In this paper,the relationship between Marshall stability and grading curve trait of asphalt mixture is studied based on mathematical statistic.

It is described in the paper that when the parameter of the original series V vehicle is varied, ideal brake force distribution feature curve (I curve) is used to analyses and optimize different structural parameter Therefore, the brake is designed to meet not only the original design theory but also the requirements of laws and regulation of our countr

Results show that the stability of soils relates closely to the shape of gradation curves and coefficient of ununiformity.

Also,the advantages and disadvantages of semi-logarithm coordinate,constant logarithm coordinate and exponential coordinate are compared,and the exponential coordinate is proved as the optimal form of the gradation curve.

This part II, with respect to filters we indicate that the developing tendency of controlled grain size is one point of average grain size first and then to two points as well as to many points along the grain size grading curve.

On the premise that the grading curves of soil grain are similar to the cure of normal distribution the method to delimiting effective size is presented.

The authors analyzed the grain size of 22 surface sediment samples taken from the adjacent sea area off the Changjiang Estuary,based on these data this paper discusses the grain size fractions distribution characteristics and their significance using the multivariate analysis method and the contrast of different types of areas.