【作者】 莫瑞；

【导师】 曹文贵；

【作者基本信息】 湖南大学 ， 岩土工程， 2008， 硕士

【摘要】 岩土应变软硬化变形过程模拟是岩土力学研究的重要内容。统计损伤理论的发展已为其开辟了一条良好的研究思路与途径。但是,目前利用统计损伤理论建立的岩土损伤本构模型存在一定不足,既不能反映复杂应力状态影响的岩土应变软硬化变形过程,也不能反映岩土变形过程的体积变化特性,而且,模型参数物理意义也不明确,须对此进行深入探讨,以完善岩土变形过程模拟研究的内容。因此,本文就此展开研究,具有重要的理论与工程实际意义。本文内容主要包括岩石和饱和土应变软硬化变形过程模拟方法。其一,在考虑岩石屈服或破坏后仍具承载力特征的岩石损伤模型研究基础上,假定岩石微元强度服从正态分布,利用统计损伤理论,建立出岩石应变软硬化变形全过程模拟的损伤模型及损伤统计本构模型,并通过探讨岩石应变软硬化过程的特点和模型参数与岩石应力应变曲线特征参数(峰值点强度和应变等)之间的关系,提出了岩石应变软硬化统计损伤本构模型参数确定方法,该模型具有参数物理意义明确、易于确定和适用于复杂应力状态的特点;其二,在岩石损伤模型研究的基础上,结合饱和土有效应力原理,提出了反映饱和土损伤力学机理的新型损伤模型,据此,采用统计损伤理论,并引入体积变形模量,针对饱和土三种试验条件,分别建立出反映饱和土变形过程的统计损伤本构模型,该模型能充分反映饱和土变形过程的体积变形的影响;其三,利用饱和土三轴试验曲线和已有岩石三轴试验曲线,对本文模型进行了实例分析,验证了本文模型的合理性。本文研究成果较现有同类研究成果明显具有优越性,完善了岩土应变软硬化变形过程模拟方法。更多还原

【Abstract】 The simulation of the deformation process of geo-material in hard-working status or in soft-working status, is the emphasis of the research of the mechanics of geo-material. The development of statistical damage theory provides an effective idea and approach for it. But there are some defects in the damage constitutive models of geo-material based on this theory, it can’t reflect the strain softening-hardening deformation process of geo-material under complicated stress and the characteristic of volume change in the stress-strain process of geo-material, furthermore, physical meaning of the model’s parameters isn’t definite. To improve the research of the simulation of the deformation process of geo-material, further investigated is needed. For these, study was developed in this paper to solve the problems, which is of great thoeratical and practical significant.The means of the simulation for the strain softening and hardening deformation process of rock and saturated soil is the major content. Firstly, on the base of the research of the rock’s damage model which considers the bearing capacity of rock after its yielding or failure, according to the law that micro-unit strength of rock accorded with normal distribution, and statistical damage theory, the damage model and the statistical damage constitutive model which can simulate the deformation process of rock are set up. By studying the characteristic of the softening and hardening process of rock and discussing the relationship between the model’s parameters and the characteristic of the stress-strain full curve for rock such as the stress and strain at the peak-stress point, the way for determining the parameters of the rock’s constitutive model is set up. The model’s parameters indicate physical meaning, which is easy to determinate and suitable for complicated stress. Secondly, based on the rock’s damage model, combined with the effective stress theory, the damage model that reflects the damage mechanics of saturated soil is established. On the base of the statistical damage theory and volume deformation modulus, the corresponding statistical damage constitutive models of saturated soil are built in accordance with three different test conditions for saturated soil, which can describe the effect of the volume compress under the deformation process of saturated soil. Thirdly, the rationality about the constitutive models of geo-material have been shown in comparison with the results of the tri-axial tests of saturated soil and the existing curve of tri-axial tests of rock.Compared with the existing similar results, the research in the text obviously has superiority, which completes the method of simulation on the strain softening and hardening process of geo-material.更多还原