PARIKH provided geotechnical engineering services for the project which extended the Caltrain tunnel, now terminating at the center platform of the Santa Clara Caltrain Station. The extension runs underneath the tracks of Union Pacific Railroad and includes a 200-foot-long ramp at the east end, connecting pedestrians and bicyclists from Brokaw Road to Railroad Avenue. The undercrossing extension is constructed with the cut and cover method, requiring a temporary shoefly to maintain the existing rail operations.
Protecting the portal opening to the undercrossing from inundation during a major flood event was a challenging consideration. The solution involved an elevated ramp entry area at Brokaw Road, above anticipated flood levels, allowing storm water to be released through overland flows without flooding the tunnel.
PARIKH conducted geotechnical investigations during preliminary and design phases. Design recommendations were provided for subgrade improvements along the tunnel using geotextile reinforcements, with considerations for railroad surcharges, shoring, and dewatering. This project received the 2018 ACEC GOLDEN STATE AWARD and 2018 APWA Project of the Year Award.