Deformation Monitoring Of Forest Roadside Slopes And Bridges Via Terrestrial Laser Scanning Technique

The normal operation of the forest area cannot be separated from the construction of infrastructure such as road slopes and bridges.The timely monitoring of road slopes and bridges in forest areas is an important part of its normal operation.The monitoring environment in the forest area is complex,and the continuous development of relevant advanced monitoring technologies has gradually promoted the research and application of safety monitoring of forest roads and bridges.With the continuous development of terrestrial laser scanning(TLS)technology,TLS has been widely used in many fields.TLS technology is applied to the monitoring of road slopes and bridges in forest areas.It can timely,effectively and quickly monitor road slopes with landslide hazards,obtain point cloud information on bridge surfaces,and then judge the safety of bridges,avoiding or reducing forest areas.Damage caused by landslides and bridge damage.Based on the analysis and study of related theories,this paper applies TLS technology to road slope and bridge deformation monitoring research in the forest area,and selects the common arch bridges,girder bridges,road slopes and rock slopes as research Object.Due to the lack of reliable design data for ancient stone arch bridges in some forest areas,it is difficult to efficiently identify its detailed overall geometric features and deformation analysis.For the difficulties in beam bridge deflection monitoring,it is difficult for discrete monitoring points to describe the overall deformation of the bridge;roadside slope monitoring in forest areas The environment is complex,it is difficult for the discrete monitoring points to describe the overall surface displacement of the slope,and it is impossible to obtain a comprehensive and accurate problem of the geometry and texture information of the rock face of the steep rock mass.Field collection of relevant data,construction of the corresponding slope DEM and bridge three-dimensional model,and the deformation safety evaluation of the slope deformation trend and the construction of the bridge model.The main research contents of this paper and the research results obtained are as follows:(1)Analyze and study the method of acquiring TLS data,study the preprocessing method of point cloud data and the overall least-squares plane fitting method.(2)Analyze and study the surface reconstruction algorithm.The surface reconstruction method of Delaunay triangulation based on Voronoi diagram and Delaunay triangulation is studied.The algorithm steps are given.The surface reconstruction algorithm based on B-spline basis function and NURBS inhomogeneous parameters is studied,and the NURBS surface reconstruction method and the algorithm flow is given.(3)The TLS technique was used to model and analyze the arch bridges in the forest area.The TLS technique was used to collect the whole three-dimensional point cloud data of the arch bridge.Then the multi-viewpoint cloud data was registered,denoised,and reduced using the stitching method based on geometric features.The NURBS algorithm is used to extract,fit and reconstruct the stone arch members,and a three-dimensional solid model of the stone arch bridge is constructed.The stone arch bridge is sized and counted,and the whole point least square method is used to fit the stone arch point cloud and the arch bottom is compared.Analysis,superposition analysis and symmetry analysis have analyzed and summarized the deformation of stone arches.Based on the analysis of deflection and deformation of two phases of TLS bridge point cloud,according to the specific characteristics of the measured bridge beam,the whole point least square method is used to fit the surface point cloud,and the outer contour of the beam point cloud is extracted based on the RANSAC algorithm.The axis fitting calculation,starting with the force characteristics of the girder bridge and its deformation characteristics,analyzes the deflection of the beam under two stages of static loading,and verifies the feasibility of the technology in the deflection measurement of bridges,which is the detection of bridge deflection.Provide a new idea and method.(4)Using TLS technology to monitor and analyze the slope.The cloud data of the slopes in the two phases of the road slope in the study area were collected,and the original point cloud data was preprocessed.The slope DEM was constructed based on the NURBS surface reconstruction method.The two-phase slope monitoring data model was accurately calibrated at the target point.The superposition comparison was performed.Four sections were taken at equal intervals on the overlapping surfaces.The intercepted sections were linearly fitted and the deformation variables were compared to obtain the displacement state of the slope surface.TLS is used to obtain the surface point cloud information of high-steep rock slopes.The fitting plane tool generated by the Delaunay triangulation method is used to simulate the rock mass structure surface.The texture of the rock body surface is obtained,and the structural plane of the rock mass is analyzed and calculated.And rock fractures and other geometric parameters.