Study On Damage Statistical Theory For The Constitutive Model Of Geo-material

The research of the constitutive model of geo-material always is one of the most important subjects in the geotechnical engineering. The latest statistical damage theory, whose core is the damage model of geo-material based on the hypothesis of strain equivalence by J.Lemitre, provides a new thought and method for it. But this model can not reflect the load mechanism of the damage part. So this model is quite different from the engineering practice. The creative point of this research is how to build the damage model and the damage constitutive model for the geo-material which can better reflect the engineering practice. What's more, it has the important value for theory and engineering practice.Based on the improvement about the damage model of geo-material and the introduction about the statistical damage theory, the constitutive models of geo-material have been further investigated according to the difference between the mechanics characteristic of rock and that of saturated soil. As a result, the new theory and method have been created, and a series of achievements have been acquired by deep research on the constitutive models of geo-material. Firstly, aimed at the limitation of the hypothesis of strain equivalence by J.Lemitre, a new damage model of geo-material has been established by deeply investigating the mechanism of load about the failure of geo-material, and the definition of damage for the geo-material has been broadened. Secondly, above it, a new statistical damage constitutive model of the rock has been built which can reflect the rock characteristic of softening-hardening and conversion mutually with the different stress state, and the critical condition about the conversion has been determined tentatively; the corresponding statistical damage constitutive models of the saturated soil has been built in accordance with three different test condition for saturated soil, the rationality about the constitutive models of geo-material have been shown in comparison with the results of the tri-axial tests. Finally, based on the study of the essential relationship in the different form statistical damage constitutive models of geo-material, the normalized statistical damage constitutive model of geo-material has been concluded. And it has been demonstrated theoretically that this model can reflect the important characteristic of the geo-material failure even under the still pressure.