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通过采用粉喷桩复合地基处理工后沉降要求严格的高速铁路软土地基的现场试验,对粉喷桩复合地基处理软土地基的加固效果进行了系统的研究。试验表明,粉喷桩复合地基处理类似本试验段条件的高速铁路软土地基可以在较短工期内满足5 cm工后沉降的要求。无论是硬壳层还是淤泥质黏土层,粉喷桩复合地基的单位压缩值比塑料排水板排水固结法地基要小的多,黏土层的压缩模量得到了明显的提高。设置了碎石垫层后,粉喷桩桩体并无明显的向柔性基础刺入的现象发生,且垫层的设置达到了均化基底应力及调整差异沉降的目的。实测的孔隙水压力和沉降分析表明,与天然地基相比,粉喷桩复合地基的固结速率得到了较为明显的提高。位于地基不同位置的桩土应力比在不同时间不同荷载作用下是不同的,荷载稳定后的桩土应力比平均值为5.0。
By using the DJM pile composite foundation to deal with the strict requirements of post-construction settlement of high-speed railway soft soil foundation, the effect of soft soil foundation treatment by DJM pile composite foundation was systematically studied. The test shows that the high speed railway soft soil foundation treated by DJM composite foundation can meet the requirements of post-construction settlement of 5 cm in a relatively short period of time. The compressive modulus per unit area of the clay layer is much higher than that of the plastic drainage board consolidation method. After the gravel cushion is set, there is no obvious piercing phenomenon to the flexible foundation, and the cushion layer has the purpose of averaging the base stress and adjusting the differential settlement. The measured pore water pressure and settlement analysis show that compared with natural foundation, consolidation rate of DJM pile composite foundation is obviously improved. The pile-soil stress ratio at different positions of the foundation is different under different loads at different times, and the average stress-strain ratio of pile-soil after load stabilization is 5.0.