Week 2 Tunnelling & TBM Course: Geological and Geotechnical Aspects of Tunnelling

Week 2 (27th Jan '14 to 31st Jan '14) of 2nd Level specializing course in Tunnelling and TBM was completely dedicated to Geological and Geotechnical aspects of Tunnelling. We had expert lectures from Geodata: Mr. Luca Soldo (blog post here) and from National Research council of Italy: Mr. Corrado Fidelibus. Mr. Fidelibus gave us an overview of Soil Mechanics and presentations related to Natural and Induced stress states because of Tunnelling. The lectures also covered the investigation methods,  lab tests, instrumentation and interpretation of Geophysical tests.

Geological studies were explained with a case study on Gotthard Base Tunnel by explaining the geological and geotechnical explorations carried out to detect Piora fault.

Mr. Fidelibus discussed the procedure and the precaution to be taken in calculating the Natural stress states while using in a numerical model. An example of prediction of induced stress state using a FEM program was demonstrated. Key concepts of stress measurements methods were discussed with emphasis on stress relief methods, Hydrofracturing method and flat jack method along with other available methods. Carrara marble project case study was used to demonstrate the use of stress measurement methods.

In addition to the above lectures, following literatures are studied for case studies and to understand the prevailing guidelines:

• "Some new Q-value correlations to assist in site characterisation and tunnel design", N. Barton, International Journal of Rock Mechanics & Mining Sciences 39 (2002) 185–216
• "ISRM Suggested Methods for land geophysics in rock engineering", T. Takahashi, International Journal of Rock Mechanics & Mining Sciences 41 (2004) 885–914

More about the above papers later.

-Senthil Nath G T