高速公路在路基修筑中会经常遇到大量的软弱土层,它的物理力学指标、工程性质、路基稳定性均比软土要好,但沉降变形不能满足设计要求,为此,必须专门处理。尤其对厚度较大的湿陷性黄土地基,用夯扩挤密桩处理非常有效。它是利用锤击成孔等方法在土中形成桩孔,然后分层回填灰土夯实而成。在成孔和夯实过程中,原处于桩孔部位的土体挤入周围土体中,使桩周一定范围内的土体被挤密而达到有效提 Expressway will often encounter a large number of weak soil in subgrade construction. Its physical and mechanical indexes, engineering properties and roadbed stability are better than those of soft soil. However, settlement deformation can not meet the design requirements. Therefore, it must be specially dealt with. Especially for thick collapsible loess foundation, it is very effective to treat with compaction piles. It is the use of hammering into holes and other methods in the formation of pile holes in the soil, and then layered backfill ash compacted. In the process of forming holes and tamping, the original soil at the site of the pile hole is squeezed into the surrounding soil so that the soil within a certain range of the pile circumference is squeezed to be effective