中国典型黄土动力特性及其参数的试验分析

【作者】 骆亚生；

【导师】 谢定义；

【作者基本信息】 西安理工大学 ， 岩土工程， 2000， 硕士

【摘要】 在分析和总结前人对黄土动力特性研究的基础上，本文依托地矿部岩土开放实验室基金项目，着眼于对我国几个典型黄土地区（西安、兰州和太原）的黄土动力特性的对比分析，根据在不同湿度状态下动三轴试验所得的资料，较为系统地从动本构关系、动模量和动强度等几个方面进行了考察。对西安黄土还探讨了不同湿度、应力状态对阻尼比特性的影响。为了进一步从实用出发探讨黄土的动、静力特性参数之间的联系以便用常规静力特性参数评估动力特性的可能性，对于上述三种典型的原状黄土又在不同湿度状态下进行了动三轴振陷资料与常规压缩、湿陷试验资料的分析。最后，以各地区黄土已有的动力特性试验资料的收集和整理为基础，探索了同一地区内黄土的初始动弹性模量以及破坏动应力与各影响因素间的经验关系。 本文的上述研究表明，在某一地区黄土动力特性研究中，重视干密度，尤其是含水量的变化是完全正确的。但对于不同地区的黄土，除考虑干密度和含水量的影响外，还必须考虑各地黄土不同结构性所构成的影响。在反映西安黄土、太原黄土和兰州黄土动、静力特性的几乎所有规律中莫不渗透着结构性的重大作用。因此，在黄土动、静力特性研究中引入结构性具有明显的必要性和紧迫性。本文提出的潜在湿陷率概念在反映同一地区黄土在其受荷变形过程中结构性的影响和不同地区黄土在其初始结构性差异的影响方面表明了一定的优越性和发展前景。 本文在仔细分析动三轴、静压缩和静湿陷等各类试验资料中得到，用静力湿陷系数予估动力振陷系数的思路在理论上与实用上并没有特殊的研究价值。黄土动力特性研究的主要精力应集中到进一步考虑结构性的影响上。它才是在较大范围内的黄土静、动力特性研究中，发掘其定性、定量特性及参数变化的关键。 本文由已有黄土动三轴试验成果的搜集与整理找到了黄土的破坏动应力和最大动模量与初始含水量、干密度、静应力状态和动应力等各影响因素之间存在的、可以接受的规律性。它不仅表明了统计分析途径的发展前景，而且为通过统计建立黄土动力特性参数的经验关系提出了应该注意解决的主要问题和途径。 本文对不同地区黄土动力特性进行了较为系统的对比研究，提出了在大范围黄土动力特性研究中重视结构性的影响及用黄土潜在湿陷率这个概念反映黄土结构性的思路，建立了予估黄土破坏动应力与最大动模量的基本经验关系式。这些新的成果与见解具有一定的总结性，可以作为不同地区间黄土动力特性研究的一个良好开端。更多还原

【Abstract】 Based on analyzing and summarizing the previous study results of loess, inthis paper the dynamic characteristics of intact loess from three typical loessareas (Xi’an, Lanzhou and Taiyuan ) are compared and analyzed under thesupport of the opening laboratory of National Ministry of Geology and MineralResources. Some aspects such as the dynamic constitutive relationship, thedynamic modulus and the dynamic strength are investigated according to thedata obtained in dynamic triaxal tests under different moisture condition. Theeffect of moisture content and stress conditions to the damping ratio of Xi’anloess are also discussed. Further in order to find the relation between static anddynamic characteristics parameters and the possibility of evaluating dynamiccharacteristics only by using the common static characteristics parameters, thedynamic triaxal tests and common compression and collapse tests underdifferent moisture condition are performed and analyzed for the three typicalintact loess stated above. Lastly, the empirical relations of primary dynamicmodulus and dynamic failure stress with respect to various influence factors inthe same loess area are investigated based on the analyses and arrangement ofexisting loess dynamic characteristics data collected from various loess areas,The research results show that it is correct and essential to consider theeffect of dry density and especially of water content variation in researchingthe dynamic characteristics of loess of a certain loess area. But the effect of thedifferent loess structure characteristics must also be considered in that researchof different loess areas, besides the effect of dry density and water content. Theimportant role of structure characteristics is soaked in almost all the regularityof static and dynamic characteristic of Xi’an loess, Lanzhou loess and also ofTaiyuan loess. Accordingly, to instruduce the structure characteristics in theresearch of loess static and dynamic characteristic takes on the obviousessentiality and urgentlity. The concept of potential collapse rate that ispresented in this paper has its superiority and foreground in reflecting both the effect of structure characteristics of loess samples of a certain loess area duringthe process of compression deformation and the effect of different initialstructure characteristics of loess samples of various areas.In this paper, it is obtained through the careful analyze of different typicaltest data from dynamic triaxal tests and static compression and collapse tests,that the viewpoint to estimate the dynamic subsidence coefficient beforehandby using the static collapse coefficient has no special value both in theoreticaland in practical sense. Instead, the great attention should be paid to theconsideration of structure characteristics effect. This is the only key to developthe qualitative and quantitative characteristics as well as the parametervariations in researching the loess of a wide range.In this paper, the acceptable regularity existing in the loess primarydynamic modulus and dynamic failure stress with respect to the variousinfluence factors such as initial water content, dry density, static and dynamicstress state is obtained through the collection and arrangement of loessdynamic triaxal test outcome existed. It not only declares the foreground ofstatistical analysis method, but also presents the main problems and approachesthat should to be solved in order to establish the empirical relations among thedynamic characteristics parameters of loess.In surrunny the dynamic characteristics of loess at different area arecompared and stUdied systematically, a vieWPoint of considering the effect ofstructUre charaCteristics in stUdying the of dynamic characteristics of loess in alarge range and using the concept of rate of potential collapse to reflect thesmiCfor characteristics of loess are presented, and the basic empirical relationsfor更多还原