THREE-DIMENSIONAL NUMERICAL MODELING OF SKIRTED ANCHOR AND RETICULATED MICROPILE FOUNDATION SYSTEMS

Paul Sauco, University of Rhode Island

Abstract

The development of novel foundation systems can render projects ranging from infrastructure rehabilitation to sustainable energy applications more cost-effective. A reticulated micropile system is one such foundation and is studied herein. A reticulated micropile network is a three-dimensional lattice structure that involves the creation of a laterally confined soil-pile composite structure. A numerical analysis using FLAC3D was performed to better understand the mechanics of the ‘knot’ effect in a reticulated micropile system. FLAC (Fast Lagrangian Analysis of Continua) is a numerical modeling software used for advanced geotechnical analyses of soil, rock, constructs, and ground support. The ‘knot’ effect is the formation of an improved soil mass within the reticulated geometry that has been credited with improved group performance. An increase in confining pressure in the soil mass due to shear and dilation of the soil surrounding the pile is the anticipated cause of the ‘knot’ effect. The formation of this soil block, coinciding with an increase in confining pressure and a decrease in shear stress, was observed in both reticulated and plumb pile geometries under vertical compression loading, but it did not improve the group capacity. Improved group performance was observed, however, in groups of both reticulated and vertical piles when laterally loaded.