Robertson, T., Moon, V. G., & Lowe, D. J. (2017). Is there a potassium-based solution to sensitive soil slipping within the Bay of Plenty? In G. J. Alexander & C. Y. Chin (Eds.), Proceedings 20th New Zealand Geotechnical Society Symposium (NZGS2017) (pp. 1–8). Napier: New Zealand Geotechnical Society.
Permanent Research Commons link: https://hdl.handle.net/10289/11556
Landslides are common in sensitive, weathered pyroclastic soils in the Bay of Plenty (BOP). The clay mineralogy of these soils is dominated by halloysite, an inactive 1:1 clay mineral. Manipulation of cation content within the pore water of sensitive soils has been shown to improve in situ soil strength in illite-dominated soils in Norway. We present results of laboratory tests on the impact of altering cation status of a sensitive soil from the base of a large landslide at Omokoroa near Tauranga, BOP. Addition of KCl and KOH both reduced the liquid limit of the soil, a negative effect. In contrast, addition of K₂CO₃ caused an increase in the plasticity index of soil pastes. Soaking intact samples in K₂CO₃ for three weeks resulted in a considerable increase in peak stress in effective stress triaxial testing. These early results suggest that mitigation of sensitive soil landslides through increasing peak strength by addition of appropriate salts to the soil profile may be an option for mitigation of landslides in sensitive BOP soils.
New Zealand Geotechnical Society
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