Method for calculating rational thickness of cushion in rigid pile composite ground

In the process of designing rigid pile composite foundation, thickness of cushion is very important. It is one of the most important factors in the bearing capacity. But there is no theoretical method in designing the thickness of cushion. Based on the relation among pile-soil-cushion, a method for calculating rational thickness of cushion in rigid pile composite ground is derived. The optimization design of the rigid pile composite ground can be performed with this method. Analysis shows that adjusting the stress ratio by changing cushion thickness would exert the bearing capacity and reduce the engineering cost.