Abstract

In this paper, the authors have studied and investigated the theory and experimental evidences in order to evaluate the deviation of the local geodetic coordinates of the control points due to the influence of the elevation difference and the influence of the plumb deviation within a scope of 10km. The authors have also investigated the deformation characteristics of the local geodetic coordinates and the local UTM coordinates according to dimensions of the examined area and the elevation difference of control points, including the mountainous regions with great elevation difference. From the obtained results, the authors have proposed the use of the local geodetic coordinates system for determining the reference frame applicable to tunnels excavated from two opposite sides (also called break-through excavation) in the plain and mountainous areas as well.