湿度和密度变化下伊犁黄土的压缩和湿陷特性

Characteristics of compressibility and collapsibility of Ili loess under varying water content and dry density

为揭示西风区伊犁黄土的变形特性,利用YS-I高压固结仪,开展了不同干密度和含水率下的双线法湿陷试验,探究了伊犁黄土的压缩特性和湿陷特性。研究结果表明:含水率越大、干密度越小,压缩屈服应力越小,压缩系数a1-2越大,δs-p曲线的软化性越强;湿陷系数与含水率、干密度均近似呈线性负相关;当干密度大于1.6 g/cm3时,伊犁黄土的湿陷性基本消失;可采用e/e0-lg(p/pc)的指数关系表征不同含水率下的归一化压缩曲线,并提出了考虑干密度影响的表达式;针对典型的湿陷曲线提出了一个能较好反映湿陷变形曲线软化特征的4参数模型,并给出了考虑干密度和含水率的模型公式,为中亚西风区黄土地区的工程建设提供借鉴。

To reveal the deformation characteristics of the Ili loess in westerly wind regions,we conduct laboratory tests on its collapsibility with different dry densities and water contents using the double line method and a YS-I high-pressure consolidation apparatus,focusing on the characteristics of its compressibility and collapsibility.Results show that higher water content or smaller dry density leads to smaller yield stress,larger compression coefficient a1-2,and stronger softening on theδs-p curve.And collapsibility coefficient has negative linear correlation with water content or dry density,and it diminishes to nearly zero when the dry density is bigger than 1.6 g/cm3.We derive an expression of compressibility with the parameter of dry density and reveal that under different water contents,the normalized compressibility curve can be characterized using an exponential relationship of e/e0 versus lg(p/pc).For typical collapsible curves,we construct a four-parameter model that better reflects the softening characteristics of collapsible deformation curves,and present a normalized model formula including the parameters of dry density and water content.This work may be helpful to engineering construction in the westerly wind loess region of Central Asia.