Abstract: This paper presents briefly part of the field test fill results of the representative naturally-mixed and artificially-mixed weathered materials at longtan hydroelectric project site. Analysis of the mechanical properties, in particular the strength properties of the weathered materials shows that the weathered materials, whose mechanical properties satisfy the requirements for high embankment dams, belong to the type of gravel soil. It is recommended to use an exponential equation to express the shear strength and the parameters of the exponential equation may be transformed into c and values in the stability analysis.