Analytical analysis of load-transfer of single pile in expansive soil

The derivation of analytic solution to load-transfer for single pile in expansive soil under its swelling was carried out by the shear-deformation method and superposition principle.The corresponding grogram was then compiled to analyze the various factors that affect the pile behavior in expansive soils.The analyzing result show as follows: with the increase of the pile length,upward pile movement could decrease greatly,but meanwhile,tensile force of pile shaft increase as well;the increases of small piles diameter(d0.044 L) can effectively reduce the upward pile movements in expansive soils while those piles with the diameter over 0.044 L contribute little to reducing the upward pile movement;increasing the loads on pile-top can decrease the upward pile movements and tensile forces;the ratio between the load on pile-top that prevents upward pile movement and the maximum axial force of unloaded pile equals 2.5.The study provides theoretical bases for reasonable pile designing in expansive soils