JP2004339898A - Lowermost stage laying block as plinth stone block laid on lowermost stage of large-sized laying block for retaining wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide lowermost stage laying blocks as plinth stone blocks for preventing occurrence of cracks generated on a front wall of the lowermost stage laying blocks of large-sized laying blocks, in particular the large-sized blocks for vegetation used for a cliff or an embankment of a road side part. <P>SOLUTION: The lowermost stage laying blocks 16 comprise: a rectangular front wall 2 inclined rearward of an upper part; a parallelogram vertical counterfort 3 in a reserve direction from right and left ends of a front wall rear face 5; a triangular vertical intermediate wall 8 extending in the reserve direction from a rear face center of the front wall 2 and separating a bottom side from a bottom board 4 to provide a gap 20; and a rectangular bottom board 4 extending in the reserve direction from the lower end of the front wall 2. The lowermost stage laying blocks 16 are laid as the plinth stone blocks on the lowermost stage of the retaining wall by eliminating a counterfort opening from the right and left counterforts 3 and 3, and a bottom board opening from the bottom board 4 respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is used in a prefabricated construction method using a speed earth retaining method, and is a large concrete building block used for retaining wall construction such as a roadside slope or a dike slope previously manufactured in a factory, especially a large-scale planting plant. The present invention relates to a bottom block as a root stone block laid at the bottom of a building block.
[0002]
[Prior art]
The large-sized building block for the retaining wall in the current speed preservation prefabrication method using the large-sized building block in the construction of the retaining wall of the cliff beside the road or the construction of the retaining wall such as a river embankment is shown in FIG. A rectangular front wall 2 having a decorative surface having a width of about 2000 mm and a height of about 1000 mm, and left and right retaining walls 3, 3 extending from the left and right end portions thereof approximately 900 mm vertically in a rearward retaining direction and from the lower end of the front wall. It is formed from a box-shaped large-size building block 1 made of a factory-made rectangular bottom plate 4 having a width of about 2000 mm and a depth of about 900 mm extending in the rear holding direction, and a front wall 2 from a lower level to an upper level of a retaining wall. Are loaded at an angle rearward. Further, the large-sized product block 1 for a retaining wall has a triangular shape with two sides extending from the center 6 of the front wall back surface 5 between the right and left retaining walls 3 and 3 to the front wall back surface 5 and the bottom plate upper surface 7. The bottom slab 4 has an intermediate wall 8 extending in the holding direction, and the bottom slab 4 has a bottom slab opening 9 in order to ensure backfilling of the embankment and the workability and filling of the embankment concrete. The left and right retaining walls 3, 3 also have similar retaining wall openings 10, and are opened at the lower portions of the left and right decorative surfaces of the front wall 2 by communicating with drain holes 12, 12, respectively, from the back. (Patent Document 1).
When the retaining wall is used, a large-sized planting block 21 for planting is required on the front side of the retaining wall in consideration of the natural environment. As shown in FIG. At 31, the upper side is separated and protrudes forward, and a plant is planted in the rear portion of the front wall rear surface 25 to take into account the landscape. The large planting block for planting 21 for planting in this manner has a short back wall 29 that connects the rear ends of the left and right retaining walls 23 and the rear end of the intermediate wall 26 and holds soil for planting. Further, a bottom plate opening 27 is provided in the bottom plate 24, a retaining wall opening 28 is provided in the left and right retaining walls 23, and a drain hole 30 is opened in the front wall 22 from the inside. In such a large-sized planting block 21 for planting, since the soil for planting is put in the block between the front wall rear surface 25 and the rear wall 29, the entire planting large-sized building block 21 takes weight. It will be.
[0003]
As shown in FIG. 7, a general method of loading these large-sized building blocks 1 for retaining walls is not to directly load the large-sized building blocks 1 on the ground, but to hit the foundation concrete 13 on the ground. An appropriate number of hard plastic set plates 14 are superposed and placed below the four corners of the lower surface of the lowermost large-sized building block 1 at which the four corners are in contact with each other to adjust the height to a uniform horizontal plane. A mortar 15 is laid on the foundation concrete 10 between the adjacent set plates 14 and 14 according to the height, and the lowermost large-sized building block 1 is placed on the mortar 15.
[0004]
By the way, after the lowermost large-sized building block 1 is laid as described above, the heavy-weight planting large-sized building block 21 is particularly loaded on the retaining wall formed by sequentially loading the upper-stage large-sized building blocks. In the retaining wall, since the lowermost block 16 as a root stone block installed at the lowermost stage of the large planting block 21 is heavily weighted from above, the upper end 17 of the front wall of the lowermost block 16, particularly It has been found that a crack 18 may be generated downward from the front surface of the upper end of the central portion.
[0005]
[Patent Document 1]
JP-A-11-29945 [0006]
[Problems to be solved by the invention]
The problem to be solved by the present invention is a large-sized building block used for a retaining wall of a cliff on the side of a road such as a highway or a retaining wall of a river embankment. An object of the present invention is to provide a lowermost block as a root stone block which prevents cracks from being generated on a front wall of a large pile block as a root stone block piled on a floor.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the inventors have developed a large-sized building block for retaining walls, particularly a structure of a bottom-level building block stacked as a stone block at the bottom of a large-sized building block for planting, using a mortar or a lower mortar. In order to consider the influence of unevenness and accuracy, the following measures were taken to conduct experiments. That is, it is distributed to the left and right from the center of the width of the lowermost block, laid mortar is used instead of mortar, a set plate is placed in contact with the four corners on the lower surface of the lowermost block, and the center of the front wall of the lowermost block is further placed. Attach a strain gauge to the upper end and apply the load pressure of the retaining wall consisting of a large building block applied from above. An experiment was conducted on the relationship with the crack entering the lower block.
[0008]
As shown in FIG. 9, the test piece of the lowermost stack block in this experiment is (a) or (a) of the lowermost stack block having an intermediate wall in which the bottom wall and the bottom are in contact with each other without the retaining wall opening and the bottom plate opening. '), (B) or (b') of the lowermost building block in which the retaining wall opening and the bottom plate opening are eliminated and the intermediate wall is eliminated, and the intermediate wall where the retaining wall opening and the bottom plate opening and the bottom plate and the bottom contact. (C) or (c ′) of the current lowest-stage product block having the following formulas was used as the lowest-stage product block.
[0009]
The experiment consisted of an experiment (1) in which the width of the spread sand was 500 mm, and an experiment (2) in which the width of the spread sand was 2000 mm.
[0010]
In the block having the intermediate wall without the retaining wall opening and the bottom plate opening in the experiment (a) in which the spread sand of 500 mm in (1) was used, the crack 18 had a load of 290 kN, a breaking load of 500 kN or more, and a crack width of 1.2 mm. The center of the crack 18 almost reached the lower side of the block, and the crack 18 branched right and left on the way.
[0011]
In the block (b) in which the retaining wall opening and the bottom plate opening were eliminated and the intermediate wall was also eliminated, no crack 18 was generated at a load of 500 kN and a breaking load of 500 kN.
[0012]
In the current lowermost block of (c), one crack 18 which reaches the lower side substantially at the center was entered at a load of 142 kN and a breaking load of 300 kN or more.
[0013]
In the block (2 ') of experiment (a') in which the spreading sand was set to 2000 mm, the block having the intermediate wall without opening of the retaining wall and bottom plate had a load of 180 kN, a breaking load of 500 kN or more, and a crack width of 1.5 mm. The center of the crack 18 was almost ／ of the vertical length, and the crack 18 branched right and left on the way to reach the lower side.
[0014]
In the block (b ′) in which the retaining wall opening and the bottom plate opening were eliminated and the intermediate wall was eliminated, no crack 18 was generated at 500 kN load and 500 kN breaking load as in (b).
[0015]
In the current lowermost block of (c ′), a plurality of cracks 18 were entered at the center and left and right at a load of 250 kN and a breaking load of 467 kN or more.
[0016]
As a result of the above experiment, it was found that there was a large difference in load resistance depending on the presence or absence of the intermediate wall. Therefore, it is preferable that the root stone block at the bottom has no intermediate wall. As described above, without the intermediate wall, it was found that cracks did not occur even when a load 1.7 times or more the target load was applied.
[0017]
On the other hand, in the current large-sized building block, as shown in FIG. 8, the contact surface 19 of the lowermost-stage building block 16 with respect to the upper-stage building block stacked on the lowermost-stage building block 16 placed on the lowermost stage is The upper surface of the front wall 2 and the upper surface of the retaining wall 3 indicated by oblique lines at the upper end of the lowermost block. By the way, the vertical load transmitted from the upper block to the lowermost block 16 is larger on the rear side than on the front side of the lowermost block 16 as a result of the retaining wall leaning on the rear side due to the inclination. Therefore, most of the vertical load is supported by the retaining wall 3, and the transmission of the vertical load is efficiently performed by the retaining wall 3.
[0018]
By the way, the inventors of the present invention have studied various causes of cracks 18 entering from the upper end of the front wall of the lowermost building block 16 of the current large-sized building block 1. (1) The hardness of the set plate 14 is low, and When a material having a large amount of compressive deformation is used, or (2) there is a difference in the smoothness of spread of the spread mortar 15 and the center is higher than both ends, and (3) the spread mortar 15 When the contact of the lowermost stacking block 15 is distributed to the left and right from the center of the lowermost stacking block 16 and certain conditions such as a case where the total width is about 500 to 1000 mm overlap with the upper end 17 of the front wall of the lowermost stacking block 16 It was found from the above experiment that cracks 18 were generated.
[0019]
Therefore, the inventors further studied the following points.
(1) Installation Position of Set Plate with respect to Lowermost Stack Block 16 The set plate 14 is generally installed immediately below the retaining wall 3 of the lowermost stack block 16.
[0020]
(2) Immediately after installation of the lowermost stack block 16 Immediately after installation of the lowermost stack block 16, it is considered that the amount of compressive deformation of the set plate 14 has not yet occurred much.
[0021]
(3) Deformation due to Compression of Set Plate 14 It is considered that the maximum vertical force starts to act after construction after all the large product blocks have been installed on the upper stage, and the compression deformation of the set plate 14 also starts to become maximum.
[0022]
(4) Since the bottom slab 4 of the lowest block 16 of the structural model assumed after the deformation of the set plate 14 is supported by the mortar 15, it is considered that the bottom plate 4 is supported by a ground spring. Considering the deformation of the set plate 14 due to the compression of the above (3), it is considered that a large vertical force is acting immediately below the retaining wall 3 of the lowermost stack block 16.
[0023]
(5) Displacement and Deflection of Lowermost Stack Block Considering the structural model assumed after the deformation of the set plate 14 in (4) above, the displacement and deflection of the lowermost stack block 16 are large at the end thereof. The central part is considered small.
[0024]
Based on the above idea, the cause of the crack 18 at the upper end portion 17 of the front wall of the lowermost block 16 was simulated by computer analysis and examined. The following results were obtained.
[0025]
a. The stress concentration at the upper end portion 17 of the front wall of the lowermost stack block 16 is caused by the shape of the lowermost stack block 16, and the intermediate wall 8 is a support member required to resist the vertical load from the upper stack block. It is. However, it is considered that the presence of the intermediate wall 8 causes a stress concentration at the upper end 17 of the front wall at the same time.
[0026]
b. It is considered that the retaining wall opening 10 of the retaining wall 3 and the bottom plate opening 9 of the bottom wall 4 cause stress concentration due to their presence.
[0027]
c. Unless the elastic bearing takes into account the ground spring (due to the upward drag of the ground), it is considered that no stress concentration occurs on the upper end 17 of the front wall of the lowermost block 16.
[0028]
Therefore, based on the above results, the shape of the large-sized building block laid as a root stone block at the bottom was reviewed and obtained. The bottom-stage building block 16 of the present invention reduces the occurrence of cracks 18 from the center of the upper end 17 of the front wall. It is a new structure with suppressed.
[0029]
In view of the above, the means of the present invention for solving the above-mentioned problems are, in the invention of claim 1, a rectangular front wall 22 in which the upper part is inclined forward and the rear upper part is a planting part 32; A vertical retaining wall 23 extending in the retaining direction from the left and right ends via the joining wall 31 respectively, and retreating upward to form a parallelogram, and a rectangular bottom plate extending in the retaining direction from the lower end of the front wall 22. 24, a rear wall 29 connecting the lower portions of the left and right retaining walls 23, and a vertical intermediate wall 26 parallel to the retaining wall 23 from the center of the front wall rear surface 25 and having a bottom connected to the bottom plate 24 and a rear connected to the rear wall 29. In the large-sized building block 1 for a retaining wall having left and right parallelogram-shaped retaining walls 23 in the retaining wall 23 and a bottom plate opening 28 in the bottom slab 24, a large-sized block laid at the lowest level of the retaining wall. Planting the block as the lowest block 16 of the root stone block 32, a front wall 3 having an upper portion inclined rearward, a joining wall 31 and a retaining wall opening 27, and a parallelogram-shaped retaining wall 3 extending in a retaining direction from right and left ends of the front wall 2; A large-sized product for a retaining wall, comprising a bottom plate 4 having no plate 29 and only a plate body, and an intermediate wall 8 having a lower portion as a lower side and being separated from the bottom plate 4, and having no rear wall 29. This is a bottom block 16 for a root stone block laid at the bottom of the block.
[0030]
According to the second aspect of the present invention, the intermediate wall 8 has a hanging hole 11 for lifting, and the lowermost stack as a root stone block laid at the lowermost level of the large-size building block for retaining wall according to the means of the first aspect. Block 16.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIGS. 1A and 1B show a lowermost building block 16 laid as a root stone block at the lowermost stage of a large-sized building block according to the present invention. FIG. 1A is a perspective view of the front wall 2 as viewed from the front side, and FIG. FIG. 2 is a perspective view of the device viewed from the rear side. FIG. 2 is a front view of the lowermost product block 16 of the present invention. FIG. 3 is a side view of the lowermost product block 16 of the present invention. FIG. 4A is a cross-sectional view taken along the line AA of FIG. 2, and FIG. 4B is a cross-sectional view taken along the line BB of FIG. 2. FIG. 5A is a perspective view of a large planting block for planting 21 having a planting portion on the front surface to be loaded on the lowermost building block 16 of the present invention, and FIG. (B) is the perspective view which looked at the front wall 22 from the back side.
[0032]
One embodiment of the lowermost product block 16 of the present invention will be described with reference to the perspective views (a) and (b) of FIG. The lowermost building block 16 is installed as a root stone block at the bottom of the large-sized building block 1 which is loaded as a retaining wall on the slope of a cliff or a levee beside a road, particularly a large-sized building block 21 for planting. The upper part of the lower building block 16 consists of the front wall 2 having a horizontally long rectangular shape having a length of 1000 mm and a width of 2000 mm, which is receded backward and inclined in accordance with the slope of the cliff or embankment to be installed. . Since the front wall 2 has a symmetrical decorative board on the front surface and is installed at the lowermost stage as a root stone block, the drainage hole 30 that the large planting block 21 for planting loaded on the upper stage has in the front wall 22 has: It is not provided in the lowermost stack block 16. However, in places where there is a large amount of water, the drain holes 12 may be provided as necessary.
[0033]
At the left and right ends of the front wall rear surface 5 of the front wall 2 of the lowermost block 16, right and left parallelogram-shaped vertical retaining walls 3, 3 extending in the retaining direction are provided. On the other hand, there is provided a vertical intermediate wall 8 having a triangular shape having a lower portion as a base in the lower direction from the center 6 of the lateral width of the front wall rear surface 5 and a vertex at the center 6 of the upper front wall rear surface 5. Further, a rectangular bottom plate 4 extends from the lower end of the front wall 2 in the holding direction. It is assumed that the right and left vertical parallelograms 3 and 3 are made of simple wall slabs without providing the stencil wall openings 27 and the bottom slab 4 with the bottom slab openings 28. Further, a lower side of the vertical intermediate wall 8 having a triangular shape is provided with a gap 20 apart from the bottom plate 4.
[0034]
Further, a suspending hole 11 through which a wire for lifting the lowermost stack block 16 by a crane at the time of construction is opened in the triangular vertical intermediate wall 8.
[0035]
In the construction of the retaining wall of the cliff on the road side or the construction of the retaining wall such as the embankment of the river by the large-sized building block 1, particularly the large-sized building block 21 for planting, the lowermost building block 16 of the present invention is held as a root stone block. The following results were obtained by using it to lay at the bottom of the wall.
[0036]
(1) Without setting the mortar 15 on the foundation concrete 13, as shown in FIG. 7, only the set plates 14 arranged at the four corners support the four corners of the lowermost block 16 which is the root stone block of the present invention. In this case, the load due to the loading of the retaining wall composed of the large-sized building block 1 that greatly exceeds the load assumed in the stability calculation, for example, the large-sized building block 21 for planting, is applied. No crack 18 was found in the center of the front wall 2 of the portion 17.
[0037]
(2) If the leveling of the mortar 15 is uniform, even if the load of the retaining wall by the large planting block for planting 21 greatly exceeds the load assumed in the stability calculation, even if the load of the retaining wall is loaded, No crack 18 was found in the center of the front surface 2 of the upper end portion 17 of the wall.
[0038]
(3) When the level of the mortar 15 is insufficient and the center of the mortar 15 rises up, and the supporting state of the lowermost stack block 16 is lowered at both left and right ends, and becomes a state like a balance, the upper end of the front wall. The crack 18 generated in the center of the front wall 2 of 17 may be generated at a load level assumed in the stability calculation. For example, when the width of the lowermost block is 2000 mm and the width of the raised portion at the center of the mortar 15 is in the range of 500 mm to 1000 mm, the crack 18 is particularly likely to occur. If the uniform installation surface of the mortar 15 is in the range of 1000 mm or more, preferably 1500 mm or more, even if the retaining wall of the large-sized building block 1 having a load greatly exceeding the load assumed in the stability calculation is loaded, No crack 18 was found in the center of the upper end 17 of the front wall of the block 16.
[0039]
【The invention's effect】
As described above, the lowermost building block laid at the bottom of large-sized building blocks, especially large-sized planting blocks for planting, to be used as retaining walls on the slopes on the road side or on the slopes of river embankments In the large stacking block to be stacked on the upper stage, the left and right retaining walls have openings in the left and right siding walls and the bottom plate opening in the bottom slab, as in the conventional large-sized blocks, whereas the lowermost stacking block of the present invention has the left and right retaining walls. The bottom plate has no opening, and the lower side of the triangular vertical intermediate wall extending from the center of the back of the front wall of the lowermost block is spaced apart from the bottom plate to provide a gap, and a hanging hole is opened in this vertical intermediate wall. Specializing in the root stone block to be laid at the bottom of a large-sized building block, and generated from the center of the upper end of the front wall of the bottom-layer building block during laying, especially after laying. Doing Cracks can be eliminated, greatly increase the strength, etc. it becomes beautifully visually lowermost product block of the present invention is intended to achieve the ineffective in the prior art.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lowermost stack block of the present invention, in which (a) is a perspective view of a front wall viewed from the front side, and (b) is a perspective view of a front wall viewed from the back side.
FIG. 2 is a front view of the lowermost product block of the present invention.
FIG. 3 is a side view of the lowermost product block of the present invention.
4 is a view of the lowermost product block of the present invention as viewed from the direction of the arrow shown in FIG. 2; FIG. 4 (a) is a view taken along the line AA of FIG. 2; It is an arrow view of cutting.
FIG. 5A is a perspective view of a large-sized planting block having a planting portion on a front surface for loading on the lowermost stacking block of the present invention, in which FIG. () Is a perspective view of the front wall as viewed from the rear side.
FIG. 6 is a perspective view of a conventional large-sized building block including a bottom-level building block, in which (a) is a perspective view of a front wall viewed from a front side, and (b) is a perspective view of a front wall viewed from a back side.
FIG. 7 is an explanatory view of a state of installation of a lowermost stack block of a conventional large stack block.
FIG. 8 is a diagram illustrating a contact surface of the large-sized product block with the lower-level product block and the upper-level block.
FIG. 9 is a diagram showing a difference in the occurrence of cracks between the presence or absence of the retaining wall opening and the bottom wall opening and the presence or absence of the intermediate wall of the lowermost building block of the large-sized building block.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Large-sized building block 2 Front wall 3 Holding wall 4 Bottom plate 5 Front wall back surface 6 Center 7 Bottom wall upper surface 8 Intermediate wall 9 Bottom plate opening 10 Holding wall opening 11 Hanging hole 12 Drainage hole 13 Foundation concrete 14 Set plate 15 Mortar 16 Lowermost Stack block 17 Front wall upper end portion 18 Crack 19 Contact surface 20 Gap 21 Large planting block for planting 22 Front wall 23 Stay wall 24 Bottom plate 25 Front wall back surface 26 Intermediate wall 27 Stay wall opening 28 Bottom plate opening 29 Back wall 30 Drain hole 31 Joint wall 32 Planting part

Claims (2)

A rectangular front wall with the upper part tilted forward and the rear upper part as a planting part, and the left and right ends of the front wall extend in the restraining direction through the joining walls, respectively, and the upper part recedes backward to form a parallelogram vertical Siding wall, a rectangular bottom plate extending in the holding direction from the lower end of the front wall, a back wall connecting the lower portions of the left and right holding walls, and a bottom portion parallel to the holding wall from the center of the back of the front wall, with the bottom being a bottom plate. A vertical intermediate wall connected to the back wall, a left and right parallelogram-shaped retaining wall has a retaining wall opening, and a bottom plate has a bottom plate opening. The large-sized building block to be laid on the bottom is the bottom block of the root stone block. A vertical parallelogram-shaped retaining wall and a bottom plate opening are eliminated to use only a plate. A lithologic block laid at the bottom of a large-sized building block for retaining walls, which is formed from a slab and an intermediate wall with the lower side being the lower side and separated from the bottom slab, and having no back wall. Lower stack block. The lowermost stacked block as a root stone block laid on the lowermost stage of the large-sized building block for retaining wall according to claim 1, wherein the intermediate wall has a hanging hole for lifting.

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