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A study on the reinforcing capabilities of Forepoling Umbrella System in urban tunnelling

Le, B. T. & Taylor, R.N. (2016). A study on the reinforcing capabilities of Forepoling Umbrella System in urban tunnelling. Paper presented at the The 3rd European Conference on Physical Modelling in Geotechnics, 1-3 Jun 2016, Nantes, France.


Adequate heading stability is crucial to the safe construction of any tunnel. Insufficient support will lead to ground movements which have the potential to cause damage to existing infrastructure. Congested urban environments have led to a requirement to minimise these tunnelling-induced deformations. Forepoling Umbrella Systems (FUS) have proved to be a beneficial soil reinforcement measure for controlling ground movements due to NATM tunnelling in urban areas. However, there is limited understanding of the influence of tunnel geometry and FUS parameters on its reinforcing efficiencies. A series of centrifuge tests has been conducted to investigate the benefits of FUS using different arrangements of steel pipes placed in a model tunnel heading at various depths. The results show the importance of the steel pipes near the tunnel spring-line and the embedded lengths on the reinforcing effects of forepoles. In addition, relative benefits of forepole location and embedded length are shown to vary as the soil cover above the tunnel changes.

Publication Type: Conference or Workshop Item (Paper)
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Departments: School of Science & Technology > Engineering
Text - Accepted Version
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