【作者】 郑剑峰；

【导师】 汤爱平；

【作者基本信息】 哈尔滨工业大学 ， 岩土工程， 2011， 硕士

【摘要】 基于冻土复杂多变的物理力学性质对冻土区防灾减灾和工程建设中举足轻重的影响,以及近年来基于冻土蠕变,应力松弛和长期强度等宏观的流变性质和基于微细观结构观测的颗粒位错,重新定向和微裂纹萌生导致各向异性等微细观的损伤性质的研究,考虑不同加载方式的流变和损伤的性质的系统而理论的建构还没有形成,故而本文着力于对不同加载方式下的冻土的流变和损伤性质进行研究。本文对冻土流变的蠕变,应力松弛,流动和长期强度性质根据衰减和非衰减蠕变的不同规律展开论述并得到了下述结果。1、从理论上进行定性分析冻土蠕变。2、针对不同的流变理论分别以老化理论,遗传蠕变理论,硬化理论和流动理论为分析对象通过数学几何方法描述其适用性及其规律特点,根据同样反映相应性状的前人的实验数据及其得到的相关经验关系式分析其大致应力应变性状并得到了应力应变在位移加载方式下的随时间发展的大致规律。3、运用其归一化的方法和原则,提出具有一定实践意义的冻土长期强度的归一化模型,并借玉前人研究之实验资料分析冻土的长期强度特性,然后提出理论上的冻土长期强度的函数。4、基于损伤的基本理论通过引入冻土损伤张量,从静荷载和动荷载下推导考虑冻土损伤的弹塑性各向异性损伤应力应变关系理论,并推导得到了其有限元迭代格式,而后进行了数值分析与模拟,得到软化段的应力时程性状规律与理论分析一致。5、在加载时间比较短的时候,冻土流变特性并不明显,高次项的影响在时程曲线的后段将起的作用使流变特性变得突出。6、短时间加载内并不能体现出应力松弛的特点,这与长期强度的发展特性是相一致的。更多还原

【Abstract】 Based on the research of multiple physical and mechanical properties offrozen soil decisively impact on the both disaster prevention and mitigationand engineering construction, the study of rheological and damage propertiesof frozen soil have got a great progress in recent years, however, it has stillnot formed that systematic construction of rheological and damage propertiesof frozen soil based on different loading methods, so, this research focus onthe different loading methods of rheological and damage properties of frozensoil.Firstly, the qualitative analysis of the frozen soil creep in theory isdiscussed.Secondly, based on the analysis of general frozen rheological theory, therules of Stress-strain relationship of different loading methods includingaging theory, genetic theory of creep, hardening theory and flow theorythrough mathematical and geometric diagram.Thirdly, according to the result of previous’ experiments,as well as use ofnormalization methods and principles, different Characteristics of differentmodels of different models is got.What is more, through use of experimentaldata of previous researchers, this paper proposes a new model of somepractical significance of long-termed strength based on normalizationmethods and principles.Fourth, with the appliance of complex membranes scanning electronmicroscope of fine view study of frozen soil, this paper lead in the tensor ofdamage of frozen soil based on the basic theory of damage, in addition, itconducts the derivation of the formula of elastoplastic stress-strain anisotropyrelationship, to move forward a single step, the derivation of iterative schemeof finite element of frozen soil is also got. Then, after the starting of thenumerical analysis and simulation,according to the result of mumericalanalysis and simulation, the paper discusss the relationship between stress andtime in detailed更多还原