An experimental study about the effects of the partially drained strain paths on the monotonic behavior of loose silty sands using triaxial tests

The mechanical behavior of silty sands is one of the crucial topics in the field of soil mechanics. However, many studies have been conducted to determine the main features of the silty sand mixtures; there are some non-clarified mechanisms yet. Most of the previously applied studies have been focused on the behavior of silty sands under conventional paths such as consolidated drained and consolidated undrained stress-strain paths. Recently done investigations have shown the assumption that the mentioned conventional paths are not the critical ones for all situations. Therefore, considering partially drained paths not only can help to understand the mechanical behavior of silty sands better but also is necessary to ensure the safety of the projects. In this paper, 14 triaxial shear tests are applied to assess the effects of the partially drained paths on the main features of the shearing mechanism of silty sands. As the water inlet is the most critical path between the partially drained tests, this research is done by considering only this type of partial drainage and ignoring other non-crucial partially drained strain paths. Achieved results indicate that partial drainage can affect the behavior of samples with a little fine content (up to 5%) significantly, while for samples with more fine content, these effects are not considerable. In other words, samples, which not exhibit a fully static liquefaction (completely softening behavior), will be considerably affected by partial drainage. Effects of water inlet during shearing on the asymptotic stress ratios, excess pore water generation, and experienced stress paths are investigated, as well.