再活動地すべり地粘性土のせん断強度

Abstract

ここでは日本で起きた 2 種類の再活動地すべりの研究結果を示す。対応策の設計および地すべり活動の阻止のため、現地および実験室にて調査を行った。得られた結果より、すべり面の残留強度が地すべり活動に大きく寄与することが示され、土の残留強度時における粘土含有率や粘土鉱物について研究した。これにより、粘土含有率の増加はモンモリロナイト含有時と同様に、残留強度を十分に減少させることが示された

This article presents the results of two case studies of reactivated landslides which occurred in Japan. Field and laboratory investigations, including a series of drained ring-shear tests, were conducted in order to design a set of countermeasures and prevent further landslide movement. The obtained results indicated that residual shear strength of soil from the sliding surface contributed greatly to the behavior of landslide; and for this reason, a special effort was made to study the effect of clay content and clay mineralogy on the residual shear strength of soils. It was found that an increase in clay content as well as the presence of montmorillonite significantly reduced residual shear strength.