JP5557052B2 - Embankment - Google Patents

Description

  The present invention relates to a levee body used for embankments, revetments and the like.

  In recent years, major earthquakes have frequently occurred in Japan, and several major earthquakes are predicted to arrive in the near future. On riverbanks and coastal levees, there are concerns about damage from liquefaction caused by earthquakes and damage from tsunamis. The response is urgent.

There are various types of embankments such as earthen embankments, concrete caisson embankments, and steel walls.
The embankment can be constructed with inexpensive and readily available materials, but the width of the embankment needs to be increased in order to secure the height while maintaining the stability of the embankment, and there is no land necessary for the construction of the embankment. growing.
In addition, when the levee body is destroyed or subsidized due to the infiltration flow of water in the levee body or liquefaction of the foundation ground, or when overflow occurs due to floods in rivers or tsunamis on coastal levee, scouring or sediment runoff As a result, the embankment has weaknesses such as brittle collapse.

In addition, gravity-type embankments such as concrete caisson embankments that are often used in coastal embankments are heavy, so if the foundation ground is soft, it is necessary to improve the foundation ground.
In addition, in the event of a major earthquake, the gravitational levee body may sink or tilt when the foundation ground liquefies, or may be washed away by the wave force when a tsunami occurs, or the foundation ground may be washed. Damage caused by digging / sucking and becoming unstable.

  Other embankments include a method of constructing a dike body using a steel wall (steel wall) such as a steel sheet pile or steel pipe sheet pile, which occupies a small space and can be constructed in a confined area. Since the steel wall is embedded inside, the dam body is less likely to be washed away by wave force or scouring the surrounding ground, and it is difficult to cause brittle fracture. However, if the required wall height increases, steel materials such as steel pipe sheet piles with a very large cross-section will be required, or a pile for reinforcement and stiffening will be added on the back side and connected to this. In some cases, an expensive structure may be required, such as a need for a structure with an increased height, and there is a problem in cost.

In contrast to these dikes, double sheet pile walls have been widely used as temporary structures such as river repairs, dike repairs, and temporary deadlines for harbor revetments. Usually, temporary levee is to be removed when construction is completed, and constructed with inexpensive and readily available materials. Therefore, the earth and sand generated by surrounding construction and dredging are used for filling the double sheet pile deadline. It is common that In addition, since the earth and sand are used for filling, and the strength of the thread can be taken into consideration, it is constructed at a lower cost than the above-mentioned dam body made of only steel walls using a sheet pile (steel sheet pile, steel pipe sheet pile) with a small cross section. it can.
Further, like the above-mentioned bank wall made of steel such as a steel sheet pile or a steel pipe sheet pile, it has a feature of being embedded in the foundation ground, so that the bank body is less likely to flow and brittle fracture is less likely to occur.

  In addition, in the tsunami-stricken areas of the Great East Japan Earthquake, although the height of the levee body is low, a temporary double sheet pile cut-off levee made of earth and sand is used as a padding material, but it retains its structural stability, although it can be sucked out. The case that has been confirmed has been confirmed, and the wall structure using the double sheet pile wall can be considered as a permanent structure.

On the other hand, it is conceivable to effectively use steel slag, for example, as a part of earth levee or revetment when considering the cost of dike, the effective use of resources, the use of recycling, and the like.
Steel slag is a by-product generated in a large amount in the steel manufacturing process, and is roughly divided into blast furnace slag generated when melting or reducing iron ore in a blast furnace and steelmaking slag generated in the steel making process of refining iron. Furthermore, blast furnace slag is divided into slowly cooled slag and granulated slag depending on the cooling method. Of these, granulated slag is a vitreous and granular steel slag that has been rapidly cooled, such as by injecting pressurized water into the molten slag.

  Since these steel slags are produced in large quantities, they can be obtained relatively inexpensively and in large quantities. Therefore, concrete cement materials and aggregates, road base materials are used as recycled materials according to their characteristics and properties. In addition, it has come to be used as a backfill material for harbor structures (for example, see Patent Documents 1 and 2 and Non-Patent Document 1).

JP 2011-117275 A Japanese Patent No. 4716474

“Examination of hardening acceleration method and hardening strength evaluation method of granulated blast furnace slag”, JSCE Proceedings C (Geosphere Engineering), Vol. 67, no. 1, pp. 145-159, 2011

  By the way, rivers and coastal dikes are almost always assumed to be used semipermanently because of their extremely long life. On the other hand, the double sheet pile wall described above has been used exclusively as a temporary structure that is supposed to be removed so far, and there are also concerns such as a decrease in yield strength due to corrosion of steel materials, leakage of water, and sucking out and sinking back soil. Therefore, it was very rarely used as the main structure.

In addition, effective utilization of steel slag is expected as described above. In particular, granulated blast furnace slag is granular, has little variation in quality, has latent curing properties, is lightweight, and has a large internal friction angle. Due to its characteristics, high-quality sandy soil has become difficult to obtain, and is expected as an alternative material.
However, due to the following, the application is still limited at present and is not widely used in general.
For example, granulated blast furnace slag hardens over time, resulting in changes in strength and water permeability, but the speed and strength of curing differ depending on the conditions, and the degree of hardening and the strength of development vary depending on the location even within the same site. Therefore, it is difficult to evaluate physical properties as a stable material.
In addition, steel slag is not considered hazardous in a general environment, but the magnesium and calcium components in steel slag are eluted, causing water to become cloudy, and rainwater and other water soaked in steel slag If it flows out later, the water that flows out may show alkalinity.

  The present invention has been made in view of the above circumstances, and by using steel slag as a filling material for double sheet pile walls, it is easy to obtain materials during construction, and even against overflow due to tsunami and flooding An object is to provide a bank body that is tenacious and excellent in durability and economy.

The dam body according to claim 1 is provided with double sheet pile walls that connect sheet piles such as steel sheet piles or steel pipe sheet piles, or combination sheet piles obtained by combining other sheet piles or steel materials to the sheet piles. Heavy sheet pile wall,
A connecting material for connecting two rows of the sheet pile walls constituting the double sheet pile wall;
With steel slag as filling material that is packed between the sheet pile walls of the double sheet pile wall ,
The steel slag as the filling material is filled up to a height below the connecting material, and a filling material that does not harden is filled in the filling material .

In the invention described in claim 1, it is easy to obtain a large amount for filling the bank, and by using relatively inexpensive steel slag, it is possible to easily obtain the material when constructing the bank. Can reduce the cost.
For example, at present, there is a problem that it is not always easy to obtain good-quality sandy soil, but this problem can be solved by using steel slag as a substitute for sandy soil.

In addition, even if the water in contact with the steel slag packed inside becomes cloudy or shows alkalinity, the sheet pile wall constituting the double sheet pile wall has water-stopping properties. Or alkaline water outflow is suppressed.
That is, the steel slag is effectively packed in accordance with the properties of the steel slag by being packed in the double sheet pile wall, and can provide an application suitable for the steel slag.
In addition, in the case of steel slag in the double sheet pile wall, in the unlikely event of consolidation subsidence in soft ground or liquefaction during earthquakes, the hardened steel slag will cause the connecting material and double sheet pile wall to The earth and sand of the head as a filling material that does not harden the upper part (head) of the dam body sinks without being adversely affected, so that it can be absorbed. In other words, the connecting material is not buried in the hardened steel slag, and since the hardened steel slag and the connecting material are separated, the connecting material may be affected even if the hardened steel slag sinks. In addition, the upper part of the double sheet pile wall to which the connecting material is fixed is not affected.

  The dam body according to claim 2 is the invention according to claim 1, wherein the steel slag as filling material is blast furnace slag, blast furnace granulated slag of blast furnace slag, or blast furnace granulated slag and others. It is a mixture with slag.

  In invention of Claim 2, a double sheet pile wall is made into a structure more suitable for a dam body by using blast furnace slag as a filling material of double sheet pile wall, especially blast furnace granulated slag of blast furnace slag. be able to. As mentioned above, blast furnace slag and blast furnace granulated slag are known as blast furnace slag. Of the blast furnace slag, granulated blast furnace slag is granular, has little variation in quality, does not show expansion due to reaction with water, has latent curing properties, is lighter than natural sand, and is good sand. It can be expected to have a large internal friction angle comparable to or better than that of the soil. In addition, it has been confirmed that the effect of granulated blast furnace slag on steel corrosion is not different from that of ordinary soil, and does not adversely affect the sheet pile wall.

Therefore, when blast furnace granulated slag is used as a filling material for double sheet pile walls, it does not expand even when it comes into contact with water. There is no negative effect on the part (in the case of embankment).
As described above, when using a double sheet pile wall for a long period of time, the corrosion of the steel material progresses over time and the cross-section decreases, while the hardening of the granulated blast furnace slag progresses and the strength increases. If it is high, it can be made a structure that can prevent the deterioration of the proof strength due to the corrosion of the steel wall and the sucking and sinking of the filling sand due to pitting corrosion. This ensures a long service life of the levee body.

  In addition, blast furnace granulated slag is a material with small variations in quality, but with regard to latent curability, as described above, there are variations in the curing speed, changes in strength, changes in water permeability, etc. as described above. . For this reason, it is difficult to consider the hardening characteristics and strength at the design stage, but in the short term, there is no problem if the levee body is designed without considering the hardening of the filling material. Specifically, the strength can be supplemented by hardening the filling material against a decrease in yield strength due to corrosion of the sheet pile wall.

In addition, when the ground granulated blast furnace slag is hardened, for example, even if the river overflows or the tsunami on the coast causes a water level that exceeds the dam body and overflows (over the wave) Also, by hardening the slag as the filling material, it is possible to make the structure difficult to receive slag scouring or sucking out.
In addition, since the granulated blast furnace slag as a filling material is lightweight and has a large internal friction angle, it can be expected to reduce earth pressure acting on the double sheet pile wall and to exert a large shear strength as a filling material. The cross section of the steel wall which comprises a double sheet pile wall can be made small.
Moreover, when the foundation ground is soft, the filling of the filling material can be suppressed due to the light weight of the filling material.

In addition, blast furnace chilled slag and steelmaking slag may be latently hardened, and may be lighter than natural sand.Furthermore, expansibility and corrosivity are likely to be similar to blast furnace granulated slag. Even if it is not blast furnace granulated slag, some effects are expected.
Moreover, also when mixing a blast furnace granulated slag and other slag (blast furnace slow-cooled slag and steelmaking slag), the above effects by a blast furnace granulated slag can be acquired depending on mixing ratio. The mixing ratio of other slag is preferably 20% or less, and the type is preferably blast furnace annealed slag.

  The dam body according to claim 3 is the invention according to claim 1 or claim 2, wherein the lower part of the double sheet pile wall is placed on a liquefied ground that is highly likely to be liquefied during an earthquake. The double sheet pile wall is embedded in a non-liquefied ground having a low possibility of liquefying below the liquefied ground.

  In the invention according to claim 3, even when the ground where the double sheet pile wall is placed is liquefied, the double sheet pile wall is embedded below the liquefied ground. Prevents settlement and collapse, and can maintain the top height. Therefore, even in severe conditions such as tsunami hits after liquefaction occurs in the surrounding ground due to the earthquake, the height of the levee body is high due to the wall height of the steel material and the effect of intrusion into the non-liquefied ground. Can be maintained.

If possible, the liquefaction occurrence range can be suppressed by replacing steel slag with a part of the liquefied ground in the double cut-off by the double sheet pile wall. As a result, earth pressure from the liquefied ground acting on the double sheet pile wall and deformation of the sheet pile wall due to it can be reduced, and the necessary steel (sheet pile) cross section can be reduced, resulting in an economical structure. be able to.
Furthermore, in the liquefied ground (liquefied layer), the weight of the soil above it acts on the sheet pile wall as horizontal pressure, so if a lightweight blast furnace granulated slag is used, the sheet pile wall in the liquefied ground It is also possible to reduce the earth pressure strength acting on the steel, and to further enhance the effect.

  According to the present invention, by using steel slag as the filling material for the double sheet pile wall, it is possible to easily obtain the material at the time of building the levee body, overflowing due to tsunami and flooding, and further foundations due to earthquake It is possible to provide a bank body that is tenacious against liquefaction of the ground and that is excellent in durability and economy.

It is a schematic sectional drawing which shows the bank body which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 4th Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 5th Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 6th Embodiment of this invention. It is a schematic sectional drawing which shows the bank body which concerns on 7th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the dam body according to the first embodiment of the present invention includes, for example, a double sheet pile wall 3 placed on the ground 10 in a state in which sheet piles 1 such as steel sheet piles and steel pipe sheet piles are connected in two rows. , A tie rod 4 as a connecting material for connecting the two sheets of sheet pile walls 2 and 2 constituting the double sheet pile 3, and a granulated blast furnace slag 5 packed in a portion cut off by the double sheet pile wall 3. It consists of This levee body is used as, for example, a river embankment or a coastal embankment (a seawall or a breakwater).

  The sheet pile 1 is basically a well-known steel sheet pile or steel pipe sheet pile, but may be a combined sheet pile provided by combining a steel sheet pile or a steel pipe sheet pile with other sheet piles or steel materials. Steel sheet piles include U-shaped, hat-shaped, Z-shaped, H-shaped, and the like, and any type of steel sheet pile can be appropriately selected and used in accordance with these characteristics.

The sheet pile walls 2 and 2 are formed by connecting the above-mentioned sheet piles 1 with the joints and placing them on the ground.
In the example of the present invention, these two rows of sheet pile walls 2 and 2 are arranged substantially parallel to each other. Moreover, the space | interval between these sheet pile walls 1 and the height from the ground are determined according to a condition.

Tie rods 4 as connecting members are arranged at approximately predetermined distances in the length direction along the horizontal direction of the two rows of sheet pile walls 2, 2, and the tie rods 4 connect the two sheet pile walls 2, 2. . A tie wire or the like may be used instead of the tie rod. It is also possible to form a connecting member by providing a partition made of steel sheet piles or the like so as to connect two rows of sheet pile walls and connecting both ends of the partition to the sheet pile walls 2 and 2. At this time, the sheet pile wall constituting the partition wall as the connecting member does not necessarily have to be embedded into the foundation ground, and can be shorter than the sheet pile walls 2 and 2.
Between the two rows of sheet pile walls 2 and 2, blast furnace granulated slag 5 is charged as a filling material, and compacted as necessary.

  In such a dam body, it is easy to construct a dam body (obtain material) by using readily available blast furnace granulated slag 5 instead of high-quality sandy soil that may be difficult to obtain. Can be. Further, when water such as rainwater or seawater comes into contact with the blast furnace granulated slag 5, it is considered that calcium or magnesium compounds are eluted and turbid water or alkaline water is generated. In this state, the two sheets of sheet pile walls are closed, and the above-described turbid water or alkaline water can be prevented from leaking outside the double sheet pile walls. In particular, leakage of turbid water or alkaline water can be suppressed by using a steel sheet pile wall having a high water-stopping property in which steel sheet piles are connected as a sheet pile wall.

  The blast furnace granulated slag 5 is not expandable and does not adversely affect the double sheet pile wall. Moreover, when the double sheet pile wall 3 is provided on the earth wall made of embankment described later, when a large earth pressure acts from the blast furnace granulated slag 5 side, slopes 23 and 24 of embankment are formed, etc. However, in this example, the blast furnace granulation flag 5 does not expand and the adverse effects on the law sections 25 and 25 are not affected. Does not occur.

Moreover, the granulated blast furnace slag 5 is lighter than natural sand, and the earth pressure acting on the double sheet pile wall 3 is reduced. Furthermore, the granulated blast furnace slag 5 can be expected to have an internal friction angle equal to or higher than that of good sandy soil. This can also be expected to reduce the earth pressure acting on the double sheet pile wall 3 and increase the yield strength of the dam body by increasing the shear strength of the padded soil. The cross section of the steel wall which comprises a sheet pile wall can be made small.
In addition, since the granulated blast furnace slag 5 is light as described above, if there is a possibility that the filling material may sink due to the soft ground immediately below the ground surface, it will also be effective in suppressing settlement.

In addition, since the blast furnace granulated slag 5 has latent curability, the earth pressure of the double sheet pile wall 3 is further reduced after the blast furnace granulated slag 5 is cured.
In addition, because the blast furnace granulated slag 5 is latently curable, the blast furnace granulated slag 5 is hardened even if the water level exceeds the embankment and an overflow occurs (even if a wave is applied). If this happens, it will be difficult for scouring and sucking.
Moreover, although the steel material (sheet pile 1) which comprises the double sheet pile wall 3 progresses corrosion over time and a cross-section decreases, conversely, the blast furnace granulated slag 5 progresses hardening and becomes high in strength. The relationship between the two can complement each other's characteristics.

It is also possible to increase the curing rate and its strength by adding additives to the blast furnace granulated slag 5, and by promoting the curing of the filling material made of the blast furnace granulated slag 5, or by increasing the expression strength, This bank can also be made into a more economical and rational structure.
For example, by adding blast furnace slag fine powder, cement, lime, or the like to the granulated blast furnace slag 5, the curing rate and strength can be increased.

  When this embodiment is used for a new levee body, the required levee body height, usable space (the width of the levee body), the size of the cross section of the steel sheet pile, the steel pipe sheet pile, etc. to be used are variously combined. In consideration of the above, an optimal structure can be constructed. Moreover, rationalization of a structure can also be achieved, such as reducing the required cross section of steel materials (sheet pile 1) by considering the hardening rate and its intensity | strength of the blast furnace granulated slag 5 from the beginning as mentioned above.

  As described above, this levee body has the strength and rigidity of the steel material to be used, the width of the double sheet pile wall (the width of the dam body cross section shown in FIG. 1 and the like), and the filling (backfill) range of blast furnace granulated slag 5 It is possible to take various structural forms such as (depth) and consideration of hardening / strength of the granulated blast furnace slag 5. Therefore, various conditions (required height / space, foundation ground conditions,...) Can be handled. In addition, since the width of the levee body can be reduced with respect to the height compared to earthen levee or gravity type wall body, construction can be performed even in a narrow area.

  According to this levee body, it is possible to complement each of the disadvantages of conventional levee bodies, double sheet pile wall bodies, and steel slag made of earthen dykes, concrete walls, and steel walls, and realize a structure that takes advantage of the advantages. Because the double sheet pile wall 3 is embedded in the foundation ground, it is tenacious against tsunami and flood overflow, liquefaction and infiltration of the foundation ground, and can reliably maintain the height of the levee body. A high structure is obtained.

  Furthermore, since blast furnace granulated slag 5 (latent hardenability, internal friction angle, light weight) is applied as the filling material, it is economical by reducing the necessary steel material cross section of the sheet pile 1, and corrosion of steel material over time. -The structure can be made resistant to deterioration, and by-products generated in the steel manufacturing process can be actively used as recycled materials, so that an environment-friendly structure can be realized.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 2, the bank of the second embodiment is obtained by changing the depth of the sheet pile walls 2 and 2 in the bank of the first embodiment and changing the upper portion of the filling material. The other structure is the same as that of the first embodiment.

In the second embodiment, the ground on which the levee body is installed is a liquefied ground 10a that is highly likely to be liquefied. When the sheet pile walls 2 and 2 are placed on the liquefied ground 10a which may be liquefied at the time of the earthquake, the depth of the sheet pile walls 2 and 2 is below the liquefied ground 10a and is liquid at the time of the earthquake. The non-liquefied ground 10b, which has a low possibility of being liquefied, is incorporated.
Further, when filling the blast furnace granulated slag 5 b into the closed double sheet pile wall 3, the height of the blast furnace granulated slag 5 b is set slightly below the tie rod 4. On the upper side of the granulated blast furnace slag 5b, earth and sand 6 is filled as an intermediate filling material that does not harden as an intermediate filling material that is not hardened.

In such a levee body, even when the liquefied ground 10a is liquefied, the sheet pile walls 2 and 2 are rooted to the non-liquefied ground 10b deeper than the liquefied ground 10a. Can be prevented and the height of the top can be maintained.
Therefore, the dam body maintains the top edge height due to the wall height of the steel material (sheet pile 1) and the effect of piercing even under severe conditions such as the tsunami attacking after liquefaction occurs in the surrounding ground due to the earthquake. it can.

  In addition, the blast furnace granulated slag 5b in the double sheet pile wall 3 is hardened. At this time, the hardened blast furnace granulated slag is hardened due to consolidation settlement of the soft ground or liquefaction of the ground during an earthquake. There is a possibility that 5b sinks to some extent. At this time, if the hardened blast furnace granulated slag 5b surrounds the tie rod 4, the tie rod 4 may be deformed by subsidence, or the upper parts of the sheet pile walls 2 and 2 to which the tie rod 4 is fixed may be deformed. There is. However, in this embodiment, since the hardened blast furnace granulated slag 5b only reaches the lower side of the tie rod 4, when the blast furnace granulated slag 5b sinks, the surroundings of the tie rod 4 above the blast furnace granulated slag 5b Although the earth and sand 6 also sinks, since the earth and sand 6 is not hardened, the shape of the earth and sand 6 changes with respect to the sinking of the hardened blast furnace granulated slag 5b, so that a large load is not applied to the tie rod 4. And deformation of the sheet pile walls 2 and 2 can be prevented.

Next, a third embodiment of the present invention will be described.
As shown in FIG. 3, the bank body of the third embodiment changes the depth of the sheet pile walls 2 and 2 in the bank body of the first embodiment and the depth at which the filling material is filled. The other structure is the same as that of the first embodiment.
The ground where the bank body in the third embodiment is installed is the liquefied ground 10a as in the second embodiment, and the depth of the sheet pile walls 2, 2 is below the liquefied ground 10a. The liquefied ground 10b is rooted.

  In addition, after placing the sheet pile walls 2 and 2 by a press-fitting machine or a vibro hammer, the sheet pile walls 2 and 2 are used as retaining walls, and at least a part of the liquefied ground 10a cut off by the sheet pile walls 2 and 2 is excavated. To remove. The excavation depth at this time is deeper than the groundwater level 11. After excavation, the ground granulated blast furnace slag 5c is inserted between the sheet pile walls 2 and 2 and is compacted. Thereby, a part of the liquefied ground 10a of the part cut off by the sheet pile walls 2 and 2 is replaced with the blast furnace granulated slag 5c.

In such a dam body, as in the second embodiment, the sheet pile walls 2 and 2 are embedded up to the non-liquefied ground 10b, so that a tsunami hits after the surrounding ground is liquefied by an earthquake. Even under such severe conditions, the height of the levee body can be maintained by the wall height of the steel material and the effect of piercing.
Moreover, the generation | occurrence | production range of liquefaction can be suppressed by replacing a part of liquefaction ground 10b in the double deadline by the sheet pile walls 2 and 2 with the blast furnace granulated slag 5c.
Thereby, reduction of the earth pressure which acts on the double sheet pile wall 3 in a liquefied ground can be aimed at. In the liquefied layer liquefied at the time of the earthquake, the weight of the soil (filling material) above it acts on the sheet pile walls 2 and 2 as horizontal pressure, but the sheet pile is generated by suppressing the liquefaction range Since the effect of reducing stress and displacement can be expected, the cross section of the steel material necessary for the sheet pile 1 can be reduced, and an economical structure can be obtained.

Next, a fourth embodiment of the present invention will be described.
As shown in FIG. 4, the bank body of the fourth embodiment is an application of the bank body of the first embodiment to the earthwork, and the structure other than that applied to the earth bank is the same as that of the first embodiment. It has become.

  In the bank body of 4th Embodiment, the double sheet pile wall 3 which consists of two rows of sheet pile walls 2 and 2 is constructed | assembled by connecting the sheet pile 1 to the earth bank 21 which is the embankment by the existing embankment. The two rows of sheet pile walls 2 and 2 are connected by a tie rod 4. The height of the two rows of sheet pile walls 2 and 2 is substantially the same as the height of the top end 22 of the earth wall 21. Using this double sheet pile wall 3 as a retaining wall (double deadline wall), for example, excavating earth and sand to the bottom of the earth levee, and blast furnace granulation as a filling material in the excavated space in the double sheet pile wall 3 Slag 5 is charged and compacted. From the above, the levee body of this embodiment has a structure in which the existing earth dyke 21 is reinforced, but the same structure can be applied not only to the existing earth dyke but also to a new one. It is. The structure of the present invention can also be applied to the case of a newly installed levee when the earth levee is preferable in consideration of the hydrophilicity of the levee body and consideration of organisms / vegetation.

The earth wall 21 has a substantially trapezoidal cross section perpendicular to the length direction, and a flat top end 22 at the center and a slope 23 inclined downward on the right and left sides (inside and outside) on the upper surface side. 24 is formed. Here, the portions where the slopes 23 and 24 of the levee body are formed are referred to as law portions 25 and 25. When the width of the double sheet pile wall 3 is substantially the same as the width of the top end 22, the bank body has a structure in which the normal portions 25 are added to the left and right of the bank body of the first embodiment.
In 4th Embodiment, the same effect as 1st Embodiment can be provided to the earth dyke 21, and the earth dyke 21 can be reinforced.

Next, a fifth embodiment of the present invention will be described.
As shown in FIG. 5, the bank body of the fifth embodiment is obtained by changing the depth of sheet pile walls 2 and 2 in the bank body of the fourth embodiment, and other structures are the same as those of the fourth embodiment. It has become the same.
In the fifth embodiment, as in the second embodiment, the sheet pile walls 2 and 2 are rooted to the non-liquefied ground 10b below the liquefied ground 10a.
In the fifth embodiment, it is possible to obtain the same effects as in the case where the sheet pile walls 2 and 2 are rooted to the non-liquefied ground in the second embodiment in the existing earth wall 21.

Next, a sixth embodiment of the present invention will be described.
As shown in FIG. 6, the bank of the sixth embodiment is obtained by changing the state of the filling material in the bank of the fifth embodiment, and other structures are the same as those of the fifth embodiment. Yes.
In the sixth embodiment, when excavating between the two rows of sheet pile walls 2 and 2, the depth is not deeper than the bottom of the earth wall 21 but deeper than that. At this time, a part of the liquefied ground 10a is excavated. That is, the earth and sand are excavated to a depth reaching the liquefied ground 10a.

Next, blast furnace granulated slag 5d is introduced between the two rows of sheet pile walls 2 and 2, and is compacted as necessary. At this time, a part of the earth and sand of the liquefied ground 10a is replaced with the blast furnace granulated slag 5d.
Similarly to the case of the second embodiment, the height position of the granulated blast furnace slag 5d that is packed between the two rows of sheet pile walls 2 and 2 is slightly lower than the tie rod 5. The earth and sand 6 is thrown into the upper side of the blast furnace granulated slag 5d as the filling material and compacted. At this time, the tie rod 4 is buried in the earth and sand 6. The earth and sand 6 is obtained by filling back the excavated earth and sand between the two rows of sheet pile walls 2 and 2.

  In the dam body of the sixth embodiment, the same effect as when the upper part of the filling material is the earth and sand 6 in the second embodiment, and the liquefied ground 10a inside the double sheet pile wall 3 in the third embodiment. The same effect as when a part of the earth and sand is replaced with the blast furnace granulated slag 5c can be obtained.

In each of the above-described embodiments, for example, a water permeable sheet pile in which a through hole is formed may be used as the sheet pile, thereby enabling the groundwater to flow.
Moreover, the sheet pile walls 2 and 2 do not necessarily need to be connected (joints are fitted) over the whole, and may be provided with locations where adjacent sheet piles are not connected by a joint. In order to prevent the uncured filled slag from flowing out from this non-connected portion, when the non-connected portion is placed so as to wrap adjacent sheet piles, or when there is a gap in the non-connected portion In addition, another sheet pile may be placed in parallel in the vicinity so as to close this section. In this way, it is possible to provide a structure that maintains the flow of groundwater by providing non-connected portions of the joints at appropriate intervals.
After the slag as the filling material has hardened, there is no outflow from the unconnected part, and the effect of reinforcing the unconnected part of the steel wall, which may be a structural weakness, can be obtained. The stability of the whole body is improved.

Next, a seventh embodiment of the present invention will be described.
As shown in FIG. 7, the levee body of the seventh embodiment is a dam body of the second embodiment provided with a mound-like earth dyke 21, and the other structure is the same as that of the second embodiment. ing.
The earth wall 21 does not necessarily have to be built up to the upper surface side of the bank body 3 as in the fourth to sixth embodiments. If the projecting portion of the levee body 3 is reduced by the earth dyke 21, it will be structurally advantageous as a dam body. That is, by reducing the height of the levee protruding above the ground, it is possible to improve the proof strength of the levee when an external force is applied to the dam by a tsunami or flood. Moreover, when liquefaction generate | occur | produces, the overlay pressure above it acts on a sheet pile wall in the liquefaction ground 10a as a horizontal pressure. Within the double sheet pile deadline, the weight of the padding material up to the top edge above the liquefied layer acts as a horizontal pressure, trying to push the sheet pile outward, but on the other hand, the mound outside the double sheet pile deadline The weights of the earth-like embankments 23 and 24 act as counterweights and act to suppress deformation of the sheet pile wall 2. In addition, although the earth dyke 21 was drawn in substantially trapezoid shape in FIG. 7, the earth dyke 21 should just be formed so that a part of protrusion part may be hidden.

  In the fourth to seventh embodiments described above, the slopes 23 and 24 of the earth wall 21 may be constructed by blast furnace granulated slag. In this case, when the granulated blast furnace slag is hardened due to latent curability, it is possible to prevent the method part 25 from being scoured or washed away due to overflow.

In addition, when a new earth wall 21 having a double sheet pile wall 3 is newly provided, a layer in which blast furnace granulated slag is spread between the foundation ground surfaces at the bottom of the law sections 25 and 25 may be provided. In the case of such a configuration, even if the scouring due to overflow occurs and the law sections 25 and 25 are washed away, the presence of a layer of hardened blast furnace granulated slag is more than that. Deeper scouring of the ground can be prevented, and large-scale scouring that impairs the stability of the levee body can be prevented.
Moreover, in the dam body of 1st Embodiment to 3rd Embodiment, you may arrange | position so that a blast furnace granulated slag may be spread | laid on the ground surface of the inner side and outer side of a dam body. In this case, the same effect as described above can be obtained.

  As the filling material, blast furnace granulated slag among steel slags is most likely to be the best, but blast furnace slow-cooled slag and steelmaking slag may be used. Moreover, you may use the mixture of blast furnace granulated slag and at least one steel slag of blast furnace slow cooling slag and steelmaking slag as a filling material. In addition, steel slag contains various earth and sand (can be earth, sand, stone, excavated earth, dredged earth) and additives for promoting hardening (eg blast furnace slag fine powder, cement and lime). May be.

1 sheet pile (steel sheet pile, steel pipe sheet pile, combination sheet pile)
2 Sheet pile wall 3 Double sheet pile wall 4 Tie rod (connecting material)
5 Blast Furnace Granulated Slag (Slag, Blast Furnace Slag)
6 Earth and sand (filling material that does not harden)
10 Ground 10a Liquefaction ground 10b Non-liquefaction ground

Claims (3)

A double sheet pile wall provided with a double sheet pile wall connecting a sheet pile such as a steel sheet pile or a steel pipe sheet pile, or a combination sheet pile made by combining other sheet piles and steel materials to the sheet pile;
A connecting material for connecting two rows of the sheet pile walls constituting the double sheet pile wall;
With steel slag as filling material that is packed between the sheet pile walls of the double sheet pile wall ,
The embankment characterized in that the steel slag as the filling material is filled up to a height lower than the connecting material, and an filling material that does not harden is filled on the slag .   The dyke according to claim 1, wherein the steel slag as the filling material is blast furnace slag, blast furnace granulated slag of blast furnace slag, or a mixture of blast furnace granulated slag and other slag. body.   When the lower part of the double sheet pile wall is placed on a liquefied ground that is highly likely to liquefy during an earthquake, the double sheet pile wall is less likely to liquefy below the liquefied ground. The embankment according to claim 1 or 2, wherein the embankment is embedded in the ground.

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