高速公路膨胀土路堤处治后期土体性状试验验证

Expansive soil character later test verification on freeway embankment treatment

为了解膨胀土路基改性填筑后的土体性状,加深对膨胀土改性处治的认识,对某高速公路膨胀土路基改性处治 1 年多以后的土体性状进行了后期试验验证。结果表明:膨胀土路基后期含水量和干密度均有不同程度的变化,变化规律与处治方式、钻孔位置和取样深度密切相关。膨胀土直接用于路基填筑,后期干密度有所降低,将对路基长期稳定性造成不利的影响;石灰改性后填筑后期干密度的增加,有利于路基的长期稳定;煤粉灰改性在一定程度上改善了膨胀土性能,但处治效果不如石灰,隐患尚未彻底消除。

In the expansive soil area freeway embankment construction the expansive soil needs treatments if not take the displacement and refilling measures. This is especially necessary in the middle and strong expansive soils building foundations. In order to find out the status after the expansive soil embankment modified treatment and deepen the comprehension of the treatment effect, we carried out the experiment about the expansive soil characteristic on freeway embankment construction one year later. Results show that the later moisture content and dry density change in different degree which is related to the treatment mode, boring position and sampling depth. Later dry density will reduction which will induce to safety incipient fault. If embankment fulling up with full expansive soil, the later dry density will increase and the long-term stability will be safeguard with lime modified expansive soil. Flyash improves the capability of the expansive soils in a certain extent, but the effect is not as good as the lime and the incipient fault hasn't been eliminated thoroughly.