Construction coordinate transmission method and coordinate measurement transmission system suitable for deep foundation pit

Abstract

The present application relates to the technical field of foundation pit measurement, and more particularly to a construction coordinate transfer method and coordinate measurement transfer system suitable for deep foundation pit; the construction coordinate transfer method comprises the following steps: preparing step: adjusting the center of the prism to be physically collinear with the steel wire rope; obtaining the coordinates of the reflecting sheet: taking the coordinates of the center of the prism in the construction coordinate system as the coordinates of the reflecting sheet on the steel wire rope corresponding to the prism in the construction coordinate system; obtaining the coordinates of the site at the bottom of the foundation pit: combining the coordinates of the reflecting sheet in the construction coordinate system, the coordinates of the site in the construction coordinate system are obtained according to the resection method, that is, the transfer of the construction coordinate from the ground to the bottom of the foundation pit is completed; without purchasing expensive special equipment such as laser plumb instrument, the construction cost is reduced, the space occupied by the support is small, the support does not need to be removed during layer-by-layer excavation, the construction process is reduced, the coordinate transfer process is relatively simple, and the precision is high.

Description

Technical Field

[0001] This invention relates to the field of foundation pit measurement technology, and in particular to a construction coordinate transfer method and coordinate measurement transfer system suitable for deep foundation pits. Background Technology

[0002] With the rapid advancement of urbanization, large-scale infrastructure projects such as super high-rise buildings and underground rail transit are constantly emerging, and the scale and depth of deep foundation pit projects continue to break records. Precise transfer of planar coordinates is crucial to ensuring accurate construction of foundation pit support structures and seamless connection between underground structures and above-ground buildings, directly affecting project safety and construction quality.

[0003] Traditional one-well and two-well orientation methods, as classic means of transferring coordinates in deep foundation pits, have revealed many limitations in practical applications. One-well orientation requires suspending steel wire ropes in a single vertical shaft and transferring coordinates through the connecting triangle method. The operation process is cumbersome, and the shaft space is limited. After the measurement is completed, the ropes need to be removed, making it impossible to keep them in the shaft for a long time to avoid affecting subsequent construction inside the shaft. Although two-well orientation uses two vertical shafts to suspend steel wire ropes and improves accuracy by utilizing the principle of traverse surveying, it has stringent requirements on the spacing between the vertical shafts and the line-of-sight conditions, and the measurement cycle is long and the labor cost is high.

[0004] Limited by the complex geological and meteorological conditions inside deep foundation pits, the visibility is complex, and factors such as angular deviations caused by atmospheric refraction and instrument centering errors combine to make the total station free station setting method, although highly automated, have large measurement errors and cannot meet the millimeter-level accuracy requirements. In deep foundation pit environments, GNSS positioning technology suffers from a severe decrease in positioning accuracy due to satellite signal blockage and multipath effects, making it unreliable as a coordinate transfer method. Laser plumb bobs are expensive, greatly increasing construction costs.

[0005] Therefore, there is an urgent need to develop a high-precision, low-cost coordinate measurement and transfer system and a planar coordinate transfer method suitable for deep foundation pits. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a simple, low-cost, and highly accurate coordinate transfer method and coordinate measurement transfer system suitable for deep foundation pit construction.

[0007] On the one hand, this application provides a construction coordinate transfer method suitable for deep foundation pits, including the following steps:

[0008] Preparation steps: Install at least three supports on the foundation pit, install a prism on each support, suspend a steel wire rope below the prism, fix a plumb bob at the bottom of the steel wire rope, make the center of the prism collinear with the steel wire rope, and attach a reflector to the steel wire rope.

[0009] Obtaining the coordinates of the reflector: Select control points on the ground with known coordinates in the construction coordinate system. Use a total station to observe each prism at the control points. Calculate the coordinates of the center of each prism in the construction coordinate system using the traverse surveying method. Use the coordinates of the center of the prism in the construction coordinate system as the coordinates of the reflector on the corresponding steel wire rope in the construction coordinate system.

[0010] Obtain the coordinates of the station at the bottom of the foundation pit: Select a station at the bottom of the foundation pit, and use a total station to observe the reflectors on at least two of the steel wire ropes at the station. Combine the coordinates of the reflectors in the construction coordinate system, and calculate the coordinates of the station in the construction coordinate system using the resection method. This completes the transfer of construction coordinates from the ground to the bottom of the foundation pit. Leave at least one of the steel wire ropes as a verification steel wire rope, and use the reflector on the verification steel wire rope as a verification reflector. Do not observe the verification reflector.

[0011] Preliminary verification: Using the total station, observe the verification reflector to obtain the coordinates (Xp, Yp) of the verification reflector in the construction coordinate system. The coordinates of the verification reflector obtained in the step of obtaining the reflector coordinates are marked as (Xp', Yp'). The difference in the horizontal coordinate ΔX is calculated according to formula (1), and the difference in the vertical coordinate ΔY is calculated according to formula (2). The expressions of formula (1) and formula (2) are as follows:

[0012] (1)

[0013] (2);

[0014] Based on the difference in the horizontal coordinate ΔX and the difference in the vertical coordinate ΔY, determine whether the coordinate transfer accuracy meets the requirements.

[0015] In some embodiments of this application, when the difference in the horizontal coordinate ΔX ≤ the set horizontal coordinate deviation and the difference in the vertical coordinate ΔY ≤ the set vertical coordinate difference, it is determined that the coordinate transfer accuracy meets the requirements.

[0016] When the set horizontal coordinate deviation value < horizontal coordinate difference ΔX ≤ maximum horizontal coordinate deviation value, or the set vertical coordinate difference < vertical coordinate difference ΔY ≤ maximum vertical coordinate deviation value, it is determined that the coordinate transmission accuracy does not meet the requirements, and the verticality of each wire rope and the accuracy of the conductor measurement in the step of obtaining the reflector coordinates are checked to see if they meet the requirements.

[0017] In some embodiments of this application, the deep foundation pit is constructed using a layer-by-layer excavation method. As the foundation pit is excavated layer by layer, the step of obtaining the coordinates of the bottom of the foundation pit is performed once for each layer excavated, so as to complete the coordinate transfer of construction coordinates from the ground to the bottom of each layer of the foundation pit.

[0018] In some embodiments of this application, after the coordinate transfer of the i-th layer of the foundation pit is completed, multiple points are selected on the sidewall of the foundation pit and marked as check points. The coordinates of the check points are measured using a total station at the bottom of the i-th layer of the foundation pit as (X... ij Y ij ), where i represents the i-th layer of foundation pit, and j represents the label of the check point;

[0019] After the coordinate transfer of the (i+1)th layer of the foundation pit is completed, the coordinates of the check point are measured using a total station at the bottom of the (i+1)th layer of the foundation pit as (X... （i+1）j Y （i+1）j );

[0020] The coordinate transfer accuracy of the (i+1)th layer of the foundation pit is checked a second time: the difference in the horizontal coordinate ΔX' is calculated according to formula (3), and the difference in the vertical coordinate ΔY' is calculated according to formula (4). The expressions of formula (3) and formula (4) are as follows:

[0021] (3)

[0022] (4);

[0023] Compare the difference in the horizontal coordinate ΔX' and the difference in the vertical coordinate ΔY' to determine whether the coordinate transfer accuracy meets the requirements.

[0024] In some embodiments of this application, during the preparation step, the plumb bob is placed in a container filled with damping fluid to prevent the plumb bob from swinging under external interference, thereby keeping the wire rope in a stable vertical state and improving measurement accuracy.

[0025] On the other hand, this application also provides a coordinate measurement transfer system, including:

[0026] A support frame is installed on the side wall of the foundation pit, and a horizontal mounting seat is installed at the end of the support frame. The support frame is used to adjust the levelness of the horizontal mounting seat.

[0027] A prism having a base, the base being mounted on the horizontal mounting base;

[0028] A steel wire rope is fixed at the center of the base, and a plumb bob is fixed at the bottom end of the steel wire rope to keep the steel wire rope in a vertical position.

[0029] A reflector, which is fixed to the steel wire rope;

[0030] A total station, set at a control point on the ground or at a station at the bottom of the pit, is used to observe the prism or the reflector.

[0031] In some embodiments of this application, the bracket includes a horizontal fixing frame and a supporting diagonal bar;

[0032] The inner end of the horizontal fixing frame is installed on the side wall of the pit, and the horizontal mounting seat is installed on the outer end of the horizontal fixing frame. The horizontal fixing frame rotates relative to the side wall of the pit to adjust the levelness of the horizontal mounting seat.

[0033] One end of the support diagonal rod is installed on the horizontal fixed frame, and the other end is installed on the side wall of the foundation pit. The support diagonal rod is a telescopic structure so that the horizontal fixed frame can be rotated relative to the side wall of the foundation pit through the extension and retraction of the support diagonal rod.

[0034] In some embodiments of this application, the horizontal fixing frame includes two opposing adjusting brackets with a gap between them, and a mounting hole is provided at the center of the horizontal mounting base, the mounting hole being located above the gap;

[0035] Each of the adjustment brackets is equipped with a support diagonal rod below it. By adjusting the length of two support diagonal rods, the corresponding adjustment bracket is rotated relative to the pit sidewall, so that the horizontal mounting base is in a horizontal state.

[0036] In some embodiments of this application, the supporting diagonal rod includes screws at both ends and a hollow connecting pipe connecting the two screws. One end of the two screws is fixed to the pit sidewall and the horizontal fixing frame, respectively, and the other end is threaded to the connecting pipe.

[0037] Based on the above technical solution, the construction coordinate transfer method applicable to deep foundation pits of the present invention adjusts the center of the prism to be physically collinear with the steel wire rope, and uses the construction coordinates of the center of the prism as the construction coordinates of the reflector. The bottom of the foundation pit station uses a total station to observe the reflector on the steel wire rope. The reflector solves the problem of signal blockage and realizes the transfer of construction coordinates from the ground to the bottom of the foundation pit.

[0038] By setting up at least three steel wire ropes and observing the reflectors on two of them, the construction coordinate system coordinates of the site can be determined. Observing the reflectors on the remaining steel wire ropes can verify the coordinates and improve the accuracy of coordinate transmission.

[0039] When the foundation pit is excavated layer by layer, the coordinate transfer of the bottom of the current foundation pit is checked again by selecting the check point of the previous layer of foundation pit, which further improves the accuracy of coordinate transfer.

[0040] The coordinate measurement and transfer system of the present invention utilizes measuring instruments and support structures such as prisms, total stations, steel wire ropes, and reflectors, eliminating the need to purchase expensive specialized equipment such as laser plumb bobs, thus reducing construction costs. Furthermore, the support occupies little space, and there is no need to dismantle the support during layer-by-layer excavation, reducing construction procedures. The coordinate transfer process is relatively simple and has high accuracy.

[0041] Adjusting the length of the two support diagonal rods corresponds to adjusting the relative height of the two adjustment brackets, so that the horizontal mounting base is in a horizontal state, and the prism on the horizontal mounting base is in a horizontal state. The center of the prism is collinear with the steel wire rope. In practical applications, this method has good feasibility and effectiveness, and provides a low-cost, high-reliability solution for deep foundation pit engineering surveying, which has high promotion and application value. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0043] Figure 1 This is a flowchart of the construction coordinate transfer method applicable to deep foundation pits according to the present invention;

[0044] Figure 2 This is a schematic diagram showing the positional relationship of the bracket, prism, wire rope, and plumb bob according to an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of a coordinate transfer system according to an embodiment of the present invention;

[0046] Figure 4 This is a three-dimensional structural diagram of a bracket according to an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the structure of a prism according to an embodiment of the present invention;

[0048] Figure 6 This is a side view of a horizontal fixing frame according to an embodiment of the present invention;

[0049] Figure 7 This is a top view of a horizontal fixing frame according to an embodiment of the present invention;

[0050] Figure 8 This is a schematic diagram of the structure of a support diagonal rod according to an embodiment of the present invention;

[0051] Figure 9 This is a schematic diagram of the location of the foundation pit in Embodiment 1 of the present invention;

[0052] Figure 10 This is a schematic diagram of the conductor measurement principle in Embodiment 1 of the present invention.

[0053] In the diagram, 10 is the foundation pit; 11 is the side wall.

[0054] 20. Bracket;

[0055] 21. Horizontal fixing frame; 211. Adjusting bracket; 212. Adjusting gap;

[0056] 22. Supporting diagonal brace; 221. Screw rod; 222. Connecting pipe;

[0057] 23. Mounting base; 231. Base plate; 232. Mounting plate;

[0058] 30. Prism; 31. Base; 32. Connecting screw;

[0059] 40. Steel wire rope; 401. Verified steel wire rope; 41. Plumb bob; 42. Reflector; 421. Verified reflector; 43. Container;

[0060] 50. Total station; 60. Horizontal mounting base; 61. Mounting hole. Detailed Implementation

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0062] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0063] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0064] like Figures 1-3 As shown in the illustration, an illustrative embodiment of the present invention provides a construction coordinate transfer method suitable for deep foundation pits, comprising the following steps:

[0065] S1 Preparation Steps: Install at least two supports 20 on the foundation pit 10, and install a prism 30 on each support 20. Suspend a steel wire rope 40 below the prism 30, and fix a plumb bob 41 to the bottom of the steel wire rope 40 so that the center of the prism 30 is collinear with the steel wire rope 40. Attach a reflector 42 to the steel wire rope 40. Figure 2 As shown;

[0066] S2 Obtain the coordinates of the reflector: Select control points on the ground with known coordinates in the construction coordinate system. Use a total station to observe each prism 30 at the control points. Calculate the coordinates of the center of each prism 30 in the construction coordinate system according to the traverse surveying method. Use the coordinates of the center of the prism 30 in the construction coordinate system as the coordinates of the reflector 42 on the corresponding steel wire rope 40 in the construction coordinate system.

[0067] S3 Obtain the coordinates of the bottom of the foundation pit: Select a station at the bottom of the foundation pit 10, and use a total station to observe the reflectors 42 on at least two steel wire ropes 40 at the station. Combine the coordinates of the reflectors 42 in the construction coordinate system, and calculate the coordinates of the station in the construction coordinate system according to the resection method, thus completing the transfer of construction coordinates from the ground to the bottom of the foundation pit.

[0068] It should be noted that in step S2, the total station 50 at the control point must be in line with the prism 30 to obtain the coordinates of the station at the bottom of the foundation pit. When selecting the station at the bottom of the foundation pit, the total station 50 at the station must be in line with the reflector 42 on the steel wire rope 40 to ensure that the total station can receive the signals reflected by the prism 30 and the reflector 42, so that the measurement can be carried out smoothly.

[0069] The above-mentioned construction coordinate transfer method applicable to deep foundation pits utilizes existing surveying instruments and support structures such as prisms, total stations, wire ropes, and reflectors, eliminating the need to purchase expensive specialized equipment and reducing costs. The center of prism 30 is collinear with the wire rope 40, achieving physical coaxiality between the center of prism 30 and the reflector 42 on the wire rope 40. The coordinates of the center of prism 30 are used as the coordinates of the reflector on the coaxial wire rope 40. By observing the reflectors on the two wire ropes 40 with known coordinates using a total station at the bottom of the foundation pit 10, the measurement calculation is performed using traverse surveying and resection methods, making the measurement process relatively simple.

[0070] In some embodiments, to verify the accuracy of coordinate transfer, at least three supports 20 are installed in the foundation pit 10; in step S3, when observing the reflector 42, the station uses a total station to observe the reflector 42 on at least two steel wire ropes 40, leaving at least one steel wire rope 40 as a verification steel wire rope 401, and the reflector on the verification steel wire rope 401 as a verification reflector 421, such as Figure 3 As shown, in step S3, the total station at the station does not observe the verification reflector 421.

[0071] In some embodiments, the coordinate transfer method further includes preliminary verification: using a total station to observe and verify the reflector 421, obtaining the coordinates (Xp, Yp) of the reflector 421 in the construction coordinate system, and marking the coordinates of the reflector 421 obtained in the step of obtaining the reflector coordinates as (Xp', Yp'), calculating the difference in the horizontal coordinate ΔX according to formula (1), and calculating the difference in the vertical coordinate ΔY according to formula (2). The expressions of formula (1) and formula (2) are as follows:

[0072] (1)

[0073] (2);

[0074] By comparing the difference in the horizontal coordinate ΔX and the difference in the vertical coordinate ΔY, it is determined whether the coordinate transfer accuracy meets the requirements. The verification process is relatively simple. After obtaining the coordinates of the station at the bottom of the foundation pit, the total station can observe the verification reflector 421 to carry out the preliminary verification step.

[0075] This embodiment, by installing at least three supports 20 in the foundation pit 10, can both complete the coordinate transfer and verify the accuracy of the coordinate transfer, ensuring the accuracy of the coordinate transfer and improving construction efficiency.

[0076] In some embodiments, when the difference in the horizontal coordinate ΔX is less than or equal to the set horizontal coordinate deviation and the difference in the vertical coordinate ΔY is less than or equal to the set vertical coordinate difference, the coordinate transfer accuracy is determined to meet the requirements.

[0077] When the set horizontal coordinate deviation value < horizontal coordinate difference ΔX ≤ maximum horizontal coordinate deviation value, or the set vertical coordinate difference value < vertical coordinate difference ΔY ≤ maximum vertical coordinate deviation value, it is determined that the coordinate transfer accuracy does not meet the requirements. Check whether the verticality of each wire rope 40 and the accuracy of the conductor measurement in the step of obtaining the reflector coordinates meet the requirements. After finding the cause and correcting it, repeat steps S2 and S3 to obtain the corrected coordinates of the station in the construction coordinate system. Perform the preliminary verification step again until the coordinate transfer accuracy meets the requirements, further ensuring the accuracy of the transfer.

[0078] In some embodiments, the horizontal coordinate deviation and the vertical coordinate deviation are both set to ±5mm, and the maximum horizontal coordinate deviation and the maximum vertical coordinate deviation are both ±8mm. When the horizontal coordinate difference ΔX≤±5mm and the vertical coordinate difference ΔY≤±5mm, the coordinate transfer accuracy is determined to meet the requirements.

[0079] When ±5mm < x-coordinate difference ΔX ≤ ±8mm, or ±5mm < y-coordinate difference ΔY ≤ ±8mm, the coordinate transfer accuracy is deemed not to meet the requirements.

[0080] In some embodiments, when the foundation pit 10 is deep, a layer-by-layer excavation method is adopted. As the foundation pit is excavated layer by layer, the coordinates of the bottom of the foundation pit are obtained after each layer is excavated, thus completing the coordinate transfer from the ground to the bottom of each layer. When excavating the foundation pit 10 to the next layer, the support 20 occupies little space and does not need to be dismantled. This avoids the systematic deviation caused by reinstalling the support 20, which would require reinstalling the prism 30, wire rope 40, and reflector 42. This reduces sources of error, further improving the accuracy of coordinate transfer and increasing construction efficiency. During coordinate transfer at each layer of the foundation pit, the construction coordinates of the prism's center are used as the construction coordinates of the reflector, avoiding systematic errors caused by changes in the prism's center coordinates after the support is dismantled and reinstalled.

[0081] It should be noted that in step S1, the length of the steel wire rope 40 is selected to be greater than the overall height of the foundation pit 10. In the initial preparation steps, part of the steel wire rope 40 can be suspended below the prism 30 so that when the coordinate transfer of the first layer of foundation pit is carried out, the total station 50 at the bottom station of the foundation pit can observe the reflector 42 on the steel wire rope 40. When excavating to the second layer of foundation pit, if the total station 50 at the second layer of foundation pit can still observe the reflector 42 on the steel wire rope 40, the length of the steel wire rope 40 remains unchanged. When excavating to the nth layer of foundation pit, the total station 50 at the bottom station of this layer of foundation pit cannot observe the reflector 42 on the steel wire rope 40. The steel wire rope 40 can be lowered to make the steel wire rope below the prism 30 longer. A reflector 42 that can be seen through the total station 50 at the nth layer of foundation pit is attached to the steel wire rope 40 to meet the observation needs of the total station 50 at the current foundation pit station.

[0082] In some embodiments, after each layer of the foundation pit 10 is excavated, the coordinate transfer accuracy of the current layer is preliminarily checked to ensure that the coordinate transfer accuracy of each layer of the foundation pit meets the requirements.

[0083] In some embodiments, after the coordinate transfer of the i-th layer of the foundation pit is completed, multiple points are selected on the sidewall of the foundation pit 10 and marked as check points. The coordinates of the check points are measured using a total station 50 at the bottom of the i-th layer of the foundation pit (X). ij Y ij ), where i represents the i-th layer of foundation pit, and j represents the label of the check point;

[0084] After the coordinate transfer of the (i+1)th layer of the foundation pit is completed, the coordinates of the verification points are measured using a total station 50 at the bottom of the (i+1)th layer of the foundation pit, and are denoted as (X). （i+1）j Y （i+1）j );

[0085] The coordinate transfer accuracy of the (i+1)th layer of the foundation pit is checked a second time: the difference in the horizontal coordinate ΔX' is calculated according to formula (3), and the difference in the vertical coordinate ΔY' is calculated according to formula (4). The expressions of formula (3) and formula (4) are as follows:

[0086] (3)

[0087] (4);

[0088] By comparing the difference in the horizontal coordinate ΔX' and the difference in the vertical coordinate ΔY', it is determined whether the coordinate transfer accuracy meets the requirements, thus further ensuring the accuracy of coordinate transfer. By selecting the check point of the previous layer of foundation pit, the coordinate transfer at the bottom of the current foundation pit is checked again, which further improves the accuracy of coordinate transfer.

[0089] In this invention, when the difference between the horizontal coordinate ΔX' and the difference between the vertical coordinate ΔY' are both less than or equal to ±5mm, the coordinate transfer is considered to meet the accuracy requirements.

[0090] In some embodiments, in step S1, the plumb bob 41 is placed in a container 43 containing damping fluid to prevent the plumb bob 41 from swinging under external interference, so that the wire rope 40 remains in a stable vertical state and the measurement accuracy is improved. The mass of the plumb bob 41 should be selected according to the actual situation to ensure that the wire rope 40 is in a vertically taut state. The container 43 is a barrel-shaped container. The damping fluid is generally a liquid with moderate viscosity and good stability, such as silicone oil.

[0091] Based on the above-described coordinate transfer method applicable to deep foundation pit construction, this invention also provides a coordinate measurement and transfer system, such as... Figures 2-3 As shown, it includes a bracket 20, a prism 30, a steel wire rope 40, a plumb bob 41, and a reflector 42; it eliminates the need to purchase expensive laser plumb bobs and other specialized equipment, thus reducing costs.

[0092] The bracket 20 is set on the side wall of the foundation pit 10. A horizontal mounting seat 60 is installed at the end of the bracket 20. The bracket 20 is used to adjust the levelness of the horizontal mounting seat 60. After the horizontal mounting seat 60 is adjusted to a horizontal state, there is no need to reinstall and adjust the horizontal mounting seat 60 during subsequent construction and coordinate transfer during layer-by-layer excavation, which reduces construction procedures and improves the accuracy of coordinate transfer.

[0093] Prism 30 is mounted on horizontal mounting base 60, wherein prism 30 has base 31, such as Figure 5 As shown, the base 31 is mounted on the horizontal mounting base 60.

[0094] The wire rope 40 is fixed at the center of the base 31, and a plumb bob 41 is fixed at the bottom of the wire rope 40, so that the wire rope 40 is in a vertical state.

[0095] The reflector 42 is attached to the appropriate position on the wire rope 40. The reflector 42 should be attached firmly and flat, and the reflective surface should face the measurement direction at the bottom of the pit to ensure the strength of the reflected signal.

[0096] The total station 50 is set at a control point on the ground or at a station at the bottom of the foundation pit, and can observe the prism 30 and the reflector 42 respectively.

[0097] In some embodiments, the bracket 20 includes a horizontal fixing frame 21 and a supporting diagonal rod 22; such as Figure 4 As shown, the inner end of the horizontal fixing frame 21 is fixed to the side wall 11 of the pit 10, and the outer end of the horizontal fixing frame 21 is equipped with a horizontal mounting seat 60. The outer end of the horizontal fixing frame 21 rotates relative to the side wall 11 to adjust the levelness of the horizontal mounting seat 60 so that the horizontal mounting seat 60 is in a horizontal state, thereby making the prism 30 installed on the horizontal mounting seat 60 in a horizontal state.

[0098] The outer end of the support diagonal rod 22 is installed on the horizontal fixed frame 21, and the inner end is installed on the side wall 11 of the foundation pit. The support diagonal rod 22 is a telescopic structure, so that the horizontal fixed frame 21 can be rotated in the vertical direction relative to the side wall 11 of the foundation pit by the extension and retraction of the support diagonal rod 22. During the adjustment process, a level is used on the horizontal mounting seat 60 to calibrate the levelness. The adjustment process is convenient and quick, ensuring that the horizontal mounting seat 60 is in a horizontal state.

[0099] In some embodiments, the inner end of the support rod 22 is fixed to the side wall 11 below the horizontal fixing frame 21, and the horizontal fixing frame 21, the support rod 22, and part of the side wall 11 form a triangular structure. When the support rod 22 extends, the outer end of the horizontal fixing frame 21 rotates upward relative to the side wall 11, and the outer end of the corresponding horizontal mounting seat 60 moves upward relative to its inner end. When the support rod 22 retracts, the outer end of the horizontal fixing frame 21 rotates downward relative to the side wall 11, and the outer end of the corresponding horizontal mounting seat 60 moves downward relative to its inner end. The relative height of the inner and outer ends of the horizontal mounting seat 60 can be adjusted. The inner and outer ends of the horizontal mounting seat 60 are respectively equipped with a level. When the bubble of the level is in the middle position, the inner and outer ends of the horizontal mounting seat 60 are in a horizontal state.

[0100] In some embodiments, the horizontal fixing frame 21 includes two horizontally opposite adjusting brackets 211, with an adjusting gap 212 between the two adjusting brackets 211, such as... Figure 6 As shown; Figure 4 As shown, a mounting hole 61 is provided at the center of the horizontal mounting base 60, and the mounting hole 61 is located above the adjustment gap 212.

[0101] Each adjusting bracket 211 is equipped with a support rod 22 below it. By adjusting the length of the two support rods 22, the corresponding adjusting bracket 211 is rotated relative to the side wall 11, thereby adjusting the relative height of the left and right sides of the horizontal mounting base 60. A level is also set on the left and right sides of the horizontal mounting base 60. When the bubble of the level is in the middle position, the left and right sides of the horizontal mounting base 60 are in a horizontal state.

[0102] In actual construction, by adjusting the length of the two supporting diagonal rods 22, the relative height of the front and rear ends and the left and right sides of the horizontal mounting base 60 can be adjusted simultaneously. When the bubbles of the level instruments at the front and rear ends and the left and right sides of the horizontal mounting base 60 are all in the middle position, the horizontal mounting base 60 is in a horizontal state. The adjustment process is simple.

[0103] In some embodiments, before the prism 30 is installed on the horizontal mounting base 60, the horizontal mounting base 60 must first be adjusted to a horizontal state. A vertically downward connecting screw 32 is fixed at the center of the base 31 of the prism 30, and the central axis of the connecting screw 32 is collinear with the center of the prism 30. The connecting screw 32 passes through the mounting hole 61 on the horizontal mounting base 60 and the adjustment gap 212 of the horizontal fixing bracket 21, and embeds the base 31 into the horizontal mounting base 60. When disassembling the prism 30, the base can be pulled upwards for easy disassembly and assembly.

[0104] To ensure that the prism 30 is horizontal, the base 31 also needs to be adjusted to a horizontal position; for example... Figure 5 As shown, the base 31 has a triangular structure. The base 31 is leveled by the leveling bolt (not shown in the figure) at the top corner. The level of the base 31 is also checked by a level. After the base 31 is adjusted to a horizontal state, the center of the prism 30 is collinear with the wire rope 40. The construction coordinates of the center of the prism 30 can be used as the construction coordinates of the reflector 42 on the wire rope 40.

[0105] In some embodiments, such as Figure 8 As shown, the support rod 22 includes screws 221 at both ends and a hollow connecting tube 222 connecting the two screws 221. The connecting tube 222 has internal threads. The lower end of the lower screw 221 is fixed to the side wall 11 of the pit, and the upper end of the upper screw 221 is bolted to the adjusting bracket 211. When the connecting tube 222 is manually rotated, the screws 221 at both ends are screwed out or retracted relative to the connecting tube 222, which changes the overall length of the support rod 22 and drives the adjusting bracket 211 to rotate relative to the side wall 11.

[0106] In some embodiments, to ensure that the bracket 20 does not shake during the measurement process and to guarantee the accuracy of the measurement, the bracket 20 should be firmly and stably installed. Therefore, the inner end of the horizontal fixing frame 21 and the lower end of the supporting diagonal rod are fixed to the side wall 11 by two mounting bases 23 set above and below. The mounting bases 23 are fixed to the side wall 11 by embedded parts or expansion bolts.

[0107] Specifically, the mounting base 23 includes a base plate 231 vertically attached to the side wall 11 and two mounting plates 232 vertically arranged and perpendicular to the base plate. The base plate 231 is fixed to the side wall 11 by bolts. The two mounting plates 232 of the upper mounting base 23 fix the inner end of the horizontal fixing frame 21, and the two mounting plates 232 of the lower mounting base 23 fix the lower end screw 221. The mounting base 23 enables the horizontal fixing frame 21 and the supporting diagonal rod 22 to be firmly installed on the side wall 11, reducing measurement errors and ensuring the accuracy of coordinate transmission.

[0108] In some embodiments, such as Figure 7 As shown, the adjusting bracket 211 is a ┌-shaped plate. The two adjusting brackets 211 are placed in mirror symmetry. An adjusting gap 212 is formed between the horizontal plates of the two adjusting brackets 211. The vertical plate of the adjusting bracket 211 is hinged to the mounting plate 232 located above by bolts, so that the two adjusting brackets 211 can rotate around the mounting plate 232 respectively.

[0109] The lower end of the screw 221 located below is bolted to the mounting plate 232 located below, and the upper end of the screw 221 located above is bolted to the adjusting bracket 211. By manually rotating the connecting pipe 222, the screws 221 at both ends are screwed out or retracted relative to the connecting pipe 222, which changes the overall length of the supporting diagonal rod 22, causing the adjusting bracket 211 to rotate relative to the mounting plate 232. The adjustment can be completed by only one person, which is simple and efficient.

[0110] Example 1

[0111] Taking the foundation pit 10 at the north bank of a certain inland river immersed tunnel project as an example, such as... Figure 9 The following describes the construction coordinate transfer method for deep foundation pits provided by the present invention:

[0112] In this embodiment, the bottom elevation of the excavation pit 10 is -15.326 to -18.587 m, and the excavation depth is 18.826 to 22.087 m. The pit 10 employs a reinforced concrete support + steel support scheme, with five layers of support. The first layer of support uses 1000×1000 mm reinforced concrete horizontal bracing; the second and third layers use φ800 steel supports; two lattice columns are evenly distributed every eight meters along the transverse direction for connection with the steel supports; the fourth layer uses 1400×1200 mm reinforced concrete horizontal bracing; and the fifth layer uses 1000×1000 mm reinforced concrete horizontal bracing.

[0113] (1) Preparation steps: such as Figure 3 As shown, three supports 20 are installed on the side wall 11 of the foundation pit 10. The three supports 20 are located at the three apex corners of the foundation pit. The verticality of the supports 20 is calibrated using a plumb bob or total station to ensure that they are in a vertical state.

[0114] Place the horizontal mounting base 60 on the outer end of the bracket 20, and adjust the length of the support diagonal rod 22 of each bracket 20 in sequence so that the adjusting bracket 211 rotates around the side wall 11. Use a level to adjust the horizontal mounting base 60 to a horizontal state.

[0115] When the horizontal mounting base 60 is in a horizontal position, install the prism 30 on the horizontal mounting base 60. Pass the connecting screw 32 under the base 31 through the mounting hole 61 on the horizontal mounting base 60 and the adjustment gap 212 of the horizontal fixing bracket 21. The base 31 is then embedded in the horizontal mounting base 60, completing the installation of the prism 30. Check the base 31 again with a level and adjust the leveling bolts to ensure that the base 31 is in a horizontal position. Ensure that the prism 30 is securely installed and that the mirror surface is clean. This ensures accurate reception and transmission of measurement signals from the total station 50 located at the ground control point.

[0116] The wire rope 40 is fixed to the connecting screw 32, and a plumb bob 41 is fixed to the bottom end of the wire rope 40. In this embodiment, the plumb bob 41 weighs 15kg to ensure that the wire rope 40 is in a vertically taut state. A container 43 is placed at the bottom of the pit 10 corresponding to the wire rope 40, and damping fluid is placed in the container 43. The plumb bob 41 is immersed in the damping fluid. The damping fluid can effectively suppress the error caused by the swing of the wire rope 40, so that the center of the prism 30 is coaxial with the wire rope 40, and the coaxiality deviation is ≤0.5 mm.

[0117] Since the foundation pit 10 in this embodiment has multiple steel supports, in order to avoid signal obstruction, high-precision reflective sheets 42 are pasted on the steel wire rope 40 every 2 meters and fixed with special waterproof adhesive to ensure that the pasting is firm and flat; the angle between the reflective surface of the reflective sheet 42 and the line of sight of the total station 50 at the bottom of the foundation pit is ≤5° to ensure the strength of the reflected signal.

[0118] (2) Obtaining the coordinates of the reflector: In accordance with the specifications of the traverse surveying method, four urban second-order control points O1, O2, O3, and O4 with known coordinates were selected around the foundation pit 10. Among them, O1 and O4 are on the south bank, and O2 and O3 are on the north bank, next to the foundation pit. The control points on the south and north banks were connected to ensure the measurement accuracy of the south and north banks during on-site construction. The three prisms 30 inside the foundation pit 10 were marked as A1, A2, and A1. A closed traverse surveying method was adopted, such as... Figure 10 As shown;

[0119] First, install a total station 50 at control point O1. The total station 50 is a high-precision total station (angle measurement accuracy ±1″, distance measurement accuracy ±(1mm + 1ppm×D)). Perform instrument centering and leveling operations to ensure that the total station 50 is in an accurate measurement state. Install prisms at control points O2 and O4. At this time, the total station 50 observes the horizontal angle, vertical angle and slope distance of the prisms at control points O2 and O4.

[0120] Then, the total station 50 is moved to control point O2, the prism of O2 is moved to O3, and the prism of O4 is moved to O1. At this time, the total station 50 observes the horizontal angle, vertical angle and slope distance of the prisms on O1, A1, A2, A3 and O3 in sequence.

[0121] Then move the total station 50 to control point O3, move the prism of O3 to O4, and move the prism of O1 to O2. At this time, the total station 50 observes the horizontal angle, vertical angle and slope distance of the prisms on O2, A1, A2, A3 and O4 in sequence.

[0122] Finally, the total station 50 is moved to control point O4, the prism at O4 is moved to O1, and the prism at O2 is moved to O3. At this time, the total station 50 observes the horizontal angle, vertical angle and slope distance of the prisms at O1 and O3 in turn.

[0123] To improve measurement accuracy, this embodiment conducted four rounds of observations to ensure the accuracy and reliability of the observation data. The horizontal angle, vertical angle, and slant distance data of each observation were recorded. Professional measurement adjustment software, such as Southern Adjustment Easy or COSA Adjustment Software, was used to perform adjustment calculations on the observation data. After adjustment, the relative closure error of the total traverse length was 1 / 80000. The plane coordinates of the prisms 30 on the three supports 20 in the construction coordinate system were calculated, which are the coordinates of the corresponding reflectors 42 below the three prisms 30 in the construction coordinate system.

[0124] (3) Obtain the coordinates of the station at the bottom of the foundation pit: Select a station at a suitable position at the bottom of the foundation pit 10, remove the total station 50 installed on the ground control point O4, and install it on the station at the bottom of the foundation pit. Use the same total station for observation to reduce the change in measurement accuracy caused by instrument error. The total station 50 observes the horizontal angle, vertical angle and slant distance of the reflector 42 on the steel wire rope 40 corresponding to A1 and A2. Combine the coordinates of the reflector 42 in the construction coordinate system, and calculate the coordinates of the station in the construction coordinate system according to the resection method, that is, complete the transfer of construction coordinates from the ground to the bottom of the foundation pit.

[0125] Using the steel wire rope 40 corresponding to prism A3 as the verification steel wire rope 401, and the reflector on the verification steel wire rope 401 as the verification reflector 421, during the process of obtaining the coordinates of the bottom of the foundation pit, the total station 50 at the site does not observe the verification reflector 421.

[0126] After obtaining the construction coordinates of the site, a preliminary verification is performed: the total station 50 at the site observes the verification reflector 421 again to obtain the coordinates (Xp, Yp) of the verification reflector 421 in the construction coordinate system. The coordinates of the verification reflector 421 obtained during the traverse survey are marked as (Xp', Yp'). The difference in the horizontal coordinate ΔX is calculated according to formula (1), and the difference in the vertical coordinate ΔY is calculated according to formula (2). The expressions of formula (1) and formula (2) are as follows:

[0127] (1)

[0128] (2);

[0129] If ΔX and ΔY are both ≤ ±5mm, it is considered that the coordinate transfer accuracy meets the requirements.

[0130] In this embodiment, the foundation pit is quite deep, requiring excavation layer by layer. After the coordinate transfer of the bottom of the first layer of the foundation pit is completed, 10 known coordinate points are marked on the side wall of the foundation pit of this layer as check points for accuracy verification. The total station 50 is then removed, but the support 20, prism 30, wire rope 40, and plumb bob 41 do not need to be removed. The excavation of the first layer continues. After the excavation of the second layer is completed, a station is selected at the bottom of the foundation pit of this layer, and the total station 50 is installed. The total station 50 observes the reflectors 42 corresponding to A1 and A2 again to obtain the coordinates of the bottom station of the second layer of the foundation pit, completing the transfer of coordinates from the ground to the second layer of the foundation pit. It should be noted that if the total station 50 at the bottom station of the second layer of the foundation pit cannot observe the reflector 42, the wire rope 40 needs to be lowered, and a reflector that can be seen through the total station 50 needs to be attached to the wire rope 40 to complete the observation of the reflector 42.

[0131] The total station 50 observes the verification reflector 421 corresponding to prism A3 to perform a preliminary verification of the coordinate transfer accuracy of the second-layer foundation pit. After the preliminary verification meets the requirements, a second verification is performed: the coordinates obtained by the total station 50 at the second-layer station measuring the 10 verification points marked in the first layer are compared with the coordinate values ​​of the verification points obtained after the coordinate transfer of the first-layer foundation pit is completed, as shown in Table 1.

[0132] Table 1. Measured coordinates of the verification points in the first and second layers of the foundation pit.

[0133]

[0134] As can be seen from the table, the coordinate differences ΔX' and ΔY' of the 10 verification points are all controlled within ±3.1mm, which meets the accuracy requirements of ≤±5mm.

[0135] The excavation of the foundation pit continues, and the above steps of obtaining the coordinates of the bottom of the foundation pit, the preliminary verification step, and the secondary verification step are repeated until the excavation reaches the design depth. The construction coordinates are then transferred to the bottom of the foundation pit in sequence.

[0136] Based on the above embodiments, the construction coordinate transfer method of the present invention applicable to deep foundation pits, by adjusting the center of the prism to be physically collinear with the steel wire rope, uses the construction coordinates of the center of the prism as the construction coordinates of the reflector. The bottom of the foundation pit station uses a total station to observe the reflector on the steel wire rope. The reflector solves the problem of signal blockage and realizes the transfer of construction coordinates from the ground to the bottom of the foundation pit.

[0137] By setting up at least three steel wire ropes and observing the reflectors on two of them, the construction coordinate system coordinates of the site can be determined. Observing the reflectors on the remaining steel wire ropes can verify the coordinates and improve the accuracy of coordinate transmission.

[0138] When the foundation pit is excavated layer by layer, the coordinate transfer of the bottom of the current foundation pit is checked again by selecting the check point of the previous layer of foundation pit, which further improves the accuracy of coordinate transfer.

[0139] The coordinate measurement and transfer system of the present invention utilizes measuring instruments and support structures such as prisms, total stations, steel wire ropes, and reflectors, eliminating the need to purchase expensive specialized equipment such as laser plumb bobs, thus reducing construction costs. Furthermore, the support occupies little space, and there is no need to dismantle the support during layer-by-layer excavation, reducing construction procedures. The coordinate transfer process is relatively simple and has high accuracy.

[0140] Adjusting the length of the two support diagonal rods corresponds to adjusting the relative height of the two adjustment brackets, so that the horizontal mounting base is in a horizontal state, and the prism on the horizontal mounting base is in a horizontal state. The center of the prism is collinear with the steel wire rope. In practical applications, this method has good feasibility and effectiveness, and provides a low-cost, high-reliability solution for deep foundation pit engineering surveying, which has high promotion and application value.

[0141] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0142] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A construction coordinate transfer method suitable for deep foundation pits, characterized in that, Includes the following steps: Preparation steps: Install at least three supports on the foundation pit, install a prism on each support, suspend a steel wire rope below the prism, fix a plumb bob at the bottom of the steel wire rope, make the center of the prism collinear with the steel wire rope, and attach a reflector to the steel wire rope. Obtaining the coordinates of the reflector: Select control points on the ground with known coordinates in the construction coordinate system. Use a total station to observe each prism at the control points. Calculate the coordinates of the center of each prism in the construction coordinate system using the traverse surveying method. Use the coordinates of the center of the prism in the construction coordinate system as the coordinates of the reflector on the corresponding steel wire rope in the construction coordinate system. Obtain the coordinates of the station at the bottom of the foundation pit: Select a station at the bottom of the foundation pit, and use a total station to observe the reflectors on at least two of the steel wire ropes at the station. Combine the coordinates of the reflectors in the construction coordinate system, and calculate the coordinates of the station in the construction coordinate system using the resection method. This completes the transfer of construction coordinates from the ground to the bottom of the foundation pit. Leave at least one of the steel wire ropes as a verification steel wire rope, and use the reflector on the verification steel wire rope as a verification reflector. Do not observe the verification reflector. Preliminary verification: Using the total station, observe the verification reflector to obtain the coordinates (Xp, Yp) of the verification reflector in the construction coordinate system. The coordinates of the verification reflector obtained in the step of obtaining the reflector coordinates are marked as (Xp', Yp'). The difference in the horizontal coordinate ΔX is calculated according to formula (1), and the difference in the vertical coordinate ΔY is calculated according to formula (2). The expressions of formula (1) and formula (2) are as follows: （1） （2）； Based on the difference in the horizontal coordinate ΔX and the difference in the vertical coordinate ΔY, determine whether the coordinate transfer accuracy meets the requirements.

2. The construction coordinate transfer method for deep foundation pits according to claim 1, characterized in that, When the difference in the horizontal coordinate ΔX is less than or equal to the set horizontal coordinate deviation, and the difference in the vertical coordinate ΔY is less than or equal to the set vertical coordinate difference, the coordinate transmission accuracy is determined to meet the requirements. When the set horizontal coordinate deviation value < horizontal coordinate difference ΔX ≤ maximum horizontal coordinate deviation value, or the set vertical coordinate difference < vertical coordinate difference ΔY ≤ maximum vertical coordinate deviation value, it is determined that the coordinate transmission accuracy does not meet the requirements, and the verticality of each wire rope and the accuracy of the conductor measurement in the step of obtaining the reflector coordinates are checked to see if they meet the requirements.

3. The construction coordinate transfer method for deep foundation pits according to claim 1, characterized in that, The deep foundation pit is constructed using a layer-by-layer excavation method. As the foundation pit is excavated layer by layer, the step of obtaining the coordinates of the bottom of the foundation pit is performed once for each layer to complete the coordinate transfer from the ground to the bottom of each layer of the foundation pit.

4. The construction coordinate transfer method for deep foundation pits according to claim 3, characterized in that, After the coordinate transfer of the i-th layer of the foundation pit is completed, multiple points are selected on the sidewall of the foundation pit and marked as check points. The coordinates of the check points are measured using a total station at the bottom of the i-th layer of the foundation pit as (X... ij Y ij ), where i represents the i-th layer of foundation pit, and j represents the label of the check point; After the coordinate transfer of the (i+1)th layer of the foundation pit is completed, the coordinates of the check point are measured using a total station at the bottom of the (i+1)th layer of the foundation pit as (X... （i+1）j Y （i+1）j ); The coordinate transfer accuracy of the (i+1)th layer of the foundation pit is checked a second time: the difference in the horizontal coordinate ΔX' is calculated according to formula (3), and the difference in the vertical coordinate ΔY' is calculated according to formula (4). The expressions of formula (3) and formula (4) are as follows: (3) （4）； Compare the difference in the horizontal coordinate ΔX' and the difference in the vertical coordinate ΔY' to determine whether the coordinate transfer accuracy meets the requirements.

5. The construction coordinate transfer method for deep foundation pits according to claim 1, characterized in that, In the preparation step, the plumb bob is placed in a container filled with damping fluid.

6. A coordinate measurement and transfer system, characterized in that, The construction coordinate transfer method according to any one of claims 1-5 includes: A support frame is installed on the side wall of the foundation pit, and a horizontal mounting seat is installed at the end of the support frame. The support frame is used to adjust the levelness of the horizontal mounting seat. A prism having a base, the base being mounted on the horizontal mounting base; A steel wire rope is fixed at the center of the base, and a plumb bob is fixed at the bottom end of the steel wire rope to keep the steel wire rope in a vertical position. A reflector, which is fixed to the steel wire rope; A total station, set at a control point on the ground or at a station at the bottom of the pit, is used to observe the prism or the reflector.

7. The coordinate measurement and transfer system according to claim 6, characterized in that, The support includes a horizontal fixing frame and a supporting diagonal rod; The inner end of the horizontal fixing frame is installed on the side wall of the pit, and the horizontal mounting seat is installed on the outer end of the horizontal fixing frame. The horizontal fixing frame rotates relative to the side wall of the pit to adjust the levelness of the horizontal mounting seat. One end of the support diagonal rod is installed on the horizontal fixed frame, and the other end is installed on the side wall of the foundation pit. The support diagonal rod is a telescopic structure so that the horizontal fixed frame can be rotated relative to the side wall of the foundation pit through the extension and retraction of the support diagonal rod.

8. The coordinate measurement and transfer system according to claim 7, characterized in that, The horizontal fixing frame includes two opposing adjusting brackets with a gap between them. The horizontal mounting base has a mounting hole at its center, which is located above the gap. Each of the adjustment brackets is equipped with a support diagonal rod below it. By adjusting the length of two support diagonal rods, the corresponding adjustment bracket is rotated relative to the pit sidewall, so that the horizontal mounting base is in a horizontal state.

9. The coordinate measurement and transfer system according to claim 7, characterized in that, The supporting diagonal rod includes screws at both ends and a hollow connecting pipe connecting the two screws. One end of each screw is fixed to the pit sidewall and the horizontal fixing frame, respectively, and the other end is threaded to the connecting pipe.

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