Experimental and analytical models on laterally loaded rigid monopiles with hardening p-y curves
Short rigid large-diameter monopiles have been widely used for offshore wind turbines. The rotation of the piles is strictly controlled to render safe operation of the wind turbines. Consequently, the determination of the bearing capacity within an allowable angular rotation of the monopiles is an important issue. In this study, six lateral loading tests (at 1 g) were conducted on a rigid model pile in low liquid limit silt (ML) soil (with two relative densities). The tests reveal a rotational center at a depth of (0:75-0:85)L (L = embedded length of the pile) and work-hardening load-displacement curves (a continual increase in soil pressures even at a very large rotational angle). The test results were used to establish new p-y curves using a coefficient of subgrade reaction nh that is correlated to the local pile displacement. In particular, an analytical expression is developed to estimate the net lateral soil resistance p on a circular pile using peak-onpile radial stress. The new p-y curves and analytical solutions capture the measured p-y curves and the load-displacement relationship of the monopiles in cohesionless soils.