Tunnel axis fitting method and application thereof in calculation of over-excavation and under-excavation amount
A tunnel and axis technology, applied to the calculation of excess and underexcavation, in the field of tunnel axis fitting, can solve the problems of time-consuming and laborious, the algorithm can not accurately fit the axis position, etc., to achieve low labor costs and improve data effectiveness performance, reducing the amount of calculation and the effect of calculation difficulty
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Embodiment 1
[0066] This embodiment discloses a tunnel axis fitting method based on laser point cloud data, including the following steps:
[0067] 1. The preprocessing step of the tunnel point cloud data, the tunnel point cloud data is the three-dimensional point cloud data obtained after scanning the excavated tunnel by the ground three-dimensional laser scanning system. The preprocessing steps include in turn: establishment of data topology, data filtering, data compression, data splicing and feature fitting steps.
[0068] 2. A step of fitting the tunnel axis based on the preprocessing result. The tunnel axis fitting step includes: a step of evaluating the surface normal vector of the initial pavement part in the preprocessing result, and a subsequent tunnel axis fitting step. Among them, the evaluation of the surface normal vector adopts the moving least square method (Moving Least Square, MLS) to evaluate the surface normal vector of the initial paving part, so as to correct the sur...
Embodiment 2
[0070] This embodiment discloses a tunnel axis fitting method based on laser point cloud data, including the following steps:
[0071] 1. Preprocessing steps of tunnel point cloud data
[0072] The tunnel point cloud data is the 3D point cloud data obtained by scanning the excavated tunnel through the ground 3D laser scanning system. Such as figure 1 Shown is a set of tunnel 3D point cloud data models. Before the axis fitting, the tunnel point cloud data needs to be preprocessed, and the preprocessing process includes the following steps.
[0073] A. Data topology establishment
[0074] Before calculating the point cloud data, it is necessary to establish a topology for the point cloud data.
[0075] The adjacent points of any data point in the point cloud are closely related to the properties of the point, and the K points adjacent to the data point are called K nearest neighbors. The point cloud data obtained by a 3D laser scanner is generally an unordered point cloud. ...
Embodiment 3
[0125] On the basis of fitting the initial plane axis, this embodiment discloses an analysis method for over- and under-excavation in tunnel construction: on the basis of fitting the tunnel axis vector, use the rotation matrix to rotate the point cloud data, and make the vector through the rotation coincides with the positive direction of the z-axis. The three rotation matrices around the x-axis, y-axis, and z-axis are shown in formulas (5.1), (5.2) and (5.3):
[0126]
[0127]
[0128]
[0129] Where: R x (ψ), R z (θ) are the clockwise rotation ψ around the x, y, and z axes, Rotation matrix for angle θ.
[0130] In order to more intuitively observe the deviation between the excavation situation and the design plan, after fitting the axis direction, project the initial cladding part onto a two-dimensional plane from the cross-sectional direction for observation. The RANSAC algorithm is used to fit the center of the circle projected on the two-dimensional plane ...
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