安溪县花岗岩崩岗土体水分特征曲线及其影响因素

Water Characteristic Curve and Its Influence Factors of Granite Benggang soil in Anxi County

为研究花岗岩崩岗土体水分特征曲线及其影响因素,以福建省安溪县崩岗崩壁土为对象,通过压力膜仪对土体进行脱湿试验,绘制出崩壁土体水分特征曲线,并进行曲线参数与影响因素的相关分析。结果表明:随崩壁土体垂直深度增加,崩岗土体塑性指数、黏粒含量、分形维数及磨圆度等均整体呈降低的趋势;水分特征曲线斜率随着深度的增加而增大,土壤持水能力减弱,残余含水率及VG模型参数ɑ却随之减小,而参数n却随之增大;残余含水率、参数(ɑ、n)均与容重和颗粒的磨圆度呈极显著相关;残余含水率可用容重和黏粒含量描述,参数ɑ可用容重和形状比率描述、参数n可用容重和塑性指数描述。研究结果可为崩壁非饱和土的强度试验提供参考。

In order to examine the soil water characteristic curve and its influence factors of granite benggang soil,the soil of collapsing gully wall in Anxi County of Fujian Province was taken as the object.Experiment on soil dehumidification was conducted by using the pressure membrane meter,and the soil water characteristic curve of the collapse wall soil was drawn,then the correlation analysis of the curve parameters and the influence factors was carried out.The results showed that the plastic index,clay contents,fractal dimension and roundness were all decreased generally with the increasing vertical depth of the collapsed wall soil.Meanwhile the slope of soil water characteristic curve increased with the increase of vertical depth of the collapsed wall soil,also the water holding capacity,the residual water contents and the VG model parametersɑdecreased,but the parameters nincreased.The residual water contents and parameters（ɑ,n）were all significantly correlated with bulk density and roundness.The residual water contents could be described by bulk density and clay content,the parameterɑcould be described by bulk density and shape ratio,the parameter ncould be described by bulk density and plastic index.The findings can provide reference for the strength test of collapse wall unsaturated soil.