JPH0577804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a seawall structure having excellent strength and stability against external forces such as wave force and seismic motion, and a method for constructing the same.

"Prior Art and Its Problems" As a revetment structure for ports, rivers, dams, etc., for example, an enclosure is constructed from the bottom of the water to the surface of the water using revetment walls such as caissons, steel pipe sheet piles, and steel plate cells. A revetment structure is known that is constructed by inserting filling materials such as chestnut stone, sand, and clay, and letting them settle and pile up.

However, in the case of the above-mentioned revetment structure,
The following problems arose.

[] Conventional filling materials such as chestnut stone, sand, and clay do not have adhesive strength, and the entire seawall consisting of the filling material and the seawall is not an integral structure, so it is difficult to resist waves, for example. Due to vibrations caused by earthquakes, etc.
Filling materials may shake inside the revetment structure and easily liquefy. As a result of this liquefaction, the volume of the filler material decreased and the top of the seawall began to sink, posing a risk that the entire seawall body would be destroyed over many years.

[] Since the above-mentioned filler materials also have a high specific gravity, the total weight of the filler materials inside the revetment structure also becomes large, and therefore, strong earth pressure builds up on the revetment wall, causing damage to the revetment wall. Cause. When such a situation is predicted, it is necessary to use thick-walled revetment walls in advance, which increases the amount of expensive revetment walls used, which is extremely uneconomical.

[] Furthermore, the above-mentioned filling materials are often used in combination with each other, but since the materials are introduced from above the water surface, it is not possible to stack the filling materials evenly inside the seawall structure. A gap is formed in a part of the filled filling material, and the revetment wall and the filling material do not have an integrated structure. In addition, there was an inconvenience that the strength of the entire seawall body varied.

"Means for Solving the Problems" Therefore, in order to solve the above-mentioned problems, in the revetment structure and construction method of the present invention, filling material made of coal ash slurry is used in the revetment wall body. By pouring into the enclosed interior and hardening this filling material, the filling material and the revetment wall are integrated, and the revetment wall has a structure in which the revetment wall and the filling material are integrated. It is characterized by the provision of an integration means for increasing the adhesive area and improving the integration force between the revetment wall and the filling body.

In addition, in the construction method, after the filling material made of coal ash slurry is deaerated, the filling material is
Passing through a transport pipe with a discharge port located near the water bottom surrounded by a revetment wall, pouring and depositing it on the water bottom,
The filling material is then cured to integrate the filling material and the revetment wall.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an example of a revetment structure having a revetment structure according to the present invention, and reference numeral 1 in the figure indicates the revetment structure. This revetment structure 1 is constructed on the water bottom B of the seawall construction area, and the restraining stones such as chestnut stones 2 are piled up in a trapezoid shape on the water bottom B.
A bottomed cylindrical caisson (revetment wall) 3 having a bottom plate serving as a means for integrating with the filling material described later is placed on top, and the inside of this caisson 3 is filled with the filling material 4. It is. The holding stone 2 is the caisson 3
This is a foundation piled up in order to fix the stone at a predetermined position on the water bottom B of the seawall construction area, and this restraining stone 2 is made of a material with a large specific gravity, and its type is not particularly limited. Also, caisson 3
The inside of the caisson 3 is filled with filler material 4 without any gaps, and is integrated with the filler material 4 to form a seawall. Concrete or the like is suitably used as the material for forming the caisson 3. The lower part of a caisson 3 is buried in the upper part of the holding stone 2, and the inside of this caisson 3 is filled with a filling material 4.

For the filling material 4, a slurry made of coal ash is used which has adhesive strength that does not cause liquefaction against wave force, seismic force, etc. The coal ash used here is generated from coal-fired power plants and other coal-burning plants, and has an adhesive strength of 0.5 to 2 Kgf/ ^cm2 and a density of 1.4 to 1.7 g/ ^cm3. is desirable.

Depending on the type of coal ash, the hydraulic properties may be extremely weak and sufficient compressive strength cannot be expected due to increased density. In such cases, coal ash containing hydraulic substances such as cement and gypsum etc. Strength can be increased by adding a curing aid.

Among hydraulic substances, the greater the amount of cement added, the greater the strength, but if it is added up to 5 parts by weight per 100 parts by weight of coal ash, sufficient strength can be obtained as a foundation. Calcium-based hardening materials such as granulated slag and quicklime can be expected to have the same effect as cement. In the case of gypsum, the optimum amount is usually 2 to 10 parts by weight, but up to 50 parts by weight can be used. Furthermore, adding gypsum when adding cement is very effective, and usually by adding cement and gypsum at a ratio of about 1:2, a large increase in strength can be achieved. Note that the gypsum in this case may be any of anhydrous, hemihydrous, and dihydric gypsum, and each has an optimum value for its addition amount. In addition, coal ash contains sand,
Aggregates such as gravel and bottom ash may be added to the extent that they do not impair the fluidity of the slurry. Addition of aggregate also increases the strength of the ground after pouring. Water is added to the coal ash to form slurry S. As water, in addition to regular tap water, well water, and other clean water, seawater, lake water, rainwater, and the like can also be used. In particular, seawater and lake water are suitable for use in landfills and the like because they are easily available and inexpensive.

Next, to explain the method of constructing the seawall structure of the present invention, first, chestnut stones and the like are removed on the water bottom B using a screed-type, curtain-type, etc. dumping device and a vibrating-type, screed-type, etc. rubble leveling machine. Build a trapezoidal base made of 2 holding stones. Then,
The caisson 3 is placed so that the lower part of the caisson 3 is buried on the holding stone 2, and is fixed at that position. Further, the inside of the caisson 3 is filled with the filling material 4 without any gaps. At this time, in order to fill the inside of the caisson 3 with the filler material 4 without leaving any gaps, a device as shown in FIG. 2, for example, is used. That is, in FIG. 2, numeral 5 is a mixer, and this mixer 5 is
Slurry S as the filling material 4 is obtained by mixing coal ash with a predetermined amount of water. A storage tank 6 for storing coal ash and a storage tank 7 for storing water are arranged above the mixer 5, and these storage tanks 6 and 7 and the mixer 1 are connected by raw material pipes 8 and 9, respectively. Water is supplied to the storage tank 7 from the water surface of the seawall construction site using a water suction pump 10 through a water supply pipe. In addition, mixer 5 has
An agitator 11 for further kneading the slurry S mixed by the mixer 5 is connected to the agitator 11, and a deaerator 12 for efficiently removing air bubbles in the slurry S is provided in the agitator 11. This deaerator 12 is provided with a vibrator (not shown) that vibrates the slurry S. The deaerator 12 uses its vibrator to remove air bubbles from the slurry S, so when the slurry S is placed in water, air bubbles are removed from the slurry S in the water.
Therefore, the air bubbles do not disperse the SS in the slurry S into the water and cause contamination of the seawall construction area.

A pump 13 is connected to the agitator 11, and a transport pipe 14 is disposed in the pump 13. As shown in FIGS. 1 and 2, the transport pipe 14 is connected to the seawall structure 1 from the water surface of the seawall construction site.
The discharge port 15 extends toward the bottom of the caisson 3, and a discharge port 15 is provided near the bottom. Discharge port 15
is embedded in the slurry S deposited on the bottom of the caisson 3 when the slurry S is discharged from the discharge port 15. The reason for this is that when slurry comes into contact with water and mixes with water, its properties change and the physical properties after solidification deteriorate. This is to cause new slurry S to be discharged.

In addition, in the degassing device 12 described above, as a method for removing air bubbles in the slurry, a vibrator was provided to vibrate the slurry S to remove air bubbles, but in addition to this, any of the following methods may be used. It's okay.

(1) Apply pressure to the slurry to dissolve air bubbles into the slurry.

(2) Heat the slurry to remove air bubbles.

(3) Place the slurry under vacuum to remove air bubbles.

Then, coal ash and water are put into mixer 5 at an appropriate mixing ratio, and after mixing, they are thoroughly kneaded and degassed by agitator 11 and deaerator 12 to obtain slurry S. Next, this slurry S is pumped into the pump 13.
The liquid is sent to the transport pipe 14 through the transport pipe 14, and discharged from the discharge port 15 of the transport pipe 14 onto the inner bottom of the seawall structure 1, where it is deposited. The slurry S cast in this way has a density, viscosity, and water content ratio (water amount/
This makes it possible to maintain the amount of coal ash (coal ash amount). The ground for the revetment made of Slurry S takes full advantage of the self-hardening properties of coal ash, so it has a compressive strength of 1 kg/kg.
It has sufficient strength of cm ² or more.

FIG. 3 shows an example of a revetment structure having the revetment structure of the present invention, and reference numeral 16 in the figure indicates the revetment structure. This seawall structure 16 is
It consists of steel plate cells (revetment walls) 17 whose lower portions are embedded almost perpendicularly to form an enclosure, and filling materials 4. The steel plate cells 17 are filled with filling material 4 without any gaps, and are integrated with the filling material 4 to form a seawall.
On the inner wall surface of No. 7, there is a protrusion that constitutes an integration means that increases the unifying force of the inner filler and the revetment wall by entering into the inside of the inner filler and joining together, that is, a projection that is approximately opposite to the inner wall surface. A plurality of ribs 18 are provided vertically.
These ribs 18... allow the filling material 4 and the steel plate cells 17 to
... means that when the filling material 4 is injected into the enclosure formed from the steel plate cells 17, it becomes a stronger integral structure.

Further, sheet piles or the like can also be used as the seawall. Sheet piles have a slightly low watertightness, so there is a concern about scour, but because sticky coal ash slurry is used as the filling material, there is a risk of scouring between the seawall and the filling material. The filling material does not have any voids, and the filling material does not sink, making it stable against scour action.

"Effects of the Invention" As explained above, the revetment structure and the method for constructing the same according to the present invention include pouring a filling material made of coal ash slurry into the water bottom surrounded by a revetment wall, and hardening the filling material. As a result, the filling material and the revetment wall are integrated, and the following excellent effects can be obtained.

[] Coal ash slurry, which becomes sticky when it contains excessive moisture, was used as the filling material, so the seawall structure with this structure has excellent strength and stability against vibrations caused by waves and earthquakes. becomes.

[] Since the specific gravity of the coal ash slurry used as the filling material, especially in water, is very small, the total weight of the filling material inside the seawall structure should not increase, and the pressure applied to the seawall wall should be small. I can do it. Therefore, the revetment wall can also be made thin, and the amount of revetment wall used can be reduced. Furthermore, considering that coal ash is a low-cost waste generated from thermal power plants, etc., the construction cost required to construct the seawall structure of this invention is significantly greater than that of conventional ones. It will be reduced to.

[] When fluid coal ash slurry is poured into the water bottom as a filling material, the coal ash slurry fills every corner of the inside of the revetment structure, so the revetment wall and the filling material are completely separated. Unify. moreover,
The strength of the entire seawall body having this structure can be maintained constant without variation. In particular, according to the present invention, the revetment wall is provided with an integration means for increasing the adhesion area with the filling material and improving the integration force between the filling material and the revetment wall. Even when the stickiness of the coal ash slurry used as a filler material is low, it is possible to ensure sufficient integration power with the revetment wall. In this case, if the integration means is the bottom slab, the filling material will also adhere to the surface of the bottom slab and become integrated, compared to sticking only to the inner wall surface of the revetment wall and integrating it. The ability to integrate the filler material and the seawall wall increases as the adhesive area increases. In addition, when the integration means is a protrusion provided on the inner wall surface of the revetment wall, the presence of this protrusion not only increases the adhesion area between the filling material and the revetment wall, but also It enters into the inside of the filling material and joins with it, and has the effect of increasing the integration force between the filling material and the revetment wall.

In addition, after the filling material made of coal ash slurry is deaerated, the filling material is placed inside the seawall surrounded by the sea wall, so the coal ash slurry is placed underwater. In this case, the air bubbles do not degas from the coal ash slurry in water, and therefore, the air bubbles
There is no possibility of contamination of the seawall construction area caused by SS being dispersed in the water.

Furthermore, when pouring the filler material, it is passed through a transport pipe with a discharge port located near the water bottom surrounded by the seawall, and is deposited on the bottom of the water. The discharge port is immediately buried in the slurry that has been sequentially discharged and deposited, and as a result, new slurry can be discharged quickly into the slurry that has already been deposited, and as a result, the slurry It is possible to prevent as quickly as possible the deterioration of physical properties after solidification due to deterioration due to contact and mixing with water.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a revetment structure having the revetment structure of the present invention, FIG. 2 is a schematic configuration diagram showing an apparatus used in the method of constructing a revetment structure of the present invention, and FIG. FIG. 2 is a schematic explanatory diagram showing another example of a seawall structure having a seawall structure according to the present invention. 1, 16...Revetment structure, 3...Caisson (revetment wall), 4...Filling material (coal ash slurry), I...
Coal ash, B...water, S...slurry (coal ash slurry), 14...transport pipe, 15...discharge port, 17
...Steel plate cell (revetment wall).

Claims (1)

[Scope of Claims] 1. A filling material made of coal ash slurry is placed inside a wall surrounded by a revetment wall, and the filling material is hardened to integrate the filling material and the revetment wall. and the revetment wall is provided with an integration means for increasing the adhesion area between the revetment wall and the filling material and improving the integration force between the revetment wall and the filling material. A seawall structure characterized by 2. The seawall structure according to claim 1, wherein the seawall is a caisson having a bottom plate, and the integrating means is constituted by the bottom plate of the caisson. 3. The seawall structure according to claim 1, wherein the integrating means is constituted by a projection provided on the inner wall surface of the seawall wall. 4 After the filling material made of coal ash slurry is deaerated, the filling material is passed through a transport pipe with a discharge port located near the water bottom surrounded by a seawall, and deposited by pouring it onto the bottom of the water. 1. A method for constructing a seawall wall body, which comprises: integrating the filling material and the seawall wall body by curing the filling material.