A Statistical Constitutive Model considering Deterioration for Brittle Rocks under a Coupled Thermal-Mechanical Condition

Abstract

Due to active actions of groundwater and geothermal, the stability of underground engineering is important during geological structure active area. The damage mechanical theory and statistical mesoscopic strength theory based on Weibull distribution are widely used to discuss constitutive behaviors of rocks. In these theories, a statistical method is used to capture mesoscopic properties of rocks in order to generate a realistic behavior at a macroscopic scale. Based on the above theories, this paper aims at establishing a constitutive relation of brittle rocks under thermal-mechanical coupling conditions. First, a statistical damage constitutive model was established by considering the thermal effects and crack initiation strength. Subsequently, the parameters of the model were determined and expressed according to the characteristics of stress-strain curve. Third, the model was verified by conventional triaxial experiments under thermal-mechanical actions, and the experimental data and theoretical results were compared and analyzed in the case study. Finally, the physical meaning of the parameters and their effects on the model performance were discussed.

Macro/meso failure behavior of surrounding rock in deep roadway and its control technology

“…Considerable efforts have been devoted to the related researches. For example, Gao et al (2018) established a statistical constitutive model by introducing a three-parameter Weibull distribution. Based on the adequate assumption of rheological components, the constitutive relation of the rheological model under the thermal and mechanical coupled effects of deep rock was discussed (Fig.…”

Mechanical Properties and Statistical Damage Constitutive Model of Rock under a Coupled Chemical-Mechanical Condition

“…A reasonable constitutive model is a useful method to investigate the damage evolution behavior of materials [24][25][26]. In recent years, many damage constitutive models have been established based on various strength theories or criterions, such as rock strain strength theory [27][28][29], Drucker-Prager (D-P) criterion [30][31][32][33], Mohr-Coulomb (M-C) criterion [34][35][36][37], and Hoek-Brown (H-B) criterion [38,39]. However, the strength of microelements, which is affected by many factors, cannot be calculated accurately using the strain strength theory [39].…”

Laboratory Investigation and Modelling of the Thermal-Mechanical Properties of Soil in Shallow Mineralized Groundwater Area

“…Laloui and Donna [14] and Zhang and He [15] emphasized the importance of thermal conductivity because it is the only soil thermal property that can directly determine the heat transfer process in soils comparing with thermal diffusivity and heat capacity properties. Gao et al [16] established a constitutive relation of brittle rocks under thermal-mechanical coupling conditions.…”

“…However, there are few studies available on both thermal and mechanical properties of saline soils that have combined actions on the performance of the geothermal subsurface structures [16]. Thermal conductivity is an intrinsic soil property that describes its ability to conduct heat and is affected by several factors including moisture content, dry density, soil mineral components, and salts.…”

“…: 0 mol/kg M: 1.5 mol/kg M: 3 mol/kg M: 4.5 mol/kg M: 6 mol/kg C: 0 mol/kg C: 1.5 mol/kg C: 3 mol/kg C: 4.5 mol/kg C: 6 mol/kg Elastic shear modulus (GPa) Applied vertical stress (kPa) Validation of the G 0 model under different salinity conditions. M: measured values; C: calculated values 16. Geofluids mass of added salt (M), salt concentration (θ), and moisture content (ω) were incorporated into grain shape coefficients g as , g bs , and g cs of F s : g as = g bs = lg e M•θ•ω…”