Lime remediation of reactivated landslides

Lime improvement of frictional resistance was examined using samples of Brenna Clay Formation from North Dakota. The montmorillonitic stiff clay samples had a natural water content, plastic limit, liquid limit, clay size fraction, fully softened friction angle, and residual friction angle, respectively, in the range of 42 to 85%, 20 to 40%, 62 to 154%, 60 to 95%, 14 to 24°, and 7 to 9°. Immediately after introduction of hydrated lime, pH increased to a range of 12.2 to 12.7; within hours, however, pH began to decrease. Whereas there was a large increase in plastic limit, the liquid limit response to lime treatment was dependent on the effective confining pressure. Lime treatment increased fully softened friction angle by 5 to 10° at effective normal stress of 100 kPa and by 3 to 5° at 300 kPa. Lime treatment increased the residual friction angle by 3 to 6° at both 100 kPa and 300 kPa.