Accurate determination method and special tool for cutting line of cross brace between steel pipe piles

Abstract

The application discloses a precise measuring method and special tool for cutting line of cross support between steel pipe piles, and the method comprises the following steps: marking the design elevation of the cross support on two steel pipe piles; determining the center of the cross support on the two steel pipe piles by the centroid scale based on the design elevation; determining the installation position of the positioning device based on the center of the cross support and installing the positioning device on the two steel pipe piles; respectively reading the horizontal distance between the two steel pipe piles at each corresponding position and the horizontal distance between the positioning device on one side and the steel pipe pile on the side; laying out the top surface reference line parallel to the axis of the cross support to be cut on the cross support by the top line scale; transferring the distance value of the measured horizontal distance to the top surface reference line according to the corresponding angle by the plastic plate ruler and marking a plurality of control points; and connecting the plurality of control points into a smooth curve, which is the cutting line of the cross support.

Description

Technical Field

[0001] This invention relates to the field of hydraulic engineering construction technology, specifically to a method and special tool for accurately determining the cutting line of the cross bracing between steel pipe piles. Background Technology

[0002] As high-pile wharves develop towards larger spans, the free length of steel pipe piles, as foundation load-bearing components, exposed above ground is constantly increasing. To improve the bending stability and overall bearing capacity of the pile foundation, the design often employs the method of adding steel cross braces between piles to effectively reduce the free length of the steel pipe piles. However, during pile driving, steel pipe piles inevitably experience planar position deviations or vertical tilts, resulting in uncertainties in the spatial distance and relative angle between two steel pipe piles. Therefore, the existing method of calculating the cross brace length and laying out the cutting line simply by measuring the straight-line distance between the two piles ignores the inclination and cross-sectional shape of the pile body. This leads to poor fit between the cut cross brace ends and the pile body, resulting in the need for extensive secondary cutting corrections on-site. Uneven weld width not only increases construction costs but also seriously affects the welding quality of joint connections.

[0003] In summary, there is an urgent need in this field for a method that can accurately determine the cutting line of the cross bracing between steel pipe piles, so that the actual lengths of the cut cross bracing piles match, and can reduce construction costs. Summary of the Invention

[0004] The purpose of this invention is to provide a precise method for determining the cutting line of the cross bracing between steel pipe piles, aiming to solve the technical problems in the prior art where the cross bracing cutting is inaccurate due to the misalignment of the steel pipe piles and the large amount of on-site installation and adjustment is required. At the same time, another purpose of this invention is to provide a special measuring tool for the above-mentioned determination method, so as to improve the accuracy and efficiency of on-site layout.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for accurately determining the cutting line of the cross bracing between steel pipe piles, comprising the following steps: Mark the design elevation of the cross bracing on the two steel pipe piles; Using the design elevation as a reference, the center of the cross brace is determined on the two steel pipe piles using a centroid measuring ruler; The installation position of the positioning device is determined with the center of the cross brace as a reference, and the positioning device is installed on the two steel pipe piles. Place the two ends of the ranging device in sequence at the preset angle positions on the positioning device, and read the horizontal distance between the two steel pipe piles at each corresponding position and the horizontal distance between the positioning device on one side and the steel pipe pile on that side. Using a top-line measuring ruler, mark out a top surface reference line parallel to the axis of the cross brace to be cut; The measured horizontal distance values ​​are transferred to the top surface baseline according to the corresponding angle using a plastic ruler, and multiple control points are marked. Connecting multiple control points into a smooth curve forms the cutting line of the cross brace.

[0006] In some embodiments, the specific process of determining the center of the cross brace on the two steel pipe piles based on the design elevation is as follows: Place the straightedge of the centroid measuring ruler against the pile wall of the two steel pipe piles, so that the top surface of the straightedge is flush with the design elevation line. Move the two sliding rulers in the centroid measuring scale to a position that is close to the two steel pipe piles and keep them horizontal; Draw a vertical line on the sliding ruler at a value equal to the radius of the steel pipe pile. The intersection of this vertical line and the design elevation line is the center of the horizontal brace.

[0007] In some embodiments, the specific process of determining the installation position of the positioning device based on the center of the cross brace and installing the positioning device on the two steel pipe piles is as follows: Place one side of the ruler close to the center of the cross brace and keep the ruler in a vertical position. Determine the hanging points of the upper and lower magnets on the steel pipe pile according to the diameter of the positioning ring in the positioning device and with the center of the cross brace as the center of symmetry. The two magnets are attached to the two designated hanging points on the steel pipe pile, one above the other. The two ends of the positioning ring are bolted to two magnets.

[0008] In some embodiments, the specific process of laying out a top surface reference line parallel to the axis of the cross brace on the cross brace to be cut is as follows: Place the top line measuring ruler at both ends of the cross brace and fit it tightly against the cross brace with the limiting block. The intersection of the gaps between the vertical slits of the two top line measuring rulers and the top of the cross brace are the two vertices. Draw a line between these two vertices to form the top surface reference line of the cross brace axis.

[0009] In some embodiments, the specific process of transferring the measured horizontal distance value to the top surface baseline according to the corresponding angle and marking multiple control points is as follows: Mark the maximum horizontal distance between one of the positioning devices and the steel pipe pile on that side on the cross brace; Place the left side of the plastic ruler against the marked maximum value and wrap the plastic ruler around the cross brace so that the seam of the plastic ruler coincides with the top baseline of the cross brace. The measuring device is placed at different angles marked on the plastic ruler, and the horizontal distance between the two steel pipe piles at each corresponding position is marked on the steel pipe pile. Then, the multiple intersection points between the two endpoints of the measuring device and the two steel pipe piles are multiple control points.

[0010] In a second aspect, the present invention provides a dedicated tool for implementing the method provided in the first aspect, comprising: Centroid measuring ruler is used to determine the center of the cross brace on steel pipe piles; A positioning device is fixed on the steel pipe pile with the center of the cross brace as the center of symmetry, and is used to control the accurate position of the measuring point. The ranging device has its two ends respectively attached to the positioning devices of the two steel pipe piles, and is used to measure the straight distance between the two positioning devices in different angular directions; The top line measuring ruler is attached to both ends of the cross brace to be cut and is used to lay out the baseline of the top surface on the cross brace to be cut. A plastic ruler is wrapped around both ends of the cross brace to be cut, serving as a template for angle marking and data transfer.

[0011] In some embodiments, the centroid measuring scale includes a straightedge and a sliding scale, the sliding scale being mounted on the straightedge and movable on the straightedge, and the sliding scale being provided with graduation lines.

[0012] In some embodiments, the positioning device includes a magnetic hanger and a positioning ring. The magnetic hanger is attached to the outer wall of the steel pipe pile, and the two ends of the positioning ring are respectively connected to the two magnetic hangers by bolts.

[0013] In some embodiments, the ranging device includes an outer tube and an inner tube, the inner tube being retractably inserted into the outer tube, and scale lines being provided on the surfaces of both the outer tube and the inner tube, with the starting directions of the two scale lines being opposite, and the sum of their readings being the total length to be measured.

[0014] In some embodiments, the top line measuring ruler includes a horizontal ruler, a vertical slit ruler, and limiting blocks. The horizontal ruler is provided with a leveling bubble for leveling. The vertical slit ruler is vertically fixed to the middle of the horizontal ruler. The two limiting blocks are provided at both ends of the horizontal ruler for contacting and positioning the outer wall of the cross brace.

[0015] Compared with the prior art, the beneficial effects of the present invention mainly include: This invention provides a precise method for determining the cutting line of the cross brace between steel pipe piles. By establishing a unified measurement benchmark and combining multi-angle distance measurements, it transforms the complex problem of spatial intersection line cutting into a planar layout problem. This eliminates measurement errors caused by the tilt and deformation of the steel pipe piles, resulting in a high-precision cutting line. This ensures the fit between the cross brace and the pile wall, reduces on-site correction work, and guarantees weld quality and structural performance. Furthermore, the invention provides a cleverly designed specialized measuring tool with clear steps for combined use, making it easy for on-site construction personnel to master. It requires no complex calculations, improving construction efficiency. Moreover, for steel pipe piles of different diameters, only the corresponding positioning ring and plastic ruler need to be replaced, demonstrating good versatility. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the embodiments will be briefly described below: Figure 1 This is a schematic flowchart of the determination method described in this invention; Figure 2 This is a schematic diagram illustrating the usage process of the centroid measuring ruler described in this invention; Figure 3 This is a schematic diagram illustrating the determination of the center of the cross brace and the determination of the magnet hanging point as described in this invention; Figure 4 This is a schematic diagram of the positioning device of the present invention installed on a steel pipe pile; Figure 5 This is a schematic diagram of the ranging device described in this invention installed on the positioning device; Figure 6 This is a schematic diagram of the top line measuring ruler described in this invention; Figure 7 This is a schematic diagram of the top line measuring ruler of the present invention installed on the cross brace to determine the snap line; Figure 8 This is a schematic diagram of the cutting line of the cross brace to be cut according to the present invention; Figure 9 This is a schematic diagram of the pre-cut cross brace of the present invention installed on the steel pipe pile.

[0017] As shown in the figure: 100. Special tools; 110. Centroid measuring ruler; 111. Straight ruler; 112. Sliding ruler; 120. Positioning device; 121. Positioning ring; 122. Magnetic hanger; 123. Hanging lug; 124. Positioning stake; 130. Distance measuring device; 131. Outer tube; 132. Inner tube; 140. Top line measuring ruler; 141. Level ruler; 142. Vertical seam ruler; 143. Limiting block; 150. Plastic ruler. 200. Horizontal brace; 300. Steel pipe piles. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Currently, to improve the bearing capacity of high-pile foundations, the design employs the method of adding steel cross braces between piles to reduce the free length of the piles, thereby reducing the length of the compression members and improving the stability of the pile foundation. However, due to the potential for misalignment and tilting of steel pipe piles during pile driving, the spatial distance between the steel pipe piles is uncertain. In such cases, simply calculating the length of the cross brace and the cutting line by measuring the straight-line distance between two piles often results in significant deviations, leading to a large amount of on-site cutting and consequently increasing construction costs.

[0020] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for accurately determining the cutting line of the cross bracing between steel pipe piles, such as... Figure 1 As shown, it includes the following steps: Step S1: Mark the design elevation of the cross brace 200 on the two steel pipe piles 300. Step S2: Using the design elevation as a reference, determine the center O of the cross brace 200 on the two steel pipe piles 300 using a centroid measuring ruler 110; Step S3: Determine the installation position of the positioning device 120 based on the center O of the cross brace 200 and install the positioning device 120 on the two steel pipe piles 300. Step S4: Place the two ends of the ranging device 130 at the preset angle positions on the positioning device 120 in sequence, and read the horizontal distance between the two steel pipe piles 300 at each corresponding position and the horizontal distance between the positioning device 120 on one side and the steel pipe pile 300 on that side. Step S5: Using the top line measuring ruler 140, a top surface reference line L parallel to the axis of the cross brace 200 is laid out on the cross brace 200 to be cut. Step S6: Using a plastic ruler 150, the measured horizontal distance value is transferred to the top surface reference line L according to the corresponding angle, and multiple control points are marked. Step S7: Connect the multiple control points into a smooth curve, which is the cutting line of the cross brace 200.

[0021] By using the measurement method provided by this invention, a unified measurement benchmark is established and multi-angle distance measurement is combined to transform the complex spatial intersection line cutting problem into a planar layout problem. This eliminates the measurement errors caused by the inclination and deformation of the steel pipe pile, resulting in a higher accuracy of the cutting line. This ensures the fit between the cross brace 200 and the steel pipe pile 300 wall, reduces the amount of on-site correction work, and also ensures the weld quality and structural stress performance.

[0022] The measurement method described in this invention will be further described in detail below.

[0023] Combination Figure 2 and Figure 3 As shown, in step S1, the design elevation line M of the cross brace 200 is marked on the two steel pipe piles 300 using a level.

[0024] Step S2: Using the design elevation line M as a reference, determine the center of the cross brace 200 on the two steel pipe piles 300 using a centroid measuring ruler 110. The specific process is as follows: Step S21: Place the straightedge 111 in the centroid measuring ruler 110 against the pile wall of the two steel pipe piles 300, so that the top surface of the straightedge 111 is flush with the design elevation line M. Step S22: Move the two sliding rulers 112 in the centroid measuring ruler 110 to a position that is close to the two steel pipe piles 300 and keep them horizontal; Step S23: Draw a vertical line on the sliding ruler 112 at a point with the same radius as the steel pipe pile 300. The intersection of this vertical line and the design elevation line M is the center O of the cross brace 200.

[0025] Combination Figure 4 As shown, in step S3, the process of determining the installation position of the positioning device 120 based on the center O of the cross brace 200 and installing the positioning device 120 on the two steel pipe piles 300 is as follows: Step S31: Place one side of the ruler close to the center O of the cross brace 200 and keep the ruler in a vertical state. Determine the hanging points A of the upper and lower magnet hangers 122 on the steel pipe pile 300 with the center O of the cross brace 200 as the center of symmetry according to the diameter of the positioning ring 121 in the positioning device 120. That is, the distance between the hanging point A of the magnet hanger 122 and the center O of the cross brace 200 is equal to the radius of the positioning ring 121. Step S32: Attach the two magnets 122 to the two designated hanging points A on the steel pipe pile 300, respectively. Step S33: The two ends of the positioning ring 121 are connected to the lugs 123 by bolts, and the positioning ring 121 is connected to the two magnet hangers 122. The verticality of the positioning ring 121 can be adjusted by adjusting the depth of the bolt rotation to make it vertical.

[0026] Combination Figure 5 As shown, in step S4, the two ends of the ranging device 130 are placed sequentially at preset angles on the positioning device 120, and the horizontal distance between the two steel pipe piles 300 at each corresponding position and the horizontal distance between the positioning device 120 on one side and the steel pipe pile 300 on that side are read respectively. In this step, specifically, the two ends of the ranging device 130 are placed in the control piles 124 at corresponding angles of the two positioning rings 121, and the degree of the ranging device 130 at each different angle (that is, the horizontal distance between the two positioning rings 121) and the horizontal distance between the left positioning ring 121 and the steel pipe pile 300 on that side are measured respectively.

[0027] Combination Figure 6 and Figure 7 As shown, step S5, the specific process of laying out the top surface reference line L parallel to the axis of the cross brace 200 on the cross brace 200 to be cut, is as follows: Step S51: Place the top line measuring ruler 140 at both ends of the cross brace 200 and press it tightly against the outer wall of the cross brace 200 through the limiting block 143. The intersection of the gaps of the vertical slit rulers 142 of the two top line measuring rulers 140 with the top of the cross brace 200 is the two vertices. A line is drawn between the two vertices to form the top surface reference line L of the axis of the cross brace 200.

[0028] Combination Figure 8 As shown, step S6, the specific process of transferring the measured horizontal distance value to the top surface baseline L according to the corresponding angle and marking multiple control points, is as follows: Step S61: Mark the maximum horizontal distance between one of the positioning devices 120 (specifically the positioning ring 121) and the steel pipe pile 300 on the cross brace 200. Step S62: Place the left side of the plastic ruler 150 close to the marked maximum value and wrap the cross brace 200 with the plastic ruler 150 so that the seam of the plastic ruler 150 coincides with the top surface reference line L of the cross brace 200. Step S63: Place the distance measuring device 130 at different angles marked on the plastic ruler 150 and mark the horizontal distance between the two steel pipe piles 300 at each corresponding position on the steel pipe piles 300. Then, the multiple intersections between the two endpoints of the distance measuring device 130 and the two steel pipe piles 300 are multiple control points. Step S7: Connecting the multiple control points into a smooth curve forms the cutting line of the cross brace 200. After cutting the cross brace 200 using the measurement method provided by this invention, the cross brace 200 is installed between the two steel pipe piles 300. All fittings meet the accuracy requirements. The assembled cross brace 200 is as follows: Figure 9 As shown.

[0029] Secondly, the present invention also provides a special tool 100 for implementing the above-mentioned measurement method, including a centroid measuring ruler 110, a positioning device 120, a distance measuring device 130, a top line measuring ruler 140, and a plastic ruler 150. The centroid measuring ruler 110 is used to determine the center O of the cross brace 200 on the steel pipe pile 300; the positioning device 120 is fixed on the steel pipe pile 300 with the center O of the cross brace 200 as the center of symmetry, and is used to control the accurate position of the measuring point; the two ends of the distance measuring device 130 are respectively engaged with the positioning devices 120 of the two steel pipe piles 300, and are used to measure the straight distance between the two positioning devices 120 in different angular directions; the top line measuring ruler 140 abuts against the two ends of the cross brace 200 to be cut, and is used to lay out the reference line L of the top surface on the cross brace 200 to be cut; the plastic ruler 150 covers the two ends of the cross brace 200 to be cut, and serves as a template for angle laying and data transfer.

[0030] The present invention provides a special tool 100, which is ingeniously designed and has clear steps when used in combination. It is easy for on-site construction personnel to master, requires no complicated calculations, and improves construction efficiency. Moreover, for steel pipe piles of different diameters, only the corresponding positioning ring and plastic ruler need to be replaced, which has good versatility.

[0031] Furthermore, the centroid measuring scale 110 includes a hollow straightedge 111 and a sliding scale 112 made of aluminum alloy. The sliding scale 112 is mounted on the straightedge 111 and can move on the straightedge 111. The sliding scale 112 is provided with scale lines for reading the diameter or radius value of the positioning ring 121.

[0032] Furthermore, the positioning device 120 includes a magnetic positioning ring 121, a magnetic hanger 122, a hanging ear 123, and a control post 124. The positioning ring 121 is a circular ring structure made of hollow aluminum alloy tube, and the diameter of its inner circle is the same as the diameter of the cross brace 200. The positioning ring 121 is provided with arc angle scales at 15-degree intervals. The inner side of the positioning ring 121 is provided with an aluminum alloy control post 124 for controlling the accurate position of the ranging device 130 during ranging. The hanging ear 123 is welded to the outer side of the positioning ring 121 at 0 degrees and 180 degrees. A bolt is inserted into the hanging ear 123, and the bolt can only rotate in the hole of the hanging ear 123. The magnetic hanger 122 is adsorbed onto the outer wall of the steel pipe pile 300. The two ends of the positioning ring 121 are respectively connected to the two magnetic hangers 122 through the bolts of the hanging ear 123.

[0033] Furthermore, the magnet hanger 122 is a neodymium magnet with a screw hole in the center. Its adsorption force with the steel plate is controlled at about 10 kg, which can stably adhere to the outer wall of the steel pipe pile 300.

[0034] Furthermore, the ranging device 130 includes an outer tube 131 and an inner tube 132. The inner tube 132 is telescopically inserted into the outer tube 131. The surfaces of the outer tube 131 and the inner tube 132 are provided with scale lines, and the starting directions of the two scale lines are opposite. The sum of their readings is the total length to be measured.

[0035] Furthermore, the top line measuring ruler 140 includes a horizontal ruler 141, a vertical slit ruler 142, and limiting blocks 143. The horizontal ruler 141, the vertical slit ruler 142, and the limiting blocks 143 are all made of aluminum alloy. The horizontal ruler 141 is provided with a leveling bubble for leveling. The vertical slit ruler 142 is vertically fixed to the middle of the horizontal ruler 141. The two limiting blocks 143 are located at both ends of the horizontal ruler 141 for contacting and positioning the outer wall of the cross brace 200. The net distance between the two limiting blocks 143 should be less than the diameter of the cross brace 200. There is a 1-2mm gap in the middle of the vertical slit ruler 142. The vertical slit ruler 142 is perpendicular to the horizontal ruler 141, and the linear center of the vertical slit ruler 142 is located at the center of the two limiting blocks 143.

[0036] Furthermore, the plastic ruler 150 is made of a plastic sheet with good elasticity and is rectangular. Its length is equal to the outer perimeter of the cross brace 200, and its width is generally one-fifth to one-quarter of its length. The thickness of the plastic sheet is about 1mm. A plastic handle is glued to the edge of the plastic sheet along its length to facilitate on-site operation by the operator. The plastic sheet is provided with arc angle marking lines.

[0037] In summary, this invention provides a precise method for determining the cutting line of the cross brace between steel pipe piles. By establishing a unified measurement benchmark and combining multi-angle distance measurements, it transforms the complex problem of spatial intersection line cutting into a planar layout problem, eliminating measurement errors caused by the tilt and deformation of the steel pipe piles. This results in a high-precision cutting line, ensuring the fit between the cross brace and the pile wall, reducing on-site correction work, and ensuring weld quality and structural performance. Furthermore, the invention provides a cleverly designed specialized measuring tool with clear steps for combined use, making it easy for on-site construction personnel to master. It requires no complex calculations, improving construction efficiency. Moreover, for steel pipe piles of different diameters, only the corresponding positioning ring and plastic ruler need to be replaced, demonstrating good versatility.

[0038] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for accurately determining the cutting line of the cross brace between steel pipe piles, characterized in that, Includes the following steps: Mark the design elevation of the cross bracing on the two steel pipe piles; Using the design elevation as a reference, the center of the cross brace is determined on the two steel pipe piles using a centroid measuring ruler; The installation position of the positioning device is determined with the center of the cross brace as a reference, and the positioning device is installed on the two steel pipe piles. Place the two ends of the ranging device in sequence at the preset angle positions on the positioning device, and read the horizontal distance between the two steel pipe piles at each corresponding position and the horizontal distance between the positioning device on one side and the steel pipe pile on that side. Using a top-line measuring ruler, mark out a top surface reference line parallel to the axis of the cross brace to be cut; The measured horizontal distance values ​​are transferred to the top surface baseline according to the corresponding angle using a plastic ruler, and multiple control points are marked. Connecting multiple control points into a smooth curve forms the cutting line of the cross brace; The specific process of laying out a top surface reference line parallel to the axis of the cross brace on the cross brace to be cut is as follows: Place the top line measuring ruler at both ends of the cross brace and fit it tightly against the cross brace with the limiting block. The intersection of the gaps between the vertical slits of the two top line measuring rulers and the top of the cross brace are the two vertices. Draw a line between these two vertices to form the top surface reference line of the cross brace axis. The specific process of transferring the measured horizontal distance value to the top surface baseline according to the corresponding angle and marking multiple control points is as follows: Mark the maximum horizontal distance between one of the positioning devices and the steel pipe pile on that side on the cross brace; Place the left side of the plastic ruler against the marked maximum value and wrap the plastic ruler around the cross brace so that the seam of the plastic ruler coincides with the top baseline of the cross brace. Place the measuring device at different angles marked on the plastic ruler and mark the horizontal distance between the two steel pipe piles at each corresponding position on the cross brace. Then the intersections of the two ends of the measuring device with the two ends of the cross brace are multiple control points.

2. The method for accurately determining the cutting line of the cross brace between steel pipe piles according to claim 1, characterized in that, The specific process of determining the center of the cross brace on the two steel pipe piles based on the design elevation is as follows: Place the straightedge of the centroid measuring ruler against the pile wall of the two steel pipe piles, so that the top surface of the straightedge is flush with the design elevation line. Move the two sliding rulers in the centroid measuring scale to a position that is close to the two steel pipe piles and keep them horizontal; Draw a vertical line on the sliding ruler at a point equal to the radius of the steel pipe pile. The intersection of this vertical line and the design elevation line is the center of the horizontal brace.

3. The method for accurately determining the cutting line of the cross brace between steel pipe piles according to claim 2, characterized in that, The specific process of determining the installation position of the positioning device based on the center of the cross brace and installing the positioning device on the two steel pipe piles is as follows: Place one side of the ruler close to the center of the cross brace and keep the ruler in a vertical position. Determine the hanging points of the upper and lower magnets on the steel pipe pile according to the diameter of the positioning ring in the positioning device and with the center of the cross brace as the center of symmetry. The two magnets are attached to the two designated hanging points on the steel pipe pile, one above the other. The two ends of the positioning ring are bolted to two magnets.

4. A special tool for implementing the method according to any one of claims 1-3, characterized in that, include: Centroid measuring ruler is used to determine the center of the cross brace on steel pipe piles; A positioning device is fixed on the steel pipe pile with the center of the cross brace as the center of symmetry, and is used to control the accurate position of the measuring point. The ranging device has its two ends respectively attached to the positioning devices of the two steel pipe piles, and is used to measure the straight distance between the two positioning devices in different angular directions; The top line measuring ruler is attached to both ends of the cross brace to be cut and is used to lay out the baseline of the top surface on the cross brace to be cut. A plastic ruler is wrapped around both ends of the cross brace to be cut, serving as a template for angle marking and data transfer; The top line measuring ruler includes a horizontal ruler, a vertical slit ruler, and limiting blocks. The horizontal ruler is equipped with a leveling bubble for leveling. The vertical slit ruler is vertically fixed to the middle of the horizontal ruler. The two limiting blocks are located at both ends of the horizontal ruler to contact and position the outer wall of the cross brace.

5. The special tool according to claim 4, characterized in that, The centroid measuring ruler includes a straightedge and a sliding ruler. The sliding ruler is mounted on the straightedge and can move on the straightedge. The sliding ruler is provided with scale lines.

6. The special tool according to claim 5, characterized in that, The positioning device includes a magnetic hanger and a positioning ring. The magnetic hanger is attached to the outer wall of the steel pipe pile, and the two ends of the positioning ring are respectively connected to the two magnetic hangers by bolts.

7. The special tool according to claim 6, characterized in that, The ranging device includes an outer tube and an inner tube. The inner tube is telescopically inserted into the outer tube. Both the outer tube and the inner tube have scale lines on their surfaces, and the starting directions of the two scale lines are opposite. The sum of their readings is the total length to be measured.

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