2025 Volume 51 Issue 1 Pages 7-12
Direct shear tests were conducted on soil specimens, containing three types of exotic herbaceous (KBG, CRF and MF) roots both before and after the ideal periods for vegetation establishment using the sodding method in Tokachi district, Hokkaido. In addition, the study investigated strength parameters ( cohesion c ) and influence of slope direction during the first year. The result showed that ⊿c ( increases of c value ) in soil specimen containing roots using sodding method became large in late September irrespective of construction conditions. Additionally, ⊿c values were constantly high on the north-facing slope regardless of when construction took place. Under these conditions, the growth of leaves, stems and roots was comparatively more robust. These findings contrast with prior studies on the seeding method, which indicated a steady high value of c with prolonged growth periods. In contrast, first-year results from the sodding method showed a distinct trend.
