Mechanical Properties of Geomaterial Recovered from Disaster Debris after the 2011 Earthquake

摘要

Approximately 20,000 Gg of disaster debris was generated through the 2011 off Pacific coast of Tohoku earthquake and subsequent tsunami. Treatment of the disaster debris is a big challenging geotechnical issue, since a significant fraction of the disaster debris was occupied by soil and tsunami deposit. Recovery and utilization of these soil fractions have been promoted in reconstruction works at affected areas. Although several methods have been developed and employed to recover the soil fractions from disaster debris, small pieces of wood and waste remain in recovered soil. In this research, compaction and strength characteristics of recovered soil was evaluated in terms of the effects of wood contents and size on soil properties. Standard Proctor test was conducted to evaluate the compaction characteristics of the recovered soils, whereas unconfined compressive strength was determined by unconfined compression test. In addition, ignition loss test was done to determine the wood contents in the samples. Experimental results indicate that trend of both maximum dry density and unconfined compressive strength decreased with the increasing wood content. However, three wood combinations (based on size of the wood fractions) for each sample presented similar maximum dry density and compressive strength. Despite this, dry density and compressive strength values were relatively higher for larger size combination. Besides, ignition loss values at 330 °C increased with increasing wood content in the samples. It can be concluded that mechanical properties of recovered soil is influenced by both wood contents as well as size of the wood fractions.