Geotechnical Centrifuge Modeling of Tunnel Behavior in Difficult Soft Soil Conditions
Geotechnical Centrifuge Modeling of Tunnel Behavior in Difficult Soft Soil Conditions
This paper presents a synthesis of an investigation into the long-term behavior of tunnels excavated in challenging soft soil conditions. A reconstituted clay, created by mixing 50% kaolin and 50% diatomaceous soil (50K50DS), was developed to replicate the high compressibility and low permeability of natural lacustrine deposits while reducing consolidation time. One-dimensional consolidation tests demonstrate that the mixture increases the coefficient of consolidation by a factor of approximately three within the stress range relevant for urban tunnels, while maintaining strength and compressibility compatible with soft clays found in cities such as Bogotá and Mexico City. The material was subsequently utilized in centrifuge models simulating a circular tunnel embedded in a soft layer overlying a hard stratum, subjected to regional groundwater drawdown. The experimental program incorporated pore pressure transducers, surface settlement gauges, and earth pressure cells installed around the tunnel lining. Test results indicate that pore pressure dissipation leads to significant regional settlements and a progressive increase in vertical and tangential loads acting on the lining, with the largest increments concentrated at the crown. Comparisons with numerical finite element simulations reveal good agreement for both settlements and lining pressures, supporting the use of the 50K50DS mixture and centrifuge modelling as effective tools for studying the long-term response of tunnels in soft ground under pore water pressure drawdown (Rodríguez-Rebolledo et al., 2023; Santos et al., 2024; Shahu & Reddy, 2011; Caicedo et al., 2015).
Juan Felix Rodriguez Rebolledo; Bernardo Caicedo; R. F. Perez Leon; Alan Ribeiro-Santos
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Special Session 1: Physical modelling – from Practice/Industry to Academia
https://doi.org/10.53243/ICPMG2026-187