TAI Journal (A Half Yearly Technical Journal of Indian Chapter of TAI)
Year : 2018, Volume : 7, Issue : 2
First page : ( 52) Last page : ( 60)
Print ISSN : 2277-2820. Online ISSN : 2278-4713.

Finite Element Analysis of Factors Affecting the Ground Movements & Geotechnical Capacity Loss Induced due to Shield Tunnels

Sharma Animesh

AFCONS Infrastructure Ltd, Kolkata

Online published on 20 April, 2019.

Abstract

Due to exponential increase in urbanization, there is growing need for a systematic mass transportation system in developed and developing countries. In urban locations, due to limited availability of land, the need for systematic mass transit system even grows and the consequent solution becomes diffi cult. A reasonable solution is development of underground transportation system like tunnels. With advancement in technology, use of Tunnel Boring Machines has been increased for making underground tunnels. An inevitable aspect of construction of underground tunnel is the ground movements associated with it. Due to the urban location, often the construction of tunnels impact many buildings and structures located within its close proximity. An important aspect for evaluating the impact of tunnelling on existing structures is the settlements or the ground movements induced due to tunnelling. With that under consideration, the current study encases the assessment of settlements induced due to Bored Tunnels using fi nite element method. Current study undertakes a detailed analysis of the parameters affecting the ground movements & also investigates the geotechnical capacity loss associated with the ground movements. The observed results from fi nite element analysis are then compared with the theoretical results. From the study & subsequent comparison, it can be said that the geotechnical parameters form an important aspect for determination of ground movements. A precise range of settlements can be obtained by accounting the geotechnical parameters in the assessment. The study also investigates the pattern of sub-surface settlements with respect to the depth. The study also validates the phenomenon of the associated geotechnical loss induced due to bored tunnels. This has been assessed by simulating twin bored tunnels i.e. two tunnels in close proximity, with one passing fi rst, followed by the second bored tunnel. The results suggested that there is a considerable reduction in geotechnical capacity loss generated due to associated ground movements. The study concludes that upon accounting the geotechnical factors, an even precise assessment of the ground movements can be arrived at. Precise assessment of behaviour of ground movements will account for an even precise assessment of the impact upon the structures or buildings within proximity.

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Keywords

Tunnels, Ground Movements, Geotechnical Loss, Settlements, PLAXIS, Finite Element Analysis.

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