Study Of Tunnel Deformaiton Monitoirng Based On Digital Close-range Photogrammetry

With the continuous development of economic construction, our countryinvestment in infrastructure is constantly increasing, tunnel and undergroundengineering number is also growing. However, accidents increased gradually in tunnelconstruction engineering. With the New Austrian Tunneling Method to introducedomestic, people began to pay attention to the monitoring measurements duringconstruction of the tunnel and underground engineering. Monitoring measurementmethods have using Total Station and convergence device, but both methods have theproblems of needing a job long time and interfering with on-site construction.In recent years, with the continuous development of digital cameras, digitalclose-range photogrammetry which is non-contact measurement methods began to bereceived wide attention in the field of safety monitoring of the tunnel project. This paperfocuses on engineering practice, the characteristics of the underground tunnel project,developed a set of tunnel deformation monitoring system, based on digital close rangephotogrammetry and. with the system we can achieve non-contact measurement andwith the deformation monitoring data, we can analysis of the stability of the tunnel,Compared with traditional methods, this method has the advantages：the short time offield operate, the large amount of observational information, the higher degree ofautomation, simple operation, operational safety. The main content of this study includethe following aspects:①The tunnel in construction process light inadequacy and dust heavy, how toobtain ideal photos through effective means in this case, and, how to get photos forprocessing.②Introduce the basic theory of close-range photogrammetry and commonly usedanalytical methods, the use of non-metric cameras tunnel deformation measurementmethods and specific steps. Understand the method of camera calibration and use theCamera Calibration Toolbox for Matlab to calibrate the camera.③Processing the collection digital photos, and compiling program which canmeasure the pixel coordinates on this basis.④According to the basic principle of relative orientation, we can use P-Halgorithm to put forward the specific solution algorithm of model coordinate.⑤Discusses the basic theory of free network adjustment and the application of photogrammetry, study how to combine the free network adjustment methods tocalculate the object space coordinates of the measuring point in tunnel constructionwhere is no fixed party control of the point. And base on the theory of free networkadjustment to achieve the unity of the observation coordinates benchmark in thedifferent periods.⑥Prepare procedures in order to achieve which photogrammetry can be used inthe tunnel deformation monitoring. Introduce the basic form and function and conduct afield trial in tunnel of Zhong Liangshan, we also use total station to test the accuracy.