Unconfined strength of an unsaturated residual soil struck lightningThiago de S. Carnavale, Mariana F.B. Motta, Tácio. M.P. de Campos, Haimon D.L. Alves, Antônio R.M.B. de Oliveira and Hélvio J.A. MartinsE3S Web Conf., 9 (2016) 14006DOI: https://doi.org/10.1051/e3sconf/20160914006