高铁路基下长短桩处理的湿陷性黄土地基沉降分析

Settlement analysis for long-short-pile composite foundation in collapsible loess area under high-speed railway subgrade

以某高速铁路客运专线湿陷性黄土路基试验工程为依托,进行了沉降变形观测和路基沉降预测,研究了高速铁路技术条件下长短桩复合地基的沉降变形特性和沉降控制效果。结果表明,地基压缩沉降是路堤沉降的主要组成部分,地基的沉降主要体现在地基处理深度以下的下卧土层的沉降上。采用双曲线法、三点法和Asaoka法曲线拟合法预测路堤的最终沉降量是合理的,剩余沉降量满足铺设无砟轨道对路基工后沉降的控制要求,采用CFG桩+柱锤冲扩桩的长短桩复合地基是一种合理、有效的沉降控制方法。

This paper presents an example of a passenger dedicated line constructed on the collapsible loess subgrade. The subgrade settlement deformation was measured and predicted. The settlement deformation characteristics with long-short-pile composite foundation under high-speed railway technology conditions were analyzed. The measured data show that the foundation settlement which mainly takes place in substratum under foundation treatment depth is dominated component of subgrade settlement. Subgrade final settlement can be reasonably predicted with a hyperbolic method, three-point method and Asaoka method. Residual settlement meets the requirements of controlling subgrade settlement for laying unballasted track after construction. It is recommended to adopt long-short-pile composite foundation as the foundation treatment method for collapsible loess ground.