SYNTHETIC RESIN DRAINAGE SHEET

To provide a drainage sheet that can prevent the occurrence of various obstacles such as a decrease in drainage function and an increase in local water pressure even when a relatively large amount of spring water locally springs from a natural mountain into a tunnel.SOLUTION: A synthetic resin drainage sheet 2 includes a water channel portion 4 that extends in the vertical direction at the center in the width direction, and a pair of wall surface attachment portions 6 that extend in the vertical direction on both sides in the width direction of the water channel portion 4. Between the water channel portion 4 and one of the pair of wall surface attachment portions 6 and between the water channel portion 4 and the other of the pair of wall surface attachment portions 6, partition ribs 8 that protrude from one side surface and extend in the vertical direction are formed. A plurality of first projections 10 are formed on one side surface of the water channel portion 4, and a plurality of second projections 12 are formed on each side surface of the pair of wall surface attachment portions 6.SELECTED DRAWING: Figure 1 【課題】地山からトンネル内に局所的に比較的多量の湧き水が湧き出た場合にも、排水機能の低下や局所的な水圧の上昇等の種々の障害の発生を防止することができる排水シートを提供する。【解決手段】合成樹脂製排水シート２は、幅方向中央において縦方向に延びる水路部分４と、水路部分４の幅方向両側において縦方向に延びる一対の壁面取り付け部分６とを有する。水路部分４と一対の壁面取り付け部分６の一方との間、及び水路部分４と一対の壁面取り付け部分６の他方との間のそれぞれには、片側面に突出して縦方向に延びる区画リブ８が形成されている。水路部分４の片側面には複数の第１の突起１０が形成され、一対の壁面取り付け部分６のそれぞれの片側面には複数の第２の突起１２が形成されている。【選択図】図１