| 摘要 |
PURPOSE:To enable reduction of the back pressure of a banking layer, by a method wherein a water permeable sheet is laid in a range of from the front part of the bottom part of a caisson to the upper part of the back, and the water permeable sheet, having the one end secured to the caisson, is developed in a back-filling layer to form a baning layer. CONSTITUTION:Cobble-stone 4 is banked on a replacement laeyr 3, in which a sea bottom ground 3 is replaced with cobble-stone and the like, to form a sink bed 5, and a water permeable materail 11 is laid and extended in a range of from a front 22 of a caisson 2, intended to be sunk, to a portion under a banking layer. The caisson 2 is sunk on a sink bed 5, the interior of the caisson is filled with a fill 6, and an upper surface part 23 is blocekd up. The water permeable sheet 1, the one end iof which is secured to a back 21 of the caisson 2, is about horizontaly extended, and banking layers G1-Gn are formed between the sheets 1. Further, the water permeable sheet 11 is vertically laid to the back 21 of the caisson 2. This enables decerase of an eaerth pressure exerted on the back of the caisson. |
