Title

Existing Mitigations of Coastal Landslides at Beverly Beach, Along U.S. 101

Date

5-30-2013 11:00 AM

Location

Health and Wellness Center (HWC) Room 105

Department

Earth Science

Session Chair

Jeff Myers

Session Title

Earth Science Senior Seminar Research: Geological Hazards Impacting US 101 at Beverly Beach, Oregon, and their Mitigation

Faculty Sponsor(s)

Jeff Myers

Presentation Type

Presentation

Abstract

A slumping stretch of roadway along U.S. 101 near Beverly Beach, Oregon, poses safety concerns controllable by mitigations. Siltstone and sandstone of the Astoria Formation, overlain by marine terrace deposits, increase potential landslides throughout the year when rainfall increases pore-pressure between sediments. Short-term fixes involving frequent re-paving and installation of culverts and bridges has allowed the highway to remain in service. Dewatering strategies such as horizontal drains and vertical or inclined wells have successfully lowered pore-pressure, stabilizing slopes in coastal Oregon. This study examines landslides in this region to determine if dewatering is an effective strategy for a more permanent solution. Assessing dewatering concerns including wave erosion, groundwater conditions, and potential for affecting adjacent properties are used to expand options for the most environmentally sustainable and economically feasible solution. Decisions on future remediations are critical to the safe conditions expected of highly trafficked areas such as U.S. 101.

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May 30th, 11:00 AM

Existing Mitigations of Coastal Landslides at Beverly Beach, Along U.S. 101

Health and Wellness Center (HWC) Room 105

A slumping stretch of roadway along U.S. 101 near Beverly Beach, Oregon, poses safety concerns controllable by mitigations. Siltstone and sandstone of the Astoria Formation, overlain by marine terrace deposits, increase potential landslides throughout the year when rainfall increases pore-pressure between sediments. Short-term fixes involving frequent re-paving and installation of culverts and bridges has allowed the highway to remain in service. Dewatering strategies such as horizontal drains and vertical or inclined wells have successfully lowered pore-pressure, stabilizing slopes in coastal Oregon. This study examines landslides in this region to determine if dewatering is an effective strategy for a more permanent solution. Assessing dewatering concerns including wave erosion, groundwater conditions, and potential for affecting adjacent properties are used to expand options for the most environmentally sustainable and economically feasible solution. Decisions on future remediations are critical to the safe conditions expected of highly trafficked areas such as U.S. 101.