JP2002194756A - Obtuse l-shaped concrete retaining wall block, obtuse l-shaped concrete retaining wall unit, and method for constructing concrete retaining wall using the unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an obtuse L-shaped block which facilitates setting thereof at a predetermined location on a foundation portion, and allows its vertical surface to be safely adjusted by simple work, and to provide a retaining wall unit, and a method for constructing a concrete retaining wall using the retaining wall unit. SOLUTION: The retaining wall unit is formed of the obtuse L-shaped block set on the foundation portion, and a position defining means for defining the obtuse L-shaped block to a predetermined location. The obtuse L-shaped block is formed of a bottom plate extending from a lower edge of a vertical wall at an opening angle of about 105 deg., a horizontal portion forming a horizontal plane at a location immediately below the vertical wall, an engaging recess formed in the horizontal portion, and a plurality of mortar injection holes piercing the bottom plate at locations in the vicinity of the vertical wall. The position defining member has an engaging projection for engaging with the engaging recess of the obtuse L-shaped block when fixed to the foundation portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an installed obtuse angle L-shaped concrete retaining wall block used for forming a retaining wall for land preparation and the like, and a base of the obtuse angle L-type concrete retaining wall block. The present invention relates to an obtuse angle L-shaped concrete retaining wall unit including a position defining member for accurately installing the unit at a predetermined position on a part. The present invention also relates to a method for constructing a concrete retaining wall using the above obtuse angle L-shaped concrete retaining wall unit.

[0002]

2. Description of the Related Art L-type concrete retaining wall blocks are used for the purpose of constructing a retaining wall vertically on a foundation.
A conventional L-shaped concrete retaining wall block is composed of a bottom plate extending substantially perpendicularly to a vertically extending straight wall portion,
It is installed while supported on a horizontal foundation.

However, in such a right angle L-shaped concrete retaining wall block that opens at an angle of about 90 °, a sufficient sliding resistance is obtained, and the specified value for the backfill depth of the L-shaped concrete retaining wall block is cleared. Therefore, it is necessary to backfill the front surface of the retaining wall block to a specified depth or to increase the width of the bottom plate to increase the safety against sliding. For this reason, it is difficult to reduce the size and weight of the product, and when transporting heavy retaining wall blocks, it is also necessary to install it at a predetermined position during construction and align it with the adjacent retaining wall block and height. It is very difficult to perform such operations. In addition, prior to installing the retaining wall block,
The mortar for fixing the base portion and the bottom plate is provided on the base portion with a liner plate disposed near the end face on the extended end side of the bottom plate and a position corresponding to the end face on the straight wall portion, and on both side surfaces of the bottom plate. It is necessary to lay beforehand in the area surrounded by the wooden base plate provided at each corresponding position, and if adjustment such as face matching is significant, change to a liner plate of a suitable size. Drawbacks, such as the need for re-padding or additional paving of mortar, and the use of non-shrink mortar for mortar, resulting in increased installation costs and the consumption of large amounts of resources and materials. There is also.

In the right angle L-type concrete retaining wall block, it is necessary to adjust the height of the straight wall portion, and when the base portion needs to be rehabilitated, the height of the entire base portion is increased. The disadvantage is that adjustments have to be made. In order to eliminate such a drawback, an obtuse angle, for example, approximately 105
An obtuse angle L-shaped concrete retaining wall block provided with a bottom plate having an angle of .degree. Has been proposed (for example, Utility Model Registration No. 3).
No. 022072, Japanese Utility Model Publication No. 7-14435, etc.).

[0005]

However, in such a conventional obtuse angle L-shaped concrete retaining wall block, although the size and the weight have been reduced while the safety against sliding has been enhanced, the installation and construction have been carried out. In this case, in addition to the surface matching between adjacent obtuse angle L-shaped concrete retaining wall blocks and the height adjustment, there still remains a problem in adjusting the vertical installation angle of the obtuse angle L-type concrete retaining wall block. That is, the obtuse angle L-shaped concrete retaining wall blocks are aligned with the outer wall surface of the straight wall portion, which is the surface opposite to the inner wall surface side of the straight wall portion on the side where the bottom of the obtuse angle L-shaped concrete retaining wall block is provided. When adjusting the clearance between the retaining walls in the length direction and adjusting the height, the installation work must be performed while raising and lowering the suspension several times in a suspended state with a crane. It had a cause that increased the construction cost. Further, although it is not necessary to use a non-shrink mortar, prior to installing the obtuse angle L-shaped concrete retaining wall block, it was necessary to lay mortar for fixing the foundation and the base.

An object of the present invention is to eliminate the above-mentioned drawbacks in the conventional obtuse angle L-shaped concrete retaining wall block,
An object of the present invention is to provide an obtuse angle L-type concrete retaining wall block and an obtuse angle L-type concrete retaining wall unit that are small and light in weight, can be easily installed, and save resources and materials. Still another object of the present invention is to provide a construction method of an obtuse angle L-type concrete retaining wall constructed using the above obtuse angle L-type concrete retaining wall unit.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 provides an obtuse angle L-type concrete retaining wall block (or an oblique-angle concrete retaining block installed on a foundation provided at a retaining wall installation location). An obtuse angle L-shaped block), which is provided with a straight wall portion that is disposed vertically on the base portion, and a bottom plate that extends at an obtuse angle from a lower end of the straight wall portion, and is directly below the straight wall portion. A horizontal portion that forms a substantially horizontal plane in a portion located at a position, an engagement concave portion that is formed in the horizontal portion and engages with an engagement convex portion provided on the base portion, and a position close to the straight wall portion. And a plurality of mortar filling holes penetrating the bottom plate.

According to a second aspect of the present invention, in the obtuse angle L-shaped block according to the first aspect, an angle formed by the bottom plate with respect to the straight wall portion is 105 ° ± 10 °.

The invention described in claim 3 is the first or second invention.
In the obtuse angle L-shaped block described in 1 above, a bolt insertion hole is formed at the tip of the bottom plate, and an embedding nut is embedded in the bolt insertion hole so as to coincide with the axis of the bolt insertion hole. By rotating an angle adjusting bolt inserted through the nut, the angle of the straight wall portion can be adjusted when the obtuse angle L-shaped concrete retaining wall block is installed. Features.

According to a fourth aspect of the present invention, there is provided an obtuse angle L-shaped concrete retaining wall unit (or a retaining wall unit) including the obtuse angled L-shaped block according to any one of the first to third aspects. And a position defining member fixed to the base portion and defining an installation position of the obtuse angle L-shaped block, wherein the position defining member is fixed to the base portion and the engaging recess of the obtuse angle L-shaped block is provided. Characterized in that it has an engaging projection that engages with.

According to a fifth aspect of the present invention, in the retaining wall unit according to the fourth aspect, the position defining member is a member having an L-shaped cross section, and an upright portion constitutes the engaging projection. It is characterized by doing.

According to a sixth aspect of the present invention, in the retaining wall unit according to the fourth aspect, the positioning member has a main body and a plurality of frusto-conical projections provided on the surface thereof. And a projection.

[0013] Further, in order to achieve the above object, a seventh aspect of the present invention is provided.
The present invention provides a concrete retaining wall construction method for constructing an obtuse angle L-shaped concrete retaining wall using the retaining wall unit according to any one of claims 4 to 6, wherein the foundation is formed at a retaining wall installation location. Position setting member setting step of setting the position specifying member at a predetermined position of the horizontal surface portion of the portion, and setting the obtuse angle L-shaped block in a state where the engaging concave portion and the engaging convex portion of the position specifying member are engaged. It is characterized by comprising an engaging installation step and a mortar filling step of filling the mortar into the space between the base portion and the bottom of the obtuse angle L-shaped block through the mortar filling hole.

According to an eighth aspect of the present invention, in the method for constructing a concrete retaining wall according to the seventh aspect, the engaging and setting step includes adjusting the angle by passing through the bolt insertion hole and the embedded nut of the bottom plate. And turning the bolt to adjust the angle of the straight wall portion of the obtuse L-shaped block that forms the outer wall surface of the concrete retaining wall.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An obtuse angle L-type concrete retaining wall block (obtuse angle L-type block), an obtuse angle L-type concrete retaining wall unit (retaining wall unit) and a concrete retaining wall constructed using the retaining wall unit according to the present invention. Hereinafter, an embodiment of the construction method will be described in more detail with reference to the drawings.

FIG. 1 shows an obtuse angle L-shaped block according to an embodiment of the present invention, and FIG. 2 shows a position defining member used as a retaining wall unit in combination with the obtuse angle L-shaped block. 5 shows a state where the obtuse angle L-shaped block and the position defining member are installed at predetermined positions on the foundation.

First, the obtuse angle L-shaped block 1 shown in FIG. 1 is disposed vertically at a predetermined installation location where a retaining wall is to be formed on a foundation B made of concrete at a correct position. A straight wall portion 2 and a bottom plate 3 extending at an obtuse angle from the lower end of the straight wall portion 2. Preferably, an appropriate number (two in this example) is provided between the straight wall portion 2 and the bottom plate 3. Are provided.

The dimensions of the obtuse angle L-shaped block 1 having such a structure are appropriately selected according to various conditions of the construction site. For example, the height of the horizontal portion 2 is about 1.5.
m, the length is about 2 m, and an obtuse angle L-shaped block 1 having the same structure is continuously installed in the length direction to form a long concrete retaining wall.

The opening angle at which the base 3 extends at an obtuse angle with respect to the straight wall portion 2 is approximately 105 °, specifically 105 °.
An angle range of ° ± 10 ° is preferable, and 105 ° ± 10 °
A range of 5 ° is recommended. When the angle is less than 95 °, the effect of preventing the activity as the obtuse angle L-shaped block is almost lost, so that the base 3 needs to be enlarged, and when the base B and the base 3 are fixed via mortars, In order to prevent the generation of a gap between the bottom of the base 3 and the mortar, it is necessary to use a non-shrinkable mortar. on the other hand,
If the angle exceeds 115 °, there is a problem in the strength of the obtuse angle L-shaped block itself. Therefore, significant reinforcement such as reinforcement of reinforcing bars is required, and measures for preventing falling and tilting of the L-shaped concrete retaining wall should be considered. It will be.

Further, on the bottom surface of the obtuse angle L-shaped block 1, a horizontal portion 5 forming a substantially horizontal plane is formed at a portion located directly below the straight wall portion 2. Further, the horizontal portion 5 has an engagement concave portion having a predetermined shape for engaging with an engagement convex portion of a position defining member 20 (illustrated in detail later), an example of which is shown in FIG. 7 are formed. FIG.
In this embodiment shown in FIG. 3 to FIG. 3, the engaging concave portion 7 is formed in a shape of a substantially L-shaped groove extending in the longitudinal direction of the obtuse angle L-shaped block 1, but will be described later. In addition, any shape may be used as long as the shape appropriately engages with the engaging projection provided on the base portion B.

On the other hand, the bottom plate 3 has a plurality of mortar filling holes 8 penetrating the bottom plate 3 at a position close to the straight wall portion 2.
However, a bolt insertion hole 9 is provided at an end farthest from the straight wall portion 2. In this example, as shown in FIG. 3, an embedding nut 10 is embedded in the bottom plate 3 so that the axes of the bolt insertion holes 9 coincide with each other, and penetrates the bolt insertion hole 9 and the embedding nut 10. When the bolt 11 for angle adjustment is inserted, the tip of the bolt 11 protrudes downward from the lower surface of the bottom plate 3 and comes into contact with the surface of the base portion B.

A position defining member 20 as shown in FIG. 2 is fixed to the base portion B. This position defining member 20
A horizontal portion 21 and a vertical portion 22 standing substantially perpendicularly from one edge of the horizontal portion 21 are formed, and the anchor bolt 23 is driven into the base portion B through a plurality of holes provided in the horizontal portion 21, thereby forming the base portion. The portion B is fixed at a predetermined position. The position defining member 20 can also embed and fix the horizontal portion 21 from the surface of the base portion B in a state where the concrete of the base portion B is semi-solidified without using the anchor bolt 23.

The position defining member 20 may be, for example, a steel L-shaped angle member extending over the entire length of the area where the concrete retaining wall is to be formed, but more precisely defines the position of the obtuse angle L-shaped block 1. 10cm to do
It is preferable to provide steel members having a length and a predetermined thickness at appropriate intervals so that approximately two obtuse angle L-shaped blocks 1 are arranged.

As shown in FIG. 3, the position defining member 20 is formed on the horizontal portion 5 of the obtuse angle L-shaped block 1 with the obtuse angle L-shaped block 1 installed at a predetermined position on the base portion B. The engagement convex portion 6 composed of the vertical portion 22 and the horizontal portion 21 rushes into and engages with the engagement concave portion 7, so that the obtuse angle L-shaped block 1 has a front-rear direction (a thickness direction of the straight wall portion 2), The thickness direction of the straight wall portion 2 corresponding to the direction in which the outer wall surface of the straight wall portion 2 that forms the outer wall surface of the concrete retaining wall is perpendicular to the outer wall surface, and the length direction of the obtuse angle L-shaped block 1 (concrete retaining portion) The lengthwise direction of the wall), that is, the movement of the straight wall portion 2 in the front and back directions on the drawing surface on the outer wall surface is prevented, and the reliability of the installation work of the obtuse angle L-shaped block 1 is improved,
In addition, the installation period can be shortened to facilitate the installation. In the example shown in FIGS. 2 and 3, the entirety of the position defining member 20 constitutes the engagement convex portion 6. However, when the horizontal portion 21 is embedded in the base portion B, the position defining member 20 is formed. The vertical portion 22 which is a rising portion of the straight line forms the engaging convex portion 6, and as the engaging concave portion 7 of the obtuse angle L-shaped block 1, a straight line extending in the longitudinal direction of the obtuse angle L-type block 1 with a predetermined width and depth. It properly engages with the engaging concave portion 7 formed as a simple groove (not shown).

The obtuse angle L-shaped block 1 constructed as described above
As an operation of constructing an obtuse angle L-shaped concrete retaining wall using the retaining wall unit including the position defining member 20, the base portion B is provided at a retaining wall installation location prior to the installation work of the obtuse angle L-shaped block 1. (Foundation part construction work process). The base part B has a shape suitable for the horizontal part 5 of the obtuse angle L-shaped block 1 to be installed, that is, a substantially horizontal base part B having a width suitable for the length in the thickness direction of the straight wall part 2 in the horizontal part 5. With respect to the straight wall portion 2 in a state where the oblique angle L-shaped block 1 to be installed is installed at a normal position and an inclined surface which is inclined at a predetermined angle from the horizontal surface portion and extends downward by a predetermined length. And an inclined surface portion having an inclined surface extending at an angle exceeding the opening angle formed by the bottom plate 3 in the direction in which the bottom plate 3 extends in the direction in which the bottom plate 3 extends. . Here, the inclination angle of the inclined surface portion of the base portion B, that is, the inclination angle from the vertical surface serving as the outer wall surface of the concrete retaining wall to the inclined surface portion surface of the foundation portion B is determined by the opening angle of the obtuse angle L-shaped block 1 installed. Although an angle larger by about 5 ° to 10 ° with respect to the angle is preferable,
It can be determined appropriately according to the retaining wall installation location, construction conditions, and the like.

Following such a foundation part installation work process,
A position defining member installation step of fixingly installing the position defining member 20 at a predetermined position in the horizontal plane portion of the base portion B is performed.
In the position determining member installation step of the present embodiment, as the fixing position of the position determining member 20, as shown in FIG. 2, the extending end surface 24 on the extending end side of the horizontal portion 21 extending substantially perpendicularly from the vertical portion 22 is used. , Is fixedly installed on the horizontal surface along the boundary between the horizontal surface and the inclined surface of the base portion B.
However, it is important that it is fixedly installed on the horizontal surface of the base part B along the plane parallel to the retaining wall of the concrete retaining wall to be constructed. When the anchor bolt 23 is driven into the base portion B by penetrating the horizontal portion 21 of the position defining member 20, the position defining member setting step is performed after the concrete forming the base portion B is solidified in the base part setting work step. However, when the position defining member 20 is fixed without using the anchor bolt 23, the horizontal portion 21 of the position defining member 20 is embedded and fixed in a state where the concrete of the base portion B is semi-solidified.

Next, the operation proceeds to an engagement installation step of installing the obtuse angle L-shaped block 1 in a state where the engagement concave portion 7 and the engagement convex portion 6 of the position defining member 20 are engaged. In this engagement installation step, the obtuse angle L-shaped block 1 is gradually moved by using a crane or the like so that the engagement concave portion 7 of the obtuse angle L-shaped block 1 is engaged with the engagement projection 6 fixed to the base portion B. After lowering and engaging, the outer wall surface of the concrete retaining wall is rotated by rotating a bolt 11 for angle adjustment that has been inserted through the bolt insertion hole 9 and the embedded nut 10 of the bottom plate 3 with a wrench or the like. Straight wall 2 of obtuse angle L-shaped block 1 to be formed
And a wall angle adjusting step of adjusting the angle of the wall.

In this wall angle adjustment step, the difficult work that was conventionally performed while hanging with a crane in the installation work of the obtuse angle L-shaped block in the related art, but in the method according to the present invention, the bolt 11 is simply turned forward or backward. With a simple and safe operation, the height of the tip of the bottom plate 3 and the angle of the straight wall portion 2 can be easily and accurately adjusted. Also, by providing the position defining member installation step before the engagement installation step, the conventional obtuse angle L-shaped concrete retaining wall block installation work
The extremely difficult and time-consuming work such as surface alignment on the outer wall surface of the straight wall portion, gap adjustment in the length direction of the retaining wall where the obtuse angle L-shaped blocks are arranged, and height adjustment are difficult. It is possible to complete the operation in a short time only by a simple engagement work in the engagement installation step including the adjustment step. In addition, the bolt 11 used in the wall angle adjustment step is inserted into the bolt insertion hole 9 of the bottom plate 3 at the end of the wall angle adjustment.
After fitting a liner plate that fits the gap between the bottom surface of the bottom plate 3 and the surface of the inclined surface portion of the base portion B at a position on the tip side of the bottom plate 3, it can be removed and reused. is there.

After the completion of the engagement installation step including the wall angle adjustment step, the base portion B is passed through the mortar filling hole 8 of the bottom plate 3.
A mortar filling step of filling the mortar into the space between the inclined surface of the bottom surface and the bottom plate 3 is performed. In this mortar filling step, concrete or mortar is filled by using a mortar filling hole 8 using the inclination of the inclined surface of the base portion B.
In order to fill by filling from the base, the obtuse angle L-shaped block and the base portion B are formed without forming a gap on the lower surface of the bottom plate 3 without using a non-compressed mortar or the like required in the case of construction using a conventional L-shaped block. Are more firmly integrated. Further, by this mortar filling step, it is possible to construct a highly safe concrete retaining wall excellent in slip resistance by simpler operation than in the construction using a conventional obtuse angle L-shaped block.

FIG. 4 shows a position defining member 30 according to another embodiment of the present invention. In this example, a plurality of (four in this example) engaging projections 32 are provided on one surface of a substantially rectangular plate-shaped main body 31 at appropriate intervals.
Is provided. The engagement projection 32 of this example is
It is constituted by a frusto-conical steel lock pin having a large diameter at the lower end. Further, the engaging recess 7 provided at a position corresponding to the horizontal portion 5 of the obtuse angle L-shaped block 1 has the same shape.

FIGS. 5 and 6 show the engagement state with the obtuse angle L-shaped block 1 when the position defining member 30 shown in FIG. 4 is used.
Shown in In this example, the position defining member 30 has a central portion in the length direction fixed to the base portion B at an intermediate position between two adjacent obtuse angle L-shaped blocks 1 and two engagement protrusions located on one side. The part 32 is connected to one obtuse angle L-shaped block 1
Engagement recesses 7 and two engagement projections 32 located on opposite sides are formed by two engagement recesses 7 of the other obtuse angle L-shaped block 1.
Respectively. In addition, the shape of this engagement convex part 32,
The number and arrangement can be arbitrarily changed according to various conditions.

The shape of the engaging concave portion 7 may be the same as the shape of the corresponding engaging convex portion 32. However, when the engaging convex portion 32 has a frusto-conical shape as shown in FIG. As shown in FIG. 6, it is preferable that the engaging protrusion 32 has a frusto-conical shape that is deeper than the height thereof and has a large inclination angle. When the engagement concave portion 7 that satisfies such conditions is provided, in the engagement installation step of lowering the obtuse angle L-shaped block 1 to a predetermined position on the base portion B using a crane, The operation of engaging the engaging concave portion 7 of the obtuse angle L-shaped block 1 with the engaging convex portion 32 of the position defining member 30 fixed to B is further facilitated, and the obtuse angle L
In the process of lowering the mold block 1 to a predetermined position, the mold block 1 is guided by the slope of the engaging projection 32 and guided to the correct position, so that the obtuse angle L-shaped block 1 is positioned and is adjacent to the retaining wall in the longitudinal direction. The work of making the distance between the side walls of the obtuse angle L-shaped block 1 constant can be performed easily and accurately.

[0033]

According to the present invention as described above,
By providing the horizontal portion having a predetermined length immediately below the straight wall portion, foundation construction that does not require the height adjustment of the obtuse angle L-shaped concrete retaining wall block during installation work can be easily performed. Also, when installing the obtuse angle L-type concrete retaining wall block, after adjusting with the bolts for angle adjustment, the height of the tip of the bottom plate can be adjusted using the liner plate and the vertical of the straight wall can be brought out, so installation The adjustment work for the frontal alignment of the obtuse angle L-shaped block at the time of construction becomes unnecessary.

Furthermore, ordinary concrete can be poured from the mortar filling hole provided in the bottom plate by utilizing the inclination of the surface of the base portion, and the space between the base portion and the bottom plate can be filled with concrete. The effect that the concrete retaining wall block can be easily fixed can also be obtained. In addition, the foundation embedded in the ground at the site and the obtuse angle L-shaped block are more firmly integrated with mortar, making it easier to install a highly safe concrete retaining wall with excellent slip resistance, reducing construction costs. A remarkable and unique effect is obtained in that the time can be significantly reduced and the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an obtuse angle L-shaped concrete retaining wall block according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a position defining member used with the obtuse angle L-shaped concrete retaining wall block shown in FIG.

3 is a longitudinal sectional view showing a state in which the obtuse angle L-shaped concrete retaining wall block shown in FIG. 1 is installed on a foundation using the position defining member shown in FIG. 2;

FIG. 4 is a perspective view showing a position defining member according to another embodiment of the present invention.

5 is a partial longitudinal sectional view showing the position defining member shown in FIG. 4 and two concrete obtuse angle L-shaped blocks installed at predetermined positions by the member.

FIG. 6 is an enlarged vertical sectional view of a part of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Obtuse angle L-shaped block 2 Straight wall part 3 Bottom board 4 Reinforcement rib 5 Horizontal part 6 Engagement convex part 7 Engagement concave part 8 Mortar filling hole 9 Bolt insertion hole 10 Embedded nut 11 Bolt 20, 30 Positioning member 21 Horizontal part 22 Vertical part 23 Anchor bolt 24 Extended end face 31 Main body 32 Engagement convex part

Claims (8)

[Claims] 1. An obtuse angle L-shaped concrete retaining wall block installed on a foundation provided at a retaining wall installation location, wherein the straight wall is vertically disposed while being installed on the foundation. A bottom plate extending at an obtuse angle from a lower end of the straight wall portion, a horizontal portion forming a substantially horizontal plane in a portion located immediately below the straight wall portion, and a horizontal portion formed on the horizontal portion and provided on the base portion. An obtuse angle L-shaped concrete retaining wall block, comprising: an engaging concave portion engaging with an engaging convex portion; and a plurality of mortar filling holes penetrating the bottom plate at a position close to the straight wall portion. 2. The obtuse angle L-shaped concrete retaining wall block according to claim 1, wherein an angle formed by the bottom plate with respect to the straight wall portion is 105 ° ± 10 °. 3. A bolt insertion hole is formed at a tip portion of the bottom plate, and an embedding nut is embedded in the bolt insertion hole so as to coincide with an axis of the bolt insertion hole. By rotating an angle adjusting bolt that is inserted therethrough, the angle of the straight wall portion can be adjusted when the obtuse angle L-shaped concrete retaining wall block is installed. The obtuse angle L-shaped concrete retaining wall block according to claim 1 or 2, wherein: 4. An obtuse angle L-shaped concrete retaining wall unit comprising the obtuse angle L-type concrete retaining wall block according to claim 1, wherein the obtuse angle L-type concrete retaining wall is fixed to the base portion. A position defining member for defining an installation position of the block, wherein the position defining member has an engaging convex portion that engages with the engaging concave portion of the obtuse angle L-shaped concrete retaining wall block while being fixed to the foundation. An obtuse angle L-shaped concrete retaining wall unit, characterized in that: 5. The obtuse angle L-shape according to claim 4, wherein the position defining member is a member having an L-shaped cross section, and an upright portion constitutes the engaging projection. Concrete retaining wall unit. 6. The positioning member according to claim 4, wherein the position defining member includes a main body, and an engagement projection having a plurality of frustoconical projections provided on a surface of the main body. Obtuse angle L-shaped concrete retaining wall unit. 7. A construction method for constructing an obtuse angle L-shaped concrete retaining wall using the obtuse angle L-type concrete retaining wall unit according to any one of claims 4 to 6, wherein the method is formed at a retaining wall installation location. A position defining member installation step of installing the position defining member at a predetermined position on a horizontal surface portion of the base portion; and forming the obtuse angle L-shaped concrete retaining wall block with its engaging concave portion and the engaging convex portion of the position defining member. An engaging installation step of installing in an engaged state, and a mortar filling step of filling mortar in a space between the base portion and the bottom of the obtuse angle L-shaped concrete retaining wall block through the mortar filling hole. Construction method of concrete retaining wall characterized by having. 8. The straight wall forming an outer wall surface of a concrete retaining wall by rotating an angle adjusting bolt inserted through a bolt insertion hole and an embedding nut of the bottom plate. The method for constructing a concrete retaining wall according to claim 7, further comprising a wall angle adjusting step of adjusting an angle of the portion.