Study on cyclic loading and unloading characteristics of remolded saturated soft soil

This paper described a continuous load one-dimensional K0 consolidation apparatus developed and improved, conducted an axial cyclic loading and unloading test of saturated soft clay. It can be known from the experimental comparison that during the unloading period, a stress strain curve of saturated soft clay is made hyperbolic. During the reloading period, when the loading quantity is less than the unloading quantity, the curve is hyperbolic, and when the loading quantity is greater than unloading quantity the curve is a straight line which keeps hardening. The plastic deformation and elastic deformation of test samples produced in the test have linear relation with the unloading level. On the basis of the original constitutive relation, axial circulation loading and unloading constitutive equation have been established using the loading axial stresses, initial tangent modulus, maximum unloading axial strain and its initial secant modulus as parameters. The reliability of equations was verified as well. The analysis of various plastic hysteresis reveals that as the unloading stress level increases, the hysteresis increases too and conforms to the quadratic curve relationship. This provides a certain engineering practice value for the strength and deformation characteristics of soft soil under cyclic loading