self-adapting multi-directional hydraulic excavation bracing system for ultra-deep excavation of any one of claims 1-3, 5-6, wherein: The steel structure space node (6) includes a cubic main body, and the hydraulic cylinder barrels of each hydraulic cylinder are connected on the corresponding structure surface of the cubic main body through the flange assembly (8).

8. The self-adapting multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 7, characterized in that: The super-deep foundation pit self-adaptive multi-directional hydraulic foundation pit support system adopts the three-dimensional dynamic model of the foundation pit deformation established by the central control unit through each data fusion, and calculates the deformation compensation demand in the lateral, longitudinal and vertical directions in real time.

9. A dynamic control method of an adaptive multi-directional hydraulic foundation pit support system for an ultra-deep foundation pit, characterized in that: ​ 10. The dynamic control method of the self-adaptive multi-directional hydraulic foundation pit support system for ultra-deep foundation pit according to claim 9, characterized in that: Adopt force-displacement collaborative control algorithm: divide the lateral, longitudinal and vertical hydraulic cylinders into linkage groups, optimize the output proportion of each hydraulic cylinder through the target function, and ensure that the vector superposition of three-direction compensation force is consistent with the actual deformation direction of the foundation pit; The linkage logic adopts master-slave control strategy: the direction with the largest deformation is the master control direction, and the remaining directions are the slave directions. The compensation force of each hydraulic cylinder is dynamically adjusted through the preset weight coefficient to avoid stress concentration in other directions caused by over-compensation in a single direction; Dynamic priority mechanism: when the deformation rate of a certain direction exceeds the threshold, the system automatically raises the response priority of the hydraulic cylinder in that direction, while reducing the compensation amplitude of other directions to achieve dynamic balance; Closed-loop feedback mechanism: the displacement sensor and pressure sensor data of each hydraulic cylinder are fed back to the central control unit in real time, and the compensation force is iteratively corrected through fuzzy PID algorithm to form a "monitoring-computing-executing-verification" closed-loop control, ensuring the collaboration and real-time performance of three-direction compensation force.

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