地すべり地における地下水・地表水 (第三報)

深さ別の地下水位・水圧変動現象の研究

抄録

The fluctuation phenomena of ground water level and pressure were observed with two types of piezometer (quasi-Cassagrande type and electrical diaphragm type) installed at various depths (1-15m) at Naguki landslide area, Nagano Prefecture.
The fluctuations recorded by each piezometer can be divided into two elements-trends and short periodic fluctuations discussed in this report-by the arithmetic moving average method. All periodic fluctuations are classified into the fluctuation caused by precipitation and the fluctuation caused by atmospheric changes. It is assumed that the former is a property of ground water flow through large pores and cracks of the landslide soils and that the latter is a property of soil water in the aquiclude consisting of elastic landslide soil.
The ratio of pore pressure caused by atmospheric changes in the elastic aquiclude to atmospheric changes, elastic moduli of the soils, effective stresses and volume changes forced in the soils by atmospheric changes are discussed refering to those values obtained by other writers. ^{(6) (7)}
The effect of fluctuation phenomena on landslide movements, the setup of piezometric installations and other problems are discussed in this paper.