Rancho Palos Verdes Landslide-PPT Presentation

PPT Presentation

Pdf Summary

The Portuguese Bend landslide in Rancho Palos Verdes, California, has been publicly recognized since 1931, with remediation efforts beginning in earnest in 1957. A 1989 study led to increased road-repair budgets and the relocation of some infrastructure above ground.<br /><br />Recent investigations used sonic drilling to collect continuous soil cores to depths of up to 340 feet. The cores improved understanding of the landslide’s geology and refined its structural model, revealing three slide planes rather than the single plane previously assumed. Sonic drilling was selected for its ability to identify clay layers accurately and maintain borehole verticality, helping determine suitable locations for pumping. Investigations also included 15 vibrating-wire piezometers and numerous shape-array inclinometers; some inclinometers were sheared off within days.<br /><br />To slow the landslide, 11 dewatering and depressurization wells, up to 200 feet deep, were installed and operated. These wells significantly reduced the rate of movement. The presentation also notes California’s use of Geologic Hazard Abatement Districts to address geological hazards.

Keywords

Portuguese Bend landslide

Rancho Palos Verdes

California

sonic drilling

soil cores

slide planes

dewatering wells

depressurization

vibrating-wire piezometers

Geologic Hazard Abatement Districts