BIG SUR – Caltrans’ work at Regent’s Slide, where Highway 1 along the Big Sur Coast remains closed, has shifted focus to installing shear dowels to limit further slide activity.
Regent’s Slide — post mile 27.8 — occurred March 9, 2024, and started seeing top-down removal of slide material by crews on April 30, 2024. The slide originated 450 feet above the roadway, displacing material that engulfed Highway 1 and continuing down to the beach and ocean below.
RELATED: Caltrans using remote-controlled equipment to help clear Highway 1 slide near Big Sur
Caltrans introduced remote-controlled equipment for use at Regent’s Slide in mid-March allowing operators to take more risk than they would with dozers and excavators that had people on board. It since has gained improved excavation productivity with the use of traditional and remote-controlled heavy equipment, but monitoring devices and field observations identified new slide activity and surface cracking in the slope immediately above the project area.
Crews are currently in the process of installing dozens of shear dowels, steel bars about 60 feet in length into the slope above the work area. The shear dowels are drilled into the slope and grouted in place in a 10 foot by 10 foot grid fashion.
The primary function of shear dowels is to reinforce the slope by increasing its internal shear strength. By anchoring the unstable soil layers to more stable underlying materials, they help resist the forces that can cause landslides. This method is particularly effective in areas where traditional excavation or grading is not feasible due to environmental concerns or terrain challenges.
Shear dowels were previously installed in the slope immediately north of the area now exhibiting movement and have been successful there in limiting further slide activity.
Crews installing the shear dowels are working seven days a week and extended hours, according to Caltrans. It is anticipated that excavation activities will resume using traditional and remote equipment in the upcoming weeks once the shear dowel installation has been completed and monitoring equipment and site conditions indicate that it is once again safe to do so.
In August 2024, continued slide activity in and around the Regent’s Slide repair site on Highway 1 halted excavation work for a time. It forced Caltrans to begin work higher up the slope but as slide activity continues, it has sometimes required workers loading the slide to back off of it as site conditions indicate.
Given the complexities of the site conditions and the priority to complete repairs in a safe and timely manner, Caltrans has engaged an outside professional Geotechnical consulting firm to support the repair effort at Regent’s Slide.
As previously announced, repairs to Regent’s Slide are now expected to keep Highway 1 at this point closed through this summer, but Caltrans says it will continue to provide regular updates on progress on the slide repairs and an estimated reopening date.
Once work at Regent’s Slide is complete, it would open up Highway 1 to direct travel between Carmel and Cambria.
Currently, visitors coming from the north are able to travel to Big Sur, its businesses and surrounding area up to the northern-most closure point at Lime Creek — post mile 32.1 — just south of the Esalen Institute, while travelers from the communities of Cambria, San Simeon and the south coast continue to be within reach from Southern California up to the southern-most closure point at south of Vicente Creek Bridge at post mile 25.3.
There is a 6.8-mile-wide segment of Highway 1 between the two turnaround points that remains inaccessible to through traffic due to the ongoing repair work at Regent’s Slide.
Road information and updates can also be found on Caltrans District 5 Social Media platforms: X/Twitter at: @CaltransD5, Facebook at: Caltrans Central Coast (District 5) and Instagram at: Caltrans_D5.