Geology for a cottage in Moscow

Loess Study

Geology for a cottage in Moscow is engaged in the study of the properties of soils, flowing in their natural processes. The properties of loess rocks strongly depend on the water content in a coherent state. In this state, it may be due to clay particles. The amount of cohesive water depends on the number of plasticity, the yield strength. Usually these characteristics are compared with each other. In the loess rocks, the clay component is not so much, so the hydrophilicity index (humidity divided by yield strength) is greater than one. Activity is determined by the number of plasticity divided by the content of the clay component. For this indicator, loess-containing soils are inactive.

Geology under the cottage is a very important stage before construction. The density of a rock is the ratio of its mass to the volume of this rock. The pycnometer is used to determine it. The density of loess precipitation ranges from 2.54 to 2.72 grams per cubic centimeter. Low density in soil containing humus - 2.54-2.60 g / cc.In the low-lying parts of the plates, the plains have an average density of 2.67 g / cc. When the clay component prevails in the loess rocks, the cutting ring method is used to determine the density. To determine the density of sandy loess variety - the method of holes. When the soil is clay and sandy - a radioisotope surface-depth densitometer can be used. Due to the fact that the measurement error reaches 0.04 g / cubic centimeter, usually increase the number of measurements in order to achieve the required accuracy.

Low density of loess soils is associated with significant porosity and low humidity. In loess-like, loess-like soils, it is higher. There is a tendency to increase the density with increasing depth. Lower density values ​​for drier areas. The density of the skeleton of loess soils is 1.12 - 1.79 grams per cubic centimeter, often in the range of 1.4-1.6 g / cc. When the density of the skeleton is higher than 1.4 g / cc, the subsidence properties of soils decrease. But there is no direct dependence of subsidence on the skeleton density. This is due to the fact that the density expresses only the whole porosity without any qualitative regularities.The average porosity of loess soils is forty-five percent and can range from thirty-six to fifty-nine percent.

Geology for a cottage in Moscowexplores in detail the features of the loess soils that are widespread in the central areas. In loess the following types of pores appear:

  • macroporosity
  • intra-aggregate
  • interparticle
  • large voids.

Large voids, cracks can occur due to suffusion-karst processes. The interparticle pores make up about thirteen to thirty five percent of the total rock volume. Such pores have a size of 0.5-0.002mm, the shape of the pores is mostly irregular. According to this porosity, water can be filtered in the free and capillary state. Pores and macropores measure from fractions of a millimeter to three millimeters. They can be discerned with the naked eye. Macropores are represented mainly by vertical branching tubular channels. When a load is applied on soils, or when they are moistened, there is a reduction in voids, large, interparticle, and micropores. This is an active porosity, the diameter of the pores is more than two hundredths of a millimeter. To determine such porosity, there is the Galay BF capillary-metric method.This is a fairly accurate method. If you do not need too much accuracy - use the channel method of Larionov AK. The method is based on the penetration of a viscous liquid (glycerin with large molecular sizes) during infiltration at the beginning to the largest pores. A temperature range of eighteen to twenty degrees is maintained. A dry, air sample is taken. It breaks along the long side, diagonally, in diameter. Glycerin is applied to the fracture using a pipette. A stopwatch measure the time of absorption of glycerin. Measurements are made at five to six different points. Static processing of the results is carried out, the average value is calculated.

Microaggregates are composed of elementary particles, the pores between them form intraaggregate porosity. Water resistance, permeability, breathability, moisture content of the rock depend on such porosity. Loss porosity is greater than loess-like porosity. In loess-like soils, with increasing depth, the porosity also becomes less.

How to determine the subsidence of loess soils

To determine subsidence, the rock layers are studied,The thickness of loessial rocks with subsidence properties is determined. To make a prediction on the section buildings are applied with foundations, which are placed at different depths. Determine the amount of subsidence at the lowest depth of the foundation. The whole strata of rocks is divided into layers. Determine the pressure on each layer along with its own weight of each layer. Build a graph of pressure distribution. According to the sections obtained as a result of geological study, the tables, and the graphs obtained, the total subsidence of all layers is determined. Comparisons are made of different results. Preliminary work is carried out on the site where construction work will be carried out. A platform of a certain width is selected, approximately equal to the thickness of the layer of subsidence rocks. The embankment of this site is being carried out. An observational geodetic network (brand) is established. Soils are soaked, loess rocks begin to subside. Deformations are measured by geodetic instruments, based on a pre-set bench mark. Such an experienced learning process can last for several weeks.

Geology for a cottage in Moscowis especially necessary when dealing with complex soils. You can get completely different results, for example, on soils that have not yet been subject to subsidence and on sagging soils. If you do not deal with this - the subsidence may be incorrectly understated.

FirmLLC "Association of Prospectors"will perform all the necessary studies on loess soils.


Date: 10.10.2018, 15:19 / Views: 35133

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