Evolution of Seepage and Stability Characteristics of Lateritic Soil Slopes Containing a Tension Crack Zone Under Rainfall Infiltration

Tension crack zones may occur at the surface, particularly the crest, of soil slopes for various reasons. The presence of tension crack zones will provide preferential channels for water flow and considerably reduce slope stability under rainfall infiltration. This study aims to examine the influence of tension crack zones on the seepage and stability characteristics of soil slopes. To this end, the numerical model of a lateritic soil slope containing a tension crack zone of various distribution parameters (i.e., density, location, depth, and angle) is created. Then, physical model tests are conducted to validate the numerical model. Finally, the evolution of seepage characteristics and safety factors of the cracked lateritic soil slope is analyzed considering rainfall infiltration. The results indicate that neglecting the crack zone or replacing the crack zone with a single crack will overestimate the safety factor by 0.15–0.23 and 0.06–0.08, respectively. Generally, a greater crack density or crack zone depth causes a larger transient saturated zone (TSZ), while a larger crack zone angle often leads to a smaller TSZ. The formation of TSZ obviously reduces the safety factor of the soil slope. Among the examined crack parameters, the crack zone depth has the most significant influence on both the TSZ and safety factor. Thus, the development of deep crack zones must be strictly restrained to ensure the long-term stability of lateritic soil slopes.