砂黏混合土力学特性及其对单桩水平响应的影响OA

Monopile foundations are widely used in global offshore wind turbine projects.In monopile design,the API and PISA methods are commonly used,although they were specifically developed for pure clay or sand.However,sand-clay mixtures are widely distributed in China's offshore areas,and their mechanical properties strongly depend on sand content.Laboratory tests were performed on speci-mens with sand contents of 0,40%,and 60%.The test program included triaxial undrained compres-sion/extension tests and static/dynamic direct simple shear tests.Results show that undrained shear strength increases with sand content,while the axial strain at 50%peak deviatoric stress decreases.In contrast,dynamic strength decreases with higher sand content.The cyclic contour diagrams character-ized the weakening effect on equivalent shear stress.Finite element simulations,the API method,and the PISA method were used to predict monopile responses under static/cyclic loading.Compared with finite element results,the API method significantly underestimates the horizontal bearing capacity.The PISA method provides reasonable predictions.The monopile's static horizontal bearing capacity increa-ses with sand content.For cyclic loading conditions,however,higher sand content leads to faster degra-dation of bearing capacity with increasing cycle numbers.