The term expansive soil refers to soils that have a tendency to swell when their moisture content is allowed to increase. Moisture can come from rain, flooding, leaking water or sewer lines, or from a reduction in surface evapotranspiration when an area is covered by a building or sidewalk. The term fissured soils is also used for these soils because they have a tendency to shrink and crack when moisture is allowed to decrease. Soils containing the clay mineral montmorillonite generally exhibit these properties (Komine and Ogata, 1996; Rao and Triphaty, 2003; Sivapullaiah et al. 1996; Wayne et al. 1984). There are many useful correlations for identifying potentially expansive soils. It may also be possible to identify them visually. Visual indications include (Wayne et al. 1984):1) Large, deep shrinkage cracks that occur during periods of drought2) Soil is rock hard when dry, but very sticky and soft when wet3) Damage to surrounding structures due to soil expansionExpansive soils are found primarily in arid and semiarid regions of the world. The presence of montmorillonite clay in these soils gives them swelling and shrinkage potential (Chen, 1988). Expansive soils cover almost 20% of the land area of ​​India and include almost the entire Dean plateau, western Madhya Pradesh, parts of Gujurat, Andhra Pradesh, Uttar Pradesh, Karnataka and Maharastra (Gopal Ranjan and Rao, 1991). Expansive soils are a worldwide issue that poses many challenges to civil engineers. These are considered a potential natural hazard, which can cause extensive damage to structures if not properly treated. Such soils swell when they have access to water and shrink after they dry (Al-Rawas et al. 2002). In general, expansive soils have...... middle of paper...... ssification tests. Atterberg limits are usually used to identify swollen terrain. The increase in plasticity index is considered an indicator of increased swelling potential. Chen (1988) presented a swelling soil classification based on soil plasticity index as shown in Table 2.1.Table 2.1 Expansive soil classification based on plasticity indexPI (%) Swelling potential0 - 15 Low10 - 35 Medium35 - 55 High55 and above Very High Classification based on shrinkage index has proven to be unreliable in predicting soil swelling potential. However, shrinkage index can be used with plasticity index for identification as shown in Table 2.2..Table 2.1 Expansive soil classification based on plasticity index and shrinkage indexPI (%) YES (%) Degree of expansion< 12 < 15 Low12 - 23 15 - 30 Medium23 - 32 30 - 40 High> 32 > 40 Very high