WANG X, LIU X Y, ZHENG S H,et al.Mechanical properties and statistical damage model of rock mass with different fracture persistence[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):159-169.

doi:10.16186/j.cnki.1673-9787.2025030020

Received:2025/03/11

Revised:2025/05/19

Published:2026/06/17

Mechanical properties and statistical damage model of rock mass with different fracture persistence

Wang Xin, Liu Xiaoyu, Zheng Shihang, Yuan Chao

Xi’an University of Science and Technology， Xi’an 710054， Shaanxi， China

Abstract: Objectives To investigate the deformation and failure characteristics of rock mass under the influence of fracture persistence and confining pressure， triaxial compression tests were conducted on rock specimens. Methods The evolution laws of mechanical properties and mechanical behaviors of fractured rock mass were analyzed. The coupled effects of fracture-induced damage and load-induced damage， as well as the resulting macroscopic mechanical responses， were theoretically characterized.  Results The results show that as confining pressure increases， the peak point of the stress–strain curve shifts to the right， the post-peak softening segment declines more gently， and the plastic behavior becomes more pronounced. Confining pressure promotes rapid activation of defects， inducing microcracks to propagate and coalesce around pre-existing fractures and specimen ends， ultimately leading to macroscopic rock failure. With increasing fracture persistence， tensile strains gradually transform into compressive strains， and the rock undergoes tension–shear composite failure. The tensile failure observed in stage Ⅱ is essentially the result of the combined coalescence of secondary shear cracks and tensile cracks. An expression relating the total damage of rock mass under loading to the superposition of the two damage components was established. Using statistical damage theory and the D-P criterion， a damage constitutive model for fractured rock mass was developed to describe the nonlinear effect of fracture persistence on rock damage and failure. The physical meanings of the model parameters were clarified： m represents the brittleness characteristics of the rock mass， and F₀ reflects its average strength. Both m and F₀ show a decreasing trend with increasing fracture persistence. The variations in these parameters， reflecting changes in ductility–brittleness and strength characteristics of the rock mass， are consistent with the experimental results， thereby validating the proposed model. Conclusions The findings provide a theoretical basis for evaluating the stability of fractured rock mass engineering projects.

Key words:fracture rock mass;confining pressure;deformation and failure;damage evolution;constitutive model