GEODETIC WORKS IN TUNNEL CONSTRUCTION AND DEFORMATIONS OF TUNNEL

Abstract

In this study, tunnel subject that is a one of the main items of transportation system and deformations of tunnel with geodetic works for tunnels are examined. Because of the better education, industry and trade opportunities in cities, rapid and intense migration wave, unplanned urbanization, rapid increase in population, reduction of lands and increase in construction, bulky structure of public institutions etc., our cities are exposed to a heavy traffic. Because marine, air and rail transport is neglected, the entire load of transportation is on the highway transportation system in Turkey. Because of easy crossing of challenging topography, no disruption of physical environment, shortening of distances, easy struggle with climate and environmental conditions, developments in cartography and technology, tunnels become an indispensable element for different purposes (water and wastewater lines, storage, energy, ventilation etc.) especially for transportation. The main errors encountered in tunnels are plump deflection, refraction error, breakthrough error with physical problems in tunnels have been explained. One of the most implemented methods moreover the classical tunnelling method ''New Austrian Tunnelling Method (NATM) has been explained. Furthermore, information about TBM (EPBM) machines and their excavation and working systems of modern tunnelling method has been given. In the present study, deformation concept which has a vital importance for major engineering projects especially for tunnels is investigated. In order to get the deformation measurements, LIDAR, terrestrial laser scanning, close distance photogrammetry, geodetic measurements, laser interferometry method and geotechnical methods are employed. For monitoring of tunnel deformations, periodical geodetic measurements, balancing them, supporting the geodetic measurements by other measurement methods, analysis of the results have been implemented and taking necessary precautions issues have been emphasized. The most important issue for tunnel and highway projects is establishment of geodetic networks and application of the projects based on these networks. Information is given about the geodetic network points (horizontal and vertical control points) produced by GNSS and leveling methods for the Honaz Tunnel ongoing construction in Denizli-Honaz and connection roads with additional highway routes. Additionally, deformation measurements are accomplished at a specific sections of Honaz Tunnel. The deformation analysis using with displacement vector method were performed and the obtained data (calculations, figures, charts and graphics) were interpreted. Over the period from the preparation of tunnel and highway projects to the completion of construction, the importance of geodetic studies with geomatic engineering was emphasized and various proposals on the topic were presented