The main objective of this paper is to discuss the experimental and theoretical approaches developed by different researchers in order to understand and to evaluate the soil geosynthetic interaction under different loading conditions. In the paper, the soil-geosynthetic interaction in pullout, direct shear, and inclined plane tests under both static and cyclic loading is analyzed based on the different theoretical and experimental results carried out by the authors and also available in literature. For each type of test, the factors affecting test results and soil-geosynthetic interface behavior, the theoretical model developed to predict the interface resistance and mobilized friction, and the relevance of the interface parameters obtained through the different tests in the design and performance of geosynthetic reinforced earth structures are discussed in detail.

In this paper, a numerical model to simulate the hydraulic conductivity reduction observed during long-term laboratory column tests is proposed. The column tests are carried out to study dissolved heavy metals removal by using granular zero valent iron (ZVI). The proposed model is also used to analyse the main causes of hydraulic conductivity reduction observed during laboratory column tests. Expansive iron corrosion, precipitation of reaction products, and gas formation are the processes considered in the proposed model. Numerical simulation results show that to reproduce hydraulic behaviour of the experimental systems, the change of pores geometry due to expansive iron corrosion and precipitation of reaction products, which determines a possible stoppage of gas bubbles, should be considered. Furthermore, model results show that only a small percentage of the iron available is corroded during the tests (from 0.4% to 1.9%). According to the model, the average diameter of gas bubbles that better fit the experimental results varies between 0.16 and 0.19 mm. While assuming gas absence (or its possible escape), higher values of iron corrosion rate should be considered to fit the experimental results.