Shield tunneling near existing tunnel construction stratum pre-grouting device and grouting control method

Abstract

The application discloses a pre-grouting device for stratum construction near existing tunnels by a shield and a grouting control method, and relates to the field of grouting construction in tunnel construction. In order to solve the problem of lagging reflection and large deviation of a grouting system in the prior art. The device comprises a tunnel displacement sensing module, a grouting execution mechanism and a dynamic control system, and forms working steps of sensing, decision-making, execution and feedback. The device has the advantages that the real-time feedback of a tunnel displacement vector can be used to automatically trigger compensatory grouting of a corresponding region, the convergence speed of the tunnel displacement is improved, and the amount of invalid grouting is reduced.

Description

Technical Field

[0001] This invention discloses a pre-grouting device and grouting control method for shield tunneling near existing tunnel construction, which relates to the field of grouting construction in tunnel construction and is applicable to risk control when shield tunnels pass through existing tunnels at close range (net distance < 1D). Background Technology

[0002] In tunnel construction, grouting is a key technical means to control ground deformation and ensure the stability of the tunnel structure. With the widespread application of construction techniques such as shield tunneling and mining methods, the requirements for the precision of controlling displacements such as ground settlement, segment uplift, and tunnel convergence are becoming increasingly stringent. Especially when traversing sensitive areas such as existing structures, densely populated urban areas, and water-rich soft strata, the precise control of grouting parameters (including grouting pressure, grouting volume, and grouting timing) is directly related to construction safety and project quality.

[0003] In recent years, some tunnel boring machines and their supporting monitoring systems have achieved automatic recording and basic control of grouting parameters, and displacement monitoring has gradually shifted from manual measurement to automated online monitoring. However, due to factors such as system architecture and data transmission protocols, displacement monitoring systems and grouting control systems are mostly still operating independently, and the data between the two has not achieved real-time interaction and deep integration. This has led to the following significant shortcomings in the practical application of existing technologies: Main defects of existing technology 1. Independent System Operation and Significantly Delayed Data Feedback: Under current technological conditions, the displacement monitoring system (typically based on total stations, hydrostatic levels, or laser ranging) and the grouting control system (using frequency converters to control the grouting pumps) operate independently, lacking direct signal linkage between data acquisition and command execution. Displacement data often needs to be manually recorded or periodically uploaded to a remote server, and then manually adjusted by operators after assessment. This data feedback delay is typically more than 5 minutes, during which time ground deformation may have intensified, causing grouting measures to lag behind deformation development and preventing the achievement of closed-loop control for "real-time sensing and real-time adjustment."

[0004] 2. Grouting control relies solely on displacement amplitude, ignoring direction and spatial distribution characteristics: Currently, grouting parameter adjustments are mainly based on the amplitude changes at displacement monitoring points, focusing only on "how much deformation there is," without in-depth analysis of the displacement direction (upward / downward, leftward / rightward deviation) and its spatial distribution along the tunnel axis. In reality, the deformation direction of the tunnel at different construction stages has a clear mechanical orientation. For example, segment uplift requires adjustment of top grouting parameters, while surface settlement requires enhanced bottom or lateral grouting. This control model, ignoring displacement direction and distribution characteristics, easily leads to "blind" grouting: insufficient grouting in necessary areas and excessive grouting in unnecessary areas, resulting in grout waste, increased ground disturbance, and even inducing new safety problems.

[0005] 3. Lack of a quantitative mapping model between displacement and grouting parameters leads to a significant lag effect in compensatory grouting: Due to the lack of a quantitative mapping model based on engineering measurement data (such as the mathematical relationship between displacement rate and grouting pressure, and the correspondence rules between displacement direction and grouting point location), current grouting control relies heavily on empirical judgment. Especially when synchronous grouting is ineffective or grouting parameters need to be switched before and after cross-section changes, compensatory grouting often only passively initiates after displacement exceeds limits, forming a lag control chain of "deformation → detection → grouting → re-deformation." This ex-post compensation mode is not only inefficient but also makes it difficult to control the displacement within design requirements. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of severe data feedback lag and large grouting deviation in the prior art.

[0007] The specific solution of the present invention is: a pre-grouting device for shield tunneling near existing tunnel construction, comprising a tunnel displacement sensing module, a grouting actuator, and a dynamic control system; The tunnel displacement sensing module includes a three-dimensional fiber optic grating displacement sensor group installed on the inner wall of the tunnel and a ranging sensor corresponding to the laser pulse generation. The grouting actuator includes 8-16 radial grouting units with independent servo valves. The pressure regulation accuracy of the grouting unit is ±0.05MPa. The outlet of the grouting unit extends from inside the lining segment to outside the lining segment. The dynamic control system includes: a background system that establishes a fuzzy rule base for the mapping relationship between displacement and grouting volume, whose output parameters include: a. displacement direction weighting coefficient α, i.e. axial / radial displacement ratio; b. critical grouting intensity and Q. pressure gradient compensation value ΔP; the background system and the tunnel displacement sensing module transmit data via digital circuits, and the output of the background system controls the control components of the grouting actuator to control the grouting flow rate of each grouting unit.

[0008] In practice, among the 8-16 radial grouting units with independent servo valves, up to 12 radial grouting units are the main control components. The main control components are distributed in a 120-degree ring, forming a topological structure. The other radial grouting units are distributed in a motorized manner on the ring line and participate in the grouting work.

[0009] In specific implementation, it also includes auxiliary quick-setting grout pipelines. The quick-setting grout pipelines have independent grouting systems, grouting power sources and grouting pipes. They are connected to each grouting unit as branch pipelines to form real-time replacement.

[0010] In specific implementation, the three-dimensional fiber optic displacement sensor in the three-dimensional fiber optic displacement sensor group is installed between each grouting point, including 4 ranging sensors, each spaced 90 degrees apart.

[0011] In specific implementation, it also includes an auxiliary device for fixing the tunnel displacement sensing module. The auxiliary device includes a ring frame with rotational freedom and a bottom support below the ring frame. On the ring frame, a fixing fixture for at least 12 radial grouting units is slidably installed. A locking component is provided between the fixing fixture and the ring frame. Correspondingly, in the lining grouting hole group, at least 4 grouting holes are evenly distributed relative to the center, and spare grouting holes are reserved at the upper and lower 5-degree arc angles. The locking component includes an upper ring, a lower ring, and a fastening bolt that fixes the upper ring and the lower ring by threads.

[0012] In specific implementation, the annular frame includes two sets of annular pipes, with a slide rail between the annular pipes to secure the fixture. The bottom support includes a horizontal support and a longitudinal support. The bottom of the longitudinal support is equipped with rollers, and the horizontal support is equipped with a transmission mechanism that drives the two sets of annular pipes to rotate synchronously. A sliding pair is provided between the two sets of annular pipes and the horizontal support. A positioning fixture for the outlet pipe of quick-setting grout is also slidably installed on the outer ring of one side of the annular frame. An independent outlet pipe of quick-setting grout is slidably installed on each outlet pipe positioning fixture. Radial grouting units are installed inside the two sets of annular pipes of the annular frame.

[0013] In practice, an auxiliary pull rope is wound around the fixed fixture to simulate the chord length between adjacent fixed fixtures in the tunnel.

[0014] In specific implementation, a grouting control method is also involved, which uses the aforementioned shield tunneling pre-grouting device for adjacent existing tunnel construction, and includes the following steps: (1) Sensing: The 40-meter risk section is covered by a distribution pattern of 8 groups of 5 meters each. Three groups of fiber optic grating displacement sensors are arranged circumferentially on the inner wall of the existing tunnel to form sensing data group A. Laser pulses are emitted to scan the surface of the tunnel lining. The three-dimensional deformation is calculated by the grating wavelength offset to form sensing data group B. Temperature sensing devices are installed on the inner lining of the tunnel or on the trolley. After combining the data of group A and group B to form fused data, the environmental temperature drift is corrected in real time by the data of the temperature sensing device with the participation of the temperature compensation module. The deformation vector field containing displacement, direction angle θ and rate of change v is output. (2) Decision: Inner loop (flow rate): Receives the flow rate setpoint and modulates the servo valve opening with PWM (200ms level response); Outer loop (pressure): Compares the set pressure with the actual pressure and dynamically adjusts the inner loop input (steady-state error ≤ 0.02MPa). (3) Execution: Upon receiving the control command, the servo valve precisely adjusts the slurry flow rate according to the PWM duty cycle, and the pressure sensor transmits data back to the PID controller in real time to form a closed loop; when the displacement difference in the same section is >15%, the high-pressure side unit automatically increases the pressure to 1.5 times; when reverse displacement is detected, it automatically switches to the dedicated pipeline; (4) Feedback: After step (3), the measurement is restarted in the manner of step (1) to form the adjusted data. The adjusted data is compared with the initial data in step (1) to form a closed loop feedback.

[0015] In practice, the operation includes a working mode and an emergency mode. In the working mode, each servo valve controls the slurry flow rate in a balanced manner. When the displacement difference at the same cross section is greater than 15%, the emergency mode is activated, that is, the high-pressure side unit automatically increases the pressure to 1.5 times, and at the same time, the adjacent fast-setting slurry branch is opened to achieve rapid slurry setting. Furthermore, when reverse displacement is detected, each operation is reversed. The beneficial effects of this invention are as follows: Based on real-time feedback of the tunnel displacement vector (displacement > 2mm or rate of change > 0.5mm / h), it can automatically trigger compensatory grouting in the corresponding area, thereby increasing the tunnel displacement convergence speed by more than 40% and reducing the amount of ineffective grouting by 25-35%. By acquiring real-time three-dimensional deformation data of the tunnel through an embedded displacement sensing network and combining it with a dynamic control algorithm for grouting parameters, spatially differentiated output of grouting pressure and flow rate can be achieved. It has targeted adjustment modes for various working conditions, and the overall adjustment response speed is fast and the adjustment is sensitive; The grouting pipes or quick-setting grout pipes involved in this application are installed with a set of structural installation equipment. This installation equipment has a high degree of freedom and can be flexibly adjusted during construction. At the same time, it can ensure the installation accuracy of the equipment and facilitate adjustment and maintenance in the later stage, thereby improving the overall operation effect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the sensor device distribution in this invention; Figure 2 This is a perspective view of the auxiliary support structure in this invention; Figure 3 yes Figure 2 The main view of the structure; Figure 4 yes Figure 2 Left view of the middle structure; Figure 5 yes Figure 3 Sectional view of plane AA in the middle; Figure 6 yes Figure 5 BB section view in the middle; Figure 7 This is a perspective view of the auxiliary support structure in this invention from another angle; In the attached diagram: 1. Lining; 2. Ring pipe; 3. Fixture; 4. Motor; 5. Longitudinal support; 6. Roller; 7. Horizontal support; 8. Groove for limiting the moving pair; 9. Level; 10. Upper ring; 11. Lower ring; 12. Grouting point; 13. Distance sensor; 14. Three-dimensional fiber optic displacement sensor; 15. Fastening bolt. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] The shield tunneling pre-grouting device for the ground stratum in close proximity to existing tunnel construction includes a tunnel displacement sensing module, a grouting actuator, and a dynamic control system. The tunnel displacement sensing module includes a three-dimensional fiber optic grating displacement sensor group installed on the inner wall of the tunnel and a ranging sensor 13 corresponding to the laser pulse generation. The grouting actuator includes 8-16 radial grouting units with independent servo valves. The pressure regulation accuracy of the grouting unit is ±0.05MPa. The outlet of the grouting unit extends from inside the segment to outside the lining segment 1. The dynamic control system includes: a background system that establishes a fuzzy rule base for the mapping relationship between displacement and grouting volume, whose output parameters include: a. displacement direction weighting coefficient α, i.e. axial / radial displacement ratio; b. critical grouting intensity and Q. pressure gradient compensation value ΔP; the background system and the tunnel displacement sensing module transmit data via digital circuits, and the output of the background system controls the control components of the grouting actuator to control the grouting flow rate of each grouting unit.

[0019] Of the 8-16 radial grouting units with independent servo valves, 12 are the main control components, which are arranged in a 120-degree ring to form a topological structure. The other 4 radial grouting units are distributed in a motorized manner along the ring line, participating in the grouting work. When the passage of a grouting unit is blocked or damaged, it can immediately serve as a replacement to complete the work.

[0020] It also includes auxiliary quick-setting grout pipelines, which have independent grouting systems, grouting power sources, and grouting pipes. These pipelines are connected to each grouting unit as branch lines to allow for real-time, opportunistic replacement. The attached diagram does not show the auxiliary quick-setting grout pipelines fixed to the ring frame; in actual work, they are primarily installed on-site. Their main function is to handle emergency situations.

[0021] The three-dimensional fiber optic displacement sensor 14 in the three-dimensional fiber optic displacement sensor group is installed between each grouting point 12, including 4 ranging sensors 13, each spaced 90 degrees apart.

[0022] In this embodiment, an auxiliary device for fixing the tunnel displacement sensing module is also included. The auxiliary device includes a ring-shaped frame with rotational degrees of freedom and a bottom support below the ring-shaped frame. At least 12 radial grouting units of the fixing fixture 3 are slidably installed on the ring-shaped frame. A locking component is provided between the fixing fixture 3 and the ring-shaped frame. Correspondingly, in the grouting hole group of the lining 1, at least 4 grouting holes are evenly distributed relative to the center, with spare grouting holes reserved at 5-degree arc angles above and below them. The locking component includes an upper ring 10, a lower ring 11, and a fastening bolt 15 that secures the upper ring 10 and lower ring 11 via threads. During operation, the fixing fixture 3 is engaged between two sets of ring-shaped pipes 2, and then bolted together to achieve self-locking after the fixture is in place, achieving precise and rapid fixture placement. The ring frame's structural design allows it to swing at an angle greater than the angle between the fixed fixtures 3. This design ensures that there are no dead angles in the installation of the grouting pipe. Specifically, the ring frame has grooves, and a motor 4 is installed on the corresponding bottom support. The ring frame has a transmission structure that works with the motor 4. The output of the motor 4 drives the transmission structure, which in turn drives the ring frame to rotate. During the rotation, the grooves and the corresponding pins create a degree of freedom constraint.

[0023] The annular frame includes two sets of annular pipes 2, with a slide rail between the annular pipes 2 for mounting and fixing the fixture 3. The bottom support includes a horizontal support 7 and a longitudinal support 4. The longitudinal support 4 has rollers 6 at its bottom. Above the horizontal support 7 is a transmission mechanism that drives the two sets of annular pipes 2 to rotate synchronously. A sliding pair is provided between the two sets of annular pipes 2 and the horizontal support 7. A positioning fixture for the outlet pipe of quick-setting grout is also slidably installed on the outer ring of one side of the annular frame. An independent outlet pipe of quick-setting grout is slidably installed on each outlet pipe positioning fixture. Radial grouting units are installed inside the two sets of annular pipes 2 of the annular frame. During operation, after the annular frame moves to the corresponding position, the grouting pipe is installed on the fixing fixture 3.

[0024] An auxiliary pull rope is wound around the fixed fixture 3 to simulate the chord length between adjacent fixed fixtures 3 inside the tunnel. By fixing the chord length, the distance between the fixed fixtures 3 is assisted in fixing the distance between them.

[0025] The horizontal support 7 is equipped with a level 9, which can ensure the monitoring of the overall levelness of the equipment, and ensure the installation of precision equipment and the accurate installation of grouting equipment in the later stage.

[0026] It also relates to a grouting control method, using a pre-grouting device for tunneling near existing tunnel strata, comprising the following steps: (1) Sensing: The 40-meter risk section is covered by a distribution pattern of 8 groups of 5 meters each. Three groups of fiber optic grating displacement sensors are arranged circumferentially on the inner wall of the existing tunnel to form sensing data group A. Laser pulses are emitted to scan the surface of the tunnel lining 1. The three-dimensional deformation is calculated by the grating wavelength offset to form sensing data group B. Temperature sensing devices are installed on the inner lining 1 of the tunnel or on the trolley. After combining the data of group A and group B to form fused data, the environmental temperature drift is corrected in real time by the data of the temperature sensing device with the participation of the temperature compensation module. The deformation vector field containing displacement, direction angle θ and rate of change v is output. (2) Decision: Inner loop (flow rate): Receives the flow rate setpoint and modulates the servo valve opening with PWM (200ms level response); Outer loop (pressure): Compares the set pressure with the actual pressure and dynamically adjusts the inner loop input (steady-state error ≤ 0.02MPa). (3) Execution: Upon receiving the control command, the servo valve precisely adjusts the slurry flow rate according to the PWM duty cycle, and the pressure sensor transmits data back to the PID controller in real time to form a closed loop; when the displacement difference in the same section is >15%, the high-pressure side unit automatically increases the pressure to 1.5 times; when reverse displacement is detected, it automatically switches to the dedicated pipeline; (4) Feedback: After step (3), the measurement is restarted in the manner of step (1) to form the adjusted data. The adjusted data is compared with the initial data in step (1) to form a closed loop feedback.

[0027] In practice, the operation includes a working mode and an emergency mode. In the working mode, each servo valve controls the slurry flow rate in a balanced manner. When the displacement difference at the same cross section is greater than 15%, the emergency mode is activated, that is, the high-pressure side unit automatically increases the pressure to 1.5 times, and at the same time, the adjacent fast-setting slurry branch is opened to achieve rapid slurry setting. Furthermore, when reverse displacement is detected, each operation is reversed.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pre-grouting device for shield tunneling near existing tunnel construction, characterized in that: It includes a tunnel displacement sensing module, a grouting actuator, and a dynamic control system; The tunnel displacement sensing module includes a three-dimensional fiber optic grating displacement sensor group installed on the inner wall of the tunnel and a ranging sensor (13) corresponding to the laser pulse formation. The grouting actuator includes 8-16 radial grouting units with independent servo valves. The pressure regulation accuracy of the grouting unit is ±0.05MPa. The outlet of the grouting unit extends from inside the pipe segment to outside the lining (1) pipe segment. The dynamic control system includes: a background system that establishes a fuzzy rule base for the mapping relationship between displacement and grouting volume, whose output parameters include: a. displacement direction weighting coefficient α, i.e. axial / radial displacement ratio; b. critical grouting intensity and Q. pressure gradient compensation value ΔP; the background system and the tunnel displacement sensing module transmit data via digital circuits, and the output of the background system controls the control components of the grouting actuator to control the grouting flow rate of each grouting unit.

2. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 1, characterized in that: Of the 8-16 radial grouting units with independent servo valves, up to 12 radial grouting units are the main control components. The main control components are distributed in a 120-degree ring, forming a topological structure. The other radial grouting units are distributed in a motorized manner on the ring line and participate in the grouting work.

3. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 1, characterized in that: It also includes auxiliary quick-setting grout pipelines, which have independent grouting systems, grouting power sources and grouting pipes, and are connected to each grouting unit as branch pipelines to form real-time, opportunistic replacement.

4. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 1, characterized in that: The three-dimensional fiber grating displacement sensor (14) in the three-dimensional fiber grating displacement sensor group is installed between each grouting point (12), including 4 distance sensors (13), with a 90-degree angle between each.

5. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 1, characterized in that: It also includes an auxiliary device for fixing the tunnel displacement sensing module. The auxiliary device includes a ring frame with rotational freedom and a bottom support below the ring frame. On the ring frame, a fixing fixture (3) with at least 12 radial grouting units is slidably installed. A locking component is provided between the fixing fixture (3) and the ring frame. Correspondingly, in the grouting hole group of the lining (1), at least 4 grouting holes are evenly distributed relative to the center, and spare grouting holes are reserved at the upper and lower 5-degree arc angles. The locking component includes an upper ring (10), a lower ring (11), and a fastening bolt (15) that fixes the upper ring (10) and the lower ring (11) by thread.

6. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 5, characterized in that: The ring frame includes two sets of ring pipes (2), and a slide rail is formed between the ring pipes (2) to be used to fix the fixture (3). The bottom support includes a horizontal support (7) and a longitudinal support (4). The bottom of the longitudinal support (4) is provided with a roller (6). The horizontal support (7) is provided with a transmission mechanism that drives the two sets of ring pipes (2) to rotate synchronously. A sliding pair is provided between the two sets of ring pipes (2) and the horizontal support (7). A quick-setting grout outlet pipe positioning fixture is also slidably installed on the outer ring of one side of the ring frame. An independent quick-setting grout outlet pipe is slidably installed on each outlet pipe positioning fixture. A radial grouting unit is installed inside the two sets of ring pipes (2) of the ring frame.

7. The pre-grouting device for shield tunneling near existing tunnel construction as described in claim 6, characterized in that: An auxiliary pull rope is wound around the fixed fixture (3) to simulate the chord length between adjacent fixed fixtures (3) in the tunnel.

8. A grouting control method, using the pre-grouting device for shield tunneling near existing tunnel construction as described in claim 1, characterized in that, Includes the following steps: (1) Sensing: The 40-meter risk section is covered by a distribution pattern of 8 groups of 5 meters each. Three fiber optic grating displacement sensor groups are arranged circumferentially on the inner wall of the existing tunnel to form sensing data group A. Laser pulses are emitted to scan the surface of the tunnel lining (1). The three-dimensional deformation is calculated by the grating wavelength offset to form sensing data group B. Temperature sensing devices are installed on the inner lining (1) of the tunnel or on the trolley. After combining the data of group A and group B to form fused data, the environmental temperature drift is corrected in real time by the data of the temperature sensing device with the participation of the temperature compensation module. The deformation vector field containing displacement, direction angle θ and rate of change v is output. (2) Decision: Inner loop (flow rate): Receives the flow rate setpoint and modulates the servo valve opening with PWM (200ms level response); Outer loop (pressure): Compares the set pressure with the actual pressure and dynamically adjusts the inner loop input (steady-state error ≤ 0.02MPa). (3) Execution: Upon receiving the control command, the servo valve precisely adjusts the slurry flow rate according to the PWM duty cycle, and the pressure sensor transmits data back to the PID controller in real time to form a closed loop; when the displacement difference in the same section is >15%, the high-pressure side unit automatically increases the pressure to 1.5 times; when reverse displacement is detected, it automatically switches to the dedicated pipeline; (4) Feedback: After step (3), the measurement is restarted in the manner of step (1) to form the adjusted data. The adjusted data is compared with the initial data in step (1) to form a closed loop feedback.

9. The grouting control method as described in claim 8, characterized in that: The system includes a working mode and an emergency mode. In the working mode, each servo valve controls the slurry flow rate evenly. When the displacement difference between the same cross sections is greater than 15%, the emergency mode is activated, that is, the high-pressure side unit automatically increases the pressure to 1.5 times, and at the same time opens the adjacent fast-setting slurry branch to achieve rapid slurry setting. Furthermore, when reverse displacement is detected, each operation is reversed.

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