Laboratory Evaluation of Archie's Law in Kaolinite-Rich Landfill Soil Under the Leachate Influence: A Mineralogical Control and Interpretation Limited by Uncertainty

Abstract

Landfill contamination remains frequent global environmental challenge, particularly in tropical regions where hydrogeochemical conditions can speed up subsurface transport processes. However, the sophistication of electrical resistivity interpretation in clay-rich and chemically aggressive soils remains highly debated. This laboratory-scale resistivity study evaluated the validity of Archie's Law using kaolinite-dominated soil gained from a tropical landfill (Bakung Landfill, Indonesia) under controlled conditions of unsaturation, pure water saturation, and leachate saturation. X-ray diffraction (XRD) analysis indicated that kaolinite as dominant mineral phase, while Scanning Electron Microscope (SEM) observations revealed discontinuous in increasing the clay layers of pore tortuosity without forming conductive tissue. Although, there was significant ionic interference from leachate of landfill, laboratory resistivity measurements maintained consistent exponents, resulting cementation exponents between 2.22 and 2.53 (R² = 0.69–0.81). Statistical analysis was analyzed through regression confidence intervals, bootstrap resampling with 10,000 iterations, and Monte Carlo uncertainty propagation including realistic laboratory uncertainties (resistivity ±3%; porosity ±2%). The confidence limits of Monte Carlo, reaching (1.80–2.95) producing the parameter stability in the granular-clay transition. These findings indicated that kaolinite-rich tropical landfill soils represent a transitional electrical system where laboratory calibrated Archie parameters remain statistically stable, strengthening the environmental reliability of resistivity-based landfill risk evaluation.