Consolidation Deformation Characteristics of Hachirogata Clay and Settlement Prediction of Irrigation Structures

Abstract

In this study, based on the soil constants obtained from the soil test results, the settlement of the Hachirogata clay ground were predicted by considering the consolidation theory and secondary consolidation behavior for the pipeline buried structure ground model. The coefficient of volume compressibility, the coefficient of consolidation, and the coefficient of permeability in the normally consolidated region were in the range of 10^-4 to 10^-2 m²/kN, 5 to 400 cm²/d and 10^-9 to 10^-7 cm/s, respectively and the coefficient of secondary consolidation increased as the stress condition approached the normally consolidated region, showed a maximum value of about 0.15, and tended to decrease with the subsequent increase of the pressure. It was found that the degree of consolidation at the start of secondary consolidation is in the range of 60 to 85%, and is particularly concentrated in 60 to 70%. As a result of predicting the settlement of the irrigation structure in consideration of the secondary consolidation, it was suggested that the differential settlement and reverse gradient between the main irrigation channel may occur based on the adopted calculation conditions.