The main defects of foundations

The foundation stone (rubble, block, etc.) are possible: local subsidence, vertical and oblique fractures; leach salts from the grout, masonry separation and loss of individual stones (in the rubble foundations); dampness on the inner surfaces of the basement. Damage to or destruction of the foundations also contributed to leaching of soil bases, his bulging (clay, loam, etc.), water saturation of soil adjacent to structures, the appearance in the groundwater of substances corrosive to the material foundation. Subsidence of foundations, ie, a gradual lowering of the ground under the influence of upstream loads in low-rise housing construction is a relatively rare phenomenon. Typically, the support area of ??the foundation being built, especially tape, significantly higher than estimated and neprosadochnyh soils almost always ensures their stable state. Uneven foundation settlement most often observed in the initial period of operation of the house when there is sediment bottom. Later it may occur when you change the mode of functioning of soil base. Signs of uneven foundation settlement are: the appearance of the walls of vertical oblique fractures, curvature of horizontal lines (cap series masonry joints), the deviation of the building walls, etc. In order to avoid drawdown footprint calculation and check the foundation if necessary, increase: in tape foundations due to the broadening of the lower part of the columnar, in addition, by reducing the distances between the pillars. In areas with high groundwater located at the bases of low-rise buildings affected by the powerful forces of frost heave. In severe heaving soils (water-saturated clay, loam, sandy loam, silty and fine sands), these forces reach 100-150 kPa (10-15 ts/m2) and, acting on the foundation from the bottom up, often exceed the load placed designs. In this case, seasonal Palm displacement of the surface layer of soil when it promerrzanii 1-1,5 m are 10-15 cm skewed porch, patio, porch, and sometimes the walls of houses - in most cases the result of exactly the forces of frost heaving of soils. The mistake many individual developers is confident that the deeper laying the foundation for the better, and that such a solution in itself ensures its reliable performance and stability. Indeed, at the location of foundation base below the freezing ground vertical forces of frost heaving cease to operate on her bottom, but the tangential forces of frost heaving, acting on the lateral surface of the can and in this case, pull out the foundation, along with frozen ground or remove it from the top of the bottom. Such cases are most likely to occur when constructing the foundations of stone, bricks or small blocks, especially for light buildings and structures. To prevent deformation of the foundations on heaving soils, it is necessary not only to place them in the sole below the level of soil freezing and thereby get rid of the direct pressure of the frozen soil below, but you must also neutralize the tangential forces of frost heaving, acting on the lateral surface of the basement. For this purpose, can be applied the following activities during installation of foundations: the slanted walls, plastering walls, preventing them from freezing ground, vertical reinforcement, connecting the upper and lower parts of the foundation, anchor the device at the bottom of the foundation, insulation blind area to reduce the depth of soil freezing, drying soil drainage. To cover the lateral surfaces of the foundation to create a sliding layer use waste oil or plastic wrap. The surface layer of soil can warm a slag, limestone, agloporite, foam. This method allows to reduce the local depth of soil freezing can be applied to previously constructed shallow-buried foundations "need protection from frost heaving. The construction of buildings on steep-falling relief must take into account the lateral pressure of soil, its possible shift. The magnitude of this pressure depends on many factors (the steepness of the slope, hydro-geological composition of soil, etc.) and difficult to transfer. Typically, in these conditions more reliable tape foundations, rigidly connected to the trial and transverse directions. Pier foundation in this case it is necessary to combine hard-reinforced concrete on top of the belt (grillage) so that all design elements working together. Work on the installation of foundations should be started after the harvesting of basic building materials so as to build a house and putting it into operation carried out in one construction season. Foundations, erected in heaving soils and abandoned for the winter without load (without walls, floors and roofs) may be deformed. Unanticipated strain may occur in the case when the house was built in the winter time is not maintained and not heated, and the depth of laying its foundation has been calculated on the thermal heat homes. Damage to foundations and walls of the basement probably due to insufficient depth of the basement area and its poor quality of masonry, wetting or freezing in the construction process.