JPS603567B2 - Construction method of embankment body with horizontal top surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of constructing an embankment body with horizontal end faces.

In the conventional construction technique for the above-mentioned levee body, the dam body excluding the concrete cover with a horizontal top surface is manufactured using a boxyard, and after being covered with a temporary steel plate, etc., the caisson levee body is towed and hemmed. After that, a method is being explored in which an earth and sand carrier is brought alongside the embankment body and the packed earth is introduced into the bulkhead from above the caisson embankment using transport equipment such as grab buckets.

However, with the above-mentioned bundling technology, a temporary cover is attached to the top of the caisson made from a box yard when it is towed to the site, but there are concerns about its pressure resistance and water leakage resistance.

On the other hand, to address this concern, it is desirable to build a permanent ceiling made of reinforced concrete as an integral part of the caisson.
Previously, caissons with lids were not used because the ceiling would become obstructed when filling. Therefore, the horizontal concrete cover slab had to be constructed as cast-in-place reinforced concrete after the filling work was completed.

However, since the construction of the concrete cover slab with a horizontal upper end surface requires offshore work, if the work gets wet during the work, the work has to be stopped, and the construction period is subject to restrictions depending on sea conditions and can vary significantly. In addition, there are problems with the formwork assembly work and on-site concrete work itself, which are carried out under adverse conditions different from those on land, and with sufficient construction management to obtain high-quality concrete, such as curing of cast-on-site concrete. However, this had the disadvantage that construction schedule planning was severely restricted in rough seas.

The method of constructing an embankment body with a horizontal end face according to the present invention satisfies the above-mentioned requirements and greatly saves labor for on-site offshore construction, and the method is such that a concrete lid plate with a horizontal end face is integrated with the embankment caisson. , a process of constructing an embankment body using a box yard in the shape of a nearly closed box, and a process of injecting a suspension of water and sand through an injection port previously provided in the embankment body after launching, towing, and skirting. It is characterized by consisting of: Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIG. 1, the embankment body 1 is built as an integral structure with the embankment caisson up to the horizontal cover concrete slab 2 in a box yard, and after being launched, it is towed to the site. When a box is built inside a dry dock, the superstructure is also built at the same time as a box built inside the dry dock, so the drainage may become too deep when leaving the dock. - (buoyancy tank) 3 is used. Alternatively, the auxiliary lifting method of a hoist ship may be used instead. As shown in FIG. 2, after the caisson is hemmed on the basic stone leveling surface 4 prepared in advance at the planned location for hemming the embankment body, the filling work is immediately started.

As shown in FIGS. 1 and 2, filling soil 5 is temporarily placed on the seabed in advance. It is preferable to embed a rectangular steel pipe (gas pipe) 7 in the hole 6 of the horizontal lid concrete slab 2 as an inlet for Chinese sand or a drain for draining water.

For transporting the Chugonyoshi sand through pipes, we are exploring a method of pumping it as a suspension of water and sand with a volumetric sand ratio of about 10%, similar to a normal pump-type 7-barrel ship.

In the present invention, as shown in FIG. 2, a submersible sand pump 9 suspended from a barge 8 as a pipeline system
Filled earth and sand 5 temporarily placed on the seabed is sucked up, pressurized by a small booster pump 10 on a barge 8, and then passed through a flexible pressure hose 11 to a hole 6 on the lower side of the horizontal lid concrete slab 2.
The remaining water is injected into the caisson from the hole 6 in the horizontal cover concrete plate 2 and drained through the hose 12. In another embodiment of the present invention, as shown in FIG. 3, an earth carrier 8' is used as the barge 8. It is more convenient to suspend the sand pump 9 with a cutter directly into the chest and extract the slurry while adding water by jetting water.

In this filling method, variations in sand content in the slurry can be tolerated over a wide range. Furthermore, if the surplus water is allowed to flow back, there is no risk of the surplus water contaminating the seawater. In addition, if inspection holes (not shown) are provided in the horizontal lid concrete slab at appropriate locations, the sand filling status can be checked using a rod-shaped inspection tool, and the sand can be checked through these holes after sand filling work. Cement mortar can also be injected into the missing areas.

In the above embodiments, only sand was used as the filling material, but other materials having a particle size larger than sand may also be used. or,
In the embodiment described above, the inlet was provided in the side wall and the outlet was provided in the horizontal cover concrete slab, but these may be provided in either the side wall or the horizontal cover concrete slab. According to the present invention, it is possible to omit the conventional on-site pouring work for horizontal ceiling concrete plates, and the horizontal cover concrete plate can be manufactured as one piece under thorough construction management within the box yard. Therefore, a horizontal lid concrete plate with satisfactory strength can be obtained.

In addition, even when towing from a box yard, since the horizontal cover concrete slab is pre-fabricated, there is no need to worry about seawater flowing in, which is convenient when there is no box yard near the site and the boat must be towed from a distant yard. It is.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram at the construction stage of the embankment body of the present invention, Figure 2
The figure is an explanatory diagram of the method of the present invention, and FIG. 3 is an explanatory diagram of another embodiment of the present invention. 1... Embankment body, 2... Horizontal lid concrete plate, 3. ．．・．． ．．・Floater, 4... Basic chestnut stone leveling surface, 5....・．． Filler sand, 6...Horizontal lid concrete plate hole, 7...Rectangular steel pipe, 8...
... Barge, 9... Submersible sand pump, 10...
...Small booster pump, 11...Flexible pressure-resistant hose, 12...Hose, 8'...Manga ship. Key figure O2 figure S3 figure

Claims (1)

[Claims] 1 The process of constructing a dam in a box yard by assembling the horizontal concrete slab with the dam body caisson in an almost closed box shape, and after launching, towing, and installing, water is poured into the dam from a pre-installed injection port. A method for constructing an embankment body with a horizontal top surface, the method comprising the step of injecting a suspension of sand and sand.