On the influence zones induced by shallow tunnelling in soft soils

Conference paper (2017)

Authors

N. Vu Minh Geo-engineering - CEG , Hanoi University
W. Broere Geo-engineering - CEG
J.W. Bosch Geo-engineering - CEG
Research Group
Geo-engineering (CEG) (TU Delft)
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Published Date

2017

Language

English

Reuse Rights

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Faculty

Civil Engineering & Geosciences

Department

Geoscience and Engineering

Research Group

Geo-engineering

Abstract

The extent of the influence zone affected by tunnelling depends on the amount
of over-excavation and stress changes induced in the soil, normally represented as a value of volume loss. This study combines upper and lower estimates of volume loss for different soil conditions and ground movement analysis for various cover-to-diameter ratios C/D in order to identify the zones around the tunnel affected by shallow tunnelling. These zones are combined with risk categories of damage to existing buildings to identify whether mitigating
methods or additional control measures during tunnelling would be needed for a safe and damage-free tunnel construction. The boundaries of these influence zones have been derived both for surface and subsurface analyses. Although there is only a small number of available case studies, they show good agreement between the analysis and observed data. The influence of soil parameters on the influence zones is also investigated. This study shows that by
improving soil properties, the boundaries of influence zones can be controlled. The results in this paper are also the first theoretical basis for estimating the requirements for mitigating measures in shallow tunnelling in soft soils.