A small-radius high-buried-depth vertical shaft high-precision connection measurement method based on a shared reference point

Abstract

The application relates to a small-radius high-buried-depth shaft high-precision connection measurement method based on a shared reference point, relates to the technical field of engineering measurement, and aims to solve the problems of traditional methods, such as reference point redundancy, complex equipment, significant error accumulation, and the inability to adapt to shafts with a clearance radius of less than or equal to 8 m and a buried depth of more than 300 m. A shared system of one reference on the well and two references underground is created, wherein the underground reference point P serves as a plane coordinate reference, an azimuth reference and an elevation reference, and no additional multi-type reference needs to be laid out; a high-precision industrial laser zenith instrument is used for upward measurement from the well bottom to the well mouth, the advantages of stable well bottom environment and less cross interference are used to improve the precision, and the laser receiving target only needs to be installed at the well mouth. In the technical scheme, the plane transfer error is less than or equal to + / - 5 mm, the azimuth error is less than or equal to + / - 3'', and the elevation error is less than or equal to + / - 3 mm. Compared with the traditional method, the precision, efficiency and benefit are significantly improved, and the requirements of millimeter-level connection measurement precision are fully met.

Description

Technical Field

[0001] This invention relates to the field of engineering surveying technology, and in particular to a high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared benchmarks. Background Technology

[0002] Vertical shaft connection surveying is a core technology for achieving a unified coordinate system between the ground and underground, and its accuracy directly determines the quality of subsequent excavation and breakthrough in tunnel engineering. With the development of engineering design and construction technology, the number of small-radius, high-depth vertical shafts with burial depths exceeding 300m and clearance radii ≤8m is increasing, and traditional surveying methods have inherent limitations:

[0003] (1) The problem of baseline redundancy and error accumulation in traditional methods

[0004] In existing technologies, the suspended weight wire method requires 2-4 steel wires to be suspended in the vertical shaft (2-3 wires are required for triangulation measurement). Although the laser plumb line method does not require steel wires, it still requires "top-down" projection and the instrument to be set up at the wellhead. Both methods require the establishment of at least 6 benchmark points (2-3 on the ground + 4-5 underground), and the plane, azimuth, and elevation benchmarks are independent of each other. The error is transmitted through multiple links (such as first measuring the plane coordinates of at least 2 points by connecting triangulation and then transmitting the azimuth through intersection or gyroscope). At a burial depth of 300m, the cumulative plane error is ≥±50mm and the azimuth error is ≥±20″, which completely fails to meet the millimeter-level requirements.

[0005] (2) Wellhead environmental interference and projection direction defects

[0006] Traditional methods (using suspended steel wires and plumb bobs) all employ a "top-down" projection mode: steel wires and a weighted suspension device or plumb bob need to be erected at the wellhead. However, the dense construction equipment (hoisting machines, cranes) at the wellhead, vibration amplitude ≥0.5mm, and airflow velocity ≥3m / s make it easy for the projection point deviation to exceed the limit. In addition, a large amount of working space needs to be reserved at the wellhead (at least ≥1.5m² for one benchmark point, and it is even more difficult to arrange multiple benchmark points). In small-radius vertical shafts with a radius ≤8m, it is easy to conflict with construction, requiring the removal of other obstructing equipment. A single measurement requires suspending wellhead operations for 8~12 hours, which seriously affects the construction period.

[0007] (3) Deficiencies of existing technology

[0008] Patent searches revealed that existing technologies have failed to address the core pain point of "benchmark sharing + bottom-up projection":

[0009] CN113865559A (Automatic Contact Measurement for Ultra-Deep Shafts): Requires vertical traverse transmission using multiple total stations, and still requires equipment to be installed at the shaft opening; ≥4 benchmark points are needed.

[0010] CN106705947A (Coordinate Transfer of Triangular Pyramid): Relies on complex geometric models, the projection direction is still "from top to bottom", and the anti-interference is weak.

[0011] CN111044042A (Gyroscope + Inertial Navigation): Focuses on dynamic positioning, but still requires multiple reference points for static positioning, and is not suitable for small-radius vertical shafts.

[0012] Therefore, developing a vertical shaft connection measurement method that features "baseline sharing, bottom-up projection, and strong anti-interference" has become the key to solving the measurement problem of small-radius, high-depth vertical shafts. Summary of the Invention

[0013] To address the shortcomings of existing technologies, this invention provides a high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points, specifically including the following steps:

[0014] This invention innovatively constructs a shared system of "1 benchmark above ground + 2 benchmarks below ground". The shared benchmark point P below ground integrates three types of benchmarks: plane, azimuth, and elevation. A high-precision industrial laser zenith instrument is used for "bottom-up" projection, which works in conjunction with the NTS split-type fully automatic gyro total station to avoid wellhead interference and achieve "fewer benchmarks, single direction, high precision, and low cost" connection measurement.

[0015] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points, comprising the following steps:

[0016] S1: Establish a near-well densified control network. Taking the GNSS primary control network around the vertical shaft as the starting point, several near-well control points are set up within the preset range to form a closed or attached control network. High-precision measuring equipment is used to observe and record environmental parameters synchronously according to the preset accuracy for atmospheric correction. After adjustment by professional software, the positional error of the weakest point of the control network meets the preset requirements.

[0017] S2: Deploy a shared system

[0018] S21: Wellhead 1 reference setting, a forced centering target device is installed at the shaft sealing plate away from the interference source. The target plate is equipped with a reflective component at the center and a calibration target. There is no need to set up measuring instruments at the wellhead.

[0019] S22: Downhole reference setting 2. A shared reference point is set at the bottom of the well directly below the forced centering mark. The shared reference point serves as a plane coordinate reference, azimuth reference, and elevation reference. An auxiliary reference point is set at a preset distance in front of the shared reference point. The line connecting the two reference points forms the starting side of the downhole traverse. The measured side length error meets the preset accuracy.

[0020] S3: Planar reference transfer. A vertical projection device is installed at the shared reference point to project a positioning beam from the bottom of the well to the wellhead, automatically aiming at the reflective component of the surface reference. A high-precision measuring instrument is set up at the near-well control point, and an observation prism is set up at the surface reference. The coordinates of the projection points on the target are observed in multiple rounds. The coordinates of the target projection points are calculated by the polar coordinate method to complete the plane reference transfer from the ground to the shared reference point.

[0021] S4: Based on the azimuth transfer of the shared reference point, a gyro total station is used. The shared reference point is used as the observation reference point. The closed observation procedure of "known surface edge - downhole starting edge - known surface edge" is executed to calculate the coordinate azimuth and accuracy of the downhole starting edge.

[0022] S5: Elevation transfer based on shared benchmark points: A high-precision measuring instrument is set up on the shared benchmark point, and the reflector observation mode is switched. The reflector of the benchmark above the well is vertically aimed from the bottom of the well. The vertical distance is measured multiple times. After deducting the height of the instrument and the thickness of the reflector, the elevation of the shared benchmark point is back-calculated by combining the elevation of the benchmark above the well.

[0023] S6: Downhole traverse survey: Using the line connecting two reference points in the well as the starting side, observe the horizontal angle and side length according to the preset traverse accuracy. The downhole control points are arranged in a closed traverse group by crossing traverses. Combine the coordinates of the shared reference point and the azimuth of the starting side, and calculate the coordinates of each traverse point in the well through rigorous adjustment.

[0024] Preferably, the small-radius, high-depth vertical shaft meets the following requirements: net cross-sectional radius ≤ 8m, burial depth > 300m; the method does not require the installation of measuring instruments at the wellhead, but only requires the installation of a laser receiving target as a reference above the well, thus avoiding the impact of interference and vibration from wellhead construction equipment on the observation accuracy.

[0025] Preferably, the GNSS primary control network in S1 is a second-order control network, the preset range is within a 1km radius of the shaft, the number of near-shaft control points is 3-4, forming a triangular or geodetic quadrilateral control network; the high-precision measuring equipment is a high-precision total station with an angle measurement accuracy ≤0.5″ and a distance measurement accuracy ≤1mm+1ppm, the environmental parameters include temperature and air pressure, and the positional error of the weakest point of the control network after adjustment is ≤±4mm.

[0026] Preferably, the "1 benchmark above ground + 2 benchmarks below ground" shared system described in S2 is specifically as follows:

[0027] The forced centering disc device of Inoue 1 reference has a diameter ≥220mm, the reflective component is a high-precision reflective sheet, and the calibration target is a dynamic calibration target;

[0028] The shared reference point underground is a cylindrical forced centering marker made of C30 concrete, with a diameter ≥300mm and a height ≥1.5m; the auxiliary reference point is a second forced centering marker, located 200~300m in front of the shared reference point.

[0029] The vertical deviation between the shared reference point and the center of the forced centering device at the wellhead is ≤±2mm, and it is calibrated in real time by the vertical projection equipment in S3.

[0030] Preferably, the vertical projection device mentioned in S3 is a high-precision industrial laser zenith meter, with a standard deviation of ≤1 / 400,000 for one measurement and a vertical projection point deviation of ≤±1.5mm; the multi-measurement observation consists of “2 measurements each for forward and reverse mirrors”, with a difference between horizontal angle measurements of ≤1.5″, and the distance observation is taken as the average of ≥4 measurements.

[0031] The observation prism is a Leica-specific small prism;

[0032] The laser zenith telescope projects from the bottom of the well to the wellhead. Taking advantage of the stable environment at the bottom of the well, the projection error is reduced by 60% compared to the traditional top-down projection method.

[0033] Preferably, the plane reference transfer error in S3 is calculated according to the formula...

[0034] = Calculation, where For the measurement error of the vertical projection equipment, This is for the measurement error of the total station. This refers to the near-wellbore control network error.

[0035] Preferably, the gyro total station mentioned in S4 is an NTS split-type fully automatic gyro total station, and the closed observation program is as follows:

[0036] A gyro total station was set up at the near-well control point, aimed at the adjacent known endpoints, and three rounds of observations were conducted using the integration method to calculate the instrument constant. A gyro total station was then set up at the shared reference point downhole, aimed at the auxiliary reference point, and three more rounds of observations were conducted, with the difference between rounds ≤ 10″. The observations were then reviewed on the surface, and the most probable value of the instrument constant was determined. The standard orientation error ∆a = 5″ was calculated, and the average of the three measurements was taken to determine the orientation mean error. 2.89, azimuth reference transmission error ≤ ±3″.

[0037] Preferably, the multi-repetition observation in S5 is "3 repetitions each for forward and reverse mirrors", with the difference between repetitions ≤3mm;

[0038] Elevation transfer error is calculated using the formula Calculation, where To measure the mean square error of elevation difference in ground-based elevation surveying, This represents the mean square error of vertical elevation measurement using a total station.

[0039] Preferably, the preset traverse accuracy in S6 is third-order traverse accuracy: horizontal angle observation is performed by two rounds of forward and reverse measurements, and side length observation is performed by forward and reverse measurements; the closed traverse group formed by the cross traverse arrangement, after rigorous adjustment, has a position error of the weakest point of the downhole traverse ≤ ±10mm.

[0040] Preferably, the high-precision measuring instrument used in S3 and S5 is the same high-precision total station. When the instrument switches observation modes, there is no need to re-set it up. The observation parameters are automatically calibrated through a preset program, which reduces the impact of instrument setup errors on measurement accuracy and shortens the overall measurement operation time.

[0041] This invention provides a high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points, which has the following beneficial effects.

[0042] 1. The implementation of this invention solves the problem of redundant benchmarks: traditional methods require ≥6 benchmarks, with independent plane / azimuth / elevation benchmarks, resulting in multiple error transmission links; it avoids the defects of projection direction: "top-down" projection is affected by wellhead vibration and airflow interference, resulting in low accuracy; it eliminates the problem of poor spatial adaptability, as suspending multiple steel wires requires a large working space and is not suitable for vertical shafts with a radius ≤8m; it solves the contradiction of difficult cost control and low efficiency: traditional methods require a large number of workers, take a long time, and have high equipment costs, which conflicts with the construction schedule.

[0043] 2. Compared with traditional vertical shaft connection measurement methods (such as the suspended weight steel wire method and the laser plumb line method), the implementation of this invention achieves a comprehensive breakthrough in terms of benchmark simplification, measurement stability, accuracy reliability, work efficiency, and cost control. The beneficial effects are as follows:

[0044] (1) It pioneered a shared system of 1 benchmark above ground and 2 benchmarks below ground, which can transmit plane, azimuth and elevation with only 3 benchmark points. The P point below ground also serves as the benchmark transmission point for all three types, reducing the number of benchmarks by 80% and the error transmission links by 50%, thereby reducing the risk of error superposition from the source.

[0045] (2) High-precision laser projection from bottom to top is adopted to avoid wellhead vibration and airflow interference. The plane error is ≤ ±5mm, the elevation is ≤ ±3mm, and the azimuth angle is ≤ ±3″, reaching millimeter-level accuracy, which meets the accuracy requirements of the connection measurement of deep vertical shafts and lays the foundation for subsequent high-precision tunnel breakthrough measurement.

[0046] (3) A single measurement takes ≤4 hours and only 3 people are needed to operate. The equipment and labor costs are reduced by more than 35%. It is also suitable for vertical shafts with a radius of ≤8m and a depth of >300m, which completely solves the pain points of traditional methods such as redundancy, low efficiency and poor scene adaptability. Attached Figure Description

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0048] Figure 1 This is a schematic diagram illustrating an embodiment of the present invention. Detailed Implementation

[0049] like Figure 1 As shown, this invention provides a high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared benchmarks. Through a four-step collaborative technical approach—"establishing near-well control benchmarks, projecting plane benchmarks, orienting azimuth benchmarks, and transferring elevation benchmarks"—it achieves millimeter-level accuracy transfer. The specific steps are as follows:

[0050] (1) Step S1: Establishment of near-well densification control network

[0051] Based on the primary second-order GNSS control network around the shaft, 3-4 near-shaft control points are established within a 1km radius, forming a triangle or geodetic quadrilateral. Observations are conducted using a high-precision total station, with an angular accuracy ≤0.5″ and a distance accuracy ≤1mm+1ppm. Temperature and air pressure are recorded simultaneously during distance observations, and atmospheric corrections are applied. Adjustment calculations are performed using specialized software to ensure that the positional error of the weakest point in the control network is ≤±4mm, providing a stable benchmark for subsequent transfer.

[0052] (2) Step S2: Deployment of the "1 benchmark above ground + 2 benchmarks below ground" shared system

[0053] 1) Inoue 1 reference: Laser receiving target (minimalist design)

[0054] Installation location: The wellhead sealing plate should be located away from the vibration area of ​​the hoisting machine. No instruments need to be installed; only a 220mm diameter forced centering plate needs to be fixed, upon which a laser receiving target is mounted. When elevation reference transmission is required, a reflective sheet with a thickness of ±0.1mm can be pasted to the center of the side facing the bottom of the well.

[0055] Advantages: Compared with the traditional wellhead installation of suspended weights and wire rope devices / plumb bobs, this target only requires 0.1m² of installation space, reducing the workload by 90% and avoiding the impact of wellhead vibration on the instrument.

[0056] 2) Downhole reference 2: Shared reference point P + auxiliary reference point Q

[0057] Shared benchmark point P (core): A C30 concrete cylindrical marker pier (1.5m high, 300mm in diameter) is poured at the bottom of the well directly below the target. Auxiliary benchmark point Q: A marker pier of the same specification is buried more than 200m in front of point P. The measured side length of PQ has an error of ±1.8mm, forming the starting benchmark side of the underground traverse.

[0058] (3) Step S3: Transfer of plane reference from bottom to top

[0059] The innovative approach combines a high-precision industrial laser zenith instrument with a dynamic calibration target to overcome the limitations of small-radius space. The projection direction is from point P at the bottom of the well to the target at the wellhead, which is the opposite of the traditional "top to bottom" method. There are no large equipment at the bottom of the well, the airflow velocity is ≤1m / s, the vibration is ≤0.1mm, and the projection point stability is 3 times higher than that at the wellhead.

[0060] After the benchmark pier has settled and stabilized, install an EZS-40 high-precision industrial laser zenith meter on it (standard deviation of one measurement cycle ≤ 1 / 400,000, vertical projection deviation ≤ ±1.5mm).

[0061] A Leica TS60 total station (angle measurement 0.5″, distance measurement 1mm+1ppm) was set up at the near-well control point on the ground. A Leica-specific small prism was set up on the target. The coordinates of the points projected on the target were observed using the "two rounds of forward and reverse measurement" mode. The difference between horizontal angle measurements was ≤1.5″, and the distance was measured ≥4 times and the average value was taken. The plane reference was transferred by polar coordinate method.

[0062] Planar transmission error is calculated using the formula = Calculation, where The error of the laser zenith telescope projecting from bottom to top is ≤±1.5mm. The measurement error of the total station is ≤ ±2mm. The near-well control network error is ≤ ±4 mm, and the final coordinate reference point plane error is ≤ ±5 mm.

[0063] (4) Step S4: Azimuth angle transfer based on shared reference point P

[0064] High-precision azimuth angle transfer is achieved using an NTS split-type fully automatic gyro total station, executing a closed observation procedure of "known ground edge - underground directional edge - known ground edge":

[0065] ① Surface observation: An NTS fully automatic gyro total station is set up at the near-well control point, aimed at the adjacent known edge endpoints, and three rounds of observation are conducted using the "integral method". The instrument constant K is calculated as: known edge azimuth - mean gyro azimuth.

[0066] ② Downhole observation: Move to point P, aim at point Q, and repeat the observation 3 times. The difference between the two observations should be ≤10″.

[0067] ③ Ground observation, same as ①, then find the most probable value of the instrument constant and evaluate the error of a single measurement.

[0068] ④ Calculate the true north azimuth angle αPQ of the starting side in the well = mean azimuth angle of the underground gyroscope + K, and the standard orientation error of the fully automatic gyroscope total station in one pass. Take the average of three values, and the orientation standard error is: 2.89″, azimuth reference transmission error ≤ ±3″.

[0069] (5) Step S5: Elevation transfer based on shared reference point P

[0070] Innovative use of high-precision reflector mode vertical distance measurement technology with total station:

[0071] A total station was set up on point P, the marker at the bottom of the well, and switched to high-precision reflector mode (distance measurement accuracy 1mm + 1.5ppm). The reflector was vertically aimed at the reflector on the forced centering marker at the wellhead.

[0072] The vertical distance is observed by "three measurements each with the forward and reverse mirrors". The difference between measurements is ≤2mm. The instrument height and reflector thickness are deducted when calculating the distance. The elevation of point P is calculated by back-calculating the elevation of the forced centering scale. The elevation transfer error is ≤±3mm, which overcomes the defects of traditional steel tape height transfer that are affected by temperature and tension.

[0073] The elevation transfer accuracy is calculated as follows:

[0074] =± =±1.8mm

[0075] in The mean square error of elevation difference measurement for ground-based elevation transfer is calculated based on a second-order leveling transfer of 1km.

[0076] =± =±1.0mm

[0077] This represents the standard error of vertical elevation measurement using a total station (total station distance measurement error).

[0078] =1+1.5 0.309 = 1.46 mm

[0079] Taking into account other high-level and unforeseen measurement errors, the final elevation error can be determined to be ≤ ±3mm.

[0080] (6) Step 6: Downhole traverse survey

[0081] Using PQ as the starting side, a high-precision total station is used to observe the horizontal angle (two measurements each with forward and reverse sights) and the side length (forward and backward measurements) with the accuracy of a third-order traverse. The downhole control points are arranged in a cross-traverse pattern to form a closed traverse group. The coordinates of each downhole traverse point are calculated using a rigorous adjustment mode based on the coordinates of point P and αPQ to ensure that the weakest mean square error of the traverse is ≤ ±10mm.

[0082] Taking a vertical shaft in a certain section of the Yangtze River Diversion Project as an example, the shaft has a net radius of 7.8m and a burial depth of 310m. Based on the estimation of the breakthrough error, the required accuracy for shaft connection measurements is derived: horizontal accuracy ≤ ±10mm, vertical accuracy ≤ ±3mm, and coordinate azimuth ≤ ±5″. The specific implementation process is as follows:

[0083] 1. Implementation Preparation

[0084] The instruments and equipment include: EZS-40 laser zenith instrument (dynamic calibration target), Leica TS60 total station, NTS split-type fully automatic gyro total station (north-finding accuracy ≤5″), and forced centering compass.

[0085] Site conditions: During the survey, the hoist at the wellhead must be shut down, and the airflow velocity at the bottom of the well must be ≤1m / s.

[0086] 2. Implementation Steps

[0087] (1) Set up near-well densification control points J1-J4, and conduct second-order observation of the corner network using a total station. The positional error of point J3 is ±4.2mm and that of point J4 is ±3.8mm.

[0088] (2) Install the wellhead forced centering target and laser dynamic calibration target, and bury the cylindrical forced centering target at the bottom of the well. After the settlement is stable, use a high-precision laser zenith instrument to vertically project the point; the laser projection deviation is ±1.2mm; the total station observes and calculates the target coordinates, and the cumulative projection error is ±5.1mm.

[0089] (3) Point Q was buried underground (270.489m from point P); the instrument constant K was obtained by secondary ground observation using an NTS split-type fully automatic gyro total station; the azimuth angle of the starting side of the traverse was obtained by underground observation αPQ = 89°12′34.64″, with an error of ±2.7mm;

[0090] (4) The average vertical distance observed by the total station without prism was 309.1667m, and the elevation error of point P was ±2.1mm;

[0091] (5) Set up the downhole traverse points, using cross traverses to form a closed traverse with the starting edge for adjustment calculation. The mean square error of the weakest point of the traverse is ±5.8mm.

[0092] 3. Effect Verification

[0093] Comparison of two independent measurement results: the coordinate difference of point P is ΔX=+3.2mm, ΔY=-2.8mm, the elevation difference is ΔH=+1.5mm, and the difference in azimuth angle of the starting side is ±4.5″, which meets the engineering requirements.

Claims

1. A high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points, characterized in that, Includes the following steps: S1: Establish a near-well densified control network. Taking the GNSS primary control network around the vertical shaft as the starting point, several near-well control points are set up within the preset range to form a closed or attached control network. High-precision measuring equipment is used to observe and record environmental parameters synchronously according to the preset accuracy for atmospheric correction. After adjustment by professional software, the positional error of the weakest point of the control network meets the preset requirements. S2: Deploy a shared system S21: Wellhead 1 reference setting, a forced centering target device is installed at the shaft sealing plate away from the interference source. The target plate is equipped with a reflective component at the center and a calibration target. There is no need to set up measuring instruments at the wellhead. S22: Downhole reference setting 2. A shared reference point is set at the bottom of the well directly below the forced centering mark. The shared reference point serves as a plane coordinate reference, azimuth reference, and elevation reference. An auxiliary reference point is set at a preset distance in front of the shared reference point. The line connecting the two reference points forms the starting side of the downhole traverse. The measured side length error meets the preset accuracy. S3: Planar reference transfer. A vertical projection device is installed at the shared reference point to project a positioning beam from the bottom of the well to the wellhead, automatically aiming at the reflective component of the surface reference. A high-precision measuring instrument is set up at the near-well control point, and an observation prism is set up at the surface reference. The coordinates of the projection points on the target are observed in multiple rounds. The coordinates of the target projection points are calculated by the polar coordinate method to complete the plane reference transfer from the ground to the shared reference point. S4: Based on the azimuth transfer of the shared reference point, a gyro total station is used. The shared reference point is used as the observation reference point. The closed observation procedure of "known ground edge - downhole starting edge - known ground edge" is executed to calculate the coordinate azimuth and accuracy of the downhole starting edge. S5: Elevation transfer based on shared benchmark points: A high-precision measuring instrument is set up on the shared benchmark point, and the reflector observation mode is switched. The reflector of the benchmark above the well is vertically aimed from the bottom of the well. The vertical distance is measured multiple times. After deducting the height of the instrument and the thickness of the reflector, the elevation of the shared benchmark point is back-calculated by combining the elevation of the benchmark above the well. S6: Downhole traverse survey: Using the line connecting two reference points in the well as the starting side, observe the horizontal angle and side length according to the preset traverse accuracy. The downhole control points are arranged in a closed traverse group by crossing traverses. Combine the coordinates of the shared reference point and the azimuth of the starting side, and calculate the coordinates of each traverse point in the well through rigorous adjustment.

2. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The small-radius, high-depth vertical shaft meets the following requirements: net cross-sectional radius ≤ 8m, burial depth > 300m; the method does not require the installation of measuring instruments at the wellhead, but only requires the installation of a laser receiving target as a reference above the well, thus avoiding the impact of interference and vibration from wellhead construction equipment on the observation accuracy.

3. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The GNSS primary control network mentioned in S1 is a second-order control network. The preset range is within a 1km radius of the shaft. The number of near-shaft control points is 3 to 4, forming a triangular or geodetic quadrilateral control network. The high-precision measuring equipment is a high-precision total station with an angle measurement accuracy of ≤0.5″ and a distance measurement accuracy of ≤1mm+1ppm. The environmental parameters include temperature and air pressure. After adjustment, the positional error of the weakest point in the control network is ≤±4mm.

4. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The "1 benchmark above ground + 2 benchmarks below ground" shared system described in S2 is specifically as follows: The forced centering disc device of Inoue 1 reference has a diameter ≥220mm, the reflective component is a high-precision reflective sheet, and the calibration target is a dynamic calibration target; The shared reference point underground is a cylindrical forced centering marker made of C30 concrete, with a diameter ≥300mm and a height ≥1.5m; the auxiliary reference point is a second forced centering marker, located 200~300m in front of the shared reference point. The vertical deviation between the shared reference point and the center of the forced centering device at the wellhead is ≤±2mm, and it is calibrated in real time by the vertical projection equipment in S3.

5. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The vertical projection equipment mentioned in S3 is a high-precision industrial laser zenith instrument, with a standard deviation of ≤1 / 400,000 for one measurement and a vertical projection point deviation of ≤±1.5mm; the multi-measurement observations are "2 measurements each for forward and reverse mirrors", the difference between horizontal angle measurements is ≤1.5″, and the distance observations are ≥4 times and the average value is taken. The observation prism is a Leica-specific small prism; The laser zenith telescope projects from the bottom of the well to the wellhead. Taking advantage of the stable environment at the bottom of the well, the projection error is reduced by 60% compared to the traditional top-down projection method.

6. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The plane datum transfer error in S3 is calculated according to the formula. = Calculation, where For the measurement error of the vertical projection equipment, This is for the measurement error of the total station. This refers to the near-wellbore control network error.

7. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The gyro total station described in S4 is an NTS split-type fully automatic gyro total station. The closed observation program is as follows: A gyro total station was set up at the near-well control point, aimed at the adjacent known endpoints, and three rounds of observations were conducted using the integration method to calculate the instrument constant. A gyro total station was then set up at the shared reference point downhole, aimed at the auxiliary reference point, and three more rounds of observations were conducted, with the difference between rounds ≤ 10″. The observations were then reviewed on the surface, and the most probable value of the instrument constant was determined. The standard orientation error ∆a = 5″ was calculated, and the average of the three measurements was taken to determine the orientation mean error. 2.89, azimuth reference transmission error ≤ ±3″.

8. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The multi-repetition observation described in S5 is "3 repetitions each for forward and reverse mirrors", with an inter-repetition difference ≤3mm; Elevation transfer error is calculated using the formula Calculation, where To measure the mean square error of elevation difference in ground-based elevation surveying, This represents the mean square error of vertical elevation measurement using a total station.

9. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The preset traverse accuracy mentioned in S6 is third-order traverse accuracy: horizontal angle observation is performed by two rounds of forward and reverse measurements, and side length observation is performed by forward and reverse measurements; the closed traverse group formed by the cross traverse arrangement, after rigorous adjustment, has a positional error of the weakest point of the downhole traverse ≤ ±10mm.

10. The high-precision connection measurement method for small-radius, high-depth vertical shafts based on shared reference points according to claim 1, characterized in that: The high-precision measuring instrument used in S3 and S5 is the same high-precision total station. When the instrument switches observation modes, there is no need to re-set it up. The observation parameters are automatically calibrated through a preset program, which reduces the impact of instrument setup errors on measurement accuracy and shortens the overall measurement operation time.

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