RU2499866C1 - Method to raise water level in small watercourses after dredging works (versions) - Google Patents

Abstract

FIELD: construction.SUBSTANCE: method to raise a water level in small watercourses after dredging works includes erection of a retaining dam upon completion of dredging works. The main dam body is created from soil. At least one flexible concrete mat is arranged in the outer part of the dam. The height of dam is by 10÷80% less than the height of the dredged riverbed wall. The second version of the method includes erection of a cascade of retaining dam. The second dam of the cascade is erected by 0.1÷0.3 m below at the elevation from the sea level. To erect a retaining dam, dredging works are carried out in separate sections of the riverbed. The distance between sections is selected as equal to the width of the main dam body. Then the height of the main dam body is adjusted, and it is coated with a flexible concrete mat. The retaining dam comprises the main body. The outer part of the dam comprises at least one flexible protective mat. The flexible concrete mat comprises concrete blocks connected to each other row-by-row and within with a gap by flexible elements. The mat comprises an anti-suffosion element and/or elements for complete closure of gaps between all concrete blocks or between their part. The width of gaps between at least 75% of the blocks in the mat makes from 1 mm to 25 mm in the length of at least 80% of the dimensional length of blocks adjacent to each other. Concrete blocks have height from 50 mm to 350 mm.EFFECT: raising water level in small watercourses after dredging works, simplified dam design, increased manufacturability of its creation, high extent of protection of a soil main body of the dam.22 cl, 8 dwg

Description

The technical solution relates to hydraulic structures, namely to dams for raising the water level.

This technical solution can be used after dredging on small streams, in particular streams.

Small streams are usually subject to siltation. As a result of a gradual increase in the thickness of the layer of silt sediments, the bottom level of the small watercourse rises and there is flooding, characterized by an increase in the level of groundwater in the area, which leads to disruption of economic activity, land degradation, change in the conditions of plant growth and animal habitat. In particular, the coast swamps, water enters the cellars and cellars, which interferes with their operation and gradually leads to the destruction of buildings. In this area of the territory there may be a risk of flooding.

To eliminate this phenomenon at small streams, dredging is carried out to reduce water.

For example, bottom sediments with a depth of about 2 m are removed in the channel of the stream, the usual depth of which is about 0.5 m.It is not practical to deepen the channel with powerful technical means, since a slight deepening of the channel will soon require a repeat of this operation. As a result of dredging, the water level in the stream drops significantly, and the depth of the stream becomes even less, since the inflow (debit) of water has remained the same, and the width of the stream has been increased for technological reasons. Often, after dredging at the bottom of a trench (channel) with a depth of 2-3 m, a relatively shallow stream flows.

The excessive deepening of the bed of small streams caused by technological necessity has undesirable environmental consequences, including, among other things, a decrease in soil fertility, as well as the impossibility of the natural movement of many animal species in this territory. There is a danger of injury and death of people and animals when falling into a deep trench. Water intake from a small watercourse for household purposes is difficult. The landscape is losing its aesthetics.

Depending on the dredging technology used, not only bottom sediments are removed, but also the underlying soil is selected, creating a trench up to 4-5 m deep, which only exacerbates the situation.

The objective of this technical solution is to restore a small watercourse after dredging.

The problem is solved by creating a retaining dam or cascade of dams, that is, a water-supporting structure, blocking the watercourse to raise the water level. Sub-heading refers to a rise in water level resulting from the blockage of a watercourse channel.

For this application, blank dams, that is, dams in which there are no devices for passing water, may be best suited, as it is sufficient to ensure the overflow of water through the crest of the dam. Moreover, in this case, it is advisable to use soil dams, the main body of which is made of soil materials, due to the simplicity of their construction.

In the prior art (patent document SU 1094891 A), a retaining structure is known, including a soil embankment and a cladding in the form of a plurality of plates interconnected by elastic rods, in which the joints of the plates are equipped with elastic waterproof gaskets.

However, the construction of a known retaining structure is characterized by high complexity for its use as a means for raising the water level in small streams.

A flexible concrete mat (GBM) is known from patent document RU 106629 U1, which is intended, in particular, to protect crests of dams and dams from erosion during overflow. Known GBM contains concrete blocks, interconnected in order and in rows with a gap by flexible elements in the form of ropes. Also known GBM contains elements for the partial overlap of the gaps between concrete blocks, made in the form of a border, which is a protruding belt of cured cement-sand mixture in the perimeter of the largest cross section of the concrete block. When a well-known GBM is bent, the edging of adjacent blocks touches and crashes.

However, in practice, partial overlapping of gaps between concrete blocks is not always able to prevent soil leaching from the main body of the dam.

The technical result provided by the present invention is to provide a simple rise in the water level in small streams after dredging, to simplify the design of the dam, increase the manufacturability of its creation, reduce the number of imported materials and eliminate the use of technically complex elements while ensuring a high degree of protection of the ground main body of the dam.

The technical result is achieved due to the fact that in the first embodiment, the method of raising the water level in small streams after dredging involves the construction of a retaining dam after dredging is completed in this section of the watercourse. Moreover, they create the main body of the dam from the soil. At least one GBM is placed in the outer part of the dam. The height of the dam is 10–80% less than the height of the wall of the in-depth channel.

In the particular case of the implementation of the method, prior to placing the GBM, an anti-suffusion device is placed on the main body of the dam. Also, in a particular case, a reinforcing mesh is laid on the anti-suffusion device.

In another particular case, the main body of the dam is created from local soil.

In the second version of the method of raising the water level in small streams after dredging, a cascade of retaining dams is erected. Moreover, after dredging is completed, the main body of the first retaining dam from the soil is created in this section of the watercourse. At least one GBM is placed in the outer part of this dam. Then, a second retaining dam of the same design is erected 0.1–0.3 m below the mark from sea level.

In the particular case of this method, after the construction of the second dam throughout the entire channel of the watercourse, the next retaining dams are erected, located from each other at a distance of 0.1 ÷ 0.3 m below the mark from sea level.

Also, in the particular case, immediately before placing the GBM, an anti-suffusion geotextile and a reinforcing mesh are successively laid on the dam body.

Also, the technical result is achieved by the fact that in the method of erecting a retaining dam for raising the water level in small streams after dredging, dredging is carried out in separate sections of the channel. Moreover, the distance between these sections is chosen equal to the width of the main body of the dam. Then adjust the height of the main body of the dam and cover it with GBM.

In addition, the technical result is achieved in that the retaining dam for raising the water level in small streams after dredging contains the main body. The outer part of the dam contains at least one GBM. Moreover, the maximum height of the dam is 10 ÷ 80% less than the height of the wall of the channel of the watercourse after it is deepened.

In a particular case, the main body of the dam is made in whole or in part from soil materials.

In another particular case, the height of the dam is from 1.5 m to 2.5 m.

In another particular case of the execution of the dam, the GBM contains elements for completely overlapping the gaps between all concrete blocks or between their parts.

Also in the particular case, the width of the gaps between at least 75% of the blocks in the GBM is from 1 mm to 25 mm for at least 80% of the overall length of the adjacent concrete blocks.

In another particular case, under the GBM, an anti-suffusion element is laid on the main body of the dam.

In a particular case, a reinforcing mesh is placed between the anti-suffusion element and the GBM.

Also in the particular case, the GBM contains an anti-suffusion element.

In another particular case, the anti-suffusion element is a geotextile web.

The technical result is also achieved by the fact that the GBM, containing concrete blocks connected in order and in rows with a gap by flexible elements, contains an anti-suffusion element and / or elements for completely overlapping gaps between all concrete blocks or between their part. Moreover, the width of the gaps between at least 75% of the blocks in the GBM is from 1 mm to 25 mm for at least 80% of the overall length of adjacent blocks, and concrete blocks have a height of 50 mm to 350 mm.

In the particular case of performing GBM, the anti-suffusion element is a geotextile web.

In another particular case, the elements for complete overlap of the gaps between the concrete blocks are flexible plates or strips.

Also in the particular case, the elements for the complete overlap of the gaps between the concrete blocks are made in the form of solid plates or blocks.

In another particular case, the flexible elements connecting the concrete blocks are ropes.

The invention is illustrated by the following graphic materials.

Figure 1 schematically shows the axis of the dam in cross section.

Figure 2 shows a top view of the bottom, front and General top view of the GBM.

Figure 3 presents a longitudinal section of the channel of the watercourse after one of the options for dredging.

Figures 4 and 5 show a front view of a peripheral fragment of GBM and a top view of a pair of concrete blocks of GBM, explaining characteristic values.

Figure 6 shows the front and top views of a fragment of the GBM with anti-suffusion element.

Figure 7 presents a front and top view of a fragment of the GBM with elements for complete overlap of the gaps between the concrete blocks in the form of flexible strips.

On Fig shows a front and top view of a fragment of the GBM with elements for the complete overlap of the gaps between the concrete blocks in the form of rigid plates.

After dredging, the bottom of the 2 channel 1 is significantly lower relative to the coastline 3 of the channel 1 compared to its initial level 4.

A retaining dam is designed to raise the water level in small streams after dredging, which creates a rise in the water level in channel 1, which is manifested in the excess of the upper pool 5 above the level of the lower pool 6. To raise the water level in the vast majority of small streams, it is advisable to use retaining dams with with a maximum height of 1.5 m to 2.5 m or with a maximum dam height of 10 ÷ 80% less than the height of the wall of the channel of the watercourse after it is deepened. The maximum dam height refers to the vertical distance from the crest mark to the lowest mark of the dam base, that is, to the bottom of the channel of the watercourse after dredging.

Raising the water level in channel 1 of small watercourses is most simple with the help of earthen dams, that is, dams, the main body of which consists of soil, which ensures the stability and strength of these dams.

The main body 7 of the dam is preferably made from local soils.

It is permissible to create the main body 7 of the dam partly from sandy or clay soils, and partly from coarse clastic soils. In this case, a stone-earthen dam is obtained.

A flexible anti-suffusion element 8 is laid on the main body 7 of the dam, for example, a geotextile fabric with anti-suffusion properties or a polymer film. The anti-suffusion element 8 prevents the leaching of soil from the main body 7 of the dam, and therefore prevents its destruction.

Commercially available flexible anti-suffusion materials do not have high mechanical strength, which is why it is advisable to cover them with protective agents on top. In the particular case of the present technical solution, the anti-suffusion element 8 is covered with a reinforcing mesh 9, for example, made of steel wire with an anti-corrosion coating, and at least one GBM 10, which performs the function of attaching the upper and lower slopes of the earthen dam. The reinforcing mesh 9 protects the anti-suffusion element 8 from damage by the sharp corners of the GBM 10.

However, the GBM 10 even without the anti-suffusion element 8 is able to exert a significant protective effect, preventing the erosion of the main body 7 of the dam. Protection implemented exclusively by GBM 10 is especially effective in the case of creating the main body 7 of the dam from clay soils and / or in the absence of a strong current in this section of a small watercourse.

The gap between the concrete blocks 11 GBM 10, connected by flexible elements 12, in particular, ropes, cables or chains, has a value h (figure 4), component from 1 mm to 25 mm A minimum clearance is necessary to ensure the mobility of adjacent concrete blocks 11 relative to each other, as well as in the absence of an anti-suffusion element 8 or elements covering the gap between the concrete blocks 11 (Figs. 7 and 8). If the indicated elements are used in the dam design, then the distance between the concrete blocks 11 can be increased up to 25 mm. An increase in the distance between the concrete blocks 11 GBM 10 more than 25 mm is undesirable, since the anti-suffusion element 8 is not sufficiently protected from mechanical damage, for example, from floating objects, and the elements that close the gap between the concrete blocks 11 will need to be increased in size, which will complicate the design and installation of GBM 10.

The technical result is achieved only if the gap width h is maintained on a relatively large portion S between adjacent blocks 11 (in FIG. 5, the distance between the concrete blocks 11 is increased for clarity). It was experimentally established that the length of the section S between adjacent blocks 11 should be at least 80% of the overall length (width) W of adjacent blocks 11. Otherwise, the flexibility of the GBM 10 will be impaired, or its protective characteristics will decrease. The length of the section S is less than or equal to the overall length W of the concrete block 11. The difference between the values of W and S can be caused, for example, by rounding the edges of the concrete blocks 11, when performing their pyramidal or similar shape. These conditions must be satisfied for at least 75% of blocks 11 in GBM 10, since otherwise GBM 10 as a whole will not have the required properties and the technical result will not be achieved.

In Fig.1 GBM 10 is shown schematically, the distance between the concrete blocks is increased. In fact, the gap between the concrete blocks is significantly smaller, and the upper pool 5 practically coincides with the crest of the dam, through which the water is overfilled.

GBM 10, as well as an anti-suffusion element 8 and a reinforcing mesh 9, if present in the dam structure, form its outer part.

The rise of the water level in small streams after dredging is as follows.

After dredging is completed, a retaining dam is erected in this section of the watercourse. At the same time, mechanized means create a bulk or alluvial main body 7 of the dam, such that the maximum dam height is 10 ÷ 80% less than the wall height of the in-depth channel 1. At least one GBM 10 containing concrete blocks 11. GBM is placed in the outer part of the dam 10 lift by mounting loops 13.

The body 7 of the dam is preferably made from local soil.

In the particular case, before placing the GBM 10, an anti-suffusion element 8 and a reinforcing mesh 9 are laid on the main body 7 of the dam.

One of the possible ways to create a retaining dam for raising the water level in small streams after dredging is that the main body 7 of the dam is a section of untouched soil of channel 1. At the same time, dredging is carried out in sections 14 and 15 of channel 1, and the distance L between these sections choose equal to the planned width of the main body 7 of the dam, then adjust the height of the main body 7 of the dam to the desired level 16, and cover it with GBM 10. The adjusted level 16 is below the level of upstream 5 on the thickness of the outer part of the dam being built.

To raise the water level in small streams after dredging, it is preferable to erect a cascade of retaining dams, due to which the channel 1 of the small stream is evenly filled with water. After dredging is completed, in this section of the watercourse, the main body 7 of the first retaining dam is created from the soil and at least one GBM 10 is placed in the outer part of the dam 10. Then, a second retaining dam of the same design is erected 0.1–0.3 m below the mark from sea level. After the construction of the second dam along the entire length of the channel 1 of the watercourse, the following retaining dams are located similarly, located from each other at a distance of 0.1 ÷ 0.3 m below the mark from sea level.

To create such dams, GBM 10 is most suitable, containing concrete blocks 11, interconnected in order and in rows with a gap by flexible elements 12. This GBM 10 contains an anti-suffusion element 8, for example, a geotextile fabric, and / or elements 17 and 18 for complete overlapping gaps between concrete blocks 11. Both the anti-suffusion element 8 and the elements 17, 18 protect the soil of the main body 7 of the dam from leaching. The joint use of the anti-suffusion element 8 with elements 17 and 18 significantly increases the security of the main body 7 of the dam. Moreover, the width h of the gaps between at least 75% of the blocks in the GBM is from 1 mm to 25 mm for at least 80% of the overall length of the adjacent concrete blocks 11.

Elements 17 for complete overlap of the gaps between the concrete blocks 11 are shown in Fig. 7 as made in the form of four flexible strips, however, these elements can be flexible plates, one per gap. Flexible plates or strips are monolithic at one end in blocks 11, or secured in another suitable way, and the other end is left free to maintain the flexibility property of GBM 10.

When placing the GBM 10 on the main body 7 of the dam, the elements 17 for completely overlapping the gaps between the concrete blocks 11 fit snugly to the concrete blocks 11 under the influence of the weight of these blocks and completely cover the gap between them.

Elements 18 for complete overlap of the gaps between the concrete blocks 11 are made in the form of solid plates or blocks. Elements 18 must be attached to the GBM 10 with flexible connections with a gap, otherwise the flexibility of the GBM 10 will be impaired. When installing the GBM 10 with a bend, its concrete blocks 11 rest on the edges of the elements 18 and also completely cover the gap between the concrete blocks 11.

The height of concrete blocks 11 is mainly from 50 mm to 350 mm, since the effectiveness of the protective function of thinner blocks is unacceptably small, and blocks of greater thickness have excess strength for use on small streams.

Due to the relatively simple device - GBM, the simplicity of raising the water level in small streams after dredging is ensured, the dam design is simplified, since there is no need to use technically sophisticated antifiltration devices, for example, complex diaphragms-compensators. Soil dams, protected by GBM, are characterized by good manufacturability of their creation, for their construction enough ordinary excavator and truck crane. Since complex elements are not used in the present technical solution, the creation of a dam is maximally simplified, while at the same time providing a high degree of protection for the ground body of the dam. Using local soil, including that extracted during dredging works on this watercourse, a reduction in the amount of imported materials is achieved to create the main body of the dam.

Claims (22)

1. A method of raising the water level in small streams after dredging, including the erection of a retaining dam after dredging is completed in this section of the stream, characterized in that the main body of the dam is made from soil, at least one flexible concrete mat is placed in the outer part of the dam (GBM ), and the maximum dam height is 10 ÷ 80% less than the wall height of the in-depth channel. 2. The method according to claim 1, characterized in that before placing the GBM on the main body of the dam lay anti-suffusion device. 3. The method according to claim 2, characterized in that a reinforcing mesh is laid on the anti-suffusion device. 4. The method according to claim 1, characterized in that the main body of the dam is created from local soil. 5. A method of raising the water level in small streams after dredging, including the construction of a cascade of retaining dams, characterized in that after the dredging is completed, the main body of the first retaining dam from the soil is created in this section of the stream, and at least one GBM is placed in the outer part of this dam then a second retaining dam of the same design is erected 0.1–0.3 m below the mark from sea level. 6. The method according to claim 5, characterized in that after the construction of the second dam along the entire length of the channel, the next retaining dams are erected, located from each other at a distance of 0.1 ÷ 0.3 m below the mark from sea level. 7. The method according to claim 5 or 6, characterized in that immediately before placing the GBM on the dam body, an anti-suffusion geotextile and a reinforcing mesh are successively laid. 8. A method of erecting a retaining dam to raise the water level in small streams after dredging, characterized in that dredging is carried out in separate sections of the channel, and the distance between these sections is chosen equal to the width of the main body of the dam, after which the height of the main body of the dam is adjusted and covered his GBM. 9. A retaining dam for raising the water level in small streams after dredging, containing the main body, characterized in that the outer part of the dam contains at least one GBM, and the maximum height of the dam is 10 ÷ 80% less than the height of the wall of the channel after deepening . 10. The dam according to claim 9, characterized in that the main body of the dam is made in whole or in part from soil materials. 11. The dam according to claim 9, characterized in that its height is from 1.5 m to 2.5 m 12. The dam according to claim 9, characterized in that the GBM contains elements for completely overlapping gaps between all concrete blocks or between their part. 13. The dam according to claim 9, characterized in that the width of the gaps between at least 75% of the blocks in the GBM is from 1 mm to 25 mm over at least 80% of the overall length of the concrete blocks adjacent to each other. 14. The dam according to claim 9, characterized in that under the GBM an anti-suffusion element is laid on the main body of the dam. 15. The dam according to claim 14, characterized in that a reinforcing mesh is placed between the anti-suffusion element and the GBM. 16. The dam according to claim 9, characterized in that the GBM contains an anti-suffusion element. 17. The dam according to 14 or 16, characterized in that the anti-suffusion element is a geotextile web. 18. A flexible concrete mat containing concrete blocks interconnected in order and in a row with a gap by flexible elements, characterized in that it contains an anti-suffusion element and / or elements for completely overlapping gaps between all concrete blocks or between their part, and the gap width between at least 75% of the blocks in the GBM are from 1 mm to 25 mm over at least 80% of the overall length of adjacent blocks, and concrete blocks have a height of 50 mm to 350 mm. 19. Mat according to claim 18, wherein the anti-suffusion element is a geotextile web. 20. Mat according to claim 18, characterized in that the elements for completely overlapping the gaps between the concrete blocks are flexible plates or strips. 21. Mat according to claim 18, characterized in that the elements for completely overlapping the gaps between the concrete blocks are made in the form of solid plates or blocks. 22. Mat according to claim 18, characterized in that the flexible elements connecting the concrete blocks are ropes.

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