Abstract (eng)
This master thesis deals with the engineering geological mapping and rock stability analysis in/at the tunnel St. Michael - Wachau-Bahn/Lower Austria. The tunnel is part of the Donauuferbahn, which reaches from Mauthausen to Krems an der Donau. In the course of the construction work, Venus von Willendorf, Austria's best-known find from the younger Paleolithic period, was found in 1908. The section of the line between Krems an der Donau and Emmersdorf an der Donau is called the “Wachaubahn”. The route begins in Krems on the Danube and ends in Mauthausen. The tunnel is located at Kilometer 17,201. At the western and at the eastern entrance of the tunnel there are embankments that were cut at the Danube federal road.
In the study area, which extends over the entire area, there are Paragneiss alternations and Schists. In order to get a first impression of the natural ground, inspections were carried out initially and the crown and the walls of the tunnel were thoroughly examined. During these visits, initial estimates of rock- and rock mass strength, weathering, fracturing and bonding strength could be made. In the course of this, areas with danger potential due to open and weathered fissures and sagging ridge vaults were identified and recorded.
To determine the rock parameters required for the stability analysis, geometrical parting surface images were carried out using the scanline method relating to the length of the tunnel. Using a geological compass, the dip and the dip direction of the joints could be recorded. With the help of a Schmidt-Hammer, the rock compressive strength of the existing rock types was determined in sections.
In order to be able to do the stability analysis, the map of the tunnel and the area was first shown and all of the data that were carried out by the study area and implemented on the map. Then the tunnel was divided into 3 different units and calculation profiles. Rock mass classification methods such as RQD, GSI and Q-System were used for this. The subsequent computer analysis of the tunnel was realised with two finite element programs, Examine 2D, RS2, EX3, RS3, UnWedge and Swedge. The stability analysis of the rock slope was carried out according to the result of the kinematic analysis of the slope instability, with Dips, RocPlane and Swedge software.
In addition, the probability distribution of the separating surface distances was analysed in the MATLAB. The statistical analysis of the discontinuity properties is based on this analysis method, including the following: dip direction/ dip, spacing, discontinuous of fractures and frequency, size, length and shape of the discontinuities.
Keywords: Stability analysis, engineering geological mapping, Rock mass classification, kinematic analysis, statistical analysis, discontinuity properties, 2D FE analysis, 3D Methode moldeling.