Experimental study of heave control technique for expansive soil using micropiles and geotextile layers

Heaving of expansive soil is a crucial phenomenon due to their excessive volume changes with variation in moisture regime, which in turn leads to substantial distress to the structures built on them. The main objective of this study is to evaluate the effectiveness of micropile and performance of geotextile to resists upward movement of structures built over expansive soil. For this study, the expansive clay compacted in a steel box of size 50 cm × 50 cm × 50 cm to a depth of 20 cm and analyzed with two different methods to control heaving of soil. Firstly, four micropiles of 16 and 20 mm in diameter were inserted into the soil with and without frictional resistance. The micropiles were fastened to the corners of footing of size 15 cm × 15 cm × 0.5 cm, with nut and bolt system. Further, Geotextiles were reinforced below the footing at a vertical spacing of 0.1B and 0.3B as single and double layers. Then the soil was saturated with water and the upward movement of model footings (swelling) was monitored with time. Test results showed that maximum heave reduction was 79% for 20 mm diameter micropiles with frictional resistance.