Analysis of Under-Reamed Piles Subjected to Different Types of Load in Clayey Soil

Abstract

Under-reamed piles with one or more bulbs have been widely used in almost all types of soil to support a range of structures. In some cases, in addition to vertical compressive or uplift loads, piles must withstand a considerable lateral load. A 3-D finite element study using ABAQUS software was conducted to examine the behavior of under-reamed piles in clay soil under pure lateral, pure uplift, and combined uplift and lateral loads. In this study, pile (L/D) ratios of 11.66, 15, 20, and 25 were considered by adjusting the pile length to simulate the behavior of rigid and flexible piles. The piles were modeled as a linear elastic material, and the soil behavior was simulated using the Drucker-Prager constitutive model. The findings show that the lateral resistance of piles with (L/D) ratios of 11.66 and 15 increased slightly when under-reamed piles were used. However, no change in lateral resistance was observed for under-reamed piles with (L/D) ratios of 20 and 25 compared with straight piles. The uplift capacity of under-reamed piles was significantly greater than that of a straight pile. The lateral capacity was marginally influenced by the prior uplift loading, such that it decreased for a rigid under-reamed pile, and increased for a flexible under-reamed pile.

Experimental Work on the Effect of Under-reamed Pile Geometry on the Pullout Capacity of Sand

“…They noticed that the pile pullout load increased with increasing under-ream diameter, number of bulbs, and relative density. Alhassani [15] conducted numerical research using the ABAQUS program to explore the behaviour of the under-reamed pile undr the pullout, lateral, and compression loads. The results of the testing models revealed that the uplift pile capacity of SURP and DURP is much greater than that of a straight pile for all L/D pile ratios.…”