红层泥岩水泥改良用作路基填料的粒径效应分析

Analysis on Particle Size Effect of Red Mudstone Cement Improved as Roadbed Filler

针对红层泥岩水泥改良用作路基填料时,改良效果随颗粒粒径增大而减弱的问题,选取成达万铁路工程沿线典型红层泥岩风化物,进行不同控制粒径的红层泥岩水泥改良试验研究。结果表明:红层泥岩颗粒粒径越大改良效果越差,在水泥掺量为8%的条件下,最大粒径40 mm改良土的无侧限抗压强度约为最大粒径20 mm改良土的50%;考虑干湿循环作用,红层泥岩改良用作基床以下路堤填料的推荐水泥掺配比例为最大粒径5 mm时3%、最大粒径20 mm时4%、最大粒径40 mm时14%。

To solve the problem that the improvement effect of red mudstone cement weakens with the increase of particle size when it is used as roadbed filler,based on the typical red mudstone weathering along the Chengdu—Dazhou—Wanzhou Railway Project,the experimental study on the improvement of red mudstone cement with different control particle sizes was carried out.The result shows that,the larger the particle size of red mudstone,the worse the improvement effect.Under the condition of 8%cement dosage,the unconfined compressive strength of the improved soil with the maximum particle size of 40 mm is about 50%of that of the improved soil with the maximum particle size of 20 mm.Considering the effect of dry-wet cycle,the recommended cement mixing ratio for the improvement of red mudstone as embankment filler below subgrade bed is 3%when the maximum particle size is 5 mm,4%when the maximum particle size is 20 mm,and 14%when the maximum particle size is 40 mm.