Comparison of floating and end-bearing pile wall barriers for tunnelling in layered soil
Comparison of floating and end-bearing pile wall barriers for tunnelling in layered soil
The construction of an embedded pile wall between the excavation and the foundation, before tunnelling, is a possible mitigation measure against excessive movements. This paper presents a three-dimensional interaction model, using the two-stage approach, the layered half-space theory, and the beam theory for the barrier, to study the efficiency of pile walls in layered grounds. In particular, a two-layer undrained ground model is considered which is key to capturing the fundamental differences between barriers of floating and end-bearing piles (as long as the approximation of linear soil behaviour applies). Results illustrate that, when possible, end-bearing barriers (with tips embedded in stiffer bottom layers) should be preferred to floating pile walls with their tips embedded below the tunnel invert depth to maximise the reduction of surface and subsurface settlements; contrarily, the effects of the barrier on lateral ground movements are minor for both floating and end-bearing barriers.
A. Franza
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
C - Risk analysis and safety evaluation
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