CN113808093A - Tunnel primary support shotcrete thickness detection method based on 3D laser scanner - Google Patents
Tunnel primary support shotcrete thickness detection method based on 3D laser scanner Download PDFInfo
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Abstract
The invention discloses a method for detecting the thickness of primary tunnel shotcrete based on a 3D laser scanner, which comprises the following steps: at least three chessboard target plates are arranged on the tunnel surrounding rock behind the area to be measured, and the central points of the chessboard target plates are connected to form a plane; before and after the primary support concrete of the tunnel is sprayed, measuring an area to be measured by using a 3D laser scanner respectively to obtain first point cloud data and second point cloud data; splicing the first point cloud data and the second point cloud data, and then extracting third point cloud data of the jetting area from the point cloud data generated by splicing; the positioning reference of the spliced point cloud data is a plane; and processing the third point cloud data by using the standard point cloud data to obtain the thickness of the sprayed concrete. The 3D laser scanner realizes carrying out automated inspection to tunnel preliminary bracing shotcrete, combines the design requirement to contrast shotcrete volume, can provide guiding suggestion to follow-up construction according to the testing result, has realized intellectuality.
Description
Technical Field
The invention belongs to the technical field of tunnel shotcrete thickness detection, and particularly relates to a tunnel primary support shotcrete thickness detection method based on a 3D laser scanner.
Background
At present, a large amount of spray anchor supporting methods are used for primary tunnel supporting in China, and spray anchor supporting has the advantages of no need of templates, high strength, good cohesive force, low cost and the like in the primary supporting, but the sprayed concrete has the phenomenon of excess or deficiency due to the lack of the limitation of the templates. In order to improve the construction quality and meet the design requirements, higher requirements are required to be provided for the precise construction of the primary support of the section of the tunnel, so that the detection of the spraying and mixing thickness and the volume and the guidance of the construction according to the detection result are particularly critical. In recent years, with the gradual maturity of the 3D laser scanning technology, a solid foundation is laid for developing a detection method for parameters such as thickness and volume of tunnel primary support shotcrete based on a 3D scanner.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for detecting the thickness of primary tunnel shotcrete based on a 3D laser scanner.
The technical problem to be solved by the invention is realized by the following technical scheme:
a tunnel primary support shotcrete thickness detection method based on a 3D laser scanner comprises the following steps:
step (1): at least three chessboard target plates are arranged on the tunnel surrounding rock behind the area to be measured, and the central points of the chessboard target plates are connected to form a plane;
step (2): before and after the primary support concrete of the tunnel is sprayed, measuring an area to be measured by using a 3D laser scanner respectively to obtain first point cloud data and second point cloud data;
and (3): splicing the first point cloud data and the second point cloud data, and then extracting third point cloud data of the injection area from the point cloud data generated by splicing; wherein, the positioning reference for splicing the point cloud data is the plane;
and (4): processing the third point cloud data by using standard point cloud data to obtain the thickness of the sprayed concrete; the standard point cloud data is generated according to a design drawing.
Further, the step (4) includes:
step (4.1): performing coordinate rotation and contour fitting according to the third point cloud data and the standard point cloud data to obtain fourth point cloud data;
step (4.2): and calculating and obtaining the thickness of the sprayed concrete according to the fourth point cloud data.
Further, in the step (4.1), the coordinate rotation and the contour fitting of the third point cloud data and the standard point cloud data are performed by using an ICP algorithm and a least square method.
Further, in the step (4.2), the fourth point cloud data is calculated by using an arc-shaped cross section cutting method, so that the thickness of the sprayed concrete is obtained.
The invention has the beneficial effects that:
1. by means of a 3D laser scanning technology, the free setting of a station can be realized, and the scanning detection of the sprayed concrete can be carried out without contact and damage so as to obtain point cloud data of the sprayed concrete; by analyzing and processing the point cloud data, the detection precision can be greatly improved, the detection speed is shortened, the detection cost is reduced, the detection method and operation are quicker and more efficient, and the spraying and mixing thickness detection under various environments can be met;
2. realize carrying out automated inspection to tunnel preliminary bracing shotcrete through 3D laser scanner, combine the design requirement to contrast shotcrete volume, can provide guiding suggestion to follow-up construction according to the testing result, realized intellectuality, and do not influence the normal operation in tunnel.
Drawings
FIG. 1 is a schematic flow diagram of the present invention;
FIG. 2 is a schematic structural view of a chessboard target plate;
FIG. 3 is a schematic diagram of first point cloud data;
FIG. 4 is a schematic diagram of second point cloud data;
FIG. 5 is a schematic illustration of third point cloud data;
FIG. 6 is a diagram illustrating the result of cloud data processing at a third point;
fig. 7 is a schematic diagram of the coordinate transformation and contour fitting effects of the third point cloud data and the standard point cloud data.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.
The embodiment of the invention provides a tunnel surrounding rock blasting earth volume detection method based on a 3D laser scanner, please refer to fig. 1, which specifically comprises the following steps:
step (1): at least three chessboard target plates are arranged on the tunnel surrounding rock behind the area to be measured, and the central points of the chessboard target plates are connected to form a plane.
The chessboard target plates are shown in fig. 2, in practical use, the number of the chessboard target plates is at least three, the centers of the at least three chessboard target plates are not collinear, three central points are connected to form a plane which is mainly used for positioning, and the positions of the chessboard target plates used for positioning before and after measurement should be kept unchanged. Software matched with the 3D laser scanner can identify the central point of the chessboard target plate, and if the software can identify three central points which are not collinear, splicing of the measured point cloud data before and after explosion can be realized.
Step (2): before and after the primary support concrete of the tunnel is sprayed, measuring an area to be measured by using a 3D laser scanner respectively to obtain first point cloud data and second point cloud data; as shown in fig. 3 and 4.
The first point cloud data and the second point cloud data in the embodiment of the invention refer to three-dimensional coordinates of pixels of a primary support section obtained by scanning, are part of information of measurement data of a 3D laser scanner, and can be directly extracted.
If the first point cloud data and the second point cloud data obtained by the 3D laser scanner are too large, point cloud dilution processing can be performed by adopting a conventional algorithm under the condition that the requirement of measurement accuracy is met, so that the algorithm efficiency of subsequent registration fitting is improved.
Before the 3D laser scanner is measured, tripod leveling and instrument measuring range reasonable adjustment need be carried out, thereby improving measuring efficiency.
This 3D laser scanner website sets up and can freely select, need not instrument cooperations such as total powerstation, convenient operation, and it can independently establish the station, and the station need not the coincidence around.
And (3): splicing the first point cloud data and the second point cloud data, and then extracting third point cloud data of the injection area from the point cloud data generated by splicing; and the positioning reference for splicing the point cloud data is the plane.
Reading the first point cloud data and the second point cloud data, and splicing the first point cloud data and the second point cloud data by using the three-dimensional outline of the plane formed by the chessboard target plate, i.e. the three-dimensional coordinates of the plane formed by the chessboard target plate in the first point cloud data are superposed with the three-dimensional coordinates of the plane formed by the chessboard target plate in the second point cloud data; and then extracting third point cloud data of the spraying area from the overlapped point cloud data, as shown in fig. 5. If the amount of the third point cloud data is too large, further processing can be performed, and redundant useless information can be taken out, as shown in fig. 6.
And (4): processing the third point cloud data by using standard point cloud data to obtain the thickness of the sprayed concrete; the standard point cloud data is generated according to a design drawing.
Further, the step (4) may include the steps of:
step (4.1): and performing coordinate rotation and contour fitting according to the third point cloud data and the standard point cloud data, and obtaining fourth point cloud data as shown in fig. 7.
Specifically, the coordinate rotation and the contour fitting of the third point cloud data and the standard point cloud data are performed by using an ICP algorithm and a least square method.
And the third point cloud data is transformed to a coordinate system which is the same as the standard point cloud data by solving a rotational translation matrix between the two point cloud data, so that subsequent calculation is facilitated, and the least square method is used for calculating errors in the fitting process, so that the contour fitting result is more accurate.
Step (4.2): and calculating and obtaining the thickness of the sprayed concrete according to the fourth point cloud data.
Specifically, the fourth point cloud data is calculated by using an arc-shaped section cutting method, and the thickness of the sprayed concrete is obtained.
The arc-shaped section cutting method is characterized in that the arch-shaped included angle of sprayed concrete is cut, the arch-shaped radius after the sprayed concrete is subtracted from the arch-shaped radius to obtain the thickness of the sprayed concrete in each cutting surface, and the average value of the thicknesses of the cutting surfaces is obtained to obtain the thickness of the sprayed concrete.
The area of the sprayed concrete is obtained by integrating the thickness of the sprayed concrete along the arc length, and then the area is multiplied by the width of the sprayed concrete, so that the volume of the sprayed concrete is obtained.
Comparing the thickness of the sprayed concrete obtained by calculation with the designed thickness value, and judging whether the sprayed concrete is excessive or insufficient, so that the blasting quality can be evaluated; meanwhile, if the thickness value of each cutting surface is compared, if the thickness value exceeds the designed value, the position of the cutting surface is subjected to blasting and overexcavation; if the thickness value is smaller than the design value, blasting underexcavation of the position of the cutting surface is indicated, and therefore an instructive suggestion can be provided for next blasting.
Meanwhile, the spraying quality can be seen from the profile of the sprayed concrete scanned by the 3D laser scanner. In addition, the effective utilization rate of the concrete can be calculated according to the volume of the sprayed concrete.
The detection method is practically applied to Qiantangjiang river stations in Qingdao subway No. 6 line 05 work area engineering, and the detection results of the thickness and the volume of sprayed concrete are obtained by measuring with a 3D laser scanner and comparing point cloud data before and after the sprayed concrete by using a mathematical algorithm, so as to guide the construction of the next stage; the detection method has the advantages of high working reliability, high measurement speed, good use effect and convenience in popularization and use.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (4)
1. The tunnel primary support shotcrete thickness detection method based on the 3D laser scanner is characterized by comprising the following steps of:
step (1): at least three chessboard target plates are arranged on the tunnel surrounding rock behind the area to be measured, and the central points of the chessboard target plates are connected to form a plane;
step (2): before and after the primary support concrete of the tunnel is sprayed, measuring an area to be measured by using a 3D laser scanner respectively to obtain first point cloud data and second point cloud data;
and (3): splicing the first point cloud data and the second point cloud data, and then extracting third point cloud data of the injection area from the point cloud data generated by splicing; wherein, the positioning reference for splicing the point cloud data is the plane;
and (4): processing the third point cloud data by using standard point cloud data to obtain the thickness of the sprayed concrete; the standard point cloud data is generated according to a design drawing.
2. The method for detecting the thickness of the primary shotcrete in the tunnel based on the 3D laser scanner as claimed in claim 1, wherein the step (4) comprises:
step (4.1): performing coordinate rotation and contour fitting according to the third point cloud data and the standard point cloud data to obtain fourth point cloud data;
step (4.2): and calculating and obtaining the thickness of the sprayed concrete according to the fourth point cloud data.
3. The method for detecting the blasting earthwork of the tunnel surrounding rock based on the 3D laser scanner as claimed in claim 2, wherein in the step (4.1), the coordinate rotation and the contour fitting of the third point cloud data and the standard point cloud data are performed by using an ICP algorithm and a least square method.
4. The method for detecting the blasting earthwork of the tunnel surrounding rock based on the 3D laser scanner as claimed in claim 2, wherein in the step (4.2), the fourth point cloud data is calculated by an arc-shaped cross section cutting method to obtain the thickness of the shotcrete.
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| CN116255904A (en) * | 2023-02-27 | 2023-06-13 | 北京城建设计发展集团股份有限公司 | Automatic measuring method and system for concrete volume of tunnel hole wall spraying by mine method |
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