Patent Description:
A structure body for civil engineering work obtained as a result of housing filler material in a bag body for civil engineering work has been well known.

A general bag body for civil engineering work includes a bag body made of net fabric having a mesh shape, a lifting rope of an endless structure looped around a mesh in proximity to an opening of the bag body so as to be attached to the bag body, and a mouth-narrowing rope for preventing the opening of the bag body from opening, as described in document <CIT>.

Bag bodies, each of which has a mesh uniform in strength and size as a whole, but each of which is different from other in external dimension, have been used in accordance with their respective volumes (<NUM> to <NUM> t) of filler material.

A method of manufacturing a structure body for civil engineering work through the use of a bag body for civil engineering work <NUM> described in Patent Document <NUM> is explained with reference to <FIG>.

In a state where a bag body <NUM> attached with a lifting rope <NUM> set inside a mold <NUM> is widely opened at its opening, filler material <NUM> is put into the bag body <NUM>.

After the completion of putting the filler material <NUM> into the bag body <NUM>, halfway portions of the lifting rope <NUM> inserted through a mesh of the bag body <NUM> are drawn in loop shapes from a plurality of parts of the bag body <NUM>, respectively, and a plurality of the relevant parts of the lifting rope <NUM> are lifted by a crane or the like so as to take the bag body <NUM> out from the mold <NUM> ((A), (B) of <FIG>).

Under such circumstances where the bag body <NUM> is lightly lifted, by winding a mouth-narrowing rope <NUM> around a top portion of the bag body <NUM> or around a root portion of the lifting rope <NUM>, the opening is closed.

The structure body for civil engineering work (<NUM>) thus completed is transported to a predetermined site and is laid thereon ((C) of <FIG>).

When the completed structure body for civil engineering work (<NUM>) is laid on the site, the filler material <NUM> as a whole is extended in a horizontal direction. For this reason, it has been difficult to secure a desired height.

JPH11-<NUM> discloses that a height of filler material is regulated at a certain level by a reinforcing belt looped around to be attached to a bag body for civil engineering work.

<CIT> discloses that, in a state where a lifting rope is lifted after a bag body for civil engineering work is housed with filler material, an adjustment rope attached to the bag body in proximity to a top end of the housed filler material is adjusted in length so that a height and an outer circumferential dimension of a housing portion of the bag body housing the filler material could eventually be adjusted.

<CIT> discloses a bag body for civil engineering work having some part through which a lifting rope is inserted formed thereon to be larger only in mesh size than other parts formed thereon so that a mesh through which the lifting rope is inserted could be prevented from being torn when the lifting rope is lifted.

Further prior art is disclosed in documents <CIT>, <CIT>, <CIT> and <CIT>.

The conventional bag bodies for civil engineering work or conventional structure bodies for civil engineering work had the technical problems below:.

As described above, for the conventional bag body for civil engineering work, it has been difficult to solve the technical problem in bag-body damage caused by the filler material while maintain the flexibility of the structure body.

In view of the foregoing points, an objective of the present invention is to provide a bag body for civil engineering work and a structure body for civil engineering work that could solve simultaneously a problem in bag-body damage caused by filler material and a problem in mesh torn as a result of lifting a lifting rope, as well as could suppress an amount of net fabric to be used thereby to reduce manufacturing cost of the bag body for civil engineering work.

Further, another objective of the present invention is to provide a bag body for civil engineering work and a structure body for civil engineering work that could secure flexibility so as to absorb unevenness on a laying site, as well as could suppress large translocation of filler material.

One aspect of the present invention is a bag body for civil engineering work according to claim <NUM>.

In still another aspect of the present invention, there may be such a relation between the neck portion of the unhousing portion and a top portion of the bag body without having the intermediate-mouth narrowing rope attached to the unhousing portion that, when the lifting rope is lifted, a lifting angle with respect to the neck portion of the unhousing portion is less than a lifting angle with respect to the top portion of the bag body without having the intermediate-mouth narrowing rope attached to the unhousing portion.

In still another aspect of the present invention, the lifting rope may be positioned between the mouth-narrowing rope and the intermediate-mouth narrowing rope.

Another aspect of the present invention is a structure body for civil engineering work according to claim <NUM>.

According to the above-described aspects of the present invention, at least one of the following effects could be achieved:.

For more thorough understanding of the present invention and advantages thereof, the following descriptions should be read in conjunction with the accompanying drawings in which:.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

Descriptions will be provided with reference to <FIG>, <FIG>, and a structure body for civil engineering work <NUM> includes a bag body for civil engineering work <NUM> (hereinafter, referred to as "bag body <NUM>") and filler material <NUM> which housed in the bag body <NUM>.

The bag body <NUM> includes: a bag body <NUM> to be filled with filler material <NUM>; a mouth-narrowing rope <NUM> attached to the closest position to an opening <NUM> of the bag body <NUM>; a lifting rope <NUM> of an endless structure attached in a lower position with respect to the mouth-narrowing rope <NUM> in proximity to the opening <NUM> of the bag body <NUM>; and an intermediate-mouth narrowing rope <NUM> attached in a lower position with respect to the lifting rope <NUM> at a distance from the opening <NUM> of the bag body <NUM>.

Three ropes <NUM> to <NUM>, the mouth-narrowing rope <NUM>, the lifting rope <NUM>, and the intermediate-mouth narrowing rope <NUM>, are attached to the bag body <NUM> from the opening <NUM> toward a bottom portion <NUM> in this order.

The bag body <NUM> is a net-fabric made bottomed bag provided with the opening <NUM> and the bottom portion <NUM>.

The bag body <NUM> consists of: a housing portion <NUM> for housing the filler material <NUM>; and an unhousing portion <NUM> for not housing any filler material <NUM>.

In an embodiment according to the present invention, in order to suppress wasting the net fabric, the bag body <NUM> manufactured in accordance with an amount of the filler material <NUM> to be housed (e.g., <NUM> to <NUM><NUM>) is used, and such a bag body <NUM> is manufactured through the use of the net fabric having the minimum necessary area corresponding to the amount of the filler material <NUM> to be housed.

As the net fabric of the bag body <NUM>, e.g., an extra-thick Raschel (Russell) net obtained by double knitting a synthetic fiber yarn such as polyester (<NUM> d/<NUM> pieces, strength of <NUM> kgf/<NUM> legs, or fracture elongation of <NUM>%) may be used.

The unfolded shape of a mesh of the net fabric is a quadrangle or hexagon, and the entire range of mesh is uniform. The size of mesh is set such that the filler material <NUM> is prevented from going out of the mesh, and a general mesh size is <NUM> to <NUM>.

In an embodiment according to the present invention, a range within which the filler material <NUM> is housed inside the bag body <NUM> is defined as the housing portion <NUM>, and a range without housing any filler material <NUM> immediately above the housing portion <NUM> inside the bag body <NUM> is defined as the unhousing portion <NUM>.

Further, explanations will be provided hereinafter, with respect to an attachment position, as a boundary, of the intermediate-mouth narrowing rope <NUM>, a lower half of the unhousing portion <NUM> is defined as a shoulder portion 25a, and an upper half of the unhousing portion <NUM> is defined as a neck portion 25b.

The opening <NUM> is formed in an upper portion of the neck portion 25b, and the mouth-narrowing rope <NUM> and the lifting rope <NUM> are attached in advance around the opening <NUM>.

The mouth-narrowing rope <NUM>, positioned above the lifting rope <NUM>, is a rope for opening and closing the opening <NUM> of the bag body <NUM>, and such a rope is attached to the bag body <NUM> such that it is inserted through the mesh in proximity to the opening <NUM>.

Reasons for positioning the mouth-narrowing rope <NUM> above the lifting rope <NUM> are that: the opening <NUM> could be closed without being affected by any lifting rope <NUM>; and a portion caused to occur by gathering the net fabric surrounding the opening <NUM> could be prevented from projecting upward the bag body <NUM>.

By inserting the mouth-narrowing rope <NUM> through the mesh in a stitch-skipping manner, as necessary, the workability of attaching the mouth-narrowing rope <NUM> and the level of closeness of the opening <NUM> could be improved.

The lifting rope <NUM> is a rope, of an endless structure, attached to the bag body <NUM> such that it is inserted through the mesh between the mouth-narrowing rope <NUM> and the intermediate-mouth narrowing rope <NUM>.

The intermediate-mouth narrowing rope <NUM> is a composite rope having the function of causing a constriction to occur at a part of the unhousing portion <NUM> so as to cover to hold the filler material <NUM> as well as the function as a mouth-narrowing rope.

The intermediate-mouth narrowing rope <NUM> is attached to the bag body <NUM> by being inserted through an intermediate portion of the unhousing portion <NUM>, i.e., by being inserted through the mesh between an attachment position of the lifting rope <NUM> and a top end of the filler material <NUM>.

The intermediate-mouth narrowing rope <NUM> is attached so as to cause the constriction to occur at the part of the unhousing portion <NUM> in order that a lifting angle with respect to a top portion of the bag body <NUM> (neck portion 25a) is reduced, when the lifting rope <NUM> is lifted, so as to prevent the mesh through which the lifting rope <NUM> is inserted from being torn, and that, after the structure body for civil engineering work <NUM> is laid, a circumferential edge portion of a top end surface of the filler material <NUM> is elastically covered to be held with the shoulder portion 25a of the unhousing portion <NUM>.

By selecting an attachment height of the intermediate-mouth narrowing rope <NUM> and a size of the occurring constriction (a constriction diameter) with respect to the unhousing portion <NUM>, it is possible to adjust a lifting angle with respect to the top portion of the bag body <NUM>, an area of the circumferential edge portion of the top end surface of the filler material <NUM> covered to be held with the shoulder portion 25a of the unhousing portion <NUM>, and a burden of load to be imposed on the intermediate-mouth narrowing rope <NUM>.

The attachment height of the intermediate-mouth narrowing rope <NUM> and the size of the occurring constriction are selected appropriately in consideration of an external dimension of the bag body <NUM>, and an amount of the filler material <NUM> to be housed or the like.

For the filler material <NUM>, natural aggregates such as a boulder, concrete rubble, fired material of various sorts of wastes, or the like may be applied.

When the filler material is used for foot protection works, such filler material <NUM> has a diameter of approximately <NUM>, and a size of the filler material <NUM> may be selected appropriately in accordance with purposes.

Subsequently, a method of manufacturing the structure body for civil engineering work <NUM> using the bag body <NUM> will be described with reference to <FIG>, <FIG>.

A mold <NUM> in an inverted truncated-cone shape (grinding-bowl shape) having both sides longitudinally opened is prepared.

The bag body <NUM> is set inside the mold <NUM>. The bag body <NUM> in proximity to the opening <NUM> widely opened is outwardly folded so as to cover a peripheral edge of an upper opening of the mold <NUM>.

A predetermined amount of the filler material <NUM> is put into the bag body <NUM> through the use of heavy machinery such as a backhoe.

After completing the step of putting the filler material <NUM> into the bag body <NUM>, the intermediate-mouth narrowing rope <NUM> attached to the unhousing portion <NUM> is narrowed to a predetermined circumferential length whose diameter is less than a diameter of the housing portion <NUM>, while the bag body <NUM> being set inside the mold <NUM>, and then, both ends of the intermediate-mouth narrowing rope <NUM> are firmly tied to each other by a tie or the like so as to be prevented from being easily released from each other.

Such a "predetermined circumferential length" includes a circumferential length of a constriction at which, by the constriction caused to occur by the intermediate-mouth narrowing rope <NUM> of said length, both of: the function of preventing the mesh through which the lifting rope <NUM> is inserted from being torn after the completion of the structure body for civil engineering work <NUM>; and the function of covering to hold the top end surface of the filler material <NUM> with the shoulder portion 25a of the unhousing portion <NUM>, could be performed.

The step of narrowing the intermediate-mouth narrowing rope <NUM> is started from a state where the unhousing portion <NUM> is untightened (loosened), and therefore the narrowing could be performed with a relatively small force.

It is to be noted that the intermediate-mouth narrowing rope <NUM> may be attached to the bag body <NUM> in advance, or may be attached to the bag body <NUM> on a laying site after completing the step of putting the filler material <NUM> into the bag body <NUM>.

In a state where the unhousing portion <NUM> is untightened (loosened), the mouth-narrowing rope <NUM> is narrowed so as to close the opening <NUM> of the bag body <NUM>.

The mouth-narrowing rope <NUM> is positioned above the lifting rope <NUM>, and therefore, the opening <NUM> could be closed without being affected by the lifting rope <NUM>.

It is to be noted that <FIG> shows the opening <NUM> in a state where it is opened for indicating its position; however, the opening <NUM> is actually closed to such an extent that the filler material <NUM> is prevented from leaking out from the bag body <NUM>.

After closing the opening <NUM> of the bag body <NUM>, drawing portions of the mouth-narrowing rope <NUM> are tied together so as not to be released.

It is to be noted that the step of narrowing the mouth-narrowing rope <NUM> and the step of narrowing the intermediate-mouth narrowing rope <NUM> may be performed in this order, or vice versa.

Halfway portions of the lifting rope <NUM> inserted through the mesh of the bag body <NUM> are drawn in loop shapes from a plurality of parts (e.g., six parts) of the bag body <NUM>, and a plurality of the relevant parts of the lifting rope <NUM> are hung on a hook <NUM> of a crane or the like.

The lifting rope <NUM> is lifted so as to take the bag body <NUM> out from the mold <NUM>, and as a result, the structure body for civil engineering work <NUM> is finished being manufactured.

The structure body for civil engineering work <NUM> thus completed is transported to a predetermined site and is laid thereon (<FIG>).

Subsequently, the major characteristics of the structure body for civil engineering work <NUM> will be described.

The lifting angle with respect to the unhousing portion <NUM> formed by the intermediate-mouth narrowing rope <NUM> will be described with reference to <FIG>.

<FIG> shows (A) reference of the bag body <NUM> lifted through the lifting rope <NUM> without any intermediate-mouth narrowing rope <NUM>, and (B) example of the bag body <NUM>, according to the present invention, attached with the intermediate-mouth narrowing rope <NUM> at a part of the unhousing portion <NUM> while being lifted through the lifting rope <NUM>.

The bag bodies <NUM> shown in (A) and (B) of <FIG> are assumed to be the same in size and in amount of the housed filler material <NUM>.

In the reference shown in (A) of <FIG>, the lifting angle formed, when the bag body <NUM> is lifted through the lifting rope <NUM>, without any intermediate-mouth narrowing rope <NUM> is assumed to be θ<NUM>, and the lifting height of the unhousing portion <NUM> is assumed to be H<NUM>.

In an example according to the present invention shown in (B) of <FIG>, when the lifting rope <NUM> is lifted, the entire range of the unhousing portion <NUM> of the bag body <NUM> is to be formed into a uniform cone shape; nevertheless, such an increase in diameter of the unhousing portion <NUM> is regulated by the intermediate-mouth narrowing rope <NUM>, and as a result, a constriction is so caused as to occur at a part of the unhousing portion <NUM>.

As a result of the constriction caused to occur at a part of the unhousing portion <NUM>, two lifting angles, θ<NUM> with respect to the neck portion 25b and θ<NUM> with respect to the shoulder portion 25a, could be formed in the unhousing portion <NUM>.

Relation among Lifting Angles θ<NUM>, θ<NUM>, and θ<NUM> are as follows:.

In such a manner, a relation of θ<NUM> < θ<NUM> < θ<NUM> holds true.

As a result of comparison in lifting height of the unhousing portion <NUM> between the example and reference, the lifting height H<NUM> of the unhousing portion <NUM> of the example according to the present invention is shorter in length than the lifting height H<NUM> of the unhousing portion <NUM> of the reference by a level of height corresponding to the constriction caused to occur by the intermediate-mouth narrowing rope <NUM> provided at a part of the unhousing portion <NUM> (H<NUM> > H<NUM>).

In the reference, if the lifting height H<NUM> of the unhousing portion <NUM> is reduced so that an amount of net fabric to be used for making the bag body <NUM> is reduced, the lifting angle θ<NUM> increases, and as a result, there is a higher probability that the mesh through which the lifting rope <NUM> is inserted would be torn.

In the reference, the lifting angle θ<NUM> with respect to the unhousing portion <NUM> and the lifting height H<NUM> of the unhousing portion <NUM> are so related as to affect each other.

In contrast to the above, in the example according to the present invention, the lifting angle θ<NUM> with respect to the neck portion 25b and the lifting height H<NUM> of the unhousing portion <NUM> are not so related as to affect each other, and therefore the lifting angle θ<NUM> with respect to the neck portion 25b could be reduced without being affected by any lifting height H<NUM> of the unhousing portion <NUM>.

As a result, in the example according to the present invention, the lifting height H<NUM> of the unhousing portion <NUM> could be reduced as well as the lifting angle θ<NUM> with respect to the neck portion 25b through which the lifting rope <NUM> is inserted could be reduced, and as a consequence, an amount of net fabric to be used for making the bag body <NUM> could be reduced while the mesh through which the lifting rope <NUM> is inserted could reliably be prevented from being torn.

As a method of causing a constriction to occur in the unhousing portion <NUM>, a method of tying the intermediate-mouth narrowing rope <NUM> after the lifting rope <NUM> is lifted may be considered.

Such a constriction-formation method connotes the occurrence of a problem that the mesh of the bag body <NUM> through which the lifting rope <NUM> is inserted is torn at the beginning of the lifting as well as a problem that a relatively large tightening force for tightening the unhousing portion <NUM> applied with a tension is needed.

For this reason, in an embodiment according to the present invention, the intermediate-mouth narrowing rope <NUM> is attached to a part of the unhousing portion <NUM> in such a manner that said part is prevented from being enlarged in diameter before the lifting, and then, a constriction is caused to occur at said part of the unhousing portion <NUM> with the aid of a lifting force.

In such an embodiment according to the present invention, therefore, it is not necessary to tie the intermediate-mouth narrowing rope <NUM> with a relatively large force in order to cause a constriction to occur, and further, any large tearing force is not generated in the mesh through which the lifting rope <NUM> is inserted at the beginning of the lifting.

<FIG> shows a reference having the filler material <NUM> housed therein, and thereafter, having the entire range including the top end surface of the housed filler material <NUM> tightened firmly by the bag body <NUM> through the intermediate-mouth narrowing rope <NUM>.

In the reference, the filler material <NUM> is a hindrance to such an extent that it is difficult to tighten firmly the intermediate-mouth narrowing rope <NUM> only with a force exerted by a human operator, and a burden of load for enlarging the intermediate-mouth narrowing rope <NUM> in diameter at the time of the lifting is extremely enlarged.

In an embodiment according to the present invention, as shown in <FIG>, before the lifting, no tension is applied to the unhousing portion <NUM>, and therefore a diameter-enlarging force is not generated on the intermediate-mouth narrowing rope <NUM>. As shown in <FIG>, when the lifting rope <NUM> is lifted, a diameter-enlarging force is generated on the intermediate-mouth narrowing rope <NUM> for the first time.

When the lifting rope <NUM> is lifted, a slight margin is generated in the spread of the net fabric of the shoulder portion 25a of the unhousing portion <NUM>, and by virtue of such a margin of the net fabric, in comparison with reference shown in <FIG>, a burden of load for enlarging the intermediate-mouth narrowing rope <NUM> in diameter decreases.

A covering/holding action on the filler material <NUM> by the bag body <NUM> will be described with reference to <FIG> showing a state where the structure body for civil engineering work <NUM> is laid on a laying site.

In order for the intermediate-mouth narrowing rope <NUM> to restrict the extended net fabric of the shoulder portion 25a of the unhousing portion <NUM> within a certain range, the circumferential edge portion of the top end surface of the filler material <NUM> is elastically covered to be held with the shoulder portion 25a of the unhousing portion <NUM>.

As described above, in an embodiment according to the present invention, the entire range of the group of pieces of filler material <NUM> could be elastically covered to be held, by a combination of the bag body <NUM> and the intermediate-mouth narrowing rope <NUM>, by taking advantage of the elasticity of the net fabric of the housing portion <NUM> and the shoulder portion 25a of the unhousing portion <NUM> of the bag body <NUM>.

As a result, at a time when the structure body for civil engineering work <NUM> is manufactured, at a time when the structure body for civil engineering work <NUM> is translocated, and at a time after the structure body for civil engineering work <NUM> is laid on the laying site, the free movement of the filler material <NUM> could be suppressed by the covering/holding action of the bag body <NUM>, and thereby, it is possible to reduce effectively the net-fabric tear caused by the filler material <NUM>.

The intermediate-mouth narrowing rope <NUM> could, in a cooperative relation with the shoulder portion 25a of the unhousing portion <NUM>, not only cover to hold the filler material <NUM> but also serve as a mouth-narrowing rope.

Even if the top end surface of the filler material <NUM> is to collapse at a time of taking out from mold or at a time of translocation, the collapse of the filler material <NUM> could be effectively suppressed by the shoulder portion 25a of the unhousing portion <NUM> covering the top end surface of the filler material <NUM>.

In such a manner, the collapse of the filler material <NUM> could be effectively suppressed by the shoulder portion 25a of the unhousing portion <NUM> of the bag body for civil engineering work <NUM>, and thereby, it is possible to resolve a technical problem of the net-fabric tear caused by the collapse of the filler material <NUM>.

As shown in <FIG>, in the reference having the entire range of filler material <NUM> tightened by the bag body <NUM>, such a tightening effect on the filler material <NUM> is so large that the structure body for civil engineering work <NUM> losing the flexibility could not sufficiently follow unevenness of a laying surface.

In contrast to the above, in an embodiment according to the present invention, as shown in <FIG>, the entire range of the group of pieces of filler material <NUM> could be elastically covered to be held, by the housing portion <NUM> of the bag body <NUM> in a cooperative relation with the shoulder portion 25a of the unhousing portion <NUM> attached with the intermediate-mouth narrowing rope <NUM>.

As a result, the flexibility of the structure body for civil engineering work <NUM> could be maintained, and thereby, the unevenness of the laying surface could be followed.

As already described, the spill of the filler material <NUM> housed in the bag body <NUM> could be regulated by the intermediate-mouth narrowing rope <NUM>, and thereby, a burden to be imposed on the mouth-narrowing rope <NUM> could be significantly reduced.

Claim 1:
A bag body for civil engineering work (<NUM>) comprising:
a bag body (<NUM>) having a mesh shape capable of housing filler material, wherein the bag body (<NUM>) consists of a housing portion (<NUM>) for housing a predetermined amount of filler material at a lower half thereof and an unhousing portion (<NUM>) for not housing any filler material at an upper half thereof;
a mouth-narrowing rope (<NUM>) for opening/closing an opening (<NUM>) of the bag body (<NUM>); and
a lifting rope (<NUM>) of an endless structure inserted through a mesh in an upper portion of the bag body (<NUM>) so as to be attached to the bag body (<NUM>),
characterized by further comprising:
an intermediate-mouth narrowing rope (<NUM>),
wherein said bag body for civil engineering work (<NUM>) is configured such that:
the bag body (<NUM>) is attached with the intermediate-mouth narrowing rope (<NUM>) at a part of the unhousing portion (<NUM>) thereof in a lower position with respect to the lifting rope (<NUM>); and
the bag body (<NUM>) has, when the lifting rope (<NUM>) is lifted, a constriction occurring at a part of the unhousing portion (<NUM>) thereof attached with the intermediate-mouth narrowing rope (<NUM>);
wherein the unhousing portion (<NUM>) has: a shoulder portion (25a) formed at a lower half thereof with respect to the constriction as a boundary, the shoulder portion (25a) being capable of covering to hold a circumferential edge portion of a top end surface of filler material; and a neck portion (25b) formed at an upper half thereof with respect to the constriction as a boundary, the neck portion (25b) being attached with the mouth-narrowing rope (<NUM>) and the lifting rope (<NUM>); and
wherein there is such a relation between the neck portion (25b) of the unhousing portion (<NUM>) and the shoulder portion (25a) of the unhousing portion (<NUM>) that, when the lifting rope (<NUM>) is lifted, a lifting angle with respect to the neck portion (25b) is less than a lifting angle with respect to the shoulder portion (25a).