17:15 〜 18:45
[HDS08-P09] Frictional property of clay-rich soils as one of geological factors in landslide
キーワード：friction 、clay minerals 、plasticity index
Due to the recent acceleration of the global warming, the impact of landslides as disasters has been increasing. Identifying hazardous areas based on geological factors becomes crucial. Although efforts have been made to identify plausible geological factors characterizing potential areas for hazardous landslide generation, such as strata, rock types and ages, alteration and weathering (e.g., Kawabata and Bandibas, 2009, Geomorphology), citing only several factors would be limited due to the complex intercorrelation among them (Miyachi et al., 2024, JpGU).
We, the Geological Survey of Japan, AIST, have been conducting a research project to integrate geological information for future use in landslide risk assessment since FY2022. In this project, we are investigating frictional properties of clay-rich soils, aiming to evaluate the strength and stability for sliding of each clay mineral. Samples we plan to use are from sites in several landslide-prone areas in Kumamoto Pref., Japan, located on western part of Aso caldera, which are products of geothermal alteration of volcanic ash or lava.
XRD analysis revealed that the samples contained smectite, kaolin minerals (kaolinite and possibly halloysite), alunite, amorphous silica and glass. We also measured plastic limit (WP), liquid limit (WL) and plasticity index (IP = WL-WP) for each sample and plotted the data on a plasticity chart (IP-WL graph). The data on the plasticity chart were distributed along a line of the A-line (Bardet, 1997 Experimental Soil Mechanics), showing an increment of IP in the order of glassy sample, kaolin-rich samples and smectite-rich samples.
We plan to conduct rotary shear experiments on those samples with changing sliding velocity under <1 MPa in normal stress and room-temperature condition. We aim to present the results of our experiments at JpGU Meeting 2024.
We, the Geological Survey of Japan, AIST, have been conducting a research project to integrate geological information for future use in landslide risk assessment since FY2022. In this project, we are investigating frictional properties of clay-rich soils, aiming to evaluate the strength and stability for sliding of each clay mineral. Samples we plan to use are from sites in several landslide-prone areas in Kumamoto Pref., Japan, located on western part of Aso caldera, which are products of geothermal alteration of volcanic ash or lava.
XRD analysis revealed that the samples contained smectite, kaolin minerals (kaolinite and possibly halloysite), alunite, amorphous silica and glass. We also measured plastic limit (WP), liquid limit (WL) and plasticity index (IP = WL-WP) for each sample and plotted the data on a plasticity chart (IP-WL graph). The data on the plasticity chart were distributed along a line of the A-line (Bardet, 1997 Experimental Soil Mechanics), showing an increment of IP in the order of glassy sample, kaolin-rich samples and smectite-rich samples.
We plan to conduct rotary shear experiments on those samples with changing sliding velocity under <1 MPa in normal stress and room-temperature condition. We aim to present the results of our experiments at JpGU Meeting 2024.