NUMERICAL ANALYSIS OF INFLUENCE OF DEEP EXCAVATION ON NEARBY EXISTING TUNNEL

B. Viswanath, Krishna. A, Padmashree M. Kallimani

Abstract: The constantly increasing urbanization of the metropolises requires more and more realization of a fast and efficient transportation network. Underground transport lines often constitute an ideal solution in term of efficiency and low nuisance for the environment. The technical advancements brought to the underground excavation methods allow the achievement of projects in difficult environmental conditions, especially in urban areas. Providing space for parking, public amenities, etc in multi-storey buildings at town centers has created a need to go deep excavations into ground. The construction of deep excavations in the urban environment is a technically challenging problem. Underground construction may be in the vicinity of already existing tunnels. Deep excavations may have impact on the adjacent tunnels. Such excavation will impose significant influence on the tunnel linings, including changes of stress and deformation. Such effects are observed due to the “space effect” of excavation. The study involves the analysis of influence of deep excavation on the existing tunnel, structural impact on the tunnel lining and measures for controlling the soil and tunnel deformation using finite element software Plaxis (2D). In this study the influence of deep excavation on the existing tunnel with varying position is analyzed. Analysis is carried out by considering tunnel just below the excavation and just beside the excavation. Effect of excavation on tunnel lining and displacement of tunnel due to excavation is observed. Also Analysis involves soil improvement technique to reduce impacts of excavation on tunnel. Grouting method is adopted for the analysis and its role in controlling the effects on tunnel is analyzed

Keywords: Deep excavation, Plaxis 2D, Strut, Displacement, Heave etc…

DOI: https://doi.org/10.15623/ijret.2014.0318020