Abstract: Excavation unloading, blasting vibration, rock rheology and rainfall are four main factors which affect the deformation of slope during the construction period. With deep analysis of different factors on the mechanism of slope deformation, a forecasting model of slope deformation based on the deformation mechanism is obtained according to slope displacement monitoring data. The formula of rebound slope deformation is derived under the simplification of the theory of elasticity which is used to calculate excavation unloading component; creeping constitutive equations based on Burgers model is used to calculate rheological component; and blasting component and rainfall component are calculated by using the existing empirical formula; the four deformation components are integrated to form forecasting model of slope deformation based on the deformation mechanism, from which a more scientific and reasonable explanation for the mechanical mechanism of slope deformation is got. The model has been used to conduct statistical regression analysis of monitoring data of the slope at the left bank of JinpingⅠHydropower Station. The results indicate that the proposed model gives a significant regression equation with small forecast errors; compared with traditional statistic models, the statistical multiple correlation coefficients and variance ratio are larger; thus the model has great application value

Key words: slope engineering, slope deformation, monitoring, forecast, excavation unloading