Stabilized Soil Evaluation Using Laboratory Electrical Resistivity Cell Bhangale, L.A. Bhosale, S.S. Professor e-mail: [email protected]e-mail: [email protected]Department of Civil Engineering, College of Engineering Pune, Pune ABSTRACT Electrical resistivity is one of the most widely used geophysical methods of investigation. In this paper results of lime stabilized expansive soil properties determine by specially developed laboratory resistivity cell are presented. The developed resistivity cell works on two electrodes as against field method of four electrodes. Efforts are made to correlate the strength properties such as Unconfined compression strength and CBR of lime stabilized and untreated expansive clay with electrical resistivity. Indian Geotechnical Conference – 2010, GEOtrendz December 16–18, 2010 IGS Mumbai Chapter & IIT Bombay 1. INTRODUCTION Expansive clay causes foundation damage by excessive deflections or differential movement. In pavement construction , the good quality soil is needed for the sub grade which being costlier matter in present days an alternative method of strengthening local soil by various techniques have gain immense importance. In India the majority area of the states namely, Maharashtra, Karnataka, Andhra Pradesh, Madhya Pradesh are covered by the expansive soil like black cotton soil. Lime stabilization is the well known method for such type of soil. The strength of lime stabilized soil is measured by laboratory UCS and CBR tests which are laborious and time consuming. So to save time, indirect non destructive testing methods like Electrical resistivity may be used. Abu-Hassanein (1996) and Mc Carter (1984) have correlated LL, PL and compaction characteristics of clay with electrical resistivity. Electrical Resistivity probe and box are developed by Sreedeep et al. (2004) to correlate the soil degree of saturation with the four pin electrical resistivity method .This paper presents two electrode laboratory electrical resistivity cell which is used for correlating UCS and lab CBR of lime stabilized expansive clay with the resistivity. 2. TWO PIN ELECTRICAL RESISTIVITY CELL The simple principle of resistance measurement and resistivity calculation is shown in Figure 1. Ratio of cross sectional area divided by the length is called as geometric/ box factor. This principle has been used to develop the laboratory electrical resistivity cells. The Resistivity cell is Fig. 1: Resistivity Measurement (Source – Google Images) rectangular shaped acrylic box such that cylindrical soil sample would fit into it and has two circular copper electrodes at two ends of the box with acrylic end caps to hold the end electrodes tightly against the soil sample. (Fig. 2) The resistance is measured between the two electrodes by standard resistivity meter used for conventional four pin electrical resistivity. Fig. 2 Electrical Resis Copper Electrode Bottom side Top side End Cap Soil Sample Fig. 2: Electrical Resistivity Cell of Box Factor 6.16 Bottom Side Top Side
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Stabilized Soil Evaluation Using Laboratory Electrical ...igs/ldh/conf/2010/articles/085.pdfStabilized Soil Evaluation Using Laboratory Electrical Resistivity Cell 345 untreated soil
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Stabilized Soil Evaluation Using Laboratory Electrical Resistivity Cell