Study On Highway Subgrade Design Parameters Based On Blind Number Theory

The selection of highway subgrade design parameters, whether it is reasonable or not, has the extremely vital significance for highway engineering. Soil's properties show great spatial variation because it's forming is a long and complex historical process. Mechanical performance indexes of rock-soil are influenced by many uncertainty factors, such as the internal complexity of rock-soil, the limited samples, randomness and test error. When analyzing soil test data, experimenters usually take the average as the standard value and give it to designers. However, long term project practice shows that, using the average as the standard value when we have only a few experimental dates has biggish fatalness, and this is always unconformable with practical instance. It indicates that when the data is insufficient, results from the calculation and analysis with the mean value are not reliable. Therefore, the study on highway subgrade design parameters is very necessary.In this paper, blind number theory is applied in the credibility analysis of subgrade design parameters. This method can help us obtain a reasonable representative value interval when we only have small sample, so that designers may select parameters in this interval according to the different engineering requirements. Meanwhile, this interval could also be used as a reasonable interval when calculating non-probabilistic reliability indexes which is based on interval analysis, and this can ensure the reliability of highway project. Finally, this article applies the theory to the analysis and determination of Tang Cao highway subgrade design parameter.