Reduction of water measures of a tunnel spring containing arsenic in the Hokusatu tunnel: Rock grouting of the mountains tunnel which applied a grouting technology of the dam

The Hokusatu tunnel which carried out this reduction of water measures is mountains tunnel of extension 4,850m to go through Mt.Shibi under construction in Road Crossing of Hokusatu which links Kagoshima Airport to The Hokusatu Region of Kagoshima Prefecture. From the Geological engineering low-speed zone of the neighborhood of tunnel center, groundwater including highly-concentrated arsenic gushed out approximately 300t per an hour, and influence on local water environment was concerned about. Therefore result 40t/h or less that enforced a reduction of water measures by the grouting technology of the dam were able to reduce water.