滨海地区细砂填料改良的试验研究

滨海细砂级配不良、CBR值不满足高等级公路路床填料要求且难以压实，作为路床填料时，需要进行改良处理。通过对试验室水泥改良砂、碎石改良砂试验结果进行分析，阐述了改良砂土的CBR、回弹模量与水泥掺入量、碎石掺入量以及压实度的相互关系，得出了水泥改良砂和碎石改良砂的适宜掺入量以及改良砂的压实度要求；通过干湿循环试验及不同浓度的硫酸镁溶液腐蚀性试验，评价了水泥改良砂的耐久性；通过动三轴试验得出了两层水泥改良砂填料摊铺的时间间隔要求，评价了上层水泥改良砂碾压振动荷载对下层的影响。

Experimental Study on Improvement of Fine Sand Filler in Coastal Area

The fine sand in coastal area has bad gradation with the CBR value not satisfied to be the filler for high class highway roadbed, and it is difficult to be compacted. Therefore, as the roadbed filler, it is required to be improved. Through the data analysis of test results from laboratory cement-improved or gravel-improved sand, the relations between the CBR, resilience modulus, cement content, gravel content and compaction degree of the improved sand were elaborated, and the proper content of cement-improved or gravel-improved sand and the required compaction degree thereof were found out; furthermore, the durability of cement-improved sand was evaluated by means of cyclic wetting and drying test and corrosion test of magnesium sulfate solution in different concentration; and through dynamic triaxial test, the time interval required to pave the two-layer cement-improved sand filler was obtained, and how the vibration load from rolling compaction of cement-improved sand in upper layer affects the lower layer, was evaluated.