Practica masa volumen del suelo

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  • Publicado : 16 de noviembre de 2011
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Objetivo
Evaluar las características físicas del suelo y definir sus componentes principales con base a su masa y volumen, expresándolos en ecuaciones matemáticas, para aplicar los algoritmos para la obtención de componentes por medios indirectos, en dos muestras diferentes.
Introducción
La evaluación de las características del suelo y la identificación se sus propiedades especificas quepuedan servir como indicadores de su función presentan grandes variantes debido a muchos aspectos que definen a dicho sustrato y a los múltiples factores, físicos, químicos y biológicos que controlan los procesos biogeoquimicos y su variación en el tiempo, espacio e intensidad.
El estudio de las características en relación a la masa volumen, se realizan con el fin de conocer dicho estrato de formaestructural y así determinar sus bondades o limitaciones, y así discernir y tomar decisiones para realizar acciones mecánicas pertinentes, con respecto a la actividad en cuestión ya sea agronómica, ambiental o en el ramo de la construcción.
Marco Teórico
Volume And Mass Relationship Of Soil Constituens

We now consider the volume and mass relationships among the three soil phases and definesome basic parameters that have been found useful in char- acterizing the composite soil physically. Figure 1 is a schematic representa- tion of a hypothetical soil in which the three phases have been separated and stacked one atop the other for the purpose of showing their relative volumes and masses. (To do so in practice, we would need to compress the solid parti- cles into a single porelessblock, an obvious impossibility. But in the process of pedagogy, assuming the impossible is commonplace.)

In Fig. 1, the masses of the phases are indicated on the right-hand side: the mass of air Ma, which is negligible compared to the masses of solids and water; the mass of water Mw; the mass of solids M4 and the total mass M t. (These masses can also be represented in terms of their weights,being the product of each mass and the gravitational acceleration.) The volumes of the same components are indicated on the left-hand side of the diagram: volume of air V~, volume of water Vw, volume of pores Vf = V~ + Vw, volume of solids Vs, and the total volume of the representative sample Vt.

On the basis of this diagram, we can now define terms that are generally used to express thequantitative interrelations of the three primary soil phases.

Density Of Soil (Mean Particicle Density) Ps

Ps=Ms/Vs

In most mineral soils, the mean mass per unit volume of solids is about 2600-2700 kg/m 3. This is close to the density of quartz, which is generally the most prevalent mineral in the coarsest fraction of the soil. Some of the miner- als composing the finest fraction of the soilhave a similar density. However, the presence of iron oxides and of various other "heavy" minerals (generally defined as those having a density exceeding 2900 kg/m 3) increases the average value of ps, whereas the presence of low-density organic matter generally low- ers the mean density of the solids. Sometimes the density is expressed in terms of the Gg, which is the ratio of the density of anymaterial to that of water at 4 ~ C and at atmospheric pressure. The latter density is about 1000 kg/m 3, so the specific gravity of the solid phase in a typical mineral soil is about 2.65, a value that is numerically (though not dimensionally) equal to the density expressed in the cgs system of units (g/cm3).

Air
Mt
Solids
Ma=o
Water
Mw
Ms
Va
Vw
Vs
Vf
Vt
Volume Relations
MassRelations
Fig 1 Schematic diagram of the soils as a three-phase system

Dry Bulk Density (Pb)

Pb=MsVt=MsVs+Va+Vw

The dry bulk density expresses the ratio of the mass of solids to the total soil volume (solids and pores together). Obviously, PB is always smaller than p~. If the pores constitute half the volume, then PB is half of p~, namely about 1300 to 1350 kg/m 3, equivalent to a bulk...
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