RU2776485C1 - Flood dam - Google Patents

Abstract

FIELD: hydraulic structures.

SUBSTANCE: invention relates to hydraulic structures and is intended to protect settlements from floods during seasonal river floods. To achieve the effect, the following set of essential features is used: in the flood control dam, which is also constructed as well as the prototype, across the tributary of the main river with the possibility of forming a temporary reservoir in the flood formation zone and composed of large and small stones, unlike the prototype, the stones are laid in box-shaped gabions, installed in tiers and fixedly interconnected with the formation of a trapezoidal prism in the longitudinal section with a stepped bottom and vertical top faces, at the same time, gabions filled with large stones are installed in the lower tiers, located in the tributary below the level of a regular water flow, and gabions filled with small stones are installed in the upper tiers.

EFFECT: increase the life of the dam.

5 cl, 7 dwg

Description

The invention relates to hydraulic structures and is intended to protect settlements from floods during seasonal river floods.

Known structures in the form of dams - dams that protect territories from flooding by regulating the flow of rivers. The dams are made of concrete with holes through which a safe volume of flow is carried out, and the excess water flow is retained by the dam wall in temporary reservoirs (US Pat. No. 2116401, MPK E02V 3/02, publ. E02B 3/00, published 11/10/2004).

The disadvantage of erected dams is the high cost of building concrete structures and the impossibility of their construction in mountainous conditions due to the lack of transport routes.

Known flood control dam according to US Pat. No. 2552361, IPC E02B 3/00, publ. 06/10/2015, constructed on a tributary of the main river with the possibility of forming a temporary reservoir in the zone of flood formation. The dam blocks the inflow channel in the form of a trapezoidal prism made of permeable bags with loose filler. The bags are laid along the tributary channel in layers, with alternating layers with a longitudinal and transverse arrangement of the bags relative to the channel and with an interval relative to each other.

The disadvantage of the structure is the change in the shape of the structure over time, tk. the bags that form the dam change their position due to the fact that they do not fit snugly against each other.

One of the closest analogues of the proposed device in terms of technical essence and purpose is a flood control dam as part of a territory flood protection system (US Pat. RU No. 2389845, IPC E02B 3/02, publ. 20.05.2010). The dam is being built on a tributary of the main river with the possibility of forming a temporary reservoir in the zone of flood formation. The structure is a stone embankment laid across the riverbed. Large stones are laid in the lower zone, small ones in the upper zone. The location of the dam is chosen in narrow rocky canyons and constructed in an explosive way.

The disadvantage of the structure is its fairly quick failure due to the fact that the upper layers of the dam, designed to delay the flood and formed by small stones, are washed out or fall into the gaps between large stones during heavy or prolonged floods, creating a barrier to regular flow. In addition, the construction of rockfill dams with the collapse of rocky slopes by explosion is an insufficiently perfect process due to the limited possibilities for controlling the explosion and insufficient accuracy in predicting its results.

Compared with the prototype, the claimed invention allows solving the problem of the service life of the dam, while using more modern technologies in its construction.

To solve the problem, the following set of essential features is proposed: in the flood control dam (constructed, like the prototype, across the tributary of the main river with the possibility of forming a temporary reservoir in the flood formation zone and composed of large and small stones), unlike the prototype, the stones are laid into box-shaped gabions installed in tiers and fixedly interconnected with the formation in the longitudinal section of a trapezoidal prism with stepped lower and vertical upper faces, while in the lower tiers located in the tributary below the level of a regular water flow, gabions filled with large stones are installed, and in upper tiers - gabions filled with small stones.

For more effective protection against floods, the flood control dam close to the upper tiers of the channel part can be supplemented on both sides with coastal structures in the form of dams, the downstream slopes of which are formed in the form of a wall of box-shaped gabions with stepped external laying, and the upstream slopes are filled with soil. The lower slopes of coastal dams can also be formed by directly laying mattress-mattress gabions in the ground.

To reduce soil suffusion, geotextiles can be laid between the gabions and the soil slope.

In addition, to further reduce the suffusion of the soil of the dam, the upper (ground) slope can be planted with shrubs with a deep root system.

This set allows you to get a new technical result compared to the prototype and while maintaining the advantages of the latter. Like the prototype, the dam provides a fairly effective protection of territories during a flood, in which a safe amount of runoff is passed through the gaps between large stones of the lower tiers, and overestimated (flood) water flows are retained by the upper tiers of the dam in temporary reservoirs. At the same time, coastal dams, due to the retention of flood waters in the floodplain of the tributary, provide an additional protection measure aimed at reducing the height of the flood peak and increasing the time for water to enter the main river. But unlike the prototype, the channel part of the dam, made of fixedly interconnected box-shaped gabions, forming a trapezoidal prism in the longitudinal section, due to the optimal ratio of stresses in the base and the height of the prism, has a higher static stability of the structure, which accordingly allows to increase its service life. . In addition, a prism with a vertical pressure (upper) and inclined drain (lower) surfaces helps to reduce the energy and speed of the flood flow during its retention and overflow over the crest of the dam, which creates optimal conditions for all modes of operation of the structure: passage, retention and overflow of flows.

Comparison of the proposed device and the prototype showed that the task - to increase the service life of the dam - is solved as a result of a new set of features, which proves the compliance of the proposed invention with the criterion of patentability "novelty".

In turn, the conducted information search in the field of hydraulic engineering did not reveal individual distinguishing features of the claimed invention, which allows us to conclude that it meets the criterion of "inventive step".

The essence of the invention is illustrated by drawings, where

figure 1 shows the layout of flood control dams and temporary reservoirs in the river basin,

figure 2 - plan of the dam with channel and floodplain (coastal) parts;

figure 3 - view from the downstream of the channel part of the dam;

figure 4 - longitudinal profile of the dam with coastal structures (dams);

figure 5 is a cross section of the channel part of the dam with coastal structures (dams),

figure 5, 6 - options (cross-sections) of the lower slopes of coastal structures (dams),

figure 7 shows a graph of the skipping flood flow.

Flood dams 1 are installed in the zone of flood formation on the tributaries of the main river 2, which flows past settlements 3 and flows into reservoir 4 (figure 1). The channel part of the dam 1 (figure 2), blocking the inflow, is formed from fixedly interconnected gabions 5 with the formation in the longitudinal section (figure 3, 4) of a trapezoidal prism with a stepped bottom and vertical top faces (fig. 5). Depending on the height and width of the water area, gabions 5 in the dam are installed in several tiers and rows and connected to each other in height, width and length with double U-shaped brackets or UP-Twin brackets.

Gabions of the lower tiers are filled with heavy and large natural stones, both polished and cornerstone, with a fraction of at least 15-30 cm, a weight of at least 23 kN / m ³ and a porosity of 0.3-0.5 (basalt, granite, dense limestone ). The stones are laid in such a way that sufficiently large voids form between them, allowing regular (safe) flow to pass through. The lower gabions are a rectangular frame made of steel bars, interconnected by welding or using crimp fittings (see US Pat. RF No. 200665). The dimensions of the frame, depending on the depth and width of the inflow, can have a height of 0.5-1 meter, a width of 1-2 m, a length of 2-6 m. Jumpers are installed inside the gabion, which prevent the walls from moving apart under the weight of bursting stones.

Gabions with small stones (pebbles, granite chips) are installed in the upper tiers, laid in such a way as to ensure uniform settlement around the entire perimeter and area and create a barrier to the excess flow of flood waters. Like the lower gabions, the upper gabions can be made in the form of a rectangular frame with a height of 0.5-1 meter, a width of 1-2 m, a length of 2-6 m, on which a woven wire mesh is fixed.

On both sides of the channel part of the anti-flood dam 1 in the coastal zone of the inflow close to the dam 1, coastal structures are formed in the form of dams 6, over which the water flow, when entering the floodplain, is passed with overflow over the ridge (Fig. 4-6). Structures (dams) 6 have two slopes: upstream (near the upstream) and downstream (drainage) - in the direction of the flow to the main river. To strengthen the dam, its downstream slope is formed from box-shaped gabions 5 (Fig. 5) or from gabions of a mattress-mattress form 7 (Fig. 6). Laying gabions in the downstream slope of the dams prevents erosion (suffusion) of the soil of structures from the upstream side, and the stepped shape of the downstream slope drain surface reduces the flow rate.

On the upper slope of the dam 6, a shrub 7 is planted, which has a branched root system 8.

The proposed flood control dam operates as follows.

In normal non-natural seasons, the structure does not prevent the passage of water from mountain tributaries to the main river, passing household runoff through the lower tiers of dam 1. When it rains or during heavy snowmelt, a safe volume of runoff is passed through the gaps between large stones of the lower tiers of dam 1, and overestimated (flood) water discharges are delayed by the upper tiers of the dam 1 in temporary reservoirs and by coastal dams 6 in the floodplain of the tributary, followed by overflow of water over the crest of the structures. As a result, the time of arrival of the flood flow into the main river increases to the value t ₂ , while the height of the flood peak decreases (Fig. 7).

The use of the invention due to the stability of the structure to powerful flood water flows (such as the catastrophic flood in Krymsk, 2012) and long-term floods (such as the flood in Tulun, 2019, the discharge period of which was 4 days) , allows you to increase the service life of the flood control structure. At the same time, the construction of a structure, which, as a rule, is carried out on mountain slopes, can be carried out using local crushed rock material and using manual labor or small-scale mechanization, which greatly simplifies and reduces the cost of the work performed.

The proposed design was developed by specialists of TR Engineering LLC. Calculations were made that showed the possibility of using the dam as part of a scheme to protect the city of Krymsk and other settlements in the Caucasus, Primorsky Krai, etc. from floods.

The foregoing allows us to conclude that the invention meets the criterion of "industrial applicability".

Claims (5)

1. Flood control dam, constructed across the channel of the tributary of the main river with the possibility of forming a temporary reservoir in the zone of flood formation and built of large and small stones, characterized in that the stones in it are laid in box-shaped gabions installed in tiers and motionlessly connected to each other with the formation of longitudinal section of a trapezoidal prism with a stepped bottom and vertical top faces, while in the lower tiers located in the tributary below the level of a regular water flow, gabions filled with large stones are installed, and in the upper tiers installed on the lower tiers, gabions filled with small stones . 2. The flood control dam according to claim 1, characterized in that it is supplemented on both sides close to the upper tiers of its channel part with coastal structures in the form of dams, the downstream slopes of which are formed from gabions with stepped external laying, and the upstream ones are filled with soil. 3. Flood control dam according to claim 2, characterized in that box gabions are used as gabions in the downstream slope. 4. Flood control dam according to claim 2, characterized in that mattress-mattress gabions are laid as gabions in the downstream slope. 5. Flood control dam according to claim 2 or 3, characterized in that the upper slopes of coastal structures are planted with shrubs with a deep root system.

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