Abstract
The increasing costs of design and construction to combat the effects of liquefaction caused by major earthquakes are often considered, as conventional methods of evaluating the strength ratio suggest that the probability of liquefaction is high. The results given are not representative, and evaluation is made on the safe side in diluvial soil. We therefore carried out a systemized investigation into soil quality to understand the strength ratio that causes liquefaction in diluvial soil. The results confirmed that cementation was present in older sedimentation areas, and that the large amounts of fine-grained soil found there provided around twice the strength of alluvion soil. In addition, we suggest a design method based on these results. In diluvial soil, improvements in the rationality and economy of designing and building structures against liquefaction, as well as liquefaction countermeasures, have been made possible thanks to the increased precision of evaluating liquefaction.
