RU2149947C1 - Method for stabilization of washing-away banks of tundra rivers - Google Patents

Abstract

FIELD: hydraulic engineering. SUBSTANCE: method is intended for protecting banks of tundra rivers from thermal erosion and washing away. According to method, prepared is ground base of bank slope with subsequent placing of hard surfacing. Prior to placing of hard surfacing, thermal-insulating material is laid on ground. Protective surfacing covers interval found between horizon of start of intensive heating of water at reduction stage of high water and minimal boundary-mark of water horizon. Upper end and lower end of surfacing are water-proofed by means of clay clamps. Application of aforesaid method allows for prevention of destruction of banks of rivers located in conditions of spreading permafrost rock matter in tundra zone. EFFECT: higher efficiency. 1 dwg

Description

 The invention relates to the construction of hydraulic structures, in particular for protecting the banks of tundra rivers from thermoerosion and erosion.

 There is a method of protecting coasts from incoherent soil from wave action, including dumping of incoherent beach-forming material on a water edge in the form of a prism (AS USSR N 1767070, class E 02 B 3/12, 3/04. Bull. 37, 1992) .

 The disadvantage of this method is the fragility of the protection of the coast, especially in the conditions of the spread of permafrost in the tundra zone.

 There is a method of protecting coasts from incoherent soil from erosion under the influence of currents and wind waves, including laying concrete or reinforced concrete clothing on a prepared base in the form of a sand layer laid on a slope along the entire height of the coast (Construction in the aquatic environment: Reference, E.G. Godes, PM Narbut, L .: Stroyizdat, 1989, p. 420).

 The disadvantage of this method is the inability to prevent the destruction of river banks located in the conditions of the spread of permafrost in the tundra zone.

 The technical result of the present invention is to prevent the destruction of river banks located in the distribution of permafrost in the tundra zone.

 The technical result is achieved by the fact that in the known method of strengthening eroded banks of tundra rivers, including preparing a soil base for the bank slope, laying a hard coating, heat-insulating material is placed on the ground before laying a hard coating, and the protective coating covers the interval between the beginning of the intensive heating of water in decline floods and a minimum water horizon, and the upper and lower ends of the coating are waterproofed, for example with clay locks.

 The invention made it possible to achieve a result that satisfies the long-existing need to strengthen the banks of tundra rivers, which are destroyed mainly by thermal erosion, which specialists have not been able to obtain for a long time.

 The invention is illustrated in the drawing.

 The method includes laying a hard coating 1 (concrete slabs, flexible concrete structures, poured concrete, etc.) on the prepared slope of the shore, and before laying the hard coating on the ground put a layer of water-resistant heat-insulating material 2, while the protective coating covers the interval concluded between the horizon of the beginning of intense heating of water at the drop of the flood and the minimum low-water horizon of the water, and the upper and lower ends of the coating are waterproofed, for example with clay locks 3, from penetration of more than loi water to the shore of frozen soil.

 The underwater part of the coastal slope is protected by one of the well-known methods used for thawed soils: stone sketches, crushed stone 4, laying flexible gabions, etc.

где H_н - глубина протаивания грунта берега под действием тепла воды, м, определяемая натурным измерением по глубине вырабатываемой ниши в нижней части берега или по известным формулам для расчета границы протаивания мерзлых грунтов;
λ_из - коэффициент теплопроводности теплоизолирующего материала, ккал/м•ч•^oC (для пенопласта λ₀ = 0,05 ккал/м•ч•^oC);
λ_м.г - коэффициент теплопроводности мерзлого грунта, ккал/м•ч•^oC, определяется натурными измерениями или по справочникам и таблицам соответствующих нормативных документов.The thickness of the insulator is calculated by the formula

where H _n - the depth of thawing of the soil of the coast under the action of heat of water, m, determined by the full-scale measurement of the depth of the generated niche in the lower part of the coast or by known formulas for calculating the boundary of thawing of frozen soils;
λ _of is the coefficient of thermal conductivity of the insulating material, kcal / m • h • ^o C (for foam λ ₀ = 0.05 kcal / m • h • ^o C);
λ _mg is the coefficient of thermal conductivity of frozen soil, kcal / m • h • ^o C, is determined by field measurements or according to the directories and tables of the relevant regulatory documents.

 Works construction, constructed by the proposed method, as follows.

 With the rise, peak, and most of the decline in flood water levels on tundra rivers, the water temperature is close to zero. Soil of the coast at this time does not melt and almost does not erode. In the second half of the decline in flood levels, the water begins to warm up intensively and thaw the coastal soils at the border of their contact. The melted soils of the banks of the tundra rivers acquire a liquid-plastic consistency and are easily washed out by water, forming a niche in the lower part of the shore.

 With the shore protection structure constructed by the proposed method, water, despite an increase in its temperature, does not thaw the soil of the shore, because this is prevented by the heat insulator, and the soil is not washed out due to the structure, and the hard coating prevents the mechanical destruction of the heat insulator. As a result, the frozen shore in the upper part of the slope, where the level of cold water reaches at the maximum of the flood, itself resists erosion, and in the lower part of the slope, starting from the level horizon at the decline of the flood, when the water begins to warm up intensively, and until the low-water horizon, the shore is protected from thermoerosion and from mechanical stress erected by this method construction.

Claims (1)

 A method of strengthening eroded banks of tundra rivers, including preparing the soil base of the bank slope, laying a hard coating, characterized in that before laying the hard coating, heat-insulating material is placed on the ground, with a protective coating covering the interval between the horizon of the beginning of intensive heating of water at a drop in flood and a minimum low water horizon, and the upper and lower ends of the coating are waterproofed, for example, with clay locks.