Abstract:The effects of drying-wetting cycles on the mechanical properties and meso-mechanism of the hydrophilic polyurethane material(W-OH) solidified Pisha sandstone were conducted to provide scientific basis for the study of W-OH consolidation amending Pisha sandstone and its durability. W-OH was used to consolidate the Pisha sandstone in this study. Macroscopic mechanical properties of the W-OH solidified Pisha sandstone were tested by unconfined compression experiment and triaxial compression experiment. To obtain the meso-mechanism, SEM, EDS and weighing methods were used to analyze the microstructure, elements, and quality losses of the sample after drying-wetting cycles. The results showed that unconfined compressive strength, elastic modulus, and cohesion of the W-OH solidified Pisha sandstone increased after drying-wetting cycles of 1~3 times. During drying-wetting cycles of 3~9 times, the mechanical strength of the W-OH solidified Pisha sandstone decreased. the rest solidified W-OH with high cohesive forces remained on the surface of the Pisha sandstone particles and the mechanical strength tended to be stable after drying-wetting cycles 9 times. The internal friction angle varied with fluctuation from 1 to 9 time drying-wetting cycles and stabilized after 9 times. The W-OH loss in the solidified soil samples was evaluated by the carbon element analysis and mass loss analysis. The solidified W-OH gradually decreased during drying-wetting cycles of 1~9 times and became stable after 9 times, which proved meso-mechanism of macroscopic mechanical properties above-mentioned and provided theoretical basis for long-term characteristics of W-OH consolidated Pisha sandstone. The results of this study suggest that the mechanical properties of W-OH solidified Pisha sandstone after 9 drying-wetting cycles can be considered as the long-term mechanical properties of this material.