Abstract: To prevent the geotextiles in tunnel waterproofing and drainage from crystal blockage, a hydrophilic surfacemodification test of geotextiles is conducted based on the surfacemodification technology. In addition, the feasibility of these modified geotextiles to slow down the formation of calcium carbonate crystal blockages is explored. The results reveal that: (1) 〖JP2〗By using the surfacemodification method, the geotextiles modified by polyethylene glycol(PEG) and silica sol are prepared, and the two hydrophilic substances can be better attached to the fiber surface, thus improving the hydrophilicity and permeability of the geotextile. (2) After nonionic particles are attached on the surface of the two modified geotextiles, the drainage capacity of the geotextiles is improved, thus relieving the crystallization blockage phenomenon. (3) The scaleresistance rate of the two modifiers on the three geotextile materials is manifested in the following order: composite geotextile > filament geotextile > staple fiber geotextile. In addition, the scaleresistance rate of the geotextile modified using PEG is 20%~30% higher,  thus showing a better relief effect of the crystallization blockage.

Key words: karst tunnel, geotextile, calcium carbonate crystals, hydrophilic surface modification, penetration performance