SDE was contacted to assist in a critical emergency project identified by the City of San Diego in August 2019. The city undertook the $3.2 million emergency project in August to reinforce a section of Coast Boulevard above a sea cave known as Koch’s Cave that was collapsing. SDE was tasked to provide land surveying services in support of the design of the new road surface, storm drain replacement, and road stabilization. The information was provided to the designers expeditiously in order for them to fix the problem. The project was designed and completed in October 2019.

In order to stabilize the roadway above an existing sea cave, contractors first injected a polymer-based grout below the street into the surrounding ground to permeate and stabilize the soil. Following this, crews will create a barrier at the mouth of the cave and drill access points through the street.  Next, the contractor will fill the cave with a concrete slurry to stabilize the road above the cave and surrounding area. Once the major underground stabilization work is finished, the concrete roadways and sidewalks impacted by construction were replaced.

SDE services included locating existing horizontal & vertical project control, deployed a drone to capture aerial topographic mapping and color digital orthophotography, terrestrial topographic mapping, and construction staking for road surface and storm drain replacement, as needed.  The survey had to be completed in a short amount of time, and deploying a drone enabled us to quickly capture the existing conditions of the road surface.  We worked closely with the city survey department to ensure work was performed accurately, efficiently, and in compliance with city standards.  We were able to provide construction staking data to replace the road surface to the pre-existing conditions, including traffic, bike, parking striping, and the installation of a new upgraded storm drain system.

Read more about this project here.