含水率和密度对伊犁黄土湿陷系数的影响  

Effect of moisture content and density on collapsibility coefficient of Ili loess

作　　者：张婉[1] 张爱军[1] 陈佳玫[1] 刘毅[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《西北农林科技大学学报（自然科学版）》2017年第5期211-220,共10页Journal of Northwest A&F University(Natural Science Edition)

基　　金：国家自然科学基金项目(51279171)

摘　　要：【目的】研究不同干密度和含水率对伊犁黄土湿陷性的影响,为类似黄土区填土工程设计提供试验数据。【方法】以伊犁黄土为研究对象,利用YS-I高压固结仪对5种含水率(6.6%,12.5%,14.1%,18.2%,21.0%)和5种干密度(1.24,1.31,1.39,1.47,1.55g/cm^3)的黄土试样进行完全正交湿陷试验,选用双线法测定不同含水率和干密度下黄土的湿陷系数,研究压缩变形和湿陷变形占总变形的比例以及湿陷系数的变化,并与西安、兰州地区黄土的湿陷性进行比较。【结果】在干密度相同的条件下,伊犁黄土压缩变形占总变形的比例随着压力增大表现出的变化趋势不尽相同,在高压力(400kPa以上)时逐渐增大,是变形的主导因素;在低含水率(6.6%)和低压力(200kPa以下)条件下,湿陷系数随着干密度的增加而减小,但在高含水率和高压力条件下,湿陷系数随着干密度的增加呈现出先减小后增大再减小的趋势。随着含水率的增加,湿陷变形占总变形的比例逐渐降低,湿陷系数的敏感性降低;当干密度大于1.47g/cm^3且上覆压力小于100kPa时,可认为该黄土几乎不发生湿陷。与西安、兰州地区黄土相比,伊犁地区黄土的湿陷性更强。【结论】含水率和干密度对伊犁黄土的湿陷系数具有大的影响,在填筑时尽量提高其压实度,以减弱黄土的湿陷性。[Objective] The influence of different dry densities and moisture contents on collapsibility of Ill loess was studied to provide experimental data for filling construction in loess area. [Method] The doub- le-line collapsibility test was conducted with YS-I high pressure odometer to determine the collapsibility co- efficient of Ill loess with 5 different moisture contents （6.6%,12.5%,14.1%,18.2% ,and 21.0%） and 5 dry densities （1.24,1.31,1.39,1.47, and 1.55 g/cm3）. The changes in ratios of compression deformation and collapsibility deformation in total deformation as well as the collapsibility coefficient were studied, and comparison was made between Ili, Xi＇ an and Lanzhou loess. [Result] Under same dry density condition, the variation trend of ratio of compression deformation in total deformation of Ili loess was different with the increasing pressure. Above high pressure （400 kPa）, the proportion was gradually increasing, and compres- sion deformation was the dominant factor. Under low moisture content （6. 6%） and low pressure （200kPa）, the collapsibility coefficient declined with the increase of dry density. While under high moisture con- tent and pressure, the collapsibility coefficient reduced first and then raised before reducing again with the increasing dry density. The proportion of collapsibility deformation in total deformation gradually decreased with the increase of water content, and the sensibility of collapsibility coefficient declined. When the dry density was more than 1.47 g/cm3 and overlying pressure was less than 100 kPa,it can be considered that the loess almost had no collapsibility. Compared with Xi＇ an and Lanzhou loess, the collapsibility of Ili loess was stronger. [Conclusion] The influence of moisture content and density on collapsibility coefficient of Ili loess was strong. When being used as filled soil, the compaction degree of the loess need to be improved in order to weaken the collapsibility.

关 键 词：伊犁黄土 湿陷变形 湿陷系数 土壤含水率 土壤干密度 

分 类 号：TU411[建筑科学—岩土工程]