Software Discussion-PPT Presentation

PPT Presentation
Pdf Summary
The document presents a software comparison and stability assessment for an A-frame micropile system designed to stabilize a landslide in Hinton, West Virginia. Analyses used limit-equilibrium and finite-element tools, including GEOSTASE, PLAXIS 2D, FLAC3D, and Rocscience programs.<br /><br />For the GEOSTASE/PLAXIS assessment, assumptions were adjusted to address limited site data: both micropile bars were modeled as 2.25 inches in diameter, rock-socket depths were revised, and colluvium strength was back-calculated to a friction angle of 24° and cohesion of 85 psf. The analyses generally agreed. With micropiles, the static factor of safety was about 1.55 and predicted movement was only 0.5 inches. Under a modest seismic case (PGA 0.07), the factor of safety remained around 1.2 and displacement was small, but the micropile system was judged unstable. In the stronger seismic case (PGA 0.35), the system was highly unstable and predicted movement reached roughly two feet.<br /><br />FLAC3D modeling highlighted complex soil–structure interaction and multiple potential failure modes: passive soil failure near the cap and bending or shear failure of micropile bars and casing. The beam itself was not critical; its stiffness could contribute to premature pile failure. The three-dimensional model performed worse than the 2.5D section, with global safety estimates around 1.15–1.25.<br /><br />Rocscience analyses showed baseline factors of safety near 0.92–0.97, increasing to approximately 1.59–1.68 with supports, exceeding the stated target of 1.5 across the modeled methods.<br /><br />Overall, the presentations emphasize that A-frame micropile performance depends on realistic modeling of geometry, construction stages, groundwater, and structural interaction. Bending and shear—not necessarily axial capacity—may control. Designers should pay particular attention to pile-cap connections and failure mechanisms; a connected second row of piles was suggested as a potentially stronger configuration.
Keywords
A-frame micropile
landslide stabilization
Hinton West Virginia
GEOSTASE
PLAXIS 2D
FLAC3D
Rocscience
factor of safety
soil-structure interaction
seismic analysis