Shield small-radius curve secant active hinge launching and tunneling construction method and system

Abstract

The invention relates to a shield minor radius curve secant active hinge launching and tunneling construction method and system. The method comprises the steps that S1, trajectory planning is conducted; a secant method is adopted for track planning, the design curve is decomposed into multiple continuous secant lines meeting the deviation requirement, and a shield tunneling preset track meeting the preset deviation requirement is formed; s2, starting preparation is carried out; s3, calibrating the equipment; s4, starting a secant line; enabling the posture of the shield tunneling machine to dynamically follow the preset track by adjusting the stroke of a hinged oil cylinder in real time; s5, cutting line tunneling; in the tunneling process along the preset track, the stroke difference of the hinged oil cylinders is set in a feed-forward mode, so that the shield tunneling machine forms a pre-bending posture; the method comprises the following steps of S1, performing dynamic following and pre-bending by combining the steps S4 and S5 and utilizing an active hinge system through secant method trajectory planning in the step S1, so that the shield tunneling machine can actively and smoothly adapt to curve change, meanwhile, the posture can be flexibly adjusted according to the actual tunneling condition, the axis deviation caused by too small curve radius is reduced, and the tunneling precision is improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically to a method and system for initiating and tunneling a TBM using active articulation of a small-radius curve secant. Background Technology

[0002] In the construction of shield tunnels for urban subways, the shield launching shaft and tunnel route are often designed on small-radius curves due to constraints imposed by existing buildings, underground pipelines, and site layout. When the horizontal curve radius of the tunnel section is smaller than that of the launching shaft, traditional shield launching and tunneling methods face severe challenges. While the conventional tangential launching method ensures that the shield machine's axis is perpendicular to the tunnel portal at launch, during subsequent small-radius curve tunneling, the shield machine's long, straight, rigid body has poor turning flexibility, causing the cutterhead center to gradually deviate from the design axis. This leads to a series of problems, including over-excavation, increased friction between the shield and the soil, difficulties in segment assembly, and increased difficulty in controlling surface settlement. Especially in complex and sensitive environments requiring close proximity to important municipal pipelines, bridge foundations, or rivers, the precision requirements for controlling the tunneling trajectory are extremely high, and traditional methods struggle to meet millimeter-level deviation control requirements.

[0003] Currently, although there are engineering practices that use the "secant method" to replace the "tangent method" to alleviate the difficulty of curved tunneling, these practices largely rely on construction experience and lack systematic theoretical calculation models and precise quantitative control standards. Particularly concerning are how to scientifically determine secant parameters to ensure fitting accuracy, how to transform theoretical secant coordinates into on-site executable measurement benchmarks, and how to deeply integrate with the advanced active articulation system of the tunnel boring machine to achieve closed-loop control from static pre-setting to dynamic tracking.

[0004] Therefore, there is an urgent need to provide a method and system for the active articulation of shield tunneling at small-radius curves for initiation and excavation, in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and defects of the prior art and provide a method and system for the active articulation of shield tunneling initiation and tunneling construction on small-radius curves. This allows the shield machine to actively and smoothly adapt to curve changes, while flexibly adjusting its posture according to the actual tunneling situation, reducing axial deviation caused by excessively small curve radii, and improving tunneling accuracy.

[0006] The objective of this invention is achieved through the following technical solution: A method for active articulation of shield tunneling along a small-radius curve secant for launching and tunneling construction, applicable to shield tunneling projects where both the launching shaft and the tunnel section are located on a small-radius curve segment, and the horizontal curve radius of the section is smaller than the horizontal curve radius of the launching shaft, characterized by the following steps: S1: Trajectory planning; The secant method is used for trajectory planning, which decomposes the design curve into multiple continuous secants that meet the deviation requirements, forming a preset shield tunneling trajectory that meets the preset deviation requirements. S2: Launch preparation; Based on the starting section direction of the preset trajectory, install and precisely position the launching bracket in the launching well; install the reaction frame perpendicular to the starting section's propulsion direction; S3: Equipment calibration; Assemble a tunnel boring machine with active articulation function on the launching bracket, and perform initial attitude zero-position calibration on the tunnel boring machine to establish the transformation relationship between the machine coordinate system and the construction coordinate system; S4: Cut-line initiation; the tunnel boring machine (TBM) begins to excavate along the preset trajectory; when the front of the TBM enters the portal soil, the active articulation system is activated, and the stroke of the articulation cylinder is adjusted in real time to make the TBM's posture dynamically follow the preset trajectory; S5: Securing tunneling; During the tunneling process along the preset trajectory, the stroke difference of the articulated cylinder is set in a feedforward manner to make the tunnel boring machine (TBM) form a pre-bending posture; At the same time, the thrust of the propulsion jack is adjusted to control the angle of the TBM, so that it can advance smoothly along the preset trajectory.

[0007] Optionally, in step S1, the formula for calculating the initial attitude of the shield tunneling machine along the secant line of the small-radius curve segment is:

[0008]

[0009]

[0010] Where L is the secant length, α is the pre-angle, β is the angle corresponding to the secant, d is the offset between the design curve and the secant, and R is the radius of the design curve. The formula for calculating the maximum length of a secant is:

[0011] d max For the maximum allowable offset, L max This represents the maximum length of a single secant segment.

[0012] Optionally, the offset d between the design curve and the secant line shall not exceed ±50mm.

[0013] Optionally, in step S1, the formula for calculating the coordinates of the i-th secant segment is:

[0014] Where Yi is the ordinate of any point on the i-th secant line; Xi is the abscissa of any point on the i-th secant line; yi is the ordinate of the starting point of the i-th secant line; xi is the abscissa of the starting point of the i-th secant line; yi-j is the ordinate of the intersection point of the i-th secant line and the adjacent j-th secant line; xi-j is the abscissa of the intersection point of the i-th secant line and the adjacent j-th secant line; bi is the intercept. The formula for calculating the coordinates of the j-th secant segment is:

[0015] Where Yj is the ordinate of any point on the j-th secant line; Xj is the abscissa of any point on the j-th secant line; yi-j is the ordinate of the intersection point of the i-th secant line and the adjacent j-th secant line; xi-j is the abscissa of the intersection point of the i-th secant line and the adjacent j-th secant line; yj is the ordinate of the endpoint of the j-th secant line; xj is the abscissa of the endpoint of the j-th secant line; and bj is the intercept. The coordinates of each secant segment are calculated using the formulas for calculating the coordinates of the i-th and j-th secant segments mentioned above.

[0016] Optionally, in step S2, before installing the launching bracket in the launching shaft, the launching guide rail needs to be positioned and measured. The position of the tunnel centerline and the guide rail is laid out through the launching side control point, and the tunnel elevation control line and guide rail slope are measured by leveling method.

[0017] Optionally, the positioning error of the tunnel centerline, elevation control line, and guide rail slope shall not exceed 10mm; when installing the reaction frame, ensure that its force-bearing plane is perpendicular to the pre-set secant advance direction of the shield tunneling machine.

[0018] Optionally, in step S3, the equipment calibration step specifically involves: setting at least 8 forced centering prisms as zero-position markers on the stable structure of the tunnel boring machine, measuring the coordinates of the zero-position markers using the three-dimensional coordinate method, with a measurement error ≤ ±6mm; and establishing a conversion model based on the coordinates of the zero-position markers, the geometric coordinates of the tunnel boring machine cut center, and the shield tail center.

[0019] Optionally, in step S4, after the shield and articulated section of the tunnel boring machine enter the soil at the tunnel entrance and the active articulation system is activated, the real-time attitude of the tunnel boring machine displayed by the guidance system is compared in real time with the preset initial secant trajectory in the trajectory planning step; based on the attitude deviation data generated by the real-time comparison, the stroke of the hydraulic cylinder of the active articulation system is dynamically adjusted to continuously and slightly correct the tunnel boring machine's excavation direction, ensuring that it starts smoothly along the preset initial secant trajectory and transitions to the subsequent secant segment.

[0020] Optionally, in step S5, the stroke difference of the articulated cylinder is set in a feedforward manner as follows: based on the curvature change of the preset trajectory, the target stroke difference of the articulated cylinder required to generate a deflection angle between the middle shield and the front shield of the tunnel boring machine is calculated in advance.

[0021] A system for active articulation initiation and tunneling construction of shield tunnels with small radius curves includes: The trajectory planning module is used to execute the trajectory planning steps and generate a preset trajectory containing the coordinates of continuous secant segments; The measurement and positioning module is used to perform the measurements in the initial preparation step S2; The active articulated tunnel boring machine is installed on a precisely positioned launching guide rail and has completed zero-position calibration. The guidance and control system, integrated on the active articulated tunnel boring machine, is used to execute the secant initiation step S4 and the secant tunneling step S5. It includes: a real-time guidance unit for acquiring the real-time attitude of the tunnel boring machine; an articulation control unit for receiving real-time attitude data and preset trajectories, calculating and outputting articulation cylinder stroke adjustment commands; and a propulsion coordination unit for adjusting the zoned thrust of the propulsion jacks according to the tunneling stage and attitude requirements, working in coordination with the articulation control unit.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention includes S1: trajectory planning, which uses the secant method to plan the tunneling path trajectory, decomposing the complex design curve into continuous, multi-segment secants that meet the deviation requirements, and generating a preset trajectory that can be recognized and followed by the tunnel boring machine's automatic guidance system based on the above requirements; S2: launch preparation, which involves installing and precisely positioning the launch bracket on the bottom plate of the launch shaft according to the three-dimensional spatial orientation of the initial segment secant, followed by the installation of the reaction frame. S3: Equipment Calibration; On the positioned launching bracket, the active articulated shield machine host and its supporting equipment are hoisted and assembled. After assembly, the initial attitude zero position is calibrated, and a mathematical relationship is established with the geodetic construction coordinate system. S4: Securing Launch; The shield machine advances along the trajectory (initial secant line) preset in S1. When the shield machine's front shield and articulated part enter the tunnel portal soil, the active articulation system is immediately activated. The system continuously compares the shield machine's current position and attitude, measured in real time by the guidance system, with the preset initial secant line trajectory, calculates minor attitude deviations, dynamically adjusts the stroke of the articulation cylinders, and continuously and slightly corrects the direction of the shield machine's head so that it can follow the preset secant line launching trajectory. S5: Secant Excavation; When the tunnel boring machine (TBM) fully enters the soil and excavates along the subsequent secant, the system will pre-bend the machine before reaching the turning point based on the direction of the next secant segment to be reached, actively guiding the machine to turn. Through the secant trajectory planning in step S1, combined with the active articulation system in steps S4 and S5 for dynamic following and pre-bending, the TBM can actively and smoothly adapt to curve changes. At the same time, it can flexibly adjust its posture according to the actual excavation situation, reduce the axis deviation caused by the small curve radius, and improve the excavation accuracy. Attached Figure Description

[0023] Figure 1 This is a flowchart of the shield tunneling initiation and excavation construction process of the present invention.

[0024] Figure 2 This is a schematic diagram of the trajectory planning for the shield tunneling cut-line initiation in this invention.

[0025] Figure 3 This is a schematic diagram illustrating the calculation of the initial attitude of the shield tunneling machine using the secant line of a small-radius curve segment in this invention.

[0026] Figure 4 This is a schematic diagram of the secant coordinate calculation in this invention.

[0027] Figure 5 This is a schematic diagram of the active hinged connection structure in this invention. Detailed Implementation The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0028] This invention proposes a method and system for active articulation of shield tunneling on small-radius curves during launching and excavation. It is applicable to shield tunneling projects where both the launching shaft and the tunnel section are located on small-radius curves, and the horizontal curve radius of the section is smaller than the horizontal curve radius of the launching shaft. The method includes the following steps: S1: Trajectory planning; The secant method is used for trajectory planning, which decomposes the design curve into multiple continuous secants that meet the deviation requirements, forming a preset shield tunneling trajectory that meets the preset deviation requirements. S2: Launch preparation; Based on the starting section direction of the preset trajectory, install and precisely position the launching bracket in the launching well; install the reaction frame perpendicular to the starting section's propulsion direction; S3: Equipment calibration; Assemble a tunnel boring machine with active articulation function on the starting base, and perform initial attitude zero-position calibration on the tunnel boring machine to establish the transformation relationship between the machine coordinate system and the construction coordinate system; S4: Cut-line initiation; the tunnel boring machine (TBM) begins to excavate along the preset trajectory; when the front of the TBM enters the portal soil, the active articulation system is activated, and the stroke of the articulation cylinder is adjusted in real time to make the TBM's posture dynamically follow the preset trajectory; S5: Securing tunneling; During the tunneling process along the preset trajectory, the stroke difference of the articulated cylinder is set in a feedforward manner to make the tunnel boring machine (TBM) form a pre-bending posture; At the same time, the thrust of the propulsion jack is adjusted to control the angle of the TBM, so that it can advance smoothly along the preset trajectory.

[0029] Reference Figures 1 to 5In this embodiment, it is applied to shield tunneling projects where both the launching shaft and the tunnel section are smaller than the small-radius curve segment, and the horizontal curve radius of the section is smaller than the horizontal curve radius of the launching shaft. Since the shield machine launches on the curve and needs to directly enter the curved section, the shield machine's attitude changes significantly. The conventional tangent method cannot complete the launching and tunneling of the shield machine. Therefore, for this situation, a secant method combined with active articulation technology is used for launching and tunneling. The specific steps are as follows: S1: Trajectory planning. For the above curve conditions, the tangent method cannot meet the requirements. The secant method is used to plan the trajectory of the tunneling path. The complex design curve is decomposed into continuous, multi-segment secants that meet the deviation requirements. The maximum deviation between these secants and the original design curve must not exceed the preset allowable deviation value. Based on the above requirements, a preset trajectory is generated that can be recognized and followed by the shield machine's automatic guidance system.

[0030] S2: Launch preparation; Based on the three-dimensional spatial orientation of the preset trajectory generated in S1, the launch bracket is installed and precisely positioned on the bottom plate of the launch shaft. Then, the reaction frame is installed. When the reaction frame is installed, it provides a pressure-bearing plane for the shield tunneling reaction force and maintains a perpendicular relationship with the advancement direction of the starting segment secant to ensure the transmission of the launch thrust.

[0031] S3: Equipment calibration; On the positioned launching bracket, complete the hoisting and assembly of the active articulated shield machine main unit and its supporting equipment. After assembly, perform initial attitude zero-position calibration and establish a mathematical relationship with the earth construction coordinate system. Input this relationship into the shield machine's automatic guidance system to establish a coordinate transformation model between the two.

[0032] S4: Cutting line start; After the tunnel portal is sealed and breached, the tunnel boring machine (TBM) advances along the trajectory (starting cut line) preset in S1. When the front shield and articulated part of the TBM enter the soil of the tunnel portal, the active articulation system is immediately activated. The system continuously compares the current position and attitude of the TBM measured in real time by the guidance system with the preset starting cut line trajectory, calculates the slight attitude deviation, dynamically adjusts the stroke of the articulation cylinder, and makes continuous and slight corrections to the direction of the TBM head, so that it can follow the preset starting cut line trajectory through adjustment.

[0033] S5: Securing the tunnel boring machine (TBM) fully enters the soil and excavates along the subsequent secant line. The system pre-calculates and sets the stroke difference between the two ends of the articulated cylinders based on the direction of the next secant line to be reached, ensuring that the middle and front shields of the TBM form a pre-bending angle before reaching the turning point, actively guiding the machine's direction. Simultaneously, the system adjusts the thrust of each set of propulsion jacks around the TBM, along with the guiding force generated by the active articulation, to achieve precise and smooth control of the TBM's angle, ensuring that it smoothly turns and advances along the preset continuous broken line trajectory, avoiding sharp turns or jamming. Through the secant trajectory planning in step S1, combined with the dynamic following and pre-bending using the active articulation system in steps S4 and S5, the TBM can actively and smoothly adapt to curve changes. At the same time, it can flexibly adjust its posture according to the actual excavation situation, reducing the axis deviation caused by the small curve radius and improving the excavation accuracy.

[0034] Optionally, in this embodiment, the specific computational model required for secant trajectory planning in step S1 is referred to... Figure 2 and Figure 3 The model defines the geometric relationship between a single secant segment (length L) and the corresponding design arc (radius R). The formula for calculating the initial attitude of the shield tunneling machine's small-radius curve segment secant is as follows:

[0035]

[0036] Where L is the secant length, α is the pre-deflection angle, β is the angle corresponding to the secant, d is the offset between the design curve and the secant, and R is the radius of the design curve; according to the above formula, the offset d between the design curve and the secant, the pre-deflection angle α of each secant segment, and the angle β corresponding to the secant can be directly obtained; similarly, given the radius R of the design curve and the maximum allowable offset d... max Under the premise that a single secant segment can be deduce the maximum allowable length L. max The calculation formula is:

[0037] According to the formula, the only factors affecting the length of the secant are the design curve radius and the maximum offset of the sentence order. Therefore, the maximum length of the corresponding secant can be calculated based on the starting curve radius and the interval curve radius.

[0038] Optionally, in this embodiment, to ensure the final forming quality of the tunnel axis, there are strict requirements on the error of the secant fitting design curve. Therefore, the maximum value of the offset d between the design curve and the secant in the above calculation formula is d. maxThe tolerance must not exceed ±50mm. This value is a precision index determined based on a comprehensive consideration of multiple factors, including shield tunnel construction specifications, segment selection adaptability, and control of the impact on the surrounding environment. ±50mm is used as a constraint condition in L. max The calculation formula can be used to calculate the reasonable secant length that meets both the accuracy requirements and the needs of tunnel boring machine operation under a specific curve radius R.

[0039] Optionally, in this embodiment, the method for converting the determined secant parameters into spatial coordinates usable for construction is specified, referring to... Figure 4 First, a unified measurement coordinate system is established on the construction plan. For a pre-defined trajectory composed of multiple secant lines, its mathematical equation needs to be calculated segment by segment. Taking the adjacent i-th and j-th secant lines as an example: the i-th secant line is determined by its starting point A(xi,yi) and the intersection point P(x(ij), y(ij)) with the j-th secant line. Its linear equation can be expressed as: The j-th secant segment is determined by its intersection point P(x(ij), y(ij)) and its endpoint B(xj,yj), and its equation is:

[0040] Taking the j-th secant as an example: Yj is the ordinate of any point on the j-th secant; Xj is the abscissa of any point on the j-th secant; yi-j is the ordinate of the intersection point of the i-th secant and the adjacent j-th secant; xi-j is the abscissa of the intersection point of the i-th secant and the adjacent j-th secant; yj is the ordinate of the endpoint of the j-th secant; xj is the abscissa of the endpoint of the j-th secant; and bj is the intercept.

[0041] By sequentially calculating the coordinates of the starting point, intersection point, and ending point of all secant segments and their linear equations, the entire preset path of the tunnel boring machine is completely drawn in space. This preset path can be directly imported into the construction surveying system and the tunnel boring machine guidance system.

[0042] Optionally, in this embodiment, for step S2, before the starting bracket is installed, the starting guide rail needs to be positioned and measured, the starting guide rail needs to be installed, and a verification measurement needs to be performed after installation; the positioning measurement of the starting guide rail includes the following operations: Setting out the tunnel centerline: Using the approved starting edge control points, the tunnel centerline is set out on the bottom slab or side wall of the starting shaft.

[0043] Establishing tunnel elevation control lines and guide rail slopes: Using a level, establish the tunnel rail surface elevation control lines on the sidewall of the launching shaft; at the same time, in conjunction with the tunnel longitudinal slope design, calculate and mark the required installation slope of the launching guide rails (installed on the bracket).

[0044] Positioning the guide rail: Based on the laid-out tunnel centerline and slope line, and combined with the structural dimensions of the bracket and guide rail, the precise installation position of the starting guide rail on the bracket is finally determined.

[0045] After completing the above steps, the launching bracket is installed. First, the foundation is treated: in the predetermined installation area of ​​the launching well bottom plate, the surface laitance, oil stains and other debris are cleaned, the bottom plate concrete is roughened, and a fine stone concrete leveling layer is poured to provide a solid and flat bearing foundation for the bracket.

[0046] Rough adjustment and positioning: During hoisting, the base is initially aligned with the tunnel design centerline that has been laid out on the bottom plate to achieve basic positioning.

[0047] Fine-tuning and positioning: This involves two steps: elevation and slope adjustment, and centerline orientation adjustment. Elevation and slope adjustment: Using jacks and steel plate blocks of varying thicknesses, the base is repeatedly measured and precisely adjusted to the design elevation and slope using a level. Centerline orientation adjustment: Surveyors use a total station to fine-tune the shims and lateral jacking to ensure the base's centerline coincides with the tunnel's design centerline without lateral twisting.

[0048] Final Fixing: After the elevation, slope, centerline, and orientation of the base beam have all been measured and accepted and the deviations meet the requirements, the base beam is fixed. The base support is fully welded to the steel plate pre-embedded in the bottom plate of the well and anchored with anchor bolts. The combined action of welding and bolt anchoring ensures that the launching bracket has sufficient overall rigidity and stability when bearing the huge weight and launching thrust of the tunnel boring machine, preventing displacement or deformation during use.

[0049] Optionally, in this implementation, to ensure the accuracy of the starting benchmark, the tunnel centerline, elevation control line, and guide rail slope are set, and their deviation from the design values ​​should not exceed ±10mm. During construction, a total station and level are used for multiple checks, and the frame can only be fixed after meeting the standards. When installing the reaction frame, in addition to ensuring structural stability, measuring instruments are used to strictly control its spatial orientation, that is, the bearing plane of the reaction frame (the surface in contact with the shield tunneling jack) is perpendicular to the pre-set secant direction of the shield tunneling (i.e., the secant direction of the initial section). Typically, a total station is used to project the tunnel design axis onto the reaction frame installation position, and the center is adjusted to coincide with the axis. The error should also be controlled within ±10mm to ensure efficient transmission of thrust along the pre-set axis.

[0050] Optionally, in this embodiment, the specific operation procedure for zero-position calibration of the initial attitude of the tunnel boring machine in step S3 is as follows: establish marker points; select at least 8 positions on the lower half of the tunnel boring machine main body, weld or install forced centering prisms as zero-position marker points, the points should be evenly distributed to ensure a large spacing; use a high-precision automatic total station to accurately measure these prism points using the three-dimensional coordinate method, and the measurement error of the three-dimensional coordinates (X, Y, Z) of each marker point should be ≤ ±6mm.

[0051] Establish a conversion model: Based on the design drawings of the tunnel boring machine (TBM), the relative positional relationship between these prism points and the key geometric feature points of the TBM (such as the center of the cutterhead and the center of the shield tail) can be accurately determined. Through spatial coordinate transformation calculation, a precise conversion relationship is established. The parameters are then input into the TBM's automatic guidance system, and the system then knows the initial precise position and attitude of the TBM in space.

[0052] Optionally, in this embodiment, in step S4, when the tunnel boring machine (TBM) begins to advance and its front shield and articulated section enter the portal soil, the active articulation system is activated. The TBM automatic guidance system acquires and displays the real-time attitude of the TBM. The system compares the TBM attitude data with the preset secant trajectory in real time, calculates the deviation and trend of the current TBM in the horizontal and vertical directions relative to the preset trajectory, and uses the flexibility of the articulation to adjust the tunneling direction in a timely and minute manner. Based on the above deviation data, the active articulation control algorithm quickly calculates the adjustment amount of the articulation cylinder required to correct this deviation, and dynamically and continuously adjusts the stroke of the articulation cylinder to ensure that the TBM can start accurately and smoothly along the preset initial secant trajectory and smoothly transition to the next secant section.

[0053] Optionally, in this embodiment, the feedforward method in step S5 is as follows: During the secant tunneling stage, the system pre-reads the trajectory of the next secant segment according to the preset trajectory. Based on this angle and the parameters of the articulation system, the system pre-sets the target stroke difference of each group of articulation cylinders. The system will start calculating the target stroke difference that each group of cylinders of the active articulation system needs to achieve in order to realize this theoretical deflection angle, based on the current travel speed of the tunnel boring machine and other factors, a certain distance in advance. Then, the system gradually adjusts the articulation cylinders to the target state, so that the middle shield and front shield of the tunnel boring machine have already generated a gradual and guiding pre-bending posture before actually reaching the geometric turning point, which enables the tunnel boring machine to complete the zigzag turn more smoothly and naturally, reducing the sharp twist and mechanical stress at the turning point.

[0054] A system for active articulation initiation and tunneling construction of shield tunnels with small radius curves includes: The trajectory planning module is used to execute trajectory planning steps and generate a preset trajectory containing the coordinates of continuous secant segments. For example, it calculates the maximum secant length of a song line segment according to a formula, decomposes the design curve into continuous secant segments that meet the deviation requirements in the construction coordinate system, and calculates the coordinates of the starting point, intersection point and ending point of each secant segment.

[0055] The measurement and positioning module is used to perform the measurements in step S2, including but not limited to: measuring the coordinates output by the trajectory planning module in the launching shaft, the tunnel centerline, measuring the verticality of the reaction frame, and performing precise three-dimensional coordinate measurements of the shield machine zero-position marker point; measuring the tunnel elevation control line and the slope of the launching guide rail; running the measurement control software; and receiving coordinate data from the planning module.

[0056] The active articulated shield tunneling machine is equipped with an active articulation system. Its articulation cylinder group can actively and continuously adjust its stroke according to instructions, thereby flexibly changing the bending angle between the front shield and the middle shield / tail shield.

[0057] The guidance control system includes a real-time guidance unit, an articulation control unit, and a propulsion coordination unit. The real-time guidance unit continuously and frequently acquires the real-time spatial attitude of the tunnel boring machine, while the articulation control unit controls the active articulation system. The propulsion coordination unit intelligently adjusts the thrust and speed of each set of propulsion jacks according to the tunneling stage, attitude, and the needs of the articulation system to achieve smooth and efficient collaborative tunneling.

[0058] The embodiments described above merely illustrate implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for active articulation of shield tunneling on small-radius curves for launching and excavation, applicable to shield tunneling projects where both the launching shaft and the tunnel section are located on small-radius curve segments, and the horizontal curve radius of the section is smaller than the horizontal curve radius of the launching shaft, characterized in that... Includes the following steps: S1: Trajectory planning; The secant method is used for trajectory planning, which decomposes the design curve into multiple continuous secants that meet the deviation requirements, forming a preset shield tunneling trajectory that meets the preset deviation requirements. S2: Launch preparation; Based on the starting section direction of the preset trajectory, install and precisely position the launching bracket in the launching well; install the reaction frame perpendicular to the starting section's propulsion direction; S3: Equipment calibration; Assemble a tunnel boring machine with active articulation function on the launching bracket, and perform initial attitude zero-position calibration on the tunnel boring machine to establish the transformation relationship between the machine coordinate system and the construction coordinate system; S4: Cut-line initiation; the tunnel boring machine (TBM) begins to excavate along the preset trajectory; when the front of the TBM enters the portal soil, the active articulation system is activated, and the stroke of the articulation cylinder is adjusted in real time to make the TBM's posture dynamically follow the preset trajectory; S5: Securing tunneling; During the tunneling process along the preset trajectory, the stroke difference of the articulated cylinder is set in a feedforward manner to make the tunnel boring machine (TBM) form a pre-bending posture; At the same time, the thrust of the propulsion jack is adjusted to control the angle of the TBM, so that it can advance smoothly along the preset trajectory.

2. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 1, characterized in that, In step S1, the formula for calculating the initial attitude of the shield tunneling machine along the secant line of the small-radius curve segment is: Where L is the secant length, α is the pre-angle, β is the angle corresponding to the secant, d is the offset between the design curve and the secant, and R is the radius of the design curve. The formula for calculating the maximum length of a secant is: d max For the maximum allowable offset, L max This represents the maximum length of a single secant segment.

3. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 2, characterized in that, The offset d between the design curve and the secant line should not exceed ±50mm.

4. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 3, characterized in that, In step S1, the formula for calculating the coordinates of the i-th secant segment is: Where Yi is the ordinate of any point on the i-th secant line; Xi is the abscissa of any point on the i-th secant line; yi is the ordinate of the starting point of the i-th secant line; xi is the abscissa of the starting point of the i-th secant line; yi-j is the ordinate of the intersection point of the i-th secant line and the adjacent j-th secant line; xi-j is the abscissa of the intersection point of the i-th secant line and the adjacent j-th secant line; bi is the intercept. The formula for calculating the coordinates of the j-th secant segment is: Where Yj is the ordinate of any point on the j-th secant line; Xj is the abscissa of any point on the j-th secant line; yi-j is the ordinate of the intersection point of the i-th secant line and the adjacent j-th secant line; xi-j is the abscissa of the intersection point of the i-th secant line and the adjacent j-th secant line; yj is the ordinate of the endpoint of the j-th secant line; xj is the abscissa of the endpoint of the j-th secant line; and bj is the intercept. The coordinates of each secant segment are calculated using the formulas for calculating the coordinates of the i-th and j-th secant segments mentioned above.

5. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 1, characterized in that, In step S2, before installing the launching bracket in the launching shaft, the launching guide rail needs to be positioned and measured. The position of the tunnel centerline and the guide rail is laid out through the launching side control point, and the tunnel elevation control line and guide rail slope are measured by leveling method.

6. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 5, characterized in that, The positioning error of the tunnel centerline, elevation control line and guide rail slope shall not exceed 10mm; when installing the reaction frame, ensure that its force plane is perpendicular to the pre-set secant advance direction of the shield machine.

7. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 1, characterized in that, In step S3, the equipment calibration step is as follows: at least 8 forced centering prisms are set on the stable structure of the tunnel boring machine as zero-position markers, and the coordinates of the zero-position markers are measured by the three-dimensional coordinate method, with a measurement error of ≤±6mm; a conversion model is established based on the coordinates of the zero-position markers, the geometric coordinates of the tunnel boring machine cut center and the shield tail center.

8. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 1, characterized in that, In step S4, after the shield and articulated section of the tunnel boring machine enter the soil at the tunnel entrance and the active articulation system is activated, the real-time attitude of the tunnel boring machine displayed by the guidance system is compared in real time with the preset initial secant trajectory in the trajectory planning step. Based on the attitude deviation data generated by the real-time comparison, the stroke of the hydraulic cylinder of the active articulation system is dynamically adjusted to continuously and slightly correct the tunnel boring machine's excavation direction, ensuring that it starts smoothly along the preset initial secant trajectory and transitions to the subsequent secant segment.

9. The method for active articulation starting and tunneling construction of a shield tunnel with a small radius curve secant line according to claim 8, characterized in that, In step S5, the stroke difference of the articulated cylinder is set in a feedforward manner as follows: based on the curvature change of the preset trajectory, the target stroke difference of the articulated cylinder required to generate a deflection angle between the middle shield and the front shield of the tunnel boring machine is calculated in advance.

10. A system for active articulation initiation and tunneling construction of a shield tunnel with small radius curve secant, employing the construction method described in any one of claims 1-9, characterized in that, include: The trajectory planning module is used to execute the trajectory planning steps and generate a preset trajectory containing the coordinates of continuous secant segments; The measurement and positioning module is used to perform the measurements in the initial preparation step S2; The active articulated tunnel boring machine is installed on a precisely positioned launching guide rail and has completed zero-position calibration. The guidance and control system, integrated on the active articulated shield machine, is used to execute the secant initiation step S4 and the secant tunneling step S5, and includes: a real-time guidance unit for acquiring the real-time attitude of the shield machine; The articulation control unit receives real-time attitude data and preset trajectories, calculates and outputs articulation cylinder stroke adjustment commands; the propulsion coordination unit adjusts the zoned thrust of the propulsion jacks according to the tunneling stage and attitude requirements, and works in coordination with the articulation control unit.

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