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

Abstract

The mechanical properties of red-bed soft rock, widely encountered in the Central Yunnan Water Diversion Project, deteriorate significantly upon contact with water, impacting the safety of the project. The objective of this paper is to investigate 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 distinct moisture content levels are determined. Deformation and deterioration mechanisms are investigated from the mineral compositions using X-ray diffraction. Modification of the Drucker-Prager criterion is studied to incorporate the Lode parameter. Utilizing the Weibull distribution, this study establishes a statistical damage constitutive model for red-bed soft rock. The triaxial compression test results of red-bed soft rock are used for the purpose of model validation. It is demonstrated that there is a strong concurrence between the theoretical model and empirical findings, indicating its suitability for analyzing the mechanical behavior of red-bed soft rock under varying moisture content. Findings in this paper can provide valuable insights into the investigation of large deformation occurring in surrounding red-bed soft rocks within the context of Central Yunnan Water Diversion Project.