Determination Of Characteristic Values Of Soil Properties Using Bayesian Theory-Analytical Solution And Software Development

In order to consider the influences of uncertainty of soil properties in geotechnical design,several probability-based codes(e.g.,the Eurocode 7 in Europe,the Geocode 21 in Japan)have been developed and implemented around the world recently.Distribution and characteristic values(mean,standard deviation,quantile)of soil properties are needed in those design codes.However,it is difficult to obtain enough samples of soil property because of limited soil property data during site investigation.This pose a challenge in determining the distribution and characteristic values of soil properties.Bayesian theory provide a way for determining them under limited measure data.However,Bayesian theory is more complicated than traditional statistic method which limits the application of Bayesian theory.This paper deduces the analytical solution of characteristic values of soil properties which improves the efficiency of determining the characteristic values of soil properties in simple condition.In complicated situation,Windows application WHUGSSPA and Android application BEST are developed for engineers to use,those two applications promote the application of Bayesian equivalent samples method in geotechnical design.Firstly,the background,meaning,purposes contents and research status of this paper are introduced.Secondly,Bayesian equivalent samples method is proposed,which includes:uncertainty and probability model of soil properties,Bayesian theory,Markov Chain Monte Carlo Simulation.Thirdly,the analytical solution of characteristic values are deduced.At last,WHUGSSPA and BEST are developed.Main conclusions of this paper are as follows:(1)The proposed Bayesian equivalent samples method is suitable and accurate for different soil properties,in-situ test data and transformation models.(2)The analytical solution of characteristic values of soil properties is deduced and validated,which make the determination of those characteristic values in simple situation more convenient.(3)The developed computer software WHUGSSPA and mobile application BEST make the propose method more distinct.And this provide an effective tool for engineers to determinate those characteristic values and facilitates the application of the propose method.(4)According to the results from illustrative examples,the accuracy and practicability of proposed method,WHUGSSPA and BEST are validated.