Subway Tunnel Laser Scanning Detection Trolley Research And Development

With the rapid development of urban rail transit,there are a large number of people across the country choose subway travel,subway tunnel safety problems have become more severe.Tunnel convergence deformation monitoring is also an important part of metro tunnel deformation monitoring.The traditional measurement of the ruler meter is less efficient and the field work is large.The measurement of the tunnel section using the measurement robot is convenient,but the cost is high,and only the coordinates of the part of the section can be measured.Time is long and the measurement accuracy is susceptible to environmental factors.The use of terrestrial 3D laser scanning technology to scan the subway tunnel can only improve the efficiency to a certain extent,although the measurement accuracy is high,but the data acquisition repetition rate is too high,the data processing process is also more cumbersome.In view of the above shortcomings,this paper proposed three-dimensional laser scanner and track car together,and equipped with odometer,distance sensor,tilt sensor and built-in computer,with the use of scanning targets,composed of laser scanning detection car,using line scan mode,The track trolley along the rail in the tunnel will be able to scan the tunnel wall at the same time,greatly improving the efficiency of field measurement.The scanner scans the tunnel at the same time as the odometer,distance sensor and tilt sensor real-time recording laser scanning to detect the car's forward distance,the center of the car and the center line of the line and the trolley's roll angle and pitch angle.When the data is processed,the position and azimuth of the car are calculated according to the mileage meter data and the tunneling design document.According to the relative position relation between the scanner and the track car and the position and attitude of the car,the scanning point is initially calculated in the measurement coordinate system,The scanning time and coordinates of the center point of the scanning target are extracted from the point cloud,and the odometer is bound.After the processing is completed,the corresponding points can be extracted directly according to the mileage,and the RANSAC algorithm is used to extract the noise points and the debris points,and the cross-section curve is fitted to calculate the convergence value.This paper mainly studies the measurement principle of laser scanning detection car,and the collection,storage and processing methods of measurement data.Aiming at the line scanning mode,it is proposed to use the odometer and tunnel design file to locate the laser scanning detection trolley.The RANSAC algorithm is used to proceed to the tunnel point cloud by using the scanning target and CPIII point coordinates.Noise and fitting methods,and finally calculate the convergence value of subway tunnels.In order to verify the feasibility of this deformation monitoring method,this paper carries out the scanning experiment in Wuhan subway tunnel,and the collected data are processed and calculated.The results show that the measurement method used in laser scanning detection car can meet the requirements of deformation monitoring of subway tunnel.Contrast with the traditional method of tunnel convergence measurement and ground 3D laser scanning technology,the field of data collection efficiency is higher.