簡易貫入試験機の分割型ランマーの試作とその性能評価

抄録

The resistance value in simple penetration tests, i.e., the Nc-value, is useful for investigating sliding surfaces or the surface soil layer of a forest slope. However, the impact weight of 5-kgf, which is the conventional one used in the tests, is too great for accurately estimating the physical characteristics of soil within the surface soil layer when the soil layer is soft. This paper proposes a new type of impact weight for simple penetration tests that is variable from 1-kgf to 5-kgf in 1-kgf increments. Many simple penetration tests are conducted in order to estimate the effect of this weight on an actual forest slope. Experimental results provide a detailed description of the vertical distribution of the penetration resistance value within the surface soil layer. This is made possible by using lighter weights than the conventional one, especially the weights 2-kgf and 3-kgf ones. In addition, the penetration resistance value obtained with the 3-kgf weight is nearly equal to that with Hasegawa 's soil penetration test, but detail is improved further by using the 2-kgf and 1-kgf weights.