Tunnel base soft soil deformation precision regulation and reinforcement method

Abstract

The application discloses a tunnel base soft soil deformation precision regulation and reinforcement method, and belongs to the technical field of tunnels and underground engineering. The method comprises the following steps: laying a monitoring unit, a bag grouting device and an electro-osmotic electrode system; a control system acquires real-time three-dimensional displacement data and dynamically compares the displacement data with deformation control indexes, wherein the deformation control indexes comprise a target control interval and a deformation safety threshold; when the displacement data exceeds the target control interval, bag expansion grouting is performed to lift the tunnel structure; electro-osmosis drainage is synchronously performed during grouting to accelerate the dissipation of excess pore water pressure; and when the displacement data reaches or approaches the deformation safety threshold, grouting is suspended and electro-osmosis drainage is maintained or enhanced. The application realizes deformation precision regulation and control through a closed-loop system of monitoring, distinguishing, executing, feeding back and adjusting, effectively inhibits the post-grouting stratum reconsolidation settlement, and guarantees long-term stability of the tunnel.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering technology, and more specifically, to a method for reinforcing the foundation of tunnels in soft soil strata, particularly a method for reinforcing soft soil strata that addresses real-time response to tunnel deformation and enables precise control of deformation. Background Technology

[0002] With the increasing intensity of urban underground space development, shield tunnels have become an important part of urban transportation networks. However, in the widely distributed soft clay strata, shield tunnels are prone to uneven settlement or excessive convergence deformation during construction and long-term operation due to the adverse engineering characteristics of the soil, such as high natural water content, large void ratio, high compressibility, and low shear strength. This seriously threatens structural safety and operational quality.

[0003] To address such issues, the current common practice in the engineering field is to employ foundation grouting reinforcement technology. This involves injecting cement grout or chemical grout into the strata at the bottom of the tunnel. The grout's filling, compaction, and fracturing effects improve soil properties, thereby controlling or restoring tunnel deformation. For monitoring, manual leveling or semi-automated monitoring systems are typically used to acquire tunnel deformation data, which guides the implementation of grouting operations.

[0004] Although existing grouting reinforcement technologies can alleviate tunnel settlement to some extent, significant technical bottlenecks and shortcomings remain in the refined treatment of soft clay strata, mainly in the following three aspects: First, the diffusion behavior of grout in soft clay is difficult to control precisely. Due to the extremely poor permeability of soft clay, traditional grouting processes often require high grouting pressure to inject the grout into the formation. However, excessive grouting pressure can easily cause hydraulic fracturing in the formation, resulting in the grout spreading disorderly along the weak points of the soil and failing to form an effective reinforcement core in the target area. This disorder not only significantly reduces reinforcement efficiency but may also cause unnecessary secondary disturbance to surrounding existing pipelines or formations, leading to great uncertainty in deformation control effects.

[0005] Secondly, existing technologies generally overlook the "negative effects" of grouting disturbance, namely, the reconsolidation settlement caused by the dissipation of excess pore water pressure. Grouting expansion is essentially a forced soil displacement process, which inevitably generates significant excess pore water pressure in low-permeability soft clay. Existing technologies often only focus on the instantaneous uplift effect of grouting, ignoring the inevitable "reconsolidation settlement" that occurs in the strata after grouting as the excess pore pressure gradually dissipates. This delayed settlement phenomenon often offsets part of the reinforcement uplift, and may even cause secondary or repeated deformation of the tunnel structure under long-term effects, leading to a vicious cycle of "grouting-uplift-consolidation-reconsolidation" in the remediation work, accelerating the deterioration of the tunnel structure's performance.

[0006] Finally, the control model for deformation mitigation suffers from severe lag and blindness. Current control strategies rely primarily on manual experience, resulting in passive, non-real-time adjustments. From data collection, manual verification, and transmission to final data analysis, the entire process suffers from significant time delays. This non-real-time feedback mechanism prevents construction personnel from quickly adjusting grouting parameters (pressure, flow rate) based on the instantaneous dynamics of tunnel deformation (such as sudden changes in deformation rate). Especially at night or under unattended conditions, gaps in monitoring information feedback can easily lead to improper parameter adjustments, resulting in engineering risks such as insufficient or excessive uplift (over-adjustment), failing to meet the stringent requirements of modern tunnel operation and maintenance for precise millimeter-level deformation control.

[0007] In summary, existing technologies urgently need a closed-loop control method that can respond in real time to tunnel deformation characteristics, effectively eliminate the negative effects of grouting overpressure, and automatically achieve precise parameter adjustment, in order to solve the problem of "inaccurate control and instability" in the treatment of tunnel deformation in soft soil strata. Summary of the Invention

[0008] The purpose of this invention is to provide a method for precise control and reinforcement of soft soil deformation in tunnel foundations, in order to solve the technical problems in the existing technology of grouting reinforcement of soft soil tunnel foundations, such as disordered diffusion of grout in the stratum and easy induction of splitting disturbance, dissipation of excess pore water pressure generated by grouting leading to ground reconsolidation and settlement, and the slow response and low precision of traditional manual control mode.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A method for precisely controlling and reinforcing soft soil deformation at the tunnel foundation includes the following steps: The system includes a monitoring unit, a bag grouting device, and an electroosmotic electrode system. The monitoring unit is used to collect three-dimensional displacement data of the tunnel, the bag grouting device is used to perform bag expansion grouting, and the electroosmotic electrode system is used to perform electroosmotic drainage.

[0010] By deploying monitoring units, grouting bags, and an electroosmotic electrode system, a complete hardware execution system was established, laying the physical foundation for subsequent closed-loop control. The monitoring units enable real-time sensing of tunnel deformation, the grouting bags act as the lifting actuator, and the electroosmotic electrode system acts as the drainage and consolidation actuator. These three components work together to form the execution layer for deformation regulation.

[0011] The control system acquires the tunnel's three-dimensional displacement data collected in real time by the monitoring unit.

[0012] The control system acquires three-dimensional displacement data collected by the monitoring unit in real time, realizing millisecond-level perception of tunnel deformation status, overcoming the lag problem of traditional manual monitoring, and providing real-time data support for dynamic control.

[0013] The control system dynamically compares the real-time three-dimensional displacement data with preset deformation control indicators. The deformation control indicators include a target control range and a deformation safety threshold. The target control range is the ideal adjustment range for tunnel uplift or settlement. The deformation safety threshold includes at least one of the maximum allowable uplift, the maximum allowable settlement, and the maximum deformation rate.

[0014] A multi-level safety control system was constructed by setting target control ranges and deformation safety thresholds. The target control range defines the ideal deformation regulation range, providing a clear target guidance for reinforcement operations; the deformation safety threshold delineates the safety boundary, triggering a protection mechanism when deformation approaches this boundary, effectively preventing the risk of deformation exceeding limits.

[0015] When the real-time three-dimensional displacement data exceeds the target control range, the control system controls the bag grouting device to perform bag expansion grouting to lift the tunnel structure.

[0016] The bag expansion grouting method applies physical uplift force to the soft soil strata through the controlled expansion of the bags, avoiding the problem of disordered grout diffusion in traditional grouting. The constraint effect of the bags allows the grouting pressure to be applied precisely to the target area, improving reinforcement efficiency and control accuracy.

[0017] During the sac expansion grouting, the control system controls the electroosmotic electrode system to perform electroosmotic drainage to accelerate the dissipation of excess pore water pressure generated during grouting.

[0018] While the grouting process is underway, electro-osmotic drainage is initiated. The electric field force drives the pore water to migrate directionally towards the drainage end, accelerating the dissipation of excess pore water pressure generated by the grouting and soil displacement. This synergistic mechanism of "lifting and draining simultaneously" solves the problem of excess pore pressure accumulation caused by grouting in soft clay from a soil mechanics perspective, effectively inhibiting the reconsolidation and settlement of the strata after grouting.

[0019] When the real-time three-dimensional displacement data reaches or approaches the deformation safety threshold, the control system executes a protection strategy, which includes suspending the bladder expansion grouting and maintaining or enhancing the electroosmotic drainage.

[0020] By introducing an automatic protection strategy, when the deformation rate changes abruptly or the displacement approaches its limit, the system immediately suspends grouting to block the soil squeezing effect, while maintaining or enhancing electroosmosis to strengthen drainage and consolidation, allowing the strata to quickly return to a stable state. This mechanism effectively avoids the risk of tunnel deformation exceeding limits that may be caused by misjudgment during manual operation or by unattended operation at night.

[0021] Furthermore, the monitoring unit includes scanning prisms deployed in key deformation areas of the tunnel structure. The real-time three-dimensional displacement data is acquired by continuously scanning the scanning prisms using a high-precision total station. Its advantages are: by deploying scanning prisms in key deformation areas such as the tunnel segment's arch crown, arch base, and side arch waists, combined with the automatic motor drive and automatic target recognition functions of the high-precision total station, high-frequency continuous monitoring of the tunnel structure's three-dimensional displacement (e.g., scanning once every 10 seconds) is achieved, providing high-precision, high-frequency data input for closed-loop control.

[0022] Furthermore, the electroosmotic electrode system includes anodes and cathodes arranged at intervals, and the electric field formed by the anodes and cathodes is used to achieve the electroosmotic drainage. Its beneficial effect is that by adopting an alternating arrangement of anodes and cathodes, the current field can be ensured to cover the area to be reinforced, allowing the electroosmotic drainage effect to be uniformly applied to the entire reinforced area, thereby improving the dissipation efficiency of excess pore water pressure.

[0023] Furthermore, during the grouting process, the control system dynamically adjusts the grouting parameters and electroosmosis parameters based on the real-time three-dimensional displacement data to maintain the tunnel deformation rate within a preset range. Its beneficial effect lies in the fact that by introducing an adaptive parameter adjustment strategy, the control system can dynamically adjust parameters such as grouting pressure, grouting rate, and electroosmosis voltage and current based on real-time monitored deformation data, ensuring that the grouting intensity and drainage efficiency match the real-time response of the strata, achieving smooth and stable deformation control.

[0024] Furthermore, the method also includes: when monitoring data shows that the tunnel deformation is stable within the target control range and shows no significant change within a preset observation period, the control system determines that the reinforcement is complete, gradually reduces the grouting intensity, and shuts down the electroosmotic electrode system. Its beneficial effect is that by setting a steady-state determination mechanism, when the tunnel deformation remains stable within a preset observation period (e.g., 72 hours), the system automatically determines that the reinforcement is complete and exits in an orderly manner, entering a dormant monitoring state, thus achieving fully automated management of the treatment process.

[0025] Furthermore, the bag grouting device is deployed in the soft soil stratum of the tunnel foundation; the electroosmotic electrode system is also deployed in the soft soil stratum of the tunnel foundation, and the anode and cathode areas of the electroosmotic electrode system cover the working area of ​​the bag grouting device. The beneficial effect is that by spatially matching the coverage area of ​​the electroosmotic electrode system with the working area of ​​the bag grouting device, it ensures that the excess pore water pressure generated during grouting can be timely and effectively covered and dissipated by the electroosmotic drainage effect, forming a spatial synergistic effect.

[0026] Furthermore, the method also includes: when monitoring data shows that the tunnel deformation is stable within the target control range and shows no significant change within a preset observation period, the control system determines that the reinforcement is complete, and controls the bag grouting device to gradually reduce the grouting intensity and controls the electroosmotic electrode system to shut down. Its beneficial effect is that this step, in conjunction with the aforementioned steady-state determination mechanism, achieves a smooth transition from active reinforcement to passive monitoring, avoiding rebound or disturbance that may be caused by sudden cessation of work, and ensuring the long-term stability of the reinforcement effect.

[0027] Compared with the prior art, the present invention has the following beneficial effects: First, at the level of control principle, this invention breaks through the traditional passive "open-loop" or "semi-open-loop" mode of grouting reinforcement that relies on manual experience and preset parameters, and constructs a dynamic closed-loop control system with tunnel deformation response as the core triggering basis. By directly using millisecond-level three-dimensional displacement data collected by a high-precision total station as the input variable of the control system, dynamic coupling between reinforcement grouting parameters and the real-time deformation state of the tunnel is achieved. This mechanism effectively overcomes the technical challenge of control commands lagging behind the actual response of the strata under the rheological characteristics of soft soil, ensuring the timeliness and accuracy of deformation control.

[0028] Secondly, at the level of mechanism of action, this invention innovatively utilizes the synergistic effect of bag expansion and electroosmotic drainage, solving the problem of excess pore water pressure accumulation caused by grouting in soft clay from the perspective of soil mechanics theory. By applying electroosmosis while the bag expands, the electric field force drives the directional migration of pore water, accelerating the dissipation of excess pore water pressure. This synergistic mechanism of "lifting and draining simultaneously" effectively inhibits the reconsolidation and settlement of the strata after grouting, ensuring the long-term stability of the tunnel structure.

[0029] Third, at the engineering implementation level, this invention significantly improves construction safety and reduces overall costs by introducing multi-level safety threshold criteria and an automatic pause protection strategy. The system can automatically identify conditions such as sudden changes in deformation rate or displacement approaching the limit, and immediately trigger the "stop grouting, enhance electroosmosis" protection action, effectively avoiding the risk of deformation exceeding limits. At the same time, this highly automated adaptive control method greatly reduces reliance on on-site technical personnel, lowers labor costs, and shortens the treatment cycle. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of 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, wherein: Figure 1 This is a schematic diagram of the overall flow of the control method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the tunnel deformation control range and safety threshold provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the control logic for soft soil reinforcement of tunnel foundation provided in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] This invention provides a method for precise control and reinforcement of soft soil deformation at the tunnel foundation, comprising: The system includes a monitoring unit, a bag grouting device, and an electroosmotic electrode system. The monitoring unit is used to collect three-dimensional displacement data of the tunnel, the bag grouting device is used to perform bag expansion grouting, and the electroosmotic electrode system is used to perform electroosmotic drainage. The control system acquires the tunnel's three-dimensional displacement data collected in real time by the monitoring unit; The control system dynamically compares the real-time three-dimensional displacement data with preset deformation control indicators. The deformation control indicators include a target control range and a deformation safety threshold. The target control range is the ideal adjustment range for tunnel uplift or settlement. The deformation safety threshold includes at least one of the maximum allowable uplift, the maximum allowable settlement, and the maximum deformation rate. When the real-time three-dimensional displacement data exceeds the target control range, the control system controls the bag grouting device to perform bag expansion grouting to lift the tunnel structure; During the sac expansion grouting, the control system controls the electroosmotic electrode system to perform electroosmotic drainage to accelerate the dissipation of excess pore water pressure generated during grouting; When the real-time three-dimensional displacement data reaches or approaches the deformation safety threshold, the control system executes a protection strategy, which includes suspending the bladder expansion grouting and maintaining or enhancing the electroosmotic drainage.

[0033] Specifically, the monitoring unit includes scanning prisms deployed in key deformation areas of the tunnel structure, and the real-time three-dimensional displacement data is acquired by continuously scanning the scanning prisms using a high-precision total station.

[0034] The electroosmotic electrode system includes anodes and cathodes arranged at intervals, and the electric field formed by the anodes and cathodes is used to achieve the electroosmotic drainage.

[0035] The control system dynamically adjusts the grouting parameters and electroosmosis parameters based on the real-time three-dimensional displacement data during the grouting of the bladder to maintain the tunnel deformation rate within a preset range.

[0036] The method also includes: when monitoring data shows that the tunnel deformation is stable within the target control range and there is no significant change within the preset observation period, the control system determines that the reinforcement is complete, gradually reduces the grouting intensity, and shuts down the electroosmotic electrode system.

[0037] The bag grouting device is installed in the soft soil layer of the tunnel foundation; the electroosmotic electrode system is installed in the soft soil layer of the tunnel foundation, and the arrangement area of ​​the anode and cathode of the electroosmotic electrode system covers the working area of ​​the bag grouting device.

[0038] The method also includes: when monitoring data shows that the tunnel deformation is stable within the target control range and there is no significant change within the preset observation period, the control system determines that the reinforcement is complete, and controls the bag grouting device to gradually reduce the grouting intensity and controls the electroosmotic electrode system to shut down.

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the following description will be provided in conjunction with the appendix. Figure 1 To be continued Figure 3 The present invention will be further described in detail with reference to specific embodiments. However, it should be understood that the specific embodiments of the present invention are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0040] Example 1 This invention provides a method for precise control and reinforcement of soft soil deformation at the tunnel foundation. This method achieves dynamic adjustment of the soft soil stratum reinforcement process by constructing a closed-loop control system with tunnel deformation response as the core.

[0041] I. Hardware Deployment Steps; First, perform the steps of "deploying monitoring units, grouting devices for bladders and electroosmosis electrode system" as described in claim 1.

[0042] like Figure 1 and Figure 3 As shown, high-precision total station scanning prisms are installed in key deformation areas of the tunnel segments, such as the arch crown, arch base, and both sides of the arch waist, as signal sources for deformation sensing. The spacing of the scanning prisms is determined according to the tunnel cross-section dimensions and deformation monitoring requirements, generally with one monitoring section every 5-10 meters, and four scanning prisms deployed in each section (arch crown, arch base, left arch waist, and right arch waist). By deploying scanning prisms as monitoring units, accurate measurement of the three-dimensional displacement of the tunnel structure is achieved, providing a high-precision data foundation for subsequent dynamic comparison. Targeted deployment in key deformation areas enables comprehensive capture of the deformation characteristics of the tunnel cross-section, avoiding monitoring blind spots.

[0043] Simultaneously, grouting pipes are inserted into the pre-reserved grouting holes in the tunnel. The grouting pipes are wrapped with carbon fiber cloth as electroosmotic electrodes, and emulsion capsule bags are installed at the ends of the pipes. The electroosmotic electrodes are arranged with alternating anodes and cathodes. The distance between the anodes and cathodes is determined based on the soil resistivity and the electric field coverage, generally 1-2 meters, to ensure that the current field covers the area to be reinforced. The depth to which the grouting pipe extends into the soft soil layer of the tunnel foundation is determined according to the required reinforcement depth, generally 3-5 meters below the tunnel floor. By deploying the capsule grouting device and the electroosmotic electrode system, a lifting execution unit and a drainage consolidation execution unit are established, laying the physical foundation for subsequent collaborative operations. The constraint effect of the capsules allows the grouting pressure to be precisely applied to the target area, avoiding the problem of disordered grout diffusion in traditional grouting.

[0044] A TS30 total station was installed inside the tunnel. This total station features automatic motor drive and automatic target recognition, enabling automatic identification and continuous tracking measurement of the scanning prism. The total station achieves a measurement accuracy of 0.1 mm, and the sampling frequency can be set to scan once every 10 seconds. The communication interface of the total station is connected to an industrial control computer (as the control system) via a data transmission line. The industrial control computer is pre-installed with the control software of this invention. Through the cooperation of the high-precision total station and the scanning prism, high-frequency, high-precision continuous monitoring of tunnel deformation is achieved, providing real-time and reliable data input for closed-loop control and realizing millisecond-level perception of tunnel deformation status.

[0045] II. System initialization and parameter setting steps; The control system is activated, and the total station performs an initial scan of each scanning prism to establish a three-dimensional coordinate reference for the tunnel cross-section. This reference serves as the initial state for subsequent deformation calculations.

[0046] Subsequently, local tunnel structure safety specifications and operating standards were input into the control software, and dual control indicators were set: (1) Target control range: The final allowable range of uplift or settlement of the tunnel is set. In this embodiment, according to the safety requirements of the tunnel structure, the target control range is set as an uplift of 2mm ± 0.5mm, that is, the final uplift of the tunnel should be controlled between 1.5mm and 2.5mm. By setting the target control range, a clear target guidance is provided for the reinforcement work, making the reinforcement process based on evidence, and realizing the transformation from "blind grouting" to "target-guided grouting".

[0047] (2) Deformation safety threshold: The maximum allowable single lift, the maximum allowable cumulative settlement, and the maximum deformation rate are set. In this embodiment, the maximum allowable single lift is set to 0.5 mm, the maximum allowable cumulative settlement is set to 3 mm, and the maximum deformation rate is set to 0.1 mm / min. By setting the deformation safety threshold, a safety boundary is defined. When the deformation approaches this boundary, the system automatically triggers a protection mechanism to effectively prevent the risk of deformation exceeding the limit and construct a multi-level safety control system.

[0048] III. Steps for initiating collaborative reinforcement operations; When the control system issues the "start lifting" command, the system automatically outputs a control signal to start the bag grouting pump, injecting grout into the formation in a preset low-pressure, slow-speed mode. The initial grouting pressure is set to 0.2 MPa, and the grouting rate is set to 0.5 L / min. After the grout is injected into the bag, the bag gradually expands, applying a uniform physical lifting force to the surrounding soil, causing the tunnel to achieve the target lifting response. By adopting the bag expansion grouting method, the problem of disordered grout diffusion in soft clay in traditional grouting is avoided, improving the accuracy and effectiveness of reinforcement. The controlled expansion of the bag allows the grouting pressure to be precisely applied to the target area, avoiding the risk of hydraulic fracturing.

[0049] Simultaneously, the system is powered on by the DC power supply of the electroosmotic electrode system, applying a DC electric field to the soft soil layer. The electroosmotic DC voltage is set to 30V, and the current density is set to 0.5A / m². Under the action of the electric field, cations in the pore water of the soil migrate towards the cathode, driving the pore water to migrate directionally towards the cathode (drainage end), forming an electroosmotic drainage effect. The electroosmotic effect begins to drive the pore water in the soil to migrate towards the drainage end, aiming to counteract the excess pore water pressure generated by grouting. By simultaneously initiating electroosmotic drainage during the expansion grouting of the slab, a coordinated operation mechanism of "lifting and draining simultaneously" is achieved, effectively suppressing the accumulation of excess pore water pressure generated by grouting and solving the problem of post-grouting consolidation settlement from the source.

[0050] It should be noted that the grouting pressure, grouting rate, electroosmosis voltage, and current density parameters mentioned above can be dynamically adjusted according to formation conditions and deformation response. Typically, the selectable range for grouting pressure is 0.1 MPa to 0.5 MPa, the selectable range for grouting rate is 0.3 L / min to 1.0 L / min, the selectable range for electroosmosis DC voltage is 20 V to 50 V, and the selectable range for current density is 0.3 A / m² to 0.8 A / m². Those skilled in the art can select and adjust these ranges according to actual working conditions.

[0051] During grouting and electroosmosis operations, the control system dynamically adjusts the grouting and electroosmosis parameters based on real-time three-dimensional displacement data. For example, when the deformation rate is below 0.05 mm / min, the control system appropriately increases the grouting pressure to 0.3 MPa and the grouting rate to 0.8 L / min; when the deformation rate approaches 0.1 mm / min, the control system reduces the grouting pressure to 0.1 MPa and the grouting rate to 0.3 L / min, while simultaneously increasing the electroosmosis DC voltage to 40 V to enhance drainage. This adaptive parameter adjustment strategy matches the grouting intensity and drainage efficiency with the real-time response of the formation, achieving smooth and stable deformation control and avoiding problems such as excessively rapid or slow uplift caused by inappropriate parameters.

[0052] IV. Real-time monitoring and closed-loop feedback steps; During the reinforcement process, the total station maintains a high frequency of continuous scanning (scanning once every 10 seconds) to calculate the settlement, uplift and convergence deformation of the tunnel cross section in real time, and feeds the data back to the industrial control computer in real time.

[0053] The control system dynamically compares real-time monitoring data with the deformation control indicators set in step two. Specifically, it compares the current uplift with the target control range (1.5mm-2.5mm) and the current deformation rate with the safety threshold (0.1mm / min). Through this real-time monitoring and dynamic comparison mechanism, millisecond-level perception and real-time judgment of tunnel deformation status are achieved, providing a decision-making basis for adaptive regulation and constructing a complete closed-loop control system of "monitoring—judgment—execution—feedback—adjustment".

[0054] V. Adaptive Risk Avoidance and State Adjustment Steps; If monitoring data shows that the tunnel deformation rate suddenly increases and reaches or approaches a safety threshold (e.g., the uplift rate reaches 0.08 mm / min, close to the threshold of 0.1 mm / min), the control system immediately triggers the "automatic risk avoidance" logic: (1) Immediate grouting stop: The system automatically cuts off the power supply to the grouting pump, stops the bag expansion grouting, and prevents the strata from splitting or the tunnel from being excessively uplifted. By pausing grouting, the soil squeezing effect is immediately blocked, the trend of further deformation is curbed, and the tunnel structure damage caused by excessive grouting pressure is effectively prevented.

[0055] (2) Enhanced electro-osmotic drainage: The system maintains or automatically increases the current parameters of the electro-osmotic system (e.g., increasing the current density from 0.5A / m² to 0.8A / m²), using electro-osmosis to accelerate the dissipation and discharge of excess pore water pressure accumulated in soft soil. By enhancing electro-osmotic drainage, the stratum can quickly return from a "stressed disturbance state" to a "consolidated and stable state", creating stable stratum conditions for subsequent precise grouting.

[0056] Once the deformation rate falls back to a safe range (e.g., below 0.05 mm / min) and the ground displacement stabilizes, the control system recalculates the required grouting volume based on the difference between the current elevation and the target elevation. It automatically restarts the grouting pump and adjusts the grouting parameters (e.g., reducing the grouting speed to 0.3 L / min) to continue the micro-volume, precise lifting operation. The system repeats the closed-loop process of "monitoring—judgment—pause / drainage—restart" until the tunnel elevation enters the target control range. By introducing an automatic risk avoidance strategy, the system effectively mitigates the risk of tunnel deformation exceeding limits that may be caused by human error or unattended operation at night, significantly improving construction safety and achieving all-weather, unmanned intelligent control.

[0057] VI. Steady-state determination and system hibernation steps; When monitoring data shows that the tunnel deformation has stabilized within the target control range (1.5mm-2.5mm) and there is no significant settlement or uplift trend within the preset observation period (72 hours) (i.e., the deformation change is less than 0.1mm), the control system determines that the reinforcement is complete.

[0058] At this point, the system gradually reduces the grouting intensity (grouting pressure decreases by 0.05 MPa every 30 minutes until it reaches zero) until it completely shuts down and shuts down the electroosmosis system. It then generates a construction log (including key parameters such as grouting volume, grouting pressure, electroosmosis voltage, and deformation data) and enters a low-power sleep monitoring state, retaining only periodic total station scanning (e.g., every 2 hours) for subsequent verification. By setting a steady-state determination mechanism, automatic shutdown and sleep monitoring after reinforcement completion are achieved, reducing manual intervention, improving the level of project automation, and laying the foundation for subsequent long-term operation and maintenance monitoring.

[0059] VII. Summary of Application Effects and Parameter Range; The method for precise control and reinforcement of soft soil deformation at the tunnel foundation, as described in this embodiment, was exemplarily tested in a subway tunnel foundation soft soil reinforcement project (the geological conditions of this project were typical soft clay with a water content of 45%-55% and a porosity of 1.2-1.5). Engineering practice shows that: (1) The accuracy of tunnel deformation control is significantly improved: Through real-time monitoring and dynamic control, the final uplift of the tunnel is controlled within the range of 2.0mm±0.3mm, which is far superior to the control accuracy of ±1.5mm of the traditional grouting method.

[0060] (2) Significantly reduced settlement after grouting: After applying the method of the present invention, the reconsolidation settlement within 72 hours after the end of grouting is only 0.2 mm, while the reconsolidation settlement of the traditional grouting method is usually 0.8-1.2 mm, and the settlement is reduced by more than 70%.

[0061] (3) Improved construction efficiency: Fully automatic closed-loop control reduces manual monitoring and operation time. A single shift can complete twice the amount of grouting work of traditional methods, and the treatment cycle is shortened by about 40%.

[0062] (4) Improved construction safety: The automatic risk avoidance strategy effectively prevented the risk of deformation exceeding the limit. No structural damage or safety accidents caused by deformation exceeding the limit occurred during the entire treatment process.

[0063] In summary, this invention achieves dynamic coupling between grouting parameters and real-time tunnel deformation by constructing a dynamic closed-loop control system with tunnel deformation response as the core triggering basis; effectively suppresses ground reconsolidation settlement after grouting through the synergistic effect of bag expansion and electroosmotic drainage; and significantly improves construction safety and reduces overall costs through multi-level safety threshold criteria and automatic pause protection strategy.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various improvements and modifications without departing from the spirit and principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for precise control and reinforcement of soft soil deformation at tunnel foundations, characterized in that, include: The system includes a monitoring unit, a bag grouting device, and an electroosmotic electrode system. The monitoring unit is used to collect three-dimensional displacement data of the tunnel, the bag grouting device is used to perform bag expansion grouting, and the electroosmotic electrode system is used to perform electroosmotic drainage. The control system acquires the tunnel's three-dimensional displacement data collected in real time by the monitoring unit; The control system dynamically compares the real-time three-dimensional displacement data with preset deformation control indicators. The deformation control indicators include a target control range and a deformation safety threshold. The target control range is the ideal adjustment range for tunnel uplift or settlement. The deformation safety threshold includes at least one of the maximum allowable uplift, the maximum allowable settlement, and the maximum deformation rate. When the real-time three-dimensional displacement data exceeds the target control range, the control system controls the bag grouting device to perform bag expansion grouting to lift the tunnel structure; During the sac expansion grouting, the control system controls the electroosmotic electrode system to perform electroosmotic drainage to accelerate the dissipation of excess pore water pressure generated during grouting; When the real-time three-dimensional displacement data reaches or approaches the deformation safety threshold, the control system executes a protection strategy, which includes suspending the bladder expansion grouting and maintaining or enhancing the electroosmotic drainage.

2. The method according to claim 1, characterized in that, The monitoring unit includes scanning prisms deployed in key deformation areas of the tunnel structure. The real-time three-dimensional displacement data is acquired by continuously scanning the scanning prisms using a high-precision total station.

3. The method according to claim 1, characterized in that, The electroosmotic electrode system includes anodes and cathodes arranged at intervals, and the electric field formed by the anodes and cathodes is used to achieve the electroosmotic drainage.

4. The method according to claim 1, characterized in that, The control system dynamically adjusts the grouting parameters and electroosmosis parameters based on the real-time three-dimensional displacement data during the grouting of the bladder to maintain the tunnel deformation rate within a preset range.

5. The method according to claim 1, characterized in that, Also includes: When monitoring data shows that the tunnel deformation is stable within the target control range and there is no significant change within the preset observation period, the control system determines that the reinforcement is complete, gradually reduces the grouting intensity, and shuts down the electroosmotic electrode system.

6. The method according to claim 1, characterized in that, The bag grouting device is installed in the soft soil layer of the tunnel foundation; the electroosmotic electrode system is installed in the soft soil layer of the tunnel foundation, and the arrangement area of ​​the anode and cathode of the electroosmotic electrode system covers the working area of ​​the bag grouting device.

7. The method according to claim 1, characterized in that, Also includes: When monitoring data shows that the tunnel deformation is stable within the target control range and does not change significantly within the preset observation period, the control system determines that the reinforcement is complete and controls the bag grouting device to gradually reduce the grouting intensity and controls the electroosmotic electrode system to shut down.

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