RU2801750C1 - Method for erecting a retaining wall of a combined structure to protect coastal zones from erosion - Google Patents

Abstract

FIELD: engineering structures.

SUBSTANCE: retaining wall of the combined structure for protecting coastal zones from erosion refers to hydraulic engineering and environmental construction. In a method involving the creation of steps of layer-by-layer heavy fascias and gabion mattresses with drainage devices, according to the invention, the steps are arranged in a combined design, and for the construction of the first stage 1 and the second stage 2, heavy fascias 3 are used from bags with soil filler and a flexible shell, for which a geomat laid in 2-3 layers and tied in three places is used, and gabion mattresses 4 are made of layers of biomat 9 and perforated drainage pipes 10, laid in two lines in the middle of the biomat layers, on top of which a gabion mesh 11 is laid, providing gabion mattresses with 4 prismatic shape. On top of second step 2, on the slope, fastening from flexible mattresses 12 is provided, the filler of which is made of dense layers of geomat 6 laid along the slope of the slope. At the sole of first stage 1, along the outer row of heavy fascies 3 and the reservoir bed, flexible slabs are mounted in the form of apron 13, which are made of volumetric geogrids 14, filled with gravel and pebbles and wrapped around with a gabion mesh.

EFFECT: reliable protection of coastal zones in foothill and flat areas.

1 cl, 7 dwg

Description

The invention relates to hydraulic engineering and environmental construction and can be used in eroded riverbeds and canals to protect coastal zones from erosion. A well-known technical solution is

"Method of erecting retaining walls from gabions" (Patent RU No. 2336389) includes the manufacture and laying of gabions in the form of steps along the river bank. Gabions are placed in lattice reinforcing cages of steps. The main disadvantage of this technical solution is the need for a large amount of stone material and reinforcement, which increase the material consumption and labor intensity of the structure.

The closest technical solution is the "Method of erecting retaining walls to protect coastal zones from collapse and erosion" (Patent RU No. 2645334), including the manufacture and installation of retaining walls from two stepped heavy fascias and many stepped stacked gabion mattresses with drainage devices and flexible reinforcing soil array with grids of fiberglass materials.

The main disadvantage of this technical solution is the complexity of the design, consisting of two types of retaining walls. At the same time, for the manufacture of gabion mattresses and heavy fascines, mainly light fascines from reeds are used, which is a natural material and grows only in a water-saturated environment of flat areas, and has a limited service life. In addition, the absence of an anti-washout device at the foot of the structure, with a possible deep erosion of the channel, can lead to the collapse of retaining walls.

From the analysis of known technical solutions, it was revealed that the technical problem in this area is the need to create effective methods used to protect coastal zones from collapse and erosion.

The technical result of the proposed technical solution is to ensure reliable protection of coastal zones in the foothills and flat areas.

To solve the technical problem and achieve the claimed technical result in the method of erecting retaining walls to protect coastal zones from erosion of a combined structure, including the creation of steps from layer-by-layer heavy fascies and gabion mattresses with drainage devices, while heavy fascines are made from bags with soil filler and flexible shells, characterized in that the steps suit a combined design, for the construction of the first and second steps, heavy fascines are used from bags with soil filler and a flexible shell, while a geomat laid in 2-3 layers and tied in three places is used as a flexible shell, and gabion mattresses are made of alternating rows of biomat and perforated drainage pipes, which are placed in the middle in two lines, on top of which a gabion mesh is laid, ensuring that they are given a prismatic shape, while on top of the second step, on the slope, fastening from flexible mattresses is provided, the filler of which is made of dense layers of geomats laid along the slope of the slope, and at the foot of the first step, along the outer row of heavy fascies and the bed of the reservoir, flexible plates in the form of an apron are mounted, which are made of volumetric geogrids, filled with gravel and pebbles and wrapped around with a gabion mesh.

The erected retaining walls simultaneously perform the functions of a protective structure and drainage devices, providing reliable protection of the coastal slope from collapse, and safe drainage of ground and surface waters.

The invention is illustrated in the drawings.

In FIG. 1 shows a cross section of a two-stage retaining wall shoreline;

in fig. 2 - plan of the coastal anchoring site;

in fig. 3 - heavy fascine with a slit;

in fig. 4 - gabion mattress with drainage pipes;

in fig. 5 shows a geomat;

in fig. 6 shows a biomat;

in fig. 7 - volumetric geogrid.

The retaining walls of the combined design consist of two stages - the first stage 1 and the second stage 2, which are made of heavy fascias 3 and gabion mattresses 4. Heavy fascias 3 consist of filler and flexible shell; the filler is made entirely of interconnected bags 5 filled with local (vegetative) soil; and the shell is made of two or three layers of geomat 6 and flexible gabion mesh 7. Mounting loops 8 are provided in the places of dressing of heavy fascies 3. Gabion mattresses 4 consist of layers of biomat 9, drainage perforated pipes 10 (laid in two lines in the middle of the layers of biomat 9) and gabion mesh 11. On the coastal slope above the second stage, a fastening of flexible mattresses 12 is provided, the filler of which is used geomats 6, laid in layers and wrapped in a geogrid. At the foot of the first stage 1, along the rows of heavy fascies 3 and the riverbed, flexible slabs are arranged in the form of an apron 13, consisting of volumetric geogrids 14 filled with gravel and pebbles and wrapped around in a gabion mesh 15.

An example of the implementation of the method.

Retaining walls of the combined design are carried out and work as follows.

Construction is carried out in sections and the number of sections for the construction of retaining walls can be one, two or more. First, the first section of the coastal zone is being built; for this, a site is planned along the riverbed. And all elements of retaining wall fastenings are made mainly on site using mechanical fixtures and construction equipment. First, the required volume of materials is prepared: drainage perforated pipes, geomat, biomat, gabion nets, geogrids and geogrids. They are cut according to the size of heavy fascines 3, gabion mattresses 4, flexible mattresses 12 and the length of flexible plates (apron 13). Next, the required number of bags 5 filled with local (preferably vegetable) soil is made, and on their basis heavy fascines 3, gabion mattresses 4, flexible mattresses 12 and an apron 13 from flexible plates. The building products made in this way are stacked along the coastal fastening near the places of their installation. After that, a site is developed and planned along the coast along the width of the retaining walls and taking into account the length of gabion mattresses 4 and apron 13, and taking into account their stepped arrangement. The site is divided into sections, and the installation is carried out in sections. To do this, along the line of the first stage, the first two rows of heavy fascines 3 are laid out in length so that their mesh shells (gabion meshes 7) are in contact, and at the points of their contact they are connected with galvanized metal wire (diameter 1.5-2 mm). Then, from the inside, behind the rows of fascines 3, the local soil is filled in and leveled with compaction to the mark of the top of the fascias. On top of two rows of fascias 3 with a tie-in into the slope, gabion mattresses 4 of the first stage 1 are mounted. And on top of the first stage (stepping back to the width of the step), one longitudinal row of heavy fascias 3 is mounted with their mesh shells connected and attached to the gabion mattresses of the first stage using galvanized metal wire. After that, from the inside, behind the longitudinal row of fascies 3, the local soil is filled up and leveled with compaction to the mark of the top of the fascias. Gabion mattresses 4 of the second stage 2 are mounted above and across the longitudinal row of fascias 3 with a tie-in into the slope. Then, flexible mattresses 12 are mounted on top of the second step on the slope. After that, at the sole of the first step 1 along (close) the outer row of heavy fascias 3, flexible plates of the apron 13 are mounted. gravel and pebbles. Then, around the geogrids filled with gravel and jackdaws, a gabion mesh is fitted with the connection of the bottom and upper layers of the mesh and attaching 7 heavy fascines 3 of the first stage 1 to the meshes.

In the same way, retaining walls of a combined structure are erected in other parts of the coastal zone. All the main steps of coastal fastening are erected to the top of the eroded soil massif (up to marks not less than 1 m above the level of high waters). In this case, gabion mattresses 4 must be cut into the slope horizontally or with a slight slope not exceeding 0.0001. The dimensions of heavy fascines, gabion and flexible mattresses and the strength of their mesh shells are taken depending on the current (possible) maximum hydrodynamic loads of flood flows of calculated security. The most effective from the point of view of the construction technology and the reliability of the operation of retaining walls are: heavy fascines 2.0-2.4 m long and 0.4-0.6 m in diameter, and gabion mattresses - 2.5-3.0 m long and 0.3-0.4 m thick. In the same way, they take the dimensions of a flexible slab arranged as an apron 13, and the types of geogrids used in this case, the height and dimensions of their cells, as well as the gabion mesh 15. The length of the apron 13 towards the channel of the river L should be, L>1.5h _p , where h _p is the maximum depth of possible erosion of the riverbed below the base of the apron. With the maximum possible erosion of the channel, the apron will lie along the line of repose and prevent further spread of erosion towards the retaining walls. This ensures the stability and reliability of the retaining walls.

Retaining walls have a high degree of flexibility and water permeability, they work as protective retaining walls and as drainage. The main hydrodynamic loads of flood flows are perceived by gabion and flexible mattresses 4, 12, and anti-washout plates of the apron 13, and provide stability to coastal slopes. In the construction, due to the fact that the gabion mattresses 4 are made of a flexible design with drainage devices and cut into the soil slope, their joint work is ensured to retain the soil mass. It also provides a complete interception and safe removal of the soil filtration flow by the drainage devices of the mattresses 4 (including surface runoff flowing down from the coastal slope). In addition, the flexible apron 13 provided at the foot of the structure, loaded inside (geogrids) with gravel and pebbles, prevents the channel from being washed away at the foot of the structure and the shift of the coastal attachment with the soil massif.

The use of geomats and biomats in gabion and flexible mattresses not only increases the water permeability and flexibility of the structure, but also helps to retain moisture in the body of the structure for a long time. This creates good conditions for the germination of grasses and shrubs on the slopes of the structure. Biomats and geomats are environmentally friendly artificial materials that do not interfere with the natural environment.

Thus, the retaining walls of the combined structure, erected by the proposed method, provide reliable protection for coastal zones in their foothill and flat areas, where erosion of the channel and collapse of soil slopes are possible, while they will turn into environmental structures that help the development of nature and are included in the ecosystem of the territory .

The proposed method of erecting retaining walls of a combined design can most effectively be used for engineering protection of coastal zones from possible erosion and collapse in flat and foothill, hard-to-reach areas of small rivers.

Claims (1)

A method for erecting a retaining wall of a combined structure to protect coastal zones from erosion, including the creation of steps from layer-by-layer heavy fascias and gabion mattresses with drainage devices, while heavy fascias are made from bags with soil filler and flexible shells, characterized in that the steps suit a combined design , for the construction of the first and second stages, heavy fascines are used from bags with soil filler and a flexible shell, while a geomat is used as a flexible shell, laid in 2-3 layers and tied in three places, and gabion mattresses are made from layers of biomat, drainage perforated pipes laid in two lines in the middle of the biomat layers, and a gabion mesh laid on top, providing gabion mattresses with a prismatic shape, while on top of the second step, on the slope, fastening from flexible mattresses is provided, the filler of which is made of dense layers of geomat, laid along the slope of the slope , at the sole of the first stage and along the outer row of heavy fascies and the bed of the reservoir, flexible plates in the form of an apron are mounted, which are made of volumetric geogrids, filled with gravel and pebbles and wrapped around with a gabion mesh.