基于强度分区的膨胀土路堤稳定性及土工格栅处治效果分析

由于填筑密实度、含水率的差异，整个膨胀土路堤内存在以含水率和干密度为特征的强度分区，且路堤表层土体由于直接受大气、降雨作用，温度、湿度变化频繁，胀缩变形剧烈，裂隙发育，强度将剧烈衰减。但该实际存在的强度分区一般在稳定性计算中多被简化为均质体而不能反映实际情况。强度分区法则考虑大气和气候影响以及路堤内压实度差异，并综合考虑土工格栅的作用。基于强度分区的膨胀土路基边坡稳定性的分析结果表明，强度分区法更能反映路堤土体强度差异的实际情况，能真实地体现改性处治和铺设土工格栅对路堤稳定的贡献，具有显著的优点。对于素填土膨胀土路堤，边坡表层容易发生局部浅层滑动，进而诱发和牵引发生深部滑动破坏；石灰改性后虽能提高路堤稳定性，但表层局部稳定性安全储备并不宽裕，尚未彻底根除安全隐患。土工格栅虽对整体稳定性贡献不大，但可显著提高局部稳定性，并有效地消除膨胀土路堤边坡浅表滑塌的隐患。

Expansive soil embankment stability and geogrid treatment effect analysis with strength zoning method

In the whole expansive soil embankment,there exist different strength zones due to different water content and dry densitiy caused by the construction course,atmosphere and rainfall.Soil strength in the surface zones usually be strongly attenuated by the alternately wetting and drying,expanding and shrinking.But this condition usually is ignored in the embankment stability analysis.Strength zoning method takes the climate and weather into consideration.Based on the strength zoning method,expansive soil embankment stability and geogrid treatment effect analysis results show that the expansive soil embankment will easily slide in superficial layer if the embankment is constructed by full expansive soils.Stability will increase if the embankment be constructed by lime modified expansive soil,but the emergency capecity is insufficient and the incipient fault is also existence.Superficial stability will increase evidently while the resistance to overturning only increase a little if embankment being treated by geogrid,incipient fault has been effectually reduced or eradicated.All of these show the superiority of the strength zoning method for expansive soil embankment stability analysis.