宝兰客运专线路基刚柔性组合桩地基处理技术

依托宝兰客运专线路基的地基处理工程,研究深厚层强湿陷性黄土地基处理新技术。对刚柔性组合桩复合地基在湿陷性黄土地区的应用进行深入研究,首次提出了地基处理设计中工后沉降的计算方法。研究结果表明:在深厚层湿陷性黄土地基处理时,柔性短桩长度宜控制在5~10 m;当路基荷载超过200 kPa(路基填高超过8 m)时,应适当增加刚性桩的桩土应力比值,以提高刚性桩荷载分担比,充分发挥长桩的作用。宝兰客运专线自开通运营以来,刚柔性组合桩复合地基段路基状况良好,列车运行平稳。

Foundation Treatment Technology of Rigid Flexible Composite Pile in Baoji-Lanzhou Passenger Dedicated Line

Based on the foundation treatment project of Baoji-Lanzhou passenger dedicated line subgrade,the new technology of foundation treatment for deep layer and strong collapsible loess was studied in this paper.The application of rigid flexible composite pile foundation in collapsible loess area was deeply studied.The calculation method of postconstruction settlement in foundation treatment design was proposed for the first time.The results show that the length of flexible short pile should be controlled within 5~10 m when treating collapsible loess foundation in deep layer.When the subgrade load exceeds 200 kPa(the subgrade filling height exceeds 8 m),the pile-soil stress ratio of rigid piles should be appropriately increased to improve the load sharing ratio of rigid piles and give full play to the role of long piles.Since the opening and operation of Baoji-Lanzhou passenger dedicated line,the subgrade of rigid flexible composite pile foundation section is in good condition,and the train runs smoothly.