Feasibility of protecting earthen sites by infiltration of modified polyvinyl alcohol

Weathering has long been a focus of study for the earthen sites in northwestern China. The primary aim of this study is to investigate the feasibility of protecting earthen sites with modified polyvinyl alcohol (SH) through borehole grouting. First, the effective protection region of SH is determined by hardness analysis, a control experiment, and scanning electron microscopy (SEM). Then, the characteristic changes obtained by SH infiltration with respect to effective protection radius, infiltration rate, hardness and grouting volume are discussed for soil specimens with different dry densities and different hole diameters. The results indicate that when soil specimens are cured for five days after borehole grouting, their surface hardness is stable and the protective effect of SH is remarkable. When the dry densities and hole diameters of these soil specimens are less than 1.50 g/cm(3) (void ratio e > 0.779) and equal to 5 mm, respectively, the protection and infiltration effects of SH are relatively good. The protected depth with surface spraying alone has been verified to be insufficient for anti-weathering. Finally, the feasibility of protecting earthen sites with SH by infiltration is discussed preliminarily, and it is suggested that the advantages of surface spraying and borehole grouting for anti-weathering should be combined to protect the earthen sites. (C) 2019 Elsevier Ltd. All rights reserved.