黄河冲淤积平原区高速公路地基沉降规律研究

Research on subgrade deformation of powdery soil in alluvial plain of Yellow River

采用 FLAC 有限差分的计算方法建立了黄河冲淤积平原粉性土公路地基的流-固耦合模型。考虑孔隙水的排出过程和施工时路基的分层加载过程,对黄河冲淤积平原粉性土公路地基不同施工阶段的固结沉降进行了计算分析,并与现场实测的结果进行了对比。研究认为,对一般路段,当路基高度 H≤10 m 时,路基施工后可直接进行路面结构施工;当路基高度H≥12 m 时,放置6个月仍不能满足容许工后沉降的要求。对桥台与台背填土,这两个界限分别是路基高度 H≤6 m 和 H≥8m。对于涵洞、通道,分别是路基高度 H≤8m 和 H≥10m。

Using finite difference method,the fluid-mechanical interaction model is established with FLAC for powdery soil suhgrade of highway in alluvial plain of the Yellow River.Considering the process of discharge of the pore fluid and layered constructing in the actual roadbed construction,the process of the powdery subgrade deformation is analysed and compared with the result of fieldwork.The results show that,for ordinary section of a highway,the pavement structure can be directly constructed after the roadbed completed if the height of the roadbed≤10 m;and the allowable subgrade deformation after 6 months of pavement structure completed can not be satisfied if the height of the roadbed≥12 m.For the head of bridge,the two limits are≤ m and≥8 m of the height of roadbed respectively.For the culvert and channels,they are≤8 m and≥10 m respectively.