组合双曲线法在高铁路基沉降预测中的应用

Application on Combined Hyperbola Method for Predicting Settlement of High-speed Railway Subgrade

高速铁路路堤普遍采用堆载土预压的施工方法加速路基的固结沉降。由于预压土荷载的快速施加,路基沉降曲线在填筑期与预压期之间常出现较为明显的变化。本文在总结和分析三点法、双曲线、指数曲线、泊松曲线、经验系数矫正法等路基沉降预测模型特点和适用性的基础上,基于传统双曲线沉降预测模型,提出一种适用于堆载预压工况下的高铁路基沉降预测方法——组合双曲线法。组合双曲线沉降预测模型考虑了堆载预压后沉降速率突然变大,将模型方程按照路基本体填筑期和堆载预压期分为两个阶段,分别进行参数确定。将组合双曲线沉降预测模型应用于京沈高铁某路基段,并与其他传统沉降预测模型计算结果进行对比,验证了组合双曲线法的适用性。

Preloading method is a typical procedure for accelerated sedimentation on soft ground of high-speed railways. Due to the rapid application of preloading, the subgrade settlement curve often showed a greater shape variation between roadbed construction stage and piling-up preloading stage. The characteristics and applicability of three-point method, hyperbola, exponential curve, Poisson curve and empirical coefficient correction settlement prediction model were summarized. Based on the traditional hyperbolic settlement prediction model, the combined hyperbola method for high-speed railway subgrade under surcharge preloading was proposed. The method considers the sudden increase of settlement rate after preloading, and divides the equation into two stages to determine the parameters respectively. The applicability of the combined hyperbolic method is verified by comparing it with other models through an engineering example in a subgrade section of Beijing-Shenyang High-speed Railway.