Depth of laying the foundation

Depth of laying the foundation depends on the type of soil, cudgels its freezing, the groundwater level. All these parameters can be checked if the dig pit-hole size of 0,8 x0, 8, and the depth of 2,0-2,5 m. Typically, the top layer is the topsoil. Its thickness varies in different areas - from 0,1 to 1,0 m and more. Topsoil is easy to learn because it is darker than the subsoil. There are many residues that are rotting. This soil must be removed under the whole house, because it unevenly compacted, which can lead to deformation of the building. Lies below the natural ground vegetation, which can build a foundation. Primers located at the base, must meet the following requirements: - have sufficient bearing capacity, as well as small and uniform compressibility - not distend - not slump or to sink - to be secure against accidental subsidence and landslides. Subsidence can occur when there is insufficient capacity reservoir of soil taken from the base, if underneath it is soft ground. Landslides may occur when the inclined strata that are bounded steep slope. The upper array of soil can slide under the weight of the erected structures, especially in proximity of groundwater. Most good reason is a homogeneous soil, it is uniformly upsets and construction costs it is more stable. Should be very cautious approach to the construction of buildings on the silty sands, saturated with water (quicksand), silt and loess soils. Nor can it be used as a natural base bulk and topsoil and peat. If the existing soil can not sustain a building erected on them, resorted to the device of artificial reason. The simplest artificial bases are sand and gravel. They are usually used when the geological conditions required by the device of deep foundations. In these cases, replaces the base of the rubble foundation. Sometimes the sand and gravel foundations used to increase the area of ??pressure transmission to the ground from the base of the foundation. Sandy foundation operates as a pillow, pour out of coarse sand. Should put the sand into layers of 15 cm, pour water, and pack carefully. The ground under the building or structure can be strengthened by the addition of gravel. His poured in the trench bottom layer of 15-20 cm, rams as long as the gaps do not seem to ground and then spiked again and continue until the beetle until it stops sediment detritus. To determine the depth of the foundation is paramount position of the groundwater level. At the position of ground water level at 1,5-2,0 m depth below the foundation base of his burial can not exceed 50 cm, as in most compressible zone base is normal humidity. When placing the groundwater level at a depth of less than 1,5 m from the surface of the bearing capacity of soil is reduced considerably, especially if groundwater is close fit (from 0 to 30 cm) to the foundation. In waterlogged and saturated soil water quantity foundation settlement is much greater than in moderately moist. In such soils the foundation was adjusted to the depth of freezing. Everyone is aware of a truism: the stronger the base, the durable construction. Distinguish the following main grounds on which it is recommended to lay the foundation: Rocky. Reliable, durable, not compressed, not blurred and not freeze. Foundations in such soils of the South lay directly on the surface. Gristly (cartilage, gravel, broken stone). Reliable, durable, not compressed and not blurred. Foundations in such soils should lay at a depth of not less than 50 cm, regardless of the depth of soil freezing. Sandy. Easily removed, well miss the water, much compacted under load and slightly frozen. Foundations in such soils may be pledged at a depth of 40 to 70 cm clay. Able to contract, to blur and freezing - slough. If such soils are found in wet environments, must lay the foundations of the calculated depth of freezing. Loam and sandy loam. Mixture of sand and clay particles. Loam containing from 10 to 30, fine sandy loam - 3 to 10% clay particles. Both of these soil occupy the gap between the spectral position of clay and sand. There is also loess which belongs to the group of clays, has a large number of pores and shrink when wet. If these soils are wet, the depth of laying the foundations should not be less than the calculated depth of freezing. Small and silty sands and cohesive soils is determined by appearance and feel (on a slightly damp raskatyvaemosti or taken from the depth of the sample): a) if the ground is impossible to unroll the cord, then the soil is sandy, and fine and silty, sands easily blown away with his hands; b) if the ground is impossible to roll out the cord with a diameter less than 3 mm, the sandy loam, and c) if the cord diameter from 1 to 3 mm, clay loam, and d) if it is possible to unroll the cord is less than 1 mm, the clay. Gravelistye, large and medium-sized sand will serve as a secure base homes. In such soils can lay the foundation to a minimum depth - 0,5 m. When used as a base of fine and silty sands should consider the level of groundwater. We can not allow saturation of fine sand with water, so as. from this reduced their load carrying capacity. The same drawback and have clay soils, which include clay, loam and sandy loam. There are also loess-like loams. At low humidity, they are able to withstand heavy loads, and the saturation of water can warp even under the influence of its own weight - to sink. Their legkolichit. Lump loess loam, pubescent in />, in contrast to conventional clay decays rapidly. Small and silty sand and clay soils, in addition, during the freezing can distend, resulting in an uneven foundation settlement and deformation of walls Therefore, in determining the depth of the foundation is important to consider the level of winter soil freezing. Observations of the depth of soil freezing are station meteorological service. The maximum depth of frost penetration is observed in the open, lofty, scavenged the ground, where poorly maintained snow. In determining the depth of freezing can be guided by the following data for areas around major cities: 1 m - Astrakhan, Kiev, Minsk, Rostov-on-Don, 1,2 m - the Great Luke, Volgograd, Kursk, Pskov, Smolensk, Kharkov, 1.4 m - Voronezh, Tver, St. Petersburg, Moscow, Novgorod, 1.5 m - Vologda, Nizhny Novgorod, Kostroma, Penza, Saratov, Cheboksary, 1,7 m - Izhevsk, Kazan, Samara, Vyatka, Ulyanovsk, Ufa. More precise information on the magnitude of the depth of frost penetration in your country, please contact your local project or a construction organization. Knowing the groundwater level and depth of soil freezing, can be identified and the depth of the foundations. So, if the groundwater level in the soil freezing period is lower than the calculated depth of freezing of more than 2 m, then for small and silty sands and clay soils of hard consistency depth of the foundations of the earth's surface can be taken regardless of the depth of freezing. Under such conditions the soil will not be puchitsya during freezing, because freezing layer is no excess water, and it is not moistened by capillary rise of water. At the level of groundwater below the calculated depth of freezing up to 2 m depth of laying the foundations for the small and dusty, sandy and clay soils of the plastic and fluid consistency shall not less than the calculated depth of freezing. The minimum embedment is the sole foundation from the ground level at the base, folded small dry coarse sand and clay soils of hard consistency should be 0.7 m, and saturated with water and fine silty sand, clayey soils with plastic consistency and subsidence loess-like loam - 1,0 m. The minimum penetration of the sole foundation basement walls of his or her sex is accepted 0,5 m