Sustained Collapse Testing of Soluble Soils in the Moab Valley

Soluble soils in the Moab Valley of southeastern Utah pose a significant geotechnical challenge due to the presence of gypsum, anhydrite, calcite, and other minerals derived from the weathered Paradox Formation. While traditional ASTM D4546 collapse testing captures the initial response of these soils upon wetting, it may underestimate long-term collapse potential driven by mineral dissolution under repeated moisture exposure. This study introduces a modified Sustained Collapse Test to evaluate progressive collapse potential in soluble soils under sustained wetting conditions. Soils from two geologically distinct sites were tested under constant load and inundated with distilled water, municipal tap water, and rainwater to simulate natural and infrastructure-related wetting. Results demonstrate that progressive collapse and porewater conductivity evolve over time, with dissolution behavior strongly influenced by both soil mineralogy and water chemistry.