PDR法是计算沉降控制复合桩基的一种经验方法，它在一定程度上考虑了桩的非线性和桩—土—筏的共同作用。

Poulos-Davis-Randolph (PDR) Method is a empirical calculation method. It is easy to compute the relation between the number of piles and the average settlement of the foundation.

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结果表明：采用修正实体深基础分层总和法计算沉降控制复合桩基基础的沉降量要比天然地基浅基础的沉降量小；

The results show that the foundation settlements obtained by the modified deep foundation layer-wise summation method are much less than those of shallow natural foundation.

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和桩基相比，复合地基一般沉降过大，若不能合理控制沉降量，易使上部结构产生裂缝或倾斜。

Compared with pile foundation, settlement of composite foundation is much greater and easily to produce crack or incline in upper structure.

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