| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure and method which prevent destruction of a levee by guiding water into a water conveying and draining tunnel for reduction of infiltration velocity, not by blocking infiltration water to the levee.SOLUTION: Inside an existing levee 1, a water draining tunnel 2 is constructed along the longitudinal direction of the levee 1 by a shield tunneling method. As the segment for constituting a tunnel wall surface, a water-permeable segment 3 is employed, having a structure including, for example, the outer peripheral surface of a segment made of water permeable porous concrete to which a thick chemical fiber layer is attached. Preferably the segment has a permeability coefficient in the range from about 10to about 10. Furthermore, a water blocking wall 4 is vertically constructed at the ceiling part of the water draining tunnel 2. |
