JP2008190200A - Precast retaining wall and construction method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retaining wall which has a simple structure and can be increased in bulk. <P>SOLUTION: A precast retaining wall 1 is disposed on a bank 5, and is composed of minimum component units of a foundation precast panel 9 and a retaining wall precast panel 11 connected to the upper surface of the foundation precast panel 9. The precast retaining wall 1 also includes a bracing block 13 that is disposed to connect the foundation precast panel 9 to the retaining wall precast panel 11. A slot 17 is formed on the upper surface of the body 15 of the foundation precast panel 9, and a projection 27 is formed on an end face of the body 25 of the retaining wall precast panel 11. The projection 27 corresponds in shape to the slot 17 of the foundation precast panel 9. Hence the projection 27 of the retaining wall precast panel 11 is engaged with the slot 17 to construct the precast retaining wall 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an existing coastal dike against a rise in water level due to a tsunami, a storm surge, and the like, a precast retaining wall used for raising a revetment, and a method for constructing a precast retaining wall.

  In recent years, the water level (tide level) rise due to global warming, the power of typhoons, and the actual behavior of tsunamis along the coast are becoming clearer.

  For this reason, it is necessary to take some measures for coastal revetments and dikes that are behind important structures and facilities to prevent secondary disasters caused by inundation and drifting due to rising water levels.

  In particular, in the case of a tsunami, secondary damage may be increased by destroying important structures by drifting harbours, ships, driftwood, automobiles, etc. existing inside and outside the coastal area.

  As a countermeasure against such a tsunami or a drifting object accompanying the tsunami, there is a case where a retaining wall is constructed above the existing revetment to raise the revetment (Patent Document 1).

  On the other hand, there is also known a so-called storage-type structure in which an overflow prevention structure is provided in the revetment and these structures are exposed to the ground to raise the revetment only when the water level rises.

  As such a structure, for example, a wall that rises in accordance with the rise of the water level on the front side is provided in the revetment or embankment, and this wall rises on the top of the top in accordance with the rise of the water level and forms a retaining wall. There exists a structure (patent document 2) which raises the height of this.

Alternatively, a hose member is provided inside the revetment or embankment, and water is injected into the hose member and inflated as the water level rises on the front surface, thereby forming a retaining wall to raise the revetment (Patent Document 3) )and so on.
JP 2006-124910 A JP-A-61-49013 JP-A-8-284139

  However, when the retaining wall is constructed on the upper part of the existing revetment, it will be a large-scale facility, so it will take space and labor for rebar, formwork assembly, concrete placement, etc. There are various restrictions such as securing and reinforcing the revetment.

  In addition, as a retaining wall, a thick concrete wall is constructed at a higher position than the revetment and embankment, so the landscape deteriorates and the use of land is affected.

  On the other hand, in the case of a storage-type revetment raising structure, if the revetment itself is damaged by an earthquake before the tsunami arrives, the raising structure may be damaged and not operate normally.

  Furthermore, when a storage-type raising structure is installed on an existing revetment, the existing revetment will be significantly modified and strengthened, so the cost and labor required to construct these facilities over a long extension line will be enormous. Become.

  The present invention has been made in view of such problems, and an object thereof is to provide a retaining wall that has a simple structure and can be reliably raised.

  In order to achieve the above-described object, the first invention is a base precast plate laid on a revetment or embankment and having a first engaging portion on the upper surface, and an end surface engaged with the first engaging portion. A retaining wall precast plate having a second engaging portion.

The material constituting the basic precast plate and / or the retaining wall precast plate is concrete having a compressive strength of 100 to 250 N / mm ² and a bending tensile strength of 10 to 40 N / m ² .
The foundation precast plate has a first connection structure connected to the other foundation precast plate, and the retaining wall precast plate has a second connection structure connected to the other retaining wall precast plate. .

  The retaining wall precast plate may be provided with a gap between the first connection structures when connected to the other basic precast plate, and the gap may be filled with a water-stopping filler. .

The precast retaining wall may further include a sheath tube provided inside the retaining wall precast plate, and a wire provided in the sheath tube and connecting the plurality of precast plates.
A protrusion may be provided on the bottom surface of the basic precast plate, and a scour preventing mat provided around the basic precast plate may be further provided.

  The second invention includes a step (a) of connecting and laying a plurality of foundation precast plates on a revetment or embankment, and an end face of a retaining wall precast plate on a first engagement portion provided on the foundation precast plate. A method for constructing a precast retaining wall, comprising: a step (b) of engaging a second engaging portion provided; and a step (c) of connecting side surfaces of the retaining wall precast plate. .

  The step (c) may be a step of providing a sheath pipe inside the retaining wall precast plate and connecting adjacent retaining wall precast plates through a wire in the sheath tube.

In the first invention, the precast retaining wall has a basic precast plate having a first engaging portion on the upper surface, and a retaining wall precast plate having a second engaging portion engaged with the first engaging portion on the end surface. It has.
Therefore, the structure of the precast retaining wall is simple and can be reliably raised.

In the first invention, the material constituting the basic precast plate and / or the retaining wall precast plate is concrete having a compressive strength of 100 to 250 N / mm ² and a bending tensile strength of 10 to 40 N / m ² .
Therefore, the basic precast plate and / or the retaining wall precast plate are lightweight and thin, and are easy to construct and remove.

  According to the present invention, it is possible to provide a retaining wall that has a simple structure and can be reliably raised.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a perspective view showing an embankment 5 provided with a precast retaining wall 1 according to the first embodiment, FIG. 2 is a diagram showing a minimum structural unit of the precast retaining wall 1, and FIG. It is AA sectional drawing of b).

  4 is a diagram showing a basic precast plate 9 of the precast retaining wall 1, FIG. 5 is a diagram showing a retaining wall precast plate 11 of the precast retaining wall 1, and FIG. 6 is a diagram showing a holding block 13 of the precast retaining wall 1. is there.

  Further, FIG. 7 is an enlarged cross-sectional view showing a connecting portion between the retaining wall precast plates 11.

As shown in FIG. 1, a bank 5 is provided on the sand beach 3.
A precast retaining wall 1 is provided on the embankment 5 to raise the embankment 5.

  As shown in FIGS. 2 and 3, the minimum structural unit of the precast retaining wall 1 includes a basic precast plate 9 and a retaining wall precast plate 11 engaged with the upper surface of the basic precast plate 9.

  Further, the precast retaining wall 1 further includes a holding block 13 provided so as to connect the basic precast plate 9 and the retaining wall precast plate 11.

The basic precast plate 9 is a member that becomes a base of the precast retaining wall 1 and has a flat plate-like main body 15 as shown in FIG.
A groove portion 17 as a first engagement portion is provided on the upper surface of the main body 15.

  Further, the side surface of the main body 15 is provided with a convex portion 19a and a groove portion 19b as a first connection structure. The shape of the groove 19b corresponds to the shape of the convex portion 19a.

Furthermore, the main body 15 is provided with through holes 21a, 21b, 21c, and 21d so as to penetrate the lower surface from the upper surface.
Further, as shown in FIGS. 3 and 4, shear keys 38 a and 38 b that are band-like protrusions are provided on the lower surface of the main body 15.

The groove portion 17 is used when the basic precast plate 9 is engaged with the retaining wall precast plate 11.
The convex portion 19 a and the groove portion 19 b are used when the basic precast plate 9 is connected to another basic precast plate 9.
The through holes 21 a, 21 b, 21 c, 21 d are used when the basic precast plate 9 is laid on the bank 5.

The shear keys 38a and 38b prevent the basic precast plate 9 from moving during a tsunami.
The details of the operation of these members will be described later.

The retaining wall precast plate 11 is a member that receives a tsunami or a drifting object in the case of a tsunami, and has a flat plate-like main body 25 as shown in FIG.
On the lower end surface of the main body 25, a convex portion 27 as a second engaging portion is provided.
The shape of the convex portion 27 corresponds to the shape of the groove portion 17 of the basic precast plate 9.

  On the side surface of the main body 25, a convex portion 29a and a groove portion 29b are provided as a second connection structure. The shape of the groove portion 29b corresponds to the shape of the convex portion 29a.

Further, evacuation steps 33 a, 33 b, 33 c, and 33 d are provided on the front side of the planar portion of the main body 25.
For example, the uppermost step of the evacuation step may be continuously provided along the extending direction of the retaining wall, so that the effect of returning waves against the tsunami that goes up on the revetment may be enhanced.

Further, through holes 31a, 31b, 31c, and 31d are provided through the flat portion of the main body 25.
In addition, as shown in FIG. 3, the shape of the through holes 31c and 31d is reduced in diameter from the front side to the back side of the flat portion. The same applies to the through holes 31a and 31b.

  On the other hand, as shown in FIGS. 3 and 5, a sheath tube 35 is provided inside the main body 25 so as to be substantially parallel to the end surface, and a wire 37 is provided in the sheath tube 35.

The convex portion 27 is used when the retaining wall precast plate 11 is engaged with the basic precast plate 9.
The convex portion 29a, the groove portion 29b, the sheath tube 35, and the wire 37 are used when the retaining wall precast plate 11 is connected to another retaining wall precast plate 11. The wire 37 is a high tension wire.

The through holes 31a, 31b, 31c, and 31d are used when the retaining wall precast plate 11 is engaged with the basic precast plate 9, and also used as a drain port when a banking is provided on the back.
The evacuation steps 33a, 33b, 33c, and 33d are used for evacuation during a tsunami.
The details of the operation of these members will be described later.

  Here, the materials constituting the foundation precast plate 9 and the retaining wall precast plate 11 are required to have a weather resistance that can withstand the action of fluid force due to the tsunami overflow and the collision of drifting objects and can withstand waves, wind and rain.

As such a material, it is desirable to use ultra high strength fiber reinforced concrete which does not use a reinforcing bar and has a compressive strength of 100 to 250 N / mm ² and a bending tensile strength of 10 to 40 N / m ² .

By using such a material, the basic precast plate 9 and the retaining wall precast plate 11 can have a high strength, a thin wall, and a compact structure.
Moreover, since no reinforcing bars are used, there is no risk of corrosion due to rainwater or seawater.
In addition, the height of the retaining wall precast plate 11 is about 1 to 2 meters.

On the other hand, as shown in FIG. 6, the stay block 13 has a plate shape.
The reserve block 13 is a member that reinforces the engagement between the basic precast plate 9 and the retaining wall precast plate 11, and the same material as the basic precast plate 9 and the retaining wall precast plate 11 is used.

  The precast retaining wall 1 is formed by engaging the convex portion 27 of the retaining wall precast plate 11 with the groove portion 17 of the basic precast plate 9.

The retaining wall precast plate 11 is provided substantially perpendicular to the basic precast plate 9, but may be slightly inclined to the land side as shown in FIG.
By tilting in this way, when the tsunami collides with the retaining wall precast plate 11, the impact force is alleviated and the vertical component of the impact force acts downward, so the basic precast plate 9 moves due to the tsunami. Can be prevented.

Further, a groove portion corresponding to the shape of the convex portion 27 may be provided on the upper end surface of the retaining wall precast plate 11.
By adopting such a structure, the retaining wall precast plates 11 can be connected to each other upward, and further raising the height is possible.

  The holding block 13 is provided with a groove or a local ridge hole (not shown) in the basic precast plate 9 or the retaining wall precast plate 11 in advance, and the basal projections 14a and 14b of the holding block 13 are fitted into the basic precast plate 13. Connected to plate 9 and retaining wall precast plate 11.

As shown in FIG. 1, the precast retaining wall 1 may have a structure in which a plurality of basic precast plates 9 and a plurality of retaining wall precast plates 11 are connected.
In this case, the convex part 19a and the groove part 19b of the adjacent basic precast plate 9 are connected.
Moreover, the convex part 29a and the groove part 29b of the adjacent retaining wall precast plate 11 are connected.

At this time, as shown in FIG. 7A, a gap 39 is generated between the retaining wall precast plates 11.
Since the gap 39 is generated, the precast retaining wall 1 can be connected in a curved shape in accordance with the shape of the dyke 5 even if the dyke 5 is curved.

  In addition, since the gap 39 is generated, the retaining wall precast plates 11 are equivalent to each other by the gap 39 with respect to the local force caused by the uneven settlement of the levee 5 due to liquefaction at the time of an earthquake or the collision of drifting objects due to the tsunami. They can move relative to each other.

Therefore, the local force generated in the precast retaining wall 1 can be dispersed and the destruction of the precast retaining wall 1 can be prevented.
The basic precast plate 9 also has the same effect because a gap is generated in the connecting portion.

Further, as shown in FIG. 7B, a filler 41 for water stop may be provided in the gap 39.
By providing the filler 41, seawater can be prevented from flowing out of the gap 39 during a tsunami.

When the retaining wall precast plates 11 are connected to each other, not only the convex portions 29a and the groove portions 29b are connected, but also the wires 37 are used as shown in FIG. Connect together.
In addition, the connection effect may be further enhanced by making the connecting wire 37 long and connecting the wire 37 inside or outside the bank of the precast retaining wall 1.

With such a structure, the plurality of retaining wall precast plates 11 share the impact force against the tsunami.
At this time, in order to provide a function of allowing a relative displacement by providing a gap between adjacent precast plates, it is desirable to connect the wires 37 so as not to give prestress.

Therefore, the local force generated in the retaining wall precast plate 11 can be dispersed, and the retaining wall precast plate 11 can be prevented from partially falling off the basic precast plate 9.
For the wire 37, it is desirable to use a material such as an aramid fiber that has high elasticity and tensile strength and is resistant to corrosion.

Next, a procedure for providing the precast retaining wall 1 on the bank 5 will be described.
First, the basic precast plate 9 is laid on the dike 5.
At this time, when a plurality of basic precast plates 9 are provided, after the plurality of basic precast plates 9 are laid on the bank 5, the convex portions 19a and the groove portions 19b of the adjacent basic precast plates 9 are connected.

In laying, hooks (not shown) are hooked in the through holes 21a, 21b, 21c, 21d of the foundation precast plate 9, and the foundation precast plate 9 is lifted using a crane (not shown) and laid at a predetermined position.
The foundation precast plate 9 may be laid on the bank 5 manually.

  Next, the precast retaining wall 1 is formed by engaging the convex portion 27 of the retaining wall precast plate 11 with the groove portion 17 of the basic precast plate 9.

At this time, when a plurality of retaining wall precast plates 11 are provided, after the basic precast plate 9 and the retaining wall precast plate 11 are engaged, the convex portions 29a and the groove portions 29b of the adjacent retaining wall precast plates 11 are connected.
Further, the plurality of retaining wall precast plates 11 are connected through the wires 37 into the sheath tube 35.

  When the retaining wall precast plate 11 is engaged with the basic precast plate 9, hooks (not shown) are hooked in the through holes 31a, 31b, 31c, 31d of the retaining wall precast plate 11, and a crane (not shown) is used. The retaining wall precast plate 11 is lifted, moved to a predetermined position, and engaged with the basic precast plate 9.

  The movement of the retaining wall precast plate 11 and the engagement with the basic precast plate 9 may be performed manually.

In this way, the precast retaining wall 1 is constructed on the bank 5.
In addition, after the precast retaining wall 1 is constructed, the back of the precast retaining wall 1 may be filled.

At that time, the retaining wall precast plate 11 can be used as an embedded form by laying and rolling a mixture of poor blended cement into the embankment.
Moreover, when embankment is provided, the through-holes 31a, 31b, 31c, 31d of the retaining wall precast plate 11 are used as drainage ports.

  In such a structure, seawater may enter through the through holes 31a, 31b, 31c, and 31d during the tsunami, but the shape of the through holes 31a, 31b, 31c, and 31d is from the front side of the plane portion. Since the diameter is reduced toward the back side, seawater hardly flows to the back.

In addition, after the precast retaining wall 1 is constructed on the dike 5, the dike 5 below the through holes 21a, 21b, 21c and 21d of the foundation precast plate 9 is excavated, and concrete is placed in the excavated hole to project May be formed.
By forming such protrusions, the protrusions have the same effect as the shear keys 38a and 38b.

In addition, when removing the precast retaining wall 1 from the embankment 5, the procedure reverse to the above procedure is performed.
That is, the protruding portion 27 of the retaining wall precast plate 11 is pulled out from the groove portion 17 of the foundation precast plate 9 to remove the retaining wall precast plate 11, and then the foundation precast plate 9 is removed from the bank 5.

  At this time, when a plurality of precast plates 9 and a plurality of retaining wall precast plates are connected to each other, after the mutual connection is released, the convex portion 27 of the retaining wall precast plate 11 from the groove portion 17 of the basic precast plate 9. To remove the retaining wall precast plate 11.

Here, the retaining wall precast plate 11 is easy to attach and remove because the convex portion 27 is only engaged with the groove portion 17.
Therefore, the precast retaining wall 1 is easy to construct and remove.

  In addition, when a plurality of basic precast plates 9 and retaining wall precast plates are connected to each other, each is simply connected by a groove, a convex portion, and a wire, so that attachment and removal are easy.

Further, as a material constituting the basic precast plate 9 and the retaining wall precast plate 11, ultrahigh strength fiber reinforced concrete having a compressive strength of 100 to 250 N / mm ² and a bending tensile strength of 10 to 40 N / m ² without using reinforcing bars is used. Since the basic precast plate 9 and the retaining wall precast plate 11 are lightweight and thin, they are easy to construct and remove.

  Furthermore, since the foundation precast plate 9 and the retaining wall precast plate 11 do not use reinforcing bars, the through holes 21a, 21b, 21c, 21d, 31a, 31b, 31c, 31d can be provided at arbitrary positions.

Next, the operation of the precast retaining wall 1 when a tsunami occurs will be described.
FIG. 8 is a view showing the vicinity of the embankment 5 when a tsunami occurs, and FIG. 9 is a longitudinal sectional view of the precast retaining wall 1 of FIG.

  As shown in FIG. 8, when a tsunami 40 is generated by an earthquake, the tsunami 40 approaches the embankment 5.

At this time, as shown in FIG. 9, the retaining wall precast plate 11 of the precast retaining wall 1 receives the impact force of the tsunami 40 and prevents seawater from flowing out to the back.
Further, the retaining wall precast plate 11 receives the drifting material 51 and prevents the drifting material 51 from flowing out to the back and colliding with the structure or the like on the back.

  Here, unlike the storage-type retaining wall, the precast retaining wall 1 does not have an operating portion, so that the embankment 5 can be reliably raised, and acts reliably in the event of an earthquake or tsunami.

  Further, the shear keys 38 a and 38 b resist the impact force of the tsunami 40, thereby preventing the basic precast plate 9 from moving.

  A person who is closer to the sea 7 than the precast retaining wall 1 can escape to the back of the precast retaining wall 1 through the evacuation steps 33a, 33b, 33c, and 33d before the tsunami 40 arrives.

Thus, according to the first embodiment, the precast retaining wall 1 has the foundation precast plate 9 and the retaining wall precast plate 11, and the convex portion 27 of the retaining wall precast plate 11 is formed in the groove portion 17 of the foundation precast plate 9. Are engaged.
Therefore, the structure of the precast retaining wall 1 is simple, and the embankment 5 can be reliably raised.

Further, according to the first embodiment, the material constituting the foundation precast plate 9 and the retaining wall precast plate 11 has a compressive strength of 100 to 250 N / mm ² without using a reinforcing bar, and a bending tensile strength of 10 to 40 N / m. ^2. Ultra high strength fiber reinforced concrete.

  Therefore, the basic precast plate 9 and the retaining wall precast plate 11 are light and thin, and can be easily constructed and removed from the dike 5.

Furthermore, according to the first embodiment, when a plurality of basic precast plates 9 and a plurality of retaining wall precast plates 11 are connected, a gap is generated in the connecting portion.
Therefore, the precast retaining wall 1 can be connected even if the bank 5 is curved.

  In addition, due to the formation of gaps, the foundation precast plates 9 and the support for the local forces associated with the unsettled subsidence of the levee 5 due to liquefaction during an earthquake and the collision of drifting objects caused by the tsunami flow are retained by the gap. The wall precast plates 11 can move with each other.

  Therefore, the local force generated in the precast retaining wall 1 can be dispersed and destruction can be prevented.

  Furthermore, according to the first embodiment, the sheath pipe 35 is provided inside the retaining wall precast plate 11 so as to be substantially parallel to the end face, and a plurality of wires 37 provided in the sheath pipe 35 are provided. The retaining wall precast plate 11 is connected.

  Therefore, since the plurality of retaining wall precast plates 11 share the impact force with respect to the tsunami 40, the durability of the precast retaining wall 1 can be improved.

Further, according to the first embodiment, the shear keys 38 a and 38 b are provided on the bottom surface of the basic precast plate 9 of the precast retaining wall 1, and the shear keys 38 a and 38 b resist the impact force of the tsunami 40. To do.
Therefore, the movement of the basic precast plate 9 due to the tsunami can be prevented.

  Furthermore, according to the first embodiment, the precast retaining wall 1 does not have an operating portion unlike the storage-type retaining wall, so that the embankment 5 can be raised without fail, and can reliably be used in the event of an earthquake or tsunami. Act on.

Next, a second embodiment will be described.
FIG. 10 is a cross-sectional view showing a precast retaining wall 1a according to the second embodiment.
In addition, in 2nd Embodiment, the same number is attached | subjected to the element which performs the same function as the precast retaining wall 1 which concerns on 1st Embodiment, and description is abbreviate | omitted.

  Unlike the precast retaining wall 1 according to the first embodiment, the precast retaining wall 1a in the second embodiment is provided on the water-permeable revetment 60, and the basic precast plate 9 is attached to the revetment 60 by anchors 41a and 41b. It is fixed.

  Further, a scour preventing mat 43 is provided around the front surface of the basic precast plate 9.

  As shown in FIG. 10, the precast retaining wall 1 a is provided on a water-permeable revetment 60 such as rubble or banking, and anchors 41 a and 41 b are provided in the through holes 21 b and 21 d of the foundation precast plate 9.

  The anchors 41 a and 41 b are inserted into the revetment 60, and the foundation precast plate 9 is fixed to the revetment 60.

  An anchor (not shown) is also provided in the through holes 21a and 21c. The anchor (not shown) penetrates into the revetment 60 and fixes the foundation precast plate 9 to the revetment 60.

  By providing the anchor in this way, the pulling resistance due to the tumbling moment due to the tsunami increases, and the precast retaining wall 1 can be further prevented from falling and moving.

The precast retaining wall 1 a is provided with a scour preventing mat 43 around the front surface of the basic precast plate 9.
The scour prevention mat 43 is a member that prevents scouring of the revetment 60 due to a tsunami, and an asphalt mat or the like is used.

  When the revetment 60 is constructed of a water-permeable material, the tsunami acts on the front surface of the precast retaining wall 1 during the tsunami.

  And when the water level rises, the flow along the precast retaining wall 1 or the return flow increases the flow velocity of the front surface of the precast retaining wall 1, and scouring may occur abruptly.

However, by providing the scouring prevention mat 43, it is possible to prevent scouring of the front surface of the precast retaining wall 1, and to prevent the precast retaining wall 1 from falling or moving due to scouring.
In addition, the laying range of the scour preventing mat 43 is a range of about 0.5D to 1D, where D is the length of the basic precast plate 9.

  As described above, according to the second embodiment, the precast retaining wall 1 a has the basic precast plate 9 and the retaining wall precast plate 11.

  Accordingly, the same effects as those of the first embodiment are obtained.

  According to the second embodiment, the precast retaining wall 1a is provided with anchors in the through holes 21a, 21b, 21c, and 21d of the basic precast plate 9.

  Therefore, the pull-out resistance due to the tumbling moment due to the tsunami increases, and the precast retaining wall 1 can be further prevented from falling and moving.

Furthermore, according to the second embodiment, the scour preventing mat 43 is provided around the front surface of the basic precast plate 9.
Therefore, scouring around the front surface of the precast retaining wall 1 can be prevented, and the precast retaining wall 1 can be further prevented from falling or moving due to scouring.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

The perspective view which shows the embankment 5 in which the precast retaining wall 1 was provided The figure which shows the minimum structural unit of the precast retaining wall 1 A-A cross-sectional view of FIG. The figure which shows the basic precast version 9 of the precast retaining wall 1 The figure which shows the retaining wall precast version 11 of the precast retaining wall 1 The figure which shows the recording block 13 of the precast retaining wall 1 Enlarged sectional view showing the connecting portion between the retaining wall precast plates 11 Figure showing the vicinity of embankment 5 at the time of the tsunami Longitudinal sectional view of the precast retaining wall 1 of FIG. Sectional view showing precast retaining wall 1a

Explanation of symbols

1 ………… Precast retaining wall 3 ………… Sand beach 5 ………… Elevation 7 ………… Sea 9 ………… Basic precast version 11 ………… Retaining wall precast version 13 ………… Reception block 15… ... Main body 17 ......... Groove portion 19a ...... Protrusions 21a ... Through hole 25 ......... Main body 27 ......... Protrusions 29a ... Protrusions 31a ... Through holes 33a ... Evacuation step 35 ... …… Sheath Pipe 37 ......... Wire 39 ......... Gap 40 ......... Tsunami 41 ......... Filler 38a ... Shear key 41a ... Anchor 43 ......... Scouring prevention mat 51 ......... Drifting material

Claims (10)

A foundation precast plate laid on a revetment or embankment and having a first engaging portion on the upper surface;
A retaining wall precast plate having a second engagement portion that engages with the first engagement portion on an end surface;
A precast retaining wall characterized by having. The material constituting the foundation precast plate and / or the retaining wall precast plate is concrete having a compressive strength of 100 to 250 N / mm ² and a bending tensile strength of 10 to 40 N / m ^2. Precast retaining wall as described.   The precast retaining wall according to claim 1, wherein the foundation precast plate has a first connection structure connected to another foundation precast plate.   2. The precast retaining wall according to claim 1, wherein the retaining wall precast plate has a second connection structure coupled to another retaining wall precast plate. 3.   When the retaining wall precast plate is connected to another basic precast plate, a gap is provided between the first connection structures, and the gap is filled with a water-stopping filler. 5. Precast retaining wall according to claim 4 A sheath tube provided inside the retaining wall precast plate,
The precast retaining wall according to claim 3, further comprising a wire provided in the sheath tube and connecting a plurality of the precast plates.   The precast retaining wall according to claim 1, wherein a protrusion is provided on a bottom surface of the foundation precast plate.   The precast retaining wall according to claim 1, further comprising a scour prevention mat provided around the foundation precast plate. Connecting and laying a plurality of foundation precast plates on a revetment or embankment (a);
Engaging the second engaging portion provided on the end surface of the retaining wall precast plate with the first engaging portion provided on the basic precast plate;
Connecting the side surfaces of the retaining wall precast plate (c);
A method for constructing a precast retaining wall.   The step (c) is a step of providing a sheath pipe inside the retaining wall precast plate and connecting adjacent retaining wall precast plates through a wire in the sheath tube. How to build a precast retaining wall.

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