CEM-DSR-based explicit solution of limit expansion pressure in unsaturated soils and its application

In this study, an explicit solution for the limit expansion pressure of cavity expansion in unsaturated soil, which follows a hydraulic coupling constitutive model, was proposed based on the cavity expansion method (CEM) and deep symbolic regression (DSR). In detail, a semi-analytical elastic-plastic solution for cavity expansion in unsaturated soils was obtained based on the unsaturated critical state model; hence, a database was created. To obtain an explicit solution for the limit expansion pressure, DSR, which is a gradient-based approach to symbolic regression based on reinforcement learning, was applied. Subsequently, 13-and 4-parameter regression analyses were conducted, with satisfactory results being obtained. Finally, based on the proposed explicit expression, a theoretical calculation model for the jacked-pile penetration resistance in unsaturated soils was established. The study presented in this paper opens up possibilities for obtaining theoretical solutions to issues such as predicting pile driving performance in unsaturated soils.