“…The normalized horizontal surface displacement, the normalized vertical surface displacement, and the surface vertical stress generated by the proposed technique are reported in Figures 14, 15 clearly illustrated in Figure 14 and Figure 15. This finding also confirms the conclusion of the various previous researches on that the presence of surface stresses or surface energy renders the material stiffer (Zhao and Rajapakse, 2009, Intarit et al, 2010, Intarit et al, 2011, Zhao and Rajapakse, 2013, Tirapat et al, 2017, Tarntira, 2018. Similarly, as the ratio / s increases, the vertical stress at the free surface of the bulk reduces over the loading region and becomes larger outside of the loading region.…”