Damage failure behavior and quantitative model of elastic energy action of deep gas-bearing coal-rock composite structure
DU Feng
WANG Kai
ZUO Xiaohuan
ZHANG Yi
JU Yang
SUN Jiazhi
Abstract：It is very important to understand the energy evolution behavior of gas-bearing coal-rock composite structures under the coupling of lithology and confining pressure to explore the mechanism of coal-rock composite dynamic disasters.In order to deeply understand the influ-ence of damage failure and energy dissipation behavior of gas-bearing coal-rock composite structures,the GCTS RTR-4600 high-temperature and high-pressure rock triaxial test system was used to carry out acoustic emission-seepage-damage triaxial tests on gas-bearing coal-rock composite structures with different confining pressures and lithologies.Firstly,the damage and mechanical response characteristics of the specimen were obtained,and the crack propaga-tion law was revealed by RA-AF crack correlation value in AE monitoring,and the dynamic re-lationship between the permeability and stress state of the specimen was analyzed.In addition,the effects of confining pressure and lithology on the quantitative distribution and conversion of energy are systematically discussed.Based on the law of energy dissipation,the mathematical model of energy transfer of gas-bearing coal-rock assemblage was further constructed,and the experimental data were used to verify it.The results show that the proportion of tensile crack feature points in the composite is significantly increased by the increase of rock strength,while the increase of confining pressure drives the crack propagation from tensile dominance to shear fracture.The confining pressure changes the energy distribution mode of the coal sample,and the high confining pressure shortens the energy hardening stage and prolongs the energy sof-tening stage,so that the internal energy storage of the sample can reach the saturation state faster.Based on the energy dissipation theory,the energy model(Model Ⅰ)and the energy model(Model Ⅱ)without considering the elastic energy release after the peak of the rock com-ponent are established.By introducing the root mean square error(ERMS)and coefficient of deter-mination(R2)to evaluate the error and fitting degree between the model curve and the experimental data,it is found that the constructed model is in good agreement with the experimental data,and the minimum ERMS and R2 maximum values of model Ⅰ are 0.445 and 0.993,respectively.The ERMS minimum and R2 maximums of Model Ⅱ are 0.306 and 0.997,respectively.
Keywords：gas-bearing coal-rock composite structurespermeability evolutionacoustic emission RA-AF correlationquantitative distribution of energyquantitative model of elastic energy effect
Publication Date：2025-07-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：22( 721-742 )