Depth of soil

Greater depth of soil when there is a deep layer of soil, the intensity of the earthquake will reduce. The greater the distance from the focal point, the smaller will be ground movements. In such cases it is seen that the settlement of the soil below the structure may be negligible as it would have already settled by the time the shock reached the surface, and hence damage to the structure would be reduced. 

Soil does not provide as solid a base as rock. The strength of a foundation built on soil and its ability to withstand an earthquake will therefore depend upon the quality and depth of soils which may be formed of a number of soil layers of different stratifications and depths. Sandy soil or soil with sedimentary deposits, for instance, will have less strength and will provide a weaker base, as such soils may settle more during a ground movement. 

Many thousands of miles of steel pipeline have been laid under, or in contact with, the ground for the long-distance transport of oil, natural gas, etc. Obviously corrosion is a problem if the ground is at all damp, as it usually will be, and if the depth of soil is not so great that oxygen is effectively excluded. Then the oxygen reduction reaction... 

For example, the expected zero-time soil concentration (Co) of a compound applied at a rate of 2.2kga.i.ha would be calculated by dividing the application rate (mga.i.ha ) by the total weight of a 15-cm depth of soil. Assuming a soil bulk density of 1500 kg m , the total weight of a 15-cm layer of soil is 2.24 x 10 kgha ... 

For these reasons, it is desirable to perform a series of simple calculations to determine if the field capacity for a given depth of soil is ever exceeded, rather than simply overlaying water inputs over plots of residue data. The following series of calculations addresses the primary issue of whether sufficient water was applied to the test system at appropriate intervals to create leaching opportunities ... 

Since the soil normally means poorer heat conduction than the rock an unexpected large depth of soil results in a too short borehole. This will lead to under dimensioning and a risk of freezing in the casing. 

Remediation with plants requires that the contaminants be in contact with the root zone of the plants. Therefore, root morphology and depth directly affect the depth of soil that can be remediated or the depth of groundwater that can be influenced. A fibrous root system such as that found in grasses has numerous fine roots spread throughout the soil and provides maximum contact with the soil because of the high surface area of the roots. A tap root system (such as in alfalfa) is dominated... 

SOL Z (mm) Depth from soil surface to the bottom of a layer. Since all the subcatchments were conceptualized as single layer units, SOL Z is equal to SOLZMX (mm), the maximum rooting depth of soil profile. 

Fig. 16.1 Plot of percentage of applied dose of pesticide remaining in soil versus depth of soil at various time intervals after application, (a) 31 days, (b) 66 days, (c) 93 days after pesticide application Source Own files...

At the end of 24 h, measure the depth of the settled soil. This represents the total depth of soil. 

Experimental data can be used to compute the diffusion coefficient based on Fig. 7 as a function of PV for a particular depth of soil, or as a function of depth. One should recognize the importance of the determination of D values in relation to elapsed time and distance from pollutant source. In many instances, the prediction of the advance of a pollutant plume and rate can be very sensitive to the specification of the D coefficient. 

Another method of charring is in use, especially at Wicnerwald, and also in mountainous districts where there is no great depth of soil, and where resinous wood is operated upon. The form of the heap or pile is shown in Fig. 22—a kind of structure termed SaufenvsrJsoUnng, and offering facilities of charring endeft wood of every dimensions. When this mode... 

In addition to expressing soil C stocks on an areal basis, it may be preferable, particularly for comparisons of C stocks due to land use changes that alter bulk density, to express soil C stocks on an equivalent mass basis. This approach, nicely explained by Ellert et al. (2001), samples to a depth giving a constant mass of soil at all locations or time points, rather than a constant depth of soil. Calculating the required depth requires bulk density measurements. 

L is termed the diffusion length, and is a measure of the depth of soil from which diffusion of radon is effective. The flux of radon at the surface is... 

Figure 4 shows pesticide volatilization as affected by soil depths of 1, 5, and 10 cm with water evaporation (E) equal to 0.25 cm/d. Since the concentration is inversely proporational to the depth of soil containing the 1 kg/ha of pesticide, the ratio of the concentrations roughly explains the initial relative volatilization rates. The very water soluble (Category III) compounds appear to approach a constant volatilization rate regardless of depth because their volatilization is controlled by diffusion of the chemical through the boundary layer above the soil surface as well as by the rate of movement upward to the soil surface. 

Biodegradation rate constants k = 0.047 d 1 from soil incubation studies and k = 0.026 d 1 in anaerobic system from flooded soil incubation studies both by die-away test (Rao Davidson 1980 quoted, Scow 1982) t,/2 = 40 d in 0 to 10 cm depth of soil (Rao Davidson 1980 quoted, Jury et al. 1983, 1984, 1987a, b Jury Ghodrati 1989)... 

Radionuclides applied artificially or as a result of contamination in the field Depth of soil contamination Container type Soil pH... 

Soil Initial moisture content (percent) Depth of soil column (in.) Duration of experiment (days) Initial porosity Rate of moisture loss (in. per yr)... 

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