DBPapers
DOI: 10.5593/SGEM2014/B12/S2.054

GEOTECHNICAL DESIGN AND MONITORING OF A DEEP EXCAVATION. COMPARISON BETWEEN MEASUREMENTS AND CALCULATION

H. Popa, S.Manea, L. Batali
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-08-7 / ISSN 1314-2704, June 19-25, 2014, Book 1, Vol. 2, 417-424 pp

ABSTRACT
Designing high buildings, with 10 – 20 stories aboveground and several underground stories in dense urban areas supposes deep excavation enclosures, having neighboring structures at the property limit. Designing and building such works imply a series of activities which have to be lead and controlled rigorously from technical and scientific point of view. Paper presents the authors’ approach for a case study, starting from the geotechnical investigation of the site, mathematical modeling and design, to the building survey, monitoring and model validation. The case study presents 2 office buildings with 8 – 15 stories, with a common basement developed on 4 underground levels, leading to a 15 m deep excavation. Paper presents the geotechnical conditions and parameters issued from in situ and laboratory tests. Working enclosure has been designed using diaphragm walls. The chosen working technology was the “top – down” method and the calculations have been performed accordingly. The numerical modeling has been performed using both reaction coefficient and finite element methods. The execution is accompanied by a rigorous monitoring program for the enclosure and for the neighboring buildings, including piezometers, inclinometers within the diaphragm walls, topographic marks for horizontal and vertical displacements of the walls and buildings. The paper presents how the measurements were used to validate the modeling hypotheses, according to technological phases.

Keywords: deep excavation, retaining wall, numerical modelling, experimental measurements