Steel frame perpendicularity control method and system in TBM tunnel construction

Abstract

The invention discloses a steel frame perpendicularity control method and system in TBM tunnel construction, and belongs to the technical field of tunnel construction measurement. The method adopts a control flow of three-stage remeasurement of a projector, a gradienter fixture and a total station, and comprises the following steps: firstly, fixing the projector on a TBM shield, projecting an arch frame contour to a rock surface according to design parameters, and realizing rapid preliminary positioning of a steel frame; then, a plurality of special clamps integrated with strip-type gradienter are installed on the key section of the steel frame, perpendicularity deviation is calculated according to a formula by reading data of the gradienter, meanwhile, the distance is checked through the clamp structure, and accurate measurement and real-time adjustment are achieved; and finally, the total station is used for carrying out overall re-testing and receiving on the steel frame which is continuously installed for multiple trusses. The invention further discloses a special gradienter fixture and a positioning system comprising the special gradienter fixture. The method solves the problems that a traditional method is low in efficiency, poor in precision and rough in adjustment in the TBM construction environment.

Description

A method and system for controlling the verticality of steel frames in TBM tunnel construction Technical Field

[0001] This invention relates to the field of tunnel construction engineering surveying and support structure installation technology, specifically to a method and system for controlling the verticality of the initial support steel frame installation during tunnel boring machine (TBM) construction. Background Technology

[0002] During TBM tunnel construction, the steel frame serves as the core load-bearing structure for the initial tunnel support. Its verticality directly determines the stability, load-bearing capacity, and subsequent lining quality of the support system. Excessive deviation in the verticality of the steel frame can lead to uneven stress distribution, resulting in localized stress concentration under the pressure of the surrounding rock. This can cause safety hazards such as steel frame deformation, cracking, and even tunnel collapse.

[0003] Currently, the installation of initial support steel frames in TBM tunnels mainly relies on two methods: one is "manual plumb bob + measuring tape" measurement, which is easily affected by wind flow and TBM mechanical vibration within the tunnel, with an error of 1°–2°; the other is "single total station without prism" measurement, which directly places the measuring point on the edge of the steel frame flange, but the unevenness and corrosion of the steel frame surface can cause the measuring point to drift by 3–5mm, resulting in a verticality error ≥0.3°. Both methods lack dedicated clamps in the adjustment stage. Workers usually use rulers for temporary measurements or rely on measuring guide points for long-term fixed-point measurements, resulting in a "measurement-adjustment-verification" cycle of up to 25 minutes for a single steel frame, causing construction at the tunnel face to stagnate, inefficiency, and prolonged exposure of personnel to the risk of working at the excavation face.

[0004] Bar levels, commonly used for measuring small angles, can accurately measure the minute tilt angles of components relative to the vertical. Utilizing the principle of constant liquid level, they display angular displacement via a spirit level, offering high resolution and ease of operation. Projectors, based on optical projection technology, can project the outline of an object onto the surrounding rock, achieving non-contact positioning. How to systematically integrate these tools to solve the challenge of controlling the verticality of steel frames in TBM construction scenarios characterized by strong vibrations, confined spaces, and rapid excavation has become a pressing issue in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the verticality of steel frames in TBM tunnel construction in order to solve the above-mentioned problems. Its core is to use a projector for rapid preliminary positioning, use multi-section level gauges for precise measurement and fine-tuning, and finally use a total station for overall retesting and acceptance, forming a three-level quality control closed loop.

[0006] This invention achieves the above objectives through the following technical solution: A method for controlling the verticality of steel frames in TBM tunnel construction, comprising the following steps: Projection positioning step: The projector is fixed on the TBM shield, and the arch frame outline is projected onto the tunnel excavation rock surface according to the preset arch frame design parameters. Construction personnel perform preliminary positioning and installation of the steel frame based on the projected outline; Fixture precision measurement and adjustment step: Level fixtures are installed at multiple designated sections of the initially positioned steel frame. The verticality deviation of the steel frame is calculated by reading the measurement data of the level on each fixture, and the spacing between adjacent arch frames is simultaneously detected using the structure of the fixtures; When the verticality deviation or spacing deviation exceeds the preset allowable deviation value, the position of the steel frame is adjusted and remeasured until it meets the requirements; Overall retesting and acceptance step: After the fixture precision measurement and adjustment steps are completed for multiple consecutive steel frames, the overall verticality, spacing, and linearity of the batch of steel frames are retested using a total station.

[0007] Preferably, the designated section includes the waist of the steel frame, the left and right ends of the arch bottom and the arch top, and the number of level gauges installed at each designated section is not less than 5.

[0008] Preferably, the level fixture includes a fixture body and a strip level mounted thereon. The fixture body is provided with a clamping part and a positioning reference surface that are adapted to the shape of the steel frame flange.

[0009] Preferably, the verticality deviation is calculated according to the formula F=C×L×Δ, where F is the line deviation, C is the graduation value of the bar level, L is the length of the specified section, and Δ is the number of readings of the level of the bar level.

[0010] Preferably, the projector is an industrial projector, which is mounted on the steel support frame of the TBM shield, and the height and angle of the steel support frame are adjustable.

[0011] Preferably, the projection direction of the projector is perpendicular to the cross section to be measured of the steel frame, and the projection distance is 1.5 meters to 2.5 meters.

[0012] Preferably, after the overall retest and acceptance step, the level gauge clamp remains on the steel frame until it is removed within a specified time before the precast arch block installation process begins.

[0013] Based on the above method, the present invention also provides a dedicated level fixture, comprising a fixture body and a strip level fixed thereon. The fixture body is provided with a clamping structure adapted to the shape of the steel frame flange and a positioning reference surface for conforming to the surface of the steel frame. The measuring reference surface of the strip level is parallel to or has a defined geometric relationship with the positioning reference surface of the fixture body, ensuring that the measured value directly reflects the posture of the steel frame. The fixture body is also provided with connecting steel pipes for limiting the spacing of the arch frames, and the fixture body is installed at both ends of the connecting steel pipes.

[0014] Furthermore, the present invention provides a TBM steel frame installation and positioning system, which includes: a projection positioning unit: consisting of an industrial projector, an adjustable steel support frame and a dust cover, fixed to the TBM shield, for realizing rock surface projection positioning.

[0015] Measurement and adjustment unit: Composed of multiple level clamps as described above, used for precise measurement and auxiliary adjustment of verticality and spacing when mounted on a steel frame.

[0016] Overall retesting unit: Composed of a total station, used to perform final overall geometric parameter retesting and acceptance of the assembled steel frame.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: 1. By densely deploying multiple cross-sections and clamps and directly measuring with a high-precision strip level, the accuracy of single-point verticality measurement is improved to 0.2°, which is superior to the ≥0.3° of the traditional total station prism-free method; 2. The projector enables rapid preliminary positioning of the steel frame, the level clamps achieve a close integration of measurement and adjustment, and the total station enables batch re-measurement, significantly reducing the total time for "measurement, adjustment, and re-measurement" of a single steel frame from the traditional 25 minutes to approximately 5 minutes; 3. Dedicated clamp structure. Simple, robust, purely mechanically operated, lightweight (approximately 2.3kg), quick to assemble and disassemble, designed for over 100 cycles of use, with a cost per steel frame less than 15 yuan; 4. Employing a purely mechanical adjustment method eliminates the need for power supply and hydraulic circuits, thus removing explosion-proof risks within the tunnel; multi-stage retesting ensures closed-loop quality control; the temporary support provided by clamps enhances the stability of the steel frame before secondary lining; the application of this method can eliminate the secondary frame adjustment process at the working face, significantly reducing the exposure time of workers at the excavation face by over 60%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0019] Figure 1 is a logic block diagram of a steel frame verticality control method in TBM tunnel construction according to the present invention.

[0020] Figure 2 is a schematic diagram of the front view of the level gauge clamp described in this invention.

[0021] Figure 3 is a top view of the structure of the level gauge clamp described in this invention.

[0022] Figure 4 is a schematic diagram of the projector retesting system being arranged in the TBM construction environment according to an embodiment of the present invention.

[0023] Figure 5 is a schematic diagram of the arrangement of the level gauge clamp in the TBM construction environment according to an embodiment of the present invention.

[0024] The following are the annotations in the attached diagram: 1. Fixture body; 2. Bar level; 3. Connecting steel pipe; 4. Projector; 5. Steel support frame; 6. TBM shield. Detailed Implementation

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0027] The invention will be further described below with reference to the accompanying drawings: The steel frame verticality control method provided by the invention follows the logical flow shown in Figure 1, mainly including three stages: first, rapid preliminary positioning is performed using a projector; then, precise measurement and real-time adjustment are performed using a dedicated level fixture; finally, batch overall retesting and acceptance are conducted using a total station. These three stages are interconnected, forming a complete quality control closed loop, which is especially suitable for situations where high efficiency and accuracy of steel frame installation are required during TBM tunneling.

[0028] The following uses a TBM tunnel construction project as an example to illustrate the specific implementation process of this method, which includes the following steps: Step S1: Construction preparation stage: In terms of equipment preparation, it is necessary to configure a special level fixture, projection positioning unit and total station; the structure of the level fixture is shown in Figures 2 and 3, consisting of fixture body 1 and strip level 2; the fixture body is made of high-strength lightweight material, and the inner side is machined with V-grooves that match the steel frame flange to ensure a stable and close fit; the strip level is a high-precision model with a graduation value of 0.02mm / m, which is firmly installed on the fixture body, and its measuring reference plane is strictly parallel to the positioning reference plane of the fixture; some fixtures can be connected... The steel frame spacing is synchronously controlled via connecting steel pipes. The projection positioning unit, as shown in Figure 4, includes an industrial projector 4, a multi-directionally adjustable steel support frame 5, and a dust cover. The steel support frame is securely installed on the TBM shield. A total station with an angular measurement accuracy of at least 1″ is required. For benchmark establishment, a precise construction control network needs to be established in the already formed section of the tunnel, and the benchmark should be transferred to the vicinity of the TBM operating area. Simultaneously, the design parameters such as the arch frame outline and spacing are input into the projector control system. Step S2: First stage: Projection positioning: As shown in Figure 4, the projector 4 is installed at a suitable position in front of or on top of the TBM shield 6 via the steel support frame 5. The support frame is adjusted... The projector's optical axis is positioned approximately perpendicular to the rock surface at the arch waist of the steel frame to be installed. The focus is adjusted to ensure a clear, distortion-free outline of the arch frame is projected onto the excavated rock surface within a projection distance of 1.5 to 2.5 meters. The projector is then activated, and the design outline is projected onto the rock surface. Based on this clear light and shadow boundary, the installers hoist the steel frame and initially place it in the designated area, completing the rough positioning. Step S3: Second Stage: Fixture Precision Measurement and Adjustment: As shown in Figure 5, at least five level fixtures are evenly installed on each of the five key sections—the arch top, left and right arch waists, and left and right arch bottoms—on the initially positioned steel frame. During installation, it is essential to ensure that the fixtures are securely clamped to the steel frame flanges. The bottom surface of the level should be completely flush with the upper surface of the flange. If it is necessary to control the tenon distance, a pair of clamps with connecting steel pipes can be used to install at the corresponding positions of adjacent steel frames. After the clamps are installed stably, the number of divisions Δ of the bubble center of each bar level is read from the zero position. The verticality line deviation is calculated according to the formula F=C×L / 1000×Δ. Where F is the line deviation (mm), C is the level graduation value (mm / m), L is the effective detection length of the measurement section (mm), and Δ is the number of bubble offset divisions. For example, when L=500mm, C=0.02mm / m, and Δ=2 divisions is read, F=0.02×500 / 1000×2=0.0.02mm; This value represents the offset of the top of the steel frame at this point relative to the ideal vertical position; At the same time, check whether the spacing between adjacent steel frames meets the design allowable error; Compare the calculated F value of each point with the preset allowable deviation (such as 25mm) and judge whether the spacing is qualified; If a point exceeds the limit, the construction personnel immediately use jacks, steel wedges and other tools to make a small adjustment to the steel frame at the corresponding position, and observe the movement of the bubble of the relevant level instrument in real time as feedback; After adjustment, remeasure and calculate until the deviation and spacing of all measuring points of the section meet the requirements; At this point, the fine adjustment of a single steel frame is completed; Step S4: Third stage: Total station overall retest and acceptance: After continuously installing and adjusting a batch (such as 3-5 frames) of steel frames, this stage of retest is carried out; The surveyor sets up a station at the rear-mounted stable position and uses a total station to perform an overall scan measurement of the batch of steel frames to accurately obtain each feature point. The three-dimensional coordinates are obtained; the measurement data is imported into professional software for analysis, fitting the actual spatial posture of each steel frame, calculating its overall verticality, adjacent spacing, and the smoothness of the arc formed by multiple frames; the analysis results are compared with the final acceptance standard; if all parameters are qualified, the acceptance is passed and the data is archived; if individual deviations are found, they are located at specific positions for fine adjustment, and monitored in real time by a total station until qualified; Step S5: Clamp recycling: After the overall retest and acceptance, the level clamps are not removed temporarily and are left on the steel frame to provide temporary auxiliary stability for the steel frame; before the tunnel is excavated forward and subsequent processes such as the precast invert arch are prepared, all clamps are quickly disassembled, cleaned, and inspected by designated personnel, and then transported to the front working face for the next cycle of steel frame installation; the clamps are robustly designed and can be reused more than a hundred times, with low amortization costs.

[0029] The systematic application of this method achieves comprehensive benefits, including high steel frame installation accuracy, fast operation speed, good personnel safety, closed-loop quality control, and low tool costs, effectively overcoming the drawbacks of traditional methods.

[0030] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for controlling the verticality of steel frames in TBM tunnel construction, characterized in that, Includes the following steps: Projection positioning steps: Fix the projector (4) on the TBM shield (6), and project the arch frame outline onto the tunnel excavation rock surface according to the preset arch frame design parameters. The construction personnel will perform preliminary positioning and installation of the steel frame based on the projected outline. Fixture precision measurement and adjustment steps: Install level fixtures at multiple designated sections of the pre-positioned steel frame, calculate the verticality deviation of the steel frame by reading the measurement data of the level on each fixture, and use the structure of the fixture to synchronously detect the spacing between adjacent arch frames. When the verticality deviation or spacing deviation exceeds the preset allowable deviation value, adjust the position of the steel frame and remeasure until it meets the requirements. Overall retesting and acceptance steps: After completing the fixture precision measurement and adjustment steps for multiple steel frames, use a total station to retest the overall verticality, spacing, and linearity of the batch of steel frames.

2. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 1, characterized in that, The designated cross-section includes the arch waist, the left and right ends of the arch bottom, and the arch top of the steel frame, and the number of level gauges installed at each designated cross-section shall not be less than 5.

3. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 1, characterized in that, The level fixture includes a fixture body (1) and a strip level (2) mounted thereon. The fixture body (1) is provided with a clamping part and a positioning reference surface that are adapted to the shape of the steel frame flange.

4. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 3, characterized in that, The verticality deviation is calculated according to the formula F=C×L×Δ, where F is the line deviation, C is the scale division of the bar level (2), L is the length of the specified section, and Δ is the number of readings of the level of the bar level (2).

5. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 1, characterized in that, The projector (4) is an industrial projector, which is installed on the steel support frame (5) of the TBM shield (6), and the height and angle of the steel support frame (5) are adjustable.

6. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 5, characterized in that, The projection direction of the projector (4) is perpendicular to the cross section to be measured of the steel frame, and the projection distance is 1.5 meters to 2.5 meters.

7. The method for controlling the verticality of steel frames in TBM tunnel construction according to claim 1, characterized in that, After the overall retest and acceptance step, the level gauge clamp remains on the steel frame until it is removed within a specified time before the precast arch block installation process begins.

8. A leveling fixture for use in a method for controlling the verticality of a steel frame in TBM tunnel construction according to any one of claims 1 to 7, characterized in that, include: The clamp body (1) has a clamping structure for clamping onto the flange of the steel frame; and a bar level (2) is fixedly installed on the clamp body (1), and its measuring reference surface is parallel to or has a defined geometric relationship with the positioning reference surface of the clamp body (1).

9. The level fixture according to claim 8, characterized in that, The clamp body (1) is also provided with a connecting steel pipe (3) for limiting the spacing of the arch frame, and the clamp body (1) is installed at both ends of the connecting steel pipe (3).

10. A TBM steel frame installation and positioning system, characterized in that, A method for controlling the verticality of a steel frame in TBM tunnel construction according to any one of claims 1 to 7, comprising: a projection positioning unit, which includes a projector (4) fixed to the TBM shield (6) and an adjustable steel support frame (5) for projecting the design outline of the arch frame onto the rock surface; a level fixture for measuring verticality and spacing on the steel frame; and a total station for re-measuring the overall geometric parameters of the assembled steel frames.

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