Tunnelling is one of the most difficult fields of ground and rock engineering. However, the many technological advances in modern tunnelling have not been accompanied by a rational understanding of the underlying mechanical problems. Thus, tunnelling remains rather an art than an engineering science and is mainly based on the intuition of few specialists. In more and more cases the lack of rational approach is tried to be overcome by the extensive use of finite element methods in tunnelling. In many cases, however, this powerful tool is not appropriately used and many applications to tunnelling are not convincing. Very often, the assumed loads and material properties are felt to be widely arbitrary. In most cases the input parameters are trimmed to yield intuitively acceptable results.
Therefore, there is a need for a better theoretical understanding of the relevant mechanical processes as this is aimed by the proposed course. A simple though sound introduction of the pertinent boundary value problems will be accompanied by an exposition of the basic characteristic of the mechanical behaviour of soil and rock and their interaction with ground water. Subsequently analytical and numerical solution methods will be presented. A permanent reference to practical problems and case studies will be seeked.
One of the goals of the course will be to introduce mechanical models that explain the measured stresses and deformations. One of the main shortcomings of contemporary tunnelling is the failure to evaluate the measured data on the basis of a rational mechanical analysis. Thus, the application of the observational method, which is claimed to be a basic procedure in tunnelling, is virtually incomplete and more or less useless, as the engineers in the practice fail to interprete the obtained data.
Of particular importance will be the analysis of some tunnel collapses based on the consideration of simplified models for stress and strain distributions.