WATER CUT-OFF METHOD FOR CONSTRUCTION JOINT OF UNDERGROUND CONCRETE STRUCTURE AND WATER CUT-OFF STRUCTURE

摘要

PROBLEM TO BE SOLVED: To cut off water, corresponding to a joint opening amount of a joint, by forming a groove on a tip face of a following concrete wall side on a preceding concrete wall, arranging a water expansion seal material in the groove and giving a placing joint to the following concrete wall. SOLUTION: The underground water entering a construction joint H from the natural ground due to opening of the construction joint H is led into a water cut-off space 22, and a water expansion seal material 15 is expanded due to the reaction with the underground water to block the water cut-off space 22. Further, since the construction joint H is blocked and expansion magnification of the water expansion seal material 15 is selected properly, water can be cut off even when a joint opening amount of the construction joint H is large. In this case, it is unnecessary to predict a joint opening amount of the construction joint H in advance and it is possible to correspond flexibly in accordance with the construction joint opening amount. Since the water expansion seal material 15 is expanded toward a water cut-off projecting part 23 side only in a groove 21, it is possible to concentrate expansion pressure of the seal material 15 on the water cut-off projecting part 23 side. Consequently, it is possible to position and fix the water expansion seal material 15 easily at low cost.