膨胀土石灰改良路基填筑工艺与质量控制试验研究

某新建铁路运煤通道工程湖北段，膨胀土分布广泛，路基工程若采用远运合格填料直接填筑方案，工程费用昂贵，为保护环境、减少膨胀土弃方，以试验工点为依托结合室内改良土配合比试验、填筑工艺试验、质量检验等方法对膨胀土掺入石灰改良后作为路基填料展开了系统研究。结果表明:膨胀土掺入3.5%，5.0%的石灰改良后，土体力学强度及水稳定性明显提高，颗粒组成及胀缩特性大幅降低，可达到合格填料要求。采用的集中场地路拌法及相应的填筑工艺，填筑质量可满足规范要求。

Experimental Study on the Filling Process and Quality Control for Expansive Soil Lime Improved Subgrade

The construction site of building new channel of transporting coals on railway is located in Hubei province where expansive soil is widely distributed. If the "long haul transport qualified and direct filler" scheme is adopted in the subgrade project, the cost of construction would be rather high. With the purpose of reducing the discard of expansive soil and environment protection, the paper systematically expounds the application of expansive soil as subgrade filler improved by mixing lime, based on test worksite, combining with the methods of indoor improved soil mix proportion test, filling process test and quality inspection, etc. The results show that adding 3.5%, 5.0% lime into expansive soil for improvement would visibly increase the mechanical strength of soil and water stability. Moreover, soil particle size, expansion and shrinkage characteristics are reduced significantly, meeting the requirement of qualified filler. By adopting of centralized premixing road-mixing method corresponding filling method, the filling quality could meet the specifications.