دانلود رایگان مقاله انگلیسی نفوذ پذیری آب خاک های غیر اشباع در منطقه بایر - اشپرینگر 2017

Abstract

The moisture permeability of sandy soils in the unsaturated moisture content regime has been studied. The intensity of moisture conductivity was measured at certain values of the current moisture. It is shown that the expansion of the range of unsaturated soil moisture makes it possible to determine the point of break in the monotony of the curve of simulation of moisture permeability due to the rupture of the capillary connection. The mathematical model of moisture permeability that takes into account the soil porosity is presented.

RESULTS AND DISCUSSION

The use of the numerical array that was obtained as a result of observations and combined into the database is hampered by the fact that the tabular data reflecting the hydrophysical processes require significant costs for the statistical processing, interpolation, extrapolation, regression analysis, etc. To perform the mathematical simulation and prediction of the situation in a specific region, it is more convenient to present the data from the lysimeters in the form of continuous functional relationships. These relationships, e.g., the relationships between moisture permeability, Kw, and moisture in the unsaturated soil can be revealed using a formal physicomathematical model or on an empirical basis, i.e., by matching the parameters of an appropriate continuous function using the regression analysis. The detailed semiempirical approach assumes the simplification of the results of formal simulation for practical application [1]. The objective of this work was to study the issues of hydrophysical support in the form of lysimetric data for simulating the dynamics of moisture transfer.

Lysimetric observations made it possible to assess the rate of the flow under different moisture conditions within the minimum moisture capacity (MMC), i.e., the WP. The closest relationships between the flow rate and moisture were recorded in those cases when the indices of moisture of the above-capillary film edge are used [6]. The functional relationship between these parameters can be described as the following relation: K(w) = 0.0002e0.8w at R2 = 0.89, where K(w) is the rate of the gravity flow, mm/h, and w is the gravimetric moisture, % [5].