黄土的结构屈服及湿陷变形的分析

发布时间：2018-01-15 22:31

本文关键词：黄土的结构屈服及湿陷变形的分析　出处：《岩土工程学报》2017年08期 　论文类型：期刊论文

【摘要】：黄土是一种典型的结构性土,其湿陷性是浸水后黄土结构破坏的反应。黄土的结构性可用构度指标定量地描述,它既包含了土的物质组成,还包含了不同沉积年代黄土的结构特征。加载和浸水均可引起黄土结构性衰减,加载结构性衰减可由一定含水率黄土的压缩结构屈服应力和压缩变形曲线表征;浸水结构性衰减可由浸水的压缩结构屈服应力减小和压缩变形曲线的变化表征。针对不同场地、不同沉积年代的Q_3黄土和Q_2黄土,依据不同含水率黄土的压缩曲线,分析了不同黄土构度指标与其压缩结构屈服应力之间的关系,以及黄土压缩变形过程中孔隙比和初始孔隙比比值与压缩应力和压缩结构屈服应力比值对数之间的关系。表明不同沉积年代黄土的构度随其反映基本物性的综合物理特征量单调变化,压缩结构屈服应力与构度之间近似呈线性关系,压缩结构屈服前后的孔隙比比值和压缩应力比值对数之间服从近似一致的变化规律。建立了由黄土沉积年代和基本物性指标确定构度,进而确定压缩结构屈服应力;依据孔隙比比值与压缩应力比比值对数的关系,分别描述天然含水率黄土和浸水饱和黄土的压缩曲线;进而,确定饱和自重作用下黄土的自重湿陷系数,计算场地自重湿陷变形的评价方法。该方法应用于西安地区黄土场地自重湿陷评价,得到了与现场浸水试坑试验实测自重湿陷量比较一致的结果,论证了考虑黄土结构性的湿陷性评价方法的合理性和准确性,为建筑黄土地基湿陷变形和大厚度湿陷性黄土地下结构地基湿陷变形评价提供了一种新途径。
[Abstract]:Loess is a kind of typical structural soil, the collapsible loess structure is destroyed after immersion reaction. Available structural structural index of quantitative description of loess, it includes the soil material composition, structure characteristics of loess in different sedimentary age also included. Loading and immersion can cause the structural damping, structural load by the attenuation of moisture in loess compression structure yield stress and compressive deformation curves; structural water attenuation can be soaked by the compression structure variation of yield stress decreases and the characterization of compression deformation curve. According to the different field, different deposition in the Q_3 and Q_2 structural loess, loess according to different water content compression curve analysis of different loess structural index and compression yield structure of the relationship between stresses and loess compression deformation in the void ratio and initial void ratio and the ratio of compressive stress The structure and compression yield stress between the logarithm of the structure with different degrees. The results indicated that sediments in Loess reflect the physical characteristics of the basic properties of the content monotonously, compression structure yield stress and structure between the approximate linear relationship before and after the structure yields the void ratio of compression ratio and compression stress ratio obey logarithmic approximation the same variation was established. The degree is determined by the loess's and basic properties, and then determine the compression yield stress; on the basis of void ratio and compression ratio of the stress ratio between the logarithm of the compression curve respectively describe the natural water content of loess and saturated loess; and then, determine the saturation under gravity loess collapsibility coefficient, evaluation method of calculation of collapsibility deformation. This method is applied to the area of Xi'an loess collapsibility evaluation, obtained and field leaching Water test pit test of collapsibility relatively consistent results, demonstrates the collapsibility of loess considering structural evaluation method of rationality and validity, for the construction of loess foundation deformation and the thickness of wet and provide a new way of collapsible loess foundation collapsibility evaluation of underground structures.

【作者单位】：西安理工大学岩土工程研究所;陕西省黄土力学与工程重点实验室;
【基金】：国家自然科学基金项目(41272320,11572245)
【分类号】：TU444
【正文快照】： linear relation with structural index.The compression curves ofnatural loess and saturated loess can be respectively describedin accordance with the logarithmic relationship between the ratio of pore ratio and the ratio of compressive stress,thereby,thec

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