EVALUATION OF HYDRAULIC CONDUCTIVITY VARIATIONS INDUCED BY SOIL CRACKING UTILIZING A MODIFIED SEEPAGE TESTING APPARATUS

Abstract

Landslides are a common hazard during the rainy season, particularly in hilly regions with hard, well-compacted soil layers. Due to the low seepage capacity of such soils, rainwater infiltrates slowly, leading to increased surface runoff. While this slow infiltration generally enhances slope stability by reducing pore water pressure, the presence of deep surface cracks can trigger landslides by facilitating rapid water seepage into the subsurface. The accelerated infiltration through cracks is governed by variations in the soil’s seepage coefficient, yet research on this phenomenon remains limited. This study investigates the seepage coefficient of cracked soil using a newly developed modified seepage apparatus designed specifically for fractured soils. Experimental results demonstrate that the seepage coefficient in cracked soil ranges from 4.23 × 10⁻⁵ to 1.01 × 10⁻³ cm/s, indicating significantly higher permeability compared to intact soil. Furthermore, the seepage coefficient increases proportionally with crack width and depth, and the presence of sand infill material within soil cracks further modifies seepage behavior, highlighting the critical role of crack dimensions and composition in governing infiltration rates. These findings provide valuable insights into landslide initiation mechanisms, emphasizing how soil fracturing and infill materials exacerbate rainfall-induced slope failures. The study underscores the need to account for crack-induced seepage and infill effects in slope stability assessments, offering a foundation for improved landslide risk mitigation strategies in vulnerable regions.