JP2004270348A - Concrete block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete block having not only stability but also sufficient structural strength and making a large improvement in economic efficiency. <P>SOLUTION: This concrete block is composed of one body 3 and four legs 2 connected two by two to both ends. The concrete block is constituted such that the phase of an axis 4 of each leg 2 centering on an axis 5 of the body 3 is different by 90° from the axis 4 of the leg 2 positioned on the opposite side, and designed such that the ratio of an area S representing the space of the blocks, to the maximum value K<SP>2</SP>of the vertical sectional area of the leg 2 is in a range of 1.0-1.8, that the inclination angle of the axis 4 of the leg 2 to the axis 5 of the body 3 is in a range of 45-90° and that the inclination angle of the outer peripheral surface of the leg 2 to the axis 4 of the leg 2 is in a range of 2-30°. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２０】
この関係式のうち、左辺の分数の分母は、脚部２の垂直断面積（軸線４と直交する断面の面積）の最大値を意味し、分子は、図４に示した矩形（Ｓ）の面積を意味している。尚、この矩形（Ｓ）は、複数のコンクリートブロック１間において良好なかみ合わせを得るために必要となる、ブロック間スペースを代表する面積である。
【００２１】
ここで、「ブロック間スペースを代表する面積」について説明する。例えば、複数のコンクリートブロック１を並べ、層で積む場合、図５に示すように、二つの隣接するコンクリートブロック１，１の間に形成されるスペースＳａに、他のコンクリートブロック１の脚部２を順次係合させていく、というような工程が実施されるが、このとき、スペースＳａが一定の面積よりも小さい場合には、スペースＳａに、脚部２を進入させることができなくってしまう。
【００２２】
つまり、ブロック間スペースＳａに他のコンクリートブロック１の脚部２を進入させ、係合させることによって、コンクリートブロック１間において良好なかみ合わせを得るためには、形成されるスペースＳａが、脚部２の垂直断面積との関係で、一定の面積よりも大きいことが必要となる。ここに言う「一定の面積」を代表したものが、ブロック間スペースを代表する面積である。
【００２３】
ブロック間スペースを代表する面積Ｓは、上記数式に示したように、（Ｍ＋２Ｌｃｏｓα）Ｌｓｉｎαとして計算することができる。つまり、代表する面積Ｓは、図４に示すように、一辺がＭ＋２Ｌｃｏｓα、もう一つの辺がＬｓｉｎαである矩形の面積で代表されると考えることができる。
【００２４】
尚、胴部３の軸線５の長さ「Ｍ」に加算される「２Ｌｃｏｓα」は、図３に示した脚部２ａの軸線４ａの平行突出量（胴部３の軸線５方向への突出量）である「Ｌｃｏｓα」と、脚部２ｃ，２ｄの軸線４ｃ，４ｄの平行突出量「Ｌｃｏｓα」の和である。また、「Ｌｓｉｎα」は、脚部２ｃ，２ｄの軸線４ｃ，４ｄの垂直突出量（胴部３の軸線５と直交する方向への突出量）を意味する（図４参照）。
【００２５】
また、ブロック間スペースを代表する面積Ｓは、相対脚長「Ｌｓｉｎα／Ｋ」（脚部２の垂直突出量と、脚部２の幅寸法の最大値との比）と、相対脚間距離「（Ｍ＋２Ｌｃｏｓα）／Ｋ」との積として計算することもできる。
【００２６】
上記関係式は、「左辺が１．０以上であること」を意味しているので、左辺の分数の分子が分母と同じか、それよりも大きいこと、つまり、代表する面積Ｓが、脚部２の垂直断面積の最大値Ｋ^２以上であることを規定するものである。従って、この関係式が成り立つような範囲で、軸線４の長さ、その傾斜角度、軸線５の長さ、及び、脚部２の幅寸法の最大値を設定すれば、良好なかみ合わせ状態を得られるコンクリートブロック１を設計することができる。
【００２７】
尚、脚部２の軸線４の長さ「Ｌ」を極端に短く設定した場合であっても、その分、胴部３の軸線５の長さ「Ｍ」を長くすることによって、上記関係式を満たすようなブロックを設計できることになるが、脚部２の軸線４が短すぎると、空隙への脚部の進入が僅かになり、良好なかみ合わせ状態を得ることができなくなってしまう。
【００２８】
従って、上記関係式を満たすとともに、脚部２の軸線４の長さ「Ｌ」と脚部２の幅寸法の最大値「Ｋ」の比（「Ｋ」を１とした場合の「Ｌ」の割合）を０．８５以上に設定して設計することが好適である。
【００２９】
一方、構造強度については、脚部２及び胴部３が短く、また、脚部２の断面幅が大きい方が有利である。つまり、胴部３や脚部２が長すぎると、構造強度が小さくなり、鉄筋による補強が必要となる。従って、空隙のサイズを代表する胴部と脚部から構成される面積と、脚部の大きさを代表する脚部最大幅の２乗の比を適切な範囲にする必要がある。そこで、本実施形態のコンクリートブロック１は、下記の関係式が成り立つように設計されている。
【００３０】
【数２】

【００３１】
この関係式は、「左辺が１．８以下であること」、つまり、代表する面積Ｓが、脚部２の垂直断面積の最大値Ｋ^２の１．８倍以下であることを規定するものである。数値解析結果より、この数値が１．８を超えると、構造強度上問題があること、また、１．８以下であれば、鉄筋による補強を行わなくても、十分な構造強度が得られることを見出した。
【００３２】
尚、胴部３の軸線５の長さ「Ｍ」を極端に長く設定した場合であっても、その分、脚部２の軸線４の長さ「Ｌ」を短くすることによって、上記関係式を満たすようなブロックを設計できることになるが、脚部２の軸線４、及び、胴部３の軸線５のいずれか一方でも長すぎると、無筋で十分な構造強度を確保することができなくなってしまう。
【００３３】
従って、上記関係式（数２）を満たすとともに、胴部３の軸線５の長さ「Ｍ」と脚部２の幅寸法の最大値「Ｋ」の比（「Ｋ」を１とした場合の「Ｍ」の割合）を０．９以下に設定して設計することが好適である。
【００３４】
本実施形態に係るコンクリートブロック１は、上記の二つの関係式（数１、数２）をいずれをも満たす範囲で設計されている。つまり、ブロック間スペースを代表する面積Ｓと脚部２の垂直断面積の最大値Ｋ^２との比が、１．０〜１．８の範囲となるように設計されている。このため、安定性を有するだけでなく、安定性と相反する関係にある構造強度についても、優れた性能を有するブロックとすることができる。尚、ＳとＫ^２との比は、１．１〜１．７の範囲となるように設計することが更に好適である。
【００３５】
尚、脚部２の軸線４ａ〜４ｄの傾斜角度αは、本実施形態においては６６°に設定されている。但し、必ずしもこの角度には限定されず、４５°〜９０°の範囲内で任意に設定することができる。下限を４５°としたのは、傾斜角度αがこれより小さいと、かみ合わせの効果が小さくなってしまうからであり、また、上限を９０°としたのは、これより大きいと、ブロック間スペースを代表する面積Ｓを狭めることになり、脚部２をかみ合わせることが困難となってしまうからである。
【００３６】
また、図３からも分かるように、このコンクリートブロック１の脚部２（例えば、脚部２ｃ）は、軸線４（４ｃ）に対し、外周面が傾斜しており（図３において、補助線４ｃ’は、軸線４ｃと平行な線であり、角度βは、軸線４ｃに対する脚部２ｃの外周面の傾斜角度を表している。）、胴部３に近い基端部から先端にかけて、次第に幅（断面積）が小さくなっていく、つまり、「先細り」の形状となっている。先細りの形状となっていた方が、据え付け作業の際、脚部２をブロック間スペースへ、円滑に、かつ、容易に進入させることができるからである。
【００３７】
本実施形態においては、この脚部２の外周面の傾斜角度βは、６°に設定されている。但し、必ずしもこの角度には限定されず、２°〜３０°の範囲内で任意に設定することができる。尚、下限を２°としたのは、これより小さいと、据え付け作業の円滑化、容易化という効果はそれ程期待することができず、一方、上限を３０°としたのは、これより大きいと、脚部２がわずかしか進入できず、かみ合わせの効果が減少してしまうことになるからである。
【００３８】
尚、本実施形態においては、脚部２は、断面が多角形となる形状をしているが、断面が円形、或いは、楕円形となるように構成することもできる。特に、多角形とすると、軸線寸法等が同一であっても、円形等に比べて空隙率が大きくなり、経済性が更に向上する。また、脚部２の先端面は、図１に示すように、コンクリートブロック１の天端面６（地面Ｇ上に載置した場合に、地面Ｇには接しない脚部２の先端面）が地面Ｇと平行となるように角度設定されている。但し、必ずしもこのような角度に設定されなくても良い。
【００３９】
また、前述したように、本実施形態においては、脚部２ａ〜２ｄの形状はいずれも同一であるが、第一組（脚部２ａ，２ｂ）の形状と第二組（脚部２ｃ，２ｄ）の形状が異なるように構成することもできる。この場合の上記関係式（数１、数２）における「Ｋ」の値（脚部２の幅寸法の最大値）は、最も小さい脚部２についての値を採用し、また、「Ｌ」及び「α」の値は、その脚部２以外の脚部２についての値を採用する。
【００４０】
図６は、本実施形態のコンクリートブロック１を層で積んで構築した堤体の被覆工８の俯瞰図であり、図７は、その堤体の被覆工８を側方から見た状態を示す図である。これらの図からも分かるように、各コンクリートブロック１の四つの脚部２のうち、下を向いている脚部２を、そのコンクリートブロック１の前方（斜面下側）に位置するコンクリートブロック１のブロック間スペースに進入させ、横向きの脚部２の上に係合させることができ、並べられたコンクリートブロック１の全体を「かみ合った状態」とすることができる。従って、非常に安定した堤体を構築することができる。
【００４１】
また、第２層を構成するコンクリートブロック１を、第１層のコンクリートブロック１の上に完全に載置させるのではなく、半分だけ載置させ、残りの半分は、第１層のコンクリートブロック１の接地面と同一面上に載置させることができるので、図示されているように２層被覆に適用した場合、層厚を小さくすることができる。従って、使用するコンクリートの量を大いに節減することができ、非常に経済的である。
【００４２】
【実施例】
ここで、本発明に係るコンクリートブロックの実施例を説明する。まず、本発明に係るコンクリートブロックとして３種類のブロック模型（Ａ１〜Ａ３）を用意し、更に、比較例として４種類のブロック模型（Ｂ１〜Ｂ４）を用意した。
【００４３】
そして、これらのブロック模型を積んで堤体のモデルを作り、それぞれについて水理模型実験を行って、ＫＤ値を測定し、安定性を比較した。その結果を「表１」に示す。
【００４４】
【表１】

尚、上記表の第２欄「ブロック間スペースを代表する面積と、脚部の断面積の最大値の比」は、前述の二つの関係式における左辺の値（即ち、（Ｍ＋２Ｌｃｏｓα）Ｌｓｉｎα／Ｋ^２）の値である。
【００４５】
一般的な四脚ブロックのＫＤ値が８．３であることを考慮すると、この実験結果より、「ブロック間スペースを代表する面積と、脚部の断面積の最大値の比」が１．０よりも大きいブロックＡ１〜Ａ３（本発明）は、いずれも安定性に優れていることが判る。一方、１．０よりも小さいブロックＢ１（比較例）は、用意したブロックの中で最も安定性が低いということが確認された。
【００４６】
次に、上記ブロックＡ１〜Ａ３、及び、Ｂ１〜Ｂ４について、数値解析により、発生する応力度を比較した。その結果を「表２」に示す。
【００４７】
【表２】

尚、上記表における「応力度比」は、一般的な無筋の四脚ブロックに発生する応力度を「１」とした場合の比を意味し、値が小さいほど、「構造強度は大きい」ということになる。
【００４８】
この実験結果より、「ブロック間スペースを代表する面積と、脚部の断面積の最大値の比」が１．８以下であるブロックＡ１〜Ａ３（本発明）は、いずれも十分な構造強度を有していることが判る。一方、１．８よりも大きいブロックＢ２〜Ｂ４（比較例）は、かなり構造強度が劣っており、鉄筋等による補強が必要となることが確認された。
【００４９】
【発明の効果】
以上に説明したように、本発明に係るコンクリートブロックは、非常に安定性が良く、具体的には、一般的な四脚ブロックの７割程度以下の質量で、十分な安定性を確保することができる。また、安定性と相反する関係にある「構造強度」についても、優れた性能を有し、鉄筋による補強を行わなくても、十分な構造強度のブロックとすることができる。
【００５０】
従って、ブロック断面を小さくすることができ、使用するコンクリートの量を節減することができる。また、小型の重機による施工が可能となるため、材料費だけでなく、工費の面でも、経済性が向上する。
【００５１】
更に、層被覆を対象にした場合、層厚を小さくすることができるため、全断面被覆の場合に比べて、より一層コンクリート使用量を節減できる。従って、本発明に係るコンクリートブロックを使用した場合、経済性を飛躍的に向上させることができる。
【図面の簡単な説明】
【図１】本発明に係るコンクリートブロック１を斜め側方から見た状態を示す図。
【図２】図１に示したコンクリートブロック１の正面図。
【図３】図１に示したコンクリートブロック１の脚部２の軸線４ａ〜４ｄ及び胴部３の軸線５を示す図。
【図４】図１に示したコンクリートブロック１のブロック間スペースを代表する面積Ｓの説明図。
【図５】コンクリートブロック１，１間に形成されるスペースＳａの説明図。
【図６】図１に示したコンクリートブロック１を２層に積んで構築した堤体被覆工８の俯瞰図。
【図７】図６の被覆工８を側方から見た状態を示す図。
【符号の説明】
１：コンクリートブロック、
２：脚部、
３：胴部、
４：脚部の軸線、
５：胴部の軸線、
６：天端面、
７：ハンチ、
８：堤体の被覆工[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a concrete block used for wave breaking work, covering work, shoring work, and the like in a port, fishing port, coast, river, or the like.
[0002]
[Prior art]
The wave-dissipating block has (1) sufficient stability against wave force, etc., and (2) sufficient structural strength against external force (wave force, collision, etc.) and the weight of the block. (3) It is required that a proper porosity can be obtained when stacked so that the energy of waves can be reduced.
[0003]
[Problems to be solved by the invention]
Wave-dissipating blocks that have good mutual engagement when stacked are generally highly stable. For example, a wave-dissipating block as shown in FIG. 1 of Patent Document 1 has a stable constant (KD) of 20 or more according to the Hudson equation, and has extremely high stability. However, since the diameter of each part is small and the structural strength is not so large, it is often reinforced by a reinforcing bar or the like.
[0004]
[Patent Document 1]
JP-B-51-18730 (FIG. 1)
[0005]
On the other hand, the block having the highest structural strength is a square block, but cannot be engaged and has low stability.
[0006]
When it is necessary to stack wave-dissipating blocks in layers, if the layer thickness can be reduced (thinned) as much as possible, the amount of concrete used to manufacture the blocks can be reduced, and as a result, economic efficiency can be improved. However, in the conventional block, when the layer thickness is increased, or when the layer thickness is reduced, there is a problem that the engagement hardly occurs and the stability cannot be secured.
[0007]
The present invention has been made in order to solve the above problems, and provides a concrete block which not only has stability but also has sufficient structural strength and can dramatically improve economic efficiency. The purpose is to do.
[0008]
[Means for Solving the Problems]
The concrete block of the present invention is constituted by one body located at the center and a total of four legs each connected to two ends of the body, two legs on one side of the body. Are in a twisted position with respect to the axis of the other leg, the length of the axis of the leg is L, the inclination angle is α, the length of the axis of the trunk is M, and the width of the leg is If the maximum value of the dimension was K, (M + 2Lcosα) value of Lsinα / ^{K 2} is in the range of 1.0 to 1.8, the inclination angle of the axis of the leg portion relative to the axis of the barrel portion of 45 to 90 ° And the inclination angle of the outer peripheral surface of the leg with respect to the axis of the leg is designed to be in the range of 2 to 30 °. The “leg axis” is an imaginary line passing through the center of the tip surface of the leg portion, and means a line orthogonal to the tip surface.
[0009]
The cross-sectional shapes of the legs and the trunk may be polygonal, but not limited thereto, and may be circular (including elliptical).
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. The concrete block 1 according to the present invention is integrally formed of concrete, and basically has four legs 2 (2a to 2d) and one leg as shown in FIG. It is constituted by the body 3.
[0011]
The body 3 is located at the center of the concrete block 1, and each of the legs 2 a to 2 d is connected to two ends of the body 3. In other words, the leg 2 is divided into a first set of the leg 2a and the leg 2b adjacent thereto, and a second set of the leg 2c and the leg 2d adjacent thereto. One set and the second set are configured to be connected by the body 3. The shape of each of the legs 2a to 2d is the same.
[0012]
Here, the projecting directions of the legs 2a to 2d will be described. The axes of the first pair of legs 2a and 2b are in a relationship that they exist on one virtual plane passing through the axis of the trunk 3 (here, this virtual plane is referred to as "F1"). Also, the axes of the second pair of legs 2c and 2d are also on a single virtual plane passing through the axis of the body 3 (here, this virtual plane is referred to as "F2"). .
[0013]
However, the virtual planes F1 and F2 are orthogonal to each other on the axis of the body 3. The axes of the first set of legs 2a and 2b are located at "twisted positions" with the axes of the second set of legs 2c and 2d, respectively.
[0014]
When one leg 2 faces upward (for example, leg 2a in FIG. 2), another leg 2 adjacent thereto (leg 2b in FIG. 2) faces downward. It is configured to face. In this case, two legs 2, 2 (the legs 2c, 2d in FIG. 2) located on the opposite side (the opposite side across the body 3) from the legs 2 facing in the vertical direction. Will face sideways.
[0015]
Further, in the present embodiment, in order to improve the structural strength, an appropriate haunch 7 is provided at a joint between the trunk 3 and the leg 2.
[0016]
FIG. 3 is a view showing axes 4a to 4d of the legs 2 of the concrete block 1 of FIG. In the concrete block 1, in order to secure the stability, it is desired that a good engagement state is obtained between the blocks. In order to obtain good engagement, it is necessary to lengthen the leg 2, reduce the sectional width, and set the length of the trunk to an appropriate length.
[0017]
That is, the stability is improved by allowing the leg 2 to enter the gap formed by the trunk 3 and the leg 2 and ensuring the engagement, but if the gap is narrow, the leg cannot be sufficiently entered. . Therefore, the ratio of the square of the maximum width of the leg 2 representing the size of the leg 2 to the area composed of the trunk 3 and the leg 2 representing the size of the gap is appropriately determined. Must be in range.
[0018]
Therefore, in the present embodiment, the lengths of the axes 4 a to 4 d of the leg 2, the inclination angles thereof, the length of the axis 5 of the trunk 3, and the maximum value of the width of the leg 2 are special. It is designed to have a ratio of More specifically, as shown in FIG. 4, the length of the axis 4 a to 4 d of the leg 2 is “L”, the inclination angle is “α”, and the length of the axis 5 of the trunk 3 is “M”. As shown in FIG. 3, if the maximum value of the width of the leg 2 is “K”, the concrete block 1 of the present embodiment is designed so that the following relational expression is satisfied.
[0019]
(Equation 1)

[0020]
In this relational expression, the denominator of the fraction on the left side means the maximum value of the vertical cross-sectional area of the leg 2 (the area of the cross section orthogonal to the axis 4), and the numerator is of the rectangle (S) shown in FIG. It means area. The rectangle (S) is an area representing a space between blocks, which is necessary for obtaining good engagement between the plurality of concrete blocks 1.
[0021]
Here, the “area representative of the space between blocks” will be described. For example, when a plurality of concrete blocks 1 are arranged and stacked in layers, as shown in FIG. 5, legs 2 of another concrete block 1 are placed in a space Sa formed between two adjacent concrete blocks 1. Are sequentially engaged, but at this time, if the space Sa is smaller than a certain area, the leg portion 2 cannot enter the space Sa. .
[0022]
In other words, in order to allow the leg 2 of another concrete block 1 to enter and engage with the inter-block space Sa to obtain a good engagement between the concrete blocks 1, the space Sa formed must be Needs to be larger than a certain area in relation to the vertical cross-sectional area. What represents the “constant area” here is the area that represents the inter-block space.
[0023]
The area S representing the interblock space can be calculated as (M + 2Lcosα) Lsinα as shown in the above equation. That is, as shown in FIG. 4, the representative area S can be considered to be represented by a rectangular area having M + 2Lcosα on one side and Lsinα on the other side.
[0024]
Note that “2Lcosα” added to the length “M” of the axis 5 of the trunk 3 is the parallel projection amount of the axis 4a of the leg 2a (the projection amount of the trunk 3 in the direction of the axis 5) shown in FIG. ) And the amount of parallel projection “Lcosα” of the axes 4c and 4d of the legs 2c and 2d. “Lsinα” means the vertical protrusion amount of the axes 4c and 4d of the legs 2c and 2d (the protrusion amount in the direction orthogonal to the axis 5 of the body 3) (see FIG. 4).
[0025]
The area S representing the inter-block space is represented by a relative leg length “Lsin α / K” (ratio of a vertical protrusion amount of the leg 2 to a maximum width of the leg 2) and a relative leg distance “( M + 2Lcosα) / K ”.
[0026]
Since the above relational expression means “the left side is 1.0 or more”, the numerator of the fraction on the left side is equal to or larger than the denominator, that is, the representative area S is prescribes that 2 is the maximum value K ² or more vertical cross-sectional area. Therefore, if the maximum value of the length of the axis 4, its inclination angle, the length of the axis 5, and the width of the leg 2 is set within a range in which this relational expression holds, a good engagement state can be obtained. The concrete block 1 to be used can be designed.
[0027]
Even when the length “L” of the axis 4 of the leg 2 is set to be extremely short, the length “M” of the axis 5 of the body 3 is correspondingly increased by the corresponding amount. Can be designed, but if the axis 4 of the leg 2 is too short, the penetration of the leg into the gap becomes small, and a good engagement state cannot be obtained.
[0028]
Accordingly, while satisfying the above relational expression, the ratio of the length “L” of the axis 4 of the leg 2 to the maximum value “K” of the width of the leg 2 (“L” when “K” is 1) The ratio is preferably set to 0.85 or more.
[0029]
On the other hand, with respect to the structural strength, it is advantageous that the leg 2 and the trunk 3 are short and the cross-sectional width of the leg 2 is large. That is, if the trunk 3 or the leg 2 is too long, the structural strength is reduced, and reinforcement with a reinforcing bar is required. Therefore, it is necessary to set the ratio of the area formed by the trunk and the leg representing the size of the gap to the square of the maximum width of the leg representing the size of the leg in an appropriate range. Therefore, the concrete block 1 of the present embodiment is designed so that the following relational expression holds.
[0030]
(Equation 2)

[0031]
This relational expression stipulates that “the left side is 1.8 or less”, that is, the representative area S is 1.8 times or less the maximum value K ² of the vertical cross-sectional area of the leg 2. It is. According to the results of numerical analysis, if this value exceeds 1.8, there is a problem in structural strength, and if it is 1.8 or less, sufficient structural strength can be obtained without reinforcing with steel bars. Was found.
[0032]
Even if the length “M” of the axis 5 of the body 3 is set to be extremely long, the length “L” of the axis 4 of the leg 2 can be shortened accordingly, and the above relational expression can be obtained. However, if one of the axis 4 of the leg 2 and the axis 5 of the trunk 3 is too long, it is impossible to secure sufficient structural strength without any streaks. Would.
[0033]
Therefore, while satisfying the above relational expression (Equation 2), the ratio of the length “M” of the axis 5 of the body 3 to the maximum value “K” of the width of the leg 2 (“K” is 1) It is preferable to set the ratio (“M”) to 0.9 or less.
[0034]
The concrete block 1 according to the present embodiment is designed in a range that satisfies both of the above two relational expressions (Equations 1 and 2). That is, the ratio between the maximum value K ² of the vertical cross-sectional area of the area S and the leg 2 that represents the space between the blocks is designed to be in the range of 1.0 to 1.8. For this reason, it is possible to obtain a block having not only stability but also excellent performance with respect to structural strength that is incompatible with stability. The ratio of the S and ^{K 2,} it is further preferable to design such that the range of 1.1 to 1.7.
[0035]
Note that the inclination angle α of the axes 4a to 4d of the leg 2 is set to 66 ° in the present embodiment. However, the angle is not necessarily limited to this angle, and can be set arbitrarily within a range of 45 ° to 90 °. The reason why the lower limit is set to 45 ° is that if the inclination angle α is smaller than this, the effect of meshing is reduced, and if the upper limit is set to 90 °, the interblock space is set larger than this. This is because the representative area S is reduced, and it becomes difficult to engage the leg 2.
[0036]
Also, as can be seen from FIG. 3, the leg 2 (for example, the leg 2c) of the concrete block 1 has an outer peripheral surface inclined with respect to the axis 4 (4c) (the auxiliary line 4c in FIG. 3). Is a line parallel to the axis 4c, and the angle β represents the angle of inclination of the outer peripheral surface of the leg 2c with respect to the axis 4c.), And gradually increases in width (from the base end near the body 3 to the tip). (Cross-sectional area) becomes smaller, that is, it has a “tapered” shape. This is because the tapered shape allows the leg 2 to smoothly and easily enter the inter-block space during the installation work.
[0037]
In the present embodiment, the inclination angle β of the outer peripheral surface of the leg 2 is set to 6 °. However, the angle is not necessarily limited to this angle and can be set arbitrarily within the range of 2 ° to 30 °. It should be noted that the lower limit of 2 ° is smaller than this, so that the effect of facilitating and facilitating the installation work cannot be expected so much. On the other hand, the upper limit of 30 ° is larger than this. This is because the legs 2 can enter only a little and the effect of the engagement is reduced.
[0038]
In the present embodiment, the leg 2 has a polygonal cross section, but may have a circular or elliptical cross section. In particular, when the shape is a polygon, the porosity is larger than that of a circular shape, etc., even if the axial dimensions are the same, and the economic efficiency is further improved. As shown in FIG. 1, the tip end face of the leg 2 is formed on the top end face 6 of the concrete block 1 (the tip end face of the leg 2 that does not touch the ground G when placed on the ground G). The angle is set so as to be parallel to G. However, it is not always necessary to set such an angle.
[0039]
Also, as described above, in the present embodiment, the shapes of the legs 2a to 2d are all the same, but the shape of the first pair (the legs 2a, 2b) and the second pair (the legs 2c, 2d). ) Can be configured to have different shapes. In this case, the value of "K" (the maximum value of the width of the leg 2) in the above relational expression (Equation 1 or 2) adopts the value of the smallest leg 2, and "L" and "L" As the value of “α”, a value for the leg 2 other than the leg 2 is adopted.
[0040]
FIG. 6 is an overhead view of the embankment cladding 8 constructed by stacking the concrete blocks 1 of this embodiment in layers, and FIG. 7 shows a state where the embankment cladding 8 is viewed from the side. FIG. As can be seen from these figures, of the four legs 2 of each concrete block 1, the leg 2 facing downward is replaced by the concrete block 1 located in front of the concrete block 1 (below the slope). The concrete blocks 1 can be brought into the interblock space and engaged on the lateral legs 2, and the whole of the concrete blocks 1 arranged can be in an “engaged state”. Therefore, a very stable embankment can be constructed.
[0041]
Further, the concrete block 1 constituting the second layer is not completely placed on the concrete block 1 of the first layer, but is placed only half, and the other half is placed on the concrete block 1 of the first layer. Can be placed on the same plane as the ground plane, and when applied to a two-layer coating as shown, the layer thickness can be reduced. Therefore, the amount of concrete used can be greatly reduced, which is very economical.
[0042]
【Example】
Here, an embodiment of the concrete block according to the present invention will be described. First, three types of block models (A1 to A3) were prepared as concrete blocks according to the present invention, and four types of block models (B1 to B4) were further prepared as comparative examples.
[0043]
Then, a model of the embankment body was created by stacking these block models, and a hydraulic model experiment was performed for each of them to measure the KD value and compare the stability. The results are shown in Table 1.
[0044]
[Table 1]

In the second column of the above table, the ratio of the area representative of the space between blocks and the maximum value of the cross-sectional area of the leg is the value on the left side of the above two relational expressions (that is, (M + 2Lcosα) Lsinα / K ² ).
[0045]
Considering that the KD value of a general four-legged block is 8.3, from this experimental result, "the ratio of the area representative of the space between blocks to the maximum value of the cross-sectional area of the leg" is 1.0. It can be seen that the larger blocks A1 to A3 (the present invention) are all excellent in stability. On the other hand, it was confirmed that the block B1 (comparative example) smaller than 1.0 had the lowest stability among the prepared blocks.
[0046]
Next, the generated stress levels of the blocks A1 to A3 and B1 to B4 were compared by numerical analysis. The results are shown in "Table 2".
[0047]
[Table 2]

The “stress degree ratio” in the above table means a ratio when the stress degree generated in a general straight lined four-legged block is “1”, and the smaller the value, the “the greater the structural strength”. It turns out that.
[0048]
From these experimental results, all of the blocks A1 to A3 (the present invention) in which the “ratio of the area representative of the space between the blocks and the maximum value of the cross-sectional area of the leg” is 1.8 or less have sufficient structural strength. It turns out that it has. On the other hand, it was confirmed that the structural strength of the blocks B2 to B4 (Comparative Example) larger than 1.8 was considerably inferior, and reinforcement with a reinforcing bar or the like was required.
[0049]
【The invention's effect】
As described above, the concrete block according to the present invention has very good stability. Specifically, it is necessary to secure sufficient stability with a mass of about 70% or less of a general quadruped block. Can be. Further, the “structural strength”, which is in a relationship opposite to the stability, has excellent performance, and a block having a sufficient structural strength can be obtained without reinforcing with a reinforcing bar.
[0050]
Therefore, the block cross section can be reduced, and the amount of concrete used can be reduced. In addition, since construction can be performed by a small heavy machine, economic efficiency is improved in terms of not only material costs but also construction costs.
[0051]
Furthermore, in the case of layer coating, since the layer thickness can be reduced, the amount of concrete used can be further reduced as compared with the case of full-section coating. Therefore, when the concrete block according to the present invention is used, the economic efficiency can be drastically improved.
[Brief description of the drawings]
FIG. 1 is a view showing a state in which a concrete block 1 according to the present invention is viewed from an oblique side.
FIG. 2 is a front view of the concrete block 1 shown in FIG.
FIG. 3 is a view showing axes 4a to 4d of legs 2 and an axis 5 of a trunk 3 of the concrete block 1 shown in FIG.
FIG. 4 is an explanatory diagram of an area S representing a space between blocks of the concrete block 1 shown in FIG. 1;
FIG. 5 is an explanatory view of a space Sa formed between the concrete blocks 1 and 1;
6 is an overhead view of the embankment covering work 8 constructed by stacking the concrete blocks 1 shown in FIG. 1 in two layers.
FIG. 7 is a diagram showing a state in which the covering member 8 of FIG. 6 is viewed from the side.
[Explanation of symbols]
1: concrete block,
2: legs,
3: Torso,
4: leg axis,
5: axis of the trunk,
6: Top end face,
7: Haunch,
8: Embankment coating

Claims (2)

It is constituted by one torso located in the center and a total of four legs connected two to each of both ends of this torso,
Each axis of the two legs on one side of the body is in a twisted position with respect to the axis of the other leg,
When the length of the axis of the leg is L, the angle of inclination is α, the length of the axis of the trunk is M, and the maximum value of the width of the leg is K, the value of (M + 2Lcosα) Lsin α / K ² Is in the range of 1.0 to 1.8,
The inclination angle of the axis of the leg with respect to the axis of the trunk is in the range of 45 to 90 °,
A concrete block, wherein the inclination angle of the outer peripheral surface of the leg with respect to the axis of the leg is in the range of 2 to 30 °. The concrete block according to claim 1, wherein a cross section of the leg and / or the trunk is polygonal or circular.

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