Effect of chemical weathering on liquefaction and post-liquefaction undrained monotonic shear behavior for compacted decomposed granite soil

抄録

Monotonic and cyclic triaxial tests were performed on decomposed granite soil (Masado) sampled from Kagawa Prefecture. The effects of the degree of compaction (Dc) and hydrogen peroxide (H₂O₂) injection on the shearing properties of this soil were considered. The chemical weathering of Masado was simulated by reacting the soil with H₂O₂ to oxidize it. The present study was conducted to understand the effects of soil compressibility and chemical weathering on the monotonic and cyclic undrained shear behaviors of soils. In addition, a series of undrained cyclic triaxial tests, followed by monotonic loading, were conducted on the soil to evaluate the post-liquefaction behavior. The cyclic shear strength of Masado at Dc = 100 % tended to decrease with increasing H₂O₂ injection. For the postliquefaction characteristics of Masado at Dc = 100 %, as liquefaction resistance factor FL decreased, the stiffness in the small-stiffness region declined and strain in the low-stiffness region increased. The behavior after liquefaction was only slightly affected by chemical weathering.