Drainage Works on the Basis of the Result of Underground Temperature Survey at One Meter Depth and its Effectiveness in the Miyagami Landslide Area

Abstract

In order to estimate the location of veins of ground-water, underground temperature survey at one meter depth was conducted at the Miyagami land slide area in Hyogo Prefecture. On the basis of he result of the survey, four water-collecting wells were constructed in and around the vein (shown Fig. 4). The Effectiveness of these works was examined by the results of the observation of ground-water level of nineteen bore holes in the land slide area from 1973 to 1977.
The following important results could be drawn from the investigations.
1. A large quantity of water which can be collected by drainage works exist in the vein of ground-water estimated by the survey.
2. A small water was observed in the well constructed outside the vein, but a large quantity of gushing water was observed when some draining bore holes were made toward the vein from the well. On the other hand, the works of the well through the vein was troubled with gushing water and extrusion of soil during construction.
3. The water-level of some bore holes digged in the vein falled remarkably in comparison with other bore holes.