新建合宁铁路改良膨胀土填筑路基沉降规律研究

结合合（合肥）宁（南京）客运专线改良膨胀土填筑路基试验段,根据膨胀土地基上填筑路基的不同基底处理方式、不同边坡防护形式来设置观测断面,通过埋设沉降板、路基边坡变形观测桩,对路基沉降及变形进行观测,研究膨胀土地基的沉降变形、主要影响因素及改良膨胀土路基的变形规律,预测工后沉降。通过对比分析,发现改良膨胀土填筑路基成型初期沉降受载荷以及天气影响明显,随着时间的推移,变形逐渐趋于稳定,路基成型后期受天气影响不显著,路基表现稳定。说明石灰改良膨胀土具有良好的工程性质,改良灰土填筑路基具有良好的水稳定性和抗变形能力,从而为全线设计施工提供了依据。

On Settlement and Deformation Law of Roadbed Filled with Improved Expansive Soil in the Newly-built Hefei-Nanjing Railway

Based on the test plot of roadbed filled with improved expansive soil in Hefei-Nanjing PDL,observation section is set according to different foundation treatment and slope protection forms of filling roadbed on the expansive foundation. Through burying settlement plates and observation piles for roadbed slope deformation,roadbed settlement and deformation are observed.Settlement deformation and main influencing factors of expansive soil foundation are studied,deformation laws of improved expansive soil roadbed are got,and settlement after engineering is predicted.Through comparison and analysis, it is found that settlement of roadbed filled with improved expansive soil is significantly affected by the load and weather at the initial formation stage.As time goes by,its deformation trend gets stable,and the roadbed is immune to weather at the later formation stage in a stable state.These prove that lime-improved expansive soil has a good engineering property, and the roadbed filled with improved lime soil has a good water stability and anti-deformation ability,which provides bases for design and construction of the whole line.