The Influence of Water Content Variations on Friction Capacity of Piles in Expansive Soil

Abstract

Seasonal change in tropical climate countries like Indonesia causes variations in soil moisture content. On expansive soil, this condition influences the soil moisture content in the upper few meters, which is generally termed as the active zone. The water content variation induces the changes in physical and mechanical characteristics of the soil and these changes have an impact to the friction capacity of piles. The main objectives of this research are to investigate the influence of water content variations on friction capacity of concrete and steel piles. A series of laboratory experiments were conducted considering the water content variations and pile material. A pile model made of concrete and steel was penetrated to soil sample which was placed in a cylindrical tube. This tube has a diameter about 15 times the diameter of the pile model. The pile model was loaded to failure to investigate the friction capacity. Based on the results from laboratory testing, it can be concluded that the change of water content have a great impact to friction capacity of piles. Friction capacity of concrete and steel piles has decreased up to eight and nine times from drying condition to wetting condition. The results also showed that pile material influenced the friction capacity which steel pile had higher friction capacity than concrete pile.