INTEGRATED PHYSICO-CHEMICAL CHARACTERIZATION AND LIME STABILIZATION OF DISPERSIVE SOILS IN FLOOD RETENTION POND PROJECTS

Abstract

Dispersive soils constitute a critical geotechnical and environmental concern in flood retention pond systems due to their propensity for deflocculation, internal erosion, and turbidity generation under low-electrolyte conditions. This study presents an integrated physical, chemical, and mineralogical characterization of soils excavated from flood retention pond projects in Prachin Buri province, Thailand, and evaluates the efficacy of lime stabilization in mitigating dispersive behavior. Physical dispersion tests (crumb, double hydrometer, and pinhole) were complemented by chemical indices including %Na, sodium adsorption ratio (SAR), and concentrations. X-ray diffraction identified montmorillonite as the dominant clay mineral governing high dispersivity, while compaction parameters (MDD-OMC) and fines content elucidated the mechanical susceptibility of these soils to moisture-induced breakdown. Stabilization trials using high-purity hydrated lime (98.35% CaO), confirmed via XRF, demonstrated substantial improvements; lime dosages of 0.5-2.5% reduced the degree of dispersion from 87% to 13% and altered pinhole classifications from D1 to ND1, indicating a transition to non-dispersive behavior. Turbidity measurements reached up to 19.63 NTU in dispersive-soil zones, corroborating sodium-induced colloidal release observed in laboratory testing. Taken together, the findings underscore the necessity of integrating physical, chemical, and mineralogical criteria for reliable identification of dispersive soils and confirm that lime stabilization is a highly effective intervention for reducing dispersivity, controlling turbidity, and enhancing the environmental performance of flood retention pond infrastructure.