An experimental investigation of the independent effect of suction and degree of saturation on very small-strain stiffness of unsaturated sandArianna Pagano, Alessandro Tarantino, Meghdad Bagheri, Mohammad Rezania and Philippe SentenacE3S Web Conf., 9 (2016) 14015DOI: https://doi.org/10.1051/e3sconf/20160914015