A method analyzing deformation of anchor foundations in soft clay under static and cyclic loads

The paper presents a constitutive model to describe undrained cyclic stress-strain responses of soft clays based on the equivalent visco-elastic and creep theories. The hysteretic and nonlinear stress-strain responses of soft clays are described using the equivalent visco-elastic relationship and variations of the cyclic modulus and the damping ratio with the octahedral shear strain, respectively in the model. The cyclic accumulative strain is described using the Mises creeping potential function and the associated flow rule. The method determining the model parameters is given by static and cyclic triaxial tests. The finite element method to analyze deformation of anchor foundation in soft clay under static and cyclic loads is developed based on the model. For the method, a cyclic loading time history is divided into a series of incremental loading sub-processes which include one load cycle at least. The cyclic stress-strain responses of soil elements at any time are not tracked in detail and determined by the equivalent visco-elastic calculations for every loading sub-process. The accumulative deformation of anchor foundations is calculated using the initial strain algorithm. The method has been implemented in ABAQUS Software by developing interface programs. Model tests of the suction anchors are conducted and predicted using the method. Comparisons of predicted and model test results show that the method can be used to evaluate cyclic stability and reveal the failure process and mechanism of anchor foundations by analyzing deformation time-histories.