高速铁路泥岩地基原位减胀试验研究

以兰新高铁一处典型“弱”膨胀泥岩地基为例,通过现场原位变形监测试验,分别设计了不同减胀措施,研究了不同减胀措施（渗水孔、级配碎石层和重复荷载）与膨胀变形的关系.结果表明：9个消能孔（直径5 cm×深度110 cm）消能后基坑膨胀量分别是7个消能孔、5个消能孔膨胀量的0.42倍和0.26倍,即消能孔数量的增加可有效地消解膨胀泥岩的膨胀能;路基施工时可以采用多次碾压或堆卸载等重复加卸载的方式,也可以有效地消除路基的膨胀能;增设减胀层的方法施工相对简单易行且经济,可以有效地消减膨胀能,是避免膨胀变形量过大的实用工程措施.对变形量控制极为严格的高速铁路实际工程中,对膨胀土地基膨胀性应采取恰当的工程措施.

An In-situ Test of Expansion-Reducing Measures for Mudstone Foundation of High-Speed Railway

With a typical "weak" expansive mudstone foundation of Lanzhou-Xinjiang High-Speed Railway as an example, the relationship between expansion-reducing measures (water seepage hole, graded broken stone structure layer and repeated loading) and swelling deformation was studied in an in-situ deformation monitoring test. The results showed that expansive deformation in the treatments of 9 energy dissipation holes (5 cm in diameter and 110 cm in depth) was 42% and 26% of that in the treatments of 7 and 5 energy dissipation holes, respectively, indicating that energy dissipation porous holes could effectively reduce swelling deformation. The expansion energy of the roadbed could also be effectively eliminated by loading and unloading, multiple rolling compaction or heaping and unloading. In conclusion, the method of making a graded broken stone layer is simple and economical, so it is a practical measure to prevent or weaken the swelling deformation of expansive soil foundations, and appropriate measures should be taken so as to to meet the strict requirements of deformation for high-speed railways.