Karst area impact hole pouring pile deviation monitoring method

Abstract

The present application relates to the field of civil engineering construction monitoring, and particularly relates to a kind of karst area impact hole-forming bored pile deviation monitoring method, comprising the following steps, using BIM modeling method, based on the diameter of steel casing in karst area construction site, the BIM model of impact hole-forming bored pile is constructed;Three-dimensional real scene model of karst area construction site is constructed by unmanned aerial vehicle oblique photography;Based on the same coordinate system, the BIM model and the three-dimensional real scene model are fused, the fusion model is obtained, and the horizontal distance between the impact hole-forming bored pile model and the steel casing model is measured in the fusion model;The horizontal distance between the impact hole-forming bored pile model and the steel casing model is used to monitor the deviation distance of the impact hole-forming bored pile in karst area. The scheme of the present application can monitor the deviation degree of the position of the impact hole-forming bored pile in karst area at any time, and the monitoring process is convenient, and does not affect the normal construction of the impact hole-forming bored pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of civil engineering construction monitoring, and particularly relates to a method for monitoring the deviation of a bored pile in a karst area. BACKGROUND

[0002] The reinforced concrete bored pile is the most commonly used foundation in bridge engineering. The specification has strict requirements for the pile position, and the deviation of the bent pile is not greater than 50 mm, and the maximum deviation is not greater than 100 mm; the deviation of the pile of the pile cap is not greater than 100 mm. In the karst area, the most commonly used method for the construction of the reinforced concrete bored pile foundation is the impact hole forming method. This method has simple equipment, low cost, is suitable for various cover layers, and can conveniently and effectively treat karst phenomena such as karst caves, fissures, half rocks and uneven rock surfaces in combination with backfilling of stone and clay, and has obvious advantages in terms of technology and economy. However, in the construction of the pile foundation in the karst development area, extreme weather such as floods and heavy rains often occurs, and the working environment is poor. There is often a cover layer on the rock stratum, and when the bored pile enters the rock and reaches the bottom of the karst cave, the drill deviates to the side with softer rock due to the difference in the hardness of the bottom surface of the pile hole, and it is necessary to repeatedly backfill the stone to correct it. At this time, the steel wire rope hanging the drill also deviates to one side, and the tension of the steel wire rope generates a horizontal force on the drill rack. When the cover layer supporting the drill rack is weak, the rack and the casing are prone to horizontal deviation, thereby causing the deviation of the bored pile. Although the deviation of the bored pile beyond the allowable value of the specification does not often occur, once it occurs, it is troublesome to treat, and increases the construction period and cost.

[0003] For example, a bent pier is used in a certain highway bridge, and one bored pile foundation is arranged under each bent pier. During the detection process after the pile is formed, it is found that the bored pile foundation deviates by 15 cm in the transverse direction of the bridge and by 18 cm in the longitudinal direction of the bridge, and the allowable value of the specification is 5 cm. The deviation value far exceeds the allowable value of the specification, and the bored pile is finally reformed, which affects the construction period by 2.5 months. For another example, the pier of a certain city bridge uses a pile cap foundation, and three rows of bored pile foundations are arranged under each pile cap in the longitudinal direction of the bridge, and four rows of bored pile foundations are arranged in the transverse direction of the bridge. The bedrock surface of the bridge is uneven, the karst development is strong, and the bedrock is covered with red clay. During the detection of the pile foundation by excavating the foundation pit, the deviation of most of the bored pile foundations exceeds the allowable value of the specification, and the maximum deviation is 55 cm, which far exceeds the allowable value of 10 cm of the specification. Finally, the size of the pile cap is expanded by 60 cm outward, which increases the construction cost.

[0004] In summary, it is difficult to detect and find the deviation of the pile foundation during the bored pile hole forming construction process, and the treatment is complicated after the bored pile construction is completed, which affects the construction period, especially the construction period of the whole bridge, and increases the cost.

[0005] The most convenient treatment method for the deviation of the impact hole pouring pile in the karst development area is to monitor the deviation of the impact hole pouring pile in the construction process, and when it is found that the deviation of the impact hole pouring pile exceeds the allowable value, the stone and concrete are refilled, the steel casing is reburied, and the hole is reformed. However, the construction environment of the bridge impact hole pouring pile is poor, the deviation of the pile foundation is measured by manual measurement during the impact hole pouring pile forming process, only the diameter of the steel casing can be detected, the monitoring workload is large, the error is large, the construction is affected, and the operation difficulty is large. Therefore, it is necessary to provide a new karst area impact hole pouring pile deviation monitoring method to overcome the shortcomings of the prior art. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a karst area impact hole pouring pile deviation monitoring method, which can monitor the deviation degree of the impact hole pouring pile in the karst area at any time, and the monitoring process is convenient and does not affect the normal construction of the impact hole pouring pile.

[0007] The technical solution of the present application to solve the above technical problem is as follows: a karst area impact hole pouring pile deviation monitoring method, comprising the following steps,

[0008] Step 1, using BIM modeling method, constructing BIM model of impact hole pouring pile based on diameter of steel casing in karst area construction site;

[0009] Step 2, constructing three-dimensional real scene model of karst area construction site by unmanned aerial vehicle oblique photography;

[0010] Step 3, based on the same coordinate system, fusing the BIM model and the three-dimensional real scene model to obtain a fusion model, and measuring the horizontal distance between the impact hole pouring pile model and the steel casing model in the fusion model;

[0011] Step 4, monitoring the deviation distance of the karst area impact hole pouring pile by the horizontal distance between the impact hole pouring pile model and the steel casing model.

[0012] The principle of the present application is: a BIM model of impact hole pouring pile is built, an unmanned aerial vehicle oblique photography is used to construct a three-dimensional real scene model of the construction site, the two models are fused in the same coordinate system, and the horizontal distance between the impact hole pouring pile model and the steel casing model in the fusion model is measured, which is the deviation degree of the impact hole pouring pile in the karst area.

[0013] Specifically,

[0014] Step 1, a BIM model of the impact hole pouring pile is constructed based on the diameter of the steel casing in the construction site in the karst area by using the BIM modeling method, and the position of the BIM model of the impact hole pouring pile is the position required by the design. The impact hole pouring pile belongs to a concealed project, and in order to ensure the quality, the diameter of the steel casing is 20cm larger than that of the impact hole pouring pile, so the actual diameter of the impact hole pouring pile after being formed is also 20cm larger than the designed diameter. The diameter of the BIM model of the impact hole pouring pile is taken as the diameter of the steel casing, so the diameter of the BIM model of the impact hole pouring pile is equal to the actual diameter of the impact hole pouring pile.

[0015] Step 2, a three-dimensional real scene model of the construction site in the karst area is constructed by using the tilt photography of the unmanned aerial vehicle. From the three-dimensional real scene model, the position of the steel casing in the construction process of the impact hole pouring pile can be measured, and the position of the steel casing at the end hole is the actual position of the impact hole pouring pile.

[0016] Step 3, the BIM model and the three-dimensional real scene model are fused based on the same coordinate system to obtain a fusion model, and the horizontal distance between the impact hole pouring pile model and the steel casing model in the fusion model is measured; wherein the impact hole pouring pile model in the fusion model is from the BIM model, and the steel casing model in the fusion model is from the three-dimensional real scene model.

[0017] Step 4, the horizontal distance between the impact hole pouring pile model and the steel casing model is used to monitor the deviation distance of the impact hole pouring pile in the karst area.

[0018] In summary, the impact hole pouring pile position deviation monitoring method can monitor the deviation degree of the impact hole pouring pile position in the karst area, and the unmanned aerial vehicle tilt photography is used, so that the monitoring process is convenient and does not affect the normal construction of the impact hole pouring pile.

[0019] The impact hole pouring pile position deviation monitoring method can monitor the deviation degree of the impact hole pouring pile position in the karst area, and the unmanned aerial vehicle tilt photography is used, so that the monitoring process is convenient and does not affect the normal construction of the impact hole pouring pile.

[0020] On the basis of the above technical solutions, the present application can also be improved as follows.

[0021] Further, the specific process of constructing the BIM model of the impact hole pouring pile is as follows,

[0022] The intersection method in the Openroads designer software is used to draw the bridge plane line, and the bridge plane line is obtained;

[0023] The longitudinal section is drawn on the bridge plane line by inputting the slope, pile number and vertical curve radius;

[0024] The bridge plane line with the longitudinal section drawn is introduced into the OpenBridges Modeler software, and the cross line is placed according to the number and distance of the bridge;

[0025] The custom template library file in the installation directory of the OpenBridges Modeler software is extracted into the Miscrostation, and the impact hole pouring pile is drawn in the Miscrostation according to the diameter of the steel casing; the position of the impact hole pouring pile in the cross line is defined by the way of customizing the origin in the origin command, and the three-dimensional BIM template of the impact hole pouring pile is formed;

[0026] The three-dimensional BIM template of the impact hole pouring pile is placed in the OpenBridges Modeler, and the BIM model of the impact hole pouring pile is obtained.

[0027] The beneficial effects of the further scheme are that for conventional bridges, Openroads designer and Miscrostation have ready-made templates, which can quickly model. For special bridges, the model can be saved as a template for easy and fast editing and repeated use.

[0028] Further, the diameter of the impact hole pouring pile in the BIM model is the diameter of the steel casing in the construction site, and the pile top elevation of the impact hole pouring pile in the BIM model is the top surface elevation of the steel casing.

[0029] The beneficial effects of the further scheme are that in actual construction, the diameter of the steel casing is about 20 cm larger than the design diameter of the impact hole pouring pile, and the elevation of the top of the casing is also higher than the pile top elevation of the impact hole pouring pile. In order to facilitate the measurement of the horizontal distance between the impact hole pouring pile model and the steel casing model, the diameter of the impact hole pouring pile in the BIM model is the diameter of the steel casing, and the top elevation of the impact hole pouring pile is the top elevation of the steel casing. The BIM model of the impact hole pouring pile has the same diameter and top elevation as the steel casing, which facilitates the fusion of the BIM model and the three-dimensional real scene model, and the measurement of the deviation of the impact hole pouring pile.

[0030] Further, the specific process of constructing the three-dimensional real scene model of the construction site in the karst area is,

[0031] Semi-permanent image control points are arranged around the construction site in the karst area;

[0032] According to the regional topography, range and endurance of the unmanned aerial vehicle of the construction site, the flight route is planned and the flight parameters are set;

[0033] The unmanned aerial vehicle carrying a five-lens oblique photogrammetry camera performs field aerial survey according to the flight route and flight parameters, and obtains aerial survey data with image control point images;

[0034] Based on aerial triangulation, a three-dimensional scene modeling is performed according to the aerial survey data to generate the three-dimensional real scene model of the construction site in the karst area.

[0035] The beneficial effect of the further scheme is that the semi-permanent photo control point can be used throughout the construction phase; the unmanned aerial vehicle with a five-lens oblique photogrammetry camera performs field aerial survey according to the flight route and flight parameters to obtain aerial survey data with photo control point images, and the aerial survey efficiency is high, and 10 minutes is enough to complete the aerial survey of a bridge construction site; the aerial triangulation has high calculation efficiency, and the modeling can be completed within several hours.

[0036] Further, based on aerial triangulation, the specific steps of three-dimensional scene modeling according to the aerial survey data are,

[0037] According to the aerial survey data, the homonymous points between adjacent images are obtained and image matching is performed to obtain the parallax and depth information between adjacent images;

[0038] Based on the parallax and depth information between adjacent images, the aerial relationship between adjacent images is calculated by combining the position and attitude information of the images using photogrammetry method;

[0039] Based on the aerial relationship between adjacent images, all pixels in the images are discretized in the three-dimensional space through image dense matching to obtain a plurality of discrete points with color information; and the plurality of discrete points with color in the three-dimensional space form a color point cloud;

[0040] The plurality of discrete points in the color point cloud are connected by a TIN triangular network method to form a plurality of triangular facets;

[0041] The plurality of triangular facets form a triangular network, and the triangular network is taken as a basic model;

[0042] According to the spatial position of the color point cloud points, the color information of the points is mapped to the surface of the basic model to obtain an initial three-dimensional real scene model;

[0043] The initial three-dimensional real scene model is refined and corrected to obtain the three-dimensional real scene model of the construction site in the karst area.

[0044] The beneficial effect of the further scheme is that due to the aerial blind area, ground object reflection and different aerial survey time, etc., the three-dimensional real scene model has hollow areas, texture deformation, model suspension, etc., which is inevitable for real scene three-dimensional modeling based on oblique photography technology, and the above method is convenient for repairing the initial three-dimensional real scene model.

[0045] Further, in the flight parameters, the heading overlap degree is not less than 75%, the lateral overlap degree is not less than 60%, the unmanned aerial vehicle adopts close-range photogrammetry, and the flight height range is 15-40 m.

[0046] The beneficial effect of the further scheme is that the deviation limit of the pile foundation is 5 cm or 10 cm, so the accuracy requirement of the unmanned aerial vehicle oblique photography is higher, the planar accuracy of the unmanned aerial vehicle oblique photography is required to be about 2 cm, so the unmanned aerial vehicle adopts close-range photography, the distance of the unmanned aerial vehicle from the ground is 15-40 m, and the distance of the unmanned aerial vehicle from the ground is less than 40 m to shoot high-definition photos and ensure the accuracy; the distance of the unmanned aerial vehicle from the ground is greater than 15 m for safety in field shooting.

[0047] Further, based on the same coordinate system, the BIM model and the three-dimensional real scene model are fused to obtain a fusion model, and the specific steps of measuring the horizontal distance between the impact hole pouring pile model and the steel casing model in the fusion model are,

[0048] The three-dimensional real scene model of the construction site in the karst area is imported into MicroStation in FBX format, and the three-dimensional real scene model of the construction site in the karst area and the BIM model of the impact hole pouring pile are placed in the same coordinate space of MicroStation to obtain a fusion model;

[0049] The measurement function in MicroStation is used to select the impact hole pouring pile model and the steel casing model in the fusion model for distance measurement to obtain the horizontal distance between the impact hole pouring pile model and the steel casing model.

[0050] The beneficial effect of the further scheme is that the horizontal position coordinates of the BIM model and the steel casing three-dimensional real scene model can be queried, but the impact hole pouring pile is large in size and small in deviation limit, and the manufacturing error and deformation of the steel casing can affect the horizontal position coordinates directly queried from the three-dimensional real scene model. The further scheme can ensure the accuracy of the horizontal distance between the impact hole pouring pile model and the steel casing model, and can also intuitively reflect the relative distance between the impact hole pouring pile hole forming position and the design position.

[0051] Further, after monitoring the deviation distance of the impact hole pouring pile in the karst area, a corresponding treatment method is selected in the construction site according to the offset distance between the impact hole pouring pile and the steel casing; specifically,

[0052] If the horizontal distance between the impact hole pouring pile model and the steel casing model is less than or equal to X1, the center of the impact hole pouring pile reinforcement cage is aligned with the design center of the impact hole pouring pile when the impact hole pouring pile reinforcement cage is installed;

[0053] If the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model is within the range of (X1, X2), then when installing the impact-drilled cast-in-place pile reinforcement cage, the center of the impact-drilled cast-in-place pile reinforcement cage will be offset towards the offset direction of the steel casing. The distance between the center of the impact-drilled cast-in-place pile reinforcement cage and the center of the steel casing is the difference between the offset distance of the steel casing and X1.

[0054] If the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model is greater than X2, then backfill with rubble and clay and re-drill holes before installing the foundation reinforcement cage of the reinforced concrete pile.

[0055] Where X1 and X2 are preset values, X1 is half the difference between the diameter of the steel casing and the design diameter of the impact-drilled cast-in-place pile, and X2 is the sum of X1 and the allowable deviation of the pile foundation.

[0056] The advantages of adopting the above-mentioned further solution are: monitoring the deviation of the steel casing during the drilling process of the impact-drilled cast-in-place pile allows for timely determination of the pile hole deviation. Furthermore, different treatment methods can be selected based on the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model, making it economical and effective.

[0057] Furthermore, when the allowable deviation of the pile foundation is 5cm, X1 and X2 are taken as 10cm and 15cm respectively; when the allowable deviation of the pile foundation is 10cm, X1 and X2 are taken as 10cm and 20cm respectively.

[0058] The beneficial effects of adopting the above-mentioned further scheme are: the allowable deviation values ​​of the pile foundations of the frame pile and the pile foundation group are different. According to the allowable deviation value of the pile foundation, X2 adopts different preset values, allowing the pile foundation to have a certain displacement less than the allowable deviation value of the pile foundation, which is in line with the principle of economy. Attached Figure Description

[0059] Figure 1 This is a flowchart of a method for monitoring the deviation of impact-drilled cast-in-place piles in karst areas according to the present invention;

[0060] Figure 2 A top-view diagram of the BIM model of the impact bored pile and the three-dimensional reality model of the construction site in the karst area;

[0061] Figure 3 This is a schematic diagram showing the misalignment between the impact-grown bored pile and the steel casing. Detailed Implementation

[0062] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0063] like Figure 1 As shown in this embodiment, the method for monitoring the deviation of percussion bored piles in karst areas includes the following steps:

[0064] Step 1, using BIM modeling method, based on the diameter of the steel casing in the karst area construction site, the BIM model of the impact hole filling pile is constructed;

[0065] Step 2, the three-dimensional real scene model of the karst area construction site is constructed by unmanned aerial vehicle oblique photography;

[0066] Step 3, based on the same coordinate system, the BIM model and the three-dimensional real scene model are fused to obtain a fusion model, and the horizontal distance between the impact hole filling pile model and the steel casing model is measured in the fusion model;

[0067] Step 4, the horizontal distance between the impact hole filling pile model and the steel casing model is used to monitor the deviation distance of the impact hole filling pile in the karst area.

[0068] The following will be described in detail.

[0069] Construction of BIM model of impact hole filling pile:

[0070] According to the design, first of all, a plurality of irregular polygons and path curves are drawn in MicroStation, and then the BIM model of the impact hole filling pile is constructed by using the commands such as stretching structure and placing path. The BIM model of the impact hole filling pile is constructed by using the Bentley series software in this embodiment.

[0071] In this specific embodiment, the specific process of constructing the BIM model of the impact hole filling pile is as follows:

[0072] (1) The bridge plane line is drawn by using the intersection method in the OpenRoads Designer software to obtain the bridge plane line; specifically, the bridge plane line is drawn by inputting three point coordinates and curve elements.

[0073] (2) The longitudinal section is drawn on the plane line, which is completed by inputting the slope, pile number and vertical curve radius.

[0074] (3) After the bridge plane line is drawn, the bridge plane line with longitudinal section is imported into the OpenBridgesModeler software, the span line is placed according to the number of bridge spans and distance, so as to accurately position the position of the impact hole filling pile.

[0075] (4) Find the cel format file, that is, the custom template library file, under the installation directory of the OpenBridges Modeler software, and extract the custom template library file to the Miscrostation to establish the impact hole pouring pile three-dimensional BIM template. The method is to first obtain the diameter of the steel casing, draw the two-dimensional section of the impact hole pouring pile, and then stretch the section into the three-dimensional shape of the impact hole pouring pile by using the stretching structure; for simple regular shapes, the corresponding regular body can be directly drawn in the intelligent entity, for example, a cylinder can be directly drawn by inputting the diameter and height; the placed regular body can be one or more, and if it is more, the various regular bodies only need to be combined into one body by using the Boolean sum command to achieve the drawing of the impact hole pouring pile as a whole; then the placement path is defined in the origin command by customizing the origin, that is, the position of the impact hole pouring pile template in the layout line, the template drawing is completed, and the impact hole pouring pile template is placed in the Open bridges modeler to obtain the BIM model of the impact hole pouring pile.

[0076] In the specific embodiment, the diameter of the impact hole pouring pile in the BIM model is the diameter of the steel casing in the construction site, and the pile top elevation of the impact hole pouring pile in the BIM model is the top surface elevation of the steel casing.

[0077] Before the impact hole pouring pile is formed, a steel casing needs to be buried to play the role of positioning, wall protection and protection of the hole. The diameter of the steel casing is larger than the design diameter of the impact hole pouring pile by about 20 cm. Therefore, the hole diameter of the impact hole pouring pile is also larger than the design diameter of the impact hole pouring pile by about 20 cm. When the BIM model of the impact hole pouring pile is established in the embodiment, the diameter of the impact hole pouring pile is taken as the diameter of the steel casing, which is convenient for monitoring the deviation of the pile foundation hole. In addition, in the pile foundation construction process of bridge engineering, artificial island construction and steel structure platform erection are needed as the construction platform, and the top elevation of the steel casing is generally higher than the design elevation of the pile top. The design elevation of the pile top of the impact hole pouring pile in the BIM model is taken as the top elevation of the steel casing, which is also convenient for monitoring the deviation of the pile foundation hole.

[0078] Construction of three-dimensional real scene model:

[0079] In the specific embodiment, the specific process of constructing the three-dimensional real scene model of the construction site is,

[0080] (1) In the construction site periphery, semi-permanent like control points are laid out; the like control points are real coordinate points with signs established in the measured area by using RTK or total station (mostly using RTK) when unmanned aerial vehicle surveying is carried out. Through the like control points, the coordinate points surveyed by unmanned aerial vehicle can be corrected, so as to complete the unmanned aerial vehicle surveying. The like control points laid out uniformly in the construction site can realize the matching of the model and the real geodetic coordinate, and realize the control of the model precision.

[0081] (2) According to the regional topography, range of the construction site and the endurance ability of the unmanned aerial vehicle, the flight route is planned and the flight parameters are set, such as flight height, heading overlap and lateral overlap. In order to realize the precision of less than 2cm, the following measures are taken: in the process of unmanned aerial vehicle surveying, the heading overlap is ensured to be not less than 75% and the lateral overlap is ensured to be not less than 60%; the unmanned aerial vehicle adopts close photogrammetry with the height of 15m-40m.

[0082] (3) The unmanned aerial vehicle with five-lens oblique photogrammetry camera is controlled to carry out field surveying according to the flight route, so as to obtain the surveying data with like control point images; wherein, the surveying data includes aerial photographs, GPS data, like control point data and the like.

[0083] (4) Based on aerial triangulation, the three-dimensional scene modeling is carried out according to the surveying data, so as to generate the three-dimensional real scene model.

[0084] Aerial triangulation, also called analytical aerial triangulation, refers to the determination of the exterior orientation elements of all images in the region by photogrammetric analysis. In the traditional photogrammetry, this is realized by measuring the point position, that is, the exterior orientation elements of the image are solved by using the measured image point coordinates and a small amount of control point geodetic coordinates, so that the known points are increased to not less than 4 in each model, and then the exterior orientation elements of the image are solved by using these known points, so that the analytical aerial triangulation is also called photogrammetry encryption or aerial triangulation encryption.

[0085] The principle of generating a three-dimensional real scene model based on aerial triangulation is as follows: first, points with sharp color or texture changes in the image (obtained by a UAV) are extracted, and these points are referred to as feature points; second, the same feature points in the image due to the degree of overlap are used to realize the correlation of feature information of different photos; third, the camera internal parameters, position and attitude during imaging are adjusted to minimize the intersection error of the feature points in the three-dimensional space; the image with the adjusted camera position and attitude is taken as the output, and pixel-by-pixel matching is performed to generate a dense three-dimensional point cloud; a triangular net is constructed based on the three-dimensional point cloud; finally, the photos that capture the triangular facets are found, the best shooting angle is selected according to certain rules, the triangular facets are colored, and a three-dimensional real scene model is generated. In this embodiment, the specific steps of three-dimensional scene modeling based on aerial triangulation according to aerial survey data are as follows:

[0086] Obtaining the same name points between adjacent images according to aerial survey data and performing image matching to obtain the parallax and depth information between adjacent images;

[0087] Based on the parallax and depth information between adjacent images, the aerial relationship between adjacent images is calculated by using photogrammetry method in combination with the position and attitude information of the images;

[0088] Based on the aerial relationship between adjacent images, all the pixels in the images are discretized in the three-dimensional space through image dense matching to obtain a plurality of discrete points with color information; the plurality of discrete points with color information form a color point cloud in the three-dimensional space; the color point cloud has both the geometric characteristics of the point cloud and the color information of each point;

[0089] The plurality of discrete points in the color point cloud are connected by TIN triangular net construction to form a plurality of triangular facets;

[0090] The plurality of triangular facets form a triangular net, and the triangular net is taken as a basic model, which is a white model; according to the spatial position of the points of the color point cloud, the color information of the points is mapped to the surface of the basic model to obtain an initial three-dimensional real scene model; the color information of the points is mapped to the surface of the basic model to exert the color attribute of the color point cloud, so that the initial three-dimensional real scene model has both geometric appearance and real color texture.

[0091] Due to problems such as aerial photography blind area, ground object reflection and different aerial photography time, the three-dimensional real scene model has hollow areas, texture deformation, model suspension and the like, which is inevitable for real scene three-dimensional modeling based on oblique photography technology; therefore, in combination with the actual situation, the DP-Model model repair software is used to finely and correct the defects in the initial three-dimensional real scene model, and construction machinery such as pile driving machinery and excavators is also deleted, so that the final three-dimensional real scene model is obtained, and the final three-dimensional real scene model only includes the ground and the steel casing.

[0092] Model fusion and distance measurement:

[0093] In the specific embodiment, Figure 2 is a top view of the BIM model of the impact hole filling pile and the three-dimensional real scene model of the karst area construction site; the three-dimensional real scene model obtained by the unmanned aerial vehicle oblique photography data and the BIM model of the impact hole filling pile established by MicroStation are both realized based on the wgs84 coordinate system; therefore, the BIM model and the three-dimensional real scene model are fused to obtain a fusion model; the specific steps of measuring the horizontal distance between the impact hole filling pile model and the steel casing model in the fusion model are,

[0094] Import the three-dimensional real scene model into MicroStation in FBX format, and place the three-dimensional real scene model and the BIM model in the same coordinate space in MicroStation to obtain a fusion model;

[0095] Use the measurement function in MicroStation to select the impact hole filling pile model and the steel casing model in the fusion model for distance measurement to obtain the horizontal distance between the impact hole filling pile model and the steel casing model. The deviation of the impact hole filling pile and the steel casing is as shown in Figure 3 .

[0096] Deviation monitoring:

[0097] In the specific embodiment, after monitoring the deviation distance of the impact hole filling pile in the karst area, the corresponding treatment method is selected according to the horizontal distance between the impact hole filling pile model and the steel casing model in the construction site; specifically,

[0098] If the horizontal distance between the impact hole filling pile model and the steel casing model is less than or equal to X1, the center of the impact hole filling pile reinforcement cage is aligned with the design center of the impact hole filling pile when the impact hole filling pile reinforcement cage is installed;

[0099] If the horizontal distance between the impact hole filling pile model and the steel casing model is in the range of (X1, X2], the center of the impact hole filling pile reinforcement cage is deviated to the offset direction of the steel casing when the impact hole filling pile reinforcement cage is installed, and the distance between the center of the impact hole filling pile reinforcement cage and the center of the steel casing is the difference between the offset distance of the steel casing and X1;

[0100] If the horizontal distance between the impact hole filling pile model and the steel casing model is greater than X2, the stone and clay are backfilled and the hole is re-drilled before installing the foundation reinforcement cage of the reinforced concrete pile;

[0101] Wherein, X1, X2 are preset values, X1 takes half of the difference between the diameter of the steel casing and the designed diameter of the impact-into-hole cast-in-place pile, and X2 takes the sum of X1 and the allowable value of the pile foundation deviation.

[0102] In the specific embodiment, when the allowable value of the pile foundation deviation is 5 cm, X1 and X2 are respectively 10 cm and 15 cm; and when the allowable value of the pile foundation deviation is 10 cm, X1 and X2 are respectively 10 cm and 20 cm.

[0103] The embodiment is described below with a specific application example:

[0104] Taking the Jiunan Expressway K114+600 Jiuxu Bridge as an example, the span arrangement of the bridge is 5×20 m+4×20 m+4×20 m+5×20 m. The overburden layer in the substructure is 10-20 m thick medium expansive soil, the underlying bedrock is strong weathered limestone and medium weathered limestone, and the karst development is strong. The piers of the Jiuxu Bridge are bent piers, and a reinforced concrete pile foundation is arranged under each bent pier, and the reinforced concrete pile foundation is constructed by the impact-into-hole method. The diameter of the impact-into-hole cast-in-place pile is 150 cm.

[0105] Firstly, the BIM model of the impact-into-hole cast-in-place pile of the bridge is established by using the OpenBridge Modeler and Microstation software under the Bentley platform. The diameter of the BIM model of the impact-into-hole cast-in-place pile is 170 cm, and the top elevation of the BIM model of the impact-into-hole cast-in-place pile is the top elevation of the steel casing.

[0106] Then, during the construction of the impact-into-hole cast-in-place pile, the field information data is collected periodically by using the Phantom 4RTK multi-rotor unmanned aerial vehicle carrying the RIY-D2M five-lens camera, and a phase control point is arranged every 80 m along the two sides of the highway. The flight height of the unmanned aerial vehicle is 20 m, the heading overlap is 85%, the side overlap is 85%, and 2000 photos are obtained at one time. The three-dimensional real scene model is reconstructed by using the Context Capture software under the Bentley platform, and the calculation time is about 6 hours each time. The defects in the initial three-dimensional real scene model are finely processed and corrected by using the DP-Model model modification software, and the construction machinery such as pile machinery and excavators is also deleted. Thus, the final three-dimensional real scene model is obtained, as shown in FIG. 2. Figure 2 It can be seen from FIG. 2 that the model plane error is controlled within 2 cm. Figure 2

[0107] ​Then the BIM model of the impact hole filling pile is fused with the three-dimensional real scene model, and the offset distance of the impact hole filling pile model and the steel casing model is measured. Specifically: first, the BIM model is imported into the Microstation platform in DNG format, and then the block mesh in FBX format is exported from the three-dimensional real scene model established by the Context Capture software, and then the mesh is sequentially imported into the Microstation platform in the form of a grid, thereby completing the integration of the BIM model and the three-dimensional real scene model.

[0108] In the Microstation platform, the distance between the impact hole filling pile model and the steel casing model, that is, the horizontal distance between the impact hole filling pile design plane position and the steel casing, that is, the offset position of the impact hole filling pile, is measured, as shown in Figure 3

[0109] When the horizontal distance between the impact hole filling pile model and the steel casing model is less than or equal to 5cm, it is qualified, and when installing the reinforced concrete impact hole filling pile reinforcement cage, for the convenience of construction, the center of the reinforcement cage can be aligned with the center of the steel casing;

[0110] When the horizontal distance between the impact hole filling pile model and the steel casing model is greater than 5cm and less than or equal to 10cm, since the actual diameter of the impact hole filling pile is greater than the design diameter by 20cm, when the steel casing is offset by 10cm, the center of the reinforcement cage is aligned with the design center of the pile foundation when the reinforcement cage is lowered and installed, and the minimum protection layer thickness of the impact hole filling pile can still be guaranteed to be greater than 5cm;

[0111] The center of the impact hole filling pile reinforcement cage is offset to the offset direction of the steel casing, and the distance between the center of the impact hole filling pile reinforcement cage and the center of the steel casing is the difference between the offset distance of the steel casing and X1. At this time, the distance between the center of the impact hole filling pile reinforcement cage and the design center of the impact hole filling pile can meet the pile foundation offset allowable value;

[0112] When the horizontal distance between the impact hole filling pile model and the steel casing model is greater than 15cm, although the actual diameter is greater than the design diameter by 20cm, the actual diameter of the impact hole filling pile is greater than the design diameter by 20cm, but it cannot be guaranteed that the center of the reinforcement cage with the actual diameter of the impact hole filling pile greater than the design diameter by 20cm is located in the design center of the impact hole filling pile. Therefore, it is necessary to backfill stone and clay and re-drill.

[0113] Comparative example:

[0114] ​Karst development area has complex geological conditions. Caves, grooves, fissures and other geological conditions have certain rules in macroscopic view, but are varied in microcosmic view. There are various geological conditions in overburden above bedrock. Sometimes, even the geological conditions of adjacent pile foundations of the same bridge are quite different. The pile foundation is once formed, and cannot be repeated.

[0115] To verify the effect of the embodiment, Shuikou-Chongzuo-Aidian Highway (Chongzuo-Aidian Section, total length 58.67 km) is taken as an example. There are 8 bridges in the karst geological section of Shuikou-Chongzuo-Aidian Highway (Chongzuo-Aidian Section), which are K1+343 Huipi Bridge (48 pile foundations), K4+180 Xiaqifeng Separate Viaduct (20 pile foundations), K4+605 Qufeng No.1 Bridge (48 pile foundations), K6+215 Quyang Viaduct (48 pile foundations), Tianxi Hub Interchange FK0+982.5 Ramp Bridge (112 pile foundations), Tianxi Hub Interchange GK0+551.5 Ramp Bridge (104 pile foundations), Tianxi Hub Interchange HK0+641.000 Ramp Bridge (44 pile foundations), and IK4+992 Tingliang Interchange IK4+992 Ramp Bridge (16 pile foundations), with a total of 372 pile foundations, all of which adopt impact hole-forming bored piles. The pile foundations of the above 8 bridges were started on December 19, 2020, and completed in October 2022. In June 2021, when 100 early-completed pile foundations were detected, it was found that 2 pile foundations were deviated, of which 1 was deviated by 15 cm in the bridge direction and 20 cm in the transverse direction, and the other was deviated by 10 cm in the bridge direction. In order to prevent the subsequent pile foundations from continuing to deviate, the method of the embodiment was adopted from July 2021, and by October 2022 when all the pile foundations were completed, there was no case of pile foundation deviation exceeding 5 cm.

[0116] Therefore, the embodiment successfully solves the problem of deviation monitoring of pile foundations in the karst area during the punching process. Now drones have been used in highway construction, and the embodiment will not increase hardware expenditure and has low cost, meeting the accuracy requirement.

[0117] In the deviation monitoring method of the impact hole-forming bored pile in the karst area in the embodiment, first, the BIM modeling method is used to construct a BIM model of the impact hole-forming bored pile; then a three-dimensional real scene model of the construction site is constructed by using a drone tilt photography; then the BIM model of the impact hole-forming bored pile and the three-dimensional real scene model are fused to obtain a fusion model, and the offset distance between the impact hole-forming bored pile and the steel casing is measured in the fusion model; finally, the offset distance between the impact hole-forming bored pile and the steel casing can be used to monitor the deviation degree of the impact hole-forming bored pile in the karst area. By adopting the scheme of the embodiment, the deviation degree of the position of the impact hole-forming bored pile in the karst area can be monitored at any time, and the monitoring process is convenient and does not affect the normal construction of the impact hole-forming bored pile.

[0118] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for monitoring the deviation of percussion bored piles in karst areas, characterized in that: Includes the following steps, Step 1: Using BIM modeling methods, construct a BIM model of the impact bored pile based on the diameter of the steel casing in the karst area construction site. Step 2: Construct a 3D reality model of the construction site in the karst area using oblique photography by drone; Step 3: Based on the same coordinate system, merge the BIM model and the three-dimensional real scene model to obtain a fused model, and measure the horizontal distance between the impact bored pile model and the steel casing model in the fused model; Step 4: Monitor the deviation distance of the impact-drilled cast-in-place pile in the karst area by measuring the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model; After monitoring the deviation distance of the percussion bored piles in the karst area, a corresponding treatment method is selected at the construction site based on the horizontal distance between the percussion bored pile model and the steel casing model; specifically... If the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model is less than or equal to X1, then when installing the impact-drilled cast-in-place pile reinforcement cage, the center of the impact-drilled cast-in-place pile reinforcement cage should be aligned with the design center of the impact-drilled cast-in-place pile. If the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model is within the range of (X1, X2), then when installing the impact-drilled cast-in-place pile reinforcement cage, the center of the impact-drilled cast-in-place pile reinforcement cage will be offset towards the offset direction of the steel casing. The distance between the center of the impact-drilled cast-in-place pile reinforcement cage and the center of the steel casing is the difference between the offset distance of the steel casing and X1. If the horizontal distance between the impact-drilled cast-in-place pile model and the steel casing model is greater than X2, then backfill with rubble and clay and re-drill holes before installing the foundation reinforcement cage of the reinforced concrete pile. Where X1 and X2 are preset values, X1 is half the difference between the diameter of the steel casing and the design diameter of the impact-drilled cast-in-place pile, and X2 is the sum of X1 and the allowable deviation of the pile foundation.

2. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 1, characterized in that: The specific process for constructing a BIM model of an impact-drilled cast-in-place pile is as follows: The bridge plan line is drawn using the intersection method in Openroads designer software. Draw the longitudinal profile on the bridge plane by inputting the slope, station number and vertical curve radius; Import the drawn bridge plan lines with longitudinal profiles into the OpenBridges Modeler software, and place the span lines according to the number of bridge spans and distances. Extract the custom template library files from the OpenBridges Modeler software installation directory into Miscrostation, and draw the cross section of the impact-drilled cast-in-place pile according to the diameter of the steel casing in Miscrostation; define the position of the impact-drilled cast-in-place pile in the span line by using a custom origin in the origin command to form a three-dimensional BIM template for the impact-drilled cast-in-place pile. Place the 3D BIM template of the impact-drilled cast-in-place pile in OpenBridges Modeler to obtain the BIM model of the impact-drilled cast-in-place pile.

3. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 1, characterized in that: The diameter of the impact-drilled cast-in-place pile in the BIM model is the same as the diameter of the steel casing at the construction site, and the top elevation of the impact-drilled cast-in-place pile in the BIM model is taken as the top elevation of the steel casing.

4. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 1, characterized in that: The specific process of constructing a 3D reality model of the construction site in the karst area is as follows: Semi-permanent image control points were set up around the construction site in the karst area; Based on the terrain and scope of the construction site and the drone's endurance, plan the flight route and set the flight parameters; Controlling a drone equipped with a five-lens oblique photogrammetry camera, the drone conducts field aerial surveys based on flight routes and parameters to obtain aerial survey data with imagery of ground control points. Based on aerial triangulation, a 3D scene model is generated from the aerial survey data to create a 3D real-world model of the construction site in the karst area.

5. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 4, characterized in that: The specific steps for creating a 3D scene model based on aerial triangulation and aerial survey data are as follows: Based on aerial survey data, corresponding points between adjacent images are obtained and image matching is performed to obtain parallax and depth information between adjacent images. Based on the parallax and depth information between adjacent images, combined with the position and attitude information of the images, the aerial relationship between adjacent images is calculated using photogrammetry methods. Based on the aerial relationship between adjacent images, all pixels in the images are discretized in three-dimensional space through dense image matching to obtain multiple discrete points with color information; multiple discrete points with color information in three-dimensional space form a color point cloud. Multiple discrete points in the color point cloud are connected by the TIN triangulation method to form multiple triangular patches; Multiple triangular facets are used to form a triangular mesh, which is then used as the basic model. Based on the spatial location of the colored point cloud points, the color information of the points is mapped onto the surface of the base model to obtain the initial 3D real scene model; The initial 3D reality model was refined and corrected to obtain a 3D reality model of the construction site in the karst area.

6. The method for monitoring the deviation of impact-drilled cast-in-place piles in karst areas according to claim 4, characterized in that: In the flight parameters, the forward overlap is not less than 75%, the lateral overlap is not less than 60%, the UAV adopts close-up photogrammetry, and the flight altitude is 15m to 40m.

7. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 2, characterized in that: Based on the same coordinate system, the BIM model and the 3D reality model are fused to obtain a fused model. The specific steps for measuring the horizontal distance between the impact-drilled pile model and the steel casing model in the fused model are as follows: The 3D reality model of the karst area construction site is imported into MicroStation in FBX format, and the 3D reality model of the karst area construction site and the BIM model of the impact bored pile are placed in the same coordinate space of MicroStation to obtain the fused model. Using the measurement function in MicroStation, the impact-drilled pile model and the steel casing model in the fusion model were selected to measure the distance, and the horizontal distance between the impact-drilled pile model and the steel casing model was obtained.

8. The method for monitoring the deviation of percussion bored piles in karst areas according to claim 1, characterized in that: When the allowable deviation of the pile foundation is 5cm, X1 and X2 are taken as 10cm and 15cm respectively; when the allowable deviation of the pile foundation is 10cm, X1 and X2 are taken as 10cm and 20cm respectively.

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