RU160273U1 - PERMANENT FREEZE BUILDING - Google Patents

Abstract

1. A permafrost building, containing a foundation located on the foundation soils, a body placed on the foundation, and a cooling system, and the foundation soils contain, at the end of the warm season, a thawed zone located above and a frozen zone below, while the building has a rectangular shape with a length of "l" and a width of "b", characterized in that it contains a thermal insulation layer equivalent to a foam glass with a thickness of "Δ", located between the building’s building and its foundation, and the soil cooling system is made in in the form of hollow pipes with an inner diameter of "D", plugged at both ends by covers and partially immersed in the soil in a vertical position, the pipes being located on the outside of the building along its side with a length "l" with a distance "c" between each other and at a distance " a "from the wall of the building, and also along one pipe at the ends of the building in their middle, while the depth of the melt zone from the level of the natural surface of the soil in the zone of hollow pipes is" h ", and in the center of the building is" h ", where d is the distance between opposite rows of hollow pipes, m; D- conditional the inner diameter of the hollow pipe, m (assumed equal to 1.0 m); m is the correction factor taken equal to (0.8 ÷ 1.2), b / r; h, H are the height of the aboveground and underground parts of the hollow pipes, m.2. The building according to claim 1, characterized in that the hollow pipes contain a coaxially located pipe of diameter d inside the cavity, having side cutouts of area S in the upper and lower ends,

Description

The utility model relates to the field of construction, namely to structures being erected in permafrost areas.

The building on permafrost is known (Foundations of structures on frozen soils in Yakutia / K.F. Voitkovsky, P.I. Melnikov, G.V. Porkhaev, etc. - M .: Nauka, 1968. - P. 66). The building is a structure erected on a heat-insulating bedding. The advantage of this design is to minimize the warming effect of the building on the permafrost soils of the base. The design drawback is the lack of cooling effect on the soil of the base, which can lead to the thawing of the deep layers of the base soil and deformation of the structure in the case of the thermal effect of adjacent territories.

The building on permafrost is known (Gapeev S.I.Hardening of frozen foundations by cooling. - 2nd ed., Revised and enlarged. - L .: Stroyizdat; Leningradskaya otd., 1984. - 156 p.). The building is a structure on a strip foundation, surrounded by cooling units, which help to preserve the frozen state of the soil of the base with lowering their temperature. This feature is the advantage of this design. The disadvantage is a shorter service life of the cooling units than the main structure, which necessitates their constant replacement during the entire period of its operation.

The objective of this technical solution is to increase the reliability of the cooling system of the structure by combining thermal insulation and deep cooling installations, in which the total effect is higher than the sum of the effects of individual measures

To achieve the specified technical result, the permafrost building contains a foundation located on the foundation soils, a housing placed on the foundation, and a soil cooling system. The base soils contain, at the end of the warm season, a thawed zone located on top and a frozen zone on the bottom. The building has a rectangular shape with a length of "l" and a width of "b" and contains a layer of thermal insulation equivalent to foam glass with a thickness of "Δ", located between the building’s building and its foundation. The soil cooling system is made in the form of hollow pipes with an inner diameter “D”, plugged at both ends with covers and partially immersed in the soil in a vertical position, the pipes being located on the outside of the building’s body along its side with a length “l” with a distance “c” between themselves and at a distance “a” from the wall of the building, as well as one pipe at the ends of the building in their middle, while the depth of the melt zone from the level of the natural surface of the soil in the zone of hollow pipes is “h _B ”, and in the center of the building “h _C ". The main parameters are related by the following relationships:

d = b + 2a, m;

D = m ² · D _C , m;

H = m20D, m;

h = 0.15m · N, m;

, м;

, m;

, б/р (Δ≤0,5 м);

, b / p (Δ≤0.5 m);

s = 0.3 md, m;

l≥b, m

where d is the distance between opposite rows of hollow pipes, m;

D _C - conditional estimated internal diameter of the hollow pipe, m (assumed equal to 1.0 m);

m - correction factor, taken equal to (0.8 ÷ 1.2), b / p;

h, H - respectively, the height of the aboveground and underground parts of the hollow pipes, m;

, м².In addition, hollow pipes may contain a coaxially located pipe with a diameter of d _K inside the cavity, having side cutouts of area S in the upper and lower ends, with d _K = 0.7D, m;

, m ² .

The essence of the utility model is illustrated by drawings, where

in FIG. 1 shows a diagram of the device (section aa in Fig. 2);

in FIG. 2 - section BB in FIG. one;

The permafrost building (Fig. 1) contains a foundation 1 located on the soils of the base 2 and a casing 3 located on the foundations 1 and cooling soils of the system 4, and pounds of the base 2 contain, at the end of the warm season, the melt zone 5 located on top and below - frozen zone 6, while the building has a rectangular shape with a length of "l" and a width of "b" and contains a thermal insulation layer 7 of a thickness of "Δ" located between the building 3 and its foundation 1. The cooling soil system 4 is made of hollow pipes with inner diameter m “D”, muffled at both ends by covers and partially immersed in soil 2 in a vertical position, the pipes being located on the outside of the building’s casing 3 along its side with a length “l” with a distance “c” from each other and at a distance “a” from walls of the building, as well as one pipe at the ends of the building in their middle. Depth of thawed zone 5 in vivo, i.e. Before the construction of the building, it can exceed the thickness of the active layer and is characterized by a border of 8. After the construction of the building under it, the boundary of the thawed and frozen zones changes and is characterized by curve 9. The depth of the thawed zone from the level of the natural surface of the soil in the zone of hollow pipes is “h _B ”, and in the center buildings "h _C ". In addition, the cooling system forms a frozen core 10. The main parameters are interconnected as follows:

where d is the distance between opposite rows of hollow pipes, m;

D _C - conditional estimated internal diameter of the hollow pipe, m (assumed equal to 1.0 m);

m - correction factor, taken equal to (0.8 ÷ 1.2), b / p;

h, N - respectively, the height of the aboveground and underground parts of the hollow pipes, m;

, м².In addition, the hollow pipes may contain inside the cavity a coaxially arranged pipe with a diameter d _K having side cutouts of area S at the upper and lower ends, with d _K = 0.7D, m;

, m ² .

Formulas (1-8) were derived on the basis of the following assumptions.

The distance “d” between the thermal supports and the ratio “n” of the calculated and maximum thermal insulation thickness were taken as the main parameters in thermophysical calculations (see the Appendix to this description). Moreover, “H” was assumed to be constant and equal to 20 m. This value is recommended for use in practice. Formula (5) is obtained on the basis of three-dimensional thermophysical calculations (see the Appendix to this description). Coefficient "m" takes into account a possible change in height "H". The introduction of the value of “m” in the square in formula (2) means that when the diameter of the thermal support changes, the cooling effect changes nonlinearly (to a lesser extent, see the monograph Passek V.V., Petrov V.I. Thermo supports - an effective and promising type of structure on permafrost. - M: TSNIIS, 2009. - 104 s). Relation (7) was taken as the initial condition in thermophysical calculations and in the derivation of formula (5).

The permafrost building works as follows.

The load from the structure is perceived by the foundation; the thermal regime of the soils of the base 2 is supported by a combination of the cooling soil of the system 4 and thermal insulation 7.

Cooling is based on air convection in the pipe cavities of system 4 in winter and occurs as follows. Cooled in the aboveground part of the cavities of the cooling system 4, the air goes down and gives off cold to the ground through the walls of the pipes of the cooling system 4, after which it rises up to the aboveground part, where it is again cooled, etc. In the presence of coaxial inserts, air flows are separated: warm ascending ones move inside the coaxial insert, and cold descending flows inside the cavity formed by the gap between the walls of the pipe of the cooling system 4 and the coaxial insert. In the summer, convection ceases, and heat does not enter the soil.

Thermal insulation 7 plays a passive role: it reduces the intensity of heat fluxes from the building into the ground. The size of thermal insulation is taken into account due to the coefficient “n” in formula (5). Thermal insulation allows you to adjust the depth h _C talik, if necessary, bringing it to almost zero.

The essence of the proposed technical solution is based on the possibility of using conventional buildings on permafrost without aired underground due to the combination of thermal insulation under the building and thermal supports located along its perimeter. Such a system can be rational with a width of "d" not exceeding a certain value of d _max .

A feature of such a system is the presence of frozen “humps” in the area of thermal supports with a depth of thawed layer “h _B ”, while h _B <P _EST , i.e. depths of the active layer in vivo.

Thermo supports also form a hard-frozen core 10, providing the bearing capacity of the thermo supports along the side surface and at the end. For parameters specified by formula (5), the hard-frozen core 10 under the center of the building closes, providing the calculated parameters of the talik, i.e. a guarantee that it will not increase more than the dimensions defined by formula (4).

The foundation may be:

1) from a beam on humps;

2) from the plate, taking into account its precipitation, which is fixed by the cooling system (Fig. 1). Moreover, the depth h _C talik is fixed by the formula (4);

3) on short piles, reinforcing the foundation 1;

4) but the most important thing is that the cooling devices themselves (thermal supports) can be used as the main supporting structural element - the foundation plate 1 can be supported on them.

Improving the reliability of the cooling system of a structure is achieved through a combination of thermal insulation and deep cooling systems. The effectiveness of this combination is determined by the following. Thermal insulation can prevent thawing of the soil of the base directly under the building. However, the thermal effect of the areas adjacent to the building can lead to thawing of pounds under the building next to the unfavorable zone, which will lead to uneven deformations. In this case, a vertical curtain of thermal supports protects against lateral thermal influence and reinforces permafrost directly under the building. The use of only thermal supports without thermal insulation leads to a sharp decrease in the permissible width of the building, which is determined by the distance between the thermal supports, at which their mutual influence takes place. In connection with the foregoing, it turns out that the total effect is higher than the sum of the effects of individual events.

APPENDIX

CONCLUSION OF THE FORMULA FOR THE CALCULATED DEPTH OF THE SMALL AREA UNDER THE BUILDING IN THE PRESENCE OF THE COOLING SYSTEM

To derive the formula for the estimated depth of the melt zone under the building, a series of three-dimensional thermophysical calculations was carried out according to the programs developed by the Central Scientific Research Institute of Computer Science. The initial data for calculating the building taking into account cooling systems (thermal support) were set taking into account the monograph (Passek V.V., Petrov V.I. Thermo supports - an effective and promising type of permafrost structures. - M.: TsNIIS, 2009. - 104 s).

The basic input data characterizing this particular object were adopted as follows.

The temperature inside the building was taken all year round plus 20 ° C, the outside temperature was for Salekhard. The diameter of the thermal support (hollow pipe) is 1.0 m, its depth is 20 m. The distance d between the opposite rows of thermal supports (from 10 to 30 m) and the thermal insulation value (from 0 to 50 cm of foam) varied.

, гдеThe obtained depth values of the melt zone in the center of the building, depending on the value

where

Δ _f - the actual thickness of the foam in a specific calculation option, m;

Δ - the maximum thickness of the foam (adopted 0.5 m).

The table shows the values of h _c for two values of "n" equal to 0 and 1.

Based on the data obtained, the formula is derived by selection:

, м;

, m;

where m = (0.8 ÷ 1.2).

Claims (2)

1. A permafrost building, containing a foundation located on the foundation soils, a body placed on the foundation, and a cooling system, and the foundation soils contain, at the end of the warm season, a thawed zone located above and a frozen zone below, while the building has a rectangular shape with a length of "l" and a width of "b", characterized in that it contains a thermal insulation layer equivalent to a foam glass with a thickness of "Δ", located between the building’s building and its foundation, and the soil cooling system is made in in the form of hollow pipes with an inner diameter of "D", plugged at both ends by covers and partially immersed in the soil in a vertical position, the pipes being located on the outside of the building along its side with a length "l" with a distance "c" between each other and at a distance " a "from the wall of the building, as well as along one pipe at the ends of the building in their middle, while the depth of the melt zone from the level of the natural surface of the soil in the zone of hollow pipes is" h _B ", and in the center of the building is" h _C ", while

where d is the distance between opposite rows of hollow pipes, m; D _C - conditional estimated internal diameter of the hollow pipe, m (assumed equal to 1.0 m); m - correction factor, taken equal to (0.8 ÷ 1.2), b / p; h, H - respectively, the height of the aboveground and underground parts of the hollow pipes, m 2. The building according to claim 1, characterized in that the hollow pipes contain a coaxially located pipe with a diameter of d _K inside the cavity, having side cutouts of area S in the upper and lower ends,

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