J.bazargan and H. Bayat,
Volume 21, Issue 1 (7-2002)
Abstract
As a result of the limitations in the application of Darcy Law (V=ki) to linear-laminar flow regimes through porous media and due to the fact that in coarse alluviums, the Reynolds number may exceed its critical value, the so-called Laplas equation cannot be used for precise analyses of coarse granular foundations. A more general relationship is, therefore, required for such cases. However, a common relationship between piezometric gradient "i" and the approach velocity "v" within porous media shown as i=mVn leads to major difficulties in undertaking complicated tests to determine the values of m and n. It is shown that by combining the above-mentioned relationship with the continuity equation, a differential equation may be obtained to give piezometric head and a potential function Φ, which in turn, leads to the uplift force distributions and the seepage quantities through porous media. To overcome difficulties associated with m and n estimations in the model and as a result of fulfilling an extensive research programme, a fresh and reliable procedure has been developed and explained to assess m and n by means of a simple stepped pump-out test. The practical applicability of the method for a given confined aquifer is also examined. Findings indicates that the proposed procedure a) makes the use of the differential equation for turbulent flow in porous media possible, and b) provides means to determine the nonlinear equation parameters (m&n) at an acceptable precision. The computed values of the parameters are also submitted.
Keywords: Turbulent flow, Rock fill, Alluvium foundation, Reynolds number, Aquifer
K. Badv,
Volume 24, Issue 1 (7-2005)
Abstract
Contaminant transport analysis was performed for four selected solid waste landfill designs using the computer code POLLUTE. The diffusion coefficients were determined for the natural soils (aquitard) and compacted soils from the Urumia landfill site, using the diffusion tests. These coefficients along with the geometrical, physical, and chemical parameters of the natural soil and engineered layers, as well as the dominant boundary conditions were used in the analysis of the four selected
designs for the landfill. These designs were evaluated for the contamination of the underlying aquifer in a specified period, using the drinking water standard for chloride ion. The comparisons showed that the fourth design which includes the engineered elements of a blanket type leachate collection layer and a compacted clayey liner underneath the landfill base, has more certainty in controlling the contaminant transport from the landfill base to the underlying aquifer. This type of landfill could be introduced as an optimum and semi-engineered design to be used for solid waste landfills in Iran.
