Devil’s Slide Tunnel Project Nearly Complete

December 27, 2012 rockman Project Related Comments Off

Inside the Devil's Slide tunnel construction, by kxyoung on Flickr

Earth Mechanics Inc. was Lead Geotechnical Engineer on Devil’s Slide Project

I only recently came across a project bio on the website of Earth Mechanics Inc. (EMI) that describes their role as the lead geotechnical engineer for the project. I’ve mentioned geotechnical features in earlier blog posts, but I never saw any reference to EMI or provided them with any credit. Here is a paragraph from their project bio:

Devil’s Slide Tunnels are twin bores in rock, approximately 4,000 ft portal-to-portal, constructed along US Route 1 near Pacifica, California. Earth Mechanics was the lead geotechnical engineer to provide geologic/geotechnical interpretation and design recommendations for the tunnels, portals, soil nail walls and on-site spoil disposal.

EMI carried out a major site investigation program consisting of detailed geologic mapping, aerial photographing, rock borings, and trenching. In addition, pressuremeter testing, seismic velocity logging, video imaging, and hydraulic packer testing were conducted in the boreholes. EMI developed seismic loading criteria for the project by conducting seismic hazard analyses and developing earthquake time histories for design of the tunnels and portals. Various loading mechanisms on the tunnel support systems were examined including geo-static loading, seismic induced distortion of the support system, and key block loading.