Improvement of resistance value in simple penetration tests using a variable
impact weight
Naomasa HONDA, Takenobu OKUMURA and Yasuyuki TADA
Abstract
This paper proposes a new type of impact weight for simple penetration tests that
is variable from 1] to 5]kgf in 1]kgf increments. Many simple penetration tests
were conducted to estimate the effect of this weight in three actual forests.
Experimental results provide a detailed description of the vertical distribution
of penetration resistance values within the surface soil layer by using 2] and
3]kgf weights, which are lighter than conventional ones, i.e., 5]kgf. The ratio
of penetration resistance values by using impact weights 5]kgf, 3]kgf, and 2]kgf,
i.e., N5kgf :N3kgf :N2kgf , is nearly equal to 1.00:2.02:3.66. In addition, N3kgf
nearly equals the resistance value obtained with Hasegawa's soil penetration test.
These results show that variable impact weight is very useful for accurately estimating
the physical characteristics of soil within forest slope where hillside collapse
is liable to occur.