Subway protection area automatic monitoring work base point rechecking method

Abstract

According to the metro protection area automatic monitoring working base point re-checking method, a feasible positioning method is provided for station hall layer inner re-checking working base points, so that the working base point coordinate calculation difficulty is effectively reduced, and the monitoring accuracy of underground construction on the horizontal and vertical displacement of an existing structure is remarkably improved. The center point M of the top of a subway ventilation pavilion located on the ground serves as an original datum point, a coordinate transmission pier is arranged at the bottom of the subway ventilation pavilion in a station hall layer, and the center position O of the coordinate transmission pier serves as a coordinate transmission point from the ground to the station hall layer; original reference point coordinates at the top of the subway ventilation pavilion are transmitted to the center of the coordinate transmission pier to serve as a working base point for regular base point rechecking, and the total station is used for measurement on the ground and in a station hall layer respectively.

Description

Technical Field

[0001] The present application relates to the field of civil engineering monitoring, and specifically proposes a new monitoring and verification solution for implementing work base points in subway protection areas. Background Art

[0002] In recent years, with the accelerated development of urbanization and underground projects, such as subways, foundation pits and tunnel projects, many adverse effects on nearby existing building structures are inevitable during the construction process. Therefore, deformation monitoring of existing building structures is particularly important.

[0003] When monitoring existing structures, the main focus is on horizontal and vertical displacements. In particular, the monitoring of subway protection areas requires high accuracy. If the selected working base point is unstable, it will directly lead to large deviations in the monitoring data. Therefore, it is crucial to ensure the stability of the monitoring working base point.

[0004] The existing technology generally selects the subway protection zone monitoring plan at the subway structure station hall layer and the vehicle track area. Such differences are generally located underground. The elevation of the working base point in the vehicle track area can be regularly reviewed by the coordinates of the reference points in the track area, while it is extremely difficult to review the coordinates of the working base points in the station hall layer. At present, there is no public and feasible plan for reviewing the coordinates of the working base points in the station hall layer, so it is impossible to guarantee the high-precision requirements of existing structure monitoring, and there are many difficulties.

[0005] In view of this, this patent application is proposed. Summary of the invention

[0006] The method for verifying the working base points of the automated monitoring of the subway protection zone described in the present application aims to solve the problems existing in the above-mentioned prior art and to propose a feasible positioning method for verifying the working base points within the station hall layer, thereby effectively reducing the difficulty of calculating the coordinates of the working base points and significantly improving the accuracy of monitoring the horizontal and vertical displacements of existing structures during underground construction.

[0007] In order to achieve the above design objectives, the method for verifying the working base point of the subway protection zone automated monitoring takes the center point M of the top of the subway wind shelter on the ground as the original reference point, sets a coordinate transfer pier at the bottom of the subway wind shelter in the station hall, and the center position O of the coordinate transfer pier is used as the coordinate transfer point from the ground to the station hall; the coordinates of the original reference point on the top of the subway wind shelter are transferred to the center of the coordinate transfer pier as the working base point for regular base point verification, and the total station is used to measure on the ground and in the station hall respectively;

[0008] Several connection endpoints are evenly and symmetrically set on the outer diameter circumference of the coordinate transfer pier, and the distance from each connection endpoint to the center position O is the radius of the coordinate transfer pier;

[0009] A coordinate transfer ruler is connected between the connection end point and the center position O of the coordinate transfer pier to set the initial tension value;

[0010] A coordinate direction transfer compass is arranged on the top of the subway wind pavilion at the center point M connected to the coordinate transfer scale, and a mechanical sensor for measuring the forces in different directions on the coordinate direction transfer compass, a compass scale for dividing the plane of the coordinate direction transfer compass into different angles, a circular level bubble for indicating whether it is in a horizontal state, a degree calibration pointer and a fraction calibration pointer connected by a pointer rotation axis for indicating the direction in which the force is directed, and an angle reading display for indicating the angles of forces in different directions are arranged on the coordinate direction transfer compass;

[0011] In the initial state, the coordinate direction transfer compass is jointly affected by the tension of the coordinate transfer scale, and the forces in all directions are adjusted to balance in the horizontal direction; when the coordinate transfer pier is displaced, the forces in the horizontal direction are unbalanced, and the direction corresponding to the reading of the angle reading display is the force direction in the horizontal direction, that is, the offset direction of the coordinate transfer pier in the horizontal direction;

[0012] After determining the horizontal offset direction of the coordinate transfer pier, the tension between the connecting end points of the coordinate transfer scale and the coordinate transfer pier is measured as the offset.

[0013] Furthermore, the method for verifying the base point of the automated monitoring work in the subway protection zone includes the following implementation steps:

[0014] Step 1), before monitoring;

[0015] Step 1.1, select at least 4 benchmark points outside the construction impact area and determine the elevation of the benchmark points;

[0016] Step 1.2: Set up at least 4 working base points outside the construction impact area of ​​the station hall and lay out the working base point locations;

[0017] Step 1.3, select a station wind shelter for elevation transfer, place a coordinate direction transfer compass on the top of the subway wind shelter, and connect several coordinate transfer rulers to the mechanical sensors of the coordinate direction transfer compass;

[0018] Step 1.4, arrange the coordinate transfer pier vertically directly below the coordinate direction transfer compass, and ensure that the center of the coordinate transfer pier is located vertically directly below the coordinate direction transfer compass;

[0019] Step 1.5, establish a three-dimensional coordinate system with the center of the coordinate transfer pier as the coordinate origin, connect the two ends of several coordinate transfer rulers to the center of the coordinate transfer pier and several end points of the outer diameter of the coordinate transfer pier respectively, tighten the coordinate transfer rulers after the connection is completed, record the readings of each coordinate transfer ruler and calculate the triangle angle formed by each coordinate transfer ruler and the coordinate transfer pier;

[0020] Step 1.6, confirm whether the horizontal force of the coordinate transfer compass is balanced, that is, whether the angle reading display shows 0. If there is a reading, adjust the coordinate transfer ruler until the reading is cleared to zero;

[0021] Step 1.7, use the total station to measure, with the known coordinates of the working base point, measure the coordinates of the center point M on the top of the subway wind shelter, and subtract the reading of the coordinate transfer ruler between points O and M from the coordinate elevation of point M to obtain the coordinates of point O;

[0022] Step 1.8, using the coordinate value of point O, use the total station to measure the coordinate value of the working base point for monitoring in the station hall and return it to the ground reference point to complete a working base point coordinate measurement; repeat the measurement three times and calculate the average value to obtain the initial value of the working base point coordinate;

[0023] Step 2) Review during monitoring;

[0024] Step 2.1, read the reading of the angle reading display on the coordinate direction transfer compass;

[0025] Step 2.2, use a total station to measure, and obtain the coordinates of the center point M on the top of the subway wind shelter by measuring the coordinates of the known working base points;

[0026] Step 2.3, measure the tension value of the coordinate transfer ruler, and manually adjust the coordinate transfer ruler to loosen it to the initial tension value when it exceeds the initial tension value; and manually adjust the coordinate transfer ruler to tighten it to the initial tension value when it is lower than the initial tension value;

[0027] Step 2.4, read the coordinate transfer ruler;

[0028] Step 2.5, calculate the horizontal movement length and elevation change of point O to obtain the coordinate value;

[0029] Step 2.6: Use the total station to measure the coordinates of the working base point for monitoring in the station hall through the coordinates of point O and return the measurement to the ground reference point to complete the verification measurement of the working base point coordinates and obtain the coordinates of the working base point for this measurement;

[0030] Step 2.7, calculate the difference between the working base point coordinates measured this time and the initial value of the working base point coordinates, and set the upper limit of the difference according to the project situation; when the difference exceeds the upper limit, the working base point coordinates obtained by the latest measurement are used as the working base point coordinates for subsequent measurements;

[0031] Step 2.8, in the next measurement, repeat steps 2.1 to 2.5 to obtain the position movement of point O relative to the last measurement, and then obtain the coordinates of point O this time;

[0032] Repeat steps 2.6 to 2.7 to obtain the coordinates of the base point for this operation.

[0033] In summary, the advantage of the automated monitoring work base point review method for the subway protection zone proposed in this application is that it provides an effective work base point review plan within the station hall layer, which is relatively accurate in base point review and simple to operate, thereby effectively ensuring the accuracy of the horizontal and vertical displacement monitoring data of the existing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present application is now further described in conjunction with the following drawings;

[0035] Figure 1 This is a schematic diagram of transferring the coordinates of the top reference point of the subway wind shelter located on the ground to the station hall level;

[0036] Figure 2 Pass the compass diagram for the coordinate direction;

[0037] Figure 3 Schematic diagram of ruler connection points for coordinate transfer;

[0038] Figure 4 It is a schematic diagram of calculation of the starting section with △ABM in the initial and measured states;

[0039] Figure 5 Schematic diagram for calculating the angles of △NB1B2;

[0040] Figure 6 The schematic diagram of calculating the plane moving length and elevation change of the transfer point in the station hall layer through △NB1B2;

[0041] Figure 7 It is a schematic diagram of the correction of the plane coordinate angle of the transfer point in the station hall layer;

[0042] In the above drawings, 1. compass scale; 2. circular level bubble; 3. pointer rotation axis; 4. degree calibration pointer; 5. fraction calibration pointer; 6. angle reading display; 7. mechanical sensor; 10. top of subway wind shelter; 20. coordinate transfer pier; DETAILED DESCRIPTION

[0043] In order to further explain the technical means adopted by the present application to achieve the predetermined design objectives, the following preferred implementation scheme is proposed in conjunction with the accompanying drawings.

[0044] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] Embodiment 1, as Figures 1 to 7 As shown, the automatic monitoring work base point verification method for the subway protection zone proposed in this application is based on the elevation transfer method, and the center point M of the top 10 of the subway wind pavilion on the ground is used as the original reference point. The original reference point is located outside the influence range of the underground construction and has a relatively stable characteristic;

[0046] Correspondingly, a coordinate transfer pier 20 is set at the bottom of the subway wind shelter in the station concourse layer, and the original reference point coordinates of the subway wind shelter top 10 are transferred to the center of the coordinate transfer pier 20 as the working base point for regular base point review. Total stations are used to measure on the ground and in the station concourse layer respectively to obtain the precise coordinate values ​​of the working base point, thereby ensuring the accuracy of subsequent working base point coordinate review.

[0047] The center position O of the coordinate transfer pier 20 is used as the coordinate transfer point from the ground to the station hall level;

[0048] A total of 8 connection endpoints A, B, C, D, E, F, G, and H are set on the outer diameter circumference of the coordinate transfer pier 20. The angle between two adjacent connection endpoints is 45°, and the distance from each connection endpoint to the center position O is the radius of the coordinate transfer pier 20.

[0049] The eight connection ends of the coordinate transfer pier 20 and the center position O are respectively connected with a coordinate transfer ruler, and the tension data between the coordinate transfer ruler and each connection end of the coordinate transfer pier 20 can be measured, and the initial tension value is set to 100N;

[0050] A coordinate direction transfer compass is arranged on the top 10 of the subway wind pavilion and at the center point M connected to the coordinate transfer scale. The coordinate direction transfer compass is provided with a mechanical sensor 7 for measuring the forces in different directions on the coordinate direction transfer compass, a compass scale 1 for dividing the plane of the coordinate direction transfer compass into 360°, a circular level bubble 2 for indicating whether it is in a horizontal state, a degree calibration pointer 4 and a fraction calibration pointer 5 connected by a pointer rotation axis 3 for indicating the direction in which the force is directed, and an angle reading display 6 for indicating the angles of forces in different directions, for example, the force in the due north direction is calibrated as 0°, the force in the due east direction is calibrated as 90°, etc.;

[0051] In the initial state, the coordinate direction transfer compass is jointly affected by the pulling force of the 9 coordinate transfer rulers, and the forces in all directions are adjusted to balance in the horizontal direction. At this time, the angle reading display 6 on the coordinate direction transfer compass should be 0; when the coordinate transfer pier 20 is displaced, the forces in the horizontal direction are unbalanced, and the angle reading display 6 should show a reading greater than 0. The direction corresponding to this reading is the force direction in the horizontal direction, that is, the offset direction of the coordinate transfer pier 20 in the horizontal direction;

[0052] In the station hall layer, the changes of the station hall layer in a small range caused by the construction are basically the same, and the coordinate transfer pier 20 is a whole, and the overall change trend is the same, so the position change of the center position O of the coordinate transfer pier 20 should be the same as that of the other positions;

[0053] After determining the horizontal offset direction of the coordinate transfer pier 20, the tension between the coordinate transfer ruler and the connecting end point of the coordinate transfer pier 20 is measured as the offset; specifically, when the tension exceeds 100N, the coordinate transfer ruler is manually adjusted to be loosened to 100N, and when it is less than 100N, the coordinate transfer ruler is manually adjusted to be tightened to 100N, and the reading on the coordinate transfer ruler is read to calculate the offset;

[0054] For example, Figure 4 As shown, a schematic comparison of the cross section formed between the A and B2 connection endpoints on the coordinate transfer pier 20 and the center point M of the subway wind shelter top 10 is shown; wherein, the initial state is △A1B1M and the measurement state is △A2B2M.

[0055] Since A1B1 and MB2 intersect at point N, let the length of line segment B2N be a, the length of line segment MN be b, the length of line segment B1N be c, the length of line segment A1N be d, let ∠MA1B1 be ∠1, ∠MB1A1 be ∠2, ∠A1NM be ∠α, ∠A1MB2 be ∠β, ∠B1NM be ∠γ, ∠B1MB2 be ∠δ, and ∠B1NB2 be ∠θ.

[0056] like Figure 5 The process of calculating the sides and angles of △NB1B2 is shown in the figure. In △B1NB2, the length of line segment B2N is a, the length of line segment B1N is c, the length of line segment B1B2 is e, ∠B2NB1 is ∠θ, ∠B2B1N is ∠μ, and ∠B1B2N is ∠λ.

[0057] like Figure 6 As shown, the plane moving length and elevation change of the transfer point in the station hall layer are calculated through △NB1B2. In △B1NB2, a perpendicular line is made from B2 to B1N, and the foot of the perpendicular is P. The vertical component z is the elevation change of the coordinate transfer scale B, and the horizontal component f is the plane moving length of the coordinate transfer scale B. In △B1PB2, the length of line segment B1B2 is e, the length of line segment B2P is z, the length of line segment B1P is f, ∠B2PB1 is a right angle, ∠B2B1P is ∠μ, and ∠B1B2P is ∠υ.

[0058] Based on the above design concept, the subway protection zone automated monitoring work base point review method proposed in this application includes the following implementation steps:

[0059] Step 1), before monitoring;

[0060] Step 1.1, select at least 4 benchmark points outside the construction impact area and determine the elevation of the benchmark points;

[0061] Step 1.2: Set up at least 4 working base points outside the construction impact area of ​​the station hall and lay out the working base point locations;

[0062] Step 1.3, select a station wind shelter for elevation transfer, arrange a coordinate direction transfer compass on the top 10 of the subway wind shelter, and connect 9 coordinate transfer rulers to the mechanical sensor 7 of the coordinate direction transfer compass;

[0063] Step 1.4, arrange the coordinate transfer pier 20 vertically directly below the coordinate direction transfer compass, and ensure that the center of the coordinate transfer pier 20 is located vertically directly below the coordinate direction transfer compass;

[0064] Step 1.5, establish a three-dimensional coordinate system with the center of the coordinate transfer pier 20 as the coordinate origin, connect the two ends of the 9 coordinate transfer rulers to the center of the coordinate transfer pier 20 and the 8 endpoints of the outer diameter of the coordinate transfer pier, and connect one endpoint every 45°. After the connection is completed, tighten the coordinate transfer rulers, record the readings of each coordinate transfer ruler, and calculate the angle of the triangle formed by each coordinate transfer ruler and the coordinate transfer pier 20;

[0065] Step 1.6, confirm whether the force on the coordinate direction transfer compass in the horizontal direction is balanced, that is, whether the angle reading display 6 shows 0. If there is a reading, adjust the coordinate transfer ruler until the reading is cleared to zero;

[0066] Step 1.7, use the total station to measure, with the known coordinates of the working base point, measure the coordinates of the center point M at the top of the subway wind shelter 10, and subtract the reading of the coordinate transfer ruler between point O and point M from the coordinate elevation of point M to obtain the coordinates of point O;

[0067] Step 1.8, using the coordinate value of point O, use the total station to measure the coordinate value of the working base point for monitoring in the station hall and return it to the ground reference point to complete a working base point coordinate measurement; repeat the measurement three times and calculate the average value to obtain the initial value of the working base point coordinate;

[0068] Step 2) Review during monitoring;

[0069] Step 2.1, reading the reading of the angle reading display 6 on the coordinate direction transfer compass;

[0070] Step 2.2, use a total station to measure, and obtain the coordinates of the center point M on the top 10 of the subway wind shelter by measuring the coordinates of the known working base points;

[0071] Step 2.3, measure the tension value of the coordinate transfer ruler. When it exceeds 100N, manually adjust the coordinate transfer ruler to loosen it to 100N. When it is less than 100N, manually adjust the coordinate transfer ruler to tighten it to 100N.

[0072] Step 2.4, read the coordinate transfer ruler;

[0073] Taking the example that the degree calibration pointer 4 on the coordinate direction transfer compass points to the coordinate transfer scale B, the coordinate transfer scales B, O, and A are in the same plane, and the readings of the coordinate transfer scales A, B, and O are read;

[0074] Step 2.5, calculate the horizontal movement length and elevation change of point O to obtain the coordinate value;

[0075] The initial state position is A1, B1, the current state position is A2, B2, establish △MA1B1 and △MA2B2, project △MA2B2 into the plane of △MA1B1, calculate the plane moving length and elevation change of the transfer point O in the station, as follows: Figures 4 to 7 As shown, the calculation process is as follows:

[0076] Line segment MA1, line segment MB1, line segment A1B1, ∠1 and ∠2∠A1MB1 are read and calculated in the initial state and are all known.

[0077] From the sine theorem we can get: The sum of the lengths of c and d is the length of line segment A1B1, and the sum of ∠β and ∠δ is ∠A1MB1, so we can get:

[0078]

[0079] There are 8 equations in total, 7 of which have unknown parameters. By solving all the unknown parameters, we can get the lengths of b and c and the angle ∠α.

[0080] ∠α and ∠θ are opposite angles, so ∠θ = ∠α. The sum of the lengths of a and b is equal to the length of line segment MB2. The length of line segment MB2 is known, so the length of a can be obtained. Therefore, in △B1NB2, according to the sine theorem, we can get:

[0081] Then we can get three equations, among which there are three unknown parameters, and the solutions of all the unknown parameters can be obtained.

[0082]

[0083] In △B1NB2, draw a perpendicular line to B1N with B2 as the starting point, and the foot of the perpendicular is P. The vertical component z is the elevation change of the coordinate transfer scale B, and the horizontal component f is the projection of the movement length of the coordinate transfer scale B in the plane direction.

[0084] In the right triangle B1B2P, z = sin ∠μ × e, f = cos ∠μ × e.

[0085] According to the coordinate direction, the compass scale is transferred, and the reading of the OB direction at the dial is 90°. Let the absolute value of the difference between the reading displayed on the angle reading display and 90° be ∠ω, such as Figure 7 As shown, a right triangle is established to perform angle correction calculation, and the moving length of the real coordinate transfer scale B in the plane direction is g, g = f / cos∠ω.

[0086] The vertical and plane moving lengths of the coordinate transfer ruler B can be obtained, and the plane offset angle can be obtained by the coordinate direction transfer compass reading. The change of the coordinate transfer ruler O is the same as B. Therefore, the change of the coordinate transfer ruler O can be obtained, and then the O coordinate can be obtained.

[0087] Step 2.6: Use the total station to measure the coordinates of the working base point for monitoring in the station hall through the coordinates of point O and return the measurement to the ground reference point to complete the verification measurement of the working base point coordinates and obtain the coordinates of the working base point for this measurement;

[0088] Step 2.7, calculate the difference between the working base point coordinates measured this time and the initial value of the working base point coordinates, and set the upper limit of the difference according to the project situation; when the difference exceeds the upper limit, the working base point coordinates obtained by the latest measurement are used as the working base point coordinates for subsequent measurements;

[0089] Step 2.8, in the next measurement, repeat steps 2.1 to 2.5 to obtain the position movement of point O relative to the last measurement, and then obtain the coordinates of point O this time;

[0090] Repeat steps 2.6 to 2.7 to obtain the coordinates of the base point for this operation.

[0091] As described above, similar technical solutions can be derived from the solutions given in the drawings and descriptions. However, any solution content that does not deviate from the structure of the present invention still belongs to the scope of rights of the technical solution of this application.

Claims

1. A method for verifying the base point of automated monitoring work in a subway protection zone, characterized in that: The center point M of the top of the subway wind shelter on the ground is used as the original reference point, and a coordinate transfer pier is set at the bottom of the subway wind shelter in the station hall. The center position O of the coordinate transfer pier is used as the coordinate transfer point from the ground to the station hall; the coordinates of the original reference point on the top of the subway wind shelter are transferred to the center of the coordinate transfer pier as the working base point for regular base point verification, and the total station is used to measure on the ground and in the station hall respectively; Several connection endpoints are evenly and symmetrically set on the outer diameter circumference of the coordinate transfer pier, and the distance from each connection endpoint to the center position O is the radius of the coordinate transfer pier; A coordinate transfer ruler is connected between the connection end point and the center position O of the coordinate transfer pier to set the initial tension value; A coordinate direction transfer compass is arranged on the top of the subway wind pavilion at the center point M connected to the coordinate transfer scale, and a mechanical sensor for measuring the forces in different directions on the coordinate direction transfer compass, a compass scale for dividing the plane of the coordinate direction transfer compass into different angles, a circular level bubble for indicating whether it is in a horizontal state, a degree calibration pointer and a fraction calibration pointer connected by a pointer rotation axis for indicating the direction in which the force is directed, and an angle reading display for indicating the angles of forces in different directions are arranged on the coordinate direction transfer compass; In the initial state, the coordinate direction transfer compass is jointly affected by the tension of the coordinate transfer scale, and the forces in all directions are adjusted to balance in the horizontal direction; when the coordinate transfer pier is displaced, the forces in the horizontal direction are unbalanced, and the direction corresponding to the reading of the angle reading display is the force direction in the horizontal direction, that is, the offset direction of the coordinate transfer pier in the horizontal direction; After determining the horizontal offset direction of the coordinate transfer pier, the tension between the connecting end points of the coordinate transfer scale and the coordinate transfer pier is measured as the offset.

2. The method for verifying the base point of automated monitoring work in a subway protection zone according to claim 1 is characterized by: The implementation steps include: Step 1), before monitoring; Step 1.1, select at least 4 benchmark points outside the construction impact area and determine the elevation of the benchmark points; Step 1.2: Set up at least 4 working base points outside the construction impact area of ​​the station hall and lay out the working base point locations; Step 1.3, select a station wind shelter for elevation transfer, place a coordinate direction transfer compass on the top of the subway wind shelter, and connect several coordinate transfer rulers to the mechanical sensors of the coordinate direction transfer compass; Step 1.4, arrange the coordinate transfer pier vertically directly below the coordinate direction transfer compass, and ensure that the center of the coordinate transfer pier is located vertically directly below the coordinate direction transfer compass; Step 1.5, establish a three-dimensional coordinate system with the center of the coordinate transfer pier as the coordinate origin, connect the two ends of several coordinate transfer rulers to the center of the coordinate transfer pier and several end points of the outer diameter of the coordinate transfer pier respectively, tighten the coordinate transfer rulers after the connection is completed, record the readings of each coordinate transfer ruler and calculate the triangle angle formed by each coordinate transfer ruler and the coordinate transfer pier; Step 1.6, confirm whether the horizontal force of the coordinate transfer compass is balanced, that is, whether the angle reading display shows 0. If there is a reading, adjust the coordinate transfer ruler until the reading is cleared to zero; Step 1.7, use the total station to measure, with the known coordinates of the working base point, measure the coordinates of the center point M on the top of the subway wind shelter, and subtract the reading of the coordinate transfer ruler between points O and M from the coordinate elevation of point M to obtain the coordinates of point O; Step 1.8, using the coordinate value of point O, use the total station to measure the coordinate value of the working base point for monitoring in the station hall and return it to the ground reference point to complete a working base point coordinate measurement; repeat the measurement three times and calculate the average value to obtain the initial value of the working base point coordinate; Step 2) Review during monitoring; Step 2.1, read the reading of the angle reading display on the coordinate direction transfer compass; Step 2.2, use a total station to measure, and obtain the coordinates of the center point M on the top of the subway wind shelter by measuring the coordinates of the known working base points; Step 2.3, measure the tension value of the coordinate transfer ruler, and manually adjust the coordinate transfer ruler to loosen it to the initial tension value when it exceeds the initial tension value; and manually adjust the coordinate transfer ruler to tighten it to the initial tension value when it is lower than the initial tension value; Step 2.4, read the coordinate transfer ruler; Step 2.5, calculate the horizontal movement length and elevation change of point O to obtain the coordinate value; Step 2.6: Use the total station to measure the coordinates of the working base point for monitoring in the station hall through the coordinates of point O and return the measurement to the ground reference point to complete the verification measurement of the working base point coordinates and obtain the coordinates of the working base point for this measurement; Step 2.7, calculate the difference between the working base point coordinates measured this time and the initial value of the working base point coordinates, and set the upper limit of the difference according to the project situation; when the difference exceeds the upper limit, the working base point coordinates obtained by the latest measurement are used as the working base point coordinates for subsequent measurements; Step 2.8, in the next measurement, repeat steps 2.1 to 2.5 to obtain the position movement of point O relative to the last measurement, and then obtain the coordinates of point O this time; Repeat steps 2.6 to 2.7 to obtain the coordinates of the base point for this operation.

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