bridge pile foundation; geotechnical uniformity; randomness of change; small sample statistics; division of sections; standard values of geotechnical parameters
the determination of geotechnical parameters and standard values of rock strength in the current geotechnical engineering investigation specifications(national standards) and highway specifications has basically absorbed the t-distribution statistical method applicable to small samples. Based on the statistical analysis of the standard values of pile sinking construction and static penetration test of each pier of Donghai Bridge on land, it is shown that in order to ensure the 95% confidence probability of the standard values of geotechnical parameters of each pier and abutment, the small sample statistics should be adopted according to the specifications in the detailed engineering exploration stage. Therefore, for long bridges, such as viaducts, large overpasses, long approach bridges, etc., it is necessary to reasonably divide the sections for statistics according to the change of soil layer and soil homogeneity, while for large bridges, it is necessary to make separate statistics.