Abstract
Minipiles are generally hollow driven piles, less than 50 mm in diameter and commonly around 2 m in length, without any grouting. Three types of minipile group configuration consisting of individual minipiles battered at 25° with the vertical are investigated in this study to evaluate their lateral load capacities. When the lateral load is applied in the direction of the batter, they are said to be positive battered minipiles, otherwise, negative. The minipile groups under study includes a combination of positive and negative battered minipiles as well as minipiles battered in the direction perpendicular to the direction of the transverse load. The geometries are developed to mimic a tree root system, where roots move in different directions to engage a large volume of soil. The behaviour of these systems is investigated using 1g physical modelling, and it is found that the minipile group with the diagonally outward orientation of 25° battered minipiles have the highest lateral resistance. The minipile group with two positive and two negatives battered minipile performs slightly better than the group with one positive, one negative and two outwardly perpendicular battered minipiles highlighting the role of orientation of the system in its performance. In addition, optic fibres are used to record the strain profile along the minipile shafts in the 1g small scale physical model with results indicating higher strain in the leading piles compared to that in the trailing counterpart at the same lateral load.