CHARACTERIZATION AND MOBILIZATION OF GYPSIC SOIL ASSOCIATED WITH SUFFOSION CAVE DEVELOPMENT, CULBERSON COUNTY, TEXAS

Dissolution of gypsic soils beneath and proximal to infrastructure in the northwestern Delaware Basin has caused extensive damage to RM 652 in the northern portion of Culberson County, Texas. Increased usage of RM 652 by larger vehicles has encouraged further damage when coupled with the effects of evaporite dissolution, both in gypsum bedrock and in indurated gypsic soils. The region is dominated by numerous evaporite karst manifestations, both epigene and hypogene in origin, and it is evident that evaporite dissolution has had a profound effect on both environmental and anthropogenic processes. Although the study site is located in an arid environment, monsoonal storms in late summer produce significant overland flow and groundwater recharge, resulting in increased suffosion promoting further surficial instability. The resulting eroded soil then flows through fractures and caves within the Castile Formation, producing unstable suffosion caves. These soil caves in indurated gypsic soil are of increased concern as significant potential geohazards when proximal to infrastructure.

A combination of field and laboratory analyses have been implemented for characterization of suffosion processes within gypsic soils proximal to RM 652. Field analyses include documentation of suffosion cave, analyses of soil infiltration and collection of soil cores. Laboratory analyses include chemical characterization of soluble / insoluble fractions of soils, modeling of suffosion processes, and groundwater modeling. These studies will be utilized to improve future construction and mitigation projects within Culberson County, Texas where increased road traffic is heavily impacting infrastructure.