Abstract
In this paper the author investigates the effects on the ground level in the low land peat soils, which are generally in the Tohoku District in Japan, by variations in the ground water level. In the experiment, two procedures are used. One is a laboratory test on the settling and deformation by water level control and load test. The other is a field test with the settling and observation of the ground water table.
The results obtained are summarized as follows:
1) The settling phenomenon consists of two parts: shrinkage and consolidation by lost of buoyant force.
2) The settling curves decrease very steeply at first. However, after a certain amount of time the curves begin to decrease slowly. The reason why these phenomena occur is discussed detail.
3) It is found that sharing parts of consolidation in the total settling are rather small, after the calculating results of consolidation settling.
4) In the field test, the top layer is sensitive to variations in the water level, while the sublayer does not show.
5) The total settling of the peat soil layer can be analyzed assuming four layers: the first layer above the water table, the second layer affected by variations in the water level, the third layer affected by consolidation below the water table, and fourth layer not affected by consolidation below the water table.
