Coastal protection structures. Bank protection works Special equipment for bank protection works of the reservoir

Coastal protection belongs to the category of measures aimed at protection against floods and erosion. Bank protection works make it possible to make the soil resistant to water erosion and may well be done by hand.

Why and in what cases is shore protection carried out

As a rule, bank protection of a river or pond combines a set of works that contribute to strengthening coastline and help protect the coastal line of a natural or artificial reservoir from undercutting, landslides and erosion.

The destruction of the coastal slope can be caused by currents and waves, as well as erosion as a result of the negative impact of storm flows.

Erosion and subsidence of the banks often provokes shallowing and overgrowing, not only the reservoir itself, but also the surrounding areas. This exposes all structures and structures that are built on the territory of the coastal zone to the threat of collapse. To prevent such undesirable processes, bank protection is carried out.

Options for strengthening the shoreline of the pond and river

You can strengthen the coast in several ways and using different materials, which different quality characteristics, durability and cost:

• strengthening system with flexible design, represented by gratings in the form of bases for retaining walls, which makes it possible to provide reliable protection for communications laid along the coast;
• reinforcing system using plant components, including larch wood, which has increased resistance to soaking and decay processes;
• reinforcing system with a rigid structure in the form of steel or PVC sheets, retaining walls, cemented soil or concreted stones.

Before carrying out the event, it is necessary to evaluate the scope of work and select best option.

How to strengthen the river bank with a larch log (video)

Bank protection with gabions

Work with gabions is easy to perform and economical. The advantages of using such material are as follows:

• the material is able to effectively withstand the onslaught of waves and active water flows;
• has a long operational life over a hundred years;
• low costs for arrangement and the ability to dismantle if necessary;
• finished construction differs in ecological cleanliness and decorative attractiveness.

It is very easy to make such a design on your own, but it is advisable to adhere to the following simple rules mounting:

• you need to mount on the problem area and fill natural stone;
• the total number of gabions, as well as the method of their installation, must be calculated individually and depends on the height of the slope;
• at the final stage, a protective decorative trim by filling with soil and plant seeds, which allow you to strengthen the structure.

The maximum strength of the gabion system is achieved after five years of operation. During this time, the coastline is able to become one with the surrounding landscape.

Strengthening the river shoreline with wooden piles

This method belongs to the category of fairly common methods. Installation cost wooden piles will directly depend on the quality and value of the wood used in the work.

The advantages of the method include the ability to perform work without the presence of special skills, environmental friendliness of the material and quite attractive appearance designs. However, the tree has relatively short term exploitation, and such strengthening involves large labor costs.

We strengthen the coast with PVC sheet pile

Fasten with a tongue PVC based maybe even a steep shore. This method is considered to be the fastest and most cost-effective. Most often used on too steep or steep banks.

The execution technology consists in connecting sheet piles into a single protective wall. The installation is carried out using special hydraulic equipment, and for reliability and durability, the piles are fixed as firmly as possible by means of longitudinal ribs.

The use of natural stone

If the coastline of the reservoir has a slope of no more than 20º, then for the purpose of strengthening it can be used natural stone in the form of pebbles, buta or boulders various shapes and size. Such material allows you to give the landscape of the territory an attractive and unique appearance. Booths of various sizes and coloring look especially expressive.

The most commonly used are pink, red, gray and dark rubble stone. Before laying, it is necessary to carry out a number of preparatory measures aimed at creating a base from geotextile, geogrid or geogrid.

The most difficult is the arrangement of the so-called "stone castle", which is a dense stacking of large boulders in a strictly designated place in accordance with the shape of the stone and its color. Such an event is carried out manually, which allows you to adjust the aesthetics of the appearance. Despite the fact that this process is very long and laborious, the result is a durable and most attractive reinforcement.

How to strengthen the coast with gabions (video)

Geogrid and reinforcing mesh

The use of a geogrid is an inexpensive and reliable option, especially if the shoreline sags. Distinctive feature method is represented by the opportunity to get a very beautiful and individual appearance of the structure, as well as a convenient, completely non-slip descent to the water and landfall.

A good visual effect is provided by filling cells with river or sea pebbles., as well as marble chips in the form of a mosaic. Strengthening the shore using a reinforcing mesh of special chain mail weaving and tumbled or rubble stone looks no less impressive, and is also distinguished by extraordinary reliability and durability.

How to strengthen the shore with your own hands using plants

Application of various biological objects and elements plant origin along the water's edge is one of the most troublesome and capricious ways of bank protection as natural pond, and artificial reservoir. Plants used:

• fast-growing willow easily withstands prolonged flooding;
• powerful root system ash is resistant to strong gusts of wind and low temperatures, so the plant grows well on open areas;
• reeds and sedge not only help to strengthen the coastline, but also prevent clogging and shallowing of the reservoir;
• alder, which has shore-protecting and water-regulating properties, is of great soil protection value;
• hazel is widely used for fixing slopes and beams, and fallen leaves are perfectly mineralized and enrich the soil layers;
• in order to improve the structural parameters of the soil and prevent sagging, bird cherry is widely used;
• ailanthus, which gives abundant root offspring, is used to protect slopes, embankments and ravines from shedding and sagging.

A good and fairly fast strengthening effect can be achieved with the cultivation of such popular coastal plants as iris, loosestrife, water mint and comb or tamarisk.

How to strengthen a steep bank

It is the sheer coastline that quite often needs timely and well-executed fortification to prevent the flooding of the adjacent territory and the sinking of soils into the water of the reservoir. Accurately and reliably arrange such a coastal fortification can be not only capital options, but also decorative ways:

• with the use of gabion-box structural systems, made on the basis of the most durable and very durable galvanized double wire twisted mesh;
• when combining gabion systems with strengthening the coastal zone with larch or geogrid, the service life is more than eight decades;
• the use of Renov mattresses in the form of planar gabion structures made of metal mesh with double twist and galvanized or polymer coated;
• through Siberian larch, which is distinguished by excellent durability and natural properties, which does not allow disturbing the ecological system of the reservoir;
• sheet pile partitions in the form steel sheets, as well as reinforced concrete structures, PVC and wood with high bearing capacity.

It is quite popular and in demand on the territory of our country to strengthen the coastline with cemented soils, consisting of cement M-300 or M-400, loam or loess-like sandy loam and water, thoroughly mixed and laid in wooden, metal or plastic formwork.

Strengthening the coast with a sheet pile (video)

Bank protection can be done different ways, which directly depend on the choice of material used and the laying option along the artificial or line. Regardless of the type of material used in the course of work, strengthening the shore is capable of practical and aesthetic functions, which helps prevent soil erosion and helps to ennoble the surrounding area.

Purpose and types of coastal fortifications. Coastal fortifications are erected with a radical improvement of difficult areas in rivers with various types channel process. They protect the banks of rivers from erosion by currents, ship waves, groundwater, as well as from destruction by ice drift. Coastal fortifications make it possible to secure a ship's passage at the leading bank, eliminate sources of sediment inflow into the river, prevent damage to hydraulic structures near the coast, and preserve buildings, lands and forests in the coastal strip of the river.

The main task bank protection works is to prevent erosion of concave banks. To do this, an analysis of the channel reformations of the site is carried out in order to establish the extent of the bank slope subject to erosion, as well as an analysis of hydrological data (level height, flow velocity, amount of sediment, etc.), which allow choosing the type of coastal fortifications and their design.

Distinguish coastal fortifications active and passive action. The former significantly affect the structure of the flow in the coastal area, while the latter only protect the coastal slope from erosion.

The main fortifications that affect the structure of the flow near the coast are coast protection spurs(short high semi-ponds). A system of such spurs is usually located near a concave coast, contributing to a decrease in the flow velocities along the protected coastal slope, which leads to a decrease and even to the cessation of coastal erosion, and in some cases to the formation of a new coastal slope after filling the gaps between the spurs with sediments. Sometimes spurs are erected during the construction of semi-dams to ensure the stability of the opposite, easily eroded straight or slightly curved shore, in order to provide the necessary erosion of the bottom within the ship's passage.

Bank-protecting high spurs are especially effective on small and medium-sized rivers, where, after a short high flood with high speeds current, a long low water period with low flow rates is observed. On such rivers, erosion of the banks is observed only during floods, which can be prevented by such spurs.

Another type of bank protection structures that affect the structure of the flow are bank reinforcements that create additional roughness of the channel near the eroded coast or directly on its slope. Such fortifications include: through pile rows; pile gantry bushes; flexible metal mattresses made of wire; artificial algae, etc. The main purpose of these fortifications is to reduce the flow velocity in the area of ​​the coastal slope by creating additional resistance to the flow.

Particularly good results are obtained when such fortifications are used on rivers, where the flow carries a large number of sediment. In this case, the protection of the coast from erosion contributes to the deposition of larger sediments in the area where such fortifications are located. As a result, a stable coastal slope is formed, providing favorable conditions for navigation.

Passive fortifications that protect the coast from erosion are coastal coverage. They fix the position of the eroded shore, favorable for navigation, or protect the righting and other structures from being bypassed by the stream at their junction with the shore.

Coastal coverage can be solid, fixing the coastal slope along the entire length of its erosion, or tape, which cover only parts of the coastal slope that are separate along the length (ribbons) located at certain distances.

Continuous coastal coverings are most effective in improving navigation conditions on rivers with relatively low but prolonged floods and significant flow rates. On such rivers, the erosion of the banks occurs during long period time, therefore, it is possible to prevent its destruction only by a continuous covering of the coast.

Continuous strengthening of the coastal slope during high and short floods requires large expenditures and can be justified mainly in those cases when it is necessary for several branches of the national economy.

Calculation of coastal protection spurs. When calculating coastal protection spurs, they are first determined length, height and distance between them and then check stability of ground spur heads attachment when flowing around them and when exposed to ice loads.

The length of each spur is determined by the outline of the created bank slope, i.e. distance between existing line (cut) coast and the boundary of the straightening line, and is usually 20-50 m(Fig. 10.39). The decoding of the letter designations is given above, in relation to the formulas (10.44-10.50).

Rice. 10.39. Shore protection spurs:

a - a plan for the location of structures; b - longitudinal section along the axis of the structure

Coastal protection spurs are significantly higher than low water semi-dams. The marks of the crests of their heads are usually taken without much consideration for 2.5-3.5 m above design level. In this case, the crest of the spur is structurally given a longitudinal slope from 1:10 before 1:25 with an ascent to the shore to which they adjoin. Often the mark of the crest of their root coincides with the low-water edge of the coast.

The river slope of the head of the spur usually starts from 2.5 before 3.0 , and laying the upper (pressure) slope and lower (drain) slopes depend on the technology of construction and the size of the soil from which the body of the structure is poured. When spurs are washed by a dredger from sand into a stream with a flow velocity of 0.5 before 1.5 m/s the laying of the upper slope is approximately 3-5 , and the bottom 5-15 .

When backfilling the body of the structure using single-bucket or multi-bucket shells or in a pioneering way with the help of bulldozers, the laying of slopes is significantly less. Approximately, it is possible to take the laying of the upper slope equal to t in =t 0 + 0.5 , and the bottom m n = m 0 +1.0 , where t 0 – laying a slope of the same material in a calm (no flow) water.

The distance between spurs located on a straight or slightly curved section of the channel (see Fig. 10.39, a) is assigned equal to the critical distance calculated by the expression

, (10.44)

where:  - coefficient showing how many times the distanceS kr from the head of the structure to the point of intersection of the flow spreading curve with the boundary of the straightening route is greater than the length of the spurl w .

Coefficient  depends on the resistance of the channel to the movement of the flow, determined by the hydraulic coefficient of resistance

, (10.45)

where: With – Chezy coefficient;

B - everyday width of the channel;

h with is the average depth in the cross section.

The numerical value of the coefficient  determined by the nomogram (Fig. 10.40), on which h w is the average height of the spur. The dashed line shows the sequence when using the nomogram.

Rice. 10.40. Coefficient dependency graph

= f(B, ,h w /h)

When designing spurs on a curved section of a concave bank, the critical distance is found by the following expression

. (10.46)

Options  and  are determined by the following formulas:

, (10.47)

, (10.48)

where: r 0 – average radius of curvature of the concave bank (straightening track).

Checking the stability of fastening a spur from rockfill is reduced to determining the diameter of the stones that will be in equilibrium under the action of the current in the region of the head of the spur. Such a calculation can be done according to the formula of V.V. Balanina

, (10.49)

where:  G is the flow velocity near the head of the spur;

 – spur head slope angle;

 to and – density, respectively, of stone and water.

In this case, the speed at the head of the spur is determined by the formula of V.V. Degtyarev

, (10.50)

where:  b - the speed of the current in the area of ​​the spur head in the domestic state at a level coinciding with the mark of the crest of the spur head;

 w – cross-sectional area occupied by the body of the spur;

 – total cross-sectional area in the alignment of the structure at the water level mark flush with the crest of the head of the spur.

When erecting spurs from soil and other small-clastic materials, the structures are quite massive. Therefore, during a short-term ice drift, only local damage to the upper slope is possible in the form of individual uplifts of the soil above the place of impact of a floating ice floe. To provide long work, head (upstream) the spur, which takes the main load from the ice impact, is made of a more massive profile with the strengthening of the upstream and downstream slopes, as well as the crest and head of the structure.

Calculation of coastal coverings. When calculating the coastal cover, first of all, its length and width are found and the size of the stone or the thickness of reinforced concrete slabs or asphalt mattress is determined. In addition, the stability of the fortifications against the effects of waves and ice loads is checked.

To select the strengthening of the eroded coastal slope, first of all, it is checked for stability against the influence of current velocities. To determine the flow velocities in the stream near the shore, full-scale or theoretical flow plans are built on the improved section of the river at the calculated water levels: medium-high flood level and medium-low water level. If the average high level of the flood is higher than the floodplain marks, then the water level is taken as the calculated one on a level with the marks of the floodplain or low water edges of the coast, since at this time the highest flow rates in the low water channel are observed.

The values ​​of the current velocities in the jet adjacent to the coastal slope obtained as a result of constructing the flow plans make it possible to reasonably choose the type of shore strengthening that will ensure reliable protection coastal slope from erosion by the flow. In this case, the allowable flow velocity for the selected fortification should be greater than the maximum design flow velocity with some margin.

Tables of permissible speeds for various types of bank protection are given in the relevant technical specifications, departmental norms and design rules for bank protection, for example, in the Guide to improving navigation conditions on free rivers.

The length of the bank slope reinforcement is established on the basis of an analysis of the combined plans of the river section and flow plans at characteristic water levels over several years. In this case, the beginning and end of the fortification are chosen with a margin of 15-20 m compared to the beginning and end of the coast erosion zone.

To determine the width of the coastal fortification, the slope is divided into four zones: I– underwater slope zone (below low low water levels); II– zone of variable levels (during spring and summer-autumn floods); III– zone of wave run-up and surge phenomena; IV – surface slope zone (see Fig. 10.41).

The fastening width in each zone is equal to

, (10.51)

where: H i – zone height;

m i – laying (slope of the slope of the coast in the zone).

The height of the first zone H 1 which is the margin in the fastening of the surface slope above the height of the waves on the shore, taking into account the height of the wind surge of water near the shore, is taken in accordance with building codes and rules, as for structures III- IVclass, respectively, not less than 0.5-0.3 m with the probability of exceeding the highest water level, respectively 3-10%.

Height of the second zone H 2 is equal to the sum of the rollover heights h n waves on the slope and wind surge  h

. (10.52)

Rice. 10.41. Scheme for the calculation of coastal fortification (covering):

1 - initial position of the underwater part of the coating; 2 - coastal coverage;

3 - strengthening the horizontal section of the low (flooded) coast

In this case, the wave run-up height is calculated by the formula

, (10.53)

where: To w - coefficient of roughness and permeability of the slope or fastening;

h w and in – respectively, the height of the wind or ship wave and the wavelength;

t– embankment.

The height of the wind surge near the shore

, (10.54)

where: K – proportionality factor;

 in – estimated wind speed at a height of 10 m from the water surface;

D – wave length;

h c – average depth of the reservoir along the acceleration line;

 – the angle between the normal to the shoreline and the direction of the wind.

The calculation for the height of the wind wave run-up and the surge of water is performed only when strengthening the banks at the mouth sections of large rivers, and for the ship wave - only on small rivers and in narrow navigable branches of the channel, as well as in areas where the ship's passage is laid near the coast.

The height of the third zone H 3 are determined according to the data of long-term observations of water levels at a reference hydrological post as the difference between the average of the highest levels of spring flood and the low low water level. If the average of the highest flood levels is above the floodplain shore, then the height of the third zone is found as the difference between the floodplain marks and the low low water level.

In addition, with such a low floodplain, the magnitude H 2 and b 2 are equal to zero, and the width of the fastening b 1 goes beyond the edge of the floodplain shore and is taken equal to approximately 3-5 m.

Height of the fourth zoneH 4 equal to the sum of household depth h b at the foot of the slope at a low low water level and the depth of possible local erosion h p unreinforced bottom in the same place after performing bank protection works:

. (10.55)

The depth of local erosion of the unreinforced bottom directly near the end of the underwater anchorage can be approximately determined by the formula of I.A. Yaroslavtsev

, (10.56)

where:  c is the average current velocity in the jet near the shore;

m = ctg - laying of the underwater part of the slope of the coast;

 – the angle between the direction of flow during the design flood and the direction of the bank slope (taken at least 30 °);

d – the diameter of the soil particles at the bottom, which, according to the particle size distribution curve, is taken to correspond to 85% probability (withd< 1 mm the last term in this formula can be ignored).

Thus, the full width of the bank slope anchorage

. (10.57)

In the absence of the necessary data to perform calculations of the depth of local bottom erosion at the bottom of the anchorage, the width of the anchorage at intensely eroded steep banks is brought to the line of greatest depths. If the underwater slope in the lower part noticeably flattens out, then the bottom is fixed to the bottom of the slope with a margin 10-15 m.

Establishment of slopes for a surface slope with all fortification structures, except for biological and rockfill, should not be steeper than 1:2 to avoid slipping of the slope reinforcement.

In the presence of a wave action on the shore fortification, the mass of the stone, which will be on the slope in a state of ultimate equilibrium, is determined by the formula

, (10.58)

where:  to and  – respectively, the density of stone and water;

h in and in – respectively height and wavelength;

t – riprap slope.

Knowing the mass of a stone that will be stable on a slope when exposed to a wave, the calculated size (diameter)

. (10.59)

The thickness of the fastener from the graded stone outline must be at least t to  2.5 d to , and when using unsorted stone t to  3 d to .

The calculation of the shore fastening from reinforced concrete slabs is reduced to finding their thickness according to the formula

, (10.60)

where:  in – wave backpressure value;

 pl and – respectively, the density of the plate and water;

 – angle of inclination of the protected bank slope to the horizon.

When using flexible reinforced concrete coatings as coastal reinforcement, their thickness is determined by the formula of I.Ya. Yaroslavtsev

(10.61)

where:  andK – coefficients taking into account, respectively, the continuity of the coating and the effort from the pulsating load under wave action;

 c – average current speed in the coastal area.

Coefficient values  and K are given in table. 10.1.

Bank protection works are activities carried out in order to protect the banks of rivers, canals and reservoirs from destruction. The concept of bank protection works usually includes a set of works to protect the banks mainly from the dynamic influence of water (wave impact, increased current velocity, etc.). The importance of strengthening the banks of canals and rivers especially increases with the existence of steamship traffic, since the waves produced by steamships are the main destroyers of banks. It should be borne in mind that bank protection works cannot be separated from works to straighten the riverbed. Bank protection works carried out in conditions of easily liquefied and water-eroded soils are included in the complex of straightening works. Sufficiently large fluctuations in the water level, the presence of wide floodplains, as well as the formation of icing and bottom ice on many rivers significantly increase the cost and complicate the bank protection works. Newly built, under construction and planned for construction canals put bank protection works in a number of very complex and responsible works in construction.

When carrying out bank protection works, a variety of building materials can be used: stone, brick, brushwood, earth, piles, etc. The brushwood used for fashine work can be heterogeneous or only willow. Heterogeneous brushwood is usually used only for those parts of the fortifications of the banks that are constantly under water. AT Central Asia and in the Caucasus, fascines were often made of comb, which resists decay quite well. The reed fascines used, due to their fragility, are considered exclusively as temporary, unsuitable for any serious structures. Stones used in bank protection works must be resistant to erosion. The most suitable for these purposes are granites, quartzites and dense limestones. The earth is used in the construction of brushwood structures as ballast for loading brushwood masonry into the water. Stakes used in brushwood work are made from thick branches and thin tree trunks, and piles are made from roundwood. Ropes (the so-called "tackle") are used in this case, hemp, resinous. For knitting heavy fascines, annealed wire is used. To the main bank protection works on the rivers, made from the above materials ov, include brushwood lining, immersion of heavy fascines, rock fill, dry stone masonry and slope turfing.

The choice of a method for strengthening the banks depends on the nature of its destruction, the outline of the coast in terms of the regime and nature of the river flow, as well as the available local or easily delivered cheap building materials. The height to which the coast is strengthened directly depends on the levels of water and ice. The upper parts of the coast, which are above the horizon of the most high waters they are usually strengthened only when they are not protected by vegetation or are destroyed regardless of its influence. Destructive impact external influences manifests itself mainly in the lower part of the coast - below the horizon of "middle" waters. Therefore, the banks are strengthened mainly in their lower part. To strengthen the underwater part of the coast, fashine mattresses were often used with their loading with stones, as well as simply stone fill.

When strengthening the banks of the canals, as an option, piles can be driven along the edge of the lowest water horizon in the canal. Boards can be laid directly behind them, and prisms from dry masonry can be arranged behind them.

Separately, it should be written about the strengthening of the coastal slopes of rivers and canals with gabions. Strengthening slopes with gabions is as follows. Forms-boxes are woven from galvanized steel wire, which are subsequently filled with stones. Gabions (usually prismatic or cylindrical shape) are interconnected, resulting in an array that resists shear and erosion quite well. Usually, gabions first make the foundation, and then the working part of the bank protection structure itself. The base is often made of relatively thin gabions with a thickness of about half a meter. The working part may consist of gabions of various sizes, arranged in one or more rows, according to the height that they want to give it.

In cases where the current velocities are low, to protect against erosion of the gently sloping and fairly wide underwater slopes of the coast, consisting of fine sand and silt deposits, mats of thin willow branches were often used. Such mats were knitted at the place of their laying on ships. They were made up to fifty meters wide. The ships moved along the coast, and the mats gradually descended onto the underwater coastal slopes. Immersion of such mats was carried out by throwing stones on them. Here we should also mention the practice of carrying out bank protection works using

Seas, lakes, reservoirs, canals, etc.) from the destructive effects of waves, currents, pressure of water and ice, and others natural factors. Bank protection structures are being erected to prevent coastal destruction and flooding of settlements, industrial facilities, roads, bridges, communication lines, valuable forest and agricultural land, cultural and historical monuments etc.

Requirements for bank protection structures: efficiency and reliability (durability) of structures, ease of installation, the possibility of maximizing the use of local building materials and carrying out repair and restoration work, cost-effectiveness.

Bank protection is carried out within the water areas of ports and on open coasts. In the first case, it is designed to protect undeveloped sections of the coastline from erosion and ensure the improvement of the port area. In the second case, bank protection structures are built to protect against erosion the area where the coastal strip meets resort complexes, settlements, industrial facilities, railways and roads.

Strengthening the coast is especially important in the construction of drainage channels, spillways of dams, in the construction of supports, bridge cones, embankments for railways, highways.

According to the main material, bank protection structures are divided into wooden, stone, steel, concrete and reinforced concrete.

According to the nature of interaction with the water flow, bank protection structures are divided into active ones, which use the energy of the stream to work on alluvium and the preservation of coastal sediments, and passive ones, which oppose the water flow only by the strength and stability of their structure.

Active bank protection structures on the seas and lakes include sediment-retaining semi-dams (bunions), breakwaters and breakwaters, on rivers - transverse semi-dams regulating dams, jet-directing shields.

Passive shore protection structures on the seas - wave walls, a draft of large blocks and figured massifs, on rivers - a stone throw, mattresses, gabions, concrete and reinforced concrete slabs and etc.

The choice of a complex of bank protection structures and their types depends on the relief of the coast, its hydrogeological regime and geological structure.

Mol- a hydraulic fencing structure to protect the port water area from waves, adjoining the shore at one end. At the same time, the pier can serve to accommodate berths and transshipment devices.

In ports located on the open coast, two converging or parallel piers are built with a gate between them (paired piers). If the port is located in a bay, the shores of which partially protect the water area from wind and waves, they are usually limited to one pier. The design and type of the pier are mainly determined by the hydrological regime and geological conditions of the port area.

There are moles:

• sloping type - constructed by a sketch of stone or concrete masses;
• vertical type - in the form of walls erected from masonry, concrete or reinforced concrete arrays;
• combined type (a combination of the first two types).

The head (protruding into the sea) part of the pier is made 1–1.5 m higher than the rest, and a signal light or beacon is installed on it.

Breakwater, or breakwater- a hydraulic structure on the water (in the sea, on a lake, reservoir or river), designed to protect the coastline or port water area from waves, currents, ice and sediment. It differs from the pier in that it does not adjoin the shore.

There are breakwaters of gravity type, pile, floating, hydraulic, pneumatic, protective (surrounded by water) and coast-protective (located directly at the coast).

The jet guide shield is designed to guide flows and increase the path of movement Wastewater in cleaning facilities.

Semi-damming(buna, transverse dam) - a hydraulic structure designed to regulate the regime of the water flow and protect the sea or river bank from erosion. For the construction of a semi-dam, soil, stone, concrete, fascines, gabions are used. Semi-dams are installed vertically or at some angle to the shore. Bottom semi-dams serve to protect the foundations of coastal structures (dams, retaining walls, etc.) from erosion.

Depending on the goals and local hydrotechnical conditions, bank protection uses various designs and materials. Bank protection structures can be made in the form of embankment walls or in the form of protective clothing laid on a properly planned bank slope.

Slope bank protection can be completed faster and at a much lower cost than the construction of embankment walls. However, bank protection structures of this type cannot always be applied. It must be borne in mind that if the river bank to be strengthened is high enough and complicated by weak rocks, then to ensure the stability of the slope, it will be necessary to allocate a strip of territory of considerable width (with a bank height of 15 m above the water level and an average slope of 1: 3, the lost strip of territory will be 45 m). It is not always possible to refuse to use such a significant strip of coastal territory with the limited size of the construction site.

Slope strengthening of the coast also cannot be applied if it is necessary to use the coastline for mooring ships and organizing loading and unloading operations.

When improving the coastal strip within locality both sloping bank protection structures and embankment walls can be used, depending on the architectural and planning solution of the coastal strip.

When carrying out bank protection works in the area green spaces Combined two-tier bank protection structures are used, consisting of a low retaining wall flooded by flood waters and a slope fixed with sod cover and shrub vegetation. Embankments of this type, in addition to their main use as bank protection structures, can also serve to organize recreation for the population.

The complex of city embankments, in addition to bank protection structures, includes special devices in the form of descents - moorings, stairs, etc. The walls of city embankments are covered at the sidewalk level with cornice stone and fenced with gratings or parapets.

Yu.V. Bogatyreva, A.A. Belyakov

Bank protection structures are structures for protecting the shores of reservoirs (rivers, seas, reservoirs, canals, etc.) from the destructive effects of waves, currents, pressure of water and ice, and other natural factors. They are erected to prevent destruction (washout) of the coast and flooding of settlements, industrial facilities, roads, bridges, communication lines, valuable forestry and agricultural. lands, cultural and historical monuments, etc. In the resort areas of B. with. are used to preserve, create and expand beaches. Requirements: efficiency and reliability (durability) of structures, ease of installation, the possibility of maximizing the use of local building materials and carrying out repair and restoration work, cost-effectiveness. According to the nature of interaction with the water flow, they are divided into active ones, which use the energy of the flow to work on alluvium and the preservation of coastal sediments, and passive ones, which oppose the water flow only to the strength and stability of their structure. To active on the rivers - transverse semi-dams, regulating dams, jet shields. Passive on the rivers - riprap, mattresses, gabions, concrete and reinforced concrete slabs, etc.

7.3. Embankments

Embankment - a structure that borders the coastline of the sea, river. The embankment serves to give the coast the correct shape, strengthen it, protect it from erosion, for convenient passage and travel along the coast (city embankments), for mooring ships directly to the territory, facilitating the transfer of goods, as well as the transfer of passengers from the coast to the ship and back ( port embankments). Embankments in cities are driveways (streets) located along the coast and limited on one side by urban development or a park. Embankments as structures are usually made in the form of retaining walls, less often in the form of a through structure of a trestle type.

Rice. … Types of bank protection structures:

a-g - slope type; d, e - semi-sloping type; 1 - riprap from sorted stone; 2- return filter; 3 - emphasis (stone banquet); 4 - backfill (sand, sandy gravel soil, etc.); 5 - riprap from unsorted stone; 6 - reshaping profile; 7 - concrete or reinforced concrete slab; 8 - emphasis (array); 9 - laying out with a stone weighing at least 100 kg; 10 - emphasis (ordinary or hollow array); 11 - stone bed; 12 - unloading stone prism; 13 - sheet pile or a continuous row of piles; 14 - head, 15 - anchor rod; 16 - anchor plate

The architectural classification of embankments can be based on the following features: functional purpose and profile of hydraulic structures.

On a functional basis, embankments are promenade, embankments, recreation areas, transport, mooring.

Depending on the design, the embankment can be with a vertical, semi-sloping or sloping profile.

Strengthening the coast with stone

Rice. …. Gabion fortification of the shore

Rice. ... Reinforced concrete fastening of the river bank. Irtysh in Tyumen

Rice. …. Reinforced concrete fastening of the bank slope

Rice. … Vertical masonry shore protection

It is also possible to classify embankments according to other features, for example, natural (landscape, urban), according to the profile of the coastal territory (single-tier, two-tier, etc.).

The listed types are not always found in their pure form. Sometimes certain conditions suggest different combination these types.

The promenade is a pedestrian alley or a landscaped sidewalk along the river. This, as a rule, is a narrow embankment, allowing only local transport access. On such an embankment, gatherings and descents to the water, viewing platforms, gazebos, including green, small architectural forms. In terms of its scale, such an embankment is close to the embankment on a closed reservoir in the park. There may be places for fishing, reading pavilions, stands for newspapers, places for quiet rest, bird feeding grounds, in winter - a ski track.

Embankment - a recreation area is a park area near the river, with a beach or floating swimming pool. Transport entrances in this case should be allowed only for landscaping work. On such an embankment, boat rental, a pier for pleasure river boats can be organized.

Rice. …. River embankment Volga in Yaroslavl

Rice. … Embankment in one of the European countries

Rice. … Embankment r. Volga

Rice. … Verkhnevolzhskaya embankment in Nizhny Novgorod

Rice. … Embankment