A Numerical Approach to Cyclic Consolidation of Saturated Clays

Abstract

A finite-difference numerical code is written in MATLAB to predict excess pore pressures and settlements under stepped/square wave cyclic loads. The numerical code is developed by approximating the Terzaghi's 1D consolidation equation under time dependent loading using the Crank Nicolson scheme. A method of applying the stepped/square wave cyclic loads is proposed. The code considers the nonlinear inelastic stress ~ strain relationship and can be used for both homogeneous and heterogeneous layers. The code is validated by comparing the results with analytical, experimental, and field monitoring data in the literature. A good agreement of the results shows that the code is well developed and can be used in predicting the settlements in practice. The analyses show that the maximum steady state degree of consolidation calculated based on settlement and the maximum steady-state average degree of consolidation calculated based on dissipation of excess pore pressures decrease as the time period decreases. Below a specific time period, both remain unchanged. For a specific time period, both increase as the percentage of loaded portion in a cycle increases. Besides, the maximum steady-state degree of consolidation based on settlement, for a specific time period, increases with an increase in stress levels, which is due to the nonlinear stress ~strain behavior.