Consolidation of dredged clays with a system of horizontal and vertical drains is considered. Horizontal drains in the system are made of sand layers, while vertical drains are plastic vertical drains (PVD). Laboratory model tests are performed to study the rapid consolidation behavior of layered clay-sand and clay with PVD. Special cares are given to settlement and the drainage rate of dredged clays with radial and vertical drain system. Numerical analysis is also used to identify the stability time of consolidation, and to verify which method is better suitable for handling large-scale dredged clays.