What do we want to learn today? How much does 1 cube of rock weigh, the weight of 1 m3 of rock? No problem, you can find out the number of kilograms or the number of tons at once, the mass (weight of one cubic meter, weight of one cube, weight of one cubic meter, weight of 1 m3) is indicated in Table 1. If anyone is interested, you can skim the small text below and read some explanations. How is the amount of substance, material, liquid or gas we need measured? Except for those cases when it is possible to reduce the calculation of the required quantity to the counting of goods, products, elements in pieces (piece counting), it is easiest for us to determine the required quantity based on volume and weight (mass). In everyday life, the most common unit of volume measurement for us is 1 liter. However, the number of liters suitable for household calculations is not always an applicable method for determining the volume for economic activity. In addition, liters in our country have not become a generally accepted “production” and trade unit for measuring volume. One cubic meter, or in its abbreviated version - one cube, turned out to be a fairly convenient and popular unit of volume for practical use. We are accustomed to measuring almost all substances, liquids, materials and even gases in cubic meters. It's really convenient. After all, their costs, prices, rates, consumption rates, tariffs, supply contracts are almost always tied to cubic meters (cubes), and much less often to liters. No less important for practical activities It turns out that we know not only the volume, but also the weight (mass) of the substance occupying this volume: in this case we're talking about about how much 1 cube weighs (1 cubic meter, 1 cubic meter, 1 m3). Knowing mass and volume gives us a fairly complete idea of quantity. Site visitors, when asking how much 1 cube weighs, often indicate specific units of mass in which they would like to know the answer to the question. As we noticed, most often they want to know the weight of 1 cube (1 cubic meter, 1 cubic meter, 1 m3) in kilograms (kg) or tons (t). Essentially, you need kg/m3 or t/m3. These are closely related units that define quantity. In principle, a fairly simple independent conversion of weight (mass) from tons to kilograms and vice versa is possible: from kilograms to tons. However, as practice has shown, for most site visitors a more convenient option would be to immediately find out how many kilograms 1 cubic meter (1 m3) of rock soil weighs or how many tons 1 cubic meter (1 m3) of rock soil weighs, without converting kilograms into tons or vice versa - quantities tons to kilograms per cubic meter (one cubic meter, one cubic meter, one m3). Therefore, in Table 1 we indicated how much 1 cubic meter (1 cubic meter, 1 cubic meter) weighs in kilograms (kg) and tons (t). Choose the table column that you need yourself. By the way, when we ask how much 1 cubic meter (1 m3) weighs, we mean the number of kilograms or the number of tons. However, from a physical point of view, we are interested in density or specific gravity. The mass of a unit volume or the amount of substance contained in a unit volume is bulk density or specific gravity. In this case, the bulk density and specific gravity of rocky soil. Density and specific gravity in physics are usually measured not in kg/m3 or tons/m3, but in grams per cubic centimeter: g/cm3. Therefore, in Table 1, specific gravity and density (synonyms) are indicated in grams per cubic centimeter (g/cm3)
Considering that the soil is a complex dispersed medium consisting of mineral solid particles and pore space filled in the very in general terms water (pore fluid) and air, the concept of density as a physical quantity is also complex and acquires certainty only if it is indicated exactly what the density of which soil phases is in question.
Next, the experiment is carried out in the usual manner described earlier. To determine the volume of clean soil, it is necessary to subtract the volume occupied by paraffin from the found total volume of waxed soil. The volume of paraffin is easily determined by weighing the sample before and after waxing and taking into account the specific gravity of the paraffin itself, usually close to 9 kN/m 3.
Specific gravity Monoliths of cohesive soils of significant size are determined with sufficient accuracy by directly measuring the monolith, which has been given the correct geometric shape, for example, cylindrical, and its subsequent weighing. In practice, to determine the specific gravity of wet (and dry) soil, a metal ring with a pointed cutting edge with a diameter of up to 15 cm and a height of up to 5... 10 cm is often used. To take a sample, the ring is pressed into the soil. The sample volume in this case is determined by the internal volume of the cylinder.
The specific gravity of wet clay soils is usually 19.5...21.0 kN/m3. The specific gravity of dry, non-cohesive granular soils usually ranges from 15.8 to 16.5 kN/m3.
The volume of non-cohesive sandy soils is determined in two states: the most loose and the most dense. The determination is carried out by placing sand in a measuring container, and the sands are tested dry or under water. The required maximum looseness of sand is achieved by carefully pouring it into a container, and the maximum density is achieved by carefully baying it until the mass is constant or by placing the container with sand on a vibrating table.
For high-quality engineering and construction calculations, various standards and indicators have been developed for the materials used. One of them - volume weight soil. This is one of the most significant physical parameters that is used for various types calculations.
Effect of volume on other quantities
This parameter is decisive for various qualities and properties of rocks and characterizes its features associated with structure and texture. The volumetric mass indicator is introduced as a calculation when calculating the pressure on a retaining wall, to determine the stability of landslide slopes, slopes, etc.The volumetric weight of the soil is used to calculate the same indicator of its skeleton.
Peculiarity
The value depends on a number of characteristics, namely humidity, porosity, the severity of its constituent minerals and the amount of organic matter.
In sedimentary rocks, it depends more on porosity than on the mineral composition, since it fluctuates significantly. In others, for example, igneous ones, on the contrary, the value of the mineralogical composition fluctuates. And it is of decisive importance for calculating volumetric mass.
Examples
Clayey, sandy and other dispersed soils have a volumetric weight of 1.3 to 2.4 g/cm³. For soils with rigid crystalline bonds between particles, such as igneous or igneous -2.5 - 3.5 g/cm³. Limestones have from 2.4 to 2.6 g/cm³, and sandstones range from 2.1 to 2.6 g/cm³.
Calculation methods
There are two known methods of determination: direct is a method with direct measurement of weight and volume, and indirect, accordingly, without this.
Watch the video: Design resistance of foundation soils. Estimation of settlement of columnar foundations.
Considering that soil is a complex dispersed medium consisting of mineral solid particles and pore space filled in the most general terms with water (pore fluid) and air, the concept of density as a physical quantity is also complex and only becomes definite in the event that it is indicated exactly what the density of which soil phases is in question.
Soil particle densityρ s is the ratio of the mass of the solid part of dry soil m s (excluding the mass of water in its pores) to its volume V:
Typically, the following units are used as a unit of measurement for the density of soil particles: kg/m3, g/cm3, t/m3, etc.
The density of soil particles depends on their mineral composition and the presence of organic and organomineral substances; therefore, it represents the weighted average density of these parts of the soil.
Particle Density individual species dispersed soils has the following values: sands - 2.65...2.67 t/m 3 ; sandy loam - 2.68... 2.72 t/m3; loams - 2.69...2.73 t/m3; clay 2.71 ...2.76 t/m 3 ; peat 1.50... 1.80 t/m3.
Density of wet soilρ w is the ratio of the mass of wet soil m w to its volume V w:
The density of dry soil ρ d is the ratio of the mass of dry soil m d (excluding the mass of water in its pores) to the volume occupied by this soil, which includes the volume of pores present in this soil:
These parameters are used to characterize physical properties soils and in dynamic calculations of structure foundations.
For engineering geotechnical calculations, related, in particular, to the determination of natural pressure and backfill pressure on retaining walls, not the characteristic of soil density is used, but the characteristic of its specific gravity, which is the ratio of the weight of the soil to the volume it occupies and measured in N/m 3, kN/m 3, mN/m 3 (SI system).
Specific gravity of soil particles γ s is the ratio of the weight of dry soil to the volume of its solid part.
Specific gravity of wet soil γ w is the ratio of the weight of wet soil to the entire volume occupied by this soil.
Specific gravity of dry soil γ d is the ratio of the weight of dry soil (skeleton) to the volume occupied by this soil, including pores.
Density and specific gravity are related to each other by a simple relationship. So, with a soil particle density p s = 2.71 t/m3, the specific gravity of particles of the same soil γ s = 10 р s = 27.1 kN/m3.
Determining specific gravity consists of two basic operations: determining the volume of a certain amount of soil and determining the weight of this volume of soil.
Determining the volume of a sample (monolith) of non-porous rock is carried out by immersing the sample in water and determining the volume of water displaced.
Determining the volume of a clay soil sample by directly immersing it in water is impossible; there is a real danger that the clay sample will either disintegrate or swell by absorbing water. For this reason, a sample of clay soil is pre-waxed before immersion in water, ᴛ.ᴇ. cover it with a layer of waterproof paraffin. When waxing, avoid possible entrapment of air (bubbles) between the soil and the wax. Next, the experiment is carried out in the usual manner described earlier. To determine the volume of clean soil, it is extremely important to subtract the volume occupied by paraffin from the found total volume of waxed soil. The volume of paraffin is easily determined by weighing the sample before and after waxing and taking into account the specific gravity of the paraffin itself, usually close to 9 kN/m 3.
The specific gravity of cohesive soil monoliths of significant size is determined with sufficient accuracy by directly measuring the monolith, which has been given the correct geometric shape, for example, cylindrical, and its subsequent weighing. In practice, to determine the specific gravity of wet (and dry) soil, a metal ring with a pointed cutting edge with a diameter of up to 15 cm and a height of up to 5... 10 cm is often used. To take a sample, the ring is pressed into the soil. The volume of the sample in this case is determined by the internal volume of the cylinder.
The specific gravity of wet clay soils is usually 19.5...21.0 kN/m3. The specific gravity of dry, non-cohesive granular soils usually ranges from 15.8 to 16.5 kN/m3.
The volume of non-cohesive sandy soils is determined in two states: the most loose and the most dense. The determination is carried out by placing sand in a measuring container, and the sand is tested dry or under water. The required maximum looseness of sand is achieved by carefully pouring it into a container, and the maximum density is achieved by carefully baying it until the mass is constant or by placing the container with sand on a vibrating table.
Knowing the properties of the soil is necessary when carrying out any work: from digging a garden to complex construction processes. The specific gravity of soil is one of the first indicators that we come across. It must be distinguished from density. When calculating it, divide the weight of a substance by its volume, and the formula for density is: mass divided by volume. Different systems use different units of measurement, the non-systemic unit is G/cm³.
Dependence on composition
For minerals it is usually in the range from 2.5 to 2.8 G/cm³. As heavy minerals increase, the weight of the soil also increases. With organic substances, on the contrary: the more there are, the smaller it is.
The influence and role of water
Before carrying out calculations, it is necessary to establish the volume and weigh it. This is determined by immersion in water.
The presence of water in the composition, that is, humidity, has a significant influence on the calculation. Based on this indicator, two groups are distinguished: wet clayey and dry loose granular. In group 1, the soil weight in kN/m³ ranges from 19.5 to 21.0. Group 2 has from 15.8 to 16.5 kN/m³.
Watch the video: TYPES OF SOIL. SOIL ANALYSIS.
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