DESIGN METHOD FOR DRILLED SHAFTS IN SOFT ARGILLACEOUS ROCK

A simple, rational method for predicting load-movement behavior of axi ally loaded drilled shafts in argillaceous intermediate geomaterials ( hard clays and soft rocks) is presented. The method is based on a para metric finite element study that is described in detail in a companion paper. The method emphasizes the importance of the value of initial c oncrete pressure and roughness of the borehole. A numerical example is presented, and four diverse case histories are summarized that illust rate applications of the method to realistic geological and constructi on situations. Parameters that are included in the method include geom aterial compressive strength and modulus, borehole roughness, borehole smear, concrete pressure in the socket, and angle of sliding friction at the interface. The method is applicable to cohesive intermediate g eomaterials that exhibit drained (c = 0) interface behavior, which can be assumed to be nonporous, argillaceous (clay-based) hard soil and s oft rock.