福島県原町市の地盤沈下とその対策

概要

論文の詳細を見る
Land subsidence in Haramachi City occurs selectively over the unconsolidated alluvium, which has been deposited since 12,000 years B.P. Precise levelling revealed the maximum land subsidence of more than 1.5 m for 22 years in the extent of 30 km^2. Ground water in the formations was squeezed and flowed into the confined aquifers by the artificial lowering of their piezometric surfaces. Consequently, as a result of consolidation of the formations land subsidence occurred. Various kinds of damages such as uneven sinking of paddy field, undulating of roads and waterways, declining of houses, drying up of wells, and others were caused by the landsubsidence. The damage was estimated more than 16 billion yen. Therefore, the following countermeasures are under performance for prevention of land subsidence: ground water withdrawal is controlled for whole uses in two restricted areas, 17.7 million m^3 of ground water for industrial and agricultural uses are replaced by the water of dam, and damaged arable land and facilities for agriculture are restored. The groundwater to be converted amounts to 80% of the total volume of ground water extracted in Haramachi City in 1977. It is expected that land subsidence will be stopped by the convertion.
日本地質学会の論文
1983-12-25