冲击碾压法快速处置粉土路基的应用研究

针对黄河冲积平原区粉土路基填料受含水率影响较大、难以晾晒、普通碾压技术难以压实、生产效率低的特点，选择冲击碾压法对路基分层填筑施工。通过调整路基分层填筑厚度和压实遍数进行现场冲击碾压试验，检测路基表面沉降量、峰谷高差、压实度及路基承载力，并对比分析了3种不同虚铺厚度粉土路基的冲击压实效果。结果表明:表层土体压实度达到或超过93%后，压实度增长曲线出现拐点，继续碾压对提高土体压实效果影响越来越小，较难使层底土体压实度达到96%；路基填料允许的含水率ω范围为ω^opt-4%≤ω≤ω^opt+4%（ω^opt为最佳含水率）；推荐的最佳虚铺厚度为0.8 m，最适宜冲击碾压遍数为20，最佳碾压速度为10～12 km·h^-1；建议把沉降量和峰谷高差作为检测压实效果的辅助指标。

Application Study of Impact Roller Compaction Method to Strengthen Silt Subgrade

According to the characteristics of the Yellow River alluvial plain silt subgrade filling including influence by moisture content, difficult to dry, difficult to compact with ordinary rolling technology, and low production efficiency, the impact roller compaction method was chosen in construction. Through adjusting the subgrade layer thickness and compaction pass number, the impact roller compaction test was conducted to detect the surface settlement, peak valley depth, compaction degree and bearing capacity of subgrade. The impact compression effects of three virtual thickness silt subgrades were compared and analyzed. The results show that compaction degree curve appears inflection point when compaction degree of surface soil reaches or exceeds 93%, and the effect of continue rolling on improving compression degree of soil is getting smaller, then its difficult to improve compaction degree of bottom soil up to 96%. The allowed moisture content ?ω of subgrade filling can be controlled within ?ω^opt-4%≤ω≤ω^opt+4% (ω^opt is optimum moisture content) .The recommend silt virtual paving thickness is 0.8 m, the optimal rolling pass number is 20, the optimal rolling speeds are 10-12 km·h^-1. The surface settlement and peak valley depth should be taking as auxiliary indexes to evaluate the compaction effect..