Three-level measurement rechecking method for plane in extra-long railway tunnel hole

Abstract

The invention discloses an extra-long railway tunnel in-hole plane three-level measurement rechecking method, which belongs to the technical field of tunnel measurement and comprises the following steps of: arranging a hole control network on the outer side of a tunnel hole; judging whether the tunneling extension area meets the condition of newly arranging a to-be-encrypted control point in the tunnel or not; performing primary measurement on a to-be-encrypted control point in the hole; judging whether a secondary measurement area can be constructed in the tunneling extension area or not; performing secondary measurement on known control points in a plurality of groups of holes in the secondary measurement area; judging whether the tunneling extension area can be subjected to third-level measurement or not; and performing three-stage measurement on the whole tunneling area. The three-level measurement re-checking method for the plane in the extra-long railway tunnel can adapt to re-checking of control networks in different tunnels, measurement work of the plane control networks in the tunnel can be conducted in a hierarchical, main-body and multi-period mode in the tunneling process, the measurement work can be tightly combined with the construction procedure, and on-site implementation operation is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of tunnel measurement technology, specifically relating to a method for verifying three-level planar measurements inside an extra-long railway tunnel. Background Technology

[0002] With the maturation of infrastructure construction technology in my country, the country has accelerated the construction of railways in the challenging mountainous areas of western China in recent years, and the scale of extra-long railway tunnel construction in the country has expanded significantly.

[0003] Long tunnels present a more challenging measurement environment due to the longer distance the internal horizontal control network extends, and the environment is more adversely affected by factors such as high humidity, dust, and high temperatures inside the tunnel, resulting in greater lateral sway of the control network. Therefore, constructing an accurate control network is of great significance for controlling the sway of the tunnel.

[0004] Existing measurement technologies typically employ methods such as breakthrough error estimation, in-tunnel measurement network shaping, or short-side control reinforcement to measure the tunnel control network. However, during tunnel excavation, there are often challenges such as inconsistent existing methods and systems, high construction difficulty, and high measurement accuracy requirements, making it difficult to effectively guide on-site construction. Summary of the Invention

[0005] In response to one or more of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a three-level measurement verification method for the inner plane of an extra-long railway tunnel. It can adapt to the verification of control networks in different tunnels. It can not only carry out layer-by-layer, main-by-main, and multi-cycle measurement of the inner plane control network during the tunneling process, but also can be closely integrated with the construction process, facilitating on-site implementation.

[0006] To achieve the above objectives, this invention provides a method for verifying the three-level planar measurement inside an extra-long railway tunnel, comprising the following steps: S1. Set up a tunnel entrance control network outside the tunnel entrance, start tunnel excavation, and after excavating a preset distance, set up known control points inside the tunnel, and measure the known control points inside the tunnel through the tunnel entrance control network; S2. Excavate the tunnel according to the tunnel design path. After excavating a preset distance, determine whether the tunnel excavation extension area meets the conditions for adding new control points to be densified inside the tunnel. The conditions for adding new control points to be densified inside the tunnel are determined based on the tunnel excavation distance, the air composition inside the tunnel, the air humidity inside the tunnel, and the visibility between the control points to be densified inside the tunnel and their adjacent known control points inside the tunnel. S3. Determine the subsequent process based on the judgment result of S2; if the judgment result is negative, repeat S2; if the judgment result is positive, execute S4. S4. New control points to be densified within the tunnel are added in the area surrounding the tunnel face, and primary measurement is carried out on the control points to be densified within the tunnel; after the primary measurement is completed, the control points to be densified within the tunnel are converted into known control points within the tunnel. S5. Determine whether a secondary measurement area can be constructed within the tunnel excavation extension area; if not, continue excavation and proceed to step S2; if yes, construct a secondary measurement area within the tunnel excavation extension area. The criteria for determining whether the tunnel extension area can constitute a secondary measurement area are: whether the distance of the newly excavated tunnel from the previous secondary measurement area is greater than 1 km, or whether three sets of control points are set up in the newly excavated area from the previous secondary measurement area; as long as at least one of the two conditions is met, secondary measurement can be carried out. S6. Conduct secondary measurements on several sets of known control points inside the tunnel within the secondary measurement area; S7. Determine whether the tunnel excavation extension area can be measured at level 3; if yes, continue excavation and proceed to step S2; if no, perform level 3 measurement on the entire tunnel excavation area. The criteria for determining whether the tunnel extension area can constitute a Level 3 measurement area are: whether the time since the last Level 3 measurement is greater than one year or whether the distance of the new tunnel excavation is greater than 3km; Level 3 measurement can be carried out as long as at least one of the two conditions is met.

[0007] As a further preferred embodiment of the present invention, the primary measurement includes the following steps: Collect the spatial locations of two sets of known control points within the cave that are closest to the location of the control point to be encrypted within the cave. Measure the actual position parameters of the control points to be encrypted within the tunnel relative to the known control points within the tunnel; The first-level measurement of the calculated actual position parameters and standard position parameters is poor; Determine whether the first-level measurement error meets the first-level remeasurement limit; if so, convert the control point to be densified in the tunnel into a known control point in the tunnel and record the first-level measurement coordinates of the known control point in the tunnel; if not, remeasure the control point to be densified and other known control points around it radially, locally or entirely, and update the coordinates of the out-of-limit point after confirming that there are no errors.

[0008] As a further preferred embodiment of the present invention, the first-level measurement error is determined according to the conductor measurement level; The first-order measurement error for tunnel first-class traverse surveying includes a horizontal angle error of no more than 2.3″ and a distance error of no more than 2mD; the first-order measurement error for tunnel second-class traverse surveying includes a horizontal angle error of no more than 2.8″ and a distance error of no more than 2mD; where mD is the distance measurement error of the total station.

[0009] As a further preferred embodiment of the present invention, performing secondary measurements on the entire tunnel excavation area includes the following steps: Collect the spatial locations of the two sets of known control points inside the tunnel that are closest to the secondary measurement area; Using the two sets of known control points inside the tunnel as starting points, the secondary measurement coordinates of several sets of known control points in the secondary measurement area are recalculated. The difference between the secondary measurement coordinates of each group of known control points calculated from the secondary measurement process and the primary measurement coordinates of each group of known control points is calculated. Determine whether the deviation of the secondary measurement meets the tolerance limit of the secondary measurement; if yes, take the average of the results of the primary measurement and the secondary measurement; if no, conduct partial or full remeasurement of the densified control point results of the primary measurement, and update the coordinates of the out-of-limit points after confirming that there are no errors.

[0010] As a further preferred embodiment of the present invention, the secondary measurement error is determined according to the traverse measurement grade; The tolerance limit for the second-level measurement of a first-order traverse survey of a tunnel, including the lateral coordinate tolerance, is 14 dmm; the tolerance limit for the second-level measurement of a second-order traverse survey of a tunnel, including the lateral coordinate tolerance, is 17 dmm. Here, d represents the length from the starting point to the ending point of the re-survey, in km.

[0011] As a further preferred embodiment of the present invention, performing three-level measurements on the entire tunnel excavation area includes the following steps: Measure the location of the control network at the tunnel entrance to ensure its accuracy. Based on the tunnel portal control network, calculate the third-level measurement coordinates of all known control points inside the tunnel relative to the tunnel portal control network; The difference between the tertiary survey coordinates of each group of known control points and the secondary survey coordinates of each group of known control points is calculated when comparing the tertiary survey coordinates. Determine whether the deviation of the third-level measurement meets the third-level measurement limit; if so, take the average of the results of the second-level measurement and the third-level measurement; if not, conduct partial or complete remeasurement of the densified control point results of the second-level measurement, and update the coordinates of the out-of-limit points after confirming that there are no errors.

[0012] As a further preferred embodiment of the present invention, the third-level measurement difference is determined according to the conductor measurement level; The tolerance limit for the third level of traverse surveying in first-order tunnels, including the lateral coordinate tolerance, is 14 dmm; the tolerance limit for the third level of traverse surveying in second-order tunnels, including the lateral coordinate tolerance, is 17 dmm.

[0013] As a further preferred embodiment of the present invention, measuring the position of the control network at the tunnel entrance to ensure the accuracy of the control network position includes the following steps: Calculate the theoretical horizontal angle and theoretical side length of the backsight control point and the entrance control point outside the tunnel; Measure the horizontal angle and side length of the backsight control point and the entrance control point outside the tunnel; Calculate the difference between the measured horizontal angle and the theoretical horizontal angle, and calculate the difference between the theoretical side length and the measured side length; Determine the limits for horizontal angle difference and side length difference based on the tunnel's measurement grade; Determine whether the difference in horizontal angle and the difference in side length meet the limits for horizontal angle difference and side length difference, respectively. If they both meet the limits, the positions of the tunnel backsight control point and the tunnel entry control point are determined to be stable, and their coordinates can be used as the starting point for the tunnel control network. If one of them does not meet the limit, the tunnel backsight control point and the tunnel entry control point should be remeasured, the unstable points should be identified and their coordinates updated, and the above steps should be repeated.

[0014] As a further preferred embodiment of the present invention, when the measurement grade of the tunnel is special, the limit of the horizontal angle difference is no greater than 2″ and the limit of the side length difference is no greater than 2σmm; when the measurement grade of the tunnel is first, the limit of the horizontal angle difference is no greater than 3″ and the limit of the side length difference is no greater than 2σmm.

[0015] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: The three-level planar measurement verification method for extra-long railway tunnels of this invention is accurate in calculation, stable in control, and widely applicable. By employing three different measurement judgment standards and three different measurement steps corresponding to different tunnel excavation conditions, it can accurately determine the position of control points inside and outside the tunnel during each stage of tunnel excavation, thereby achieving step-by-step control of the lateral sway inside the tunnel and thus accurate control of the lateral breakthrough accuracy of the tunnel. It has good prospects for promotion and application value. Attached Figure Description

[0016] Figure 1 This is a flowchart of the three-level planar measurement and verification method for extra-long railway tunnels in this embodiment of the invention; Figure 2 This refers to the tunnel structure during the first-level measurement in the three-level planar measurement verification method for the interior of an extra-long railway tunnel in this embodiment of the invention. Figure 3 This refers to the tunnel structure during the second-level measurement in the three-level planar measurement verification method for extra-long railway tunnels in this embodiment of the invention. Figure 4 This refers to the tunnel structure during the third-level measurement in the three-level measurement verification method for the interior plane of an extra-long railway tunnel in this embodiment of the invention.

[0017] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Tunnel; 2. Known control points; 3. Control points to be densified; 4. Backsight control points; 5. Tunnel entry control points. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] Example: Please see Figures 1-4 The preferred embodiment of the present invention includes a three-level planar measurement verification method for the interior of an extra-long railway tunnel. Wherein, S1. Set up a tunnel entrance control network outside the designed tunnel entrance of Tunnel 1, start tunnel 1 excavation, and after excavating a preset distance, set up known control points 2 inside the tunnel, and mark the known control points 2 inside the tunnel through the tunnel entrance control network.

[0024] S2. Tunnel 1 is excavated according to the designed path of Tunnel 1. After the preset excavation distance, it is determined whether the extended area of ​​tunnel 1 meets the conditions for adding new control points 3 to be densified inside the tunnel.

[0025] Preferably, the preset tunneling distance is 200m to 400m.

[0026] S3. Determine the subsequent process based on the judgment result of S2; if the judgment result is negative, repeat S2; if the judgment result is positive, execute S4.

[0027] S4. Add new control points 3 to be densified in the tunnel in the area around the tunnel face of tunnel 1, and conduct first-level measurement on control points 3; after completing the first-level measurement, convert control points 3 into known control points 2 in the tunnel.

[0028] S5. Determine whether a secondary measurement area can be constructed in the tunnel 1 excavation extension area; if not, continue excavation and proceed to step S2; if yes, construct a secondary measurement area in the tunnel 1 excavation extension area.

[0029] S6. Conduct secondary measurements on several sets of known control points 2 inside the tunnel in the secondary measurement area.

[0030] S7. Determine whether the tunnel 1 excavation extension area can be measured at level 3; if yes, continue excavation and proceed to step S2; if no, perform level 3 measurement on the entire tunnel 1 excavation area.

[0031] Furthermore, in a preferred embodiment of this application, the tunnel entrance control network includes a rear-view control point group and an entrance control point group.

[0032] The rear-view control point group includes at least one rear-view control point 4, positioned and controlled by GPS or a precise traverse network, used to control the entire travel system of tunnel 1. The entrance control point group includes entrance control points 5 positioned between the rear-view control point 4 and the tunnel entrance. Preferably, the entrance control point group includes two entrance control points 5 arranged laterally between the rear-view control point 4 and the tunnel entrance. More preferably, the projections of the two entrance control points 5 along the extension direction of tunnel 1 both fall within the area of ​​the tunnel entrance, ensuring that the first set of newly added control points within tunnel 1 can determine their spatial location using the entrance control points 5 outside the tunnel entrance. More specifically, the two entrance control points 5 are located on opposite sides of the central axis of tunnel 1.

[0033] Furthermore, in a preferred embodiment of this application, the conditions for adding new control points 3 to be encrypted within the tunnel are determined based on the tunneling distance of tunnel 1, the air composition inside tunnel 1, the air humidity inside tunnel 1, and the visibility between the control point 3 to be encrypted and its adjacent known control point 2 within the tunnel. Preferably, the specific distance between the control point 3 to be encrypted and the known control point 2 within the tunnel along the route direction is 200m to 300m.

[0034] More preferably, in a preferred embodiment of this application, the first-level measurement includes the following steps: Collect the spatial locations of two sets of known control points 2 inside the cave that are closest to the location of the control point 3 to be encrypted inside the cave.

[0035] Measure the actual position parameters of the control point 3 to be encrypted inside the tunnel relative to the known control point 2 inside the tunnel.

[0036] Preferably, the actual location parameters include the horizontal angle and distance of the control point 3 to be encrypted relative to the known control point 2 inside the hole.

[0037] The first-level measurement for calculating actual position parameters and standard position parameters is poor.

[0038] Preferably, the first-order measurement error is determined according to the traverse survey grade. Specifically, the first-order measurement error for the first-order traverse survey grade of Tunnel 1 includes a horizontal angle error of no more than 2.3″ and a distance error of no more than 2mD; the first-order measurement error for the second-order traverse survey grade of Tunnel 1 includes a horizontal angle error of no more than 2.8″ and a distance error of no more than 2mD. Here, 2mD represents the distance measurement error, i.e., the standard error of distance measurement, in mm.

[0039] Determine whether the first-level measurement error meets the first-level remeasurement limit. If yes, convert the control point 3 to be densified in the tunnel into the known control point 2 in the tunnel and record the first-level measurement coordinates of the known control point 2 in the tunnel. If no, remeasure the control point 3 to be densified and other known control points 2 around it radially, locally or entirely. After confirming that there are no errors, update the coordinates of the out-of-limit points.

[0040] Furthermore, in a preferred embodiment of this application, if the control point 3 to be encrypted inside the tunnel is the first set of control points to be encrypted inside the tunnel during the excavation of tunnel 1, then the spatial position of the first set of control points to be encrypted inside the tunnel 3 is determined based on the backsight control point 4 and the entry control point 5. That is, the known control point 2 inside the tunnel in the above steps is replaced with the backsight control point 4 and the entry control point 5, and the other steps are the same.

[0041] Further preferably, in a specific preferred embodiment of this application, in January of a certain year, a new control point 3E / F is added within tunnel 1 to be encrypted. This control point 3E / F is determined by encrypted measurements based on known control points 2A / B and 2C / D within the tunnel, resulting in known control point 2E / F, and the primary measurement coordinates of this known control point 2E / F are recorded. In May of a certain year, after tunnel 1 has advanced 300m, a new control point 3G / H is added within tunnel to be encrypted. This control point 3G / H is determined by encrypted measurements based on known control points 2C / D and 2E / F within the tunnel, resulting in known control point 2G / H, and the primary measurement coordinates of this known control point 2G / H are recorded. In September of a certain year, Tunnel 1 was excavated to a depth of 300m. A new control point 3I / J was added within Tunnel 1 to be densified. This control point 3I / J was determined by further measurements of known control points 2G / H and 2E / F within the tunnel, resulting in the known control point 2I / J. The primary coordinates of the known control point 2I / J were recorded. Subsequently, as Tunnel 1 continued to be excavated, a new control point 3 to be densified could be accurately added within Tunnel 1.

[0042] Furthermore, in a preferred embodiment of this application, the criteria for determining whether the extension area of ​​tunnel 1 can constitute a secondary measurement area are: whether the newly excavated distance of tunnel 1 from the previous secondary measurement area is greater than 1 km, or whether three sets of control points are set up within the newly excavated area of ​​tunnel 1 from the previous secondary measurement area. Secondary measurement can be performed as long as at least one of the two conditions is met.

[0043] More preferably, in the preferred embodiment of this application, the secondary measurement of the entire tunnel 1 excavation area includes the following steps: The spatial locations of the two sets of known control points 2 inside the tunnel that are closest to the secondary measurement area were collected.

[0044] Using the two sets of known control points 2 inside the tunnel as starting points, the secondary measurement coordinates of several sets of known control points 2 in the secondary measurement area are recalculated.

[0045] The difference between the secondary measurement coordinates of each group of known control points 2 calculated based on the secondary measurement process and the primary measurement coordinates of each group of known control points 2 is calculated.

[0046] Preferably, both the primary and secondary measurement coordinates are converted into mileage and offset on the through surface.

[0047] Determine whether the deviation of the secondary measurement meets the tolerance limit of the secondary measurement. If yes, take the average of the results of the primary and secondary measurements. If not, conduct partial or complete remeasurement of the densified control points of the primary measurement, and update the coordinates of the out-of-limit points after confirming that they are correct.

[0048] Preferably, the secondary measurement error is determined according to the traverse survey grade. Specifically, the secondary measurement error for the first-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 14 dmm; the secondary measurement error for the second-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 17 dmm.

[0049] Furthermore, in a specific preferred embodiment of this application, three sets of known control points 2E / F, G / H, and I / J have been arranged within the currently excavated area of ​​tunnel 1. This meets the conditions for conducting secondary measurement. Based on the known control points 2A / B and C / D, known routine calculations are performed to obtain the re-measurement structure of the known control points 2E / F, G / H, and I / J, thus obtaining the secondary measurement coordinates. The primary and secondary measurement coordinates are converted into mileage and deviation, and the secondary measurement difference between the primary and secondary measurement coordinates is calculated. It is determined whether the secondary measurement difference meets the secondary measurement tolerance. If yes, the average of the results of the primary and secondary measurements is taken. If not, partial or complete re-measurement of the densified control points in the secondary measurement area is performed, and the coordinates of the out-of-tolerance points are updated after confirmation.

[0050] Furthermore, in a preferred embodiment of this application, the criteria for determining whether the extension area of ​​tunnel 1 can constitute a level-three measurement area are: whether the time since the last level-three measurement of tunnel 1 is more than one year or whether the distance of the new tunnel excavation of tunnel 1 is more than 3 km. Level-three measurement can be performed as long as at least one of the two conditions is met.

[0051] More preferably, in the preferred embodiment of this application, the three-level measurement of the entire tunnel 1 excavation area includes the following steps: Measure the position of the control network at the outer entrance of Tunnel 1 to ensure the accuracy of the control network position.

[0052] Based on the tunnel entrance control network, calculate the third-level measurement coordinates of all known control points 2 within tunnel 1 relative to the tunnel entrance control network.

[0053] The difference between the tertiary measurement coordinates of each group of known control point 2 and the secondary measurement coordinates of each group of known control point 2 is calculated.

[0054] Preferably, both the secondary and tertiary measurement coordinates are converted into mileage and offset on the through surface.

[0055] Determine whether the deviation of the Level 3 measurement meets the Level 3 measurement tolerance limit. If yes, take the average of the Level 2 and Level 3 measurement results. If no, conduct partial or complete remeasurement of the densified control points of the Level 2 measurement, and update the coordinates of the out-of-limit points after confirming that they are correct.

[0056] Preferably, the third-order measurement error is determined according to the traverse survey grade. Specifically, the third-order measurement error for the first-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 14 dmm; the third-order measurement error for the second-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 17 dmm. d represents the length of the second-order survey area from the starting point to the ending point of the re-survey, i.e., the number of kilometers in the second-order survey area. For example, if the number of kilometers in the second-order survey area is 1 km, then the third-order measurement error for the first-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 14 mm; the third-order measurement error for the second-order traverse survey grade of Tunnel 1 includes a lateral coordinate error limit of 17 mm.

[0057] More specifically, in the preferred embodiment of this application, measuring the position of the control network at the outer entrance of tunnel 1 to ensure the accuracy of the control network position includes the following steps: Calculate the theoretical horizontal angle and theoretical side length of the backsight control point 4 and the entrance control point 5 outside the tunnel; Measure the horizontal angle and side length of the backsight control point 4 and the entrance control point 5 outside the tunnel; Calculate the difference between the measured horizontal angle and the theoretical horizontal angle, and calculate the difference between the theoretical side length and the measured side length; The limits for horizontal angle difference and side length difference are determined based on the measurement level of Tunnel 1; Preferably, when the measurement level of tunnel 1 is Special Grade, the horizontal angle difference limit is no greater than 2″, and the side length difference limit is no greater than 2σmm. When the measurement level of tunnel 1 is First Grade, the horizontal angle difference limit is no greater than 3″, and the side length difference limit is no greater than 2σmm. σmm is the standard deviation of the distance measurement, characterizing the degree of distance dispersion.

[0058] Determine whether the difference in horizontal angle and the difference in side length meet the limits for horizontal angle difference and side length difference, respectively. If they both meet the limits, the positions of the tunnel backsight control point 4 and the tunnel entry control point 5 are determined to be stable, and their coordinates can be used as the starting point for the tunnel control network. If one of them does not meet the limit, the tunnel backsight control point 4 and the tunnel entry control point 5 should be remeasured, the unstable positions should be determined and their coordinates updated, and the above steps should be repeated.

[0059] Furthermore, in a specific preferred embodiment of this application, the external backsight control points 4 are H1 and H2, and the external entry control points 5 are J1 and J2. There are two methods for measuring the horizontal angle and side length of the external backsight control points 4 and the external entry control points 5: The first method calculates ∠H1J1H2, side J1H1, side J1H2 and ∠H1J2H2, side J2H1 and side J2H2 based on the entry point; The second method calculates ∠J1H1J2, edge H1J1, edge H1J2 and ∠J1H2J2, edge H2J1, edge H2J2 based on the backsight point.

[0060] The three-level planar measurement verification method for extra-long railway tunnels in this invention is accurate in calculation, stable in control, and widely applicable. By employing three different measurement judgment standards and three different measurement steps corresponding to different tunnel 1 excavation conditions, it can accurately determine the position of control points inside and outside the tunnel 1 during each excavation process of the tunnel 1, thereby achieving step-by-step control of the lateral sway inside the tunnel 1, and thus achieving accurate control of the lateral breakthrough accuracy of the tunnel 1. It has good prospects for promotion and application value.

[0061] Those skilled in the art will readily understand that the above description is merely 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 scope of protection of the present invention.

Claims

1. A method for verifying the three-level planar measurement inside an extra-long railway tunnel, characterized in that, Includes the following steps: S1. Set up a tunnel entrance control network outside the tunnel entrance, start tunnel excavation, and after excavating a preset distance, set up known control points inside the tunnel, and measure the known control points inside the tunnel through the tunnel entrance control network; S2. Excavate the tunnel according to the tunnel design path. After excavating a preset distance, determine whether the tunnel excavation extension area meets the conditions for adding new control points to be densified inside the tunnel. The conditions for adding new control points to be densified inside the tunnel are determined based on the tunnel excavation distance, the air composition inside the tunnel, the air humidity inside the tunnel, and the visibility between the control points to be densified inside the tunnel and their adjacent known control points inside the tunnel. S3. Determine the subsequent process based on the judgment result of S2; if the judgment result is negative, repeat S2; if the judgment result is positive, execute S4. S4. New control points to be densified within the tunnel are added in the area surrounding the tunnel face, and primary measurement is carried out on the control points to be densified within the tunnel; after the primary measurement is completed, the control points to be densified within the tunnel are converted into known control points within the tunnel. S5. Determine whether a secondary measurement area can be constructed within the tunnel excavation extension area; if not, continue excavation and proceed to step S2; if yes, construct a secondary measurement area within the tunnel excavation extension area. The criteria for determining whether the tunnel extension area can constitute a secondary measurement area are: whether the distance of the newly excavated tunnel from the previous secondary measurement area is greater than 1 km, or whether three sets of control points are set up in the newly excavated area from the previous secondary measurement area; as long as at least one of the two conditions is met, secondary measurement can be carried out. S6. Conduct secondary measurements on several sets of known control points inside the tunnel within the secondary measurement area; S7. Determine whether the tunnel excavation extension area can be measured at level 3; if yes, continue excavation and proceed to step S2; if no, perform level 3 measurement on the entire tunnel excavation area. The criteria for determining whether the tunnel extension area can constitute a Level 3 measurement area are: whether the time since the last Level 3 measurement is greater than one year or whether the distance of the new tunnel excavation is greater than 3km; Level 3 measurement can be carried out as long as at least one of the two conditions is met.

2. The method for verifying the three-level planar measurement inside a long railway tunnel according to claim 1, wherein, The primary measurement includes the following steps: Collect the spatial locations of two sets of known control points within the cave that are closest to the location of the control point to be encrypted within the cave. Measure the actual position parameters of the control points to be encrypted within the tunnel relative to the known control points within the tunnel; The first-level measurement of the calculated actual position parameters and standard position parameters is poor; Determine whether the first-level measurement error meets the first-level remeasurement limit; if so, convert the control point to be densified in the tunnel into a known control point in the tunnel and record the first-level measurement coordinates of the known control point in the tunnel; if not, remeasure the control point to be densified and other known control points around it radially, locally or entirely, and update the coordinates of the out-of-limit point after confirming that there are no errors.

3. The method for verifying the three-level planar measurement inside a long railway tunnel according to claim 2, wherein, The first-level measurement error is determined based on the traverse measurement grade; The first-order measurement error for tunnel first-class traverse surveying includes a horizontal angle error of no more than 2.3″ and a distance error of no more than 2mD; the first-order measurement error for tunnel second-class traverse surveying includes a horizontal angle error of no more than 2.8″ and a distance error of no more than 2mD; where mD is the distance measurement error of the total station.

4. The method for verifying the three-level planar survey inside an extra-long railway tunnel according to any one of claims 1 to 3, wherein, The secondary survey of the entire tunnel excavation area includes the following steps: Collect the spatial locations of the two sets of known control points inside the tunnel that are closest to the secondary measurement area; Using the two sets of known control points inside the tunnel as starting points, the secondary measurement coordinates of several sets of known control points in the secondary measurement area are recalculated. The difference between the secondary measurement coordinates of each group of known control points calculated from the secondary measurement process and the primary measurement coordinates of each group of known control points is calculated. Determine whether the deviation of the secondary measurement meets the tolerance limit of the secondary measurement; if yes, take the average of the results of the primary measurement and the secondary measurement; if no, conduct partial or full remeasurement of the densified control point results of the primary measurement, and update the coordinates of the out-of-limit points after confirming that there are no errors.

5. The method for verifying the three-level planar measurement inside an extra-long railway tunnel according to claim 4, wherein, The grade of secondary measurement is determined based on the traverse measurement level. The tolerance limit for the second-level measurement of the first-order traverse surveying grade of tunnels, including the lateral coordinate tolerance, is 14 d mm; the tolerance limit for the second-level measurement of the second-order traverse surveying grade of tunnels, including the lateral coordinate tolerance, is 17 d mm, where d is the length from the starting point of the re-measurement to the ending point of the re-measurement, in km.

6. The method for verifying the three-level planar survey inside an extra-long railway tunnel according to any one of claims 1 to 3, wherein, The three-level survey of the entire tunnel excavation area includes the following steps: Measure the location of the control network at the tunnel entrance to ensure its accuracy. Based on the tunnel portal control network, calculate the third-level measurement coordinates of all known control points inside the tunnel relative to the tunnel portal control network; The difference between the tertiary survey coordinates of each group of known control points and the secondary survey coordinates of each group of known control points is calculated when comparing the tertiary survey coordinates. Determine whether the deviation of the third-level measurement meets the third-level measurement limit; if so, take the average of the results of the second-level measurement and the third-level measurement; if not, conduct partial or complete remeasurement of the densified control point results of the second-level measurement, and update the coordinates of the out-of-limit points after confirming that there are no errors.

7. The method for verifying the three-level planar measurement inside a long railway tunnel according to claim 6, wherein, The error in Level III measurement is determined based on the traverse measurement level; The tolerance limit for the third level of traverse surveying in first-order tunnels, including the lateral coordinate tolerance, is 14 dmm; the tolerance limit for the third level of traverse surveying in second-order tunnels, including the lateral coordinate tolerance, is 17 dmm.

8. The method for verifying the three-level planar measurement inside a long railway tunnel according to claim 6, wherein, Measuring the location of the control network at the tunnel entrance to ensure its accuracy includes the following steps: Calculate the theoretical horizontal angle and theoretical side length of the backsight control point and the entrance control point outside the tunnel; Measure the horizontal angle and side length of the backsight control point and the entrance control point outside the tunnel; Calculate the difference between the measured horizontal angle and the theoretical horizontal angle, and calculate the difference between the theoretical side length and the measured side length; Determine the limits for horizontal angle difference and side length difference based on the tunnel's measurement grade; Determine whether the difference in horizontal angle and the difference in side length meet the limits for horizontal angle difference and side length difference, respectively. If they both meet the limits, the positions of the tunnel backsight control point and the tunnel entry control point are determined to be stable, and their coordinates can be used as the starting point for the tunnel control network. If one of them does not meet the limit, the tunnel backsight control point and the tunnel entry control point should be remeasured, the unstable points should be identified and their coordinates updated, and the above steps should be repeated.

9. The method for verifying the three-level planar measurement inside a long railway tunnel according to claim 8, wherein, When the measurement grade of a tunnel is Special, the tolerance limit for horizontal angle difference is no greater than 2″ and the tolerance limit for side length difference is no greater than 2σmm; when the measurement grade of a tunnel is First, the tolerance limit for horizontal angle difference is no greater than 3″ and the tolerance limit for side length difference is no greater than 2σmm.

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