气泡混合轻质土在陕北淤地坝地基台背回填中的应用研究

在延安至延川高速公路淤地坝地质条件下选择试验段，开展高填方台背回填用气泡混合轻质土的设计、施工和质量控制，并对其力学性能、土压力（侧压力）大小以及路基沉降量进行监测。结果表明:淤地坝地基（地基承载力仅为100 kPa）可直接采用气泡混合轻质土进行台背回填，对原有地基只需进行简单的整平和碾压处理，其强度及变形能力均能满足使用要求，且现场监测结果发现台背所受侧压力最终都有趋于零的趋势，路基和地基均未出现显著沉降，可减少桥头跳车病害。

Study on Application of Foamed Cement for Back Filling behind Abutment at Warp Land Dam Foundation in Northern Shanxi

The sections having geological conditions of warp land dam along Yan’an-Yanchuan Highway were selected to carry out high backfill behind abutment in virtue of the design, construction technology and quality control of foamed mixture lightweight soil, and then the mechanical properties and earth pressure (lateral pressure) thereof and the subgrade settlement were taken into supervision. The result shows that, for warp land dam foundation (with the bearing capacity thereof being 100 kPa only), foamed cement may be used directly for back filling behind abutment; only simple leveling and rolling is required for the original foundation, and the strength and deformability may meet the requirements. It is found on the basis of field monitoring that the lateral pressure on the abutment tends to be zero, the subgrade and foundation are not subject to obvious subsidence, and the bump at bridge-head may be reduced.