Long-term effect of potassium chloride treatment on improving the soil behavior of highly sensitive clay — Ulvensplitten, Norway

Abstract

Re-establishing high salt concentration in leached low-saline, highly sensitive clays significantly improves their mechanical properties. Long-term effects on quick clay exposed to diffusion of potassium chloride (KCl) from salt wells installed in 1972 at Ulvensplitten, Oslo, Norway, are investigated. The increased undrained and remolded shear strengths, as well as increased Atterberg limits, remain 30 to 40 years later. The undisturbed shear strength increased from less than 10 to 25–30 kPa, and the remolded shear strength increased from less than 0.5 to more than 6 kPa. The liquid limit increased beyond the natural water content. Adding KCl to quick clay improved the properties to such an extent that it no longer appears as quick. Recent ground investigations in the area suggest a permanent effect on an engineering time scale. Consequently, the method may be suitable to prevent large flow slides in quick clay areas.