Abstract: A general relation, expressing changes in averages of slope displacements at different time scales as wavelet transform coefficients corresponding to those scales, is presented through analyzing the integral description of the difference between averages of measured displacement data over two adjacent time intervals in comparison with the wavelet transform equation by using Harr wavelet mother function. On basis of this relation, a method to carry out the multi-scale analysis of displacement evolution for slopes is proposed in which changes in averages of slope displacements over two adjacent time intervals at different time scales can be determined by means of wavelet transform method. The multi-scale characteristics of displacement evolution for the new landslide in Wolongsi slope, the excavation of the permanent ship lock in the Three Gorges Project, and the construction of the intake in Geheyan Hydropower Station, respectively, are discussed by using the measured data of slope deformation. When the developing tendency of slope displacements is relatively regular, their characteristics evolving with time can be draw from the measured data at one time scale level. The influence of strong excavation disturbances up on slope deformation can be approximated by the raising line that links the end of support time interval at a given scale with the time point at which the displacement sharply changes.

Key words: rock and soil mechanics, slope, displacement, multi-scale analysis, wavelet transform