Experimental Investigation of the Uplift and Lateral Bearing Capacity of Root Piles

The root pile, a new type of pile foundation with a variable cross-section, is introduced. The mechanism of root piles under uplift and lateral loading and the construction process are presented and discussed. The bearing capacity of root piles under uplift loading, lateral loading, and combined uplift and lateral loading was compared with that of conventional straight piles through field loading tests, which were performed on two straight piles and two root piles. The results indicate that the uplift and lateral bearing capacity of root piles is significantly greater than that of straight piles; the combined uplift and lateral loading has almost no influence on the uplift bearing capacity of single piles, but would weaken their lateral bearing capacity; the roots are engaged gradually from the top to the bottom under uplift loading; the resistance of the roots increased substantially because of the interaction between the soil and roots; however, the side friction of the pile shaft above the roots decreased because of this interaction. Increasing the burial depth of the roots could improve the performance of the roots for building applications.