JPH01322013A - Temporary protection method for slope embankment rubble - Google Patents

Abstract

PURPOSE:To prevent scattering of ripraps and its collapse due to wave by covering at least the portion under a static water surface of the outer face of an inclined bank with metallic gauze and chains for weight, and its portion above the surface with permeable fiber cloth and chains for weight. CONSTITUTION:The main body 1 of an inclined bank formed of ripraps 2 piled up thereon has a permeable fiber sheet 3 covering the outer face of head portion thereof up to the respective neighbourhoods of a static water surface via its inclined face (a) on a wave incident side and its inclined face (b) on a filling side. And chains 4 for weight are mounted on the sheet 3. Then gauze 5 made of metallic line materials continuously covers the sheet 3 from a position above the lowest portion of the wave incident side inclined face (a) up to a position under the static water surface on the filling side inclined face (b). Then chains 6 for weight are mounted on the gauze 5 and fixed thereto. These chains 6 are installed at regular intervals and parallel to the normal line of the inclined bank, and doubled in the area under the static water surface where ripraps scoured in the vicinity of the water surface are apt to be accumulated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a slope embankment made of rubble built underwater, and a method for preventing scattering of rubble on a slope bank to prevent it from collapsing due to waves.

(Prior Art) Generally, as a breakwater or a revetment at the outer edge of a reclaimed land, a sloping embankment is constructed by piling up rubble stones and sloping both sides. In the end, this sloping embankment is constructed by pouring underwater concrete into the gaps between the rubble stones, or by stacking concrete blocks on the outside to cover the exterior, creating an underwater structure that will not collapse even in the face of waves.

(Problem to be Solved by the Invention) When constructing a slope embankment as described above, rubble is first piled up, and then concrete is poured to prevent collapse. After being piled up into a shape, there is a time interval before the final construction to prevent collapse is carried out, and during this time, the waves cause the rubble near the water surface to fall down along the slope, accumulate in the deep water, and cause the slope shaft to collapse. There is a problem in that it is deformed.

One possible solution to this problem is to temporarily install concrete blocks such as tetrapods on the surface of the inclined plate, but such a method requires a lot of time for construction and requires temporary covering. Therefore, there is a problem that it takes time to restore the original screen after that.

In view of the above-mentioned conventional problems, the present invention aims to provide a method for preventing scattering of sloped board rubble, which enables temporary covering of sloped boards and its removal in a short time, and which can sufficiently prevent the rubble from collapsing. This is what I did.

(Means for Solving the Problems) A feature of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose is to use an inclined plate constructed underwater and having at least the surface piled with rubble. The surface of the inclined plate is covered with a metal wire net having a mesh size so that the rubble cannot pass from below the static water surface of the incident side inclined surface to the opposite side inclined surface, and the outer surface of the metal wire net is Attaching a chain to prevent the metal wire net from peeling off, and covering at least the part above the still water surface of the surface of the inclined plate built underwater and at least on the surface with rubble with a water-permeable fiber cloth, On top of that, a metal wire net with a mesh size that cannot allow the rubble to pass is covered from below the static water surface of the incident side slope of the slope plate to the opposite side slope, and the outer surface of the metal wire net is The purpose is to attach a chain to prevent the metal wire mesh from peeling off.

(Function) This method for preventing the scattering of sloping rubble is that the outer surface is covered with a metal wire net and is held down by a chain, which prevents the rubble from floating up against the lifting force when the waves hit. , the debris on the outside or the receding waves will prevent you from falling. Furthermore, this also prevents the build-up of the lower part of the slope due to the accumulation of scoured rubble, and the deformation of the slope plate can be suppressed to the extent that it does not require repair.

Furthermore, the use of fiber cloth prevents rubble from collapsing at the corners of both edges of the top of the inclined plate above the water surface.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

Figures 1 and 2 show the case where the present invention is applied to a slope plate for a reclaimed seawall, and 1 in the figure is a slope plate main body formed by piling up rubble weighing 10 to 200 kg each. The outer surface of the top end of the inclined plate main body 1 is the wave incident side inclined surface a and the reclaimed surface IJ!
The slope of l#J is covered with a water-permeable fiber sheet 3 up to the vicinity of the still water surface. A chain 4 is attached to the edge of the fiber sheet 3 on the side of the incident side inclined surface a as a weight to prevent it from curling up. Next, this fiber sheet 3
A metal wire R5 is coated on top of the metal wire R5. This metal wire net 5 is made by weaving wire lobes into a mesh of such a size that the rubble 2 cannot pass through, and is placed from slightly above the lowest part of the incident side slope a to slightly below the still water surface of the reclaimed side slope. Cover continuously. After that, the metal wire lI45 was destroyed by the waves.
Chain 6 (N
o, I to ■) are placed on the metal wire net 5 and fixed.

The chains 6 are installed at regular intervals parallel to the normal line of the inclined plate. In addition, a double chain 6 is installed at a position slightly below the still water surface where rubble that has fallen due to scouring near the water surface is deposited, so as to strongly press down on the bulge of the slope.

(Experimental Example 1) 1. Experimental Conditions As shown in Fig. 3, the present invention was carried out by changing the covering positions of the m-fiber cloth and the metal wire mesh as shown in No. 1 to No. 3. For example A with no countermeasure shown in Figure 4 and example B using 6-ton tetrapot 7, waves with a period T = 5.8 seconds and a wave height H - 2.77 m were assumed, and each implementation The weight of rubble is 10 to 200 in both the example and each target example.
kg, and the metal wire mesh in each example has a diameter of 19”+
The test was conducted assuming that the wire rope was woven with a 36 mm mesh and the chain was 70 kg/m.

In addition, each test example No. 1 to No. 3 and target examples A and -B
Table 1 shows the height of the top of the sloping embankment and the water level at the time of the test.

In Table 1, LWL indicates the low water level, HWL indicates the high water level, and the crown height indicates the height based on the standard height in the area (for example, Tokyo Point). (The same applies to Table 2) In addition, in FIG. 3, for Test Examples No. 1 to No. 3, (a) represents a longitudinal sectional view, and (b) represents a plan view.

2. Changes in the shape of the inclined shaft body after 1 hour of wave action at the experimental site are as follows:
It was as shown in the figure. That is, a) Test Example No. 1 During the withdrawal, the chain fell along the rubble or slope near the still water surface, and was deposited at the chain No. III in Figure 3.

The deformation of the inclined base body is not significant.

(Example) Test Example No. 2 During the evacuation, it fell down along the slope or rubble near the still water surface, and was deposited at the position of chain M■ in Figure 3, No. 2. In addition, the crest and the shoulder at the rear of the crest were scoured by overtopping waves.

Deformation of the seawall is not significant.

c) Test Example No. 3 When the water was being drained, it fell down along the slope or rubble near the still water surface, and was deposited at the positions of the chains M■ to No. I in Figure 3, No. 3.

Deformation of the seawall is not significant.

2) Target example A During the evacuation, rubble on the surface layer fell down to the lower side of the slope and was deposited in deep water.

The deformation of the seawall is significant.

e) Target example B Do not allow the tetrapod to slide down the slope when it is being drained.

When the water receded, rubble near the still water surface was sucked out and fell into the deep water.

Deformation of the seawall is not significant.

(Experimental Example 2) ■, Experimental Conditions Table 2 shows the cases in which a metal wire net was attached to the arrangement shown in the above-mentioned example, with and without a fiber net attached, and the slope of the slope was different for each case. Test example No.
Tests No. 4 to No. 7 were tested under the same conditions as Experimental Example 1.

Table 2 2. Changes in the shape of the inclined basic body after 5 hours of wave action at the test site are shown in the fifth table.
It was as shown in the figure. That is, a) Test example No. 4 The rubble was scoured approximately 0.6 m from the shoulder of the top of the seawall on the incident wave side at around 0.5 m below the water surface, and the chain No. ■ in Figure 2 at a water depth of 2 to 3 m A thickness of approximately 0.6 m was deposited at the location. The top end on the incident wave side retreated by approximately 0.9 m due to scouring.

Additionally, the rubble at the top shoulder of the revetment on the reclaimed side was slightly scoured by the overtopping waves and fell near the water surface.

(Example) Test Example No. 5 No deformation was observed at the top shoulders of the seawall on the incident wave side and the reclaimed side due to the effect of the cloth. The number of rubble near the water surface on the incident wave side is approximately 0.
Chain No. 7 m has been scoured, and the water depth is 2 to 3 m in Figure 2.
, H with a thickness of about 0.7 m.

In addition, the rubble near the water surface on the reclaimed side was slightly scoured by the overtopping waves and fell below the water surface.

C) Test example No. 6 The rubble near the water surface from the shoulder of the top of the seawall on the incident wave side is approximately 0.5
It was scoured and deposited in a thickness of about 0.5 m at the chain point (2) at a water depth of 2 to 3 m in Figure 2, and approximately coincided with the line of the cross section at the time of construction. The top end on the incident wave side is approximately 0.3m due to scouring.
I retreated.

In addition, the rubble near the water surface on the reclaimed side was slightly scoured by the overtopping waves and fell below the water surface.

2) Test Example No. 7 No deformation was observed at the top shoulders of the revetment on the incident wave side and the buried shade side due to the effect of the cloth. The number of rubble near the water surface on the incident wave side is approximately 0.
Chain No. 5 was scoured, and the water depth is 2 to 3 meters in Figure 2.
It was deposited to a thickness of about 0.5 m at the position (2) and approximately coincided with the line of the cross section at the time of construction.

In addition, the rubble near the water surface on the reclaimed side was slightly scoured by the overtopping waves and fell below the water surface.

(Effects of the Invention) The method for preventing scattering of rubble in a slope mine according to the present invention is configured as described above, and is effective in preventing scattering of rubble due to waves by attaching fiber cloth, metal wire mesh, and weight chains so as to cover the outer surface of the slope embankment. The installation and removal work is much easier than installing concrete blocks such as tetrapods, and the work can be completed in a short time.

Furthermore, these materials can be removed after installation and reused for the next inclined shaft construction, which is economical.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. FIG. 4 is an explanatory diagram showing the experimental results of Experimental Example 1, and FIG. 5 is an explanatory diagram showing the experimental results of Experimental Example 2. a... Slanted surface on the incident side, b... Slanted surface on the reclaimed side, 1... Slanted basic body, 2... Rubble, 3...・Fiber cloth, 4...Chain, 5
...Metal wire mesh, 6...Chain.

Claims (2)

[Claims] (1) On the surface of a sloped embankment constructed in the sea, at least on the surface of which rubble is piled up, there is a mesh of a size that prevents the rubble from passing from below the still water surface of the slope on the entrance side of the slope to the slope on the opposite side. 1. A method for preventing scattering of slope embankment rubble, comprising covering the slope with a metal wire net and attaching a chain to the outer surface of the metal wire net to prevent the metal wire net from peeling off due to its weight. (2) Cover at least the part above the still water surface of the surface of the sloping embankment built underwater and at least on the surface with rubble piled up, with water-permeable fiber cloth, and on top of that, cover the entrance side slope of the slanted levee. A metal wire net with a mesh size that the rubble cannot pass from below the still water surface to the opposite slope is covered, and a chain is attached to the outer surface of the metal wire net to prevent the metal wire net from peeling off due to its weight. A method for preventing scattering of rubble on a slope embankment.