A measurement method for controlling overbreak and underbreak of a folded line tunnel with high precision

Abstract

The application provides a kind of broken line tunnel high-precision control underbreak measurement method, steps are as follows: (1) respectively determine the start and end mileage points of S1, S2 section turning and S2, S3 section turning of tunnel; (2) for each section of tunnel, according to the corresponding tunnel edge line, respectively determine the left side tunnel calculation center line and the right side tunnel calculation center line; (3) according to the tunnel section corresponding to the original tunnel center line of the section of tunnel, respectively determine the left and right sides of the calculation center line belonging to the section; (4) calculate the three-dimensional coordinates of any tunnel contour point within two sections of mileage through the calculation center line and the section belonging to it; (5) through the three-dimensional coordinates of any contour point at the corresponding mileage, loft the contour to the tunnel excavation face, and excavate according to the lofting point position. The application accurately calculates the tunnel contour coordinates at the turning point of broken line tunnel by simulating the tunnel "calculation center line", improves the measurement accuracy, ensures the tunnel limit requirement, and improves the work efficiency.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a high-precision measurement method for controlling over-excavation and under-excavation in a polygonal tunnel. Background Technology

[0002] During tunnel excavation, in order to control over-excavation and under-excavation with high precision, it is usually necessary to guide the excavation direction and accuracy through precise measurement work, so as to ensure that the tunnel outline meets the service clearance requirements.

[0003] For conventional tunnel routes, they are usually composed of transition curves, circular curves, and straight lines, with the centerline of the tunnel being symmetrical on both sides. However, for some zigzag tunnels with sharp bends, the tunnel profile corresponding to that mileage at the turning point is not actually symmetrical.

[0004] Currently, for the measurement of conventional tunnels, the tunnel cross-sections on both sides of the tunnel centerline corresponding to a certain mileage are perpendicular to the tunnel centerline. The three-dimensional coordinates of the tunnel outline are usually calculated from the tunnel centerline before being laid out. However, for the aforementioned zigzag tunnels with sharp bends, the tunnel cross-sections on both sides corresponding to that mileage are not necessarily perpendicular to the tunnel centerline at the bend, which makes the measurement of this type of tunnel more difficult. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a measurement method for high-precision control of over-excavation and under-excavation in polygonal tunnels.

[0006] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0007] A high-precision measurement method for controlling over-excavation and under-excavation in a polygonal tunnel includes the following steps:

[0008] (1) Along the excavation direction, the tunnel sections connected in sequence are named S1, S2 and S3 sections respectively;

[0009] At the junction of sections S1 and S2, taking point O, the turning point of the excavation outline on the left side of the tunnel centerline, as the base point, draw perpendicular lines to the tunnel centerlines of sections S1 and S2, respectively, intersecting the centerline at points a and b, respectively; at the same time, extend the above perpendicular lines and intersect the excavation outline on the right side of the tunnel centerline at points c and d, respectively; the turning point j of the excavation outline on the left side of the tunnel centerline is located between points c and d.

[0010] At the junction of sections S2 and S3, taking the turning point e of the excavation outline on the left side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline, intersecting at point g. Extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point h. Taking the turning point i of the excavation outline on the right side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline, intersecting at point h. Extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point f.

[0011] Points a and b are the starting and ending mileage points of the turning points of tunnel sections S1 and S2, respectively; points g and h are the starting and ending mileage points of the turning points of tunnel sections S2 and S3, respectively; further calculations will be performed for tunnels within these two mileage segments.

[0012] (2) For tunnels in the ab section: take the right side line of the tunnel cj and jd as the reference, and offset the tunnel radius of the tunnel section as the offset distance to obtain the calculated center line of the right tunnel; the tunnel side line on the left side of the tunnel is a point, and the calculated center line of the left tunnel at this time is the actual tunnel center line.

[0013] For tunnels in the gh section: using the left edge line ef as the reference, offset by the tunnel radius of the tunnel cross section to obtain the "calculated center line" of the left tunnel; using the right edge line hi of the tunnel center line as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line of the right tunnel.

[0014] (3) Determine the cross sections on the left and right sides of the calculated center line based on the tunnel cross sections corresponding to the original tunnel center lines of the ab and gh sections.

[0015] (4) Since the tunnel cross sections on both sides of the tunnel centerline are perpendicular to the calculation centerline, after determining all the calculation centerlines and their respective cross sections of the two tunnels, the three-dimensional coordinates of any contour point corresponding to any mileage within the two mileages can be calculated through the calculation centerlines and their respective cross sections.

[0016] (5) Using the three-dimensional coordinates of any contour point at the corresponding mileage obtained by calculation, the tunnel contour is laid out onto the tunnel excavation face, and excavation is carried out according to the laid-out points.

[0017] As one of the preferred embodiments of the present invention, in step (1), the mileage between points a and b of the tunnel and the mileage between points g and h are calculated in the next step; the tunnels outside these two mileage sections are measured and laid out using conventional methods.

[0018] As one of the preferred embodiments of the present invention, the use of conventional methods for measurement and layout refers to: directly laying out the tunnel by controlling the centerline and cross-sectional profile, without the need to introduce a calculated centerline.

[0019] As one of the preferred embodiments of the present invention, in step (2), for the tunnel of mileage ab: taking the right side line cj, jd of the tunnel as the reference, and the tunnel radius of the tunnel cross section as the offset distance, the calculated center lines aj', j”b are obtained; taking the left side line of the tunnel as a point, the tunnel center lines ak, kb are taken as the reference, and the vertical distance between the tunnel center line and the tunnel side line is taken as the offset distance, the calculated tunnel side lines ok', k”o are obtained, and the calculated center line at this time is the actual tunnel center line;

[0020] For tunnels in the gh section: using the left side line ef of the tunnel as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line e'f' of the left tunnel; using the right side line hi of the tunnel center line as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line h'i' of the right tunnel.

[0021] As one of the preferred embodiments of the present invention, in step (3), for the tunnel of mileage ab: the tunnel cross section to the left of the center line aj', j”b is calculated as cross section S1, and the tunnel cross section to the right of the actual tunnel center line ak, kb is cross section S1.

[0022] For tunnels in the gh section: the tunnel cross-section to the left of the tunnel calculation centerline e'f' is the S3 cross-section, and the tunnel cross-section to the right of the tunnel calculation centerline h'i' is the S3 cross-section.

[0023] As one of the preferred embodiments of the present invention, in step (4), for the tunnel of mileage gh, the three-dimensional coordinates of the corresponding mileage contour are obtained by the following specific method:

[0024] ① To calculate the contour coordinates of point DKXXX within the gh segment, first determine the azimuth angles α1 and α2 of the calculation center lines e'f' and h'i' respectively;

[0025] Regarding the azimuth angle α1 of the tunnel centerline e'f', o is first calculated using the following formula:

[0026] o = arctan(y1-y2) / (x1-x2);

[0027] In the formula, x1 and y1 are the x and y coordinates of e', respectively, and x2 and y2 are the x and y coordinates of f', respectively;

[0028] In a coordinate system with x as the horizontal axis and y as the vertical axis: if o is in the first quadrant, the azimuth angle α1 = o;

[0029] If o is in the second quadrant, the azimuth angle α1 = 180° - o; if o is in the third quadrant, α1 = 180° + o; if o is in the fourth quadrant, α1 = 360° - o.

[0030] The azimuth angle α2 of the centerline h'i' is calculated using the same method;

[0031] ② Obtain the tunnel center coordinates O1(x1, y1, z1) and O2(x2, y2, z2) on the calculated center lines e'f' and h'i' corresponding to the tunnel at mileage DKXXX from the tunnel plan view, where z is obtained by designing the tunnel cross section;

[0032] ③ Calculate the coordinates of any point on the tunnel profile within this mileage using the tunnel center coordinates and azimuth angle;

[0033] Calculate the coordinates of any contour point on the left side of the tunnel: Using the tunnel center coordinates O1(x1, y1, z1) and azimuth angle α1, calculate the coordinates A of any contour point on the left side of the tunnel at this mileage. 左 (x a y a , z a );in:

[0034] x a =x1 + B·cosα1;

[0035] y a =y1+B·sinα1;

[0036] z a =z1+H;

[0037] B 左 —Corresponding cross-sectional profile point A 左 Offset corresponding to the tunnel centerline;

[0038] H 左 —Corresponding cross-sectional profile point A 左 The relative elevation of the tunnel centerline;

[0039] Coordinates of any contour point on the right side of the tunnel: Calculate the coordinates A of any contour point on the right side of the tunnel at this mileage using the tunnel center coordinates O2(x2, y2, z2) and azimuth angle α2. 右 (x a y a , z a The method is the same as above;

[0040] Based on the above A 左 (x a y a , z a A) 右 (x a y a , z a ), to obtain the three-dimensional coordinates (x, y, z) of any contour point of the tunnel in the gh section.

[0041] As one of the preferred embodiments of the present invention, in step (4), the method for obtaining the three-dimensional coordinates of the contour within the mileage segment ab is the same as that for the mileage segment gh.

[0042] As one of the preferred embodiments of the present invention, in step (5), the three-dimensional coordinates of any contour point at the corresponding mileage are obtained by calculation using a total station, and the tunnel contour is laid out on the tunnel excavation face. Excavation is carried out according to the laid-out points to ensure that the tunnel clearance at that mileage meets the design requirements.

[0043] The advantages of this invention compared to the prior art are as follows: This invention overcomes the difficulties of asymmetrical cross-sections on both sides of the tunnel centerline at the turning point of a polygonal tunnel, which leads to high measurement difficulty and poor accuracy. By simulating the tunnel's "calculation centerline," the invention accurately calculates the tunnel outline coordinates at the turning point of the polygonal tunnel, thereby improving tunnel measurement accuracy, ensuring tunnel clearance requirements, and increasing work efficiency. Attached Figure Description

[0044] Figure 1 This is a plan view of the tunnel and the starting and ending mileage points of the turning lines of each section above it in Example 1;

[0045] Figure 2 This is a plan view of the calculated centerline of the right tunnel in the ab section of Example 1 (in the figure, Figure 2 'a' is the calculation centerline aj'. Figure 2 b is the calculation centerline j”b);

[0046] Figure 3 This is a plan view of the calculated centerline of the left tunnel in the ab section of Example 1 (in the figure, Figure 3 'a' represents the calculated centerline corresponding to the calculated tunnel edge line 'ok'. Figure 3 b is the calculation centerline corresponding to the calculated tunnel edge line k”o;

[0047] Figure 4 This is a plan view of the calculated centerline of the tunnel in section gh of Example 1 (in the figure, Figure 4 a is the calculated centerline e'f' of the left tunnel. Figure 4 b is the calculated centerline h'i' of the right-side tunnel;

[0048] Figure 5 This is a plan view of the location of DKXXX within the tunnel gh section of Example 1;

[0049] Figure 6 This is a schematic diagram of the calculated centerline at location DKXXX in the tunnel in Example 1;

[0050] Figure 7 This is a schematic diagram of the cross-section at mileage DKXXX in Example 1. Detailed Implementation

[0051] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0052] Example 1

[0053] This embodiment of a high-precision measurement method for over- and under-excavation control in a polygonal tunnel includes the following steps:

[0054] (1) Determine the starting and ending mileage points of the tunnel section turning (refer to...) Figure 1 ):

[0055] ① Along the excavation direction, the tunnel sections connected in sequence are named S1, S2, and S3 sections respectively.

[0056] ② At the junction of sections S1 and S2, taking point O, the turning point of the excavation outline on the left side of the tunnel centerline, as the base point, draw perpendicular lines to the tunnel centerlines of sections S1 and S2, respectively, intersecting the centerlines at points a and b, respectively; at the same time, extend the above perpendicular lines and intersect the excavation outline on the right side of the tunnel centerline at points c and d, respectively; the turning point j of the excavation outline on the left side of the tunnel centerline is located between points c and d.

[0057] ③ At the turning point between sections S2 and S3, take the turning point e of the excavation outline on the left side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline intersecting at point g, and extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point h. Take the turning point i of the excavation outline on the right side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline intersecting at point h, and extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point f.

[0058] ④ Through the above steps, points a and b can be determined as the starting and ending mileage points of the turns in tunnel sections S1 and S2, respectively, and points g and h are the starting and ending mileage points of the turns in sections S2 and S3, respectively. Based on this, the next step of calculation is carried out for tunnels within these two mileage segments, while tunnels outside these two mileage segments are calculated and laid out using conventional methods (laying out by controlling the tunnel centerline and cross-sectional profile).

[0059] (2) At tunnel bends, some tunnel edges are not parallel to the tunnel centerline. The calculated centerline of the tunnel is determined by the tunnel edges on the left and right sides of the tunnel centerline:

[0060] ① For tunnels in mileage section ab: refer to Figure 2 a, 2b, using the right side line cj, jd of the tunnel as the reference, and offsetting by the tunnel radius of the tunnel cross-section, the calculated center lines aj', j”b are obtained; refer to Figure 3a, 3b, the tunnel edge on the left side of the tunnel is taken as a point. Then, the tunnel centerline ak, kb is used as the reference, and the vertical distance between the tunnel centerline and the tunnel edge is used as the offset to obtain the calculated tunnel edgeline ok', k”o. The calculated centerline at this time is the actual tunnel centerline.

[0061] ② For tunnels in the gh section: refer to Figure 4 a, 4b, Using the left side line ef of the tunnel as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line e'f' of the left tunnel; using the right side line hi of the tunnel center line as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line h'i' of the right tunnel.

[0062] (3) Determine the cross-sections corresponding to the original tunnel centerline based on the mileage of the ab and gh segments:

[0063] ① For tunnels in the ab section: the tunnel cross-section to the left of the calculated centerline aj', j”b is the S1 cross-section, and the tunnel cross-section to the right of the actual tunnel centerline ak, kb is the S1 cross-section.

[0064] ② For tunnels in the gh section: the tunnel cross-section to the left of the tunnel calculation centerline e'f' is the S3 cross-section, and the tunnel cross-section to the right of the tunnel calculation centerline h'i' is the S3 cross-section.

[0065] (4) Since the tunnel cross-sections on both sides of the tunnel centerline are perpendicular to the calculation centerline, after determining all the calculation centerlines and their respective cross-sections for the two tunnel segments, the three-dimensional coordinates of any contour point corresponding to any mileage within the two segments can be calculated using the calculation centerlines and their respective cross-sections:

[0066] The location of DKXXX within the gh section is as follows: Figure 5 As shown, taking the calculation of the contour coordinates of point DKXXX within the gh segment as an example:

[0067] ① First, determine the azimuth angles α1 and α2 of the calculation centerlines e'f' and h'i' respectively, refer to Figure 6 ( Figure 6 This is a plan view; azimuth angles α1 and α2 are not shown in the diagram.

[0068] Regarding the azimuth angle α1 of the tunnel centerline e'f', o is first calculated using the following formula:

[0069] o = arctan(y1-y2) / (x1-x2);

[0070] In the formula, x1 and y1 are the x and y coordinates of e', respectively, and x2 and y2 are the x and y coordinates of f', respectively;

[0071] In a coordinate system with x as the horizontal axis and y as the vertical axis: if o is in the first quadrant, the azimuth angle α1 = o;

[0072] If o is in the second quadrant, the azimuth angle α1 = 180° - o; if o is in the third quadrant, α1 = 180° + o; if o is in the fourth quadrant, α1 = 360° - o.

[0073] The azimuth angle α2 of the centerline h'i' is calculated using the same method.

[0074] ② Obtain the tunnel center coordinates O1(x1, y1, z1) and O2(x2, y2, z2) on the calculation center lines e'f' and h'i' corresponding to the tunnel mileage DKXXX from the tunnel plan, where z is obtained by designing the tunnel cross section.

[0075] ③See reference Figure 7 The coordinates of any point on the tunnel profile within this mileage are calculated using the tunnel center coordinates and azimuth.

[0076] Calculate the coordinates of any contour point on the left side of the tunnel: Using the tunnel center coordinates O1(x1, y1, z1) and azimuth angle α1, calculate the coordinates A of any contour point on the left side of the tunnel at this mileage. 左 (x a y a , z a );in:

[0077] x a =x1 + B·cosα1;

[0078] y a =y1+B·sinα1;

[0079] z a =z1+H;

[0080] B 左 —Corresponding cross-sectional profile point A 左 Offset corresponding to the tunnel centerline;

[0081] H 左 —Corresponding cross-sectional profile point A 左 The relative elevation of the tunnel centerline.

[0082] Coordinates of any contour point on the right side of the tunnel: Calculate the coordinates A of any contour point on the right side of the tunnel at this mileage using the tunnel center coordinates O2(x2, y2, z2) and azimuth angle α2. 右 (x a y a , z a The method is the same as above, where the corresponding cross-sectional profile point A 右 The offset corresponding to the tunnel centerline is B 右Corresponding to section profile point A 右 The relative elevation of the tunnel centerline is H 右 .

[0083] Based on the above A 左 (x a y a , z a A) 右 (x a y a , z a ), to obtain the three-dimensional coordinates (x, y, z) of any contour point of the tunnel in the gh section.

[0084] The method for obtaining the three-dimensional coordinates of the inner contour of segment ab is the same as that for segment gh.

[0085] (5) Using a total station, the three-dimensional coordinates of any contour point at the corresponding mileage are obtained by calculation. The tunnel contour is then laid out onto the tunnel excavation face. Excavation is carried out according to the laid-out points to ensure that the tunnel clearance at that mileage meets the design requirements.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision measurement method for controlling over-excavation and under-excavation in a polygonal tunnel, characterized in that, Includes the following steps: (1) Along the excavation direction, the tunnel sections connected in sequence are named S1, S2 and S3 sections respectively; At the junction of sections S1 and S2, taking point O, the turning point of the excavation outline on the left side of the tunnel centerline, as the base point, draw perpendicular lines to the tunnel centerlines of sections S1 and S2, respectively, intersecting the centerline at points a and b, respectively; at the same time, extend the above perpendicular lines and intersect the excavation outline on the right side of the tunnel centerline at points c and d, respectively; the turning point j of the excavation outline on the left side of the tunnel centerline is located between points c and d. At the junction of sections S2 and S3, taking the turning point e of the excavation outline on the left side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline, intersecting at point g. Extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point h. Taking the turning point i of the excavation outline on the right side of the tunnel centerline as the base point, draw a perpendicular line to the tunnel centerline, intersecting at point h. Extend the perpendicular line to intersect the outline on the right side of the tunnel centerline at point f. Points a and b are the starting and ending mileage points of the turning points of tunnel sections S1 and S2, respectively; points g and h are the starting and ending mileage points of the turning points of tunnel sections S2 and S3, respectively; further calculations will be performed for tunnels within these two mileage segments. (2) For tunnels in the ab section: take the right side line cj and jd of the tunnel as the reference, and offset the tunnel radius of the tunnel section as the offset distance to obtain the calculated center line of the right tunnel; the tunnel side line on the left side of the tunnel is a point, and the calculated center line of the left tunnel at this time is the actual tunnel center line. For tunnels in the gh section: using the left sideline ef as the reference, offset by the tunnel radius of the tunnel cross section to obtain the "calculated centerline" of the left tunnel; Using the right side line hi of the tunnel centerline as a reference, and the tunnel radius of the tunnel cross section as the offset distance, the calculated centerline of the right tunnel is obtained. (3) Determine the cross sections on the left and right sides of the calculated center line based on the tunnel cross sections corresponding to the original tunnel center lines of the ab and gh sections. (4) Since the tunnel cross sections on both sides of the tunnel centerline are perpendicular to the calculation centerline, after all the calculation centerlines and their respective cross sections of the two tunnels are determined, the three-dimensional coordinates of any contour point corresponding to any mileage within the two mileages can be calculated through the calculation centerlines and their respective cross sections. For tunnels within the gh section, the three-dimensional coordinates of the corresponding mileage contour are obtained using the following specific method: Step 1: If you want to calculate the contour coordinates of DKXXX within the gh segment, first determine the azimuth angles α1 and α2 of the calculation center lines e'f' and h'i' respectively. Regarding the azimuth angle α1 of the tunnel centerline e'f', it is first calculated using the following formula. : ； In the formula, , The x and y coordinates of e' are respectively. , Let x and y be the x and y coordinates of f', respectively; In a coordinate system with x as the horizontal axis and y as the vertical axis: if o is in the first quadrant, the azimuth angle α1 = ; If o is in the second quadrant, the azimuth angle α1 = 180° - o; if o is in the third quadrant, α1 = 180° + o; if o is in the fourth quadrant, α1 = 360° - o. The azimuth angle α2 of the centerline h'i' is calculated using the same method; Step 2: Obtain the tunnel center coordinates O1(x1, y1, z1) and O2(x2, y2, z2) on the calculation center lines e'f' and h'i' corresponding to the tunnel at mileage DKXXX in the tunnel plan view, where z is obtained by designing the tunnel cross section; Step 3: Calculate the coordinates of any point on the tunnel profile within this mileage using the tunnel center coordinates and azimuth. Calculate the coordinates of any contour point on the left side of the tunnel: Using the tunnel center coordinates O1(x1, y1, z1) and azimuth angle α1, calculate the coordinates A of any contour point on the left side of the tunnel at this mileage. 左 (x a y a , z a );in: = + B 左 ； = + B 左 ； = + H 左 ； B 左 —Corresponding cross-sectional profile point A 左 Offset corresponding to the tunnel centerline; H 左 —Corresponding cross-sectional profile point A 左 The relative elevation of the tunnel centerline; Coordinates of any contour point on the right side of the tunnel: Calculate the coordinates A of any contour point on the right side of the tunnel at this mileage using the tunnel center coordinates O2(x2, y2, z2) and azimuth angle α2. 右 (x a y a , z a The method is the same as above; Based on the above A 左 (x a y a , z a A) 右 (x a y a , z a ), to obtain the three-dimensional coordinates (x, y, z) of any contour point of the tunnel in the gh section; The method for obtaining the three-dimensional coordinates of the contour within the mileage section ab is the same as that for the mileage section gh. (5) Using the three-dimensional coordinates of any contour point at the corresponding mileage obtained by calculation, the tunnel contour is laid out onto the tunnel excavation face, and excavation is carried out according to the layout points.

2. The measurement method for high-precision control of over-excavation and under-excavation in a polygonal tunnel according to claim 1, characterized in that, In step (1), the mileage between points a and b of the tunnel and the mileage between points g and h are calculated in the next step; the tunnels outside these two mileages are measured and laid out using the following method: the tunnel centerline and cross-sectional profile are directly laid out without the need to introduce the calculation centerline.

3. The measurement method for high-precision control of over-excavation and under-excavation in a polygonal tunnel according to claim 1, characterized in that, In step (2), for tunnels of mileage ab: using the right side line cj, jd of the tunnel as the reference, and the tunnel radius of the tunnel cross section as the offset distance, the calculated center lines aj', j''b are obtained; the left side line of the tunnel is a point, and the tunnel center lines ak, kb are used as the reference, and the vertical distance between the tunnel center line and the tunnel side line is used as the offset distance, the calculated tunnel side lines ok', k''o are obtained, and the calculated center line at this time is the actual tunnel center line; For tunnels in the gh section: using the left side line ef of the tunnel as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line e'f' of the left tunnel; using the right side line hi of the tunnel center line as the reference, offset by the tunnel radius of the tunnel cross section to obtain the calculated center line h'i' of the right tunnel.

4. The measurement method for high-precision control of over-excavation and under-excavation in a polygonal tunnel according to claim 3, characterized in that, In step (3), for tunnels of mileage ab: calculate the tunnel cross section to the left of center lines aj' and j''b as cross section S1, and the tunnel cross section to the right of actual tunnel center lines ak and kb as cross section S1. For tunnels in the gh section: the tunnel cross-section to the left of the tunnel calculation centerline e'f' is the S3 cross-section, and the tunnel cross-section to the right of the tunnel calculation centerline h'i' is the S3 cross-section.

5. The measurement method for high-precision control of over-excavation and under-excavation in a polygonal tunnel according to claim 1, characterized in that, In step (5), the three-dimensional coordinates of any contour point at the corresponding mileage are obtained by calculation using a total station, and the tunnel contour is laid out on the tunnel excavation face. Excavation is carried out according to the laid-out points to ensure that the tunnel clearance at that mileage meets the design requirements.

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