A displacement measurement method and system for concrete arch dam

Abstract

The present invention relates to the technical field of dam deformation monitoring, and discloses a method and system for measuring the horizontal displacement of a concrete arch dam, including: obtaining the plane control measurement data of a dam corridor in a concrete arch dam, setting pairs of measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan; selecting the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop to obtain plane control measurement data; performing adjustment and solution on the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement point; using the control point target ball prism target to convert the relative coordinates of the three-dimensional laser scanning point cloud data into the three-dimensional spatial geographic coordinates; and obtaining the horizontal displacement data of the concrete arch dam through the deformation analysis strategy of the point cloud to the point cloud. The present invention can realize the technical transformation of the arch dam horizontal displacement observation from the traditional discrete point observation to the three-dimensional overall observation.

Description

Technical Field

[0001] The invention relates to the technical field of dam deformation monitoring, and in particular to a method and system for measuring the horizontal displacement of a concrete arch dam. Background Art

[0002] Deformation monitoring of concrete arch dams is an extremely important part of the daily operation and maintenance of hydropower stations. Its monitoring items mainly include horizontal displacement of the dam body, vertical displacement, and relative deformation of the weak interlayer and fault of the arch seat. With the rapid development of the current Internet of Things technology, many projects in the deformation monitoring of arch dams are gradually transforming from traditional manual readings to highly intelligent, networked, and integrated automated monitoring methods. The deformation monitoring results can intuitively reflect the operating status of the concrete arch dam, among which the displacement monitoring data is the most intuitive parameter that can reflect the degree of deformation of the arch dam. Typical horizontal monitoring facilities include horizontal displacement monitoring networks, vertical and inverted vertical lines, and intersection points. Vertical displacement monitoring mainly uses vertical displacement monitoring networks and static leveling, and the relative deformation of the weak interlayer and fault of the arch seat is observed using multi-point displacement meters. It should be pointed out that the traditional vertical line system, static leveling, and measurement monitoring methods with total stations as the main monitoring equipment all use single-point observation methods to collect coordinate information of multiple preset points on the dam surface or inside the dam corridor. The displacement of the dam is analyzed by comparing multiple observation data. Due to the limited number of preset displacement monitoring points on the dam surface and inside the corridor, the results of multi-point displacement monitoring are not enough to fully characterize the overall deformation of the dam. In recent years, some scholars have transplanted the vacuum laser deformation monitoring system suitable for straight dams to the deformation monitoring scenario of arch dams, achieving sub-millimeter-level horizontal and vertical displacement monitoring accuracy. However, the construction, installation and maintenance process of such monitoring systems are complex, and the vacuum degree is difficult to ensure, which limits the application and promotion of this method. In addition, at this stage, GNSS technology is also used as a conventional technical means in the deformation monitoring of arch dams. It can achieve uninterrupted and continuous operation around the clock, but this solution has high requirements for the selection of monitoring points. Generally, it can only be deployed at an unobstructed position on the dam top where satellite signals can be received, and the displacement monitoring accuracy is general (typical value 2~5mm).

[0003] At present, non-contact measurement methods represented by three-dimensional laser scanning technology and synthetic aperture interferometry technology are more widely used in deformation monitoring of buildings and slopes. Among them, terrestrial laser scanning (TLS) and ground-based interferometric synthetic aperture radar (GB InSAR) are the two most promising technologies for solving the problem of high-precision deformation monitoring of concrete arch dams. Ground-based InSAR monitoring has high accuracy, but its market price is high at present. Continuous and uninterrupted measurement must be ensured during the monitoring process. In addition, there are practical technical problems that have not been completely solved at this stage, such as phase unwrapping and atmospheric phase compensation, which will affect the monitoring accuracy of this method to a certain extent. Using a terrestrial three-dimensional laser scanner to scan the deformation monitoring target area can quickly obtain a large amount of high-precision point cloud data of the target area. Using an appropriate data comparison method, the two phases of point cloud data are compared to obtain the displacement point cloud data of the monitoring target area.

[0004] In large-area deformation monitoring scenarios including concrete arch dams, the entire project often requires scanning of several stations at different locations in order to obtain comprehensive data covering the monitoring target area. Therefore, high-precision registration and alignment of multi-station data and data from different periods is an important prerequisite for achieving high-precision deformation analysis. Scholars have adopted a variety of means to ensure the registration accuracy between point cloud data, such as introducing control measurement constraints, using target-based registration algorithms, and feature plane-based registration algorithms. However, it should be noted that no matter how accurate and advanced the point cloud registration algorithm is, especially in linear structure scanning scenarios such as dams and tunnel projects, the accumulation of errors caused by registration between multi-station data is often inevitable and cannot be quantified. This error will inevitably affect the accuracy of horizontal displacement deformation monitoring. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for measuring the horizontal displacement of a concrete arch dam, comprising the following steps:

[0006] Step 1: Survey the corridor environment, and set up paired measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan;

[0007] Step 2: Use the full-circle direction observation method to observe in the free station corner intersection mode. Each station has a set number of control measurement point pairs before and after the observation, and there are no less than the set number of common control measurement points between adjacent stations.

[0008] Step 3: Select the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop. The starting point and the control measurement point inside the concrete arch dam corridor form a closed loop to obtain plane control measurement data;

[0009] Step 4: setting a set number of target sphere prisms at each scanning station, sequentially setting a plurality of scanning stations on the center line of the concrete arch dam corridor according to the scanning station spacing, and recording the control measurement point number included in the scanning data of each scanning station;

[0010] Step 5: Perform adjustment and solution on the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points; extract the target sphere prism target from the three-dimensional laser scanning point cloud data of the concrete arch dam corridor, assign the three-dimensional spatial coordinates of the control measurement points obtained by measurement to the corresponding target sphere prism target, and convert the relative coordinates of the three-dimensional laser scanning point cloud data into three-dimensional spatial geographic coordinates;

[0011] Step six, using the point cloud to point cloud deformation analysis strategy, compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system to obtain the horizontal displacement data of the concrete arch dam.

[0012] Furthermore, the corridor environment is surveyed, and paired measurement control points are set at set intervals on the side walls of the concrete arch dam corridor according to the control measurement point arrangement plan, including:

[0013] Control measurement points are set in pairs on the side walls on both sides of the dam corridor inside the concrete arch dam. By installing the measurement control points on the side walls, the centering error introduced by setting up stations at the ground control point positions in conventional plane control measurement can be avoided.

[0014] Furthermore, the full-circle direction observation method is used to observe in a free station corner intersection mode, and each station has a set number of control measurement point pairs before and after the observation, and there are no less than a set number of common control measurement points between adjacent stations, including:

[0015] The interior of the dam corridor in the concrete arch dam is observed using the full-circle observation method in the free station corner intersection mode. Each station has 2 to 3 pairs of control measurement points before and after the observation, totaling 8 to 12 control measurement points, and there are no less than 2 pairs of common control measurement points between two adjacent stations; the common control measurement points are control measurement points shared by two adjacent plane control measurement stations.

[0016] Furthermore, the selection of the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop includes:

[0017] The coordinates of the monitoring points of the rear bridge of the concrete arch dam monitoring system are collected in real time, and the coordinate collection time is recorded. Within the time interval set with the coordinate collection time, the collection of the three-dimensional laser scanning point cloud data of the dam corridor in the concrete arch dam is completed.

[0018] Furthermore, the adjustment and solution of the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points includes:

[0019] The control points in the concrete arch dam corridor are observed by an ultra-high precision total station to obtain the relationship between the control points and their angles. A comprehensive adjustment is performed based on the least squares principle, and the accuracy index of the overall control measurement is determined by the weakest side proportional error.

[0020] Furthermore, the point cloud to point cloud deformation analysis strategy is used to directly compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system to obtain the horizontal displacement data of the concrete arch dam, including:

[0021] The three-dimensional point cloud data of the two-phase concrete arch dam corridor under the same spatial geographic coordinate system are the three-dimensional point cloud data of the concrete arch dam corridor collected under different water level conditions in the reservoir area of ​​the hydropower station;

[0022] In the deformation analysis of point cloud to point cloud, the analysis and comparison strategy based on Hausdorff distance is used to extract the horizontal displacement, and the maximum distance between one set of point cloud and the closest point subset of another set of point cloud is obtained, including the following process:

[0023] The distance between each point in one set of point clouds to be compared and each point in another set of point clouds is calculated, and a bidirectional minimum value set in the calculation result is searched and determined. A maximum value subset is selected from the bidirectional minimum value set for comparison, and the maximum value in the maximum value subset is selected as the distance between the two sets of point clouds.

[0024] A horizontal displacement measurement system for a concrete arch dam, applying the horizontal displacement measurement method for a concrete arch dam, comprising a scanning station module, a cloud data server, a data processing module, a communication module and a data storage module;

[0025] The scanning station module, communication module and data storage module are respectively connected to the data processing module; the cloud data server is communicatively connected to the communication module.

[0026] The beneficial effects of the present invention are as follows: through the horizontal displacement monitoring scheme proposed by the present invention, the accumulated errors in the registration and alignment process of single-period multi-station data and data from different periods can be avoided, and the overall point cloud data with real geographic coordinates of the inspection corridors of each layer of the arch dam can be obtained. By comparing the point cloud data of the two periods under different working conditions, a large amount of point cloud data that can characterize the horizontal displacement of any position in each layer of the corridor inside the concrete arch dam can be obtained. On this basis, the results of different elevation displacements are combined for mathematical statistics and comprehensive analysis, which helps monitoring technicians to intuitively grasp the overall displacement of the arch dam in the horizontal direction from a macro perspective. The technical transformation of the horizontal displacement observation of the arch dam from the traditional discrete point observation to the three-dimensional overall observation is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a displacement measurement method for a concrete arch dam;

[0028] Figure 2 This is a schematic diagram of the connection method of adjacent measuring stations for the 1664m elevation corridor control measurement of a concrete arch dam of a hydropower station;

[0029] Figure 3 This is the overall network diagram of the 1664m elevation corridor control network of a hydropower station concrete arch dam;

[0030] Figure 4 This is a schematic diagram of the layout of the 3D laser field scanning station;

[0031] Figure 5 This is a schematic diagram for extracting the target sphere prism target from the point cloud results;

[0032] Figure 6 It is a schematic diagram of the horizontal displacement analysis process of concrete arch dam based on two-phase point cloud data;

[0033] Figure 7 This is a schematic diagram of the distribution of the dam section, corridor, and vertical line system of a hydropower station;

[0034] Figure 8 Schematic diagram of the basic process of point cloud to point cloud deformation analysis. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0036] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0037] like Figure 1 As shown, a method for measuring the horizontal displacement of a concrete arch dam comprises the following steps:

[0038] Step 1: Survey the corridor environment, and set up paired measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan;

[0039] Step 2: Use the full-circle direction observation method to observe in the free station corner intersection mode. Each station has a set number of control measurement point pairs before and after the observation, and there are no less than the set number of common control measurement points between adjacent stations.

[0040] Step 3: Select the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop. The starting point and the control measurement point inside the concrete arch dam corridor form a closed loop to obtain plane control measurement data;

[0041] Step 4: setting a set number of target sphere prisms at each scanning station, sequentially setting a plurality of scanning stations on the center line of the concrete arch dam corridor according to the scanning station spacing, and recording the control measurement point number included in the scanning data of each scanning station;

[0042] Step 5: Perform adjustment and solution on the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points; extract the target sphere prism target from the three-dimensional laser scanning point cloud data of the concrete arch dam corridor, assign the three-dimensional spatial coordinates of the control measurement points obtained by measurement to the corresponding target sphere prism target, and convert the relative coordinates of the three-dimensional laser scanning point cloud data into three-dimensional spatial geographic coordinates;

[0043] Step six, using the point cloud to point cloud deformation analysis strategy, compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system to obtain the horizontal displacement data of the concrete arch dam.

[0044] Furthermore, the survey of the corridor environment is carried out by setting pairs of measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan, including:

[0045] Control measurement points are set in pairs on the side walls on both sides of the dam gallery inside the concrete arch dam, and the control measurement points on the same side are aligned.

[0046] The full-circle direction observation method is used to observe in the free station corner intersection mode. Each station has a set number of control measurement point pairs before and after the observation, and there are no less than a set number of common control measurement points between adjacent stations, including:

[0047] The interior of the dam corridor in the concrete arch dam is observed using the full-circle observation method in the free station corner intersection mode. Each station has 2 to 3 pairs of control measurement points before and after the observation, totaling 8 to 12 control measurement points, and there are no less than 2 pairs of common control measurement points between two adjacent stations; the common control measurement points are control measurement points shared by two adjacent plane control measurement stations.

[0048] The method of selecting the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop includes:

[0049] The coordinates of the monitoring points of the rear bridge of the concrete arch dam monitoring system are collected in real time, and the coordinate collection time is recorded. Within the time interval set with the coordinate collection time, the collection of the three-dimensional laser scanning point cloud data of the dam corridor in the concrete arch dam is completed.

[0050] The adjustment and solution of the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points includes:

[0051] The control points in the concrete arch dam corridor are observed by an ultra-high precision total station to obtain the relationship between the control points and their angles. A comprehensive adjustment is performed based on the least squares principle, and the accuracy index of the overall control measurement is determined by the weakest side proportional error.

[0052] The point cloud to point cloud deformation analysis strategy is used to directly compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system to obtain the horizontal displacement data of the concrete arch dam, including:

[0053] The three-dimensional point cloud data of the two-phase concrete arch dam corridor under the same spatial geographic coordinate system are the three-dimensional point cloud data of the concrete arch dam corridor collected under different water level conditions in the reservoir area of ​​the hydropower station;

[0054] In the point cloud to point cloud deformation analysis phase, the analysis and comparison strategy based on Hausdorff distance is used to realize the extraction of horizontal displacement. The core of the algorithm is to find the maximum distance between a point cloud set and the nearest point subset of another point cloud set.

[0055] The present invention is achieved by the following steps:

[0056] Step S1: Conduct a survey of the dam corridors at various elevations inside the concrete arch dam, familiarize yourself with the corridor environment, and formulate a reasonable control point layout plan based on the on-site visibility conditions.

[0057] Step S2: Install L-shaped prism rods in pairs at appropriate locations on the side walls of the corridor at certain intervals. The prism rod is 15 cm long and 12 mm in diameter. Use an electric hammer equipped with a 12 mm drill to make holes at appropriate locations on the side walls on both sides. The hole depth should not exceed 10 cm. After injecting an appropriate amount of anchoring glue into the hole, insert the prism rod to ensure that the prism installation end is vertically upward. The hole making position must meet the requirements of front and rear visibility in the free station multi-survey corner observation mode after the prism is mounted on the wall.

[0058] Step S3: The internal plane control network of the corridor is observed by the full-circle observation method according to the corner intersection method of the free measuring stations. Each measuring station needs to observe 2 to 3 pairs of control points in front and behind, totaling 8 to 12 control points. At least 2 pairs (4) of common control points are guaranteed to exist between two adjacent measuring stations.

[0059] Step S4: Select the monitoring point of the rear bridge of the original monitoring system of the concrete arch dam as the starting point of the control measurement closed loop, forming a closed loop consisting of the sustainable observation point of the rear bridge and the internal plane control point of the dam corridor.

[0060] Step S5: Before the 3D laser scanning operation, the target prism needs to be installed. Four target prisms are arranged at each station, divided into two rows, front and back, according to the scanning direction, and two in each row are installed at the control measurement points on the corridor side wall.

[0061] Step S6: The three-dimensional laser scanning field stations of each elevation corridor of the dam are arranged near the center line of the tunnel and in the middle of every two rows of target sphere prisms. The principle is to ensure that the point cloud data of the target sphere prism can be recorded clearly and without obstruction. The spacing between the scanning stations is flexibly adjusted, generally controlled between 10 and 40 meters. Each station is scanned at a high resolution and high quality level (for example, 1 / 4 resolution and 2x quality mode in the FARO S350 scanner). During the on-site scanning process, the control points on the side walls of the corridor must be named according to the control measurement link, and the control point numbers involved in the scanning of each station must be recorded.

[0062] Step S7: In the single-phase data processing link, the plane control measurement data is first adjusted and solved to obtain the accurate three-dimensional spatial coordinates of each control point. Then the target ball prism target is extracted from the three-dimensional laser scanning point cloud data, and the high-precision control measurement results are brought into the three-dimensional laser scanning point cloud data through the target ball prism to realize the transformation of the local coordinate system of the scanned point cloud into the real geographic coordinate system.

[0063] Step S8: After obtaining the point cloud data of the concrete arch dam corridor under two different working conditions according to steps S1 to S7, a cloud to cloud (C2C) deformation analysis strategy is used to directly compare the point cloud data of the two phases. Based on the three-dimensional point cloud comparison results, the extraction of horizontal displacement, mathematical statistics and the output of deformation analysis results are realized.

[0064] For step 2: By installing the measurement control points on the side wall, the centering error introduced by setting up the station at the ground control point position in the conventional plane control measurement can be avoided. The installation effect of the prism rod and prism is shown in the figure below.

[0065] For step 3: plane control measurement, it is recommended to use the most accurate automated observation equipment, such as Leica TM50 and TM60 total stations, to ensure that the angle measurement accuracy reaches ±0.5", and under the control of the onboard program, it can realize automatic aiming, reading and recording, and judge the tolerance, so as to eliminate the manual observation error to the maximum extent. The details of the internal observation network of the corridor of the control measurement scheme proposed in this invention are shown below Figure 2 .

[0066] For step 4: In a typical concrete arch dam scenario, due to the limitations of external site conditions, the external control measurement of the corridor can generally only participate in the closed loop in the form of a single conductor. The starting point coordinates are provided by the power plant management department. The three-dimensional laser test and supporting control measurement operation window should be as close to the starting point coordinate collection time point as possible to avoid measurement errors that may be caused by differences in operation time. Figure 3 .

[0067] For step 5: This operation method can ensure that adjacent measuring stations share two target prisms within a range of no more than 20m, that is, adjacent measuring stations share a pair of control points. Figure 3 .

[0068] Regarding steps 6 and 7: The high-resolution and high-quality gears are selected for the 3D laser scanning operation to ensure that the point cloud data has sufficient density and point position accuracy. In the 3D laser point cloud data processing stage, the target sphere prism targets are extracted from the scanning data of each station to ensure that the number of targets picked up in the cloud data of each station is not less than 3, and then the high-precision control point coordinates obtained in the plane control measurement stage are assigned to the corresponding target sphere prism targets to realize the transformation of the local coordinate system of the scanned point cloud into the real geographic coordinate system, thereby accurately reflecting the corridor location information and internal details. Figure 4 The schematic diagram of the 3D laser field scanning station layout is shown in the figure; the target prism object and its extraction in the point cloud data, such as Figure 5 The target sphere prism target is extracted in the point cloud results shown.

[0069] Regarding step 8: The horizontal displacement monitoring scheme proposed in the present invention is mainly used in the internal corridor environment of concrete arch dams. As mentioned above, the maximum distance between the three-dimensional laser measuring stations in the corridor does not exceed 40m, which is within the optimal working range of the three-dimensional laser scanner's ranging accuracy. In addition, the internal environment of the corridor is relatively simple and has less interference. Through the point cloud classification algorithm and a simple filtering and denoising process, a high-precision point cloud data set that only retains the corridor side walls can be obtained. And we ensure the density of the point cloud by scanning at a high-resolution gear. Taking into account the factors of computational efficiency, we chose to use the C2C scheme to compare the two phases of point cloud data. Figure 6The horizontal displacement analysis process of concrete arch dam based on two-phase point cloud data proposed in this invention

[0070] Implementation Cases:

[0071] like Figure 7 The diagram of the distribution of the dam sections, corridors, and vertical line systems of a hydropower station is shown in the figure. The dam of a hydropower station is a concrete hyperbolic arch dam with a dam height of 305.00m, a dam crest elevation of 1885.00m, a dam crest concrete thickness of 16m, a dam foundation elevation of 1580.00m, and a concrete thickness of 63m, corresponding to a thickness-to-height ratio of 0.207. The dam consists of 26 dam sections, and there are 5 layers of horizontal corridors inside the dam, with corresponding elevations of 1829.00m, 1778.00m, 1730.00m, 1664.00m, and 1601.00m, respectively. The forward and reverse vertical line systems used to observe horizontal displacement of the dam are installed in 1#, 5#, 9#, 11#, 13#, 16#, 19#, and 23# dam sections, respectively.

[0072] The 3D laser scanning data of the hydropower station dam corridor and the supporting control measurement results were collected in May 2023 (before the reservoir was filled with water) and November (when the reservoir was full of water). A total of 163 station cloud data were collected in the two phases. The technical indicators of the plane control measurement solution are shown in Table 1.

[0073] Table 1 Plane control measurement solution results

[0074]

[0075] The achievement of high-precision plane control measurement results ensures the position accuracy of subsequent three-dimensional laser point cloud data, and is the most important prerequisite for extracting the horizontal displacement of the arch dam based on point cloud data. By comparing the early (May 2023) low-water level reference data with the late high-water level (November 2023) test data, a large amount of displacement point cloud data corresponding to each layer of corridor during the reservoir storage process was obtained. On this basis, the stress and deformation of the dam at different elevations and different parts in three-dimensional space were obtained. We merged the downstream dam surface point cloud model obtained by three-dimensional laser scanning with the horizontal displacement point cloud data of each corridor, thereby realizing a clear and intuitive display of the overall displacement of a hydropower station dam during the reservoir storage process.

[0076] The effectiveness of the observation scheme proposed in this invention can be demonstrated by comparing it with the results of traditional horizontal displacement monitoring methods (vertical line system). The comparison results of the 1829 and 1778 m elevation corridors are taken as an example, see Table 2.

[0077] Table 2 Comparison results of 1829 and 1778m elevation corridors

[0078]

[0079] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for measuring the horizontal displacement of a concrete arch dam, characterized in that: The steps include: Step 1: Survey the corridor environment, and set up paired measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan; Step 2: Use the full-circle direction observation method to observe in the free station corner intersection mode. Each station has a set number of control measurement point pairs before and after the observation, and there are no less than the set number of common control measurement points between adjacent stations. Step 3: Select the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop. The starting point and the control measurement point inside the concrete arch dam corridor form a closed loop to obtain plane control measurement data; Step 4: setting a set number of target sphere prisms at each scanning station, sequentially setting a plurality of scanning stations on the center line of the concrete arch dam corridor according to the scanning station spacing, and recording the control measurement point number included in the scanning data of each scanning station; Step 5: Perform adjustment and solution on the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points; extract the target sphere prism target from the three-dimensional laser scanning point cloud data of the concrete arch dam corridor, assign the three-dimensional spatial coordinates of the control measurement points obtained by measurement to the corresponding target sphere prism target, and convert the relative coordinates of the three-dimensional laser scanning point cloud data into three-dimensional spatial geographic coordinates; Step 6, using a point cloud to point cloud deformation analysis strategy to compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system, and obtain the horizontal displacement data of the concrete arch dam; The survey of the corridor environment is to set up pairs of measurement control points at set intervals on the side walls on both sides of the concrete arch dam corridor according to the control measurement point arrangement plan, including: Control measurement points are set in pairs on the side walls on both sides of the dam corridor inside the concrete arch dam. By installing the measurement control points on the side walls, the centering error introduced by setting up stations at the ground control point positions in conventional plane control measurement can be avoided. The full-circle direction observation method is used to observe in the free station corner intersection mode. Each station includes a set number of control measurement points before and after the observation, and there are no less than a set number of common control measurement points between adjacent stations, including: The interior of the dam corridor in the concrete arch dam is observed by the full-circle direction observation method in the free station corner intersection mode. Each station has 2 to 3 pairs of control measurement points before and after the observation, totaling 8 to 12 points, and there are no less than 2 pairs of common control measurement points between two adjacent stations; the common control measurement points are the control measurement points shared by two adjacent plane control measurement stations; The method of selecting the monitoring point of the rear bridge of the original concrete arch dam monitoring system as the starting point of the control measurement closed loop includes: The coordinates of the monitoring points of the rear bridge of the concrete arch dam monitoring system are collected in real time, and the coordinate collection time is recorded. Within the time interval set with the coordinate collection time, the collection of the three-dimensional laser scanning point cloud data of the dam corridor in the concrete arch dam is completed; the adjustment and solution of the plane control measurement data to obtain the three-dimensional spatial geographic coordinates of the control measurement points includes: The control points in the concrete arch dam corridor are observed by the ultra-high precision total station to obtain the relationship between the control points and the angles. The overall adjustment is carried out based on the least squares principle, and the accuracy index of the overall control measurement is determined by the weakest side proportional error. The point cloud to point cloud deformation analysis strategy is used to directly compare the three-dimensional point cloud data of the two phases of concrete arch dam corridors in the same spatial geographic coordinate system to obtain the horizontal displacement data of the concrete arch dam, including: The three-dimensional point cloud data of the two-phase concrete arch dam corridor under the same spatial geographic coordinate system are the three-dimensional point cloud data of the concrete arch dam corridor collected under different water level conditions in the reservoir area of ​​the hydropower station; In the deformation analysis of point cloud to point cloud, the analysis and comparison strategy based on Hausdorff distance is used to extract the horizontal displacement, and the maximum distance between one set of point cloud and the closest point subset of another set of point cloud is obtained, including the following process: Calculate the distance between each point in one set of point clouds to be compared and each point in another set of point clouds, search and determine the bidirectional minimum value set in the calculation results, select a maximum value subset in the bidirectional minimum value set for comparison, and select the maximum value in the maximum value subset as the distance between the two sets of point clouds; By comparing the early low-water level reference data with the late high-water level test data, we obtained a large amount of displacement point cloud data corresponding to each layer of corridors during the reservoir water storage process. On this basis, we obtained the stress and deformation conditions of the dam at different elevations and different parts in three-dimensional space. The downstream dam surface point cloud model obtained by three-dimensional laser scanning was integrated with the horizontal displacement point cloud data of each corridor to achieve a clear and intuitive display of the overall displacement of a hydropower station dam during the reservoir water storage process.

2. A horizontal displacement measurement system for a concrete arch dam, characterized in that: A method for measuring the horizontal displacement of a concrete arch dam according to claim 1 is applied, comprising a scanning station module, a cloud data server, a data processing module, a communication module and a data storage module; The scanning station module, communication module and data storage module are respectively connected to the data processing module; the cloud data server is communicatively connected to the communication module.

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