Physical properties of the Joso Clay in the Tsukuba Upland from the hydrological point of view

Abstract

The upland is composed of the Younger Kanto Loam (about 3m thick at most), the Joso Formation, and the Kioroshi Formation in descending order. In the upper part of the Joso Formation is a less-permeable clay/silt layer called the Joso Clay. Saturated hydraulic conductivities of the Joso Clay proved to be extremely low, ranging from 8.29 × 10-6 to 5.30 × 10-9 cm/sec with an average value of 1.39 × 10-6 cm/sec. The Joso Clay presented a remarkable contrast in saturated hydraulic conductivity to both the overlying Younger Kanto Loam and the underlying sands, showing differences of two to three and three to five orders of magnitude, respectively. The porosity of the Joso Clay was between 54% and 77%. -from English summary