In preparation for the construction of the six-mile Phase II Extension, VTA needs to know more about the soil and the location for utilities in the path of the future project. This information helps us advance the design and engineering of the BART tunnel, station, and other facilities and avoid project delays once construction begins.
These field investigations started in late September and will continue through the middle of 2019. The subsurface exploration, utility investigations, and geotechnical borings will take place on surface streets, private property, and occasionally on sidewalks as crews work to assess conditions underground. All working areas will be restored and reopened at the end of each working day, and no weekend work is anticipated.
What type of work is being done?
Geotechnical investigations provide important details about the soil underground and involve drilling and extracting soil samples to test. A truck-mounted drilling rig drills small diameter holes about the size of a soda can up to 150 feet deep to extract soil and groundwater samples.
Utility investigations reveal the precise locations of underground utilities such as water, power, communications, and sewer lines, which are typically located less than six feet down from the surface. A truck-mounted, high-powered vacuum safely removes a small amount of soil around each utility. A surveyor notes the exact location and then the small hole is backfilled. The pavement is replaced and the crew moves to the next location.
How will we find out about this work?
VTA staff has been out in the field to inform stakeholders about the work and will continue to do so two weeks and 72 hours before field work begins. You can also see the current construction notices at http://www.vta.org/bart/construction