Effects of drainage works in Sarukuyouzi landslide.

The landslides locating at Tertiary mudstone area greatly occur in snowmelting seasons. The drainage works have been often used to prevent these landsliding. In order to establish the planning method for those drainage works, we measure the fluctuation phenomena of porewater pressure in Sarukuyouzi landslide. This paper discusses the drainage effective area through the conclusions drawn from a comparison of the results obtained by analtical methods and field data.