Serving professionals in engineering, environmental,
and groundwater geology since 1957

NOVEMBER MEETING NOTICE
***Wednesday, November 13, 2013***

Topic: "The November 2011 White Point Landslide, Paseo Del Mar, San Pedro, California"

Speaker: Dean G. Francuch, P.G., C.E.G., Associate Geologist
Shannon & Wilson, Inc., Glendale, CA

Location: Cisco's Restaurant
925 S. Westlake Blvd
Westlake Village, CA
(805) 778-1191

Date/Time: Wednesday, November 13, 2013
5:45pm - Social Hour
6:45pm - Dinner
7:45pm - Program

Cost: $30 per person with reservations in advance for AEG members, $35 Non-Members and AEG members without reservations (at the door), $15 for students with a valid student ID.

RSVP: Please email Edmond Lee at: edmond@geoconceptsinc.com
or call (818) 994-8895 ext.103.

Please make reservations by e-mail prior to 10 a.m., Wednesday, November 13th, 2013


Abstract
The November 2011 White Point Landslide, Paseo Del Mar, San Pedro, California.
Presented by: Dean G. Francuch, C.E.G., Shannon & Wilson, 664 West Broadway, Glendale, California 91222

The November 2011 White Point landslide truncated Paseo del Mar, which serves as the main coastal access road between San Pedro and Rancho Palos Verdes. The White Point landslide consisting of a large block of the coastal bluff moved rapidly towards the ocean, destroying a 600-foot-long section of Paseo del Mar and associated utilities. The block moved approximately 60 feet to the south towards the Pacific Ocean within a few minutes. Indications of distress consistent with the limits of the White Point landslide were first noted in January 2010, following a smaller landslide to the southeast in late 2009. Movement of the White Point landslide increased in June 2011 and continued toward the beach over a period of five months leading up to the catastrophic November 20, 2011 failure.

Nine borings were initially completed by Shannon & Wilson around the circumference of the landslide in late 2011, using bucket auger, rotary core, and rotosonic drilling techniques. Bentonite clay beds were observed in several borings near the depth of the inferred landslide failure surface and were highly polished, soft, wet, and discordant with adjacent bedding. Instrumentation consisting of PVC observation wells, inclinometers, and vibrating wire piezometers was also installed in several of the borings. Groundwater levels encountered during drilling and from continued monitoring indicate that the groundwater regime at the site consists of both unconfined and confined zones.

Slope stability analyses were completed of the current landslide and potential future landslides. Back analyses of the pre-landslide conditions were also performed to help determine material strengths and groundwater conditions for forward analyses. Our analyses indicate that the presence of water in rock discontinuities and artesian groundwater pressure acting on the failure surface had the strongest influence on the stability of the slope. The results suggest that precipitation, irrigation, and to a lesser extent, coastal bluff erosion may have contributed to the development of the White Point Landslide. Residential development in the area may have also contributed to the landslide because of its influence on groundwater infiltration.

An initial 170-foot buffer zone extending from the headscarp of the White Point landslide was established unless additional measures were completed to stabilize the remaining slope. Current stabilization measures include dewatering improvements consisting of horizontal directional drains, along with installation of a slope anchor system along the eastern margin of the landslide. Corrective grading of the graben area of the landslide has also been completed to reduce shallow sliding and toppling failures and to promote surface water flow out of the graben.

Six long-term mitigation options were also prepared for the roadway, including: 1) Building cul-de-sacs at either end of the landslide; 2) Re-routing the road around the landslide; 3) Re-grading the landslide debris and adjacent area to restore the road to its previous alignment across the existing landslide; 4) Supporting the road at its previous alignment with a soil buttress; 5) Supporting the road with a retaining wall; or 6) Spanning the landslide with a bridge.
 
Speaker Biography
Over the past 27 years, Mr. Francuch has been actively involved from the "ground up", conducting and managing projects involving geotechnical engineering and engineering geology for engineered facilities (landfills, mines, transportation, and pipelines) and residential developments. Dean's experience includes working on both private and public-funded projects from small single-lot homes to 2000-acre master-planned developments. For many of those projects Dean planned and implemented geologic and geotechnical investigations to characterize soil and rock conditions at the sites. He has conducted numerous geotechnical investigations to recognize active faults, landslides and other geologic hazards common in the western U.S. Dean's professional experience spans the State of California from the southern border to the Cascades, and includes field work within the States of Nevada, Colorado, Montana, and Arizona. He has been actively involved in field studies during his career, having conducted extensive geologic mapping projects throughout southern California within various geologic terrains. He has been intimately involved in drilling projects for landfills, large-scale real estate developments, mining operations, wind farms, and highway projects. He also has a considerable amount of experience with groundwater well installation having worked on groundwater studies for landfills and industrial facilities, gaining valuable knowledge of various drilling techniques and practical well construction methods. Besides his professional geologic background, Dean has an extensive knowledge of freight and passenger railroad operations and holds a "Class 1" Certified Locomotive Engineer license with the Fillmore & Western Railway in Ventura County, California.