RU70670U1 - HEAT-INSULATED FOUNDATION - Google Patents

Abstract

The heat-insulated foundation is a plate of extruded polystyrene foam, which is finely buried under the structure being erected, according to the formula

δ≥λ (R-1.05),

where δ is the thickness of the extruded polystyrene foam, m;

λ is the coefficient of thermal conductivity of extruded polystyrene foam, W / (m · ° C);

R is the reduced heat transfer resistance, m ² · ° C / W.

This ensures the performance of the bearing, heat and waterproofing functions while simplifying the design. 1 n.p. crystals, 1 Fig., 1 tab.

Description

The utility model relates to the field of construction and can be used in the construction of a shallow foundation or the foundation of a building structure.

A heat-insulated foundation is known, containing foam-permeable breathable and heat-insulating layers, finely buried successively located from the ground, on which a concrete layer is located (FI 75384, E02D 27/01, Е04В 1/70, Е04В 1/92, 1988).

To increase the bearing capacity and manufacturability, the foundation is formed from foam or foam urethane boards, on top and between the ends of which concrete inserts are made with the formation of a monolithic screed in the form of an upper flooring (GB 2300009, Е01С 3/00, E02D 27/01, Е04В 1/00, 1996). The design can be further strengthened with a lower concrete screed, also made in the form of flooring (EP 1258566, E02D 27/01, 2002).

A thermally insulated foundation is also known, including a rigid body located on the freezing soil with protrusions and sashes from the side facing the soil and inserts in the foundation sills of a material having a deformation modulus different from the deformation module of the protrusion material, and the inserts in the stubs are made of heat-insulating material for example, polystyrene foam (RU 2135693, E02D 27/01, 27/35, 1999).

Closest to the claimed is a thermally insulated foundation containing a supporting and heat-insulating elements, while the supporting element is a reinforced concrete slab, the bottom of which is made scribbles, and heat-insulating elements are formed by polystyrene inserts located in the stubs, and a plate insulation protected by waterproofing membranes (WO 2005042854, E02D 27/01, 31/02, 31/10; EV 5/00, 2005).

However, the well-known thermally insulated foundations are complex in design, since they are made of multi-element configured nodes.

The objective of the proposed technical solution is to simplify the construction of the foundation.

The solution to this problem lies in the fact that it uses a plate of extruded polystyrene foam, finely made according to the formula, which is finely buried under the erected structure as a supporting, waterproofing and heat-insulating elements.

where δ is the thickness of the extruded polystyrene foam, m;

λ is the coefficient of thermal conductivity of extruded polystyrene foam, W / (m · ° C);

R is the reduced heat transfer resistance, m ² · ° C / W.

Formula (1) is applicable for buildings with a base load of up to 5 t / m ² , which are, in particular, structures with a shallow deep foundation, where, as established by the authors (this is also seen from the formula), the dependence of the base thickness on the load may not taken into account. The fact is that a much sharper dependence is manifested here between the heat-insulating and water-absorbing properties of the foundation, depending on its thickness. It is only important to exclude the accumulation of soil under the structure associated with freezing of the soil in the winter. In the proposed design, as established in practice, this is eliminated.

Marking

where δ _n is the nominal value of the thickness of the extruded polystyrene foam, the formula (1) is reduced to:

The resulting formula (3) is used below for the convenience of representing the thickness of the foundation in relative units.

For example, to build a foundation in the Leningrad Region for a structure made of foam 40 grade we have: λ = 0.032 W / (m · ° C); R = 3.2 m ² ° C / W. According to formula (1), δ≥0.032 (3.2-1.05), i.e. δ≥0.043 m. From the standard range of assortments, foamplex-40 with a thickness of 50 mm is selected.

The causal relationship of the changes made with the technical result achieved is that the simultaneous performance of the supporting, heat-insulating, waterproofing functions of a solid made of extruded polystyrene foam base is possible only when performing dimensional characteristics according to formula (1). Otherwise, the foundation may be deformed, which will lead to deterioration of heat and waterproofing properties or even to destruction of the building structure.

The proposed foundation may be in the form of a continuous plate or frame around the perimeter of the structure.

Figure 1 shows a drawing of the foundation; Table 1 presents the technical characteristics of the foundation for various values of δ.

The heat-insulated foundation (Fig. 1) is a plate 1, finely buried in the ground 2 under the structure being erected, a wall, an additional heat-insulating layer of the wall and the floor of which are designated 3, 4 and 5, respectively. Plate 1 is made of extruded polystyrene foam according to the formula (1). At the installation site of the foundation 1, a leveling bed 6 and an upper sealing blind area 7 of the building are made from below.

Table 1 shows the results of testing variants of a physical model of a thermally insulated foundation in the winter period at nominal, permissible and transcendental values of its thickness and heat input at the rate of 50 ÷ 100 W / m ³ . As can be seen from the table, at an outdoor temperature of -20 to -25 ° С and a nominal value of the foundation thickness, the room temperature is close to room temperature, amounting to 13 ÷ 22 ° С. At the same time, the water permeability of the foundation is provided in the norm (22 ÷ 30 G / m ² per day). FROM

a decrease in the thickness of the foundation to 0.5 δ _n significantly increases heat loss, as evidenced by a decrease in room temperature to 5 ÷ 14 ° C. A further decrease in the thickness of the foundation to 0.1 δ _n leads to deformation of the structure, up to its destruction. At the same time, water permeability increases to 55 ÷ 72 G / m ² per day, and when the minus temperature is reached, the structure freezes.

Using the proposed technical solution in comparison with its analogues allows you to:

- to simplify the design of the target structure due to its single-layer execution, since the material used, subject to the conditions according to formula (1), carries out the bearing, heat insulating and waterproofing functions;

- to ensure uniform load distribution over a large area of the base;

- erect structures on “weak” soils, since the destructive effect of heaving soils is excluded;

- provide drainage around the perimeter of the structure;

- ensure the technological effectiveness of the construction of the foundation, which results in the exclusion of damp processes, reducing the duration and cost of construction.

Claims (1)

A heat-insulating foundation containing a bearing, waterproofing and polystyrene heat-insulating elements, characterized in that as a bearing, waterproofing and heat-insulating elements it uses a finely extruded polystyrene foam plate under construction to be erected in a thickness according to the formula δ≥λ (R-1.05), where δ is the thickness of the extruded polystyrene foam, m; λ is the coefficient of thermal conductivity of extruded polystyrene foam, W / (m · ° C); R is the reduced heat transfer resistance, m ² · ° C / W.