EP1557497A1 - Leightweight, deformable, isotropic fill - Google Patents

Abstract

The filling has a drain (2) for avoiding arresting of water on an inclined ground (1). Overlapped pneumatics (3) are placed in bulk, and are confined by an open or closed fillet (4) and/or by cables (5) connecting different units. A cable (12) is connected to a vertical anchor (11) on the ground. The anchor is in resistant connection with the pneumatics or fillet.

Description

The present invention relates, in the field of civil engineering, a flexible and lightened work, whose resistance shearing is devoid of structural anisotropy, and which undergoes ranges of deformations modulable.

la constitution de remblais, au moins partiellement hors sol, destinés à supporter des charges, permanentes ou non; la rétention d'éléments solides instables.

It is characterized by the use of tires of any size, arranged in bulk.
..... Associated or not with other materials, the tires in bulk constitute, thanks to the properties stated above, a medium usable in various applications, whose number of variants is not limiting. Two of them are successively described below, with regard to current techniques. They concern:

the constitution of embankments, at least partially above ground, intended to support loads, permanent or not; the retention of unstable solid elements.

Embankments are traditionally made of earth, loose or containing, in whole or in part, fragments rocky, possibly mixed with artificial elements, such as concrete blocks, incorporating the case appropriate elements intended in particular to confine it, to reduce its overall density by the inclusion of materials light, or to improve its mechanical characteristics by the combination of other materials as elements metal or textile tablecloths or the like.

The limits of these embankment embodiments and the improvement provided by the invention are as follows:

The earth has a density of about 2. When an embankment is to be made at a given level on a compressible soil, the weight of the earth embankment causes settlement, and beyond that, a rupture of the surrounding soil, requiring expensive work to improve soil lift or carry loads to a deeper level. The replacement of the earth with concrete, even alveolar, modifies little the pressure applied to the surrounding soil.

Various lightweight materials have been substituted for the earth, including expanded polystyrene and tires. In addition to its high price, polystyrene is very little deformable; we can not give to its elementary blocks an appropriate form except by cutting it. In addition, the contact surfaces between elementary blocks constitute, in the shear strength of the assembly, discontinuities where the roughness is substituted for the internal friction of the material, forcing, at least, to arrange these discontinuity surfaces in directions preference given the field of constraints to which the whole is subject.
An old application of tires consists of their stacking, vertical or not. They are sometimes filled with earth whose density then prevails; when they are stacked without the addition of soil, the contact surfaces between the tires constitute so many discontinuities, partially reducible by the provision of complementary elements of traction. The anisotropy of the medium thus constituted remains however a critical weakening element.

On the contrary, at the scale of a backfill, the tires arranged in bulk constitute as many elementary grains. In addition to an overall density which is a large submultiple of that of the earth, the internal friction they confer on the embankment is isotropic. It is, by nature, much higher than that brought by elementary roughness because the entanglement of the tires, equivalent to grains of concave shapes, makes that, overall, the solicitations to the shear mobilize, among others, the tensile strength of tires.

In addition, the medium consisting of loose tires is susceptible to deformations, in elastic and plastic, which, depending on the use of the embankment, can be significantly reduced by an equivalent pre-load.

In a preferred form, the bulk tires are confined by webs, eg in waterproof textiles or letting the water filter out. These sheets may be interconnected by tie rods, which provide a constraint, or a pre-stress, to provide for example a deformation under an equivalent load to bring. Containment or incorporation may be rigid or deformable materials.
In addition, the slope angle of a backfill loose materials being of the same order as its internal friction angle, these ancillary devices allow, almost at will, to stiffen the embankment of the fill of loose tires.
Finally, other materials, eg vegetated earth, may cover or be incorporated into loose tires, eg from a textile web.

In addition to the aboveground fill, bulk tires can be used to be incorporated into existing soil, after excavation or not, in order to confer all or part of the properties described above.

The following application of the invention is more specific. To retain unstable solid elements, of all dimensions, of natural or artificial origin, it involves, in its variants, other constituent elements, but bulk tires are, at the very least, one of the determining elements of the devices described.

It concerns in particular the retention of boulders which, coming off slopes or cliffs, are likely to disturb or damage natural sites or downstream facilities or dwellings, on their trajectory. Hereinafter the word: block refers to all types of elements to remember.

• soit des filets tendus au-dessus du sol et fixés à des éléments rigides, comme des poteaux,
• soit des digues dont l'élément constitutif principal est habituellement la terre, qui peut être aménagée par criblage et/ou par compactage et/ou par introduction d'éléments améliorant ses caractéristiques mécaniques utiles (résistance à la rupture, pentes de talus, compressibilité), tels le béton (qui peut, dans certains cas être même substitué à la terre), ou des éléments ou nappes métalliques, textiles, ou analogues (terre armée; géotextiles; pneus empilés, parallèlement entre eux, remplis de terre, avec ou sans interfaces; pneus empilés et accolés, rassemblés entre eux par des cables), ces divers ouvrages étant ci-après désignés par le terme de: digues,
• soit des excavations servant de pièges,
• soit une combinaison de cette dernière technique avec l'une des deux autres.

The techniques usually used are:

• nets stretched above the ground and attached to rigid elements, such as poles,
• either dikes whose main constituent element is usually earth, which can be arranged by screening and / or compaction and / or by introduction of elements improving its useful mechanical characteristics (breaking strength, slope slopes, compressibility) such as concrete (which may in some cases be even substituted for the earth), or elements or sheets of metal, textiles, or the like (reinforced earth, geotextiles, tires stacked, parallel to each other, filled with earth, with or without interfaces, stacked and contiguous tires, assembled together by cables), these various works being hereinafter referred to as dikes,
• excavations used as traps,
• a combination of this last technique with one of the other two.

In addition to the need for a dimensioning allowing the net on all its surface and its fixing elements on the ground, to support, without breaking, the impact of a block or several successive blocks, the technique of nets disadvantages of its implementation (procurement and implementation of elements), as well as those inherent to its limited life when the net, except special constituents, is subject to the agents atmospheres, especially ultraviolet.

Excavation traps reduce the stability of the soil where they are made. When it comes to a soft soil or sloping ground, embankments or, for all things, scree, the provisions necessary to compensate for the instability are prohibitive. In addition, the procurement of the instruments necessary for their realization can also be a serious obstacle.

To provide a sufficient resistance to the shear induced by the impact of a block, the dikes bring, by their dimensions and by the density of their components, an overload which, without disproportionate with the structure, may be incompatible with the lift of the soil, especially in extreme cases solicitation (large sliding, sliding under the base, punching, overturning, earthquakes). In addition supply (when there are no suitable materials close to the site, or when local can lead to structural or aesthetic disorders), weight, volume, and size of the elements components and implementation tools, may be incompatible with existing infrastructures (roads, tracks, urban areas or poorly passable).

Existing processes using tires have the drawbacks of forming massifs anisotropic, with preferential sliding surfaces, especially at the interfaces between tires and at the limit of massive thus formed, especially in contact with the ground - which significantly reduces their overall strength.

The device according to the invention makes it possible to overcome these various disadvantages. It is characterized by the contribution prefabricated elements - preferentially bulk tires - of low overall density, and globally isotropic, quite compressible to power, assembled, in the required location and dimensions, to absorb without breaking the impact energy of the blocks, without significantly overloading the soil, nor being significantly sensitive to the agents atmospheric, and requiring only a light infrastructure.

Sur un sol de pente quelconque (1), aménagé, si nécessaire, par un drain de profondeur convenable (2), pour ne pas retenir les eaux courantes, on dispose un ensemble, auto-stable ou non, d'éléments légers (n'excluant pas, partiellement, le polystyrène expansé ou d'autres matériaux légers), pneumatiques (3), neufs ou, de préférence, usagés, de dimensions de préférence diverses, disposés majoritairement en vrac, confinés, de préférence mais pas nécessairement, par des sacs ou par des filets (4), ouverts ou fermés, contenant les pneus, et/ou par des cables (5) reliant les divers éléments entre eux et, préférentiellement, les reliant avec des éléments externes participant à la stabilité du dispositif, filets et cables dimensionnés, ou non, pour contribuer notablement à la résistance de l'ensemble aux impacts de blocs. La disposition en vrac d'une partie au moins du massif et les tailles diverses des pneus enchevêtrés, dont le comportement équivaut à celui de grains concaves, confèrent au massif un fort frottement interne, globalement isotrope, ainsi qu'un frottement externe (au contact du sol entre autres). Les liaisons entre pneus permettent une plus grande diffusion latérale des impacts.

In its preferred form, the device is shown in section in FIG.

On a floor of any inclination (1), laid out, if necessary, by a suitable depth drain (2), in order not to retain running water, there is a set, self-stable or not, of light elements (n not excluding, in part, expanded polystyrene or other lightweight, pneumatic (3) materials, new or, preferably, used, preferably of various sizes, predominantly in bulk, confined, preferably but not necessarily, by bags or nets (4), open or closed, containing the tires, and / or cables (5) connecting the various elements together and, preferably, connecting them with external elements contributing to the stability of the device, nets and cables dimensioned, or not, to contribute significantly to the resistance of the whole to the impacts of blocks. The bulk arrangement of at least a portion of the solid mass and the various sizes of the entangled tires, whose behavior is equivalent to that of concave grains, confer on the solid a strong internal friction, globally isotropic, as well as an external friction (in contact with soil, among others). The connections between the tires allow a greater lateral diffusion of the impacts.

Tires may also not be confined, or be partially or completely confined by soil, depending on local conditions.

In appropriate places according to the needs case by case, especially if it is useful for its dimensioning, or at the protection against attacks (including those of ultra-violet) or aesthetics, the device can be equipped with natural, earth or block coatings, (6), optionally vegetated or seeded (7) and / or coatings artificial, superficial (8) - stacked tires stiffening the upstream front in Figure 1 - or incorporated in the work (9), intended to spread the impact over a larger area and / or volume of the structure, or to contribute to its stability, either directly by their own characteristics or by their influence on other (10) geotextiles filtering the pavement soil).

To provide the structure with greater shear strength, particularly for its stability and the impact of blocks, anchors made of resistant materials, such as metal profiles, can bind the structure to resistant elements, such as foundation soil or other natural or artificial elements (rocks or blocks). In FIG. 1 is thus represented, upstream of the basic device, a vertical anchorage - or, if necessary, several anchors, vertical or inclined - embedded in the ground (11) which can be arranged in one or more elements integral, to which is connected or supported a cable (12), perpendicular to the plane of the section shown, itself in resistant connection with the tires or with the threads - in particular by cables spaced parallel to the plane of the Figure (1) -, so that all or part of the solicitation is transmitted to the ground and to the anchorage without discontinuity. the work submitted to the occurrence of a block. To the only external friction of the tire mass on its base, then adds, to ensure its stability especially during the occurrence of a block, the shear strength of the foundation soil and anchoring, through the connections between the anchor and the tires or tire clusters.

Depending on the slope of the terrain and the expected impact, a stop may be arranged downstream of the structure (not shown), which can also be anchored.

In a variant not illustrated, the structure may be partially buried and / or provided with a ditch on its face upstream. In another variant not illustrated, the basic device, (3), can be put in place on either side of the anchored element. All these elements complementary to the element (3) are provided only as needed.

The low average density of the constituents of the structure makes it possible in particular not to significantly affect the stability of the surrounding environment, even if it is a soil in limit of stability like a scree, to let circulate a running water, permanent or not, thanks to the large porosity various tires in bulk, and finally, if necessary, to bring all or part of the constituents by air from a storage point - helicopter tire bags or tire release and other components -.

The additional anchoring device gives the assembly, when necessary, resistance to the impact of blocks far superior to that of an earthen dyke, even armed with geotextiles or trellises, because it allows to overcome the relative discontinuity due to the grain-to-grain contact of the earth.

The whole of this retention device is, seen in plan, generally linear (one or more segments of straight). In a variant of the invention shown schematically in FIG. 2, the axis of the structure, seen from above, instead of linear, as schematized in FIGS. 2a and 2b, can receive a shape allowing, with or without impact of blocks, better combine the traction and compression efforts that the structure undergoes and better adapt to the site. A possible case is schematically illustrated in Figure 2c.

The invention can especially be applied to the retention of unstable blocks and floors, especially in hilly sites, in difficult to access sites, in sites where the supply of other materials is difficult, or in poor sites likely to support an overload.

Claims (9)

Civil engineering work, generally provided with a low density and a high compressibility, intended to receive or contain static or dynamic stresses, vertical or lateral, characterized in that it consists, at least partially, of tires arranged in bulk. Work according to claim 1 characterized in that it is, at least partially confined by one or more grids or plies or nets or prefabricated walls, or deformable or rigid, sealed or not. Work according to any one of the preceding claims, characterized in that at least two of its constituents are interconnected by one or more continuous connections, the section of which is of any shape, provided with tensile or shear resistance . Work according to claim 3 characterized in that at least one of the continuous connections is subjected to tensile or compressive stresses. Work according to claims 1 or 4 characterized in that the applied stresses are adjustable. Work according to any one of the preceding claims, characterized in that at least one of its constituents is connected without interruption by at least one bond, provided with tensile or shear strength, with at least one fixed point, resistant tensile or shear. Work according to any one of the preceding claims, characterized in that the low-density constituent is confined, at least partially, by a soil, whatever the size of the elementary particles of this soil. Work according to any one of the preceding claims, characterized by the greening of a portion of the constituents. Work according to any one of the preceding claims, characterized in that at least part of its constituents is separable into independent packets.

Images