基于渗透破坏试验的粘土临界坡降影响因素分析

Influencing Factor Analysis of Clay Critical Hydraulic Gradient Based on Experiment of Seepage Failure

为分析粘土临界坡降的影响因素,以合肥某基坑土样为例,首先开展单一粒径级土体的渗透破坏试验,分析临界坡降随干密度和均值粒径的变化规律;其次,开展多粒径混合粘性土的渗透破坏试验,讨论在干密度一定时,不均匀系数、曲率系数对临界坡降的影响。结果表明,干密度对土体临界坡降影响最为显著,均值粒径次之,临界坡降随干密度三次方的增加而线性增加,随均值粒径的增加而线性减小,随孔隙率的增大而减小;不均匀系数对土体临界坡降影响较为显著,曲率系数次之,临界坡降随不均匀系数、曲率系数的增加而线性减小。

In order to analyze the influencing factors of the critical hydraulic gradient of clay,the soil samples of a foundation pit in Hefei were taken as examples.This paper firstly carried out the single particle sized clay's seepage failure experiment,and the change rules of critical hydraulic gradient with dry density and average particle size was analyzed.Secondly,the multi-sized grain clay's seepage failure experiment was carried out.The influence of uniformity coefficient and curvature coefficient on critical hydraulic gradient was discussed under the same dry density.The results show that the impact of dry density on clay critical hydraulic gradient is the most significant,the average particle size is the second;the critical hydraulic gradient increased with the three cubed dry density's enhancement,decreased with the average particle size's enhancement,and decreased with the porosity's enhancement;the impact of uniformity coefficient on clay critical hydraulic gradient is the most significant,the curvature coefficient is the second;the critical hydraulic gradient decreased with the enhancement of uniformity coefficient and curvature coefficient.