EXPERIMENTAL STUDY OF MODEL PILED RAFT FOUNDATION EMBEDDED WITHIN PARTIALLY SATURATED COHESIONLESS SOILS

Abstract

This paper presents an experimental study conducted on model piled rafts in partially saturated sandy soil. The aim of the experimental program is to study the effect of matric suction on the load carrying capacity of piled rafts embedded within partially saturated sandy soil .The influence of number of piles are presented and discussed in this study. The piled raft is arranged in different configurations of piles (single, double and triple piled raft with spacing 3.5D c/c) with the same area ratio (raft area to the cross section area of piles) to avoid different contact pressure area and to show the effect of different piles number and its group action. The influence of matric suction (i.e., capillary stresses) in partially saturated zone is typically not taken into account in the conventional design of both shallow and deep foundations so that the present research study the determination and contribution of matric suction towards the load carrying capacity of piled raft. The experimental work consist of 3 models of footing "single piled raft (8.3 x 5) cm, double piled (16.6 x 5) cm and triple piled raft (25 x 5) cm". All these models are loaded and tested under both of fully saturated condition (i.e., matric suction equals to 0kPa) and unsaturated conditions (i.e., matric suction value equals to 6kPa , 8kPa and 10kPa), which are achieved by predetermined lowering of water table.