基于黄土变形时效试验的高填方工后沉降研究

以填土厚约80 m的吕梁机场黄土高填方试验段为研究对象，开展不同性状黄土的室内变形时效性试验，并建立了反映其变形时效性的修正Burgers模型（M-B模型），将其引入到有限差分法软件FLAC3D中，开展了填土在不同压实度、含水率控制标准和不同地基处理方案下高填方的工后沉降规律敏感性分析。基于原位监测结果进行数值反演和预测分析，进一步探究室内试验得到的变形时效性参数与高填方概化层参数之间的差异。结果表明：深厚黄土地基上的高填方工程，其原地基的处理是控制工后总沉降的首要因素，在设计填料的压实度时，其含水率的控制也是影响工后沉降的重要因素；经反演分析得到，概化层变形参数比室内大1～4倍，预测得到深厚黄土地基上的高填方沉降稳定的时间需3～4 a，建议竣工后1.5～2.0 a开展基础设施建设。

Post-construction settlement analysis of loess-high filling based on time-dependent deformation experiments

The time-dependent deformation experiments on different types of loesses, which are sampled from the test section of loess-high filling 80 meters thick at Lüliang Airport, are carried out. A modified Burgers (M-B) model is established for depicting time-dependent behaviors of loess. The developed model is introduced to the software FLAC3D to analyze the sensitivity of post-construction settlement of loess-high filling due to such factors as compaction degree, control standard of water content and foundation treatment methods. Based on the in-situ monitoring data, the numerical back analysis and prediction are conducted to further study the difference between experiment parameters and generalized layer’s parameters of high filling. The results show that reinforcement treatment of original foundation is the first critical factor for controlling the post-construction settlement, and the water content selection is also important for designing the compaction degree of high filling. The generalized layer’s parameters of M-B model are one to four times bigger than the experiment ones. The stability duration time for post-construction settlement of the thick loess foundation needs 3 or 4 years. It is suggested that the construction of airport infrastructure should be carried out 1.5 or 2.0 years after the completion of the high filling.