The results of previous studies on reconstituted specimens showed the significant influence of initial moisture, the state of stress, and the loading path on the hydro-mechanical behavior of Golestan’s loessial soil during the application of loading (Haeri et al. 2012). Haeri et al. (2012) reported significant changes in both volume and water content during wetting. The rates of change of both water content and deformation, however, were different


More than 17% of Golestan province in the northeast of Iran is covered by thick layers (up to 200 m) of loessial soil (Feiznia et al. 2005) with a relatively low natural in-situ water content. When a sudden precipitation event occurs, excessive settlements are typically reported in this area, which have historically been damaging to a variety of civil engineering structures (e.g., Haeri et al. 2012). This settlement behavior is generally attributed to the specific formation and weak inter-particle bonding forces between the particles that occur in these type of soil deposits, which together yield a soil void structure that is susceptible to collapse (e.g., Klukanova and Sajgalik 1994). Due to the rapid development that has occurred in this area, there is an increase in

depending on the state of stress that was applied to the specimens. At higher levels of suction, the soil specimens experienced a fairly small increase in void ratio with matric suction decrease. At lower levels of suction, more water was absorbed by the mineral structure during wetting; as a result, these specimens experienced appreciable collapse and dramatic changes in soil volume. Very similar results have been reported by Maâtouk et al. (1995), Cui & Delage (1996), Chen et al. (1999), Pereira & Fredlund (2000), Rampino et al. (2000), Futai & Almeida (2005), Jotisankasa (2005), and Zhou & Sheng (2009) for tests on similar types of collapsible soil.