Journal of the Japan Society of Erosion Control Engineering, Vol.59,No.6,2007
Predictive equation of unit weights, shear|strength parameters and permeability
of grus
using by simplified dynamic cone penetrometer hardness and grain size
Tsuyoshi Wakatsuki, Yoshinori Sasaki, Yukiya Tanaka and Yukinori Matsukura
Abstract
A simplified dynamic cone penetrometer is a useful apparatus for the measurement
of the hardness of slope materials at many points and depths of the soil layer
on steep mountains. Therefore, some physical and mechanical properties of soils,
such as the unit weight and the shear strength parameter whose measurement generally
needs much time and effort, were estimated by the simplified dynamic cone penetrometer
hardness (Nc) in many previous works. However, the estimated values often change
depending on grains size reflecting lithology. In the present study, based on
the results of field measurement of physical and mechanical properties of hillslope
materials in six granitic mountains, we deduced the dry unit weight of grus (d,
gf^cmR) and the angle of internal friction (sat, degree), the cohesion (csat,
gf^cmQ) and the hydraulic conductivity (K, cm^sec) of grus under saturated water
content from two parameters of Nc]value and grain size of soil as following regression
equations:
dPDQQWNcODPRTCCQDO@ODPOQ
satPDRVVNcCCODT{QUDUP
csatSDOSXNc|SUDVOCCODOUQT{VPDPR
logPOK|ODUPUlogPONcCCQDO@@|ODPPT|PDWVQCCQDO@@|ODPPT
where CCD is the content for coarser grains than D mm. The values of CCODOUQT,
CCODT and CCQDO can be easily measured by sieving method, so that these parameters
can be easily estimated using the above equations.
Key words:landslide dam, outbreak, Takaiso]yama, erosion, sediment transport,
debris flow, simulatio
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