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Album “album of standard designs on the use of geosynthetic materials produced by the company \steklonit\. I

Embankment structures in swamps. When filling embankments on slopes with a steepness angle of 1:5 to 1:3, to ensure their stability against shear along the base, ledges from 1 to 4 meters are arranged in them, with a slope of 0.01 - 0.02 in the direction of the fall of the slope , see picture below.

In this case, in the case of a ledge height of 1 meter or less, its wall can be vertical, with a greater ledge height, the slope is given a slope of 1:0.5 - 1:1.5.

Group structures of embankments in swamps are formed taking into account the type of swamps, its depth and the slope of the mineral bottom.

Considering the characteristics of soils, swamps are divided into three types:

Type I - filled with peat and other swamp soils of stable consistency, compressed under load from an embankment up to 3 meters high;

II type - filled with peat and other bog soils of different consistency, including those that are squeezed out under load from an embankment up to 3 meters high;

III type - filled with peat and other bog soils in a liquefied state, squeezed out under load; may have a peat crust - alloy.

The type of swamp is established in the course of engineering and geological surveys with the determination of the physical and mechanical characteristics of the soils of the swamp.

Typical transverse profile of an embankment on slopes with a steepness angle of 1:5 to 1:3 where:

  • a - an embankment with a lower slope height of up to 12 meters;
  • b - detail of an upland ditch with a berm in naturally draining soils;
  • c - lower embankment;
  • g - half embankment - half excavation

The choice of the design profile of embankments in swamps is determined by the condition of not exceeding the permissible elastic settlement and limiting the residual settlement, if possible, by the construction period.

For the construction of embankment structures in swamps, draining soils are mainly used, if such soils are not available in type I and II swamps, it is recommended to use fine or silty sands and sandy soil rocks. In this case, the elevation of the edge of the embankment profile above the surface of the swamp to exclude capillary rise of moisture into the embankment should be applied at least:

- for draining soils 0.8 meters, taking into account the complete removal of peat at the base of the embankment; 1.2 meters with partial peat;

- for fine-grained sands and sandy soils - 2 meters.

According to group decisions, embankments can be built:

- in swamps of type I with an established depth of up to 4 meters with a transverse steepness of the mineral bottom of not more than 1:10;

- on peat bogs of type II up to 3 meters deep, the transverse steepness of the mineral bottom is not steeper than 1:15;

- on peat bogs of type III with a depth of up to 4 meters, the transverse steepness of the mineral bottom is not steeper than 1:20 (type I), not steeper than 1:15 (type II) and not steeper than 1:20 (type III) can be built according to group solutions.

In swamps of type I up to 2 meters deep, according to the condition of elastic settlement, complete removal of peat is envisaged at an embankment height of up to 3 meters. Partial removal of peat in type I swamps is allowed with an embankment height of 2 meters to 3 meters at a certain depth of the swamp up to 4 meters.

With partial removal of peat, the peat is compressed by the value of the calculated settlement S, which can be up to half of its thickness, which should be taken into account in the design.

Depth of peat extrusion hв is assigned from the condition that the total thickness of the bulk soil H + hB + S (above the surface of the swamp and in it, taking into account the estimated draft) is not less than 3.5 meters for roads of categories I-III and 3 meters for roads of category IV, as well as its ratio to the thickness of the compacted peat must be at least 2:1, see figure.

A typical transverse profile of the construction of an embankment up to 3 meters high on peat bogs of type I up to 2 meters deep, the transverse slope of the base is not more than 1:10 with complete removal of peat:

  • a - from draining soils;
  • b - from fine-grained sands, sandy soil rocks;
  • m is the steepness of the slopes of the peat excavation trench (from 1:0 to 1:0.5)

A typical transverse profile of the construction of an embankment up to 3 meters high on peat bogs of type I with a certain depth of up to 4 meters, the transverse slope of the base is not more than 1:10 with partial removal of peat, where:

  • a - from draining soils;
  • b - from fine-grained sands, sandy soil rocks;
  • m is the steepness of the slopes of the peat excavation trench;
  • hB is the depth of peat;
  • S - draft embankment

The steepness of the slopes of the peat excavation trench t is assigned taking into account the method of work in the range from 1:0 to 1:0.5.

With an embankment height of more than 3 meters and a type I peat bog depth of up to 4 meters, peat can be used as a natural base, while the settlement of the embankment by the value S is realized during construction. In this case, it is mandatory to check the conditions for ensuring the permissible elastic settlement of the embankment.

Group solutions for the construction of embankments in type I peat bogs are used when the slope of the mineral bottom is not steeper than 1:10.

The steepness of embankment slopes on draining soils is taken as for typical profiles 1:1.5, and for embankments made of fine or dusty sand and sandy soils, given their sensitivity to the perception of dynamic loads, the upper part is taken with a steepness angle of 1:1.75, and the lower layer with a thickness of 1.0 meters is even more flat - with a steepness of 1: 3, see the figure.

A typical transverse profile of the construction of an embankment up to 3 meters high on type I peat bogs with an established depth of up to 4 meters with a transverse base slope of not more than 1:10 using peat as a base:

  • a - from draining soils;
  • b - from fine-grained sands, sandy soil rocks;
  • S - embankment settlement

Drainage ditches at embankments in type I peat bogs are arranged on both sides at a distance of at least 3 meters from the sole. The cross section of the ditches is assumed to be trapezoidal with a bottom width and a depth of at least 0.8 meters.

Embankments in type II peat bogs with a specified depth of up to 3 meters should be planted on a mineral bottom. At the same time, the vegetation and root cover is cut out, peat with a stable consistency and floating peat with an unstable consistency are removed, and the soil of the ditch at the embankment is poured directly into the water.

Drainage systems in this case are made in the form of pits, the depth of which is taken equal to the thickness of the vegetation and root cover, but not closer than 1 meter, and they are located on both sides, at least 2 meters from the bottom of the embankment.

Group solutions for the construction of embankments in type II peat bogs are used when the slope of the mineral bottom is not steeper than 1:15. The steepness of the slope of embankments for type II bogs is assumed to be the same as for embankments for type I peat bogs, see figure.

Types and characteristics of swamps

Requirements:

Structural solutions for subgrade on roads (with complete peat removal, partial peat removal, without peat removal)

The design of the salary depends on

swamp type

capital stock d.o.

depth of peat

1. the embankment rests on the mineral bottom of the swamp

· This is an embankment loaded onto a miner. the bottom of the swamp by squeezing weak soil to the side

Embankments with complete removal of weak soil from under the base of the embankment and its replacement with high-quality soil

Pile Trestle

2. Mounds supporting. on a peat deposit with measures to improve the building properties of a weak foundation

This is a partial excavation of weak soil

s/n with vertical drains or drainage slots

deep compaction of weak soils with soil piles

chemical strengthening of weak soils

3. Z / n laid directly on the surface of the peat deposit

floating massive embankments

Lightweight embankments

mounds on wooden decks

spec. lightweight structures

part of the s/n located on the surface of the swamp is recommended to be arranged from draining soils (filtration coefficient of at least 2 m per day). Dusty soils are allowed to be used in the above-water part of the embankment, subject to the water-thermal regime.

The construction of the s / n on weak foundations without peat

The use of a floating embankment is limited by the physical and mechanical properties of soft soil, type d.o. and the thickness of the mineral layer.

In this case, the extrusion of weak soil from under the base of the embankment is excluded.

Construction of s/n on weak foundations with partial excavation


Requirements for embankment on weak foundation, safety factor

Fill requirements:

salary stability

stability of the foundation (the intensive part of the settlement of the embankment must be completed before the installation of the coating), the settlement of the embankment is not more than 2 cm per year with a cap.d / o, and not more than 5 cm per year with the installation of lightweight d / o, under such conditions 90% consolidation is achieved the base of the embankment and such a structure will be considered stable

elastic vibrations should not exceed the values ​​established for this type of coating

These three conditions are verified by calculations!

Safety factor

It is determined in the calculation of stability.

Coef. Safety is the ratio of the safe load on the base to the design load on the base.

This coefficient Determined for two load application options: fast circuit (instantaneous) and slow circuit

The fast scheme is characterized by instant filling of the embankment to the desired full height with a margin for draft (K without initial)

Slow scheme - the rate of load transfer corresponds to the rate of increase in the strength of the base (K without con)

K without and early and con. >= 1!

13) Evaluation of the stability of the s / n in the swamps, the phase of soil compaction under the embankment, the dependence curve, the conditions for the stability of the embankment.

The stability of the salary is ensured when the condition Kbez > 1 is met.

Phases of soil compaction under the embankment

Phase 1 - In the first phase, the soil is predominantly compressed under the body of the embankment

Phase 2 - origin. Further compaction and the possibility of lateral shifts

Phase 3 - a sharp subsidence of the soil, which is caused by the bulging of the soil from under the base of the embankment.

Ground stability

To suggest how a weak base under the body of the embankment will behave, it is necessary to carry out a calculation for the presence of a lack of shifts. (this is fucked up, I know, BUT ROCHEV WROTE THIS)
τmax< τ сдвиг

τ max - the highest shear stresses under load from the embankment

τ shear is soil shear resistance.

Calculation scheme

1 – soil resistance to shear at depth Z.

C and γ - assigned depending on soil moisture and loading conditions

2 - a - is valid if the formula is not along the axis of the embankment.

14) The process of formation of ravines, the elements of the ravine, the scheme of the ravine in the plan

The formation of ravines is the result of water erosion.

Water erosion is the process of erosion of soils and easily soluble layers. Erosion processes begin on slopes with a steepness of 2 degrees. Significantly increase with slope steepness from 2 to 6 degrees. And they develop significantly on slopes of more than 6 degrees.

The ravine develops until it reaches layers that are resistant to erosion, or until the drainage basin that feeds it is reduced to such a size that erosion stops.

15) Stages of formation of ravines, longitudinal section of the ravine, its main sections.

Stage 1 - On a steep section of the slope, a pothole (triangular pop. Section) is formed from the actions of flowing water flows. The bottom of the pothole is parallel to the surface of the earth

Stage 2 - The deepening of the pothole, the top of the ravine is formed with a height of 5 to 10 meters. The pothole expands in cross section and becomes trapezoidal. By the end of the 2nd stage, a smooth longitudinal profile or a transit channel is formed in the lower part of the ravine, within which the erosion is balanced by the inflow of soil. At the mouth of the ravine where the water spreads, an alluvial cone is formed.

Stage 3 - there is a further growth of the ravine towards the watershed. The cross section of the ravine is also expanding.

Stage 4 - Final. Attenuation of deep erosion. The ravine stops growing. The slope of the ravine takes on a stable shape and is overgrown with grass. A ravine overgrown with vegetation is called a beam.

Types and elements of earth dams

Requirements for the transverse profile of dams

Almost any local soil can be used for backfilling. Soils are preferable: clays, loams and sandy loams with careful compaction.

Sandy soils should be used for homogeneous dams or for dams with a central impervious prism.

If there is a danger of water filtration through the base of the dam, then in this case an impervious tooth is arranged.

To create soil impervious devices or an embankment at the dam, weak water permeability should be used. Soils. When backfilling a dam from sand, in some cases a screen is made of clay, loam or peat with a degree of unloading of 50%.

If the surface layer at the base of the dam is permeable, then a waterproof core of clay soils with a coefficient Filtration no more than 10 -4 cm/day. Waterproof The core should be buried in the underlying soil. The minimum width of the kernel at the top is assigned. Depending on the production of works, but not less than 0.8 m.

Also in the body of the dam, it is possible to provide Non-ground antifiltrate Devices from a / b; w / w; polymer materials, or an injection diaphragm made of cement. Solution.

The transverse profile of the dam differs from the embankment in more gentle slopes, the laying of slopes depends on the height of the embankment and types of soils + berms are provided on the slopes.

Berms are arranged from the side of the upper slope to create the necessary support, and from the side of the downstream slope to provide service passages.

To protect the upper slope, the following types of fortifications are provided. The upper slope is reinforced with monolithic concrete, a prefabricated reinforced concrete slab.

Lower slope Ukrainian. Sowing grasses or a layer of gravel or crushed stone with a thickness of not more than 15 cm.

Karst. Research methods.

In order to assess the degree and intensity of karst formation, as well as to identify areas unfavorable for road design, it is necessary to conduct a geotechnical survey. Geological survey data provides information about the geological strata, thickness, composition, and degree of fracturing of water-soluble rocks. Information is also collected on the regime of groundwater, on the degree of their aggressiveness and on power sources. The main tasks of an engineer-geologist of surveys:

1. Establish the expected degree of danger for future structures

2. Determine how this affects the environmental situation in the design area

3. Drawing up a forecast for the development of karst for the period of construction and operation of the road

4. To identify the probability of activation of the CP during the operation of the road under the influence of man-made impacts

5. Development of proposed anti-karst measures

To study karst processes, geophysical exploration methods are used:

Electrical exploration

Seismic exploration

Gravimetry

· Micromagnetic filming

When surveying roads, electrical exploration is most often used. It consists in:

o Electrical profiling

o Vertical electrical sounding

o Interwell seismic transillumination

Electrical exploration consists in measuring the electrical resistance of rocks lying at depth. If there is a karst cavity at depth, then the resistance curve changes dramatically.

In places where the karst cavity is fixed, wells are drilled and an analysis of the rocks is taken for research. For the relative safety of the route of the road through karst terrain, it is necessary that the surface layer has a thickness of at least 8-10 meters.

Types of saline soils.

Saline soils - which contain in the upper meter thickness more than 0.3% by weight of easily soluble salts (chloride, sulfuric acid, carbonic salts of Na, K, Mg.

Soils containing in the surface layers to a depth of 1-2 m in a free state more than 1% of easily soluble salts are called solonchaks. They are formed as a result of pulling up to the surface through the capillaries of groundwater containing soluble salts. In salt marshes there are salts: NaCl, MgCl 2, NaNO 3, KSO 4. The amount of such salts in the upper layers can reach 15-25%.

Solonchaks are distinguished by external signs:

Wet and crusty

Such solonchaks are formed in areas with a high standing of groundwater. Wet solonchaks are weak soils, therefore they can cause subsidence of the earth sheet, as well as bulging of the soil from under the base of the embankment.

plump salt marshes

Loose layer with salt crystals. They lie under a thin clayey crust.

· Takyr-like.

Saline soils are most often located in low relief areas with a close standing level of saline groundwater.

There are 4 main types of salt accumulation in soils:

Sulphate-soda (typical for the forest-steppe). The salt content in the upper horizons ranges from 0.5 to 1%

· Chloride-sulfate (typical for the steppes). Salts 2-3%

Sulfate-chloride (semi-deserts). Salts 5-8%

Chloride (desert) salts over 8%

Forms of sandy relief.

The main feature of sandy deserts is unstable relief. The movement of sand particles depends on the wind speed, and on the size of the particles. The higher the wind speed at the earth's surface, the larger particles it moves.

Characteristic forms of sandy relief:

1) Dunes - single or grouped hills 3-5 m high and up to 100 m wide. in plan they look like a crescent moon. The windward slope of the dune is gentle, the steepness is 1:3, 1:5. The leeward has a natural slope of 1:1, 1:1.5.

This form of sandy relief is the most unstable and easily moved by the wind.

2) Dune chains. They are formed in areas where winds dominate, which change their direction 2 times a year. They are located perpendicular to the direction of the winds, have a width along the top of 10-20m and a length of up to 2km. Height up to 15m.

3) Sandy ridges. Formed by seasonally changing winds. They stretch parallel to the prevailing wind direction. They have a length of 2-3 km and are located at a distance of 150-200 m from each other. sandy ridges are the final form of sandy relief development.

4) Hilly sands. Vegetated sandy hills of irregular geometric shape. Height 6-8m. The steepness of the slopes is approximately the same in all directions.

Sand mobility is affected by:

1. Wind speed

2. Granulometric composition

3. Humidity and salinity of soils

4. The degree of fixation of the sandy surface by vegetation.

If the surface is more than 35% covered with vegetation, then such sands are considered immovable and have a stable topography.

Sand transfer laws.

The wind flows around the unevenness of the sandy relief, this is accompanied by the formation of areas of local increase in the flow velocity. Thus, zones of turbulence and calm are formed.

In the swirling zone, sand is dispersed, and in the damping zone, it is deposited. The grains of sand are carried in the direction of the wind, rise along the slopes of sandy hills and are deposited in a calm zone. As a result, sand hills are constantly moving, and such sands are called mobile.

Features of mountain areas

Survey, design and construction of mountain roads presents significant difficulties due to:

complex terrain,

Steep unstable slopes

Overcoming a large difference in height at a short distance

During the construction of mountain roads, it is necessary to develop large volumes of rocky soils. In this case, it is necessary to perform explosive methods of work.

· Also, due to the instability of landforms and bedding of rocks, it is required to install retaining and envelope walls.

· Under unfavorable conditions (landslides, rockfalls), it is necessary to build complex special structures that ensure the stability of the subgrade.

The need to guide the track along the slopes leads to its large elongation and rise in price

Influence of climatic factors when designing a road in a mountainous area:

1. In mountainous regions, vertical zonality is manifested, namely, significant differences in climatic conditions at different heights above sea level.

2. The air temperature in the mountains is lower than in the valleys. Lowering the temperature by 0.5 degrees per 100m of altitude. Cases of inverse temperature distribution are also observed. Closed valleys or lowlands collect denser cold air (inversion).

3. The air temperature in the mountains also depends on the exposure of the slopes to the cardinal points. The south and southwest slopes are more quickly freed from snow and dry out. On the northern slopes, snow can persist until mid-summer.

4. The amount of precipitation increases as the height rises 40-60mm per 100m of height. the intensity of precipitation increases sharply in summer.

5. pressure decreases with height

6. At high altitudes of 3000-4000m, frequent strong winds up to 30m/s are observed.

Mountain slope stability:

In mountainous areas, the soil cover is thin. On steep slopes, bedrock comes to the surface, or is covered from above with weathering products. Sedimentary rocks, composed of layers, often occur in the form of folds. The fold facing downward is a syncline, and the top is an anticline. Layers of limestones and sandstones can be separated by layers of clay. When such layers are saturated with water, deformations, such as landslides and shifts, are possible.

A variety of bedding applied to roads:

1) horizontal bedding

2) dip of layers towards the slope

3) falling layers inside the slope

4) reclining bedding of younger breeds.

Sedimentary rocks are especially dangerous when cutting slope layers with slopes of cuts, in the thickness of which clay layers can occur. Igneous rocks are stronger and more stable in slopes, in almost any direction of layering. In the surface layers, igneous rocks are more often fractured, therefore, when laying a road route, it must be taken into account that processes of stability loss as a result of weathering, as well as tectonic movements, are possible.

The main forms of violation of the stability of slopes (and slopes):

1) shedding of weathering products from the slopes

2) collapses of individual stones with the formation of ledges in fractured rocky rocks

3) melting of the surface layers as a result of waterlogging

4) plastic sliding of slopes at a rate of several cm per year

5) collapse of a part of the homogeneous soil stratum, with an excessive steepness of the slope

6) displacement of part of the soil along the underlying surfaces as a result of loss of adhesion in the contact zone

7) collapse with the formation of a vertical crack and lateral displacement of the detached block as a result of squeezing out weak underlying layers

46. ​​Features of the design of the route plan in mountainous areas, characteristic stages.

According to the design conditions, the characteristic zones of mountainous regions are distinguished:

1) foothill areas

2) valleys of mountain rivers

3) mountain slopes

4) watersheds (or saddles)

The direction of the laying of mountain roads is determined by the location of the mountain ranges, which are the watersheds of the basins of large rivers. The transition of the road from one river basin to another is possible only through the lowering of mountain ranges (cols).

The course of laying the road (stages): first along the valley of a mountain river, then up to its sources, then climbing the mountain slopes to the saddle, then crossing the pass section to the valley of another river.

Tunnels on mountain roads

Tunnels cases:

1.When crossing short rock outcrops;

2. On the highlands. pass. plots;

3. With the aim of reducing. the length of the route instead of its development along the slopes;

Devices for two-tier tunnels. Banding on other categories of roads. For the 2nd category 3 pos. movement tolerance When designing preferred plan. give straight. uch-kam. If necessary, R curves in the plan for a / d tunnels should be at least 250m. 150m in exceptional cases. Most Sold slope project.line tolerance. keep in the tunnel if its length is less than 300m. Tunnel profile up to 300m long odnoskat. With a tunnel length of more than 300 m - a double slope. Slopes not less than 3% and not more than 40%. With a tunnel length of up to 500 m, the allowance. slope up to 60%. In tunnels, drainage must be provided at the approaches to the tunnel. FC in tunnels design. with c / w monolithic coating, or with reinforced. a/b cover. It is necessary to implement ventilation inside the tunnel of natures. or mechanical. way. With a tunnel length of more than 400 m obligatory. morning mechanical ventilation. Also, with a tunnel length of more than 1000 m, it is necessary to speaker set More than 200m - barrage alarm.phone. connection foreseen. Services (emergency) passages on each side with a width of 0.5 m.

Types and characteristics of swamps

Swamp - excessively moistened areas of the earth's surface, on which water stagnates most of the year. The swamps are divided into upper and lower.

riding - are formed with frequent precipitation, are formed on watershed areas and gentle slopes. The formation of raised bogs most often occurs in spruce forests, moss appears and then it develops into white moss - sphagnum. The peat-forming process in the raised bog leads to a change in the water balance of the surface of the layers, to a gradual change in vegetation in this area, which in turn leads to an increase in the peat layer. The middle of the swamp can rise to 6-8 m.

grassroots - are formed as a result of overgrowth of water bodies (lakes and slowly flowing rivers). Overgrowing occurs from the coast to the middle, marsh vegetation appears near the coast. Dying plant remains raise the bottom of the reservoir and lead to the formation of silt. Gradually, the surface overgrows and forms a floating mass - an alloy (consists of rhizomes, plants and moss).

Engineering classification of swamps

Type I - filled with bog soils, the strength of which in the natural state makes it possible to erect an embankment up to 3 meters high without the process of lateral extrusion of weak soil.

3) Choice of route layout in wetlands (basic requirements)

Requirements:

It is advisable to bypass the swamp if it is not with a significant elongation of the route or its sinuosity

· Crossing swamps in the shortest direction, also at the narrowest point and at the least deep, where the value of the swamp bottom is high.

Crossing the swamp perpendicular to the flow of water

· When crossing rafted swamps, one should avoid places with steep slopes of minera. bottom.

When crossing swamps with roads, preference is given to type I swamps

· The decision on the choice of route options is based on a technical and economic comparison.

- excessively moistened land areas with a kind of marsh vegetation and a layer of peat of at least 0.3 m, therefore, they are characterized by a difficult exchange of gases. Marshes usually contain from 87 to 97% water and only 3-13% dry matter (peat).

With a lower peat capacity or its absence, excessively moistened areas are called wetlands.

Swamps are formed when water bodies become overgrown or when the area becomes swampy.

The main way of formation of swamps is swamping, which begins with the appearance of periodic, and then constant waterlogging of soils. The climate contributes to this. Excess moisture due to an abundance of precipitation or low evaporation, as well as a high level of groundwater, the nature of the soil is poorly permeable rocks; "permafrost", relief - flat areas with shallow drainage or depressions with slow flow; prolonged floods on rivers, etc. Forests die under conditions of excess moisture, which means anaerobic conditions and oxygen starvation, which contributes to greater waterlogging due to a decrease in transpiration.

Water-loving vegetation settles on waterlogged lands, adapted to a lack of oxygen and mineral nutrition - moss, etc. Moss sod, which absorbs and retains moisture well, resembling a wet sponge, contributes to even greater waterlogging of the land. So in the future, it is the vegetation that plays the leading role in swamping. In conditions of lack of oxygen, incomplete decomposition of plant residues occurs, which, accumulating, form peat. Therefore, swamping is almost always accompanied by peat accumulation.

The most favorable conditions for the accumulation of peat exist in the forests of the temperate zone, especially in Western Siberia, where, within the forest-bog zone, swampiness sometimes makes up more than 50% of the territory, the peat thickness is 8-10 m. To the north and south of the forest zone, the thickness of the peat deposit decreases: to the north due to a decrease in the growth of plant mass in a cold climate, to the south - due to more intensive decomposition of plant residues in a warm climate. In a hot humid climate, a huge increase in biomass is compensated by an intensive process of decay of dead plants, and there are few swamps, although the evergreen equatorial forests are waterlogged.

The structure of the peat deposits of swamps that have arisen on the site of lakes or dry valleys is different. Peatlands formed as a result of the swamping of lakes have lake silt, sapropel, under a layer of peat, and when the land becomes swamped, peat lies directly on the mineral soil.

Bogs develop in various climatic conditions, but are especially characteristic of the forest zone of the temperate zone and tundra. Their share in Polissya accounts for 28%, in Karelia - about 30%, and in Western Siberia (Vasyugan) - over 50% of the territory. Swampiness sharply decreases in the steppe and forest-steppe zones, where there is less precipitation, and evaporation increases. The total area occupied by swamps is about 2% of the land area of ​​the Earth.

swamp types

According to the nature of the water supply and vegetation, the swamps are divided into three types: lowland, upland and transitional.

lowland swamps are formed on the site of former lakes, in river valleys and in depressions that are permanently or temporarily flooded with water. They feed mainly on groundwater rich in mineral salts. The vegetation cover is dominated by green mosses, various sedges and grasses. Birch, alder, and willow appear on older swamps. These swamps are characterized by weak peat content - the thickness of peat does not exceed 1 — 1 .5 m

Raised bogs are formed on flat watersheds, feed mainly on atmospheric precipitation, the vegetation is characterized by a limited species composition - sphagnum mosses, cotton grass, wild rosemary, cranberry, heather, and woody - pine, birch, less often cedar and larch. The trees are very depressed and stunted. Sphagnum moss grows better in the middle of the marsh massif, on the outskirts it is oppressed by mineralized waters. Therefore, raised bogs are somewhat convex, their middle rises by 3-4 m. The peat layer reaches 6-10 m or more.

transitional swamps, or mixed represent a transitional stage between lowland and upland. In lowland swamps, plant residues accumulate, the surface of the swamp rises. As a result, groundwater rich in salts ceases to feed the swamp. Herbaceous vegetation dies off and is replaced by mosses.

Thus, low-lying bogs turn into raised ones, and the latter are then covered with bushes or meadow vegetation, turning into upland meadows. Therefore, in nature, moss or grass swamps are rarely found in their pure form.

Bogs are of great economic importance. Thus, peat bogs are a source of fuel for industry. The first thermal power plant in the world operating on peat was built in Russia in 1911 (in Elektrougli).

Lowland bog peat is a good organic fertilizer. Therefore, partially lowland swamps are drained and turned into fertile lands. But not all swamps are subject to drainage, some of them must be preserved so as not to disturb the relationships that have developed in nature.

Marshes humidify the air of the area, are the habitats of valuable plant species (cranberries, cloudberries, blueberries) and habitats of many species of animals, especially birds, are natural reservoirs of water that feed the rivers.

This article will consider one of the most common natural formations, which is a waterlogged area of ​​the earth's surface with a layer of peat and peculiar plant forms characteristic only for such areas, adapted to conditions with a lack of oxygen, with poor water flow and with excess moisture.

Various types of swamps with their brief characteristics will be presented here.

general information

There are 3 main signs of swamps:

  • Excess and stagnant water.
  • The presence of specific, typical for swamps, vegetation.
  • Peat formation process.

Wetlands are commonly referred to as areas where plant roots cannot reach the mineral soil.

Education

Before we find out what the main types of swamps are, let's find out how they are formed.

The formation of such areas requires a constant excess of moisture in the soil and on its surface, as well as a weak water exchange (including with groundwater). In turn, the lack of oxygen caused by excess moisture makes it difficult for air to enter the soil, and therefore there is insufficient decomposition (or oxidation) of the remains of dying vegetation, and peat is also formed. The latter is a soil substrate with a high water content. It consists entirely of decomposed plants. Peat is distinguished by varying degrees of decomposition. For example, a decomposition rate of 70% means that 70 percent of dead plants have decomposed, and 30 percent have not. This type of substrate has excellent water-holding capacity, so it has a rather high water content (about 97% of the total volume).

According to the forms and conditions of nutrition, low-lying (in a different way eutrophic), transitional (mesotrophic) and riding (oligotrophic) are distinguished, respectively, having a concave, flat and convex surface shape.

By lowland (eutrophic) swamps are meant, located in depressions, with soil moistened by surface and groundwater, rich in mineral salts. Horses mainly feed on precipitation from the atmosphere, which is not very rich in mineral salts. Transitional swamps belong to the intermediate group.

According to the vegetation prevailing in the area, forest, grass, shrub and moss types of swamps are distinguished. According to the microrelief - bumpy, flat, convex. Marshes are the most waterlogged swamp areas.

Russian swamps

We will consider the types of swamps in Russia a little lower. In the meantime - general information.

The area of ​​swamps in Russia is approximately 1.4 million square kilometers. km (approximately 10% of the area of ​​the entire territory of the country). According to rough estimates, they contain about 3000 cubic meters. m of static natural water reserves.

Swamps are quite complex. They consist of interconnected biotopes, which are characterized by strong moisture, the presence of a kind of moisture-loving vegetation and the accumulation of various organic residues in the form of silt or peat. Under the conditions of different Russian climate, relief, and depending on the underlying rocks, different types of bogs develop, each of which differs in the characteristics of the peat deposit, the conditions of water supply and its runoff, and the characteristics of vegetation.

There are the following types of nutrition of the swamps of Russia: lowland, upland and transitional.

About the nature of nutrition

By characterizing the nutritional conditions, we mean the modern surface of the swamp and the presence of that upper layer of the substrate where the roots of plants are located. For each type of swamp, their food sources are presented a little higher.

Excess moisture is the main symptom of any swamp. It causes the emergence of specific species of animals and vegetation, as well as peculiar special conditions of humification, which in a temperate climate usually lead to the incomplete decay of plant residues and the formation of peat.

Geographical distribution of swamps in the Russian Federation

Russian swamps are common in almost all natural zones, but mainly in drainless, excessively moistened depressions. Most of them are concentrated in the central regions and on

The most wetlands in Russia are the tundra and the taiga zone. The types of swamps here are very diverse. Waterlogging in some areas of the tundra is 50%. In the taiga zones, approximately 80% of all are concentrated. In the European part of Russia, the most swampy are the Vologda, Leningrad regions and the Republic of Karelia (approximately 40%).

The taiga of Western Siberia is swamped up to 70 percent. A huge number of swamps in the Far East, mostly in the Amur region.

Distribution of swamps by type

The types of swamps in Russia are territorially distributed unevenly. Horses occupy half of the total swampy area, and they predominate in the northern regions. Lowlands make up less than half (about 40%) of the area of ​​all swamps. Very small areas are occupied by marshes of the transitional type (10%).

Lowland swamps are mostly fed by river or groundwater, and they are mostly found in arid regions. And these are the valleys and deltas of large rivers. Upland bogs are mainly fed by atmospheric precipitation, and they are more often found in the taiga and tundra zones of Eurasia. The main part (84%) of peat areas is located in the Asian part of Russia.

And what type of swamp prevails in the North? Lowland swamps in the west of Siberia occupy 42%. Most of the peat lands (about 73%) are confined to the area of ​​territories with permafrost.

Vegetation cover

In the lowland swamps, the following plants predominate: downy birch, willow, pine and spruce. From herbs, sedge is predominantly found here, and from cereals - reeds and reeds. Mosses mainly grow green mosses.

Transitional bogs are characterized by birch and pine (in Siberia - Dahurian and Siberian larches, cedar), as well as willow (slightly less often than in lowland bogs). Of the grasses, the same vegetation is common here as in the lowland swamps, but not in such significant quantities. Most often here you can find alpine sedge, reed grass, bottle sedge and woolly-fruited sedge. There is also vegetation characteristic of raised bogs.

On upland bogs there are pine (cedar is mixed with it in Siberia) and Dahurian larch. There are no shrubs here at all, but the heather group prevails in these places: cassandra, heather, wild rosemary, blueberries and cranberries. Here, one-headed cotton grass (a herbaceous plant), which forms large hummocks, sods, grows abundantly and is widespread in such places. You can often find cloudberries with sundew. Mosses here are represented only by sphagnum.

Thus, according to the nature of peat and vegetation, one can also judge (as noted above) what type of swamps is.

Concluding on environmental issues

In recent years, more and more negative processes have arisen in connection with the excessive, destructive exploitation of swamps. First of all, this is pollution, excessive water intake from the soil and mass extraction of peat. Drainage and plowing, violation of the hydrological regime during the construction of roads, gas and oil pipelines and other structures also played an important role in this.

Drainage of swamps often leads to peat fires, land degradation and loss of biodiversity. All work must be carried out carefully, with the obligatory preservation of most of the wetlands. Be sure to follow the rules of maintaining ecological balance in nature.

Wetlands occupy about 10% of the territory of our country. Russia accounts for 3/4 of the swamps of the globe, in other words, for each inhabitant of the Russian Federation, there are about 1 ha of swamps. Swamps are usually called places with difficult surface and internal runoff, occupied by natural deposits of highly porous water-saturated soils. The swamp boundary is considered to be from a depth of 0.5 m.

The fundamentals of a scientific solution to the problem of building roads through swamps were developed in the 30s of the last century by N.P. Kuznetsova. Her works together with the works of A.A. Arsenyeva, L.A. Bratsev have not lost their relevance at the present time. In railway construction, similar tasks were solved by K.S. Orduyants, N.N. Sidorov, G.M. Shakhunyants and others. Scientists from MADI, SoyuzdorNII, BeldorNII and others made a significant contribution to the design and construction technology of the subgrade in the swamp.

Despite scientific developments, the technical level of road construction in wetlands is slowly improving. Design organizations do not sufficiently take into account modern achievements of science, do not orient builders towards the use of economical structures and technological methods mastered by world practice. Peat removal is often laid without sufficient justification, as a result of which the average cost of 1 km of subgrade through swamps is 3-5 times higher than under normal conditions.

According to food sources, swamps are divided into:

Lowland, fed by groundwater. These marshes contain well-decomposed dense woody, grassy, ​​or moss peat;

Riding, formed as a result of land swamping. Peat is characterized by a low degree of decomposition and low density;

Transient - mixed soil and atmospheric nutrition. Peat in terms of properties occupies an intermediate position between lower and raised bogs.

According to their structure, swamps can be divided into three types with some assumption:

Type I - swamps, filled to the bottom with peat of a stable consistency;

Type II - swamps filled with weak peat of unstable consistency (sapropel);

Type III - swamps with a peat layer floating on water or sapropel (floating).

Embankments in swamps, depending on the type of swamp, the technical category of the road, can be erected:

Without peating with dumping directly on the surface of the swamp;

After complete or partial peat removal;

With backfilling on a layer of peat, followed by planting an embankment on the mineral bottom of the swamp;

On the surface of the swamp after the installation of drainage slots or vertical drains.

The design of the subgrade and the method of work are selected depending on: the density of peat, the depth of the swamp, the technical category of the road, the availability of mechanization, taking into account the reduced costs E pr.


E pr = (WITH 1 -WITH 2)+(E 1 -E 2 /E n)+H p(T 1 -T 2 /T 1)+Etc(T 1 -T 2)+(S 2 P 2 -S l P 1)+E n(F 1 T 1 -F 2 T 2), (4.2.1)

Where WITH 1 , WITH 2 - estimated cost of road construction for the first and second options;

E 1 , E 2 - average annual operating costs for the first and second options, rub.;

E n- normative coefficient of efficiency;

H p- semi-fixed overhead costs, according to the first option;

T 1 , T 2 - duration of construction according to the first and second options, years;

Etc- average annual profit in the transport industry due to the commissioning of the highway, rub.;

S l , S 2 - the amount of damage from the emergency exit of the facility for the first and second options, rub.;

P 1 , R 2 - the probability of accidental destruction for the first and second options for the service life of the structure;

F 1 , F 2 - the average size of fixed production assets and working capital for the first and second options.

The main production assets include machinery, equipment, industrial buildings, and defense assets include raw materials, fuel, tools, and spare parts.

The calculation is made for the entire standard period of operation of the road for the entire length of the passage through the swamp.