Potential of potassium silicate reinforcement technique for earthen relics protection in moist areas regarding shear strength of unsaturated soil

The protection of earthen relics in moist areas is a key issue of cultural heritage conservation, Potassium Silicate (PS) infiltrated reinforcing the earthen relic is also a hot issue. PS is infiltrated into soils under constant pressure and reacts with clay mineral to protect earthen relics. But the effect of PS reinforcement may be different because of high degree of saturation in moist areas. In this paper, two series of specimens were designed to investigate the potential of PS reinforcing the soils with high degree of saturation, mainly focusing on shear strength of unsaturated soils at constant water contents. The specimens are made by compaction at the specific water content. After that, the gravimetric water contents of specimens are controlled at 13% 17% 19% 21% and 25%. One group of specimens is directly sheared at constant water contents using direct shear apparatus under 100kPa and 300kPa, the other group is reinforced by PS and then sheared at the same water content under same vertical pressure. According to the soil-water characteristic curve derived from the mercury intrusion porosimetry test, the shear properties of two groups are summarized and analyzed at different initial matric suctions. These results justify that PS can reinforce earthen relics in moist areas.