Laboratory model tests on laterally loaded piles in plastic clay

This paper presents the results of laboratory model tests conducted to study the behavior of laterally loaded piles installed in plastic clay. The effects of different factors such as pile dimensions, pile material and method of installation were studied. The pile response is presented in terms of load-deflection curves, bending moment distribution, and the p-y curves. The load-deflection curves are generally non-linear specially for large length/diameter (L/d) ratios and large diameters. The ultimate lateral pile capacity increases with the increase in L/d ratio and the pile diameter. The maximum bending moment increases with the increase in L/d ratio and the pile diameter. The maximum bending moment occurs at a depth varying from 0·13L to 0·32L. The bending stresses at the ultimate load are much less than the yielding stress of steel and the flexural strength of concrete. This implies that the deflection controls the design of laterally loaded piles in plastic clays. The experimental p-y curves are different from the existing p-y curves for piles with small diameters and are approximately similar to the existing p-y curves for piles with larger diameters. The bored method of installation gives greater ultimate soil resistance than the preinstalled method for both concrete and steel piles. Overall this study showed that the laboratory model tests with relatively large diameter (>30 mm) can be used to give insight into the performance of laterally loaded piles installed in plastic clays.