Conduct soil surveys for projects with the following features:

Bridges
Retaining walls
Slopes and embankments
Sign structures
Illumination
Sound walls
Radio towers

Perform minimum required testing for all structures, including Texas Cone Penetration (TCP) testing at 5-ft. intervals and at strata changes, as well as Rock Quality Designation (RQD) and percent recovery in rock. See the remaining portions of this chapter for requirements for all explorations.