Groundwater characterization of a heterogeneous granitic rock massif for shallow tunneling
DOI:
https://doi.org/10.1344/105.000001773Keywords:
Inflow, Shallow tunneling, Fault-zone, ModelingAbstract
Shallow tunneling may encounter a number of problems, the most important of which is high water inflows in transmissive areas that are often associated with fractures or discontinuities. Moreover, research into shallow tunneling may be limited by the duration and cost of the civil engineering works. Two important aspects that are often overlooked are: variable groundwater behavior of faults (conduit, barrier, conduit-barrier), and role of groundwater connectivity between fractures that cross the tunnel and the rest of the rock massif. These two aspects should be taken into account in the geological and groundwater characterization to correct the tunnel design and minimize hazards. A geological study and a preliminary hydrogeological characterization (including a prior steady state investigation and cross bore-hole tests) were carried out in a granitic sector during the construction of Line 9 of the Barcelona subway (B-20 area). The hydrogeological conceptual model was constructed using a quasi-3D numerical model, and different scenarios were calibrated. Faults and dikes show a conduit-barrier behavior, which partially compartmentalized the groundwater flow. The barrier behavior, which is the most marked effect, is more prominent in faults, whereas conduit behavior is more notable in dikes. The characterization of groundwater media entailed a dewatering plan and changes in the tunnel course. This enabled us to construct the tunnel without any problems.
Downloads
Published
Issue
Section
License
Copyright (c) 2012 J. FONT-CAPÓ, E. VAZQUEZ-SUÑÉ, J. CARRERA, I. HERMS

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Copyright
Geologica Acta is the property of the UB, GEO3BCN, IDAEA and UAB. Geologica Acta must be cited for any partial or full reproduction. Papers are distributed under the Attribution-Share Alike Creative Commons License. This license allows anyone to reproduce and disseminate the content of the journal and even make derivative works crediting authorship and provenance and distributing possible derivative works under the same or an equivalent license.
Author Rights
Authors retain the copyright on their papers and are authorized to post them on their own web pages or institutional repositories. The copyright was retained by the journal from the year 2003 until 2009. In all cases, the complete citation and a link to the Digital Object Identifier (DOI) of the article must be included.
The authors can use excerpts or reproduce illustrations of their papers in other works without prior permission from Geologica Acta provided the source of the paper including the complete citation is fully acknowledged.