无侧限高压实高庙子膨润土非饱和渗透特性

Unsaturated Hydraulic Conductivity of Densely Compacted Gaomiaozi Bentonite Under Unconfined Conditions

摘要:

采用瞬时截面法试验研究了自由膨胀条件下高压实高庙子膨润土的非饱和渗透特性.结果表明,自由膨胀状态下,干密度为1.70 g·cm-3的高压实高庙子膨润土的非饱和渗透系数在1.0×10-12～1.0×10-15 m·s-1之间变化,且主要集中在1.0×10-14 m·s-1附近,达到饱和状态时渗透系数最大.与侧限条件相比,自由膨胀条件下的高压实高庙子膨润土的非饱和渗透系数大于侧限条件下的非饱和渗透系数,且渗透系数与吸力的变化趋势存在一定差异,这可能是由于不同侧限条件下其水化膨胀形式不同而造成的.

Abstract:

The unsaturated permeability of compacted Gaomiaozi-bentonite was tested under unconfined conditions on the basis of the instantaneous profile method.Results show that under unconfined conditions,the unsaturated permeability of Gaomiaozi bentonite ranges from 1.0×10-12 to 1.0×10-15 m·s-1 and groups around 1.0×10-14 m·s-1,and the maximum value reaches when the specimen is saturated.Compared to the confined conditions,the unsaturated permeability under confined conditions is lower than that under unconfined conditions,and the shapes of curves between unsaturated permeability and suction under different confining conditions are different.This may because that the swelling mechanism is different under different confining conditions.