Rock Macro-and Meso-damage Composite Theory And Applied Research

The macro-and meso-damage composite model has been obtained through integrating the microcosmic datum quantum which reflecte the inner damage disfigurement and mechanism of its changing with the macrocosmic datum quantum which reflecte macro behave of rockmass inner damage piling up during a periord. The damage rock stress-strain curve under uniaxial and triaxial compression and the relationship of rock characteristics points have been analysed. The dissertation analyses the rock microcrack density expanding law and the influences on macro variable from macro-damage and meso-damage, The macro-tests and meso-tests of rock have been compared with calculating and analyzing, in turn the rock mass damage have been analyzed, Based on the relationship of macro-and meso-damage parameters and the correlations of rock characteristics points, the adjoining rock damage of deep circle cavern has been analysed.The main thesis works are the following parts:1) Using microcrack density which is used to discribing the macro-mechanics properties in meso-damage mechanics as the describe parameters of damage state on continuous damage theories, this dissertation makes the variation relation between double scalar quantity model and the crack density. Assuming that the element has three states,i.e. failure, damage and intactness, this dissertation unite the macro-damage statistical theory and meso-damage theory, establishes a macro-and meso-damage composite model.2) This model can be used to describe the relation between the stress-strain of rock and the microcrack density. The dissertation analyses the rock microcrack density expanding law under uniaxial compressive test by examples, discusses the relations between the microcrack density and the stress - strain of rock, the differences and influences of the f being obtained by the Taylor method, the generalized self-consistent method and the Taylor medium method in the process of stress-strain. The relationship of rock characteristics points has being analysed. The method has been set up to determine the residual strength of rock with meso-damage theory;3) This dissertation draws to the macro-and-meso damage composite model of rock, and the model is expressed with single scalar and double scalar under stiaxial compression. The rock stress-strain curve calculating formula under stiaxial compression is deduced with uniaxial anti-compression indicators.4) According to the above work, the tests of rock uniaxial compression and triaxial compression have been completed, and the scanning electron microscopy test and CT results have been compared with calculated and analyzed. 5) The method of determining parameters is set up on the damage model to expressthe rock stress-strain curve. The law is discussed of rock deformation modulus varying with surrounding pressure, and the formula being denoted with exponent formula is deduced about the relationship between the deformation of rock E and surrounding pressureΔσ3, and it expresses the character that the parameter of crack density decreases with the surrounding pressure increases.6) Using meso-damage mechanics method it is to set up the relationship between the microcrack density parameters and rock integrality coefficients or volume joint quantities. By the Taylor method, the generalized self-consistent method and the Taylor medium method, this dissertation analyses and compares the differences in determining rockmass parameters on crack density and their reciprocities. The method to determine the crack density of rockmass has been introduced through the geological investigating statistical method, the intactness index of rock mass method or the elastic wave equation method.7) Accouding to the rock stress-strain curves, the deformation of the rock surrounding cavern can be divided into the four states of the elastic zone and the plastic hardening damage zone and the plastic softening damage zone and the fracturing zone. Based on the relation among every characteristic points and the Mohr strength theory, the calculating formulas on damage have been established of rock surrounding cavern partition radius, the rock surrounding cavern pressure and the rock surrounding cavern deformation.