Behaviour of under-reamed piles in sand under lateral and vertical loading

The project will involve fabricating small sized FRP and steel rods fitted with circular discs at the bottom and jacked through a layer of sand in a wooden box. Using a pulley system, the tops of the rods will be tied to horizontal steel wires to allow incremental weights to be applied hence pulling the rods horizontally. Measurements of load-deflection values will be recorded until failure is approached. The rods diameters and disc sizes may be varied to assess the effects on load-deflection pattern. Afterwards, a literature search will be conducted to study a few of the most common mathematical methods of predicting load-deflection relationship for such geotechnical structures of full scale size. These will be applied to analyse the model piles (rods) along with measurement of the basic properties of the sand e.g. shearing strength parameters (shear box tests), grain size distribution, density-moisture relationships (dynamic compaction in mould) and moisture condition value.

The objective of the research is to assess the applicability and reliability of existing theoretical/ empirical methods of analysis of laterally loaded cylindrical piles to under-reamed piles. There is very little information on behaviour of under-reamed piles in lateral loading so the work will likely provide new insights into these special pile types, which are currently becoming more common in the geotechnical engineering area. Time permitting, further investigations will be carried out using ANSYS finite element software or PLAXIS 3D to perform numerical simulations of the model piles hence make comparisons with the measured data.