非饱和土地区高速铁路路基沉降预测模型

准确、合理地预测线路工后沉降是高速铁路建设的关键,现场沉降观测数据表明不同饱和度地区路基沉降曲线线型变化较大,基于饱和理论的沉降预测方法在工后沉降预测中存在不能准确描述沉降规律,且存在预测值偏小的风险。基于实测沉降规律,提出了一个适用于非饱和土地区路基的沉降预测曲线模型。分析了预测曲线模型的特点,并基于最小二乘法给出模型参数的求解方法。结合兰新铁路第二双线LXS-15标段沉降数据,提出相关系数、偏差度、稳定度为模型有效性检验指标,结合施工完成2 a的实测资料,进行了在施工完成3个月及6个月所提模型与规范要求3种预测模型的对比研究;对3条不同饱和程度高铁路基沉降预测结果表明所提出的非饱和土预测模型具有较好的精度和广泛的适用性,为非饱和土地区高速铁路建设合理判断工后沉降提供参考。

Prediction model for settlement of high-speed railway embankment in unsaturated areas

The precise prediction of post-construction settlement for high-speed railways is one of the key techniques in successful construction of high-speed railways. The in-situ observation data show that the shapes of settlement vary greatly under different unsaturated conditions. Limitations and risks are observed to predict unsaturated settlement using the traditional predication methods based on the saturated theory. A new prediction method for post-construction settlement of unsaturated high-speed railway embankment is proposed. The characteristics of the proposed model are analyzed, and the solving algorithm for the model is developed. Based on the observed settlement data in LXS-15 of Lanzhou-Xinjiang Double-Line Railway, predictions are carried out respectively using the proposed model and other three methods. By defining the correlation coefficient, deviation degree and stability property as the evaluation indices and using 2 years' continuous in-situ observation data, the prediction precision is investigated and compared. The applications in three sections with different saturations show that the proposed settlement prediction model is feasible and scientific for unsaturated embankment of high-speed railways, and it may provide a method for prediction of post-construction settlement of high-speed railways in unsaturated areas.