Long-term field heave studies on various foundation techniques in expansive soils
- Vol.51(5), Oct
- Switzerland Springer 2021
- 909-923p.
Expansive soils being susceptible for moisture variations undergo cyclic seasonal movements that pose serious stability concerns for structures resting on them, especially when they are lightly loaded ones. The concerted efforts made by various researchers across the world enabled them to develop remedial solutions to mitigate these problems with varied degree of success. The present work is an effort to study the relative performance of the different remedial techniques in vogue and those proposed in the recent years. These techniques were adopted below the shallow footings at a site on NIT Warangal campus where natural expansive clay bed is present. This study revealed that the sand cushion and CNS cushion could reduce the heave by 56 to 64%; but in case of sand cushion, an increasing trend of heave with number of cycles of wetting and drying was observed. The chemical alteration by lime could reduce the heave by 59% and by CaCl2 and CaCl2–Na2SiO3 the heave could be reduced by 70 and 73%, respectively. The recently promulgated concrete and granular anchor piled footings have shown the heave reduction up to 63 and 78%, respectively. Further, it is found that the combined effect of CNS cushion along with chemical modification and/or tension/anchor piled footing systems were found to be synergistically more effective than individual techniques in controlling the seasonal movements of footings and flooring/lining panels. Interestingly, none of these remedial techniques could overcome the shrinkage movements though these movements are observed to be insignificant in case of piled footings.