湿陷性黄土地基铁路路基工后沉降规律研究

摘要

Combined with test section for subgrade engineering in the first high standard railway with 160km/h--the second line of Lanzhou-Wuwei railway, the post-construction settlement discipline of loesssubgrade and treatment measures for collapsible loess ground are studied. Through contractive analysis of settlement-time forecasting models with settlement observed data, the suitable settlement forecasting model of loess subgrade, the chief settlement periods and the respective ratio of settlement of sugrade and ground in total settlement are provided. Through analysis of settlement observed data, it is obtained that the post-construction settlement of subgrade on collapsible loess ground treated with lime-soil compaction piles can meet the requirement of ballast track subgrade of high-speed railway, but can not meet the requirement of ballastless track subgrade of high-speed railway. When high-speed railway with ballastless track subgrade is constructed,the ground treatment must be strengthened,the cement-soil compaction pile,CFG pile,pile-board structure and pile-net structure can be selected according to collapsible loess ground.%结合2003年建设的西部黄土地区首条时速160 km的高标准铁路兰武二线路基试验段工程,对黄土路基工后沉降规律、湿陷性黄土地基的处理措施进行了研究.利用沉降观测数据进行沉降与时间预测模型对比分析,得出适合黄土路基工后沉降量预测模型,路基工后沉降量主要发生时间段,以及路基面沉降量中路基本体和地基沉降分别所占比例.通过工后沉降量实测数据分析发现,采用灰土挤密桩处理湿陷性黄土地基,工后沉降量能满足设计时速250～350 km高速铁路有砟轨道路基工后沉降要求,但不满足无砟轨道路基工后沉降要求；建设高速铁路无砟轨道路基时须加强地基处理,可根据湿陷性黄土地基情况选用水泥土挤密桩、CFG桩、桩板结构、桩网结构等.