JP7197841B2 - Precast foundation block - Google Patents

Description

TECHNICAL FIELD The present invention relates to a precast foundation block having wall panels installed in multiple stages above and serving as the foundation of a retaining wall.

Conventionally, as this type of precast foundation block, there is a foundation block for constructing a retaining wall disclosed in Patent Document 1, for example.

This foundation block has a step formed on a predetermined reference line aa for arranging the building blocks on the inclined surface of the foundation block body, and has a horizontal flat surface with this reference line aa as a starting point. part is formed. The short width h of the flat portion is set to h=R−(R cos θ), where R is the construction radius of the retaining wall to be constructed. A pedestal extends horizontally from the lower portion of the inclined surface of the base block body and is integrally formed. The building blocks are laid following the imaginary arc-shaped block arrangement line bb within the width h of the flat part. easily arranged in an arc. That is, the building blocks to be laid on both longitudinal ends of the foundation blocks are aligned with the bottom edge of the flat portion, and the building blocks to be laid in the longitudinal center of the foundation block are aligned with the top edge of the flat portion. If the building blocks located in the middle are laid in an arc shape, they will naturally be arranged in the desired curved shape.

Registered Utility Model No. 3005147

With the conventional retaining wall construction foundation blocks disclosed in Patent Document 1, the building blocks can be stacked by easily determining the relative confrontation between the foundation blocks and the building blocks to be stacked above them as described above. However, building blocks are stacked above the foundation blocks, and are generally rectangular parallelepiped shaped like cones that widen toward the panel portion installed on the slope side of the retaining wall. For this reason, conventional foundation blocks for constructing retaining walls are installed above wall panels of a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete placed behind the panels and move. It cannot be the basis of a retaining wall to be formed. In addition, even if it is easy to determine the relative position of the building blocks to be stacked on the base block, the number of building blocks to be stacked per unit area increases, so it is not easy to stack many building blocks in the determined position. , takes a lot of time and manpower to work. As a result, the construction cost of the retaining wall could not be suppressed.

According to the present invention, a wall panel having a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete can be easily installed upwards with good workability and used as the foundation of the retaining wall. To provide a precast foundation block capable of suppressing construction cost of a wall.

For this reason, the present invention
In a precast foundation block that serves as the foundation of a retaining wall, a wall panel of a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete that is poured behind the panel and moves, is installed above.
It consists of an upright portion on which the wall panel is installed and a supporting leg portion that extends in a direction intersecting the upright portion and supports the upright portion, and a fall prevention member is fixed to prevent the upper wall panel from overturning. A fixing member is provided at a predetermined position of the supporting leg to hold the first connecting member, which is attached to the wall panel stacked on the upper end of the upright leg and contacts the downward projecting portion of the first connecting member projecting downward from the wall panel. The wall surface to which the second connecting member is attached and pushed, and the portion protruding upward from the upper end of the upright leg abuts and pushes the back surface of the wall panel stacked on the upper end of the upright leg is attached to the head of the upright leg characterized by being provided on the support leg side of the

According to this configuration, by providing the fixing member to the support leg, it is possible to provide the overturn prevention member between the fixing member and the back surface of the wall panel installed above the foundation block. Since the wall panel is of a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete, it is light in weight and easy to handle even if it is larger than conventional building blocks. The number used per area can be greatly reduced. Installation of a small number of such wall panels above the foundation block using anti-tipping members is a simple task that does not require time and manpower. For this reason, a wall panel having a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete can be easily installed upwards with good workability and used as the foundation of the retaining wall. It is possible to provide a precast base block that can reduce the construction cost of. In addition, since the fixing member is provided at a predetermined position on the support leg, the installation position of the fixing member does not have to be calculated each time in consideration of the relative position between the wall panel and the foundation block installed above. Typically, the wall panels can be installed above the foundation blocks.

Further, the present invention is characterized in that the fixing member is detachably provided on the support leg.

According to this configuration, since the fixing member can be attached to the support leg, the base block can be molded without the fixing member, which facilitates the manufacture of the base block. In addition, the handling of the foundation blocks during storage, transportation, etc. becomes easier.

Further, the present invention is characterized in that the wall panel is engaged with the upright portion so that the lower end is positioned at the upper end of the upright portion or is independently connected to the upright portion.

According to this configuration, when providing the overturning prevention member between the panel rear surface of the wall panel and the fixing member, the lower end of the wall panel is positioned at the upper end of the standing leg of the foundation block, or the wall surface is positioned at the upper end of the standing leg. The panel can stand on its own. Therefore, when providing the overturn prevention member, it is easy to provide the support material for holding the wall panel above the foundation block by aligning the lower end of the wall panel with the upper end of the standing leg without shifting. workability of construction work is improved. Alternatively, by allowing the wall panel to stand on its own at the upper end of the standing leg, the work of providing support material becomes unnecessary, the construction process of the retaining wall is simplified, and the construction cost of the retaining wall can be reduced.

In addition, the present invention is characterized in that the fixing member is provided on the support leg portion behind the standing leg portion and away from the position where the overturn prevention member is attached to the upper portion of the wall panel installed on the lowest stage.

If the fixing member is provided on the support leg at a position closer to the standing leg than the top of the wall panel installed on the lowest level where the anti-toppling member is attached, the wall panel can be prevented from tipping over to the front of the wall surface. , the overturning to the rear side of the wall surface cannot be effectively prevented. However, according to this configuration, it is possible to effectively prevent both the overturning of the wall panel toward the front side of the wall surface and the overturning toward the rear side of the wall surface.

Further, the present invention is characterized in that the supporting leg extends in a direction intersecting the standing leg from a position spaced apart from the upper end of the standing leg by a predetermined distance.

In the conventional foundation block disclosed in Patent Document 1, the foundation portion of the retaining wall is constructed by placing the foundation block and then pouring concrete into the opening of the foundation block for curing. After that, the lowermost building blocks are placed on the foundation blocks, and backfill concrete is placed behind them for curing to build up the lowermost building blocks. However, according to this configuration, since the support leg extends in a direction intersecting the standing leg from a position spaced from the upper end of the standing leg by a predetermined distance, the supporting legs are installed behind and at the bottom of the standing leg with a predetermined space. A space is formed by connecting to the back of the wall panel. Therefore, by placing back-filling concrete in this space, back-filling concrete is simultaneously formed behind the foundation block and behind the wall panel installed at the bottom level, and is installed at the base part and the bottom level of the retaining wall. The construction part of the wall panel to be constructed is constructed in one time of pouring concrete and one time of curing thereof. Therefore, it is possible to reduce the construction process for constructing the retaining wall.

In conventional foundation blocks, a boundary surface is structurally formed between the upper surface of the foundation block and the backfill concrete that is cast behind the building blocks on the lowest level. Earth pressure from the embankment may push the upper structure made of building blocks from behind at this boundary surface, causing a gap between the upper structure made of foundation blocks and the lower structure made of foundation blocks. However, according to this configuration, the back-filling concrete cast behind the foundation block and the back-filling concrete cast behind the wall panel installed on the lowest stage are arranged in the stacking direction of the wall panel and the direction of the retaining wall. It can be made continuous without joints in both directions of laying extension. Therefore, unlike a retaining wall using conventional foundation blocks, a boundary surface is not formed between the lower structure consisting of the foundation blocks and the upper structure consisting of the wall panels installed on the lowest level. It becomes difficult to cause a gap between For this reason, the strength of the retaining wall increases and a stable retaining wall is constructed. Furthermore, since a continuous space is formed in both the stacking direction of the wall panels and the extension direction of the retaining wall, it is possible to place reinforcing bars that reinforce the strength of the backfill concrete continuously in this space. It becomes possible to improve the seismic performance of the retaining wall.

Further, the present invention is characterized in that the supporting leg has an opening formed in a surface facing the foundation ground.

According to this configuration, the back-filling concrete enters the opening formed in the surface of the support leg facing the foundation ground, and the opening is filled with the back-filling concrete to come into contact with the foundation ground. Therefore, the foundation block has an increased frictional force with respect to the foundation ground and an increased adhesion to the foundation ground, compared to a foundation block without openings. For this reason, the resistance that resists the force that tries to slide the foundation block and the backfill concrete placed behind it toward the front side of the retaining wall due to the earth pressure from the ground behind the backfill concrete and from the embankment. improve strength.

Further, the present invention is characterized in that a plurality of convex portions are formed on the surfaces of the standing leg portion and the supporting leg portion that are in contact with the foundation ground.

According to this configuration, the foundation block increases the frictional force with respect to the foundation ground due to the plurality of projections formed on the surface in contact with the foundation ground. For this reason, at the initial stage of foundation construction of a retaining wall, when the self-weight of the structure including the foundation block itself is light and the frictional force of the foundation block against the foundation ground is not sufficiently generated, backfill concrete is used behind it. When the wall is placed, the side pressure received from the back-filling concrete and the back-filling crushed stone pushes the retaining wall toward the front side of the retaining wall and improves the resistance to the sliding force.

In addition, the present invention is characterized in that the support leg has a notch formed in the horizontal direction at the end away from the standing leg.

According to this configuration, when pouring back-filling concrete behind the wall panel, the lower side of the flat plate-shaped drawing formwork used to separate the back-filling crushed stone provided behind the back-filling concrete is applied to the horizontal notch at the end of the support leg, so that there is no need to newly install a special spacing material or the like to keep the distance from the back of the panel below the drawing formwork. The thickness of the backfill concrete can be set to the desired thickness. The drawn-out formwork is pulled out from behind the backfill concrete after the backfill concrete has been installed.

Further, in the present invention, the support legs collapse as they move away from the standing legs, starting from a point located below the abutting point between the wall panels installed at the bottom of the retaining wall that is constructed in a curved line with a gradient. It is characterized by having slopes on both sides in the width direction.

According to this configuration, when the upper structure constructed on the upper part of the foundation part of the retaining wall is sloped and curved, the starting points of the slope that are recessed on both sides of the supporting legs of the adjacent foundation blocks are matched. By installing the foundation blocks in contact with each other, the foundation blocks can be easily installed with the same or substantially the same degree of opening as the opening between the lowermost wall panels. Therefore, unlike the conventional art, it is not necessary to calculate the gap between the adjacent foundation blocks each time according to the radius of the curved construction and the inclination of the superstructure. The foundation blocks can be installed without the need to install them apart. As a result, it is possible to reduce work setups when installing the foundation blocks, and to greatly improve the installation workability of the foundation blocks.

In the present invention, the starting point is a point closer to the standing leg than the point located below the abutting point between the wall panels installed at the bottom of the retaining wall constructed in a curved line with the smallest gradient. Both sides in the width direction are slanted so as to shrink away from the standing leg, and the attachment/detachment part for positioning the tip of the interval maintaining member below the abutting part between the wall panels installed at the bottom is slanted. The distance maintaining members are detachably provided at a plurality of locations corresponding to a plurality of slopes of the retaining wall constructed in a curved line having different distances from the upright portion on both sides marked with .

According to this configuration, among the detachable portions provided at a plurality of locations on both inclined sides of the support leg, the detachable portion provided at a location corresponding to the slope of the retaining wall to be constructed in a curve is provided with the interval maintaining member. The base blocks are installed side by side with the tips of the space maintaining members in contact with each other, so that the base blocks can be easily installed with the same or almost the same opening as the opening between the bottom wall panels. be able to. Therefore, even if the degree of inclination of the upper structure is changed, the inclination of the upper structure can be easily changed by simply changing the position of the attachment/detachment part for attaching the gap maintaining member without changing the shape of both sides of the foundation block. Base blocks can be placed in an arrangement according to size.

In addition, the present invention uses a design method based on experience that uses specified values without performing design calculations for the slope of a retaining wall with a height of 7 m or less, not including the height of the foundation, and the thickness of the backfill concrete. A method for constructing a retaining wall is constructed, in which a retaining wall is constructed using precast foundation blocks in which supporting legs extend in a direction that intersects the standing legs from a point spaced from the upper end by a predetermined distance.

A block retaining wall constructed using an empirical design method is not a retaining wall with a high degree of importance in which the cross-sectional shape is determined by design calculations. The restraint length is determined in advance based on the relationship of the slope and the condition of the back soil, and in principle it is used in places where the soil pressure is small, and on the premise that it is not used in important places. Such retaining walls can be constructed relatively easily and the cost can be minimized, but many of them are damaged by earthquakes and rainfall. However, according to the construction method of the retaining wall with this configuration, the backfilling concrete cast behind the foundation blocks and the backfilling concrete cast behind the wall panel installed at the lowest stage are different from the wall panel. It can be continuous without joints in both the stacking direction and the extension direction of the retaining wall. Therefore, no boundary surface is formed between the lower structure made up of the foundation blocks and the upper structure made up of the wall panels installed on the lowest stage, so that the lower structure and the upper structure are less likely to be misaligned. For this reason, even if the retaining wall is constructed using a design method based on experience, the strength of the retaining wall is increased, a stable retaining wall is constructed, and resistance to damage due to earthquakes and rainfall is improved.

According to the present invention, it can be used as a foundation for a retaining wall formed by installing a wall panel having a size, weight, or thickness that cannot resist the lateral pressure received from the backfill concrete and moves, and moreover, , precast foundation blocks that can be easily positioned relative to the wall panels stacked above them.

1 shows a precast foundation block according to a first embodiment of the invention; FIG. FIG. 2 is a cross-sectional view showing a method of constructing the foundation of a retaining wall using the foundation blocks shown in FIG. 1; 1. It is the perspective view which looked down from diagonally upward during construction of the retaining wall constructed by piling up a wall panel in multiple stages on the foundation block shown in FIG. FIG. 2 is a cross-sectional view of a retaining wall constructed by stacking wall panels in multiple stages on the foundation block shown in FIG. 1 ; (a), (b), and (c) show the slope of the supporting leg that collapses at a certain angle as it moves away from the standing leg when constructing a retaining wall with a 5-minute slope, a 4-minute slope, and a 3-minute slope. Plan views of the foundation blocks shown in FIG. 1 attached to both sides in the width direction. FIG. 10 is a plan view of a precast foundation block according to a modification of the first embodiment in which both sides in the width direction of the support legs are sloped so as to contract at different angles as they move away from the base. (a) is a side view of the lowermost wall panel stacked on the foundation block shown in FIG. 5(d) is a side view of a state in which the lowest wall panel is piled up on the foundation block with a gradient of 5 minutes, and (d) is a plan view of that state. (a) is a side view of the lowermost wall panel stacked on the foundation block shown in FIG. 5 (b) with a slope of 4 minutes; 5(d) is a side view of a state in which the lowermost wall panel is stacked on the foundation block shown in 5(e) with a slope of 4 minutes, and 5(d) is a plan view of the state. (a) is a side view of the lowermost wall panel stacked on the foundation block shown in FIG. 5(d) is a side view of a state in which the lowermost wall panel is stacked on the foundation block shown in 5(f) with an inclination of 3 minutes, and 5(d) is a plan view of the state. Figure 4 shows a precast foundation block according to a second embodiment of the invention; FIG. 10 is a perspective view of a retaining wall constructed by piling up wall panels in multiple stages on the foundation block shown in FIG. 9 , looking down obliquely from above during construction. FIG. 10 is a cross-sectional view of a retaining wall constructed by stacking wall panels in multiple stages on the foundation block shown in FIG. 9 ; Figure 3 shows a precast foundation block according to a third embodiment of the invention; FIG. 13 is a perspective view of a retaining wall constructed by piling up wall panels in multiple stages on the foundation block shown in FIG. 12 , looking down obliquely from above during construction. FIG. 13 is a cross-sectional view of a retaining wall constructed by stacking wall panels in multiple stages on the foundation block shown in FIG. 12 ;

Next, a first embodiment of a precast foundation block according to the invention will be described.

FIG. 1(a) is a front view of a precast base block 1A according to the first embodiment of the present invention, and FIG. 1(b), (c), (d), (e) and (f) are the base block 1A 1 is a plan view, a side view, a perspective view, a rear view and a bottom view of the.

The foundation block 1A is formed in advance by integrally molding concrete with a molding die in a factory, and at the site where the retaining wall is constructed, a wall panel 13 (see FIG. 2) is installed above it as will be described later to form the retaining wall. foundation for the wall. The wall panel 13 has such a size, weight, or thickness that it cannot withstand the lateral pressure received from the back-filling concrete 17 placed on the rear surface of the panel and moves. Further, the retaining wall constructed by the foundation blocks 1A and the wall panel 13 is constructed according to the guidelines for retaining wall construction established by the Japan Road Association, an incorporated association. In this retaining wall construction guideline, a design method based on experience is used, using specified values without design calculations for the slope of a retaining wall with a height of 7m or less, not including the height of the foundation, and the thickness of the backfill concrete. and build a retaining wall.

The foundation block 1A is composed of an upright portion 1a on which the wall panel 13 is installed and a support leg portion 1b that supports the upright portion 1a. The supporting leg portion 1b extends in a direction intersecting the standing leg portion 1a. It extends in a direction perpendicular to the A pair of embedded nuts 2 is embedded at a predetermined position at the extending end of the support leg portion 1b, as shown in detail in the partially enlarged view surrounded by the dotted circle in FIG. 1(c). Each embedded nut 2 is screwed with one end of a threaded rod 3 which is formed by carving a male thread on the outer circumference of a reinforcing bar. For this reason, a pair of threaded rods 3 are detachably erected at the extending end of the support leg portion 1b. The threaded rod 3 constitutes a fixing member for fixing a later-described overturn prevention member 14 (see FIG. 2) that prevents the wall panel 13 above the foundation block 1A from overturning.

Further, the supporting leg portion 1b has three rectangular openings 1c formed on the surface facing the foundation ground on which the retaining wall is constructed. The opening 1c is formed such that the lower surface facing the foundation ground is wider than the upper surface on which the screw rod 3 is erected, and the side wall surfaces of the support legs 1b surrounding the opening 1c are inclined to form an opening. The space formed in the portion 1c is in the shape of a quadrangular pyramid lacking the apex. Moreover, as shown in FIG. 1(f), each of the standing leg portion 1a and the supporting leg portion 1b has a plurality of convex portions 1d formed on the surface thereof in contact with the foundation ground. The convex portion 1d has a dome shape in this embodiment. The support leg 1b is formed with a notch 1e that is cut in the horizontal direction at the end portion away from the standing leg 1a. As will be described later, the notch 1e is brought into contact with the end of the drawing mold 15 (see FIG. 2), and the notch 1e is used for positioning the drawing mold 15. As shown in FIG.

The head of the standing leg portion 1a is inclined to protrude toward the supporting leg portion 1b. A pair of embedded nuts 4 are embedded in the inclined wall surface. Each embedded nut 4 is provided at the same interval as the standing interval of the screw rods 3, and the axial center of each embedded nut 4 is directed to each opposing screw rod 3. - 特許庁These embedded nuts 4 are screwed with bolts 6 for fixing a connecting member 7 (see FIG. 2), which will be described later, to the head of the upright portion 1a. In addition, three holes 5 each having a predetermined depth are provided on both sides of the supporting leg portion 1b. A pin 21 (see FIG. 5), which will be described later, is inserted into this hole 5 as a spacing maintaining member. It is used when constructing a retaining wall in a curved line in the extension direction.

2(a) to 2(e) are cross-sectional views showing a method of constructing the foundation of a retaining wall on the bottom of a valley using the foundation block 1A. FIG. 3 is a perspective view of a retaining wall constructed by piling up wall panels 13 on foundation blocks 1A in multiple stages, looking down obliquely from above during construction.

As shown in FIG. 2(a), the foundation block 1A is installed on the foundation crushed stone 12 laid on the ground 11 of the valley bottom. One end of each of a pair of connecting members 7 is attached by embedded nuts 4 and bolts 6 to the head of the upright leg 1a of the foundation block 1A. The other end of the connecting member 7, one end of which is attached to the head of the standing leg 1a, protrudes upward from the upper end of the standing leg 1a. The wall panel 13 stacked on the foundation block 1A is made of a thin concrete panel, and is formed into a rectangular shape by pouring concrete into a formwork for forming the panel. A pair of embedded nuts are embedded respectively in the upper and lower portions of the back surface of the wall panel 1A, and as shown in FIG. Mounted on the back. Therefore, the other ends of the two connecting members 7 protrude from the upper end of the wall panel 13, and the other ends of the two connecting members 7 also protrude from the lower end.

The connecting member 7 has a shape in which a rectangular plate material is bent in the lateral direction in a U-shape toward the back surface of the panel or the inclined wall surface of the upright portion 1a, and is attached to the back surface of the panel or the inclined wall surface of the upright portion 1a. The bending height at one end of the side to be bent is formed high, and the high foot portion 7a with this high bending height contacts the inclined wall surface of the panel back surface or the standing leg portion 1a, and the bolt 6 tilts the panel back surface and the standing leg portion 1a. Wall mounted. As a result, the other end on the opposite side of the connecting member 7 provided on the wall panel 13 protrudes upward or downward from the upper end or the lower end of the wall panel 13, creating a gap between the rear surface of the vertically adjacent wall panel 13. Form. The opposite end of the connecting member 7 provided on the upright portion 1a protrudes upward from the upper end of the upright portion 1a to form a gap with the back surface of the wall panel 13 at the lowest stage. A bolt 8 is screwed to the opposite end of the connecting member 7. By adjusting the amount of projection of the tip of the bolt 8 toward the back side of the panel or the side of the inclined wall surface of the upright leg 1a, the connection can be achieved. The other end on the opposite side of the member 7 is engaged via a bolt 8 with the rear surface of the vertically adjacent wall panel 13 or the inclined wall surface of the upright portion 1a.

As shown in FIG. 2(a), above the foundation block 1A placed on the crushed stone foundation 12, the connection member 7 provided at the upper end of the standing leg portion 1a and the lower end of the wall panel 13 at the lowest stage are provided. The lowermost wall panel 13 is piled up by the connecting member 7. As shown in FIG. At this time, the end portion of the connecting member 7 provided at the upper end of the standing leg portion 1a, which protrudes upward, abuts the back surface of the panel body of the lowermost wall panel 13 via the bolt 8, and the lowermost wall panel 13 , and the downward projecting end of the connecting member 7 provided on the lowermost wall panel 13 abuts the inclined wall surface of the standing leg portion 1a via the bolt 8, thereby pressing the inclined wall surface of the standing leg portion 1a. hold down As a result, the force of the lowermost wall panel 13 falling toward the back of the wall surface is received by the back surface of the lowermost wall panel 13 and the inclined wall surface of the upright portion 1a via the bolt 8 and the connecting member 7, thereby The panel 13 stands on its own on the base block 1A.

Next, as shown in FIG. 2(b), each bolt 6 for attaching the connecting member 7 to the rear surface of the lowermost wall panel 13 and the screw rod 3 erected on the support leg 1b of the foundation block 1A. An anti-falling member 14 is welded between them to prevent the lowermost wall panel 13 from falling. As shown in the figure, the screw rod 3 that constitutes the fixing member is attached to the support leg 1b behind the standing leg 1a rather than the point A where the fall prevention member 14 is attached to the upper part of the wall panel 13 installed on the lowest stage. be provided.

Next, as shown in FIG. 2(c), the lower end of the flat plate-shaped drawing mold 15 is brought into contact with the notch 1e provided at the end of the support leg 1b, and the drawing mold 15 is pulled out. A space formed on the back side is partitioned. Then, with a support rod (not shown) provided between the back surface of the wall panel 13 and the front surface of the drawing mold 15, the height of the drawing mold 15 is set in the space formed on the back side of the drawing mold 15. The backfilling crushed stone 16 is thrown within the range of .

Next, as shown in FIG. 2(d), the connection member 7 attached to the upper end of the wall panel 13 does not reach the space formed between the back surface of the wall panel 13 and the front surface of the drawing formwork 15. The backfill concrete 17 is placed up to the height shown. At this time, the backfill concrete 17 enters the opening 1c formed in the support leg 1b of the foundation block 1A, fills the opening 1c, and contacts the crushed foundation stone 12 below. In the backing concrete 17, the horizontal joint surface of the concrete is high on the wall panel 13 side and has a step 17a that is low on the opposite side. It is formed. When the back-filling concrete 17 is placed, the back-filling concrete 17 is provided with reinforcing bars (not shown). At least one reinforcing bar is provided through each of the backing concrete 17 that is joined to the wall panel 13 side and the opposite side thereof. A reinforcing bar 18 is embedded in the backfill concrete 17 with one end exposed. One end of a fall prevention member 14 is fixed to the exposed reinforcing bar 18 to prevent the wall panel 13 of the next stage from falling. After the back-filling concrete 17 hardens, as indicated by the arrow in FIG. 2(e), the pull-out formwork 15 is pulled out obliquely upward from behind the back-filling concrete 17 to construct the foundation of the retaining wall.

Next, as shown in FIG. 3, the wall panel 13 of the second stage is stacked above the wall panel 13 of the lowest stage. In the second and subsequent wall panels 13, the ends of the connecting members 7 provided on the lower wall panel 13 and protruding upward from the lower wall panel 13 come into contact with the rear surface of the upper wall panel 13 via bolts 8. The end portion of the connecting member 7 provided on the upper wall panel 13 protruding downward from the upper wall panel 13 is attached to the rear surface of the lower wall panel 13 by a bolt 8. , and presses the back surface of the lower wall panel 13 . As a result, the force of the upper wall panel 13 falling toward the wall surface rear side is received by the rear surface of each of the upper and lower wall panels 13 via the bolt 8 and the connecting member 7, and the upper wall panel 13 becomes the lower wall panel. Upper and lower wall panels 13, which stand on the wall 13 and are vertically adjacent to each other, are obliquely piled up in a plurality of stages.

In addition, in this embodiment, the case where the wall surface is bent in the laying extension direction and curved construction is described. For this reason, a gap is provided between the other end of the connecting member 7 protruding from the wall panel 13 and the back surface of the panel, and the bolt 8 is protruded into this gap and the tip of the bolt 8 is brought into contact with the back surface of the panel. However, when the wall surface is constructed in a straight line in the laying extension direction, the panel surface of the wall surface panel 13 of each stage becomes flush, and a gap is provided between the other end portion on the opposite side of the connecting member 7 and the back surface of the panel. No need to set. For this reason, it is possible to use a connecting member 7 that is attached to the rear surface of the panel and does not have the high leg portion 7a at one end. In this case, the opposite end of the connecting member 7 is directly engaged with the rear surface of the vertically adjacent wall panel 13, so the bolt 8 becomes unnecessary.

In the present embodiment, two rows of protrusions 13a are sparsely arranged in parallel on the rear surface of the wall panel 13 along the vertical direction, which is the stacking direction of the wall panel 13 . These protrusions 13a are formed at predetermined intervals from the panel upper end and the panel lower end in the stacking direction of the wall panel 13 . Four recesses 13b are formed around each projection 13a. The wall panel 13 is integrated with the back-filling concrete 17 placed behind it by the projections 13a and the recesses 13b. The bolts 6 for attaching the connecting members 7 to the rear surface of the wall panel 13 are embedded in the back-filling concrete 17 at the ends protruding from the rear surface of the panel and fixed, so that the wall panel 13 is fixed to the back-filling concrete 17. Anchor material for fixing to the front.

The wall panel 13 on each stage, which is made to stand by the connecting member 7, is provided between each bolt 6 that attaches one end of the connecting member 7 to the upper and lower ends of the rear surface of the wall panel 13, and the reinforcing bars 18 exposed in the backfill concrete 17 behind the bolts. A tipping prevention member 14 is welded and provided to prevent tipping. Backfilling crushed stone 16 and backfilling concrete 17 are successively layered behind the wall panel 13 in each step in a state in which overturning is prevented, and the wall panel 13 constructs a retaining wall.

FIG. 4 is a sectional view of a retaining wall 19A constructed by piling up wall panels 13 in this way. 2 and 3 are assigned the same reference numerals, and descriptions thereof will be omitted. The retaining wall 19A is constructed with the foundation block 1A installed on the crushed foundation stone 12 as a foundation, and holds the wall panel 13, the connection member 7, and the panel main body of the wall panel 13 of each tier. Anti-overturn members 14 to prevent the panel 13 from overturning, and the back surface of the wall panel 13 on each level is formed in a plurality of layers that are successively poured and buried together with the overturn-preventing member 14 to a predetermined height. Back-filling concrete 17 formed so that the joint surface is high on the side of the wall panel 13 and low on the opposite side, forming a step 17a extending in the extension direction of the retaining wall 19A, and the side of the wall panel 13 and its opposite side. It is constructed with at least one reinforcing steel bar each passing through the backfill concrete 17 and the backfill crushed stone 16 which are spliced side by side. In addition, illustration of a reinforcing bar is abbreviate|omitted in the same figure. Further, the retaining wall 19A shown in the figure has a 5-minute gradient of 1:0.5 rising to a height of 1 m at a point 50 cm away in the horizontal direction.

FIG. 5(a) is a plan view of the foundation block 1A when constructing the retaining wall 19A with this 5-minute slope. In addition, the figure (b) shows a 4-minute gradient of 1:0.4 rising to a height of 1 m at a point 40 cm away in the horizontal direction, and the figure (c) shows a 1 m gradient at a point 30 cm away in the horizontal direction. It is a top view of foundation block 1A at the time of constructing retaining wall 19A with a 3-minute gradient of 1:0.3 rising to height. As described above, three holes 5 are formed on both sides of the support leg portion 1b of the foundation block 1A, respectively. A pin 21 is inserted as a spacing member into the hole 5 farthest from the upright portion 1a. Further, when the retaining wall 19A is constructed with a 4-minute slope as shown in FIG. Further, when the retaining wall 19A is constructed with a 3-minute slope as shown in FIG. The locations marked with circles in FIG. 5 indicate locations where the adjacent base blocks 1A abut against each other.

FIG. 6(a) is a side view of a state in which the lowest wall panel 13 is stacked on the foundation block 1A shown in FIG. 5(a) with an inclination of 5 minutes, and FIG. It is a diagram. FIG. 7(a) is a side view of a state in which the lowest wall panel 13 is stacked on the foundation block 1A shown in FIG. 5(b) with a slope of 4 minutes, and FIG. 7(b) is a plan view of that state. be. FIG. 8(a) is a side view of a state in which the lowest wall panel 13 is stacked on the foundation block 1A shown in FIG. 5(c) with a slope of 3 minutes, and FIG. 8(b) is a plan view of that state. be. In FIGS. 5 to 8, the same reference numerals are given to the same or corresponding parts as those in FIGS. 1 and 2, and the description thereof will be omitted.

As shown in FIGS. 6(b), 7(b) and 8(b), when the radius R of the curve drawn by the foundation block 1A in the laying extension direction is constant, the adjacent foundation block 1A and the adjacent lowest level The sizes of the gaps s1, s2 and s3 similarly generated between the wall panels 13 differ according to the slope of the retaining wall 19A. The magnitudes of these gaps s1, s2 and s3 become smaller (s1>s2>s3) for smaller gradients of 5, 4 and 3 minutes.

In this embodiment, the supporting leg portion 1b of the base block 1A is provided with an inclination that shrinks away from the standing leg portion 1a on both side portions in the width direction of the supporting leg portion 1b. This inclination is from the point C3 located below the contact point B3 between the wall panels 13 installed at the bottom of the retaining wall 19A shown in FIG. The point D (see FIGS. 5(a) to 5(c)), which is close to 1a, is set as a starting point. In addition, holes 5 for positioning the tips of pins 21, which are gap maintaining members, are located at respective locations C1, C2, and C3 located below the contact locations B1, B2, and B3 between the wall panels 13 installed at the bottom. Detachable portions are provided on both sides. Each hole 5 is provided with pins 21 at three locations on both inclined sides corresponding to 5-, 4-, and 3-minute slopes of the retaining wall 19A constructed in a curved line and having different distances from the upright portion 1a. is detachably provided. FIGS. 6(b), 7(b) and 8(b) show part of the contact points between the pins 21 of the adjacent base blocks 1A and the positions of the holes 5 into which the pins 21 are inserted. A partial enlarged view of an enlarged view is shown.

When constructing the retaining wall 19A with an inclination of 5 minutes, as shown in FIG. 2, the tips of the pins 21 are brought into contact with each other, and the foundation blocks 1A are arranged along the curve previously drawn on the crushed foundation stone 12 according to the slope of the retaining wall 19A. Also, when building the retaining wall 19A with a slope of 4 minutes, as shown in FIG. As shown in (b), the tips of the pins 21 are brought into contact with each other, and the foundation blocks 1A are arranged along the curve previously drawn on the crushed stone foundation 12 according to the slope of the retaining wall 19A. Further, when the retaining wall 19A is constructed with an inclination of 3 minutes, as shown in FIG. As shown in b), the tips of the pins 21 are brought into contact with each other, and the foundation blocks 1A are arranged along the curve previously drawn on the crushed stone foundation 12 according to the slope of the retaining wall 19A.

In this embodiment, both sides of the support leg 1b are inclined at a certain angle regardless of the slope of the retaining wall 19A, and the positions of the holes 5 into which the pins 21 are inserted are changed to match the slope of the retaining wall 19A. The basic blocks 1A are arranged as shown. However, as shown in FIGS. 5(d), (e), and (f), the width direction of the support leg 1b is changed according to the slope of the retaining wall 19A, which is shrunk at different angles as the distance from the upright leg 1a increases. The base blocks 1A1, 1A2 and 1A3 may be arranged side by side by being attached to both sides. In this case, the holes 5 are not provided on both side portions in the width direction of the support leg portion 1b.

FIG. 6(c) is a side view of the bottom wall panel 13 stacked on the foundation block 1A1 shown in FIG. 5(d) with a gradient of 5 minutes, and FIG. 6(b) is a plan view of that state. be. FIG. 7(c) is a side view of the bottom wall panel 13 stacked on the base block 1A2 shown in FIG. 5(e) with a slope of 4 minutes, and FIG. 7(d) is a plan view of that state. be. FIG. 8(c) is a side view of the bottom wall panel 13 stacked on the foundation block 1A3 shown in FIG. 5(f) with a slope of 3 minutes, and FIG. 8(d) is a plan view of that state. be.

On both sides of the support leg portion 1b in the width direction, portions located below the contact portions B1, B2, and B3 of the wall panels 13 installed at the bottom of the retaining wall 19A constructed in a curved line with a slope. With C1, C2, and C3 as starting points, there is a slope that shrinks away from the upright portion 1a. FIGS. 6(d), 7(d) and 8(d) show partially enlarged contact points between the starting points of the inclinations attached to both sides of the adjacent base blocks 1A1, 1A2 and 1A3. A partially enlarged view is shown.

When constructing the retaining wall 19A with a slope of 5 minutes, the foundation block 1A1 shown in FIG. 5(d) is used, and as shown in FIG. The base blocks 1A1 are arranged along the curve drawn in advance on the crushed foundation stone 12 according to the gradient of the retaining wall 19A, with the starting points of the slopes attached to the portions in contact with each other. Further, when building the retaining wall 19A with a slope of 4 minutes, the foundation block 1A2 shown in FIG. 5(e) is used, and as shown in FIG. The base blocks 1A2 are arranged along the curve previously drawn on the crushed stone 12 according to the slope of the retaining wall 19A, with the starting points of the slopes attached to both sides of the retaining wall 19A in contact with each other. Further, when building the retaining wall 19A with a slope of 3 minutes, the foundation block 1A3 shown in FIG. 5(f) is used, and as shown in FIG. The base blocks 1A3 are arranged along the curve previously drawn on the crushed stone 12 according to the slope of the retaining wall 19A, with the starting points of the slopes attached to both sides of the retaining wall 19A in contact with each other.

According to the base block 1A according to this embodiment, as shown in FIG. 1, the screw rod 3 constituting the fixing member is provided on the support leg portion 1b, so that the base block 1A can be mounted as shown in FIG. A fall prevention member 14 can be provided between the back surface of the wall panel 13 installed above and the screw rod 3 . Since the wall panel 13 has a size, weight, or thickness that cannot withstand the lateral pressure received from the back-filling concrete 17 and moves, even if the wall panel 13 is made larger than the conventional building block, it is light in weight and easy to handle. , the number used per unit area can be greatly reduced. The operation of installing a small number of such wall panels 13 above the foundation block 1A using the overturn prevention member 14 is a simple operation that does not require time and manpower. For this reason, the wall panel 13 having a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete 17 and can be moved can be easily installed upward with good workability and used as the foundation of the retaining wall 19A. , the precast foundation block 1A that can reduce the construction cost of the retaining wall 19A can be provided. Further, since the screw rod 3 is provided at a predetermined position of the support leg 1b, the installation position of the screw rod 3 can be calculated each time in consideration of the relative position between the wall panel 13 installed above and the base block 1A. Therefore, the wall panel 13 can be installed above the base block 1A accurately and efficiently.

Further, according to the base block 1A according to the present embodiment, the threaded rods 3 are detachably attached to the support legs 1b, so that the base block 1A can be molded without the threaded rods 3. Easier to manufacture. In addition, the handling of the base block 1A during storage and transportation becomes easier.

In the present embodiment, the wall panel 13 is engaged with the upright portion 1a by the connecting member 7, so that the wall panel 13 is independently connected to the upright portion 1a, as shown in FIG. Therefore, according to the foundation block 1A of the present embodiment, when the overturn prevention member 14 is provided between the back surface of the wall panel 13 and the threaded rod 3, the wall panel 14 can stand on its own on the upper end of the upright portion 1a. can. Therefore, when the overturn prevention member 14 is provided, the wall panel 13 is allowed to stand on its own at the upper end of the upright portion 1a. The construction process of 19 A of retaining walls is simplified, and reduction of the construction cost of 19 A of retaining walls can be achieved.

In this embodiment, the wall panel 13 is engaged with the upright portion 1a by the connecting member 7, and the wall panel 14 is made independent on the upper end of the upright portion 1a. However, by providing a protruding pin at the lower end of the wall panel 13 or the upper end of the upright portion 1a and providing a hole in which the pin fits in the upper end of the upright portion 1a or the lower end of the wall panel 13, the pin can be engaged with the hole. The lower end of the wall panel 13 may be aligned with the upper end of the upright portion 1a by fitting them together. According to this configuration, when the overturn prevention member 14 is provided between the back surface of the wall panel 13 and the screw rod 3, the lower end of the wall panel 13 can be positioned at the upper end of the upright portion 1a of the foundation block 1A. Therefore, when installing the overturn prevention member 14, it is easy to align the lower end of the wall panel 13 with the upper end of the upright portion 1a without shifting, and to provide a support material for holding the wall panel 13 above the base block 1A. and the workability of the construction work of the retaining wall 19A is improved.

Further, in the present embodiment, as described above, the threaded rod 3 that constitutes the fixing member is attached to the portion A where the overturn prevention member 14 is attached to the upper part of the wall panel 13 installed on the lowest stage (see FIG. 2(b)). It is provided on the support leg 1b on the rear side away from the upright leg 1a. If the screw rod 3 is provided on the support leg 1b at a position closer to the standing leg 1a than the attachment point A of the overturn prevention member 14 to the upper part of the wall panel 13 installed on the lowest stage, the wall panel 13 Although it is possible to prevent overturning toward the front side of the wall surface, overturning toward the rear side of the wall surface cannot be effectively prevented. However, according to the foundation block 1A according to the present embodiment, the overturn prevention member 14 can effectively prevent the wall panel 13 from overturning toward the front side of the wall surface and overturning toward the rear side of the wall surface.

Further, in the conventional foundation block disclosed in Patent Document 1, the foundation portion of the retaining wall 19A is constructed by placing the foundation block and then pouring concrete into the opening of the foundation block for curing. . After that, the lowermost building blocks are placed on the foundation blocks, and backfill concrete is placed behind them for curing to build up the lowermost building blocks. However, according to the foundation block 1A according to the present embodiment, the support leg portion 1b extends in a direction intersecting the standing leg portion 1a from a position at a predetermined distance d1 (see FIG. 1(c)) from the upper end of the standing leg portion 1a. Therefore, as shown in FIG. 3, a space is formed connecting the back of the standing leg portion 1a with a predetermined interval d1 and the back of the wall panel 13 installed at the bottom. Therefore, by placing the back-filling concrete 17 in this space, the back-filling concrete 17 is simultaneously formed behind the foundation block 1A and behind the wall panel 13 installed on the lowest stage, and the back-filling concrete 17 is formed behind the foundation block 1A. The construction part and the construction part of the wall panel 13 installed at the lowest stage are constructed by placing concrete once and curing it once. For this reason, the construction process for constructing the retaining wall 19A can be reduced.

In conventional foundation blocks, a boundary surface is structurally formed between the upper surface of the foundation block and the backfill concrete that is cast behind the building blocks on the lowest level. Earth pressure from the embankment may push the upper structure made of building blocks from behind at this boundary surface, causing a gap between the upper structure made of foundation blocks and the lower structure made of foundation blocks. However, according to the foundation block 1A according to the present embodiment, the back-filling concrete 17 cast behind the foundation block 1A and the back-filling concrete 17 cast behind the wall panel 13 installed at the lowest level are separated. The wall panel 13 is stacked and the retaining wall 19A is laid and extended in both directions without joints. Therefore, unlike a conventional retaining wall using foundation blocks, no boundary surface is formed between the lower structure made up of the foundation blocks 1A and the upper structure made up of the wall panel 13 installed on the lowest stage. It becomes difficult to cause misalignment with the upper structure. Therefore, the strength of the retaining wall 19A is increased and a stable retaining wall 19A is constructed. Furthermore, since a space is formed behind the foundation block 1A and the wall panel 13, which is continuous in both the stacking direction of the wall panel 13 and the laying extension direction of the retaining wall 19A, the backfill concrete 17 is continuously formed in this space. Reinforcing reinforcing bars can be placed to reinforce the strength, and the seismic performance of the retaining wall 19A can be improved.

Further, according to the foundation block 1A according to the present embodiment, the opening 1c (see FIG. 1(d)) formed in the surface of the supporting leg 1b facing the foundation ground is provided with the openings 1c shown in FIGS. As shown in , the back-filling concrete 17 enters, filling the opening 1c with the back-filling concrete 17 and coming into contact with the foundation ground. Therefore, the foundation block 1A has an increased frictional force with respect to the foundation ground and an increased adhesion to the foundation ground, compared to a foundation block without the opening 1c. For this reason, the foundation block 1A and the backfilling concrete 17 cast behind it are pushed toward the front side of the retaining wall 19A by the earth pressure from the ground or embankment behind the backfilling concrete 17, and the force tends to slide. Increases resistance to

Further, according to the foundation block 1A according to the present embodiment, the plurality of protrusions 1d (see FIG. 1(f)) formed on the surface of the foundation block 1A in contact with the foundation ground increases the frictional force against the foundation ground. For this reason, the foundation block 1A is used at the initial stage of construction of the foundation of the retaining wall 19A, when the self-weight of the structure including the foundation block 1A itself is light and the frictional force of the foundation block 1A against the foundation ground is not sufficiently generated. When the back-filling concrete 17 is placed in the back, the side pressure received from the back-filling concrete 17 and the back-filling crushed stone 16 improves the resistance force against the force that is pushed to the front side of the retaining wall 19A and tries to slide. .

Further, according to the foundation block 1A according to the present embodiment, when the backfill concrete 17 is placed behind the wall panel 13, in order to separate the backfill crushed stone 16 provided behind the backfill concrete 17, As shown in FIG. 2(c), the lower side of the flat drawing mold 15 to be used is cut horizontally into the notch 1e (see FIG. 1(d)) at the end of the support leg 1b. The thickness of the backfill concrete 17 can be set to the required thickness without newly providing a special space maintaining material or the like to keep the distance from the back surface of the panel under the drawing form 15. .

Further, according to the base block 1A according to this embodiment, as shown in FIGS. 5, pin 21 is attached to hole 5 provided at a location corresponding to each slope of 5 minutes, 4 minutes and 3 minutes of curved retaining wall 19A, FIG. 6 (b), FIG. As shown in FIG. 8(b), by abutting the tips of these pins 21 and arranging the foundation blocks 1A side by side, the opening between the bottom wall panels 13 is the same or almost the same. The foundation block 1A can be easily installed in the opening. Therefore, even if the degree of inclination of the upper structure changes, the inclination of the upper structure can be easily changed by simply changing the position of the hole 5 for mounting the pin 21 without changing the shape of both sides of the base block 1A. The base blocks 1A can be installed in an arrangement according to the size. Therefore, unlike the conventional art, it is not necessary to calculate the gap between the adjacent foundation blocks 1A each time according to the magnitude of the radius of the curved construction and the magnitude of the inclination of the upper structure. The foundation blocks 1A can be installed without the need to install them apart from each other. For this reason, it is possible to reduce work setups when installing the foundation block 1A, and to greatly improve the installation workability of the foundation block 1A.

Further, according to the foundation blocks 1A1, 1A2, and 1A3 shown in FIGS. 6(d) and 7( d) and by installing the foundation blocks 1A1, 1A2 and 1A3 in contact with each other as shown in FIG. Blocks 1A1, 1A2 and 1A3 can be installed. Therefore, with these foundation blocks 1A1, 1A2 and 1A3, similarly to the foundation block 1A, it is possible to reduce work preparations during the installation work of the foundation blocks 1A1, 1A2 and 1A3. significantly improved.

In addition, block retaining walls constructed using design methods based on experience according to the above-mentioned retaining wall construction guidelines are not highly important retaining walls whose cross-sectional shape is determined by design calculations. In principle, it should be used where the soil pressure is small, and should not be used where it is important. is assumed. Such retaining walls can be constructed relatively easily and the cost can be minimized, but many of them are damaged by earthquakes and rainfall. However, according to the retaining wall 19A according to this embodiment, the backfill concrete 17 is cast behind the foundation block 1A or 1A1, 1A2 or 1A3, and the wall panel 13 is placed at the bottom. The back-filling concrete 17 is continuous without joints in both the stacking direction of the wall panel 13 and the laying extending direction of the retaining wall 19A.

Therefore, no boundary surface is formed between the lower structure consisting of the foundation blocks 1A or 1A1, 1A2 or 1A3 and the upper structure consisting of the wall panel 13 installed on the lowest stage, and a gap occurs between the lower structure and the upper structure. it gets harder. For this reason, even if the retaining wall 19A is constructed using a design method based on experience, the strength of the retaining wall 19A is increased and a stable retaining wall 19A is constructed, thereby improving resistance to damage due to earthquakes and rainfall. Furthermore, since a space is formed behind the foundation block 1A and the wall panel 13, which is continuous in both the stacking direction of the wall panel 13 and the laying extension direction of the retaining wall 19A, the backfill concrete 17 is continuously formed in this space. It becomes possible to arrange reinforcing bars for reinforcing the strength of the retaining wall 19A, thereby improving the seismic performance of the retaining wall 19A.

FIG. 9(a) is a front view of a precast base block 1B according to the second embodiment of the present invention, and FIG. 9(b), (c), (d) and (e) are plan views of the base block 1B; They are a side view, a perspective view and a rear view. In the figure, the same reference numerals are given to the same or corresponding parts as those in FIG. 1, and the description thereof will be omitted.

In the base block 1A according to the first embodiment, the support leg 1b extends in a direction perpendicular to the upright portion 1a from the upper end of the upright portion 1a at a predetermined distance d1. However, in the base block 1B according to the second embodiment, the support leg 1f extends from the upper end of the upright portion 1a at a predetermined distance d2 (d2<d1), and extends from the upright portion 1a at a predetermined angle. It extends in the direction forming In addition, in the foundation block 1A according to the first embodiment, the support legs 1b are provided with a large rectangular opening 1c and elongated rectangular openings 1c on both sides thereof on the surface facing the foundation ground on which the retaining wall is laid. were formed at three locations. However, in the foundation block 1B according to the second embodiment, the support legs 1f have two large rectangular openings 1g formed side by side on the surface facing the foundation ground on which the retaining wall is laid. there is Further, in the foundation block 1A according to the above-described first embodiment, the standing leg portion 1a and the supporting leg portion 1b have a plurality of convex portions 1d formed on the surfaces in contact with the foundation ground. However, in the foundation block 1B according to the second embodiment, the upright portion 1a and the support leg portion 1f do not have the convex portion 1d formed on the surface in contact with the foundation ground. A base block 1B according to the second embodiment has the same configuration as the base block 1A according to the first embodiment except for these points.

The foundation block 1B according to the second embodiment, like the foundation block 1A according to the first embodiment, is also installed on foundation crushed stone 12 on the ground 11 as shown in FIG. . FIG. 10 is a perspective view looking down obliquely from above during construction of a retaining wall constructed by piling up wall panels 13 in multiple stages on foundation blocks 1B in this foundation. In the figure, the same reference numerals are given to the same or corresponding parts as those in FIGS. 3 and 9, and the description thereof will be omitted. Moreover, FIG. 11 is sectional drawing of the retaining wall 19B constructed by piling up the wall panel 13 on the foundation block 1B. 4 and 10 are denoted by the same reference numerals, and description thereof will be omitted. The retaining wall 19B is constructed with the foundation block 1B as its base, for example, with a 5-minute gradient of 1:0.5 as shown in FIG.

In this retaining wall 19B as well, since the support leg 1f extends in a direction intersecting the standing leg 1a from a position spaced from the upper end of the standing leg 1a at a predetermined distance d2, the supporting leg 1f extends behind the standing leg 1a at a predetermined distance d2. A space is formed connected to the back of the wall panel 13 installed at the bottom. Therefore, by pouring the back-filling concrete 17 into this space, the back-filling concrete 17 is simultaneously formed behind the foundation block 1B and behind the wall panel 13 installed on the lowest stage, and the back-filling concrete 17 is formed behind the foundation block 1B. The construction part and the construction part of the wall panel 13 installed at the lowest stage are constructed by placing concrete once and curing it once. In addition, the back-filling concrete 17 is formed in a plurality of layers that are sequentially poured and buried in the back surface of the wall panel 13 of each stage together with the overturn prevention member 14 to a predetermined height. The step 17a is formed so that one side is high and the other side is low, and the step 17a extends in the extension direction of the retaining wall 19B.

According to the foundation block 1B according to the second embodiment, a plurality of protrusions 1d are formed on the surface of the foundation block 1A according to the first embodiment, in which the standing leg portion 1a and the supporting leg portion 1b are in contact with the foundation ground. The action and effect achieved by this are not exhibited. However, other than that, it is possible to provide the precast foundation block 1B that has the same effects as the foundation block 1A according to the first embodiment, and that can reduce the construction cost of the retaining wall 19B.

In addition, unlike the support leg portion 1b according to the first embodiment, the support leg portion 1f has a surface facing the foundation ground on which the retaining wall is constructed. do. Therefore, the back-filling concrete 17 enters this space and fills this space with the back-filling concrete 17, thereby increasing the area of the back-filling concrete 17 in contact with the foundation ground. Therefore, compared with the foundation block 1A according to the first embodiment, the foundation block 1B has an increased frictional force with respect to the foundation ground, and further increases the adhesion to the foundation ground. For this reason, the foundation block 1B and the backfilling concrete 17 cast behind it are pushed toward the front side of the retaining wall 19B by the earth pressure from the natural ground and the embankment behind the backfilling concrete 17, and there is a force that causes them to slide. Further increases resistance to

FIG. 12(a) is a front view of a precast base block 1C according to the third embodiment of the present invention, and (b), (c), (d) and (e) are plan views of the base block 1C; They are a side view, a perspective view and a rear view. In the figure, the same reference numerals are given to the same or corresponding parts as those in FIG. 1, and the description thereof will be omitted.

In the base block 1C according to the third embodiment, the support leg portion 1h extends from the upper end of the standing leg portion 1a, and is separated from the upper end of the standing leg portion 1a by a predetermined distance, as in the base block 1B according to the second embodiment. d2 is not opened. Except for this point, the base block 1C according to the third embodiment has the same configuration as the base block 1B according to the second embodiment, and openings 1i similar to the openings 1g are formed side by side at two locations. , and the convex portion 1d is not formed on the surface in contact with the foundation ground.

Similarly to the foundation block 1B according to the second embodiment, the foundation block 1C according to the third embodiment is also installed on the foundation crushed stone 12 on the ground 11 as shown in FIG. . FIG. 13 is a perspective view looking down obliquely from above during construction of a retaining wall constructed by piling up wall panels 13 in multiple stages on foundation blocks 1C in this foundation. 10 and 12 are denoted by the same reference numerals, and description thereof will be omitted. Moreover, FIG. 14 is sectional drawing of 19 C of retaining walls built by piling up the wall panel 13 on the foundation block 1C. 11 and 13 are denoted by the same reference numerals, and description thereof will be omitted. The retaining wall 19C is constructed with the foundation block 1C as its base, for example, with a 5-minute gradient of 1:0.5 as shown in the figure.

In this retaining wall 19C, a supporting leg portion 1h extends from the upper end of the standing leg portion 1a, and an opening 1i is formed in the supporting leg portion 1h. For this reason, as in the second embodiment, a space connecting the rear of the standing leg 1a and the rear of the wall panel 13 installed at the bottom is formed, and the construction part behind the foundation block 1C and the bottom are installed. The construction portion of the wall panel 13 to be constructed is constructed by placing concrete once and curing it once. However, in some places where the opening 1i does not exist behind the wall panel 13 installed at the lowest stage, the boundary between the lower structure behind the foundation block 1C and the upper structure of the wall panel 13 installed at the lowest stage , is structurally bounded. In addition, the back-filling concrete 17 is formed in a plurality of layers in which the back surface of the wall panel 13 on each stage is successively poured and buried together with the overturn prevention member 14 to a predetermined height, as in the second embodiment. The horizontal joint surface of is formed into a step 17a that is high on the wall panel 13 side and low on the opposite side, and the step 17a extends in the extension direction of the retaining wall 19C.

According to the foundation block 1C according to the third embodiment, the boundary surface is partially formed behind the wall panel 13 installed at the bottom as described above. For this reason, in the base block 1B according to the second embodiment, the support leg 1f extends with a predetermined distance d2 between it and the upper end of the standing leg 1a. The operational effect that the boundary surface is not formed and the displacement is less likely to occur is inferior in the base block 1C according to the third embodiment. However, other than that, the same effect as the foundation block 1B according to the second embodiment is exhibited, and it is possible to provide the precast foundation block 1C capable of suppressing the construction cost of the retaining wall 19C.

In the above-described embodiments and modifications, the case where the foundation blocks 1A, 1B and 1C and 1A1, 1A2 and 1A3 are applied to the foundation structure of the retaining walls 19A, 19B and 19C has been described. It is equally applicable to foundation structures in other structures such as dam walls. Also in that case, the same effects as those of the above-described embodiments and modifications can be obtained.

1A, 1B, 1C, 1A1, 1A2, 1A3... foundation block, 1a... upright part, 1b, 1f, 1h... supporting leg part, 1c, 1g, 1i... opening part, 1d... convex part, 1e... notch part, 2, 4... Embedding nut, 3... Threaded rod (fixing material), 5... Hole (detachable part), 6, 8... Bolt, 7... Connection member, 11... Ground, 12... Crushed stone foundation, 13... Wall panel, 13a Convex part 13b Concave part 14 Overturn prevention member 15 Drawing formwork 16 Back-fill crushed stone 17 Back-fill concrete 17a Step 18 Reinforcing bar 19A, 19B, 19C Retaining wall s1 , s2, s3... Gap

Claims (11)

In a precast foundation block that serves as the foundation of a retaining wall, a wall panel of a size, weight, or thickness that cannot withstand the lateral pressure received from the backfill concrete that is poured behind the panel and moves, is installed above.
An overturn prevention member comprising a standing leg on which the wall panel is installed and a support leg extending in a direction intersecting the standing leg and supporting the standing leg to prevent the wall panel above from falling. A fixing member is provided at a predetermined position of the supporting leg for fixing the first connecting member attached to the wall panel stacked on the upper end of the standing leg and projecting downward from the wall panel. A second connecting member that is pressed against and pushed by the portion projecting upward from the upper end of the standing leg, and the portion protruding upward from the upper end of the standing leg contacts and presses the back surface of the wall panel stacked on the upper end of the standing leg A precast foundation block characterized in that the wall surface to which it is attached is provided on the supporting leg side of the head of the standing leg. 2. The precast foundation block according to claim 1, wherein the fixing member is detachably attached to the support leg. According to claim 1 or 2, the wall panel is engaged with the upright portion so that the lower end is positioned at the upper end of the upright portion or independently connected to the upright portion. Precast foundation block as described. The fixing member is provided on the supporting leg portion behind the standing leg portion from the place where the anti-tipping member is attached to the upper portion of the wall panel installed on the lowest stage. Item 4. A precast foundation block according to any one of Item 3. 5. The support leg according to any one of claims 1 to 4, wherein the support leg extends in a direction intersecting the standing leg from a position spaced apart from the upper end of the standing leg by a predetermined distance. Precast foundation block. 6. The precast foundation block according to any one of claims 1 to 5, wherein the support leg has an opening on a surface facing the foundation ground. 7. The precast foundation block according to any one of claims 1 to 6, wherein the upright portion and the support leg portion have a plurality of protrusions formed on the surfaces thereof in contact with the foundation ground. 8. The precast precast according to any one of claims 1 to 7, wherein the supporting leg has a horizontal notch formed at an end portion away from the standing leg. foundation block. The support legs are constructed with a curved line with a slope, and the inclination of the support legs is wide, starting from a point located below the abutment point between the wall panels installed at the bottom of the retaining wall, and shrinking away from the standing legs. 9. A precast foundation block according to any one of claims 1 to 8, characterized in that it is attached on both sides in the direction. The supporting leg is constructed from a point closer to the standing leg than a point located below the abutting point between the wall panels installed at the bottom of the retaining wall constructed in a curved line with the smallest gradient. Both sides in the width direction are slanted to shrink away from the part, and the attachment/detachment part for positioning the tip of the gap maintaining member at a point below the abutting part between the wall panels installed at the lowest stage. The distance maintaining member is detachably provided at a plurality of locations corresponding to a plurality of slopes of the retaining wall constructed in a curved line with different distances from the upright portion of the both sides of the retaining wall. 9. A precast foundation block according to any one of claims 8 to 10. Cite claim 5 or claim 5 according to the empirical design method that uses prescribed values without performing design calculations for the gradient of retaining walls with a height of 7 m or less, not including the height of the foundation, and the backfill concrete thickness. A retaining wall construction method for constructing a retaining wall using the precast foundation block according to any one of claims 6 to 10.

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