PURPOSE: To prevent spring water from intruding into an excavated ditch by boring small holes to places where spring water gushes out of the excavated face, and by inserting flexible tubes into the holes with their ends raised upward for opening to the air.

CONSTITUTION: Holes in small diameter are bored to places 2a and 2b wherefrom spring water gushes out on an excavated face 1, and flexible tubes 4a and 4b are inserted therein and gaps around the tubes are sealed up with sealing material 5. The tubes 4a and 4b are raised upward with their upper ends opened to the air. Then gushing-out of water is checked with the Bernoulli's theorem applied. Thereby pumping out in the excavated ditch becomes unnecessary and subsidence of ground can be prevented.