Abstract: The current regulations in Guangdong region stipulate that the naming of weathered granite layers is based on the measured number of standard penetration blows. However, for mountainous areas, using measured standard penetration counts to divide strata can cause naming disputes. This study resolves the geotechnical designation disputes caused by significant attenuation of Standard Penetration Test (SPT) N-values in weathered granite layers during pre- and post-excavation phases in mountainous regions. Through systematic causal analysis, the research identifies variability in testing conditions as the dominant mechanism driving SPT N-value attenuation. The static load test and standard penetration test data indicate that the bearing capacity of the excavated foundation (characteristic value of 500 kPa) is highly consistent with the parameters in the survey report. This result confirms that the established geotechnical parameters can be directly used for engineering acceptance.Addressing the limitations of the current single-index classification system (solely based on in-situ SPT N-values) for granite formations, this study innovatively proposes a dynamic calibration methodology that integrates field load tests to refine the geotechnical designation and behavioral characterization of weathered granite strata. The developed approach establishes a comprehensive "investigation-design-verification" technical framework, providing transferable solutions for foundation acceptance of weathered granite layers in mountainous areas.