Research Projects

Tunnel collapses in soft residual slopes, such as the Pernem Tunnel in India, are common due to the variability in soil properties. The design and construction of tunnels in such soils are often based on empirical approaches and experience, leading to the lack of proper design guidelines for stability analysis. This project proposes conducting a stability analysis of a tunnel in highly heterogeneous residual soil slope using random finite element analysis. The methodology includes laboratory experimentation, deterministic finite element analysis, and random finite element analysis. The residual soil will be collected from at least 10 sites in the Konkan region of India, and strength properties and suction characteristics will be obtained through laboratory tests. A two-dimensional plane-strain undrained stability study will be performed using both deterministic and random finite element analyses in ABAQUS software. The deterministic analysis will validate the model, while the random finite element model will simulate random fields of strength parameters. The random finite element analysis will be conducted for varying spatial parameters, and the probability of tunnel failure will be quantified to obtain design parameters for varying coefficient of variation and autocorrelation distance. The design charts will be useful in determining design parameters for tunnel stability analysis in heterogeneous soil slopes.