Sensitivity Analysis of Loess Stability to Physical and Mechanical Properties: Assessment Model

Due to their low strength, high compressibility, and collapsibility, loess deposits are susceptible to large deformation and landslides during tunneling. An objective, scientific approach to stability assessment is urgently required. To reveal the sensitivity of loess's stability to its physical and mechanical properties and further establish a stability assessment model, the boreholes and monitored settlements of 30 tunnel sections were collected from the tunnel project in Yan'an, China, and analyzed by rough set theory. The results show that the stability of loess deposits during tunneling is more dependent on the strength parameter phi (35.295%) than its c (26.471%), and dry density (20.588%) contributes the most to the stability in physical properties, followed by water content (11.764%) and void ratio (5.882%). Then, with the physical and mechanical parameters as the index system, a stability assessment model based on extension theory was established and finally applied to the practical project for verification. This study helps in getting an insightful understanding of loess's stability and provides a reference for future studies and tunnel construction through loess deposits.