Special polygon connection measurement method for small well mouth long interval

Abstract

The present application relates to the technical field of tunnel shaft connection measurement of urban rail transit engineering, in particular to a small well mouth long section special polygon connection measurement method, comprising the following steps: S1, suspending not less than four steel wires in the shaft, the angle formed by each two steel wires and the ground near-well point and the underground control point both meet the requirement of less than 1°, and the four steel wires and the ground near-well point and the underground control point form a special polygon; S2, setting up a total station at the ground near-well point and the underground control point at the same time, completing orientation by viewing the control point, and obtaining the angle and distance observation of the four steel wires and the control point. The beneficial effects of the present application solve the problem that the small well mouth orientation method is not suitable for non-main line well mouth and poor main line well mouth site limitations, greatly improve the applicability of the method, improve the short board of the existing resection method connection measurement orientation precision, and meet the small well mouth long section connection measurement precision requirement under the existing complex urban conditions.

Description

Technical Field

[0001] This invention relates to the field of tunnel shaft connection measurement technology in urban rail transit engineering, specifically a method for measuring special polygonal connections in long sections with small shaft openings. Background Technology

[0002] Subway stations are generally constructed using the open-cut method. The corresponding connection measurement method for tunnel excavation is primarily two-shaft orientation, typically using pre-reserved shafts in the subway station to transfer coordinates and elevations between the surface and underground shafts. In recent years, constrained by the existing urban environment, particularly the demolition and land acquisition in bustling urban areas, cut-and-cover stations have become the mainstream, and tunnel-first, station-later construction has become the norm. Small vertical shafts are reserved in stations for the separate hoisting of the tunnel boring machine and the transfer of coordinates for initial connection measurements. Furthermore, some shafts are located off-line, often connected to the main line via cross passages, which places higher demands on conventional connection measurement methods. Single-shaft orientation (connection triangle, double-connection triangle) connection measurement methods have high requirements for shaft size and the surrounding environment. Conventional re-intersection methods lack sufficient accuracy in underground control side orientation, making it difficult to meet the accuracy requirements for long-distance connection measurements with small shafts under complex site conditions.

[0003] Currently, the coordinate transfer of vertical shaft connection measurement is commonly carried out in the form of gyroscope orientation method, connection triangle method (one-well orientation method), borehole point projection method (two-well orientation method), direct traverse orientation method, and conventional resection method. However, each method has specific conditions for use and advantages and disadvantages. (1) Although the gyroscope orientation method has the characteristics of small workload, low labor intensity and fast positioning, it has disadvantages such as low single positioning accuracy (single orientation 20″), expensive gyroscope equipment, high purchase cost, and high technical level requirements for instrument operators. (2) Although the connection triangle method (one-well orientation method) has high positioning accuracy and moderate workload, it has high requirements for the on-site vertical shaft environment. The on-site conditions must meet the following: ① The distance a between the two steel wires should not be less than 5m and should be as long as possible. ② The included angle α of the steel wires should be less than 1° and form a straight triangle. ③ b / a and b' / a should be less than 1.5. When making connection measurements, the near well point should be as close as possible to the nearest steel wire and the angles α and α' should be measured accurately. Due to site limitations, construction shafts often cannot meet the technical requirements of the connecting triangle method (one-shaft orientation method). (3) Although the borehole projection method (two-shaft orientation method) has high positioning accuracy and convenient observation, it requires separate drilling and projection, which involves many procedures and a huge amount of preliminary preparation work. In mountainous areas or complex environments, drilling is simply not feasible. (4) Although the direct traverse orientation method is simple, for deep shafts, problems such as inconsistent traverse side lengths and excessive pitch angles often occur. This method is rarely used in mining tunnels. (5) Although the conventional resection method has low site requirements, it has disadvantages such as insufficient underground orientation accuracy, which makes it difficult to meet the orientation requirements of long-interval tunnel excavation with small shaft openings. Therefore, it is urgent to develop a special polygon connection measurement method for long-interval tunnels with small shaft openings. Summary of the Invention

[0004] The purpose of this invention is to provide a method for measuring special polygonal connections in long intervals at small wellheads, in order to solve the problems mentioned in the background art.

[0005] The technical solution of this invention is: a method for measuring special polygonal connections in long intervals at small wellheads, comprising the following steps:

[0006] S1. No fewer than four steel wires are suspended in the vertical shaft 2. Let A, B, and C be the ground starting points. The angles formed by each pair of steel wires with the ground near-well point and the underground control point are all less than 1°. The four steel wires form a special polygon with the ground near-well point and the underground control point.

[0007] S2. By simultaneously setting up a total station at the near-well point on the ground and the control point underground, the orientation is completed by backsight of the control point. The four stationary steel wires are observed multiple times simultaneously on the ground and underground parts of the shaft to obtain the angle and distance observations of the four steel wires relative to the control point.

[0008] S3. Simultaneously move and adjust the positions of the four steel wires, and re-observe to obtain the angle and distance observations between the second and third sets of steel wires and the control points.

[0009] S4. Organize the data, input the coordinates of the known control points, and use the adjustment software to perform the adjustment calculation of the special polygonal connection measurement control network of the small wellhead long interval based on the principle of steel wire coordinate transfer and multi-point intersection. The adjustment calculation yields the first set of downhole control point coordinates.

[0010] S5. Repeat the above steps to obtain the coordinates of the second and third sets of downhole control points. Compare the three sets of coordinates and take the average of the three sets of coordinates as the final result if the difference meets the requirements.

[0011] Furthermore, all steel wires are fixed at the upper end and suspended by a 10KG lead weight 5 at the lower end, remaining stationary in the damping fluid. The diameter of the steel wire is selected from 0.3mm to 0.5mm, and is determined comprehensively based on the depth and the distance between the near well point and the steel wire. The number of steel wires is not less than four, and the number of observations is not less than three.

[0012] Furthermore, both the surface near-well point and the downhole control point are forced alignment devices, which can effectively reduce alignment errors.

[0013] Furthermore, the steel wires are distributed in pairs on both sides of the vertical shaft 2, forming a special polygon. The angles formed by each pair of steel wires with the ground near-well point and the downhole control point respectively meet the requirement of being less than 1°.

[0014] Furthermore, all distance measurements should be corrected for instrument multiplication constants, air pressure, and temperature and humidity, and the steel wire measurements on the ground and underground must be synchronized.

[0015] Furthermore, A, B, and C are ground starting points, GS1, GS2, GS3, and GS4 are steel wires, and D1, D2, and D3 are downhole control points.

[0016] This invention provides an improved method for measuring special polygonal connections in long intervals at small wellheads, which has the following improvements and advantages compared to existing technologies:

[0017] (1) The method of the present invention, which describes a special polygonal connection measurement method for long intervals at small wellheads, innovatively adopts a special polygonal mesh for long interval connection measurement at small wellheads. This improves upon the extremely high requirements of the existing one-well orientation (connection triangle, double connection triangle) method for small wellheads, reducing the constraints on the side length ratio of the steel wire suspension in the field. It solves the limitation that the one-well orientation (connection triangle, double connection triangle) method for small wellheads is not applicable to non-mainline wellheads and mainline wellheads with poor conditions, greatly improving the applicability of the method.

[0018] (2) The method of the present invention is an innovative method for measuring the connection of a small wellhead in a long interval using special polygons. The special polygons are used to ensure orientation accuracy, and the coordinate accuracy is ensured by adding verification conditions. This method improves the shortcomings of the existing resection method for connection measurement, which has insufficient orientation accuracy, and can meet the accuracy requirements of the connection measurement of a small wellhead in a long interval under the complex conditions of the present city.

[0019] (3) The method of the present invention is a special polygonal connection measurement method for long intervals of small wellheads. It combines the advantages of double connection triangle connection measurement method and multi-point resection connection measurement method, and redesigns the network shape. The measurement principle is simple, the operation is highly feasible, and the technical requirements for technicians are low.

[0020] (4) The method for measuring special polygonal connections in long sections of small wellheads described in this invention has a relatively fixed mesh pattern for the connecting measurement wires, allowing for pre-design and fixation of the wire positions, which greatly reduces the workload on site. The process uses conventional instruments, without increasing additional instrument costs, resulting in low investment, low wear and tear, and simple operation both in the office and in the field with low labor intensity. It not only ensures measurement accuracy but also significantly reduces the impact of external conditions on vertical well connection measurements, demonstrating strong environmental adaptability. Attached Figure Description

[0021] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 This is a schematic diagram of the single-well directional double-connection triangle connection measurement principle of the present invention;

[0023] Figure 2 This is a schematic diagram of the multi-point resection connection measurement principle of the present invention;

[0024] Figure 3 This is a schematic diagram of the method principle of the present invention;

[0025] Figure 4 This is a schematic diagram of the method of the present invention.

[0026] Figure 5 This is a schematic diagram of the planar detection method of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Surface part; 2. Shaft; 3. Underground part; 4. Reflector; 5. Plumb bob; 6. Oil drum. Detailed Implementation

[0029] The following will be combined with the appendix Figures 1 to 4This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] This invention provides an improved method for measuring special polygonal connections over long intervals at small wellheads, such as... Figures 1-4 As shown, it includes the following steps:

[0031] 1. First, check the stability of the corners of the ground starting points A, B, and C. Once the starting points are stable and reliable, the next measurement step can proceed. The ground starting point (near the well point) B uses a forced centering device, which effectively reduces centering errors.

[0032] 2. No fewer than four steel wires GS1, GS2, GS3, and GS4 shall be suspended inside shaft 2. The angles formed by each pair of steel wires with the near-well point B on the ground and the downhole control point D1 shall all meet the requirement of being less than 1°. The four steel wires GS1, GS2, GS3, and GS4, together with the near-well point B on the ground and the downhole control point D1, shall form a special polygon.

[0033] 3. The four steel wires GS1, GS2, GS3, and GS4 are fixed at the top and have a 10KG lead weight 5 suspended at the bottom, resting in the oil drum 6. The oil drum 6 refers to the damping fluid drum; in practice, the damping fluid is commonly referred to as "oil," and the damping fluid drum is commonly called "oil drum 6." The lead weight 5 must not rest against the bottom or the drum wall. Reflective patches should be stably attached to the top and bottom of the steel wires; the specific position depends on the site conditions. The steel wire diameter should be selected from 0.3mm to 0.5mm, determined based on the depth and the distance between the nearest well point and the steel wire.

[0034] 4. Set up a total station near the well point B within the site area of ​​shaft 2, and complete orientation by backsight A. Set up a total station at control point D1 underground, and complete orientation by backsight D2. After the steel wires are stabilized, use the full-circle observation method to observe the four steel wires GS1, GS2, GS3, and GS4 simultaneously on the ground and underground to obtain the angle L and distance S between the steel wires and the control point. All distance observations should be corrected for instrument multiplication constant, air pressure, and temperature and humidity.

[0035] 5. Simultaneously move the positions of the four steel wires (GS1, GS2, GS3, GS4), re-set the instrument on the ground and underground, and repeat the above steps to obtain the observations of the angle L and distance S between the second and third sets of steel wires and the control points.

[0036] 6. Organize the data, input the coordinates of the ground starting point (A, B, C), and use adjustment software to perform adjustment calculations of the special polygon connection measurement control network for long intervals in small wellheads based on the principle of steel wire coordinate transfer and multi-point intersection. The adjustment calculations yield the coordinates of the first set of downhole control points (D1, D2, D3).

[0037] 7. Repeat the above steps to obtain the coordinates of the second and third sets of downhole control points (D1, D2, D3);

[0038] 8. Compare the coordinates and azimuths of the three sets of control points respectively. If the difference in the results meets the requirements of the specifications, take the average of the three sets as the final result. Otherwise, the measurement needs to be repeated.

[0039] 9. After the measurement is completed, remove the plumb bob and steel wire, tidy up the instruments, and plan the next measurement work.

[0040] Furthermore, both the surface near-well point and the downhole control point are equipped with forced centering devices, which can effectively reduce centering errors. The steel wires are distributed in pairs on both sides of shaft 2, forming a special polygon. The angles formed by each pair of steel wires with the surface near-well point and the downhole control point respectively meet the requirement of being less than 1°. All distance observations should be corrected for instrument multiplication constants, air pressure, and temperature and humidity. The steel wires must be measured synchronously on the surface and underground.

[0041] Furthermore, A, B, and C are the ground starting points, GS1, GS2, GS3, and GS4 are steel wires, and D1, D2, and D3 are downhole control points.

[0042] like Figure 3 As shown, this means that the included angle between any two steel wires above ground (or below ground) is less than 1°. On-site, the positions of the four steel wires were adjusted so that all four wires were within a 1° sector range between the surface near-wellpoint and the underground control point. Specifically, above ground, ∠GS1-B-GS2, ∠GS1-B-GS4, ∠GS3-B-GS2, ∠GS3-B-GS4; and below ground, ∠GS1-D1-GS2, ∠GS1-D1-GS4, ∠GS3-D1-GS2, ∠GS3-D1-GS4 are all less than 1°.

[0043] like Figure 3 As shown, the outer contour of the figure formed by the lines connecting the near-well point on the surface and the downhole control point to the four steel wires is a narrow and elongated special polygon (special hexagon). The polygon is B-GS1-GS3-D1-GS4-GS2-B.

[0044] Using the data processing software from Wuhan University, all distance and angle observation data from both above-ground and below-ground sources were input. The least squares principle was then applied to process and calculate the data, yielding the downhole control values. An example is shown below:

[0045]

[0046] Overall Information of Plane Control Network Adjustment Results Table

[0047] Adjustment type: Constrained adjustment

[0048] Mesh type:

[0049] Total points: 9; Known points: 2; Total number of observations: 22; Direction observations: 11; Side length observations: 11

[0050] Total number of conditions: 0; Azimuth condition number: 0; Side length condition number: 0

[0051] Total number of redundant observations: 6; Prior unit weight standard error: 0.50; Posterior unit weight standard error: 0.25

[0052] Prior accuracy for direction observation: 0.50; Prior accuracy for side length observation (A, B): 0.60, 1.00

[0053] Coordinate adjustment values ​​and their accuracy results table

[0054]

[0055] Azimuth side length adjustment values ​​and their accuracy results table

[0056]

[0057] Directional observations and their adjustment results table

[0058]

[0059] Side length observations and their adjustment results table

[0060]

[0061] 5. High measurement accuracy; can you provide experimental data? Ideally, it should be comparable to existing technologies (double-connected triangles, multi-point resection).

[0062] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A small well mouth long interval special polygon connection measurement method, characterized in that: Includes the following steps: S1. No less than four steel wires are suspended in the vertical shaft (2). A, B, and C are the ground starting points. The angles formed by each pair of steel wires with the ground near well point and the underground control point are all less than 1°. The four steel wires form a special polygon with the ground near well point and the underground control point. S2. By setting up a total station at both the ground near-well point and the underground control point, the backsight control point is used to complete the orientation. The vertical shaft (2) and the ground and underground parts (3) simultaneously perform multiple measurements on four stationary steel wires to obtain the angle and distance measurements between the four steel wires and the control point. S3. Simultaneously move and adjust the positions of the four steel wires, and re-observe to obtain the angle and distance observations between the second and third sets of steel wires and the control points. S4. Organize the data, input the coordinates of the known control points, and use the adjustment software to perform the adjustment calculation of the special polygonal connection measurement control network of the small wellhead long interval based on the principle of steel wire coordinate transfer and multi-point intersection. The adjustment calculation yields the first set of downhole control point coordinates. S5. Repeat the above steps to obtain the coordinates of the second and third sets of downhole control points. Compare the three sets of coordinates and take the average of the three sets of coordinates as the final result if the difference meets the requirements.

2. The method for measuring special polygonal connections in long intervals at small wellheads according to claim 1, characterized in that: All steel wires are fixed at the top and suspended by a 10KG lead weight 5 in the damping fluid at the bottom. The diameter of the steel wire is selected from 0.3mm to 0.5mm, which is determined based on the depth and the distance between the near well point and the steel wire. There are no less than four steel wires and the number of observations is no less than three.

3. The method for measuring special polygonal connections in long intervals at small wellheads according to claim 1, characterized in that: Both the surface near-well point and the downhole control point are forced alignment devices, which can effectively reduce alignment errors.

4. The method for measuring special polygonal connections in long intervals at small wellheads according to claim 1, characterized in that: The steel wires are distributed in pairs on both sides of the vertical shaft (2) and form a special polygon. The angles formed by the two pairs of steel wires with the ground near-well point and the downhole control point respectively meet the requirement of less than 1°.

5. The method for measuring special polygonal connections in long intervals at small wellheads according to claim 1, characterized in that: All distance measurements should be corrected for instrument multiplication constants, air pressure, and temperature and humidity. When measuring steel wires on the ground and underground, synchronization must be maintained.

6. The method for measuring special polygonal connections in long intervals at small wellheads according to claim 1, characterized in that: A, B, and C are the ground starting points, GS1, GS2, GS3, and GS4 are steel wires, and D1, D2, and D3 are downhole control points.

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