Abstract: Geotechnical parameters are closely related to the stress environment, sedimentary condition, weathering degree, buried condition and other factors. The statistical data of geotechnical parameters have high space variation and relativity. Sometimes, it is uneconomical to use the noncorrelative statistical parameters in geotechnical engineering analysis and design. The variation law and relevant key factors of geotechnical parameters are researched. The depth or distance from the test point to the bottom or surface of the layer could be correlational with geotechnical parameters. Besides, the criterion and formulas of correlational geotechnical parameters are provided; and the graphical method is used to study the reliability of different calculation methods. Finally, in the two cases of foundation design of conventional island in a certain nuclear power station and the slope desigh of a certain transformer station, the criterion and formulas of correlational geotechnical parameters are applied for optimization design. The correlation analysis shows that the geotechnical parameters varied regularly in the layers should be divided into the correlational type. The depth or distance from the test point to the bottom or surface of the layer could be the correlational parameters; the correlational standard values of geotechnical parameters are more reasonable and economic in geotechnical engineering analysis and design.

Key words: correlational parameters, regression analysis, standard values, reliability, engineering project