Tunnel construction surveying method
By employing pre-construction design and post-construction adjustment methods, the problem of low accuracy in traditional tunnel construction surveying was solved, achieving efficient and precise tunnel construction surveying and ensuring that the tunnel's linearity meets design requirements.
Patent Information
- Application Number
- CN202610404071.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-30
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional tunnel construction surveying methods suffer from low measurement accuracy, complex operation, and low efficiency, making it difficult to meet the high standards required for modern tunnel engineering.
Before tunnel construction, control surveying design is carried out based on the propagation law of measurement errors. Horizontal and vertical control points are set up, and measurements are taken using GPS and total station to establish a main control network for cross-traverse. Tunnel construction layout is carried out, and error measurement and adjustment are carried out after the tunnel is completed.
It improved the measurement accuracy and efficiency of tunnel construction, ensured that the tunnel linearity met the design requirements, and reduced the propagation of measurement errors and human error.
Smart Images
Figure CN122384757A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of tunnel construction technology, and in particular to a tunnel construction surveying method. Background Technology
[0002] Tunnel construction surveying is a crucial step in tunnel engineering, and its accuracy directly impacts the construction quality and safety of the tunnel. Traditional tunnel construction surveying methods suffer from low accuracy, complex operation, and low efficiency, making it difficult to meet the high standards required for modern tunnel engineering. Therefore, there is an urgent need to design an efficient and accurate tunnel construction surveying method. Summary of the Invention
[0003] This invention provides a tunnel construction surveying method to address the shortcomings of existing tunnel construction surveying methods, such as low measurement accuracy, complex operation, and low efficiency, thereby achieving a highly efficient and accurate tunnel construction surveying method.
[0004] This invention provides a tunnel construction surveying method, comprising: Before tunnel construction, control measurement design should be carried out based on the propagation law of measurement errors. Layout horizontal and vertical control points near the tunnel entrance for control surveying of the tunnel entrance; A cross-traverse main control network is set up inside the tunnel, and control measurements inside the tunnel are carried out based on the cross-traverse main control network set up inside the tunnel. Using a total station to measure the traverse lines inside the tunnel, the tunnel construction layout was carried out. After the tunnel is completed, the breakthrough error is measured and adjusted.
[0005] According to the tunnel construction surveying method provided by the present invention, the tunnel control surveying design includes: Based on the requirements for tunnel length, shape, and breakthrough accuracy, a mathematical model of the traverse network is established to simulate the error propagation path. The least squares method is used to perform adjustment calculations on the survey network, thereby optimizing the layout of traverse points and the level of measurement accuracy.
[0006] Determine the accuracy level and implementation plan for horizontal control surveying and vertical control surveying.
[0007] According to the tunnel construction surveying method provided by the present invention, the portal control surveying includes: At least three plane control points are set up near the tunnel entrance to ensure that the plane control points can cover the tunnel entrance area, and the distance between adjacent plane control points is 200m to 500m.
[0008] At least two elevation control points are set up near the tunnel entrance, and the elevation control points are shared with the horizontal control points or set up separately.
[0009] Ensure that the horizontal control point and the vertical control point are mutually visible, that the foundation of the horizontal control point and the vertical control point is stable, and that they are visible to the excavated opening.
[0010] GPS combined with a total station was used to conduct control measurements outside the tunnel, and joint measurements were carried out with control points of adjacent roadbeds or bridges.
[0011] According to the tunnel construction surveying method provided by the present invention, ensuring that the horizontal control point and the vertical control point are mutually visible includes: The horizontal control points and the vertical control points are set up at locations with high elevation and open views.
[0012] The visibility between the horizontal control points and the vertical control points is checked visually and with the aid of auxiliary tools.
[0013] Clear vegetation between the horizontal control point and the vertical control point, remove buildings or temporary facilities, and ensure unobstructed visibility between the horizontal control point and the vertical control point.
[0014] Adjust the positions of the horizontal control points and the vertical control points or add the horizontal control points and the vertical control points according to the visibility requirements.
[0015] Use measuring instruments to retest the visibility and record the visibility status.
[0016] Regularly inspect and promptly remove any new obstacles to ensure visibility.
[0017] According to the tunnel construction surveying method provided by the present invention, the stability of the foundation where the plane control points and the elevation control points are located is ensured by the following means: Understand the geological conditions of the foundation where the plane control points and the elevation control points are located, assess the bearing capacity and stability of the foundation, and select a rock foundation or a concrete foundation.
[0018] Install permanent markers, ensure that the markers are firmly bonded to the foundation, and reinforce the foundation.
[0019] Regularly monitor the displacement of the horizontal control points and the vertical control points, and record and report any abnormalities.
[0020] According to the tunnel construction surveying method provided by the present invention, the in-tunnel control surveying includes: Multiple first traverse points are set up along the centerline of the tunnel, and multiple second traverse points are set up along one side of the tunnel. The first traverse points and the second traverse points are set up in a one-to-one correspondence to form the main control network of the intersecting traverses.
[0021] Using the baseline control points of the traverse as elevation control points, a pair of elevation control points are set up every 100m inside the tunnel.
[0022] Using traverse points that are close to the tunnel entrance and have good visibility, the total station is used to backsight other traverse points. The azimuth angles from each traverse point to the tunnel entrance traverse point are measured, and the average value is taken as the azimuth angle of the traverse reference point from the tunnel entrance traverse point.
[0023] Based on the aforementioned cross-traverse main control network, a total station is used to perform precise traverse surveying, and the control network adjustment and centerline adjustment within the tunnel are carried out to complete the centerline measurement within the tunnel.
[0024] Two leveling points are set up at the tunnel entrance. Based on these leveling points, a level instrument is used to conduct precise leveling measurements. Then, the elevation control points are observed back and forth to ensure that the observation limits and accuracy meet the specified accuracy requirements, so as to complete the elevation measurement inside the tunnel.
[0025] According to the tunnel construction surveying method provided by the present invention, the step of using a total station to measure and set out the tunnel construction using an in-tunnel traverse includes: Set the total station at the centerline point inside the tunnel to determine the center of the tunnel face arch, and determine the excavation section based on the center of the tunnel face arch.
[0026] After the excavation is completed, a cross-section inspection instrument is used to check the excavation cross-section. Once the requirements are met, a total station is used to accurately determine the position of the steel support to ensure the accuracy of the tunnel centerline and elevation.
[0027] Before the lining trolley is in place, the centerline is laid out and the elevation is measured for the lining section. After the lining trolley is in place, the position and structural dimensions of the trolley are checked by plumb line and measuring tape using the laid-out centerline and elevation points. After the lining construction is completed, the centerline and elevation of the lining section are checked, and the net cross-section after lining is measured.
[0028] The excavation proceeds forward, and construction guide lines are laid out to guide the excavation layout.
[0029] According to the tunnel construction surveying method provided by the present invention, when the excavation face advances forward, the side length of the construction traverse laid out is 150m to 250m in the straight section of the tunnel and 60m to 100m in the curved section.
[0030] Every 200m to 300m of tunneling, a section of the construction traverse is selected, and a basic traverse with a high precision of no less than 200m is laid. The basic traverse is used to check whether the direction of the tunnel is consistent with the design, so as to reduce the transmission and accumulation of measurement errors.
[0031] According to the tunnel construction surveying method provided by the present invention, after the tunnel is completed, the determination and adjustment of the completion error includes: At the tunnel breakthrough face, the coordinate method is used to determine the plane coordinates of the breakthrough point from both ends of the tunnel, and the measurement results are transferred to the breakthrough cross section and centerline to calculate the transverse breakthrough error and the longitudinal breakthrough error.
[0032] After the tunnel is completed, leveling is used to determine the elevation of the connection point from both ends of the tunnel, and the difference is the vertical connection error.
[0033] The completed underground traverse is used as a traverse for adjustment, and the centerline point of the line is adjusted according to the adjusted coordinate values; the completed underground leveling line is used as a traverse for adjustment, and the average elevation of the measured connection point at both ends is taken as the adjusted elevation value.
[0034] The adjusted centerline coordinates and elevation values are used as the starting data for the final clearance measurement and line adjustment. A laser profiler or total station is used to measure the tunnel clearance profile to check whether the position of the line and structure meets the design requirements.
[0035] The tunnel construction surveying method provided by this invention optimizes the traverse layout through controlled surveying design, avoiding error propagation and amplification; the cross-traverse network improves the cross-calibration capability of survey data and reduces the impact of single errors; total station measurement and forced centering reduce human operation errors, making construction layout more accurate; and the breakthrough error adjustment ensures that the overall linearity of the tunnel meets the design requirements, improving construction efficiency and quality. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0037] Figure 1 A flowchart of the tunnel construction surveying method provided by the present invention.
[0038] Figure 2 This is a schematic diagram of the main control network for the intersecting conductors inside the tunnel. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0040] Figure 1 A flowchart illustrating the tunnel construction surveying method provided by this invention is provided.
[0041] Figure 2 A schematic diagram of the main control network for intersecting conductors inside a tunnel is provided.
[0042] Figure reference numerals: SD1, SD2, SD3, SD0, SD 00 These are the traverse points near the tunnel entrance, Z1, Z2, ... Z n To establish points along the tunnel centerline; B1, B2, ... B n To establish points along one side of the tunnel; each traverse point also serves as a leveling point, which can be determined through precise geometric leveling. i With Z i The stability of the guide points is checked by measuring the elevation difference.
[0043] Reference Figure 1 and Figure 2 The tunnel construction surveying method provided by this invention includes the following steps: S1. Before tunnel construction, design control measurements inside the tunnel based on the propagation law of measurement errors; S2. Set up horizontal and vertical control points near the tunnel entrance and conduct entrance control measurements; S3. Lay out a cross-traverse main control network inside the tunnel, and conduct control measurements inside the tunnel based on the cross-traverse main control network laid out inside the tunnel. S4. Using a total station to measure the traverse line inside the tunnel, the tunnel construction layout is carried out; S5. After the tunnel is completed, the breakthrough error is measured and adjusted.
[0044] Reference Figure 1 In some embodiments of the present invention, step S1 includes: Before tunnel construction, horizontal and vertical control surveying designs are carried out inside the tunnel. Data analysis is then used to optimize these designs to ensure the accuracy of tunnel layout and the precision of tunnel breakthrough.
[0045] Specifically, during the design of the tunnel's horizontal control survey, a mathematical model of the traverse network is established based on the tunnel's length and shape. This model simulates the propagation path of measurement errors, determines the optimal layout of traverse points and the required accuracy level, and uses metal survey markers. These markers are fixed to the stable rock mass of the tunnel floor or sidewalls by concrete pouring. The fixing method involves welding pre-embedded steel bars to the base of the survey markers, followed by concrete pouring to form an integral structure. During the design of the elevation control survey, the leveling route and point spacing are determined based on the principles of leveling. Leveling points are made of stainless steel and have anchor hooks at their bottom. They are fixed to the tunnel floor by embedding concrete piles, with the pile depth exceeding the loose layer to ensure stability. Data analysis employs the least squares method for traverse network adjustment calculations. During design optimization, the point layout is adjusted to mitigate the impact of errors, ensuring the accuracy of tunnel layout and completion.
[0046] This embodiment utilizes detailed horizontal and vertical control surveying design before construction, optimizes the surveying network using error propagation laws and data analysis, and controls the accumulation of measurement errors from the design stage. Fixed survey markers and concrete foundations ensure the stability of the points, reducing the impact of construction disturbances. Rigorous data adjustment methods are employed to optimize the surveying scheme, improving the reliability and accuracy of the measurement data. Beneficial effects include: the optimized control surveying design reduces the risk of breakthrough errors and improves the measurement accuracy of tunnel construction; stable point layout ensures long-term measurement consistency; and data analysis optimization ensures the economy and effectiveness of the surveying scheme, thereby supporting accurate tunnel breakthrough and layout.
[0047] In some embodiments of the present invention, step S2 includes: S2.1 At least three plane control points are set up near the tunnel entrance to ensure that the plane control points can cover the tunnel entrance area, and the distance between adjacent plane control points is 200m to 500m.
[0048] S2.2 At least two elevation control points are set up near the tunnel entrance. The elevation control points are shared with the plane control points or set up separately.
[0049] S2.3 Ensure that the plane control point and the elevation control point are mutually visible, that the foundation of the plane control point and the elevation control point is stable, and that they are visible to the excavated opening.
[0050] S2.4. Use GPS combined with a total station to conduct control measurements outside the tunnel and connect them with control points of adjacent roadbeds or bridges.
[0051] Specifically, horizontal control points are established using concrete observation piers fixed to the ground. The piers are reinforced with embedded steel mesh to enhance structural strength, and a stainless steel centering plate is installed at the top, connecting to the measuring instruments via bolt holes. The foundations of the observation piers are excavated to stable ground and then integrally cast in concrete to form a permanent structure. Elevation control points can be established using independent concrete piles, with stainless steel leveling markers embedded at the top and fixed inside the piles via threaded connections. Alternatively, elevation control points can share the observation pier structure with horizontal control points, with stainless steel leveling markers embedded on the sides and fixed to the sidewalls by welding. All control points are positioned to ensure mutual visibility and maintain visibility to the tunnel entrance. Control point foundations are selected in stable rock areas, avoiding areas with fill or potential settlement. GPS measurement points require unobstructed views, and total station measurement points must be free from obstructions.
[0052] A suitable location was selected near the tunnel entrance, and a foundation pit was excavated to a stable stratum according to design requirements. A concrete foundation was then poured to form observation piers. A forced centering plate was installed on the top of the observation piers, and leveling markers were pre-embedded on the sides. After the setup was completed, a GPS receiver was used to measure the coordinates of the horizontal control points, and a level was used to measure the elevation of the vertical control points. During the measurement, coordination with adjacent roadbed and bridge control points was strengthened. All measurement data underwent adjustment calculations to ultimately determine the precise coordinates and elevations of the control points.
[0053] This embodiment ensures the stability of control points by employing concrete observation pier structures, reducing point displacement caused by external factors; improves instrument installation accuracy and reduces centering errors through a forced centering device; leverages the advantages of both GPS and total station measurement methods to improve measurement efficiency; and ensures the integrity and consistency of the measurement network through joint measurements with adjacent control points. Beneficial effects include: a stable foundation structure ensures long-term stability and reliability of control points; the combination of multiple measurement methods improves measurement accuracy and efficiency; and a comprehensive joint measurement scheme ensures that control measurements are consistent with the overall engineering coordinate system, providing a reliable benchmark for accurate tunnel breakthrough.
[0054] In some embodiments of the present invention, ensuring mutual visibility between the horizontal control points and the vertical control points in step S2.3 includes: ① selecting a location with higher terrain and a wide field of vision as the control point; ② checking the visibility between the control points visually and with auxiliary tools; ③ clearing vegetation, removing buildings or temporary facilities to ensure unobstructed visibility; ④ adjusting the position of the control points or adding control points according to the visibility requirements; ⑤ re-measuring the visibility using measuring instruments and recording the visibility status; ⑥ regularly checking and promptly clearing new obstacles to ensure visibility.
[0055] Specifically, when selecting control points at locations with higher elevations and open views, the control points are fixed to stable foundations using concrete observation piers, with enlarged foundations at the base of the piers to enhance stability. When checking the visibility between control points visually and using auxiliary tools, including laser rangefinders and theodolites, the laser rangefinder is temporarily mounted on a tripod at the control point, and the theodolite is fixed to the control point's forced centering plate using base screws. When clearing vegetation, felling tools are used to remove tree branches, and engineering machinery is used for demolition when removing buildings or temporary facilities. When adjusting the control point positions according to visibility requirements, movable temporary survey markers are used for trial placement, and these markers are fixed to the ground with ground stakes. When re-measuring visibility using surveying instruments, a total station is fixed to the top of the control point's observation pier using a forced centering device, and forward and reverse observations are performed to check visibility. A patrol system is established for regular inspections, and any new obstacles discovered are promptly removed by a clearing team.
[0056] First, survey the terrain of the tunnel entrance area, selecting high-lying locations with unobstructed views as candidate control point locations. Use visual methods to initially assess visibility, supplemented by precise checks with tools such as laser rangefinders and theodolites. Trim or remove vegetation obstructing visibility, and dismantle or relocate buildings or temporary facilities. Adjust the control point layout based on the inspection results, adding auxiliary control points as necessary. Perform a final visibility check using surveying instruments such as a total station, and record the visibility details in detail. Establish a regular inspection system during construction to promptly identify and remove any newly appearing obstacles, ensuring good visibility between control points at all times.
[0057] This embodiment ensures visibility from the outset by selecting control points at optimal geographical locations; comprehensively assesses visibility through a combination of inspection methods; dynamically maintains visibility through timely obstacle removal and point adjustments; and ensures continuous and reliable visibility performance through instrument re-measurement and record keeping. Beneficial effects include: optimized point selection provides excellent observation conditions for surveying work; multi-level visibility checks guarantee the accuracy of assessment results; timely maintenance measures ensure the long-term stability of visibility conditions; and a comprehensive record-keeping system provides reference for subsequent surveying work, ultimately guaranteeing the accuracy and efficiency of tunnel control surveying.
[0058] In some embodiments of the present invention, ensuring the stability of the foundation includes: ① understanding the geological conditions and assessing the bearing capacity and stability of the foundation; ② selecting a rock foundation or concrete foundation to avoid unstable areas; ③ setting permanent markers, ensuring that the markers are firmly bonded to the foundation, and taking protective measures; ④ reinforcing foundations that meet the requirements to improve their stability; ⑤ regularly checking the stability of the foundation, monitoring the displacement of control points, and promptly repairing any problems; ⑥ recording the foundation conditions and inspection results, and promptly reporting any abnormalities.
[0059] In some embodiments of the present invention, step S3 includes: S3.1. Multiple first traverse points are set up along the centerline of the tunnel, and multiple second traverse points are set up along one side of the tunnel. The first traverse points and the second traverse points are set up in a one-to-one correspondence to form the main control network of the cross traverse.
[0060] S3.2 Using the baseline control points of the traverse as elevation control points, a pair of the elevation control points are set up every 100m inside the tunnel.
[0061] S3.3. Using traverse points that are close to the tunnel entrance and have good visibility, use a total station to backsight other traverse points and measure the azimuth angles from each traverse point to the tunnel entrance traverse point. Take the average value as the azimuth angle of the traverse reference point from the tunnel entrance traverse point.
[0062] S3.4. Based on the main control network of the cross traverse, a total station is used to perform precise traverse surveying, and the control network inside the tunnel is adjusted and the centerline is adjusted to complete the centerline measurement inside the tunnel.
[0063] S3.5. Two leveling points are set up at the tunnel entrance. Based on the leveling points, a level instrument is used to conduct precise leveling point measurement. Then, the elevation control point is observed back and forth to ensure that the observation limit and accuracy meet the specified accuracy requirements, so as to complete the elevation measurement inside the tunnel.
[0064] In some possible embodiments, in step S3, the accuracy is ensured by designing using planar control measurements, as follows: Before tunnel breakthrough, horizontal control surveying inside the tunnel is conducted using a single-sided traverse. When tunnel excavation begins, the traverse must first be designed based on the excavation length of the tunnel chambers (either facing or unidirectional) and the design breakthrough accuracy requirements. This involves estimating the expected error and determining the traverse surveying level to ensure the accuracy of the tunnel excavation axis, i.e., breakthrough accuracy, and to select surveying equipment and methods in a more reasonable and economical manner.
[0065] Then, based on the tunnel design excavation drawings, draw the tunnel excavation plan and the location of the breakthrough face on CAD or paper at a certain scale. Take into full account the measurement environment inside the tunnel during excavation (such as the influence of visibility conditions and muck removal on measurement) and the improvement of measurement accuracy, reasonably select the location of the traverse points, and display them on the drawing.
[0066] The endpoint of the traverse is the weakest point in traverse accuracy. The lateral breakthrough error is caused by the traverse angle measurement error and the traverse side length error. The lateral breakthrough error primarily affects the tunnel breakthrough accuracy. The following analysis focuses on the lateral breakthrough error. According to the error propagation law, traverse angle measurement and side length measurement are two independent quantities. Therefore, the lateral breakthrough error M caused by the traverse angle measurement error can be obtained as follows: (Formula 1); In the formula: = (Formula 2); In the formula: = (Formula 3); In the formula: The lateral mean square error (mm) caused by the angle measurement error on the through surface. In the formula: The lateral mean square error (mm) caused by the side measurement error on the through surface. In the formula: The angle measurement error (″) designed for the control network; In the formula: The vertical distance (m) from each point of the control network to the through surface; In the formula: Design the relative mean square error of the side lengths for the control network; In the formula: The length (m) of the projection of each side of the control net onto the through surface.
[0067] Measure the vertical distance from each point of the control network to the connecting surface on the drawn sketch. The projected lengths of each side of the control network on the through plane Then, based on the accuracy of the instruments and equipment used in this project, determine the angular measurement error of the control network design. Relative mean square error of control network design side length Substituting the values into the above formula, if M is less than the allowable error for lateral tunnel breakthrough, the tunnel can proceed. Otherwise, instruments and equipment meeting the accuracy requirements should be selected, or the route and measurement scheme adjusted, and the calculation repeated until the breakthrough accuracy requirements are met. Furthermore, the measurement should be conducted strictly according to the determined grade technical requirements to guide the excavation of the tunnel's opening position.
[0068] In step S3, on the other hand, the design is carried out through elevation control measurements to ensure its accuracy, as follows: The accuracy of the control measurement of the tunnel's internal elevation directly affects the vertical breakthrough error. The level of elevation control measurement is usually determined based on the vertical breakthrough error caused by leveling.
[0069] (Formula 4); In the formula: = (Formula 5); In the formula: This represents the vertical penetration error; In the formula: The random error per kilometer of leveling measurement (mm); In the formula: L is the total length (km) of the elevation measurement route inside the tunnel; specifically, L can be measured according to the route planned on the map or taken as 3 to 4 times the length of the tunnel axis.
[0070] After determining the level of elevation measurement, select a measurement method that is convenient to implement, economical and reasonable, and can ensure the accuracy of elevation transfer, and carry out the measurement according to the corresponding technical requirements.
[0071] In some embodiments of the present invention, step S4 includes: S4.1 Set the total station at the centerline point inside the tunnel to determine the center of the tunnel face arch, and determine the excavation section based on the center of the tunnel face arch.
[0072] S4.2 After the excavation is completed, the excavation cross-section is inspected using a cross-section measuring instrument. Once the requirements are met, the position of the steel support is precisely determined using a total station to ensure the accuracy of the tunnel centerline and elevation.
[0073] S4.3 Before the lining trolley is in place, the centerline is laid out and the elevation is measured for the lining section. After the lining trolley is in place, the position and structural dimensions of the trolley are checked by plumb line and measuring tape using the laid-out centerline and elevation points. After the lining construction is completed, the centerline and elevation of the lining section are checked, and the net cross-section after lining is measured.
[0074] S4.4. The excavation face advances forward, and construction guide lines are laid out to guide the excavation layout.
[0075] It should be noted that as the excavation face advances, a construction traverse is laid out. The side length of the traverse is 150m to 250m in the straight section of the tunnel and 60m to 100m in the curved section. The construction traverse is used to guide the excavation layout. When excavation progresses every 200m to 300m, a portion of the construction traverse is selected, and a basic traverse with a high accuracy of not less than 200m is laid. The basic traverse is used to check whether the direction of the tunnel is consistent with the design, so as to reduce the transmission and accumulation of measurement errors.
[0076] In some embodiments of the present invention, step S5 includes: S5.1 At the tunnel breakthrough face, the plane coordinates of the breakthrough point are determined from both ends of the tunnel using the coordinate method, and the measurement results are transferred to the breakthrough cross section and centerline to calculate the transverse breakthrough error and the longitudinal breakthrough error.
[0077] S5.2 After the tunnel is completed, the elevation of the breakthrough point is determined from both ends of the tunnel using leveling. The difference between the elevations is the vertical breakthrough error.
[0078] S5.3. Adjust the underground traverse as a traverse and adjust the centerline points of the line according to the adjusted coordinate values; adjust the underground leveling line as a traverse and take the average elevation of the connection points measured at both ends as the adjusted elevation value.
[0079] S5.4. Use the adjusted centerline point coordinates and adjusted elevation values as the starting data for the final clearance measurement and line adjustment. Use a laser profiler or total station to measure the tunnel clearance cross-section and check whether the position of the line and structure meets the design requirements.
[0080] Specifically, when determining the plane coordinates of the traverse point using the coordinate method, the total station is fixed to the observation pier at the traverse point using a forced centering device. This device, made of stainless steel, is fixed to the top of the concrete observation pier by pre-embedded bolts, and its top has a standard threaded interface for connection to the total station base. During leveling, the level instrument is set at the measurement point using a support, with pointed feet on the support legs for stability. Temporary measurement markers are set at the traverse point location; these markers are made of aluminum alloy and have magnetic bases at the bottom that attach to the steel support of the traverse surface. During traverse adjustment, the measurement data is input into the calculation equipment, and the least squares method is used for adjustment calculations. Adjustable measurement markers are used for adjusting the centerline points of the route. These markers are set on the tunnel lining surface via sliding bases, which are fixed by expansion bolts, allowing for fine-tuning of the marker's position within the plane.
[0081] After the tunnel is completed, a total station is first set up at the traverse points on both sides of the breakthrough face, and the plane coordinates of the breakthrough points are measured from both ends of the tunnel. The measurement results are then converted to the breakthrough cross-section and centerline direction to calculate the lateral and longitudinal breakthrough errors. Simultaneously, a level is used to determine the elevation of the breakthrough points from both ends of the tunnel to calculate the vertical breakthrough error. The underground traverse is used as a traverse for adjustment calculations, and the position of the centerline point is adjusted based on the adjusted coordinate values. The underground level is used as a traverse for adjustment, and the average elevation measured at both ends is taken as the final elevation of the breakthrough point. The adjusted coordinates and elevation results are used as the starting data for clearance measurement and centerline adjustment.
[0082] This embodiment provides conditions for cross-checking measurement data by measuring the coordinates and elevations of the breakthrough point from both ends of the tunnel; it eliminates the accumulation of measurement errors and improves the accuracy of coordinate adjustment by using a traverse and adjustment calculation method; and it reduces the influence of single-end measurement errors by taking the average elevation, ensuring the reliability of elevation adjustment. Beneficial effects include: the bidirectional measurement method ensures the accuracy of breakthrough error determination; rigorous adjustment calculations improve the accuracy of the resulting data; and the adjusted measurement results provide a reliable benchmark for subsequent clearance measurement and centerline adjustment, ensuring that the tunnel breakthrough quality meets design requirements. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A tunnel construction surveying method, characterized in that, include: S1. Before tunnel construction, design control measurements inside the tunnel based on the propagation law of measurement errors; S2. Set up horizontal and vertical control points near the tunnel entrance and conduct entrance control measurements; S3. Lay out a cross-traverse main control network inside the tunnel, and conduct control measurements inside the tunnel based on the cross-traverse main control network laid out inside the tunnel. S4. Using a total station to measure the traverse line inside the tunnel, the tunnel construction layout is carried out; S5. After the tunnel is completed, the breakthrough error is measured and adjusted.
2. The tunnel construction surveying method according to claim 1, characterized in that, The tunnel control and measurement design includes: Based on the requirements for tunnel length, shape, and breakthrough accuracy, a mathematical model of the traverse network is established to simulate the error propagation path; The least squares method is used to perform adjustment calculations on the survey network, thereby optimizing the layout of traverse points and the level of measurement accuracy. Determine the accuracy level and implementation plan for horizontal control surveying and vertical control surveying.
3. The tunnel construction surveying method according to claim 1, characterized in that, The portal control measurement includes: At least three plane control points are set up near the tunnel entrance to ensure that the plane control points can cover the tunnel entrance area, and the distance between adjacent plane control points is 200m to 500m; At least two elevation control points are set up near the tunnel entrance, and the elevation control points are shared with the horizontal control points or set up separately; Ensure that the plane control points and the elevation control points are mutually visible, that the foundations on which the plane control points and the elevation control points are located are stable, and that they are visible to the excavated opening. GPS combined with a total station was used to conduct control measurements outside the tunnel, and joint measurements were carried out with control points of adjacent roadbeds or bridges.
4. The tunnel construction surveying method according to claim 3, characterized in that, Ensuring that the horizontal control point and the vertical control point are mutually visible includes: The horizontal control points and the vertical control points are set up in locations with high terrain and open views. The visibility between the horizontal control points and the vertical control points shall be checked visually and with the aid of tools. Clear vegetation between the horizontal control point and the vertical control point, remove buildings or temporary facilities, and ensure unobstructed visibility between the horizontal control point and the vertical control point; Adjust the positions of the plane control points and the elevation control points or add plane control points and elevation control points according to the visibility requirements; Use measuring instruments to retest the visibility and record the visibility status; Regularly inspect and promptly remove any new obstacles to ensure visibility.
5. The tunnel construction surveying method according to claim 3, characterized in that, The stability of the foundation where the horizontal control points and the vertical control points are located is ensured by the following methods: Understand the geological conditions of the foundation where the plane control points and the elevation control points are located, assess the bearing capacity and stability of the foundation, and select a rock foundation or a concrete foundation. Install permanent markers, ensure that the markers are firmly bonded to the foundation, and reinforce the foundation. Regularly monitor the displacement of the horizontal control points and the vertical control points, and record and report any abnormalities.
6. The tunnel construction surveying method according to claim 1, characterized in that, The control measurements inside the tunnel include: Multiple first traverse points are set up along the centerline of the tunnel, and multiple second traverse points are set up along one side of the tunnel. The first traverse points and the second traverse points are set up in a one-to-one correspondence to form the main control network of the intersecting traverses. Using the baseline control points of the traverse as elevation control points, a pair of these elevation control points are set up every 100m inside the tunnel; Using traverse points that are close to the tunnel entrance and have good visibility, the total station is used to backsight other traverse points. The azimuth angles from each traverse point to the tunnel entrance traverse point are measured, and the average value is taken as the azimuth angle from the traverse reference point to the tunnel entrance traverse point. Based on the aforementioned cross-traverse main control network, a total station is used to conduct precise traverse surveys, and the control network adjustment and centerline adjustment within the tunnel are carried out to complete the centerline measurement within the tunnel. Two leveling points are set up at the tunnel entrance. Based on these leveling points, a level instrument is used to conduct precise leveling measurements. Then, the elevation control points are observed back and forth to ensure that the observation limits and accuracy meet the specified accuracy requirements, so as to complete the elevation measurement inside the tunnel.
7. The tunnel construction surveying method according to claim 1, characterized in that, The use of a total station for traverse surveying within the tunnel for tunnel construction layout includes: Set the total station at the centerline point inside the tunnel to determine the center of the tunnel face arch, and determine the excavation section based on the center of the tunnel face arch. After the excavation is completed, a cross-section inspection instrument is used to check the excavation cross-section. Once the requirements are met, a total station is used to accurately determine the position of the steel support to ensure the accuracy of the tunnel centerline and elevation. Before the lining trolley is in place, the centerline is laid out and the elevation is measured for the lining section. After the lining trolley is in place, the position and structural dimensions of the trolley are checked by plumb line and measuring tape using the laid-out centerline and elevation points. After the lining construction is completed, the centerline and elevation of the lining section are checked, and the net cross-section after lining is measured. The excavation proceeds forward, and construction guide lines are laid out to guide the excavation layout.
8. The tunnel construction surveying method according to claim 7, characterized in that, As the excavation face advances forward, the side length of the construction guide is 150m to 250m in the straight section of the tunnel and 60m to 100m in the curved section. Every 200m to 300m of tunneling, a section of the construction traverse is selected, and a basic traverse of not less than 200m is laid. The basic traverse is used to check whether the direction of the tunnel is consistent with the design, so as to reduce the transmission and accumulation of measurement errors.
9. The tunnel construction surveying method according to claim 1, characterized in that, After the tunnel is completed, the measurement and adjustment of the breakthrough error includes: At the tunnel breakthrough face, the coordinate method is used to determine the plane coordinates of the breakthrough point from both ends of the tunnel, and the measurement results are converted to the breakthrough section and centerline to calculate the transverse breakthrough error and the longitudinal breakthrough error. After the tunnel is completed, leveling is used to determine the elevation of the breakthrough point from both ends of the tunnel, and the difference is the vertical breakthrough error. The completed underground traverse is used as a traverse for adjustment, and the centerline point of the line is adjusted according to the adjusted coordinate values; the completed underground leveling line is used as a traverse for adjustment, and the average elevation of the connection point measured at both ends is taken as the adjusted elevation value. The adjusted centerline coordinates and elevation values are used as the starting data for the final clearance measurement and line adjustment. A laser profiler or total station is used to measure the tunnel clearance profile to check whether the position of the line and structure meets the design requirements.