Estimation of the coefficient of permeability in deep sedimentary ground

抄録

Since 1996, pore water pressures have been continuously measured every 10 min at depths of 80 m (GL-80 m), 402 m (GL-402 m) and 403 m (GL-403 m) on the Tsudanuma campus of the Chiba Institute of Technology in Narashino, Japan. For a long period during the measurements, the periodic behaviour of pore water pressures in the span of a year was such that pore water pressures tended to become low in summer and high in winter. Furthermore, pore water pressures were greatly affected by groundwater withdrawal by some cities in the vicinity of the field site. In this study, the permeability in deep sedimentary ground was predicted using two main methods: The Theis and Jacob methods based on the aquifer test theory and Creager’s and Hazen’s empirical equations. For the Theis and Jacob methods, pore water pressure data at the field site and groundwater withdrawal data for some cities surrounding the field site were employed to predict the coefficient of permeability k. For Creager’s and Hazen’s empirical equations, the values of k were calculated using the grain size analysis results of 37 soil samples collected at a field site. The results obtained from these methods were examined for their applicability to the prediction of permeability in deep sedimentary ground.