Analysis of Laterally Loaded Single Pile in Cohesionless Soil Considering Nonlinear Soil-Structure Interaction Effects: Fid-Bau Portal

Analysis of Laterally Loaded Single Pile in Cohesionless Soil Considering Nonlinear Soil-Structure Interaction Effects

Mallick, Monirul / Mandal, Kalyan Kumar / Sahu, Ramendu Bikas

Beam on nonlinear Winkler foundation (BNWF) is a simplified and most widely used model for analysis of nonlinear soil-structure interaction problem. In this study a numerical model is developed for laterally loaded single pile using open-source finite element-based code OpenSees. Pile and soil are simulated by displacement-based beam element and nonlinear spring element respectively. p-y curves based on API procedures are used for simulating nonlinear behaviour of soil. Pile tip is considered as floating base constraint. Three types of cohesionless soil based on relative density are considered: loose, medium, and dense sand. The present analysis is validated using the theoretical solution of Reese and Matlock (in Proceedings Eighth Texas Conference on Soil Mechanics and Foundation Engineering, Special Publication No. 29, Bureau of Engineering Research, University of Texas, Austin, TX (1956)). The effects of relative density of cohesionless soil, slenderness ratio (L/D) of pile and fixity of pile head on pile and soil responses are investigated. The results show that the lateral displacement of pile decreases drastically with the increase of relative density of soil. The lateral displacement of long pile for loose and dense sand is reduced by 69.75% and 73.90% respectively when the pile head fixity changes from free to fixed head condition. Also, it is overserved that the maximum bending moment of free head and fixed head long pile is decreased by 41.10% and 45.60% respectively when the soil type changes from loose to dense. The behaviour of pile as short rigid or long flexible, response of pile and soil are highly influenced by slenderness ratio of pile. Pile of L/D less than 10 behaves like short rigid pile and more than 10 behaves like long pile. The negative tip displacement is more for short pile with compared to long pile.