RU2801714C1 - Retaining wall of reinforced soil structure to protect coastal zones from collapse and erosion - Google Patents

Abstract

FIELD: engineering structures.

SUBSTANCE: retaining wall of the reinforced soil structure for protecting coastal zones from collapse and erosion refers to hydraulic engineering and environmental construction. The retaining wall comprises step-laid gabion mattresses 1 with drainage devices and flexible reinforcing soil mass elements located one above the other and cut, in a stepped manner, into the collapsible soil mass of the slope along its entire height, while passing beyond the line of possible collapse of the earth mass; according to the invention, the flexible reinforcing elements are made in the form of slabs 5, consisting of a fibreglass mesh and volumetric geogrids, and attached to the base of step-laid gabion mattresses 1, and gabion mattresses 1 are made of perforated drainage pipes, geomat and gabion mesh, which provides them with a prismatic shape. Flexible plate 5 of the first row 8 of gabion mattresses 1 is located on the outside along the channel part of the reservoir in the form of apron 9. Remaining slabs 5, starting from the fourth row of gabion mattresses 1, are cut in steps into the collapsed soil mass of the slope along its entire height. Gabion mattresses 1 of the second and third rows are made without reinforcing plates 5.

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

1 cl, 5 dwg

Description

The invention relates to hydraulic engineering and environmental construction and can be used to protect coastal zones from collapse and erosion.

Known construction, made of gabion retaining walls (patent RU No. 2449081) including gabions laid in the form of steps along the river bank. Gabions are placed in lattice reinforcing cages, which are pre-made according to the dimensions of the step section. The disadvantages of this technical solution are the complexity of the design and the need for a large amount of stone material.

A similar technical solution is the device presented in the "Method of erecting retaining walls to protect coastal zones from collapse and erosion" (patent RU No. 2645334). The retaining wall consists of two layered heavy fascies and gabion mattresses with drainage devices and flexible fiberglass mesh reinforcing the soil mass.

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 has a limited service life. In addition, fiberglass meshes reinforcing the soil mass do not create sufficient resistance forces to hold the collapsed mass, especially when the mass consists of clay soils.

From the analysis of known technical solutions, it was revealed that the technical problem in this area is the need to expand the arsenal of tools 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, the retaining walls of the reinforced soil structure for protecting coastal zones from collapse and erosion, containing step-laid gabion mattresses with drainage devices and flexible reinforcing soil mass elements located one above the other and stepped cut into the collapsible soil mass of the slope along its entire height, with the passage further of the line of possible collapse of the earthen mass, in which flexible reinforcing elements, made in the form of plates, made of fiberglass mesh and volumetric geogrids, are attached to the base of stepwise laid gabion mattresses, while gabion mattresses are made of alternating rows of geomats and perforated drainage pipes passing in the middle in two lines, with a gabion mesh laid on top of them, providing them with a prismatic shape, while the flexible slab of the first row of gabion mattresses is located on the outside along the channel part of the reservoir in the form of an apron, and the rest, except for the second and third rows, stepwise cut into the collapsed soil mass of the slope along its entire height.

The device is shown in the drawings:

in fig. 1 shows a cross-section of a gabion mattress shoreline with reinforcing flexible slabs;

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

in fig. 3 - gabion mattress with a flexible plate reinforcing the soil mass;

in fig. 4 shows a geomat;

in fig. 5 - volumetric geogrid.

The retaining walls of the reinforced soil structure consist of multi-stepped gabion mattresses 1, made of drainage perforated pipes 2, geomat 3 and gabion mesh 4. Flexible reinforcing plates 5 are attached to the base of the gabion mattresses 1, consisting of fiberglass mesh 6 and volumetric geogrids 7. To the base of the first row 8 of gabion mattresses, a flexible slab is attached with an outward direction in the form of an apron 9 arranged along the river bed and loaded with gravel and pebbles from above.

Retaining walls of the reinforced soil structure from flexible mattresses and plates are erected 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 erected; 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, gabion nets, fiberglass nets and geogrids. They are cut according to the size of the gabion mattresses 1 and the length of the reinforcing flexible plates 5. Next, the required number of gabion mattresses 1 and reinforcing flexible plates 5 are made. The gabion mattresses 1 and flexible plates 5 made in this way are folded along the coastal attachment near their installation sites. 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 the flexible plates 5 and their stepped arrangement. The site is divided into sections, and the installation is carried out in sections. To do this, flexible reinforcing plates 5 are attached to most gabion mattresses 1 (except for the second and third rows) using galvanized wire. Then, along the length of the first section, the first row of 8 gabion mattresses 1 with flexible plates 5 is laid out in length, forming an apron 9 along the riverbed. And on top of the apron 9, geogrids 7 are loaded with gravel and pebbles to protect the structure (retaining walls) from being washed away from the riverbed. Behind the first row of 8 gabion mattresses, local soil is poured from the inside and leveled with compaction to the mark of the top of the mattresses 1. Further, on top of the first row of 8 gabion mattresses (stepping back to the width of the first step, equal to half the width of the mattress 1), gabion mattresses of the second and third rows are mounted stepwise ( without reinforcing plates). At the same time, local soil is poured behind the gabion mattresses from the inside with compaction and leveling to the level mark of the top of the mattresses of the third row. After that, the installation of gabion mattresses 1 of the fourth and subsequent rows with flexible reinforcing plates 5 begins. On top of the third row of gabion mattresses 1 and the ground area behind it (stepping back to the width of the step), the fourth row of mattresses 1 is mounted and laid out together with flexible plates 5 attached to them. Then geogrids 7 flexible plates 5 are covered from above with local soil with compaction and leveling up to the mark of the top of the mattresses of the fourth row. In the same way, the remaining rows of retaining walls are erected up to the uppermost of the gabion mattresses 1 with flexible reinforcing plates 5. In all rows of retaining walls, gabion mattresses 1 and flexible plates 5 are interconnected by galvanized metal wire (diameter 1.5-2.5 mm).

Thus, retaining walls are also built in other parts of the coastal zone, all the main layers (steps) of the coastal fastening are erected to the top of the collapsing soil massif (up to marks at least 1 m above the high water level). In this case, flexible reinforcing plates 5 must be cut into the slope horizontally or with a slight slope not exceeding 0.0001. The dimensions and thickness of the flexible reinforcing plates 5 (including the dimensions of the cells) and the strength of their design depend on the accepted types of volumetric geogrids 7 and fiberglass meshes attached to them. They are taken depending on the power of the collapsed slope and the possible maximum tensile forces arising from the shift of earth masses. And the dimensions of the flexible slab, arranged as an apron 9 along the riverbed, are taken depending on the possible maximum depth of erosion of the channel at the foot of the structure. The length of the apron 9 in the direction of the riverbed L should be, L>l,5h _p , where h _p is the maximum depth of possible erosion of the riverbed below the base of the apron.

Retaining walls of the reinforced soil structure made of flexible mattresses and slabs work as follows.

The retaining walls of the reinforced soil structure have a high degree of flexibility and water permeability, and work in this way. The main hydrodynamic loads of the soil massif and the filtration flow of water are perceived by gabion mattresses 1 with reinforcing elements 5, 6 and 7, stepped into the slope.

In the construction, due to the fact that the gabion mattresses 1 are made of a flexible design with drainage devices and flexible plates reinforcing the soil, their joint work with the soil mass in the form of a reinforced soil structure is ensured, which ensures the stability of the collapsing slope, as well as the interception and removal of the seepage flow from the coastal soil array. As a result, in the area of the surface of the possible collapse of the soil mass and along the flexible reinforcing plates 5, the necessary cohesive and friction forces of the soil are formed, reliably holding the soil mass from possible slipping or collapse. Due to the use of volumetric geogrids 7 attached to grids 6 (made of fiberglass) and gabion mattresses 1, the holding forces increase by more than 2 times compared to the shear forces of the soil mass. In addition, the flexible apron 9 provided at the foot of the structure, loaded from above with gravel and pebbles, prevents the channel from being washed away at the foot of the structure and the shift of the slope attachment (retaining wall) with the soil mass. It also provides complete interception and safe removal of soil filtration flow by drainage devices of mattresses 1 (including surface runoff flowing down from the coastal slope). Here, gabion mattresses 1 with reinforcing slabs 5 play the role of protective fasteners, retaining walls and drainage devices that work together to hold the soil mass and safely drain river and ground water flows.

The use of geomats in gabion 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. Geomats are environmentally friendly artificial materials that do not interfere with the natural environment.

Retaining walls made of flexible mattresses and slabs can be most effectively used for engineering protection of coastal zones from possible collapse and erosion in flat and foothill, hard-to-reach areas, when the height of the coastal collapse slope does not exceed 10-15 meters.

Thus, the proposed retaining walls of the reinforced soil structure, in comparison with the prototype, 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 turn on into the ecosystem of the area.

Claims (1)

A retaining wall of a reinforced soil structure for protecting coastal zones from collapse and erosion, containing stepped-laid gabion mattresses with drainage devices and flexible reinforcing soil mass elements located one above the other and stepped cut into the collapsing soil mass of the slope along its entire height, with passing beyond the line of possible earth mass collapse, characterized in that the flexible reinforcing elements are made in the form of plates, consisting of a fiberglass mesh and volumetric geogrids, and attached to the base of stepped gabion mattresses, moreover, gabion mattresses are made of perforated drainage pipes, geomat and gabion mesh, which provides them with prismatic shape, while the flexible slab of the first row of gabion mattresses is located on the outside along the channel part of the reservoir in the form of an apron, and the rest of the slabs, starting from the fourth row of gabion mattresses, are stepwise cut into the collapsing soil mass of the slope along its entire height, the gabion mattresses of the second and the third row are made without reinforcing plates.