游离氧化铁对压实花岗岩风化土崩解特性的影响

Effect of free iron oxide on disintegration characteristics of compacted weathered granite soil

为研究游离氧化铁对花岗岩风化土崩解特性的影响,使用还原-络合方法(DCB法)去除花岗岩风化土中的游离氧化铁,并在不同干密度及含水率条件下,以除铁前后两种土样为对象进行室内崩解试验,同时对两种土样进行电镜扫描(SEM)。结果表明:在同一干密度及含水率条件下,除铁后的花岗岩风化土试样完成崩解所需时间大幅增长,且崩解过程中崩解速率的变化更为稳定;在不同干密度及含水率条件下,两种状态的土样完成崩解的时长均随干密度及含水率的增长而增长。通过SEM观察到除铁前的土样中存在易被水破坏的桥状结构,可削弱花岗岩风化土在水中的稳定性。

In order to investigate the effect of free iron oxide on the disintegration characteristics of weathered granite soils,the reduction-complexation method(DCB method)was used to remove free iron oxide from weathered granite soils,and two soil samples were subjected to indoor disintegration tests before and after removal of free iron oxide at different dry densities and water contents.Scanning electron microscopy(SEM)tests were also conducted on the two soil samples.The test results showed that the time to complete disintegration of granite weathered soil samples after removal of free iron oxide increased significantly under the same dry density and water content conditions;and the variation of disintegration rate was more stable during the disintegration process.Under different dry density and water content conditions,the time to complete disintegration of soil samples in both states increased with the increase of dry density and water content.It was observed through SEM experiments that there were bridge-like structures in the soil samples before iron removal,which could weaken the stability of weathered granite soil in water.