NUMERICAL INVESTIGATION OF THERMAL STRESS AND FAILURE PROCESS OF ROCK INDUCED BY THERMAL MISMATCH
Thermal mismatch induced thermal stresses are identified as one of the major causes of rock failure. When temperature changes are taken into account, the large differences of thermal expansion coefficients which occur in the several mineral of rock lead to severe thermal or residual stresses, and cause it breakdown. In this paper, a numerical model, RFPAT code, is presented for thermal stress analysis and failure evolution reappearance of rock induced by thermal mismatch stress (TMS). Different from other numerical models, rock sample is considered heterogeneity and the failure process which occurred in the whole thermal loading can be modeled. To describe the remarkable character of rock at mesoscope level, i.e. heterogeneity, a statistical method, Weibull distribution, is employed. And apply the damage mechanics method to model the failure evolution processes. The method gives an elementary explanation why damages occurred when rock exposure to high or low temperatures, and with the presented method, its easy to identify the location where cracks are most likely to initiate and propagate. The numerical results indicate that the presence of thermal mismatch causes stress concentration along the interface of those minerals, and the stiffer the minerals, the higher the stress concentration. Crack patterns show that if the thermal expansion coefficient of embedded mineral is smaller than that of the surrounding minerals, during temperature increase, θ-cracks will generated, and radial-cracks emerged when temperature decrease. The results obtained from RFPAT code show a good agreement with experimental evidence for crack patterns caused by thermal expansion mismatch.
S.B.Tang C.A.Tang G.Lin L.C.Li T.Xu
Center for Rock Instability and Seismicity Research, Dalian University of Technology, Dalian 116024, Center for Rock Instability and Seismicity Research, Dalian University of Technology, Dalian 116024, Research Center for Numerical Tests on Material Failure, Dalian University,Dalian 116622, P.R.China
国际会议
南京
英文
718-726
2006-05-22（万方平台首次上网日期，不代表论文的发表时间）