Slope Stability Monitoring with Remote Interferometric Phase Radar-PPT Presentation

PPT Presentation

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Victory Village is a 54-unit, 2- to 3-story residential development in Fairfax, California, covering approximately 51,000 square feet. The site occupies a slopewash-filled valley surrounded by bedrock that inclines beneath the property. Subsurface soils include very loose to loose clayey sands with silts and gravels, a shallow water table, and about five feet of non-liquefiable crust. The project faced significant seismic risk, with a design peak ground acceleration of 0.55g and a magnitude 7.4 earthquake scenario.<br /><br />Key challenges included supporting building foundations, limiting settlement to about one inch, and mitigating liquefaction, soil ejecta, and lateral spreading. Deep foundations were considered but would have required very large piles to resist seismic thrust and could not prevent damage from ejecta, making the approach uneconomical.<br /><br />The selected solution was deep-soil-mixing (DSM): soil and cementitious materials were mixed to form a grid of stronger, non-liquefiable soil blocks. The grid transfers building loads toward bedrock, confines the native soil to reduce liquefaction effects, and mobilizes the soil mass beneath the foundations to resist lateral spreading. Global stability and seismic performance were evaluated using PLAXIS and nonlinear dynamic models in OpenSees. The DSM grid was constructed using a triple-auger mixer.

Keywords

Victory Village

Fairfax California

deep-soil-mixing

liquefaction mitigation

seismic risk

soil stabilization

foundation design

lateral spreading

PLAXIS

OpenSees