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MONTHLY DINNER MEETING
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Date: *** Tuesday, April 10th ***
(Joint Meeting with South Coast Geological Society)
Topic: FEASIBILITY OF TUNNELING TO COMPLETE THE 710 FREEWAY FROM INTERSTATE 10 IN ALHAMBRA TO INTERSTATE 210 IN PASADENA

Speaker: Bruce A. Schell, PG, CEG
Location: Stevenís Steak House, 5332 Stevens Place, Commerce, CA
Time: 6:00 p.m.-Social Hour; 7:00 p.m.-Dinner; 7:45 p.m.-Presentation
Cost: $30 per person with reservations (no-shows charged full amount),$35 at the door, $15 for students with a valid Student ID
Reservations: Please call Peter Thams at (805) 644-7976 or email pthams@wcenviro.com

Abstract:
The master plan for the Southern California freeway system calls for extending the 710 freeway from Interstate 10 (San Bernardino Freeway) in Monterey Park, through Alhambra, South Pasadena, and Pasadena to the Foothill (210) and Ventura (134) freeways in Pasadena. The master plan for this connection was drawn up several decades ago. The State (Caltrans) already owns most of the property along an alignment, but some locals have objected citing the negative impacts on traffic, air quality, and historic buildings. Meanwhile, the surface streets in the region are abuzz with the roar of heavy traffic and commonly are clogged in the morning and evening rush hours when local residents try to find a way to work or back home. As a possible alternative to the surface roadway, the Metropolitan Transit Authority is studying the feasibility of closing the gap by constructing a tunnel. No specific plans have been made as to the type of tunnel or to the location of the alignment. The tunnel would be about 4.5 miles long with a possible midpoint exit/entrance in the Huntington Drive area near the Alhambra and South Pasadena border. A likely depth for the tunnel would be on the order of about 100 to 200 feet. The tunnel may consist of two parallel tunnel borings (one for each direction of traffic) with two to four travel lanes each. The approximate diameter of the bores would be about 50 feet. Another alternative might be a double-deck roadway within one tunnel. Recent experience and advances in tunneling technology indicate that such a tunnel could be completed using a tunnel boring machine. To date, investigations for the tunnel include various environmental and socioeconomic studies, and literature studies of the geological, seismological, and geotechnical setting along the alignment. These were followed by a very preliminary subsurface geotechnical investigation which included coreholes and laboratory testing. Although very preliminary, these investigations provide insight into the geology of an area without many previous deep geotechnical borings. The talk will focus on the technical issues of tunneling through the area. The completed investigations and results will be discussed. The challenges for this tunnel venture include 1) tunneling through a wide variety of geological formations such as nonindurated, Quaternary-age, fluvial and fan alluvium; soft and hard, folded, bedded, Tertiary sedimentary rocks; Tertiary volcanics, and Mesozoic-age plutonic rocks; 2) ground water; and 3) earthquake- and fault-rupture design. In particular, the tunnel will go through the Raymond (Hill), York Boulevard, and Eagle Rock faults, as well as many other smaller discontinuities.
 
Speaker:
Bruce A. Schell is a consulting geologist who has been practicing independently since 1988. Prior to that, he was Principal Geoscientist at the Earth Technology Corporation. He is licensed in the state of California as a Professional Geologist (PG) and a Certified Engineering Geologist (CEG). He is the Engineering Geologist on the California State Hospital and Building Safety Board and is Chair of the Instrumentation Committee for installing earthquake ground-motion sensors in California hospitals. Bruceís academic history includes a Bachelor of Science from California State University, Northridge and graduate studies at University of Southern California and California State University, Los Angeles. Mr. Schell's consulting practice involves geological investigations for government agencies, other geotechnical firms, land developers, insurance companies, law firms, and property owners. Typical investigations comprise evaluating geological and seismological hazards such as earthquakes, earthquake probabilities, fault rupture, liquefaction, landslides, hydrology as well as routine site characterization and environmental assessments. His investigations typically employ the disciplines of geomorphology, Quaternary geology, seismology, paleoseismology, rock mechanics, and geophysics.

These investigations have been applied to a wide variety of engineering projects throughout the world such as tunnels, bridges, dams, waste repositories, military facilities, power plants, pipelines, offshore oil platforms, ports, and residential/commercial developments. Mr. Schell's work and research have been published in several scientific journals.


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Core samples from a corehole in South Pasadena. Photo provided by Bruce Schell.
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A geologic cross section thru the Raymond Hill fault showing the approximate profile of tunnel. Image provided by Bruce Schell.