Deterioration Mechanism and Statistical Damage Constitutive Model of Red-Bed Soft Rock with Different Moisture Content

The mechanical properties of red-bed soft rock, commonly encountered in the Central Yunnan Water Diversion Project, deteriorate significantly upon contact with water, impacting the project’s safety. This study investigates the effects of moisture content on the mechanical properties of red-bed soft rock by conducting triaxial compression tests under varying confining pressure. Degradation mechanisms associated with different moisture content levels are identified, and deformation and deterioration mechanisms are examined through mineral compositions using X-ray diffraction. Modifications to the Drucker-Prager criterion are explored to incorporate the Lode parameter. Using the Weibull distribution, a statistical damage constitutive model for red-bed soft rock is established. The triaxial compression test results of red-bed soft rock are used for model validation, demonstrating a strong agreement between the theoretical model and empirical findings, confirming its suitability for analyzing the mechanical behavior of red-bed soft rock under varying moisture content. The findings of this paper provide valuable insights for investigating large deformations in red-bed soft rocks within the context of Central Yunnan Water Diversion Project.