刚性桩复合地基垫层合理厚度确定方法

垫层厚度的设计是复合地基承载力能否全部发挥的关键因素，垫层的合理厚度基本是靠经验取值，缺少理论根据。基于垫层-桩-土相互作用机制，考虑使复合地基中桩和桩间土承载力发挥度相等的情况下，给出了垫层合理厚度的计算方法。利用该方法可对刚性桩复合地基进行优化设计。分析表明可以通过调整垫层厚度来调节桩-土应力比，较好地发挥桩和土的承载力，达到降低工程造价的目的。

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.