A Comprehensive Analysis of Root Pile Dynamics Under Rotary Machine Induced Vertical Harmonic Vibrations
摘要
Machine foundations require careful design for minimal deformation and safety. Engineers introduced root piles, which combine roots with traditional piles, to offer additional anchorage resistance. A finite element analysis was performed on the base pile with roots having a length of 10m and a diameter of 1.2m. The root was modelled as a linear elastic material, while the c-φ soil adhered to the Mohr-Coulomb failure criterion. This research performed a parametric analysis of root piles exposed to vertical vibration caused by a rotary machine. Various factors were taken into account, including pile characteristics (length and diameter), root properties (length and cross-sectional area), external forces (static and dynamic loads), and layer properties (number of roots per layer, number of layers, and spacing between layers). Time versus amplitude and frequency versus amplitude curves were derived for an eccentric moment of 1.5 N-m. The results indicated that root piles outperformed conventional piles under vertical vibrations by effectively reducing resonant amplitudes. Increasing the root length and cross-sectional area minimised resonant amplitudes up to a certain threshold, beyond which the advantage of roots diminished. The soil-pile system exhibited nonlinear behaviour, marked by lower resonant frequencies and amplitudes that do not increase proportionally with the load.