The railroad was constructed along the base of the coastal bluff in the early 1900s and a residential development was constructed at the top of the bluff in the late 1960s. Both the railroad and the residential development were built on top of an ancient landslide. The landslide was remobilised in 2021, damaging several homes and moving the railroad tracks more than 2 feet laterally. Temporary stabilization of the railroad was installed immediately by placing 11,500 tons of riprap at the toe of the slope, and the tracks were realigned; however, the landslide started moving again in the fall of 2022 and passenger rail service was halted to allow for a more permanent repair.
ENGEO and Condon Johnson were engaged to design and construct a system to stop the landslide from additional lateral movement, to protect the railroad tracks, and to get the commuter train back up and running as quickly as possible. ENGEO provided a full geotechnical and civil design and prepared the civil construction drawings for a tied-back grade beam stabilization system.
Grade beam and tie-back retaining solution and temporary construction shoring design. The construction of our design allowed passenger rail service to reopen on February 4, 2023.