Application And Research Of Non-fixed Control Points Photogrammetry In The Tunnel Monitoring Measurement

The current construction of tunnel and other underground projects are more and more widespread in the basic construction such as in the rail transportation, water conservancy and national defense construction.So the tunnel and underground engineering monitoring work is very necessary.The tunnel monitoring measurement is the important basis for testing stability of tunnel construction and has a important guiding significance to the tunnel construction process each link.With the development of photogrammetry and digital camera technology, non-metric digital camera has been widely used in close-range photogrammetry, and prompts the huge development potential of the digital close-range photogrammetry in the field of civil engineering safety monitoring.In order to improve the methods of tunnel construction monitoring measurement, this paper researches the application of digital photogrammetry technology,adopts the non-metric digital camera and the method of non-fixed control points, promots the application of photogrammetry in tunnel construction monitoring measurement.At the same time, the photogrammetry tunnel monitoring system is developed on the basis of non-fixed control points.Through the methods of field investigation,monitoring and indoor simulation, A series of specific studies are carried out to the application of non-fixed control points photogrametry in the tunnel monitoring measurement. The main research contents are the following aspects:(1) A method of non-fixed control points photogrammetry is adopted according to the features of tunnel monitoring measurement and the particularity of construction environment. The method has been realized in the application of the tunnel monitoring measurement through the field test.(2) A complete close-range photogrammetry tunnel monitoring system has been developed. It can achieve or meet the accuracy requirement of tunnel monitoring measurement and has a great application popularization value.(3) The method of double image photogrammetry is explored in the application of the tunnel section contour measurement and the feasibility of the method is verified through the field test.(4) A high accuracy indoor three dimensional control field is set up according to the actual situation of indoor control field. The ordinary digital camera calibration is carried out through the indoor control field.The camera calibration parameters are calculated and the accuracy evaluation has been given.The results have a high reliability.(5) A tunnel monitoring measurement simulation experiment is carried out through the indoor control field. The experiment results show that, the method of non-fixed control points photogrammetry can meet the accuracy requirement of tunnel monitoring measurement in indoor control field ideal environment.(6) The method of analytical plumb line is researched to calculate the relative elevation between the measuring points.It adopts relative control by using vertical without relying on the fixed points of control. The experiment results show that, the accuracy can meet the accuracy requirements of the experiment.