Effect of soil structure disturbance on the shear strength of black volcanic ash soilOkri Asfino Putra, Noriyuki Yasufuku, Ryohei Ishikura, Ahmad Rifa’i, Adel Alowaisy and Yuko KawaguchiE3S Web Conf., 156 (2020) 02004DOI: https://doi.org/10.1051/e3sconf/202015602004