浅埋式桩板结构在宝兰客运专线湿陷性黄土短路基中的应用研究

摘要

我国西北地区广布冲、洪、风积黄土，地质情况非常复杂，宝兰客运专线山区深厚层湿陷性黄土具有高压缩性、湿陷等级高、遇水易产生湿陷等特点，路基工后沉降值要求严格，路基、桥梁、隧道频繁过渡，各结构物的刚度及工后沉降均存在差异，影响无砟轨道的刚度和变形均匀性。针对以上难题，结合宝兰客运专线深厚层湿陷性黄土采用浅埋式桩板结构处理措施进行分析研究，其既能满足路基工后沉降要求，又能有效地减少各结构物工后沉降差异值。%In northwest China, the geological condition is so complicated that there are widespread alluvial, diluvial and aeolian loess. And in its mountain area where the Baoji-Lanzhou Railway passenger dedicated line passes through, the deep and thick stratum of collapsible loess is characterized by high compressibility, high collapsibility, easy to collapse when meeting water, and so on. Still more, the requirement stipulated in technical code about subgrade post-construction settlement is very strict, while there are frequent transitions among subgrades and bridges and tunnels, forming stiffness differences and post-construction settlement differences among them, and then inevitably affecting the stiffness uniformity and deformation uniformity of the ballastless track. This paper, focusing on the problems above, and in combination with the project of Baoji -Lanzhou Railway passenger dedicated line, analyzed and In northwest China, the geological condition is so complicated that there are widespread alluvial, diluvial and aeolian loess. And in its mountain area where the Baoji-Lanzhou Railway passenger dedicated line passes through, the deep and thick stratum of collapsible loess is characterized by high compressibility, high collapsibility, easy to collapse when meeting water, and so on. Still more, the requirement stipulated in technical code about subgrade post-construction settlement is very strict, while there are frequent transitions among subgrades and bridges and tunnels, forming stiffness differences and post-construction settlement differences among them, and then inevitably affecting the stiffness uniformity and deformation uniformity of the ballastless track. This paper, focusing on the problems above, and in combination with the project of Baoji -Lanzhou Railway passenger dedicated line, analyzed and researched the treatment measure for the deep and thick collapsible loess by the use of shallowly-buried sheet-pile structure, with the result that this sheet-pile structure not only was able to meet the requirement on subgrade post-construction settlement but also was able to effectively reduce post-construction settlement differences among the different structures.