摘要
粉土路基强度受多因素制约,具有难碾压、易失水、水稳定性差等特点。为揭示各因素影响下不同初始状态的粉土强度变化规律,选取3种不同粉粒含量的粉土制备不同击实次数、不同含水率条件下的标准试件,分别进行浸水CBR试验和不浸水CBR试验。研究结果表明：随着初始含水率的增加,浸水CBR呈抛物线变化规律,不浸水CBR呈＂倒S＂变化规律;当初始含水率小于wopt＋1%时,增大击实功可有效提高浸水CBR值和不浸水CBR值,大于wopt＋1%时无明显影响;粉土试件浸水后,CBR衰减幅度受初始含水率影响较大,初始含水率小时衰减幅度最大,随着初始含水率的增大,CBR衰减幅度逐渐减小;初始含水率小于wopt＋1%时,粉粒含量越多,浸水CBR值越小,大于wopt＋1%时无明显影响;初始含水率在（wopt-1%,wopt＋1%）时,粉粒含量越多,不浸水CBR值越小,超出该范围后无明显影响;当初始含水率小于wopt＋1%时,浸水CBR与孔隙率Va具有良好的幂函数回归关系;含水率wopt＋1%可以作为粉土水稳定性、线膨胀率变化的分界点。
The strength of silt embankment is affected by many factors,with the features of being difficult to crush,easy to lose moisture,and poor water stability.In order to reveal the strength regularity of silt embankment under different initial conditions,three typical types of silt are selected.A series of laboratory experiments such as compaction tests,CBR tests are carried out under different initial conditions such as different compactness,different moisture,soaked CBR and non-soaked CBR.The study shows that with the increase of initial moisture content,soaked CBR shows parabola change rule,nonsoaked CBR presents a ＂S＂ change rule.When the initial moisture content is less than wopt＋1%,soaked CBR and non-soaked CBR are increased with the increase of compaction times.There is no obvious impact when the initial moisture content is more than wopt ＋1%.It is found that soaked CBR attenuation amplitude is significantly influenced by the initial moisture content.With the increase of initial moisture content,CBR attenuation amplitude is decreased.When the initial moisture content is less than wopt＋1%,soaked CBR increases with the increase of the silt content.There is no obvious impact when the initial moisture content is more than wopt＋1%.When the initial moisture content（wopt-1%,wopt＋1%）,the more silt content,the less non-soaked CBR.When the initial moisture content is less than wopt＋1%,soaking CBR and Va has a good power function relation between porosity.The moisture content of wopt＋1%can be used as the cut-off point of water stability and linear expansion rate.
作者
张燕明
刘怡林
ZHANG Yan-ming;LIU Yi-lin(The Communications Surveying Planning and Designing Institute of Shanxi Province,Taiyuan 030012;Research Institute of Highway,Ministry of Transport,Beijing 100088,China)
出处
《公路》
北大核心
2018年第11期253-259,共7页
Highway
基金
山西省交通建设科技项目,项目编号12-2-01
关键词
道路工程
强度特性
CBR试验
粉土
影响因素
road engineering
strength characteristics
CBR test
silt
influence factor
