冲击碾压工艺在路基施工中的应用探讨

Discussion on the Application of Impact Rolling Technology in Subgrade Construction

黄土路基结构松软、孔隙率大,存在的湿陷性特征易造成路基结构失稳。以我国西南部某道路工程实例为对象,针对黄土路基特殊的结构特征,确定在填方路基两边10 m范围采用振动压实,在挖方区采用冲击碾压的工程施工方案。分析了该方案下冲击碾压对路基的性能影响,获得最优压实遍数的机械组合形式。研究结果表明:随着碾压遍数增加,土层孔隙率逐渐减小,压缩模量不断提高。土层越深,冲击碾压对下部土体孔隙和压缩模量的改善作用逐渐降低。在进行12遍重复冲击压实前,土体累积沉降量随压实遍数的增加改善效果显著,当碾压遍数达到40次后,压实遍数土体沉降量的影响作用可以忽略。

The instability of loess subgrade structure is caused by soft structure, strong compressibility and large porosity, which is easy to cause collapsibility. In this paper, an example of a road project in southwest China is taken as the object, according to the special structural characteristics of loess subgrade, the form speed of impact road press is set at 12 km/h, the vibration compaction is adopted in the range of 10 m on both sides of the fill subgrade, and the engineering construction scheme of impact compaction is adopted in the excavation area. The change of performance parameters of subgrade under the action of impact compaction technology is analyzed, and the mechanical combination form of optimal compaction number is obtained. The results show that with the increase of rolling times, the porosity of soil layer is good for collapsibility. The compression modulus increases with the decrease of compression modulus. The deeper the soil layer is, the smaller the pore change of the lower soil is, the less the collapsibility is eliminated, and the faster the compression modulus is. The cumulative settlement of soil increased significantly before 12 times compaction. When the number of compaction times reached 40 times, the compaction degree of 150 cm soil could be kept above 85%, which could be determined that the effective depth of impact compaction was within the range of 150 cm.