HORIZONTAL WELL CONSTRUCTION METHOD, SHORT WELL PIPE, AND METHOD AND DEVICE FOR DECONTAMINATING CONTAMINATED SOIL BASED ON GROUNDWATER CIRCULATION VIA HORIZONTAL WELL

PROBLEM TO BE SOLVED: To construct a horizontal well toward a target location under the ground without damaging the natural environment etc., or without being hindered by an existing building, and to decontaminate contaminated soil under the ground by suppressing fluctuation of a groundwater level or ground subsidence, and accordingly by reducing a load on the natural environment etc. SOLUTION: In the construction of the horizontal well, while the ground is horizontally excavated from a shaft 1 toward the target location under the ground, short well pipes 20 are successively connected together to be extended in an excavated hole, and arranged at locations facing to an underground area as a water flowing target. Each short well pipe 20 has water flowing holes 21 blocked with plug members P. After arrival at the target location, by virtue of decomposition of the plug members P at least by groundwater, the water flowing holes 21 obtain water flowing ability, and therefore the horizontal well 2 or 3 formed of a group of the short well pipes 20 is constructed. According to a method of decontaminating the contaminated soil, the water collecting horizontal well 2 and the water returning horizontal well 3 are constructed from the interior of the shaft 1 to a contaminated soil area CA, and groundwater containing contaminated substance, that flows from the well 2 into the shaft 1 is pumped up to be decontaminated by a decontaminating device 5, followed by returning decontaminated water via the well 3 to the contaminated soil area CA. In this manner the groundwater is circulated to decontaminate the contaminated soil. COPYRIGHT: (C)2006,JPO&NCIPI