Table of Contents
International Scholarly Research Notices
Volume 2014 (2014), Article ID 828792, 13 pages
http://dx.doi.org/10.1155/2014/828792
Research Article

Study of Surface Displacements on Tunnelling under Buildings Using 3DEC Numerical Modelling

1Department of Civil Engineering, National Institute of Technology Karnataka, Surathkal 575025, India
2Department of Mining Engineering, National Institute of Technology Karnataka, Surathkal 575025, India

Received 21 June 2014; Revised 21 August 2014; Accepted 31 August 2014; Published 30 October 2014

Academic Editor: Antonio Apicella

Copyright © 2014 Nalini Rebello et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Underground structures at shallow depths are often constructed for metro lines, either in loose or dense layered soils. Tunnelling in urban areas is predominantly under surface structures and on tunnelling, innumerable changes in the form of distortion take place in strata surrounding the tunnel. Extent of displacement/damage to buildings or the tunnel-soil structure interaction depends on the type of building and nature of strata. Effect on displacements has been less studied in granular soils compared to other types of soils like clays. In this paper, parametric studies are conducted to find the displacements at surface, in granular soil conditions, due to varying building storeys and building eccentricities from the tunnel centre line. Effect of presence of geosynthetic layer under footings is further studied. Prior to the parametric studies, validity of the model used is checked with field data available for a stretch of tunnel in South India. Results of simulation studies reveal that inclusion of building reduces displacements at the surface in the dense strata. In very dense strata, the displacements increase as compared to the case without a building. As the centre of the building moves away from the tunnel centre line, settlement above the tunnel matches displacements in the case without building. Applicability of 3DEC software is checked with respect to the present study.