RU2585302C1 - Road structure on weak base for roads - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction and can be used in construction, reconstruction and repair of motor roads on weak heaving soils. Road structure on weak base for motor roads includes upper working layer of fill and fill body equipped with reinforcing elements. Upper working layer of fill is made with thickness of 1.1…1.2 m, and body of fill is made from alternating layers of bulk non-heaving soil and webs of metal system, at edges connected with volumetric framed structures of box type, filled with rock soil with stone size of not less than 70 mm.

EFFECT: technical result consists in improvement of resistance and stability of earthwork structure on weak base at seasonal deformation under unequal action of forces of frost heaving and precipitation during thawing, high strength, rigidity and stability of structure.

3 cl, 2 dwg

Description

The invention relates to the field of construction and can be used in the construction, reconstruction and repair of roads on weak heaving soils.

One of the reasons for the loss of the bearing capacity of structures is their non-uniform seasonal deformations arising from heaving and subsidence of the soil of the base. As a result of freezing of the water contained in the soil of the subgrade, it swells, and during spring thawing - sediment as a result of softening. It is impossible to exclude seasonal deformations of the subgrade, therefore, the main tasks are to weaken the action of frost heaving or to ensure the uniformity of seasonal deformation.

Structural and technological solutions are known from the existing state of the art, which consist of replacing structurally unstable base soil with non-porous materials, arranging soil piles at the base, etc. (Road design: Reference road builder encyclopedia (EDMS), T. 5. / Ed. G.A. Fedotova, P.I. Pospelova, Moscow: Informavtodor, 2007).

A disadvantage of the known solutions is a significant increase in the volume of earthwork, the complex technology of the work, and, accordingly, the high cost.

The most widespread, in order to increase the stability of earthworks on weak grounds, were methods of reinforcing them with geosynthetic materials based on polypropylene and polyethylene.

Closest to the claimed technical solution is the reinforcement of the embankment on a weak base with geosynthetic materials (see Recommendations on the use of geosynthetic materials in the construction and repair of roads (instead of VSN 49-86). - M .: FSUE Informavtodor, 2003). To ensure uniform precipitation and to achieve an additional reinforcing effect by increasing the rigidity of the lower part of the embankment, geosynthetic interlayers are arranged in several layers with the conclusion of the lower part of the embankment in a “clip”. As geosynthetic materials use geogrids and geogrids based on polypropylene or polyester.

The disadvantages of this technical solution are the susceptibility of polymeric materials to mechanical abrasion upon contact with soil particles, insufficient chemical resistance to aggressive media, and especially their creep, which significantly reduces the resistance of the armored structure to the uneven effects of frost heaving forces.

The technical result of the claimed invention is to increase the resistance and stability of the structure of the earthworks on a weak base during seasonal deformation under the unequal influence of the forces of frost heaving and precipitation during thawing.

The result is achieved in that an earthen structure on a weak base for roads, containing the upper working layer of the embankment and the body of the embankment provided with reinforcing elements, is characterized in that the upper working layer of the embankment is made with a thickness of 1.1 ... 1.2 m, and the body of the embankment is made from alternating layers of loose non-porous soil and canvases of a metal geogrid, connected at the edges to volumetric box-type lattice structures filled with rocky soil with stone sizes of at least 70 mm.

An earth structure is also characterized in that the volumetric lattice structures are made with a rectangular or trapezoidal cross section, depending on the steepness of the slopes of the earth structure.

An earthen structure is also characterized in that at an embankment height of more than 3 m, volumetric lattice structures are installed in two rows at a distance of at least 1 m from the edge of the lower layer of bulk soil made with a thickness of at least 0.6 m.

The claimed earthworks on a weak base for roads is distinguished by the fact that under the bottom of the working layer of the embankment at a depth of 1.1 ... 1.2 m there is a dividing armored soil element made up of alternating layers of loose non-porous soil and metal geogrid blades, connected at the edges with voluminous lattice structures box-type, filled with rocky soil with stone sizes of less than 70 mm. In this case, the volumetric lattice structure can be made of rectangular or trapezoidal cross-section, depending on the steepness of the slopes of the earthen structure. Volumetric lattice structures can be located at one level with an embankment height of up to 3 m (Fig. 1) and in two levels with an embankment height of more than 3 m (Fig. 2). The metal mesh is attached to the volumetric lattice structures by wire and forms a closed loop, increasing the strength and stability of the structure.

The basis of the invention is the ability of layers of metal mesh to perceive and redistribute loads from deeps and sediments, which significantly reduces or completely counteracts the uneven deformation of the subgrade.

The advantage of the invention is the erection of an earth structure, the stability of which is ensured by eliminating uneven sediments and abysses of a weak base due to perception, redistribution of loads by layers of a metal mesh with their transfer to bulk lattice structures during operation.

In FIG. 1 shows a diagram of an earthen structure up to 3 m high on a weak heaving foundation, in FIG. 2 is a diagram of an earthen structure with a height of more than 3 m on a weak heaving foundation.

In the drawings:

1 - volumetric metal lattice structures filled with rocky soil with stone sizes of at least 70 mm;

2 - metal geogrid;

3 - a working layer of bulk soil with a thickness of 1.1 ... 1.2 m;

4 - a layer of bulk non-porous soil;

5 - a layer of bulk soil with a thickness of at least 0.6 m;

6 - the base of the "weak" heaving soil.

The construction of an earthen structure is as follows:

On the profiled surface of the layer of bulk soil 5, with a thickness of at least 0.6 m, in the lower part of the embankment, volumetric metal box-type lattice structures are installed. They can be a trapezoidal cross section 0.5 m high or a rectangular cross section 0.5 m or 1 m high. Inside the volumetric metal lattice structures are filled with rocky soil. The size of the stones must be at least 70 mm. With embankment heights of up to 3 m, volumetric lattice structures of trapezoidal section are placed in one row. When the embankment height is more than 3 m, rectangular structures with a height of 0.5 m or 1 m are used, which are installed in two rows. In this case, the distance from the edges of the gabion installation to the edge of the lower embankment layer is 1 m. For drainage of surface waters, the surface of the lower embankment layer is given a transverse slope away from bulk metal lattice structures of 40 ... 50 ‰. As volumetric lattice structures, for example, the gabions of the Terrames system are used. They are a prefabricated volumetric box construction made of double torsion metal mesh with hexagonal cells, divided into sections by means of diaphragms installed inside the gabion every meter in length.

The space between the volumetric metal lattice structures is filled with alternating layers of bulk non-porous soil 4 and metal geogrid 2. The metal grid is attached to the volumetric metal lattice structures using galvanized steel wire. Laying of rolls of a metal geogrid is carried out in the longitudinal direction with the help of a rolling material roll. The tension and fastening of the geogrid rolls between each other is carried out manually. As a metal geogrid, it is recommended, for example, a Rodmesh brand mesh made of double-twisted steel wire with zinc coating, reinforced with a reinforcing bar located in the transverse direction. With its high strength, the Rodmesh geogrid is ideal for reducing the deformation of an earth structure.

Laying a layer of loose non-porous soil 4 is a mechanized method.

The working layer of bulk soil 3 is arranged mechanically to a thickness of 1.1 ... 1.2 m, sufficient for the unhindered installation of technical means for organizing traffic.

During operation, a metal geogrid perceives loads from uneven deformation of a weak base. Due to the fixing of the mesh to the volumetric lattice structures that remain stationary as the forces are redistributed and transferred from the lower row of the geogrid through the layer of bulk non-porous soil to the upper row of the geogrid, strain attenuation occurs and the working layer of the embankment remains stable. In turn, the anchoring of volumetric lattice structures with a metal geogrid prevents their creep under the action of loads. A similar process is observed during the upsetting of a weak base during the thawing period.

The proposed earthworks on a weak heaving base have the following advantages:

1. Significant or complete elimination of uneven deformations from sediments and deeps of a weak heaving base;

2. The widespread use of materials;

3. An increase in the strength, rigidity and stability of the structure through the use of a metal mesh connected to gabions;

4. The durability and stability of the claimed design is much higher than similar due to the use of metal mesh and volumetric lattice structures;

5. The construction of an earthen structure does not require special equipment.

Claims (3)

1. An earthworks on a weak base for roads, containing the upper working layer of the embankment and the body of the embankment, equipped with reinforcing elements, characterized in that the upper working layer of the embankment is made with a thickness of 1.1 ... 1.2 m, and the body of the embankment is made of alternating layers loose non-porous soil and canvases of a metal geogrid, connected at the edges to volumetric box-type lattice structures filled with rocky soil with stone sizes of at least 70 mm. 2. An earth structure according to claim 1, characterized in that the volumetric lattice structures are made with a rectangular or trapezoidal cross-section, depending on the steepness of the slopes of the earth structure. 3. An earthen building according to claim 1, characterized in that at an embankment height of more than 3 m, volumetric lattice structures are installed in two rows at a distance of at least 1 m from the edge of the lower layer of bulk soil made with a thickness of at least 0.6 m.

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