DEGRADATION AND MASS LOSS OF JAPANESE CEDAR CYLINDRICAL PILES BURIED FOR 10 YEARS WITH THEIR HEADS AT THE GROUND SURFACE

抄録

 Timber piles for ground improvement have many potential applications, and increasing carbon storage by expanding their usage is expected to contribute to net-zero greenhouse gas emissions by 2050. For this contribution to be reported by the Government of Japan, the rate of mass loss of underground wood must be estimated quantitatively; however, the rate of mass loss is currently unknown. In this paper, a study was performed of Japanese cedar cylindrical piles that were excavated after being buried with their heads at the ground surface for about 10 years in the Inashiki plateau, Japan. The rate of mass loss was analyzed, assuming that no wood decay occurred at depths below the lower limit of the groundwater level. The part of the piles in the range of groundwater fluctuation did not have recognizable mass loss. However, at depths above the upper limit of the groundwater level, the half-life of the mass loss of the parts of the piles where the outer peripheral shape remained was about 50 years, and that of the parts with cross-sectional loss was less than about 10 years.