黄土拓宽路基足尺模型试验施工技术研究

Research on the construction technology of widening loess subgrade with full-scale model test

目的研究黄土拓宽路基的变形规律及其相关的施工技术,进行黄土拓宽路基足尺模型试验。方法根据产生不协调变形的组成部分,采用新老路基结合面处理、拓宽路基填料压实度控制、新旧路基结合面加筋处理以及拓宽路基检测技术等分析手段,明确施工控制的技术要点和施工方法。结果研究结果表明:1)拓宽路基最佳摊铺层厚度为20cm,碾压遍数为8～10遍,可以达到设计的压实效果;2)路基填料中,灰土的最佳含水量为13.7%,最大干密度为1.87g/cm3;黄土的最佳含水量为12.3%,最大干密度为1.95g/cm3;3)灰土路基的回弹模量明显高于黄土路基,较好地实现了新旧路基材料沉降变形特性的模拟。结论可以通过模型试验施工技术研究成果进一步了解拓宽路基施工的工艺流程和施工方法以及为其它路基拓宽工程中的处理措施的选择、设计和施工提供有益的帮助。

Aim To investigate the deformation rule and relevant construction technology of wide- ning loess subgrade by full-scale model test. Methods According to the components of the incoordi- nation deformation, the key points of construction control and construction methods is made clear through the treatment of the combination surface of the new and old subgrade and the control of degree of compaction of the widening subgrade surface as well as the reinforced treatment of the combination surface of the new and old subgrade and the detection technology for widening subgrade. Results The results showed that： 1） The designed compaction effect can be reached when the best paving layer thickness of widening subgrade is 20 cm and the times of compaction is 8 to 10 times; 2） In roadbed filling, the optimum moisture content and the maximum dry density of lime soil shall be 13.7% and 1.87 g/cm3 , respectively; the optimum moisture content and the maximum dry density of loess is 12.3% and 1.95 g/cma , severally; 3） Modulus of resilience of lime soil subgrade was signifi- cantly higher than that of loess subgrade, it better achieved the simulation of the characteristics of set- tlement deformation of the new and old roadbed materials. Conclusion The achievement in the research on the model test of construction technology can make people further understood the construction process and construction methods of widening subgrade and be helpful for the selection, design and construction of any other treatment measures for widening subgrade.