湘西南红黏土路堤填筑技术研究

Study of embankment filled technology of laterite soil in Southwest Hunan

湖南的湘西南地区气候潮湿多雨,由于特殊的气候及地质条件,广泛分布着由碳酸岩风化形成的高液限红黏土。红黏土天然含水率高,又由于其本身固有的大孔隙比和结构性强的特点,要达到规范要求的压实度较为困难。结合该地区公路建设,开展了红黏土填料含水率、松铺厚度、碾压机械等多种工况组合下的现场碾压试验研究,其目的在于探求适合红黏土填料的碾压工艺,提出兼顾土体碾压效果和路堤填筑质量的压实控制建议。研究表明,压路机选用凸块振动碾、填土松铺层厚度控制在25～30 cm、土体含水率控制在大于最优击实含水率2%～5%范围时,现场碾压效果较好,压实土体也将具有较为稳定的工程性质。

It exists high liquid limit of laterite soil abundantly in southwest area of Hunan Province, which weathered from carbonate rocks due to the humid and rainy climate and geological conditions. The laterite soil possesses special features, such as high natural moisture, inherent large void ratio, strong structural features; so it is difficult to meet the normative requirements of compaction degree. In order to discuss the appropriate compaction technology and put forward an embankment compaction control recommendation for laterite soil, field tests are carried out which combined with many different conditions such as moisture, loose laying depth, rolling machines and so on. The results show that the compacted effect is better when using bumping vibration rolling, controlling the laterite soil filling with 25-30 cm loosing thickness and water content beyond the optimum moisture content 2%-5%. At the same time, the comoacted soil will have more stable engineering characteristics.