Rock constitutive model based on damage partition and unified strength theory

Almost all the rocks in a nature internally contain damage to a certain extent. The proceeding of damage evolution will lead unstability of rocks because of crack coalescence. In this paper, the rocks are divided into three parts, e.g., the undamaged part, the closed crack part and the open crack part. Then, a compatibility analysis of deformation was conducted, and the damage constitutive model and the damage evolution model were proposed based on unified strength theory and statistical damage theory. The models were verified by tested results of triaxial compression test of purple mudstone in Badong formation. Finally, the models were applied to analyse the damaged depth of one anticlinal bedded rock slope. Results indicate that the damage constitutive model corresponds with tested results, e.g., the triaxial stress-strain feature. Also, the damage evolution model well reflects the damage process of samples and the model parameters process distinct physical meanings. Besides, the modified damaged depth model of anticlinal bedded rock slope is more conservative and will bring safety to geotechnical engineering design.