Abstract: The pile foundation in high-steep rock slope has double functions, i.e., transferring loads from superstructure and bearing landslide thrust, and the mechanical behavior is very complex. In order to reduce the adverse effect of the pile friction to the slope stability, a steel casing coating pile (SCCP) is proposed, in which the isolation steel casing is set outside of the pile, and the inner of steel casing is coated by the asphalt. Based on the push-out test, the lateral friction distribution rule of pile and the isolation resistance-reducing effect of the asphalt coating are studied. The experimental results indicate that the shear stress of the concrete without asphalt coating is large at both ends and small in the middle, and the asphalt coating can effectively reduce the lateral friction of the pile, change the bonding mechanism between steel and concrete, and make upper loads transferred to deep rock mass. Based on numerical analysis, it is shown that the steel casing coating pile can reduce the upper friction of pile, and transfer the load to deep rock mass, and lessen the adverse effect of the pile lateral friction above the slope sliding surface to the stability of the high-steep slope.

Key words: high-steep slope, pile foundation, steel casing, asphalt coating, push-out test