Prestressed profile steel supporting system and method considering soil stress change synergy

Abstract

The invention relates to the technical field of deep foundation pit supporting, and particularly discloses a prestressed profile steel supporting system and method considering soil stress change collaboration, and the system comprises a supporting structure, a monitoring sensing unit, a central control unit and a servo tensioning device. The supporting structure is composed of supporting piles which are arranged in rows and internally provided with prestressed profile steel components. The monitoring sensing unit is composed of displacement sensor arrays installed on the same elevation of the whole row of support piles. After the central control unit receives the data, a pile row transverse displacement matrix is formed according to a spatial sequence, and differentiated prestress control instructions are generated based on matrix analysis; and the servo tensioning device executes the instruction to perform tensioning operation on the corresponding prestressed profile steel member. The overall deformation information of the row piles is obtained through the displacement monitoring array, independent, accurate and cooperative control over the prestress of all the piles is achieved through displacement matrix analysis, therefore, the stress change of the soil body is effectively dealt with, and the overall safety, control accuracy and economical efficiency of deep foundation pit supporting are improved.

Description

Technical Field

[0001] This invention relates to the field of deep foundation pit support technology, and in particular to a prestressed steel support system and method that takes into account the synergistic effect of soil stress changes. Background Technology

[0002] In traditional foundation pit support design, the design of support piles is mostly based on the stress and deformation calculations of individual piles. However, in actual engineering, support piles are usually arranged in rows, and their stress and deformation are significantly affected by a variety of complex factors such as soil heterogeneity, construction sequence, and local weak layers. This leads to significant differences in deformation at different pile locations, with some piles displacing significantly into the pit while others displace very little, exhibiting a clear spatial distribution characteristic in the actual displacement. Traditional single-pile calculation and monitoring methods are insufficient to accurately reflect the overall stress state of the support structure, and therefore cannot reliably determine the overall safety of the foundation pit.

[0003] To address the aforementioned issues, prestressed steel retaining pile technology has emerged. Its core principle involves placing tensionable prestressed steel members on the outer side of the retaining pile after it has been formed. By applying active prestressing force, this technology can preemptively offset some of the lateral thrust from the soil before the pile undergoes excessive displacement, placing the pile under controlled stress. This allows the retaining structure to enter its working state earlier, effectively reducing soil displacement, controlling foundation pit deformation, and improving the overall stability of the retaining system. In practical applications, the prestressed steel is typically arranged vertically along the pile and tensioned in stages through the top anchorage end to adapt to changes in soil pressure at different excavation stages, achieving matched active control.

[0004] However, existing prestressed steel pile support technology still has limitations. Its prestressing tensioning strategy is typically designed and implemented only for the deformation control of a single pile, failing to fully consider the influence of pile group interactions. During tensioning, the force exerted by the steel on the soil alters the stress field of the surrounding soil, which further affects the earth pressure distribution acting on adjacent prestressed steel piles. This results in the stress conditions of adjacent piles deviating from the original design assumptions, causing the established prestressing tensioning strategy to become inaccurate and failing to achieve the expected overall coordinated control effect, potentially impacting the final safety and economy of the foundation pit support.

[0005] Therefore, how to optimize the design and tension control methods of prestressed steel support piles under actual pile group layout conditions, so as to fully consider the pile-soil-pile interaction, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] Traditional methods often rely solely on the stress and deformation of a typical support pile for design, failing to reflect the coordinated deformation characteristics of a row of piles during excavation due to changes in soil stress. This results in insufficient overall safety assessment of the support system and a lack of targeted and quantitative basis for prestressing application.

[0007] The present invention aims to provide a prestressed steel support system and method that takes into account the synergistic effect of soil stress changes, and to solve the technical defects of "single pile design assumption" and "no synergistic control" that are common in existing foundation pit support systems.

[0008] As a first aspect of the present invention, the present invention provides a prestressed steel support system that considers the synergistic effect of soil stress changes, comprising: a support structure including a plurality of support piles arranged in a row along the sidewall of a foundation pit, each of the support piles having a prestressed steel component inside; a monitoring and sensing unit including a displacement monitoring array consisting of at least one displacement sensor installed at the same predetermined elevation of the row of support piles, for real-time monitoring of the displacement data of each support pile; a central control unit connected to the monitoring and sensing unit, for receiving and processing the displacement data, forming a lateral displacement matrix of the pile row according to the spatial order of each support pile, and generating prestressing control commands based on the analysis results of the displacement matrix; and a servo tensioning device connected to each of the prestressed steel components, for receiving and executing the prestressing control commands issued by the central control unit, and performing tensioning operations on the corresponding prestressed steel components.

[0009] Optionally, the prestressed steel member includes a vertically arranged steel body, an anchoring end located at the upper end of the steel body, a fixed end located at the lower end of the steel body, and a prestressed steel strand tensioned between the anchoring end and the fixed end, wherein the anchoring end is connected to the servo tensioning device.

[0010] Optionally, the displacement sensor is one or more of a linear displacement sensor, a fiber optic grating displacement meter, and a micro MEMS displacement meter.

[0011] Optionally, the prestressed steel support system also includes a monitoring ear plate located on the outside or top of the prestressed steel member. One end of the monitoring ear plate is connected to the support pile, and the other end is connected to the displacement sensor. The ear plate is used to amplify the minute displacement of the support pile and transmit it to the displacement sensor through the lever amplification principle.

[0012] Optionally, the central control unit is configured to: automatically identify and determine risk points where local deformation exceeds the threshold based on the displacement monitoring array, determine the state of enhanced soil stress release caused by foundation pit excavation, and determine the pile row section with insufficient coordinated deformation.

[0013] As a second aspect of the present invention, the present invention provides a prestressed steel support method that considers the synergistic effect of soil stress changes. Based on the prestressed steel support system considering the synergistic effect of soil stress changes described in the first aspect above, the method includes the following steps:

[0014] Real-time monitoring steps: Displacement data of each support pile in the row of support piles is collected at a preset period using a displacement monitoring array.

[0015] Matrix analysis steps: The central control unit arranges the displacement data according to the spatial order of the support piles to form a real-time updated pile row lateral displacement matrix, and analyzes the distribution characteristics of the displacement based on the matrix;

[0016] Decision and control steps: The real-time displacement value of each support pile is compared with the preset target control displacement range, and differentiated prestress control commands are generated based on the comparison results. The servo tensioning device is then used to perform tensioning, maintenance, or decompression operations on the prestressed steel components of the corresponding support piles, forming a closed-loop control.

[0017] Furthermore, in the decision-making and control steps, the control modes executed based on the comparison results include:

[0018] Dynamic incremental tensioning mode: When the displacement value of a support pile exceeds the preset warning threshold, the deviation between it and the target control value is calculated, and an instruction to apply incremental tension force to the support pile is generated.

[0019] Maintenance and fine-tuning mode: When the displacement value of a support pile stabilizes within the target controllable range, a command is generated to maintain the current prestress or to make a small-amplitude compensatory fine-tuning.

[0020] Pressure reduction or pause mode: When the displacement value of a support pile is continuously lower than the lower limit of the controllable range, a command to reduce or pause tensioning is generated.

[0021] Furthermore, in the dynamic incremental tensioning mode, the range of a single incremental tensioning force is 5kN to 20kN.

[0022] Furthermore, the preset target control displacement range includes a controllable range, an early warning threshold, and a mandatory intervention upper limit, the values ​​of which are determined comprehensively based on the engineering safety level, geological conditions, and design specifications.

[0023] Furthermore, in the matrix analysis step, the analysis of the lateral displacement matrix of the pile row is based on logical comparison, including: identifying risk points where the displacement value is significantly greater than that of adjacent piles; determining whether the displacement value of the entire matrix continues to increase to reflect the release of soil stress; and calculating the dispersion of displacement values ​​in different sections to assess the state of coordinated deformation.

[0024] Compared with the prior art, the present invention discloses at least the following beneficial effects:

[0025] The prestressed steel support system and method provided by this invention, through a displacement monitoring array arranged on the entire row of support piles, achieves for the first time synchronous, real-time, and comprehensive perception of the spatial deformation state of the support pile group, overcoming the limitations of traditional single-point monitoring. The central control unit constructs the collected displacement data into a lateral displacement matrix of the pile row in spatial order. This data structure enables the system to intuitively capture and quantify the spatial distribution characteristics and collaborative behavior of deformation from a holistic perspective, providing an unprecedented global information foundation for control decisions. Based on the real-time analysis results of this displacement matrix, the central control unit generates differentiated prestressed control commands, driving the servo tensioning device to independently and precisely regulate each prestressed steel component. This closed-loop control mechanism enables the system to actively and dynamically adjust the prestress level of each pile according to the real-time feedback of the overall deformation state, thereby achieving collaborative, adaptive, and intelligent control of the deformation of the deep foundation pit pile support system, significantly improving the overall stability, safety, and control accuracy of the support structure under complex soil stress variation conditions. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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.

[0027] Figure 1 A schematic diagram of a prestressed steel support system that considers the synergistic effect of soil stress changes, provided in an embodiment of the present invention;

[0028] Figure 2 This is a structural schematic diagram of a prestressed steel member in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram illustrating the application of support piles in an embodiment of the present invention;

[0030] Reference numerals: 100, foundation pit; 200, support pile; 300, prestressed steel component; 301, steel body; 302, anchoring end; 303, fixed end; 304, prestressed steel strand; 400, displacement sensor. Detailed Implementation

[0031] 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 embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide a prestressed steel support system and method that considers the synergistic changes in soil stress. By sensing and utilizing the spatial consistency and differences in the overall deformation of the pile, the application and control of prestressed steel based on the actual deformation behavior can be achieved, thereby improving the safety, accuracy and economy of deep foundation pit support.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] Reference Figures 1 to 3 As shown, this embodiment provides a prestressed steel support system that considers the synergistic effects of soil stress changes. This system is mainly applied in the support engineering of foundation pit 100, used for coordinated, dynamic, and precise active deformation control of the rows of support piles 200. This system abandons the traditional model relying on single-pile calculations and passive reinforcement, and achieves intelligent control based on the overall displacement state of the pile row by integrating sensing, execution, and control units.

[0036] Specifically, the support system mainly includes a support structure, a monitoring and sensing unit, a servo tensioning device, and a central control unit.

[0037] In this embodiment, the support structure includes a row of vertical support piles 200 constructed along the designed excavation depth direction of the sidewall of the foundation pit 100. These support piles 200 are typically made of reinforced concrete and constitute the main retaining and bearing structure during the excavation of the foundation pit 100. In this row of support piles 200, each support pile 200 has a prestressed steel member 300 installed inside as a core support and control component.

[0038] Specifically, such as Figure 2 As shown, the prestressed steel member 300 includes a steel body 301, an anchoring end 302, a fixed end 303, and prestressed steel strands 304. The anchoring end 302 and the fixed end 303 are fixedly connected (e.g., by welding or high-strength bolts) to both ends of the steel body 301. The anchoring end 302 is located at the pile top or between piles and is exposed, used for connection to an external servo tensioning device; the fixed end 303 is located at the other end of the pile and provides reaction support. One or more high-strength prestressed steel strands 304 are tensioned between the anchoring end 302 and the fixed end 303. Applying tension to the anchoring end 302 through the servo tensioning device causes the prestressed steel strands 304 to be under tension, thereby transferring the active prestress through the steel body 301 to the entire support pile 200, allowing it to generate favorable pre-deformation before the earth pressure acts, offsetting part of the subsequent load and achieving active suppression of deformation.

[0039] In one specific embodiment, the steel body 301 is a metal profile with high bending stiffness, such as H-beams or I-beams, preferably made of low-alloy high-strength structural steel such as Q355B, to ensure sufficient load-bearing capacity and durability.

[0040] Furthermore, after the concrete of the support pile 200 reaches the design strength, the steel body 301 of the prestressed steel member 300 is vertically inserted and penetrates the main stress area of ​​the pile.

[0041] In this embodiment, the servo tensioning device is connected to each of the prestressed steel members 300 and is used to receive and execute the prestress control command issued by the central control unit to perform tensioning operation on the corresponding prestressed steel members 300.

[0042] In one specific embodiment, the servo tensioning device can be a common drive structure or mechanical device capable of realizing linear motion / telescopic motion, for example, a hydraulic jack, a hydraulic cylinder, an electric cylinder, etc.

[0043] In this embodiment, the monitoring and sensing unit is responsible for sensing the deformation state of the entire row of support piles 200 in real time. For example... Figure 1 and Figure 3 As shown, at the same preset elevation (e.g., 2 meters below the top of the pile) of the row of support piles 200, at least one displacement sensor 400 is installed for each support pile 200. These displacement sensors 400 together constitute a continuous, synchronous, high-precision displacement monitoring array.

[0044] Based on the above embodiments, the displacement sensor 400 further includes a linear displacement sensor 400 (LVDT), a fiber optic grating displacement meter (FBG), or a micro MEMS displacement meter, with a resolution of 0.01 mm to 0.1 mm, which can accurately capture the minute horizontal displacement of the support pile 200 in the direction of the pit.

[0045] Building upon the above embodiments, to further enhance the monitoring sensitivity for minute displacements, a monitoring ear plate (not shown in the figure) made of low-carbon steel or aluminum alloy can be added to the outer side or top of the prestressed steel member 300. This monitoring ear plate has low stiffness, and one end is connected to the support pile 200. When the support pile 200 undergoes minute deformation, the monitoring ear plate amplifies the minute relative displacement between itself and the surface of the support pile 200, converting it into a more significant displacement through leverage and transmitting it to the displacement sensor 400. This effectively increases the signal amplitude detected by the sensor by 2 to 5 times. All displacement sensors 400 are connected to the central control platform via fieldbus or wireless network to achieve real-time synchronous data transmission.

[0046] In this embodiment, the central control unit is the "brain" of the system. Its hardware is typically an industrial computer or a programmable logic controller (PLC), while its software integrates data acquisition, analysis, and control command issuance functions. The central control platform continuously receives data from the displacement monitoring array and arranges it according to the spatial order (chainage) of the 200 support piles, forming a "pile row lateral displacement matrix" that can intuitively reflect the spatial deformation characteristics of the entire row of piles. This matrix is ​​the sole entry point and data foundation for all intelligent analysis and decision-making by the system.

[0047] Example 2

[0048] This invention also provides a prestressed steel support method that considers the synergistic effect of soil stress changes. Based on the prestressed steel support system considering the synergistic effect of soil stress changes described in the above embodiments, the core of this method lies in implementing differentiated closed-loop tension control on the prestressed steel members 300 on each support pile 200 according to the lateral displacement matrix of the pile row, so as to achieve overall synergistic deformation of the pile row. The method specifically includes the following steps:

[0049] The system's operation begins with continuous monitoring. The central control platform automatically reads real-time data from all displacement sensors 400 at preset intervals (e.g., 10 to 30 seconds) and updates the displacement matrix D in sequence according to station number. This matrix not only contains the absolute displacement value of each station at each monitoring moment, but also implies the spatial distribution differences and temporal trends of displacement.

[0050] Next, the system performs real-time analysis of the displacement matrix D. This analysis is based on direct and explicit logical comparison, without the need for complex mathematical models. The system automatically identifies three key states: First, when the displacement value of a specific pile number in the matrix is ​​significantly greater than the displacement values ​​of its left and right adjacent piles, the system determines that this is a "risk point" with excessive local deformation; second, when the displacement values ​​of the entire matrix show a consistent increasing trend over several consecutive monitoring time points, the system determines that the current excavation activity of the foundation pit 100 has led to enhanced soil stress release; third, if the difference (dispersion) of the displacement values ​​of each pile in a certain continuous section of the matrix is ​​significantly greater than that in other sections, the system determines that there is a problem of "insufficient coordinated deformation" in that section.

[0051] Based on the analysis, the system enters the decision-making stage. The decision is based on comparing the real-time displacement values ​​of each measuring point with the pre-set "target control displacement range". This range is determined comprehensively based on the engineering safety level, geological conditions and design specifications. For example, 2mm to 6mm can be set as the ideal "controllable range", 8mm to 10mm as the "early warning threshold" and 12mm to 15mm as the "forced intervention upper limit".

[0052] Based on the comparison results, the system automatically generates and issues corresponding control commands to drive the servo tensioning device to perform precise operations, forming a complete control closed loop. Its control strategy is specifically manifested in three modes:

[0053] Dynamic incremental tensioning mode: When the displacement value of a pile exceeds the warning threshold (e.g., >8mm), the system automatically calculates the deviation between its displacement value and the target control value (e.g., the midpoint of the interval 5mm) and generates a control command accordingly to apply an incremental tensioning force to the anchoring end 302 of the prestressed steel member 300 corresponding to the pile. The single incremental value can be set in the range of 5kN to 20kN to quickly suppress the development of deformation.

[0054] Maintenance and fine-tuning mode: When the displacement value of a pile is stable within the target controllable range (2mm to 6mm), the system instructs its corresponding tensioning device to maintain the current prestress level, or to make only a very small amount of compensatory fine-tuning (such as ±1kN) to maintain the stability of the pile's deformation state.

[0055] Pressure Reduction or Pause Mode: If the system detects that the displacement value of a pile is consistently below the lower limit of the controllable range (e.g., <2mm), it indicates that the soil pressure at that location is low or the structural stiffness is excessive. To avoid unnecessary concentration of internal forces in the material and waste of prestress, the system will issue an instruction to appropriately reduce the tension force of the corresponding prestressed steel member 300, or temporarily stop the tensioning operation at that location.

[0056] The aforementioned process of "monitoring and data acquisition—matrix analysis—threshold comparison—command execution" is performed in a fixed cycle. After each control action is executed, the system immediately acquires new displacement data in the next cycle, forms a new displacement matrix, and evaluates the effect of the previous round of control based on the latest state, thereby deciding whether to initiate the next round of adjustment. This process repeats continuously, forming a real-time dynamic closed-loop feedback control mechanism with displacement as the single signal parameter and the matrix as the cooperative perspective.

[0057] By implementing this method, the deformation of the entire row of support piles 200 remains uniform, coordinated, and controllable throughout all construction stages of the foundation pit 100, including excavation, support, and backfilling. This not only effectively overcomes the problem of single-pile response imbalance caused by soil heterogeneity, stress redistribution due to excavation, and construction disturbance, significantly improving the overall stability and safety of the foundation pit 100 sidewalls, but also optimizes resource allocation through differentiated and precise force application, avoiding material waste caused by traditional uniform tensioning, thus achieving both outstanding safety and economic benefits.

[0058] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to 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 of this invention.

[0059] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A prestressed steel support system considering the stress change of soil body in cooperation, characterized in that, The utility model relates to a kind of real-time monitoring and control method of pre-stressed supporting structure of foundation pit, including: Supporting structure, including being arranged in row along the side wall of foundation pit (100) several supporting piles (200), the inside of each described supporting pile (200) is provided with pre-stressed steel member (300); Monitoring sensing unit, including at least one displacement sensor (400) of displacement monitoring array formed by being installed on the same predetermined elevation of the whole row described supporting pile (200), for real-time monitoring the displacement data of each supporting pile (200); Central control unit, connected with the monitoring sensing unit, for receiving and processing displacement data, forming pile row transverse displacement matrix according to the spatial order of each supporting pile (200), and generating pre-stress control instruction based on the analysis result of the displacement matrix; Servo tensioning device, connected with each described pre-stressed steel member (300), for receiving and executing the pre-stress control instruction issued by the central control unit, tensioning operation is carried out on the corresponding pre-stressed steel member (300).

2. The pre-stressed steel support system of claim 1, wherein, The pre-stressed steel member (300) includes a vertically arranged steel body (301), an anchoring end (302) located at the upper end of the steel body (301), a fixed end (303) located at the lower end of the steel body (301), and a pre-stressed steel strand (304) tensioned between the anchoring end (302) and the fixed end (303). The anchoring end (302) is connected with the servo tensioning device.

3. The pre-stressed steel support system of claim 1, wherein, The displacement sensor (400) is one or more of a linear displacement sensor (400), a fiber grating displacement meter, and a micro MEMS displacement meter.

4. The pre-stressed steel support system of claim 3, wherein, It also includes a monitoring ear plate provided on the outside or top end of the pre-stressed steel member (300), one end of the monitoring ear plate is connected to the supporting pile (200), the other end is connected to the displacement sensor (400), and the small displacement of the supporting pile (200) is amplified and transmitted to the displacement sensor (400) through the lever amplification principle.

5. The pre-stressed steel support system of claim 1, wherein, The central control unit is configured to automatically identify and determine the risk points of local deformation exceeding the threshold value, determine the state of stress release enhancement of the soil body due to excavation of the foundation pit (100), and determine the pile row section with insufficient cooperative deformation.

6. A method of prestressed steel support considering the coordination of stress changes in soil bodies, based on the prestressed steel support system considering the coordination of stress changes in soil bodies according to any one of claims 1 to 5, characterized in that, The method includes the following steps: Real-time monitoring step: through the displacement monitoring array, the displacement data of each supporting pile (200) in the row of supporting piles (200) is collected at a preset period; Matrix analysis step: the central control unit arranges the displacement data to form a real-time updated pile row transverse displacement matrix according to the spatial order of the supporting piles (200), and analyzes the distribution characteristics of the displacement based on the matrix; Decision and control step: compare the real-time displacement value of each supporting pile (200) with the preset target control displacement interval, and generate differentiated pre-stress control instructions according to the comparison result, drive the servo tensioning device to perform tensioning, maintenance or decompression operation on the pre-stressed steel member (300) of the corresponding supporting pile (200), and form a closed-loop control.

7. The method of claim 6, wherein the method further comprises, In the decision and control step, the control mode executed according to the comparison result includes: Dynamic incremental tension mode: when the displacement value of a certain support pile (200) exceeds the preset warning threshold, the deviation from the target control value is calculated, and an instruction is generated to apply an incremental tension force to the support pile (200); Maintenance and fine-tuning mode: when the displacement value of a certain support pile (200) is stable within the target controllable interval, an instruction is generated to maintain the current prestress or perform small-scale compensatory fine-tuning; Decompression or suspension mode: when the displacement value of a certain support pile (200) continuously falls below the lower limit of the controllable interval, an instruction is generated to reduce or suspend tension.

8. The method of claim 7, wherein the method further comprises, In the dynamic incremental tension mode, the range of a single incremental tension force is 5kN to 20kN.

9. The method of claim 6, wherein the method further comprises, The preset target control displacement interval includes a controllable interval, a warning threshold, and an upper limit for forced intervention, The values are determined comprehensively according to the engineering safety level, geological conditions, and design specifications.

10. The method of claim 6, wherein the method further comprises, In the matrix analysis step, the analysis of the lateral displacement matrix of the pile row is based on logical comparison, including: identifying risk points with displacement values significantly greater than adjacent pile positions; judging whether the entire matrix displacement value is continuously increasing to reflect soil stress release; and calculating the dispersion of displacement values in different sections to assess the state of coordinated deformation.

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