Numerical simulation of creep fracture evolution in fractured rock masses

Abstract

The initiation, expansion, and penetration of microscopic cracks in rock is the macroscopic manifestation of creep. This paper investigates mechanical creep characteristics and fracture evolution processes in rock masses with different fracture angles, lengths, and rock bridge dip angles. Single fractures, dual parallel fractures, and fracture groups are considered. The approach comprises discrete element simulation based on continuum mechanics, utilizing the continuous and discontinuous software, GDEM. Single-fracture rock masses are characterized by a progressive fracture development mode dominated by tensile shear failure. The rate of creep and fracture magnitude both increase according to fracture length. With increasing fracture inclination angle, creep rate and fracture magnitude increase and decrease. The creep rate and degree of rupture are highest for fractures inclined at 30°. The dual-fracture rock mass exhibits both tensile crack failure and compressional shear failure. Creep rates are highest, and rupture effects are most apparent at rock bridge inclination angles of 90°. If the rock bridge is too long or too short, the stable creep stage is prolonged, but the creep acceleration stage intensifies due to interaction between fracture-bounded rock masses. The failure mode, in this case, involves collective failure by tension fractures and compressional shear. Creep rate and fracture magnitude increase with the number of fractures, which accelerates rock mass deformation to a certain extent. However, when the number of fractures reaches a certain threshold, a relatively stable structure may become established, slowing down the creep rate, especially during the creep acceleration stage. This study can provide a theoretical basis and reference for investigating the creep rupture law of rock mass engineering and the prevention and control of fractured rock mass geological disasters.

Failure characteristics of thick hard roof stratum under hydraulic pre-splitting and its application in a coal mine, Dongsheng mining area

“…In geotechnical engineering, oil and gas, water conservancy, machinery, and other fields, it is generally applied to realize multi-physics couplings such as seepage field, temperature field, and solid field (STS) (Li et al, 2021;Na et al, 2022;Pei at al., 2021). Considering the inherent advantages of this software, we employ it to establish a twodimensional geological model based on the detailed investigations of geologic conditions in the study area as illustrated in Fig.…”

Failure Characteristics of Thick Hard Roof Stratum under Hydraulic Pre-splitting and Its Application in A Coal Mine, Dongsheng Mining Area

“…In geotechnical engineering, oil and gas, water conservancy, machinery, and other fields, it is generally applied to realize multi-physics couplings such as seepage field, temperature field, and solid field (STS) (Li et al, 2021;Na et al, 2022;Pei at al., 2021). Considering the inherent advantages of this software, we employ it to establish a twodimensional geological model based on the detailed investigations of geologic conditions in the study area as illustrated in Fig.…”

Simulation analysis of the evolution law of creep rupture crack extension in X-fractured rock body

“…The random distribution of fissures within the rock makes them difficult to analyze theoretically or study experimentally. Parallel fissures have been simulated [1]. Numerical simulation was used in this study to examine the creep rupture process of rock bodies with non-parallel fissures.…”

“…Chao et al [2][3][4] carried out creep tests on single-fissure sandstone at different angles and considered the creep characteristics of hard rock under different characteristic stress intervals to explore the creep characteristics of intact rock and fissure-containing rock. Zhao et al [5] used the sliding wing crack model and the MAPLE software to analyze a single-fissure rock body under a constant load and describe the influence of the fissure angle and length on the creep deformation. Luo et al [6] analyzed the shear creep characteristics of the structural surface of a natural red sandstone rock body through three-dimensional morphology scanning of the structural surface and the graded-loading shear creep test.…”