GB2068434A - Concrete block - Google Patents

Abstract

Concrete blocks for construction work such as for shore or river bank protection comprise a main body (1) whose transverse cross-section is of the shape of two dovetails symmetrically joined along their shorter parallel edges with one or more bores (2) axially through the main body (1). <IMAGE>

Description

SPECIFICATION Concrete construction block The present invention relates to concrete blocks for use in construction work e.g. for shore or river bank protection and the like.

Heretofore, concrete blocks of various configurations have been widely used in construction work for shore-protection. However, those concrete blocks have not been really satisfactory because their structures are not simple and their application cannot be effective in every case.

An object of the present invention is to provide an improved concrete construction block which is simple in structure and yet reasonably applicable for most construction work such as for shoreprotection and the like.

According to the present invention, a concrete construction block is characterised in that it is of columnar configuration, whose transverse crosssection perpendicular to its column axis is of the shape of two dovetails symmetrically jointed along their shorter parallel edges, and in that one or more bores penetrate axially through the main body.

The above-mentioned and other features and objects of the present invention will become more apparent by reference to the following description of one preferred embodiment taken in conjunction with the accompanying drawings, in which: Figure 1 is a plan view showing the preferred embodiment of a concrete block of the present invention; Figure 2 is a front view of the concrete block shown in Figure 1; Figures 3 to 6 are plan views of modified forms of the concrete block shown in Figures 1 and 2; Figures 7 to 9 are plan views illustrating concrete blocks of the present invention in three different arrayed conditions; Figures 10 to 14 are longitudinal cross-section views showing arrays of the concrete blocks of the present invention as used for the revetment of a front slope of a river bank; and Figures 1 5 and 1 6 are a plan view and a longitudinal cross-section view, respectively, of an array of the concrete blocks of the present invention as used in bottom-protection work for a river bed.

As shown in Figures 1 to 6, the present invention provides a concrete block A which consists of a columnar main body of concrete 1, the transverse cross-section of the main body 1, taken at right angles to its column axis, having the shape of two dovetails symmetrically jointed along their shorter parallel edges. In addition, one or more (preferably two) bores 2 are formed in the main body penetrating therethrough in the direction of its column axis. It is preferable to form the bores so as to penetrate through their respective dovetail-shaped halves in a symmetric fashion. Not only the shape and size of the penetrating bores 2, but also the size of the crosssection of the main body 1, could be selected appropriately according to the purpose of use.In addition, the axial length of the main body 1 may be decided appropriately so as to meet the requirements for the construction work in which the concrete blocks are to be used.

As shown in Figure 7, in the case where the concrete blocks A of the present invention are to be used against the surface of a structure, a multiplicity of the concrete blocks A are arranged in succession in a plurality of staggered columns with the parallel side surfaces of adjacent concrete blocks A in each column abutting each other so that a recessed portion 1 a at the centre of one non-parallel side surface of a concrete block A in one column may engage with adjacent dovetailshaped protrusions 1 b of a pair of adjacent concrete blocks in the next succeeding column.

Thus, owing to the intermeshing between the concrete blocks A in the adjacent columns, each concrete block A can be firmly held in position, and hence, the concrete blocks A can be arrayed so as not to be scattered by external forces.

Figure 8 shows a modified arrangement in which the concrete blocks A are arrayed with small gap clearances interposed between adjacent ones, and Figure 9 shows a further modified arrangement with much greater gap clearances between adjacent concrete blocks.

Figures 10 to 14 show the arrangement of the concrete blocks A of the present invention as used in the revetment of a front slope of a river bank.

Since the main bodies 1 of the concrete blocks A of the present invention have a columnar configuration, whose transverse cross-section perpendicular to its column axis is of the shape of two dovetails symmetrically jointed along their shorter parallel edges, and since they are arrayed in a plurality of staggered columns so that a recessed portion 1 a at the centre of one nonparallel side surface of a concrete block A in one column may engage with adjacent dovetailshaped protrusions 1 b of a pair of adjacent concrete blocks in the next succeeding column as described previously, the concrete blocks A can be so firmly held in position by their intermeshing, that the array of the concrete blocks A has a sufficient mechanical'strength even with dry masonry and there is no need to employ wet masonry.Moreover, since the main block 1 of the concrete block A has bores 2 penetrating therethrough in its axial direction, water can communicate between the front and rear faces of the pile of concrete blocks on a face slope, which enables the water height and pressure to be levelled out on both sides. Therefore, suction of water through the pile of concrete blocks does not occur, and thus there is not need to provide cut-off plates nor sheet piles.In addition, inasmuch as the respective concrete blocks A are firmly held in their predetermined positions by the intermeshing between the concrete blocks and are not likely to fall away even under uneven subsidence of the ground, the revetment of a front slope of a river bank utilizing the concrete blocks A of the present invention is highly resistive against scouring of the foundation, and, as a result, sheet piles for the foundation become unnecessary. It is to be noted, however, that at a place where scouring of the foundation is especially violent, sacrifice blocks are to be used in front of the revetment array of the concrete blocks A.

Furthermore, appropriate roughness on the revetment surface can be provided by selecting an adequate mode of piling or arraying of the concrete blocks A. In the arrangement shown in Figure 1 concrete blocks A are piled together so that the front end- surfaces of the concrete blocks A at the successive levels are positioned in a staggered relationship, while in the arrangement shown in Figure 13, concrete blocks A of different axial lengths are alternately arrayed, both for the purpose of increasing a surface roughness of the revetment array. These revetment arrays having a large surface roughness are advantageous at a place where a flow velocity of water is high.

The concrete blocks A in the above-described revetment array also serve as fish net blocks utilizing the bores 2 penetrating axially through the main body 1. Also, since the depth of the bores 2 is large, the block main body contacts with water both inside and outside, and thus the contact area between the concrete block A and water is large; the concrete block A is suitable for adhesion and growth of algae, and owing to the purifying effect of the algae, oxidation and purification capabilities for the river water can be enhanced. Therefore, the concrete blocks A of the present invention are very suitable for use in the revetment of a bank of a river in a city.

Moreover, the concrete blocks A of the present invention can be advantageously assembled as described above, and even if one of the concrete blocks A in an assembly should fall away, there is little risk that any more concrete blocks might also fall away, or might be damaged due to the fall away of the first concrete block A.

The penetrating bores 2 in the main body 1 of the concrete block A enable a backfill of broken stones 3 to be made on the rear face of the revetment array. As shown in Figure 14, the backfill layer of broken stones 3, and the array of the concrete blocks A is integrally jointed; thus the mechanical strength and stability of the revetment array of the concrete blocks A is further enhanced.

In addition, the concrete block A of the present invention is equally applicable to back slope lining for a rivershore or a seashore bank. In that case, the concrete blocks A are arrayed and held against the back slope of the bank with the blocks either tightly contacting with each other, or with appropriate gap clearances retained therebetween, gravel, broken stones or clay being filled in the bores 2 and/or tne gap clearances.

Also, wild turf, grass, willow, etc. can be planted in the bores 2 and/or gap clearances so that the amount of penetration of rain water and/or overtopping water from the face slope can be greatly reduced, resulting in strong resistance against erosion of the face slope caused by rain water and/or overtopping water. Therefore, the back slope lining by means of the concrete blocks A of the present invention provides good resistance against overflow and overtopping of water beyond a bank to the same extent as the heretofore known back slope lining making use of a concrete coating, lattice work, asphalting etc.

Since the lining of a bank by means of the concrete blocks A of the present invention is gaspermeable it has an advantage that a draining effect for the water in the interstices within the bank can be achieved and accordingly the water pressure in the interstices will not become high Moreover, since the intermeshing of the concrete blocks A of the present invention is, as described above, very effective, bank lining by means of the concrete blocks A of the present invention has a great resistance against fall away and/or sliding bf the blocks.

Furthermore, the concrete blocks A of the present invention can be used as downstream ground sills and front aprons such as ground sills of rivers, river bed girdles, water gates, dams, channel works, sediment control dams, head works, etc., as shown in Figures 1 5 and 16, and they serve to achieve damping of water flow energy and to prevent scouring of the bottom of the river.

In these cases, the length of the concrete blocks A as well as the difference in length between the longer and shorter blocks can be appropriately varied in accordance with the environmental conditions, and by filling various sizes of broken stones in the gap clearances between the blocks and in the penetrating bores 2, the blocks can be fixed and the bottom of the river is protected against the scouring. Even if a part of the bottom of the river should be scoured, some of the concrete blocks A shall be immediately displaced after the scouring, and thereby abnormal scouring can be prevented. In addition, since the concrete blocks A can be solidly intermeshed as described above, there is very little fear that the concrete blocks A might successively flow away from the downstream end of the lining.

Claims (3)

1. A concrete block for construction work, characterised in that it is of columnar configuration, whose transverse cross-section perpendicular to the column axis is of the shape of two dovetails symmetrically jointed along their shorter parallel edges, and in that one or more bores penetrate axially through the main body.

2. A concrete block according to Claim 1, characterised in that said bore or bores penetrate the respective dovetail-shaped halves in a symmetrical fashion.

3. A concrete block for construction work, constructed and adapted for use substantially as hereinbefore described with reference to the accompanying drawings.