Laboratory investigation of suffusion on dam core glacial till

Sammanfattning: The objective of this study is to provide a better understanding of suffusion characteristics of glacial soils and to present a simple yet reliable assessment procedure for determination of suffusion in the laboratory.Internal erosion by suffusion occurs in the core of an embankment dam when the ability of the soil to resist seepage forces is exceeded and voids are large enough to allow the transport of fine particles through the pores. Soils susceptible to suffusion are described as internally unstable. dams with core of broadly graded glacial moraines (tills) exhibit signs of internal erosion to a larger extent than dams constructed with other types of materials.The Suffusion behavior of glacial soils has been investigated through two different permeameter suffusion test have been employed, small scale permeameter and big scale permeameter. Details of the equipment along with its calibration, testing and sampling procedures are provided.The testing program were performed 9 test with different compaction degree in small scale permeameter and 2 test in big permeameter on internally stable categories of till soil. The categories are defined based on the soil grain size distribution and according to the methods developed by Kenney & Lau and Burenkova.Layers are identified with suffusion if the post-test gradation curve exhibit changes in distribution compared to the initial condition and also the tests revealed that the effect of grain size distribution and relative degree of compaction on the internal erosion susceptibility of glacial till soils at different hydraulic gradients