JPH0555654B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a construction method for constructing underground walls at sea for constructing marine structures and the like.

[Prior Art and Problems to be Solved by the Present Invention] Conventionally, as this type of construction, construction by temporarily constructing a rocky island is generally known.

However, this requires the construction of a large-scale temporary construction island, which lengthens the overall construction period and increases costs.Therefore, there was a desire to develop a construction method that could be constructed directly from the sea without requiring a construction island.

However, it is difficult to ensure the difference in water head for stabilizing trench walls, and there are concerns that the stabilizing liquid used when excavating trenches for forming continuous underground walls may leak out, and that structures such as reinforcement for forming continuous walls may be exposed to seawater. Therefore, due to problems such as measures to prevent corrosion of metal by seawater, no construction method has been developed that can reliably form a continuous wall from the sea.

This invention was devised in view of the above-mentioned circumstances, and its purpose is to provide a construction method that can securely secure the water head, prevent the stabilizing liquid from flowing out during trench excavation, and provide complete corrosion prevention measures. be.

[Means to solve the problem]

According to this invention, two steel sheet piles are placed in parallel in parallel to each other with their upper ends protruding above the sea surface into the seabed ground where a trench for forming a continuous wall is to be excavated, and the seawater between the two groups of steel sheet piles is drained. In addition to replacing it with a stabilizing liquid, an excavator will be inserted from the sea between the two steel sheet pile groups to excavate a groove for forming a continuous wall.

Then, a continuous wall reinforcing cage with non-corrosive formwork attached to the underwater part of the continuous wall is inserted into the excavated formation trench, and concrete is poured to form the continuous wall. be.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

As shown in FIG. 1, the underground continuous wall 1 is constructed by excavating a formation groove 3 in the seabed ground 2, and is provided so that the upper part thereof is under the sea.

When constructing the underground continuous wall 1 having such a configuration, first, the steel sheet piles 5 are successively driven into the seabed ground 2 so that the upper end thereof protrudes above the sea surface 4, and then two rows are formed. Both steel sheet pile groups 7, 7 are formed in parallel.

After that, a flat plate 8 is arranged between the guide fittings 6, 6 provided on the opposing web portions 5a of both steel sheet pile groups 7, 7, and each flat plate 8 and both steel sheet pile groups 7, 7
A mortar 9 is filled between the two. Further, the upper ends of each steel sheet pile 7, 7 are connected with a steel material 25 and fixed to a pier 26, etc., and a plate 10a and concrete 10b constituting the partition wall 10 are provided at predetermined positions. (See Figures 2 to 4 above.) Next, both steel sheet pile groups 7, 7, both partition walls 10, 10 provided between both steel sheet pile groups 7, 7 at a predetermined interval, and the seabed surface 11 surround it. The seawater 13 in the space 12 is replaced with a stabilizing liquid 14 by a replacement means. (Figure 2,
(See FIG. 5) Thereafter, the excavator 15 is inserted between the two steel sheet pile groups 7, 7, and the continuous wall forming groove 3 is excavated in the seabed ground 2. Here, reference numeral 16 is an excavation ruler for setting the excavator 15 at a predetermined position. (See Figure 6) Next, a non-corrosive formwork 1 made of cloth or plastic is placed in the underwater part of the continuous wall 1 into the forming groove 3.
Insert the continuous wall reinforcing bar cage 18 to which 7 is attached.

Concrete 19 is then placed to form continuous wall 1. (See Fig. 7 above.) To insert the reinforcing bar cage 18 into this formation groove 3 and place concrete 19, first excavate the trench 3 for forming the preceding element, and then construct the reinforcing bar cage 18. Include. At this time, as the formwork 17 for the underwater part, a plastic formwork, a cloth formwork, or a double cloth formwork is used. At the same time, the cover plate 20 is also installed. (See FIGS. 7 and 8) Next, a groove 3' for forming a trailing element is excavated. Thereafter, a reinforcing bar cage 21 having the same configuration as the reinforcing bar cage 18 of the preceding element is erected, and concrete 19 is poured. (See FIGS. 8 and 9) Next, when the construction of the trailing element is completed, the partition wall 10 is replaced. At the time of this replacement, a water stop wall 22 made of a double cloth form and cast with mortar is constructed in the squares of the existing continuous wall 1. And each water stop wall 22
A portion 12 surrounded by the wall frame 17 and the flat plate 8
The stabilizing liquid 14 of ' is replaced with seawater and the partition wall 10 is replaced, but at the same time, the steel sheet pile groups 7, 7 that have been water-stopped with mortar are removed and used for construction of a new continuous wall 1.

Then, the forming groove 3 is excavated again, and a new continuous wall 1 is formed as described above. (See Figures 10 and 11 above.) By repeating such operations, the underground continuous wall 1 is constructed on the sea.

In addition, both steel sheet pile groups 7, 7 and both inner partition walls 10, 1
0, the seawater in the space 12 surrounded by the seabed surface 11, and the stabilizing liquid in the part 12' surrounded by each of the water-stop walls 22, the formwork 17, and the flat plate 8, respectively. As a means for replacing the water with seawater, first, the interior of the replacement bag 24, which is provided with a drain plug 23 at the lower end, is filled with a stabilizing liquid or seawater.
2 or the enclosed portion 12' is filled with a replacement bag 24 to drain the seawater or stabilizing liquid.

The drain tap 23 is then opened to fill the space 12 or the enclosed area 12' with stabilizing liquid or seawater.

In this way, the replacement is completed. (See FIG. 5 above.) [Effects of the Invention] The present invention has the configuration described above and has the following effects.

After replacing the seawater with a stabilizing liquid, an excavator was inserted to create a continuous wall formation groove between the two steel sheet pile groups, which were cast in two parallel rows into the seabed ground with their upper ends protruding above the sea surface. By excavating, it is possible to reliably maintain the water head difference even if the outer periphery is seawater without temporarily constructing a built-up island, and it is possible to reliably excavate a forming trench that maintains the stability of the trench wall.

A flat plate is placed between each guide fitting provided on the opposing web parts of both steel sheet pile groups, and a waterproof mortar is filled between this flat plate and the steel sheet pile, and the part of the continuous wall reinforcing bar cage that becomes underwater. By attaching non-corrosive formwork to the wall, the concrete cover can be completely removed, and the metal parts of the continuous wall will not come into contact with seawater, making it possible to create a structure with good durability against corrosion.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a continuous wall constructed by the method of this invention, FIG. 2 and FIGS. 5 to 11 are schematic process diagrams showing the method of this invention, and FIG.
A view taken along line A, and FIG. 4 is an enlarged view of section B in FIG. 2. DESCRIPTION OF SYMBOLS 1... Underground continuous wall, 2... Seabed ground, 3... Formation groove, 4... Sea surface, 5... Steel sheet pile, 5a... Web part, 6... Guide metal fittings, 7... Steel sheet pile group, 8...
... Flat plate, 9 ... Water stop mortar, 10 ... Partition wall, 10a ... Plate, 10b ... Concrete, 11 ... Seabed surface, 12 ... Space, 12' ...
...Enclosed part, 13...Seawater, 14...Stabilizing liquid, 15...Excavator, 16...Drilling ruler, 17
... Formwork, 18 ... Rebar cage, 19 ... Concrete, 20 ... Cover plate, 21 ... Rebar cage,
22...Water stop wall, 23...Drain plug, 24...Replacement bag, 25...Steel material, 26...Pier.

Claims (1)

[Scope of Claims] 1. Both steel sheet pile groups connected to the seabed ground in two rows in parallel so that their upper ends protrude above the sea surface, and guide fittings provided on opposing web portions of these steel sheet pile groups. A waterproof mortar is filled between each of the flat plates arranged in between, and then the steel sheet piles are surrounded by both the steel sheet pile groups, both middle partition walls provided between the steel sheet pile groups at predetermined intervals, and the seabed surface. replacing the seawater in the space with a stabilizing liquid using a replacement means, then inserting an excavator between the two groups of steel sheet piles to excavate a continuous wall groove in the seabed ground, and inside the continuous wall groove. A method for constructing an underground continuous wall at sea, characterized in that the continuous wall is formed by inserting a reinforcing bar cage for the continuous wall with a non-corrosive formwork attached to the underwater part of the continuous wall. 2. The replacement means is to fill a replacement bag with a drainage plug at the bottom end with a stabilizing liquid, fill the area to be replaced with the replacement bag and drain the seawater, and then drain the water. 2. The construction method according to claim 1, wherein the stabilizing liquid is filled into the space by opening a stopper.