细粒含量对粗粒土冻胀特性影响的试验研究

Influence of fines content on frost heaving properties of coarse grained soil

为了得到同时满足冻胀率和击实效果的最大细粒土含量,通过葡氏击实和冻胀试验,研究了不同细粒土含量、不同干密度条件下细圆砾土填料的冻胀特性。研究结果表明,9%细粒土含量下细圆砾土试样的压实效果最好;细圆砾土试样的冻结过程可以划分为快速冻结区、过渡区、似稳定区和稳定区;细粒土含量低于10%时,细圆砾土属于弱冻胀填料;同时满足冻胀率和压实效果的最大细粒土含量为9%;细粒土含量相同时,细圆砾土试样的冻胀率随干密度的增加,先增大而后减小,即存在一个最不利干密度;冻结48 h后,细圆砾土试样冻土段的含水率均大于初始含水率,其不同位置含水率分布曲线呈S型,且随着细粒土含量的增加逐渐呈现倒三角形分布;细圆砾土试样干密度的增大有效地阻断了水分迁移路径。

In order to obtain the maximum fines content meeting frost heaving ratio and compaction effect simultaneously,the frost heaving properties of fine round gravel soils（FRGS） under different fines contents and dry densities are studied by means of standard Proctor compaction tests and frost heaving tests.The results show that the optimum fines content of compaction effect for FRGS samples is 9%.The freezing process of FRGS samples can be divided into four stages,namely rapid freezing area,transition area,sub stable area and stable area.The FRGS is weak frost heaving fillings when the fines content is below 10%.The maximum fines content is 9% which is meeting the frost heaving ratio and compaction effect simultaneously.The frost heaving ratio of FRGS samples increases firstly and then decreases with increasing of dry density;namely there is a most unfavorable dry density.After 48 h freezing,the frozen section water content of FRGS samples is larger than initial water content.The water content distribution curves present S-shape and then gradually present inverted triangle with increasing of fines content.The increasing of dry density effectively blocks the water migration path.