Study on the effect of roughness interface on friction behavior of cohesive soil and concrete

Abstract

The bearing capacity of friction pile is influenced by characteristic soil and the contact between the surface of the structure on surrounding soil. The surface roughness of the pile will also affect the friction capacity of pile. This research utilized direct shear test on the variant of roughness surface of the concrete-soil. The research used five models variants of concrete surface roughness and two cohesive specimens from west Java are Gedebage and Rancaekek. The model of interface for driven pile on cohesive soil and concrete surface roughness test was conducted using surface roughness test tool with 2.5 cm of contact field and 0.2 mm/second shear rate obtained Ra (ηm) value. To represent roughness Ra is used, the higher surface roughness is the greater the value of Ra. The maximum soil shear stress of Gedebage specimen from direct shear test is 0.914 kg/cm2, while Rancaekek specimen is 0.589 kg/cm2. Both specimens are cohesive soils with high plasticity. According to the value of interface fs = α.Cu with α is the adhesion factor of soil-concrete interface, the result of direct shear test of two samples with the variant of surface roughness value obtained give the greater value of α. And the double wafer surface roughness has the greater value of α. It can be concluded that the variant of concrete roughness surface influences the shear behavior of concrete – soil interface.