INFLUENCE OF SOIL JOINTS ON PERMEABILITY OF GLACIAL TILL
Field data analysis showed the existence of 3 mutually perpendicular prominent sets of joints. The studied glacial till falls into CL-ML category with up to 5% clay. The spacing and aperture of joints was expressed as open area/m2 of the bluff and was about 40 cm2 / m2. In-situ measured water flow velocity varied from 7x10-2–8.23 cm/s. Lab tests showed that intact till permeability varied from 2x10-8 – 1.60x10 -7 cm/s where the permeability of disintegrated saturated till was within the range of 1.44x10-6 – 3.41x10 -5 cm/s. Permeability of glacial till also proved to be time dependant. In case of seepage, permeability is strongly influenced by till water content and the type of joint infilling material, where aperture is not very significant. In the case of turbulent water flow, field tests indicated that the aperture of joints plays significant role in the overall permeability of glacial till masses.