A statistical damage constitutive model of rocks considering the variation of the elastic modulus
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摘要: 为建立更为完善的岩石统计损伤本构模型，针对现有模型难以反映某些岩石在三轴试验条件下弹性模量随围压变化而改变的特性，从不同类型空隙对岩石变形性质的影响入手，深入分析了岩石弹性模量变化的机理，并在此基础上，依据弹性参数与岩石中未闭合裂隙数的关系建立了岩石弹性模量变化的分析方法。之后，引入统计损伤理论，考虑损伤阈值的影响和残余强度变形特征，建立了可模拟岩石变形全过程的统计损伤本构模型，并给出了基于三轴压缩试验曲线的模型参数确定方法。本文模型可反映岩石弹性模量随围压变化而改变的特性，且具备现有模型的优点，对岩石变形全过程模拟效果良好。最后，通过试验曲线与本文及同类模型理论曲线的对比分析，表明了本文模型的合理性与优越性。Abstract: In order to establish a more advanced statistical damage constitutive model for rocks, this paper contraposed the deficiency that current models have difficulty in reflecting the characteristics that the elastic modulus would vary with the confining pressures under the conditions of triaxial compression test for some certain rocks, analyzed the mechanism of the rock elastic modulus variation from the perspective of the influences of voids of different kinds on the rock deformation characteristics, and on the basis, a method to research the variation of elastic modulus for rocks has been set up according to the relationship between elastic parameters and the number of cracks which are still unclosed inside the rocks. Afterwards, by introducing the statistical damage theory and taking into account the influences of the damage threshold and the deformation characteristics of the residual strength, a new statistical damage constitutive model which is capable of simulating the complete deformation process of rocks would be built, furthermore, a method to determine the parameters in the model has also been provided based on the triaxial compression test curves of rocks. The model this paper proposed is able to manifest the rock elastic modulus variation with the confining pressure while it possesses the advantages of the existing models and is capable of simulating the rock complete deformation process satisfyingly. Finally, through the comparison analysis among the experimental and theoretical curves of the proposed model and another similar model, the rationality and superiority of the proposed model have been demonstrated.
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