JPH11269849A - Breakwater and revetment structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive mound execution in soft ground by specifying the specific gravity and water content rate of lightweight material containing a hardened body block and forming the hardened body block of the specific gravity. SOLUTION: The hardened body block of specific gravity of 1.3-1.9 is piled up on sea bottom ground 22 to form a mound 15, a caisson 11 is set thereon, a foot protection block 13 is disposed around the caisson 11, the slope of the mound 15 is covered with a coating material 14, and in addition, a washing excavation protection mat 16 is disposed on the slope skirt of the mound 15 of an open sea side 12 to constitute a composite breakwater type breakwater or the like. Next, the hardened body block is formed of hydraulic material containing cement of prescribed parts weight and a dry powdered body such as coal ash, a lightweight material comprising foaming styrene particles of specific gravity of 1.6 or larger, and water or sea water of optimum water content ratio + (0-5)}%. Thereby since the lightweight hardened body block is used to construct the mound, even if the sea bottom ground is soft, the breakwater or the like can be constructed without needing ground improvement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a breakwater and a seawall structure.

[0002]

2. Description of the Related Art As a breakwater and a revetment structure, a structure body such as a hybrid embankment or a sloped embankment is used, and this hybrid embankment is, for example, as shown in FIG. And a caisson 1 on this mound 20
An upright portion such as 1 is provided, a consolidation block 13 is installed around the upright portion, and the slope of the mound 20 is covered with a covering material 14 as necessary. Conventionally, the mound 2
0 is formed by stacking concrete blocks and split stones, and the specific gravity of this concrete block is 2.1 to 2.4.
Degree, the specific gravity of natural stone is about 2.5 to 3.0, and when the seabed ground is soft because the specific gravity is large, it is necessary to construct the improved ground 21 using sand or the like in advance. The ground improvement work has a drawback that a large construction cost is required. Also, due to environmental protection and resource depletion, the price of stone and aggregate used for mound construction tends to increase, and stable supply is becoming increasingly difficult.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem.
It is an object of the present invention to provide a breakwater and a revetment structure that does not require ground improvement even in soft ground.

Another object of the present invention is to provide a breakwater and seawall structure that does not require stone or aggregate for mound construction.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a breakwater and a seawall having a mound formed by a hardened block having a specific gravity of 1.3 to 1.9. As described above, by using a hardened material block having a smaller specific gravity than a conventional mound material, a breakwater and a seawall can be constructed without performing ground improvement even if the seabed ground is soft.

In the present invention, the hardened material block having a specific gravity of 1.3 to 1.9 is composed of a hydraulic material containing cement and dry fine powder, a lightweight material having a specific gravity of 1.6 or less, and {optimum water content + A block formed of water or seawater within the range of (0 to 5)% can be used. This hardened body block is kneaded sufficiently after kneading the above-mentioned material, and is poured into a block formwork, and the formwork is vibrated until the electric resistance value of the hydraulic material thus placed is reduced. Can be formed.

The lightweight material having a specific gravity of 1.6 or less is, for example, a granular material having a particle diameter of about 1 to 10 mm formed from a resin material such as styrene foam, polyethylene, polystyrene, rubber or polyvinyl chloride, or 5 ~ 100
Cut pieces or fibers of about mm can be used, and the resin material may be discarded. Examples of the dry fine powder include coal ash, furnace slag, dry sludge, volcanic ash, and the like.Particularly, coal ash is preferable, and so-called coal ash generated by pulverized coal combustion is collected by an electrostatic precipitator. EP ash or preformed ash obtained by coarsening the EP ash can be used. In the present invention, the hydraulic material is 100 parts by weight of the dry fine powder,
3 to 150 parts by weight of the above cement, preferably 10 to 5 parts by weight
The one added with 0 parts by weight is used. If the amount of cement added is
If the amount is less than 3 parts by weight, no strength is exhibited, and if added in an amount exceeding 150 parts by weight, not only the strength does not increase so much but also problems such as cracks occur. In the present invention, besides cement and dry fine powder, additives such as gypsum, a water reducing agent and an admixture may be added, and furthermore, inorganic salts may be added.

As described above, even if seawater and / or water is added to the hydraulic material within the range of {optimum water content + (0-5)}%, the amount of seawater and / or water added is Since the amount of water added is extremely smaller than the amount of water added to conventional concrete or cement mortar, the hydraulic material does not have fluidity unlike concrete and the like, and becomes a wet powder state. Therefore, even with a lightweight material having a specific gravity of 1.6 or less, it is possible to disperse and add water and the like almost uniformly to the hydraulic material after addition, and furthermore, the lightweight material is unevenly distributed also in the hardened material block. Without dispersing, it can be formed to be substantially uniformly dispersed.

The above-mentioned optimum water content ratio means a water content ratio at which the maximum dry density is obtained by squeezing a specimen having each water content ratio a predetermined number of times while changing the water content ratio, and measuring the dry density. In the tamping test of JIS A 1210, a sample is divided into three layers in a 10 cm mold, and tamped 25 times for each layer with a 2.5 kg rammer to obtain an optimum water content. If a water content exceeding (optimum water content + 5)% is used,
Breathing may increase and cracks may occur during drying, or moisture may remain in the cured product and hair cracks may occur. On the other hand, if the water content is less than (optimum water content + 0%), compaction is extremely difficult, and workability is deteriorated, so that casting is difficult, and sufficient strength may not be exhibited. For kneading, it is preferable to use a device such as a forced kneading mixer, a biaxial forced kneading mixer, or a low water content forced continuous kneading mixer for kneading general ready-mixed concrete, since sufficient kneading is performed.

After the hydraulic material is sufficiently kneaded, the positive and negative electrodes are placed in a mold with a predetermined distance therebetween, and a kneaded material of the hydraulic material is poured. Then, after the casting, while measuring the electric resistance between the electrodes obtained by energizing each electrode, the absolute value of this electric resistance does not matter, and the tendency of the relative change of each kneaded material itself over time. In the above, the kneaded material is compacted by vibrating the mold until the electric resistance value decreases. Here, the vibration is, for example, using a hydraulic table vibrator “HST 10F 18C” (Exen Co., Ltd.) with a centrifugal force of about 5 to 10 tons and a vibration frequency of about 1000 to 5000 rpm, preferably 4000
What is necessary is just to set it to about 4500 rpm.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a breakwater or seawall structure of a hybrid embankment type, which has a specific gravity of 1.3.
The 1.9-hardened body blocks are stacked on the seabed ground 22 to form a mound 15, and an upright portion such as a caisson 11 is placed on the mound 15, and a stiffening block 13 is placed around the upright portion. The mound 15 is installed, the slope of the mound 15 is covered with the covering material 14, and the scouring prevention mat 16 is arranged at the bottom of the mound 15 on the open sea side 12.
If the mound 15 is constructed using the hardened body blocks having a specific gravity of 1.3 to 1.9 in this way, it is possible to construct a breakwater or a seawall without improving the ground even if the seabed ground is soft. Will be possible.

Here, for example, 85 parts by weight of coal ash as dry fine powder, 15 parts by weight of ordinary Portland cement, 3 parts by weight of NaCl as an admixture, {optimum water content + (0-5) ｝% Water and particle size 1-1 as light weight material
If the cured body block is formed by 30% of styrene foam of about 0 mm, the specific gravity of the cured body block is 1.2 to 1.0.
It will be about 3.

Next, a method for manufacturing the cured body block will be described. First, coal ash as dry fine powder was
5 parts by weight, 15 parts by weight of ordinary Portland cement,
3 parts by weight of NaCl as an admixture were mixed using a forced kneading mixer, and the resulting mixture was mixed with {optimum water content +
(0-5)% water is added and kneaded sufficiently to prepare a water-containing kneaded product. Next, a mold (not shown) for a hardened block having a substantially cubic inner shape and an inner dimension of 1600 × 1600 × 1600 mm is placed on a hydraulic table vibrator (not shown). An electrode is arranged in the inside, connected to an electric resistance measuring device (not shown), and the above-mentioned hydrated kneaded material is poured into a cured body block mold. Then, the cured body block form is centrifuged by a hydraulic table vibrator with a centrifugal force of 10 to 40 tons and a vibration frequency of 3000 to 4000 rpm.
While applying a certain degree of vibration, compact it until the electrical resistance drops sharply. If the mold for the cured body block is released after 24 to 48 hours after compaction, the cured body block is completed.

Next, in order to compare and examine the effects of the present invention, the required improvement ratio, required improvement width and required improvement of the ground in the case of constructing the inclined levee with rubble and the case of constructing the inclined levee with the hardened block are described. The improved volume was calculated.

Here, the sloping embankment is formed on a foundation ground having three levels of adhesive strength as shown in FIG. 5 using rubble, a hardened material block, and sand for improvement using the material shown in FIG. , The cross-sectional dimensions of FIG. In addition, the safety factor for stability shall be 1.3 or more, and the required improvement rate, required improvement width and required improved volume of the ground to satisfy this safety factor shall be described in "Technical Standards for Port Facilities and Revised Explanations" (Heisei Heisei). It was calculated based on the Japan Port Association in June of the first year, and is shown in FIG.

In FIG. 6, a comparison between the results of Case No. 1 and Case No. 4 shows that when a sloped embankment is constructed by using a hardened block while the foundation ground has the same adhesive strength, Required improvement rate of the ground,
It can be seen that the required improvement width and the required improvement volume can be reduced.
Also, from the results of Case No. 5 and Case No. 6, it can be seen that the use of a hardened block satisfies the safety factor of 1.3 even on soft ground and that an inclined levee can be constructed without ground improvement. I understand.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a breakwater of the present invention.

FIG. 2 is a sectional view showing a conventional breakwater.

FIG. 3 is a sectional view of an inclined levee.

FIG. 4 is a table showing materials of rubble, hardened material blocks, and sand for improvement used in the sloped dike of FIG. 3;

FIG. 5 is a table showing conditions of a foundation ground for constructing the sloped levee of FIG. 3;

FIG. 6 is a table showing a ground improvement ratio, an improvement width, and an improvement volume required for constructing the inclined levee of FIG. 3 under the conditions of FIGS. 4 and 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Caisson 12 Open sea side 13 Rooting block 14 Coating material 15 Mound 16 Scour prevention mat 22 Submarine ground

Continued on the front page (72) Inventor Kazuto Fukudome 2-5-8 Kitaaoyama, Minato-ku, Tokyo

Claims (2)

[Claims] 1. A breakwater and a seawall comprising a mound formed of a cured block having a specific gravity of 1.3 to 1.9. 2. A hardened material block comprising: a hydraulic material containing cement and dry fine powder; a lightweight material having a specific gravity of 1.6 or less; and an optimum water content ratio of + (0 to 5)%. 2. The breakwater and seawall structure according to claim 1, wherein the breakwater and seawall are made of water or seawater.