Effect of Salt and NAPL on Electrical Resistivity of Local Soil and Kaolinite mixed with Sand

Author

Sandeep Goud Burra, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2013

Degree Name

Master of Science

Department

Community Health

First Advisor

Kolay, Prabir

Abstract

Thermal properties mainly electrical and thermal resistivity of soils are very important for various engineering projects such as subsurface transmission of either heated fluids or high voltage buried power cables, and storage & contamination of radioactive waste. Fine grained soils, especially clay, pose a serious problem for conduction of heat due to high electrical and thermal resistivity. These properties mainly depend on the type of soil and its water content. The soil electrical resistivity has been used to predict various soil parameters; various phenomenon occurring in soils such as for obtaining soil water content, degree of compaction, estimating liquefaction potential of soil, detecting and locating geomembrane failures, investigating the effect of soil freezing etc. The efficiency of the electrical resistivity method in various fields led several researchers to work on soil resistivity for over a decade. The present study was designed by taking locally available Illinois soil and commercially available clay (i.e., kaolinite) and mixing it with various percentages of sand ranging from 10-50% forming 12 different soil and clay mixes. To these soil and kaolinite clay mixes laboratory tests were conducted to determine the basic soil properties such as Atterberg limits, specific gravity, particle size distribution, compaction etc. Furthermore these mixes ii were mixed with various percentages ranging from 10-50% of sodium chloride (NaCl), potassium chloride (KCl) and a Light Non Aqueous Liquid (LNAPL) called dodecane to determine the electrical resistivity for each mix. The results indicated that the liquid limit and plastic limit decreases with the increase in sand content for both the mixes. Also the standard Proctor OMC (Optimum Moisture Content) shifted to the left side of the optimum with the increase in sand content from 10-50%. The electrical resistivity for both local soil (i.e., silty clay) and kaolinite clay mixes had a similar trend of decrease in resistivity values with an increase in water and sand content. Interestingly the values of electrical resistivity for local soil and kaolinite clay mixes mixed with sodium and potassium salts had a lower resistivity value when compared to the silty clay and kaolinite mixes added with dodecane.