Prediction of the shear deformation of a sandy model slope generated by rainfall based on the monitoring of the shear strain and the pore pressure in the slope

Abstract

It is important to predict shear deformation of a slope due to rainfall infiltration as the basis of the time prediction of an onset of a rainfall-induced landslide. Monitoring of deformations and soil-water conditions in a sandy model slope under artificial rainfall was performed to establish the prediction method for shear deformation of the slope due to rainfall infiltration. A prediction method for the relationship between shear strain and pore pressure was proposed based on the hyperbolic relationship between shear strain and pore pressure measured in the slope. Shear strain is predicted as a function of time before the failure of the slope based on the regression analyses of the shear strain – pore pressure relationship and the time - pore pressure relationship. Prediction of the shear strain using data until a later time could better simulate the measured values. The predicted shear strain in the deeper layer fit the measured values better than that in the shallower layer. A prediction method for the time - surface displacement relationship was also proposed. The procedure for the prediction is the same as that for the prediction of the shear strain, except the surface displacement and the groundwater level replace the shear strain and the pore pressure, respectively, in the procedure. The prediction with data even at an early stage of the experiment could simulate the time variation of the surface displacement well. The proposed prediction method for the surface displacement produced better simulation results than the prediction method for the shear strain.