土体的微观孔隙结构特征对其渗透性有着显著的影响,膨润土具有很强的防渗性能,在土中加入膨润土可改变其孔隙尺度分布和结构特征而降低土的渗透性。采用压汞仪法（MIP）试验研究了掺加不同比例的膨润土的细颗粒土的微观孔隙结构特征。试验结果表明：只要加入少量的膨润土便可使土体的大孔隙的数量急剧减少;随着膨润土的含量的增多,孔隙尺度分布逐渐发生变化,中孔隙的数量逐渐减少,小孔隙、微孔隙和超微孔隙的数量逐渐增多,孔隙分布密度函数由三峰态转变为双峰态,峰值所对应的孔隙直径减小。实验结果也证明了同一孔隙比的土样的孔隙特征的多“,”The micropore structure characteristics have significant influence on permeability of the soil,and bentonite is high anti-seepage material,which is added into the soil to reduce the peamiability by changing the pore-scale distrbution and pore characterist