Groundwater

Gravity waters in the first surface level of the earth, located in a permanently existing aquifer, are groundwater. They differ in that they have a free surface, there is no solid roof over it from waterproof rocks. They are located in weakly cemented and friable rocks. Can fill cracks in sedimentary cemented, metamorphic or magmatic rocks, and also lie in quaternary sediments. Groundwater according to its occurrence is classified into several types: stratified, fractured and pore. Their formation is due to the infiltration of surface waters and atmospheric precipitation. The area of their finding most often coincides with the distribution of the aquifer, the thickness of which is not constant, but depends on the intensity of feeding, the distance to the unloading area of water-bearing rocks, and so on.

Groundwater has a main characteristic, distinguishing them from artesian, deeper waters - lack of pressure. They are influenced by meteorological conditions: temperature, atmospheric precipitation and pressure, evaporation, etc. Also important is the economic activity of man: the pumping of oil and water from the bowels, the construction of hydromeliorative and hydraulic structures, the fertilization of agricultural land, the extraction of minerals, etc. In addition, the hydraulic conditions are important: a change in the regime of draining, feeding and surface water bodies.

In construction, groundwaters cause damage, destructively affect concrete and other building materials. Before the design of the facilities, it is necessary to conduct a study of the territory, with special attention to the availability, nature, chemical composition (aggressiveness) of groundwater, as well as the expected water inflows. Aggressiveness is determined by the solubility of calcium carbonate and is estimated by the following degrees: total acid, leach, magnesian, sulfate and carbon dioxide.

For the national economy, these waters are of great importance, being the source of water supply for settlements, industrial facilities, etc. They are extracted by drilling wells and wells with gravel backfilling, combining with mesh braids. What are they dangerous? The presence of groundwater limits the implementation of individual construction processes, for example: the choice of the foundation, the presence of a basement, basement, cellar or septic tank.

Groundwater in the basement inhibits the process of excavation, as they dilute the soil and do not allow for construction. The walls lose their bearing capacity due to the fact that hydrostatic pressure affects the caissons of cellars and cellars, and leakage is lost. Groundwater in the basement significantly affects the strength of the foundation, and in addition, additional protective measures are required: insulation from capillary dampness at the floor level, protection of the walls by double coating with resin on plaster, hot bitumen or mixed cement mortar with addition of hydrozite. From the pressurized water, the protection of buildings is carried out by the device of drains and a water intake, and also by creating a waterproof wall shell and the basement floor.

The determination of the water table begins with the finding of an aquifer. On an even surface or area, it is everywhere the same, and with irregularities, the level passes higher in elevated places and lower in lowlands. Usually they are located at a distance of up to 20 m, in wetlands - up to 1 m. If water in the area is flooded with small depressions, then its level is above the surface of the earth. In rainy weather their level rises, and with a drought - goes down.

The determination of the groundwater table is of exceptional importance for the construction and laying of the foundation. From this will depend on the bearing capacity of the soil. If the level is too high, it is strictly forbidden to fill the foundation.