红黏土路基填筑压实度控制指标探讨

Discussion on the compaction degree index of subgrade filled with laterite

红黏土属于一类典型的特殊土,路基施工规范指出,特殊填料进行填筑路基时可根据具体情况适当降低压实度要求,并且规定有些高液限、高塑指黏土不能直接作为路基填料填筑。利用某高速公路处的红黏土进行了重型击实和承载比试验,试验结果表明:红黏土在最优含水率附近具有很强的水敏性。最优含水率点对应的CBR值并非最大值,其最大CBR值对应的含水率大于最优含水率3%左右,在此基础上结合土体的强度、压缩性、胀缩性、渗透性等指标随压实度变化的规律,确定该桩号红黏土作为下路堤填料其压实度可降低2.5%,填筑含水率控制在35%左右。

Laterite soil is one of the typical and special soil. There are clearly states in the technical specification of highway subgrades that the compaction degree can be reduced according to the specific condition when the subgrade constructs with special fillings. Moreover, the subgrade can＇t be filled directly with high liquid limit and high plastic index soils. By using the laterite of one highway, a series of compaction and California bearing ratio （CBR） tests are carried out; the results indicate that laterite is sensitive to water strongly; the water content corresponding to the maximum CBR is 3 % greater than the optimal one. In addition, according to the rules that strength, compressibility, swelling-shrinkage, permeability indexes change with compaction degree, the compaction degree of laterite which is as sub-embankment filling can be reduced by 2.5 %, the water content is around 35 % during compaction.