To examine the influence of strengthening effect of skin resistance on the bearing mechanism of laterally loaded pile

this study firstly established τ-s curve models with consideration of strengthening effect under horizontal loading. Then its numerical solution for resisting moment per unit length caused by vertical shaft resistance was obtained. This work performed the analysis on normalized curves with form of Ms

ini /Msu

ini-θ/θref

ini under the influence factors including pile diameter

critical displacement and limit shaft resistance. Accordingly

based on the theory of strengthening effect of skin resistance

this paper deduced simplified theoretical solutions of resisting moment for τ-s curves with linear elastoplastic type

hyperbolic type

clay and sand type of API Code

respectively. Moreover

combined with the principle of transfer matrix method

this work obtained the semi-analytical solutions for laterally loaded pile considering resisting moment effect. The results from proposed calculation models compare well with validation cases

which verify the reliability of simplified solution of side friction caused resisting moment and of proposed pile responses considering resisting moment effect. The comparisons also indicate that the influence of strengthening effect of skin resistance on bearing capacity of laterally loaded pile is non-negligible. Finally

the results reveal that in case of no test data for reference

the recommend values of rigidity indexes for interfaces of sand-pile and clay-pile could be 0.725 and 0.600

respectively. This resisting moment effect will increase as pile diameter

ultimate shaft resistance increases or increase as critical displacement decreases

while pile diameter has more notable influence.