砂井地基固结的概率设计

将概率统计理论引入砂井地基固结问题的分析中，克服了现行“确定性”分析和设计法的不足。对砂井地基固结的概率分析进行了系统全面地研究，提出了砂井地基固结概率设计的设计系数法。该法用设计系数将砂井地基的固结概率设计与常规设计联系起来。径向固结系数的设计值等于其标准值与设计系数的乘积，也等于其均值与中心设计系数乘积。推导了径向固结系数为对数正态分布和伽玛分布时设计系数的计算公式，并据此研究了设计系数的变化规律。中心设计系数是径向固结系数变异系数的减函数，而是失效概率的增函数。研究了径向固结系数标准值的计算方法。为便于工程查用，提供了设计系数图表。提出了砂井地基固结概率设计的一般步骤，并用算例说明了该法在实际工程中的应用。

Probability design of consolidation of sand-drained ground

On the basis of probability and statistics theory, a systematic study is carried out on the probability design of consolidation of sand-drained ground, which overcomes the shortage of the current determination method of design. The probability design method the design coefficient method, is proposed, that is correlated with the conventional design by the mean of design coefficient. The design value of horizontal coefficient of consolidation can be made by multiplying its standard value and design coefficient or by multiplying its mean and central design coefficient. Under the conditions of the horizontal coefficient of consolidation being either a log normal distribution or a gamma distribution, the formulas for computing design coefficient are derived. According to these formulas, the variation of design coefficient is studied. The central design coefficient is decreasing function of coefficient of variation of horizontal coefficient of consolidation, and increasing function of probability of failure. The method of calculation on standard value of horizontal coefficient of consolidation is discussed. The tables and diagrams are given, which can be used to look up the coefficient of consolidation. A probability design procedure for consolidation of sand-drained ground is established; and its practical application is illustrated by example.