石灰改良膨胀土填料试验研究

以改建铁路沪汉蓉通道襄樊至老河口段路基工程为依托，通过室内试验和现场检测试验，对石灰改良膨胀土的物理性质、胀缩性、强度特性、水稳定性和干湿循环下其强度变动规律进行了研究．研究结果表明：石灰改良土的塑性指数降低，胀缩性减弱；石灰改良土的抗剪强度与掺合比、养护龄期和压实系数均呈正相关性，石灰改良土最佳掺合比为5％～7％，60d龄期之后石灰改良土的抗剪强度基本趋于稳定；石灰改良土水稳定指标在0．70以上，具有很好的水稳定性；石灰改良土抗剪强度指标随干湿循环次数增加呈衰减趋势，但当干湿循环次数较大时，石灰改良土的粘聚力随循环次数的增加会出现一定程度的提高．现场压实质量检测结果表明，石灰改良土路基质量基本能满足规范要求．

Experimental Study of Improved Expansive Soil Filling with Lime

Based on the railway embankment engineering in a test section, the physical properties, impaction and swelling characteristics, intensity behaviors, water stability and intensity varying property with dry-wet cycling of lime-improved expansive soil are studied. The results show that plastic index and the impaction and swelling characteristics of lime-improved soil decrease ; the shear strength of lime-improved soil positive relates to the lime content, curing time and compaction coefficient, and it tends to stability after 60 days and the optimal lime content is 5% to 7%;the lime-improved expansive soil possesses favorable water stability and its water stability indexes are greater than 0. 7;the shear strength of lime-improved expansive soil decreases with times of dry-wet cycling, but with more times of dry-wet cycling, the cohension of lime-improved expansive soil will increase to an extent. The in-site detecting results of compaction quality show that the quality of embankment filled with lime-improved expansive soil meets the need of specification basically.