Effects of soil parameter variation and grid deformation on the numerical simulation of aquitard consolidation

  • Author(s): Tung-Lin Tsai, Chen-Chang Peng, and Xi-Jun Wang
  • DOI: 10.3319/TAO.2017.11.01.01
  • Keywords: Grid deformation, Soil parameter variation, Aquitard consolidation, Numerical simulation
  • Only incorporating soil parameter variation consolidation
  • Only considering grid deformation misestimates or underestimates consolidation
  • Both effects must be considered for numerically simulating consolidation
Abstract

Changes in soil parameters such as saturated unit weight (body force), hydraulic conductivity, and elastic modulus must be considered for simulating aquitard consolidation.In addition to changes in soil parameters, grid intervals change the subsequentsoil deformation in such simulations. This study incorporated and examined the effects of both the grid deformation and soil parameter variation on the numerical simulation of aquitard consolidation caused by hydraulic head decline in a multilayered aquifer system. According to the nondimensional analysis, the deformation number can be regarded as a dimensionless parameter for assessing whether thegrid deformation and soil parameter variation affect this simulation. The results revealed that when the deformation number exceeds 0.01 (i.e., when the aquitard is thick or soft), both the grid deformation and soil parameter variation must be simultaneously considered to increase accuracy. Aquitard consolidation was always overestimated when only thesoil parameter variation was considered. However, when only thegrid deformation was considered, theaquitard consolidation was eitheroverestimated or underestimated depending on whether the influence of the change in the body force was more substantial than that of the elastic modulus.

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