Abstract: This paper presents a practical and convenient method for investigating the safety against tensile, cracking and shearing failure of earthrock dams. It is proposed for use in the prior stage of preliminary design as well as the construction and operation periods of a dam. Since under these conditions it is only necessary to analyze the safety against failure for certain doubtful portions of the dam without resorting to an overall stress and strain calculation by the finite element method. At the prior stage of preliminary design, with the vertical component of the displacement （i.e. the settlement） of a certain point computed, the other two components are given as the respective products of the vertical component and the empirical"displacement ratios". During the construction and operation periods, the three components of the displacement at a specific point are obtained from the observed data.The principal strains are then computed from displacements by geometric equations and the principal stresses are determined by applying the nonlinear elastic increment equations.Since the stress and strain on the dam surface is one-dimensional, safety against cracking can be examined by the result of uni-axial tensile test. While the stress and strain inside the dam is two-or three-dimensional, Safety against brittle crack is examined by the result of tri-axial cracking test and safety against shearing failure by the result of tri-axial shearing test. An example at the end of the paper illustrates the investigation procedure recommended.