Research I

Introduction

The new line from Wendlingen to Ulm, part of the new trans-European Main Line from Paris to Budapest, is presently under construction. This new line is designed for running speeds of up to 250 km/h and has a total length of approximately 60 km with about 50 % running through tunnel constructions. One significant project section on the new line is the PFA 2.3 Alb high plain (Albhochfläche), which ranges from km 53+811 near Hohenstadt over Merklingen and Temmenhausen to km 75+250 near Dornstadt (Fig. 1, Fig. 2). The approximately 21.4 km long Alb high plain is mainly characterized by open-air line and smaller tunnels. The excavation bottom level on the Alb high plain is predominantly situated in limestones of the Upper Jurassic, which are primarily affected by karstification and can be classified as slightly to heavily karstified. In order to determine the dimension of karstification of the Alb high plain, comprehensive, independent and complementary indirect geophysical investigations including microgravimetric and seismic methods were previously conducted at the excavation bottom level. In the course of the present research study, 2D electrical resistivity tomography (ERT) measurements were performed in addition to the standard investigation program to explore geological defective karst voids and other karstic features including (i) their geometry (size, shape, spatial distribution) and (ii) their type of filling (non, partially or almost completely filled with soil material and/or water).