Many environmental protection projects are under alkaline conditions, and polypropylene spunbond needle-punched geotextiles must be used, such as: tailings dams and heap leaching of various metal beneficiation (gold, silver, copper, molybdenum, aluminum, magnesium, Lead, zinc, etc.) landfills, special landfills, fly ash landfills, ash dam pools, heap leaching sites, red mud siloes, etc., are all under acid and alkaline conditions. Polyester geotextiles will be gradually corroded and decomposed under alkaline conditions, and the strength will drop sharply, causing hidden dangers to engineering safety, while the good chemical stability of polypropylene spunbond needle-punched geotextiles can well ensure the quality of the project and avoid hidden dangers of engineering safety. , reduce maintenance costs.