低温下岩土体非整数阶元件组合蠕变模型研究

发布时间：2018-01-06 09:01

  本文关键词：低温下岩土体非整数阶元件组合蠕变模型研究　出处：《安徽理工大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 冻结岩土 本构关系 泥岩 蠕变 分数阶导数 西原蠕变

【摘要】：不同的岩土体在不同的环境下,其蠕变特性不尽相同,很多学者已经在软岩土和岩石领域做了大量的土工力学试验和总结,例如黏土、黄土等,多集中在岩土的抗压稳定性和流变性方面,运用的方法和理论也是千差万别,但受制于理论模型的选用及优化处理的复杂性,在冻结泥岩、硅藻泥岩等的蠕变研究方面,特别是模型的构造及参数的优化处理上还存在着一定的研究余地,正因于此,为了得到一种能够更加精确描述东北地区深层冻结岩土体的蠕变特性规律的西原蠕变模型,特选取了该地区具有代表性的岩土试样——泥岩、硅藻泥岩作为分析对象,鉴于其在现场复杂的环境(主要考虑低温)及地质条件下将会产生预想不到的蠕变变形,分析其受温度、荷载、土质类别以及时间等因子的影响显得尤为重要。合理的岩土本构关系是应该建立在大量的有针对性的蠕变试验基础之上,结合必要的元件模型理论以及引入新的算法和分数阶导数理论,建立特定元件模型来研究和分析其力学性质。利用自行研制的冻土试验机对试样在三种温度水平(-5℃、-10℃、-15℃)和三种加载系数(0.3、O.5、0.7)下展开强度和蠕变试验,分析其与各种环境因子的影响并进行相应蠕变模型的拟合比较,进而得到适用的模型参数。以整数阶西原蠕变模型为基础,’选取改进的模拟退火优化算法进行优化处理,得到分数阶西原蠕变模型,该模型的参数具有易处理的特点,形式相对简单,具有一定的统一性。通过对比整数阶西原蠕变模型和优化后的分数阶导数西原蠕变模型,可以发现后者在蠕变模拟的全阶段都具有很高的相关性,特别是在模拟曲线的拐点附近。另外,在计算过程中需要调整的参数也比较少,充分说明了分数阶导数西元蠕变模型的合理性,且在现场施工领域具有不可否认的蠕变预测预判之工程意义。
[Abstract]:Different rock and soil in different environments, its creep characteristics are different, many scholars have done a large number of geotechnical tests and summary in the field of soft rock and rock, such as clay, loess and so on. Most of them focus on the stability and rheology of rock and soil, and the methods and theories used are different, but they are restricted by the complexity of the selection of theoretical model and the optimization of treatment, so they are frozen mudstone. There is still some room for study on the creep of diatom mudstone, especially on the structure of the model and the optimization of the parameters, which is the reason. In order to obtain a new creep model which can more accurately describe the creep characteristics of deep frozen rock and soil in Northeast China, the representative geotechnical sample-mudstone in this area is selected. In view of the complex environment (mainly considering low temperature) and geological conditions, diatom mudstone will produce unexpected creep deformation, so it is analyzed that it is subjected to temperature and load. The influence of soil type and time is particularly important. A reasonable constitutive relation of rock and soil should be established on the basis of a large number of targeted creep tests. Combined with the necessary component model theory and the introduction of a new algorithm and fractional derivative theory. A specific element model was established to study and analyze the mechanical properties of the samples. The test machine was used to test the samples at three temperatures (-5 鈩，

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