GB/T 17635.1 - 1998 Direct shear test determination of friction characteristics of focused Geotextiles and related products. The standard details sample preparation, including dimensions, cutting requirements, etc., specifies the specifications and commissioning methods of direct shear test equipment, and specifies the test operation process, such as loading rate, shear displacement and other key links. It also specifies the calculation and representation of results. Friction characteristics affect the application effect of Geotextiles in engineering. This standard provides unified test specifications for all parties involved in the production, testing and engineering application of Geotextiles, helping to ensure the Stability and Reliability of Geotextiles in engineering practice, and promoting the development of industry standardization.