Research On Simultaneous Monitoring Of Ground Subsidence And Bridge Deformation By 3D Laser Scanning

Using three-dimensional laser scanning technology to synchronously scan the surface of the mining area and the bridges located on the surface,it can collect massive laser point cloud data of the surface and the bridge,and the multi-phase scanning data can be compared and analyzed after coordinate conversion.On the one hand,it can obtain the surface deformation,but also The overall posture deformation and structural minor deformation of the bridge can be obtained,the impact of ground subsidence on the deformation of the bridge located in the subsidence area can be studied,the displacement and deformation response of the bridge body after the ground deformation is transmitted to the bridge can be analyzed,and the damage of the bridge structure can be evaluated.Early warning is given in time when the bridge is in danger to avoid accidents.In this paper,the main research contents of the deformation monitoring of the ground surface in the subsidence area and the bridge located on the ground surface are as follows:(1)Research on 3D laser scanning technology for deformation monitoring project plan design.Due to the different conditions of the site environment and monitoring range,the plan design is also different.This paper proposes a registration plan combining rear-view orientation and target,which is used in large-scale deformation monitoring,Which can control the overall geodetic coordinates while taking into account the registration error between the two stations to the greatest extent,providing accuracy guarantee for the deformation monitoring project.(2)Aiming at the problem of ground point cloud extraction,an adaptive grid method is proposed on the basis of the traditional division rule square grid taking the lowest point.In the plane area,the grid spacing is large and the terrain slope is large in complex terrain areas.Properly encrypt the square grid,and initially improve the accuracy of ground seed points.Use the initial ground points obtained by the adaptive grid method to construct a TIN network,and then use the progressive triangulation method to separate ground points and non-ground points,so that the extracted ground points achieve the desired effect;(3)Aiming at the problem of ground point cloud extraction,an adaptive grid method is proposed based on the lowest point of the traditional grid division rule.The grid spacing is large in the plane area and the complex terrain area with large terrain slope is appropriately encrypted.The square grid initially improves the accuracy of ground seed points.The initial ground points obtained by the adaptive grid method are used to construct a TIN network,and then the progressive triangulation method is used to separate ground points and non-ground points,so that the extracted ground points can achieve the desired effect.(4)Collect the point cloud data of the third phase of the railway bridge in the subsidence-affected area during the mining process.Based on the first phase,using the ICP multiple iterative algorithm,the latter two phases are compared with the first phase of the point cloud attitude.The transformed rotation matrix is used to describe the displacement and tilt of the overall posture of the bridge body during the mining process of the working face,and to verify the results from characteristic points,characteristic lines,etc.at the same time,the bridge body is modeled and 3D/2D deviation analysis is used Analyze the micro-deformation of the bridge and identify the cracks of the bridge based on the edge detection method.(5)According to the surface deformation trend,combined with the overall and local deformation of the bridge,the coordinated deformation of the two is analyzed,mainly including synchronous subsidence and tilt analysis and horizontal movement analysis.This paper has 60 pictures,17 tables,and 110 references.