不同地基处理方法对加宽培厚堤防差异沉降控制效果研究

Research on the Differential Settlement Control of Heightened and Widened Embankment under Different Foundation Treatments

为提高堤防的防洪能力,对已建堤防进行加宽培厚是一种常见的加固方式。堤防加宽培厚工程中新老堤防的差异沉降易引起堤身开裂等问题,因此常常需要对加宽培厚堤防的差异沉降进行控制。以深厚淤泥地基上的堤防工程为例,建立相应的有限元模型,软土层采用了修正剑桥模型,分析加宽培厚堤防的变形特性以及不同地基处理方法对堤防差异沉降的控制效果。结果表明:当不采取地基处理措施时,新堤堤顶的最大差异沉降达到34 cm,堤顶倾度为3.8%;堤防加宽培厚工程的最佳地基处理区域位于加培新堤下方;桩体复合地基和排水固结法均可减小堤顶的差异沉降,但桩体复合地基对差异沉降的控制效果更加明显;采用桩体复合地基时,最大差异沉降减少至9.2 cm,堤顶倾度为1.4%。

To improve the flood protection capacity of embankments, heightening and widening the constructed embankment is a common method of embankment reinforcement. The differential settlement of old and new embankment in embankment expansion projects is likely to cause problems such as embankment cracks,so it is often necessary to control the differential settlement of heightened and widened embankments. By taking the embankment project on deep silt foundation as an example,the corresponding finite element model was established,and the modified Cam-clay model was adopted for the soft soil layer. The deformation characteristics of the heightened and widened embankment were analyzed, as well as the effect of different foundation treatments on the differential settlement control. Results show that the maximum differential settlement at the top of the new embankment reaches 34 cm and the inclination of the top of the embankment is 3. 8% without foundation treatments;for the embankment heightening and widening project, the best foundation treatment area is located below the new embankment;both pile composite foundation and drainage consolidation method can reduce the differential settlement of embankment, but the pile composite foundation is more effective in controlling the differential settlement. The maximum differential settlement was reduced to 9. 2 cm and the inclination of the embankment top was 1. 4% when the pile composite foundation was used.