Determination of soluble mineral content in Las Vegas soils
Lower basin areas in the Las Vegas Valley contain soils with large amounts of soluble minerals. Dissolving and leaching processes due to water intrusion into foundation soils containing soluble minerals can cause a volume reduction of the soil which in turn causes structural stress. Soil improvement recommendations for soluble soils are based upon the amount of soluble minerals of a parent soil. This study reports the results of research to develop a correlation between the electrical conductivity and the concentration of soluble minerals in aqueous soil extracts. Correlations were developed by measuring the total dissolved solids and conductance of aqueous soil extracts of water to soil ratios from 100:1 to 2:1. A best fit correlation curve was developed from the results that relates the soluble mineral concentration to measured conductance of soil extracts. An optimum water to soil ratio that ensures that all minerals are dissolved in solution prior to measuring conductance was identified. Finally a test procedure utilizing the best fit correlation curve is proposed.