Abstract
This paper pivots on conceptualising tree-root architectures for designing resilient, multifunctional foundations. Shallow-depth driven battered minipile systems with varied orientations of constituent minipiles are presented in this study and evaluated for their performance. The first step was to perform full-scale field tests of single vertical and battered (25°) minipiles under vertical uplift and compressive loads at a cohesive (fine-grained) soil site. This was followed by subjecting four minipile group configurations, with two cap-width types, to uplift and compression loading. The per-minipile capacity within a group is presented as a non-dimensional value to account for heterogeneous soil conditions. One of the group configurations was used to calibrate a numerical model and to simulate the field test program, assuming uniform soil properties. Interaction among the minipiles within the group is inferred from the soil shear stress profile and the minipile bending moments and axial forces. The contribution of each minipile within a group to the compressive and uplift capacities varies with the cap width, spacing, and position of the minipiles. The projected geometric areas of these minipile systems within a group are observed to influence their vertical capacity. The group efficiency factor for all minipile groups exceeded unity for the given pile and soil parameters.