桩基不重复随机抽样不合格桩数概率分布研究及其工程应用

RESEARCH ON PROBABILITY DISTRIBUTION OF THE NUMBER OF DEFECTIVE PILES IN TESTING PILE FOUNDATION BY RANDOM SAMPLING WITHOUT REPETITION AND ITS APPLICATION IN ENGINEERING

用条件概率方法研究桩基质量随机抽样不合格桩数ｒ的概率分布ｐ_（ｎ，Ｎ）（ｒ）和数字特征的计算公式。然后，引用计算随机变量函数概率分布的方法，导出桩基抽样不合格率γ的概率分布ｐ_（ｎ，Ｎ）（γ）和数字特征的计算公式。这些公式为桩基质量检测的统计推断提供了理论基础。

In this paper, the conditional probability method is used to derive the formulae of probability distribution and statistic expectation of the number of defective piles in testing the ovens guality of a pile foundation by random sampling without repetition. Subsequently, the probability distribution method of random variable function is used to derive the formulae of probability distribution and statistic expectation of the defective rate of piles in testing the overall quality of a pile foundation. The results of these formulae provide a theoretical basis for statistic inferring in testing the ovelall quality of a pile foundation.