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.