改良膨胀土筑堤技术研究

利用改良膨胀土作为高速公路路堤填筑材料是宁淮高速公路需要解决的主要问题。尽管室内试验论证可以用石灰改良膨胀土性质，但现场石灰改良土施工还要解决三大问题：石灰拌和均匀性和石灰含量的检测问题、现场压实方法和压实度控制问题、现场压实改良土的胀缩性和强度是否满足高等级公路路床和路基的要求问题。结合宁淮高速公路先导段施工，设计了试验段进行现场试验。试验结果表明，通过合理的施工工艺、有力的质量控制，改良膨胀土能够满足设计要求。改良土已经不具有膨胀土性质，胀缩性低，CBR强度高，是良好的路堤填筑材料。

A study of construction of expressway embankment with modified soies

One of the key problems must be solved during the construction of the Ninghuai Expressway is how to use the modified expansive soils to construct the embankment. There are three main problems that should be solved for the proper use of the modified expansive soils: the first is how to mix lime into soil homogenously and how to detect lime contents; the second is how to compact the lime-modified soils effectively and what is the proper optimum Proctor density; the last is whether the characteristics of the filling of lime- modified soils is with satisfied the design requirement. Field tests have been conducted to require these questions. The results of the field tests show that the lime-modified soil has low swelling rate, low compression, and high strength if there is reasonable construction method and suitable quality controlled system.