| As is known, in environment of high temperature, physical properties of rocks are crucial important, In tertiary oil recovery, the in-situ combustion method is adopted to decrease the viscosity of oil and induce rock cracking, then the permeability of the reservoir is increased. Deep geological disposal of high-level radioactive waste(HLW) is a study focus of America and France. They pay their attention to disposal of HLW in granite reservoir, but the question is that after thermal cracking, the area of HLW may be connective to the groundwater, which threats the living environment of human beings. Simultaneously, the surrounding rock of HLW disposal repositories, the key part of which absorbs the radionuclide and retard its transport, changes its mechanical properties and mechanical behavior in high temperature, which possesses crucial effects on the location choosing, design, and safety prediction of HLW disposal repositories, and it is one of the majors of study. In the exploration of geothermal, geothermal is gotten from hot rock above 300 ℃. Because of the decrease of the temperature, rock cracking happened. In addition, the underground deposition of fluid, the study and simulation of crust evolutionary process are relative to rock cracking study, and the physical mechanical properties of rock change under high temperature. So it has important engineering value to study the effects of hot cracking and changes of rock physical mechanical properties to deposition of HLW, exploration of geothermal and other deep exploration questions. At present, rock cracking numerical tests are often limited on deformation, cracking and physical properties of rock, and the studies on physical mechanical properties of rock mainly depend on in-situ observation and experimental test. In-situ observation is necessary to engineering, but it is often limited by field environment, personnel and finance, so it is not much effective. Up to now, numerical tests of rock hot cracking and rock physical mechanical properties are not studied. Because of the non-homogeneity, non-continuum and complexity of geometry structure of rock, the analysis methods lack of effective technique to describe this question exactly. The coupled mathematical model and its finite element numerical equations of random media are established considering the random non-homogeneity and the coupling effects of deformation, temperature, and the numerical tests' simpleness. It provides important theory and practical values to adopt the numerical tests. In this paper, from the point of non-homogeneity of rock, the micro-structure statistical characterization and penetration theory on physics are introduced to study the following contents.1. Considering the physical mechanical properties' random non-homogeneity, the thermoplastics model and coupled solid-thermal numerical model of random media are established and the finite element numerical method is educed. The equations and the methodsare basis of the study of rock hot cracking.2. The plane axis-symmetrical and spherical axis-symmetrical questions of random media's thermal-elastic model is analyzed, the technique of rock physical mechanical parameters as random variables is provide, and the analysis solutions are attain under the distributions of Gauss, Weibull and index, hi addition, the solution of random media's plane axis-symmetrical solid-thermal mathematical model, including displacement, deformation and thermal stress.3. Under the four random distribution (Uniform, Gauss, Weibull and index), 2-D random non-homogeneity thermoplastics-plastic model and high temperature, the effluence of thermal dilatability on thermal cracking law and temperature threshold is studied in detail, and the result provides the rock thermal cracking law and temperature threshold changing with the changing of distribution of parameter m and some conclusions are obtained. Hot to break threshold up to and distribute parameter rise by the increases of m by value temperature rock, Present power function or the straight line rela...
|
PDF Full Text Request