SBTn basic surveying for tunnelling

Major tunnel projects like the new Semmering Base Tunnel require intensive design work long before construction can start. Design work is based on basic surveying, which is subject to particular requirements on major projects of engineering geodesy. The most important basis is a homogeneous and stress-free basic control network for position and height, represented by suitable stabilised points. The conception and implementation of this basic control network poses stringent requirements for the surveyor. On the one hand, great precision and reliability are required, and on the other hand design requirements have to be considered along with the numerous geodetic and geophysical considerations. The most challenging work, which has to be undertaken above ground for the later tunnelling works, is described in detail in this article