路基非饱和粉土的力学特性研究  

Study on Mechanical Characteristics of Unsaturated Silt in Subgrade

作　　者：何艾雨 唐博 HE Aiyu;TANG Bo(Southwest Municipal Engineering Design&Research Institute of China,Chengdu 610081,China)

机构地区：[1]中国市政工程西南设计研究总院有限公司,成都610081

出　　处：《路基工程》2022年第3期113-117,共5页Subgrade Engineering

摘　　要：利用重塑土样开展了土体的水土特征曲线试验和直剪试验,分析压实度、干密度、含水率及法向应力指标对非饱和粉土力学特性的影响规律。研究结果表明:非饱和粉土的水土特征曲线有典型滞后规律,尤其当土体压实度较低时,滞后规律更为显著;法向应力及含水率提升,非饱和粉土由早期剪切变形表现为软化,逐步转化表现为硬化特征,这一特征随土体干密度的提升而更加明显;随土体样本含水率提升,非饱和粉土黏聚力逐步下降,将这一规律进行线形拟合,整体拟合曲线表现为折线特征,且转折点与最佳含水率高度重合;含水率与内摩擦角间无明显相关影响规律,同等含水率水平下,土样干密度越大,内摩擦角也相对更大。The water-soil characteristic curve test and the direct shear test were carried out by use of remolded soil samples to analyze the laws how the indexes,including compaction degree,dry density,moisture content and normal stress,affect the mechanical properties of unsaturated silt.The result of the research shows that,the water-soil characteristic curve of unsaturated silt is of a typical hysteresis rule,especially when the soil compactness is low,the hysteresis is more significant;as the normal stress and moisture content increase,unsaturated silt has the shear deformation showing softening at the earlier stage,and then gradually changes to show hardening characteristics,which will be more obvious with the increase of dry density of soil;as the moisture content of soil sample increases,the cohesion of unsaturated silt decreases step by step and,if linear fitting is conducted on this rule,the fitting curve shows the characteristics of broken line with the turning point highly overlapping the optimal moisture content;there is not obvious related influencing rule between moisture content and internal friction angle and,under the same moisture content,the larger the dry density,the relative larger the internal friction angle.

关 键 词：路基 非饱和粉土 填料 直剪试验 水土特征曲线 

分 类 号：U414.1[交通运输工程—道路与铁道工程]