黄泛区非饱和粉土压缩模量和有效应力参数的探讨  

Research on compression modulus and effective stress parameter of unsaturated silt in the Yellow River flood area

作　　者：徐安全[1] 岳建伟[1] 宋达[1] 杨光辉[1] 

机构地区：[1]河南大学土木建筑学院,开封475000

出　　处：《应用力学学报》2017年第4期672-678,共7页Chinese Journal of Applied Mechanics

摘　　要：基于多孔介质中各组分对荷载的分担能力与其自身压缩特性相关联的思路,通过不同孔隙率土体的天然重度、含水率之间的公式转换,提出了由K_n到K_(S_rn)的转换系数法,进而可计算有效应力参数值。通过系列室内侧限压缩试验,研究了压缩模量的变化规律,并利用MATLAB三维拟合得出压缩模量的表达式,该表达式以土体的基本试验指标(天然重度γ、土粒密度ρ_s、含水率w)为自变量,更便于直观表现压缩模量的变化规律。在土体有效应力表达式的基础上,利用不同钻孔点、不同深度粉土层的基本试验数据,得到了黄泛区非饱和粉土有效应力参数χ的值。结果表明:与文献中黄土的χ值相比,当饱和度低于70%时,黄泛区粉土的χ值约为黄土的1.27倍~1.5倍;当饱和度高于85%时,黄泛区粉土与黄土的χ值趋于一致,此时非饱和土的有效应力表达式开始向饱和土的有效应力表达式的形式过渡。A method of coefficient conversion is put forwarded to calculate K_(s_rn) with K_n based on the research approach that the sharing load of each component is related to its compression performance. The varying law of compression modulus of unsaturated silt in the Yellow River flood area is studied by series of indoor compression tests. The expression of compression modulus is fitted by MATLAB taking the primary test indicators(natural unit weight, density and water content) as independent variable and it is more intuitional to study the varying law of compression modulus. On the basis of effective stress expression, a series of proposed values of effective stress parameter in the Yellow River flood area is put forwarded according to the basic test data of different silt layers as references for engineering application. Compared with Chen Zhenghan's research, effective stress parameter value of silt in the Yellow River flood area is 1.27 to 1.5 times as much as that of loess when the saturability is lower than 70%. Nevertheless, effective stress parameter values of silt and loess are tend to be more consistent when the saturability is higher than 85%, and the form of effective stress expression begin to change from unsaturated state to saturated state.

关 键 词：黄泛区非饱和粉土 压缩试验 压缩模量 有效应力参数 

分 类 号：TU431[建筑科学—岩土工程]