铁路路基改良土干湿循环耐久性试验研究

Experimental Study on Dry⁃wet Cycle Durability of Railway Subgrade Improved Soil

针对高等级高速铁路和特殊环境的建设中改良土耐久性要求严格的问题,通过调控水泥、石灰配比和级配,制作无膨胀性粉细砂和粉黏土、微膨胀性泥岩的改良土试件,测试试件每次干湿循环后的质量损失率和胀缩变化率。结果表明:粉细砂和粉黏土胀缩率不大于±0.2%;泥岩粒径在20 mm以下,水泥和石灰混合掺量在9%及以上时可以获得耐久性较好的改良土。

In view of the strict requirements for the durability of improved soil in the construction of high graded high speed railway and special environment,the improved soil specimens of non-expansive silty fine sand,silty clay and slightly expansive mudstone were made by adjusting the ratio and gradation of cement and lime,and the mass loss rate and expansion shrinkage change rate of the specimens after each dry-wet cycle were tested.The results show that the expansion and contraction rate of silty fine sand and silty clay is not more than±0.2%.The improved soil with good durability can be obtained when the particle size of mudstone is less than 20 mm and the mixed content of cement and lime is 9%or more.