The high-modulus potassium silicate (PS) is used to protect the earthen ruins under arid weathering condition

of which protective effect is good. The earthen ruins reinforced by PS show good permeability. VJ-T and pressure plate apparatus are used to study coefficient of permeability of saturated clay and soil-water characteristic curve (SWCC) of unsaturated clay before and after reinforcement by PS. The coefficient of permeability of unsaturated clay is predicted by correlated model. The results show coefficient of permeability increases more or less under different saturated conditions after reinforcement by PS

particularly evident in sample reinforced by 7% PS. This is because that PS changes geometric figure of these particles and the degrees of roundness to a great degree

which increases effective porosity. The reaction between PS and particle surface leads to a large pore structure to some extent and particle morphology

which leads to the increase of coefficient of permeability. SEM is used to analyse the influence of clay mineral

pore structure on coefficient of permeability of unsaturated remolded clay reacting with PS. The results can validate the permeability test well.