结构性软土渗透特性研究  

Permeability of structural soft soils

作　　者：孙德安[1] 许志良[1] 

机构地区：[1]上海大学土木工程系,上海200072

出　　处：《水文地质工程地质》2012年第1期36-41,共6页Hydrogeology & Engineering Geology

摘　　要：本文对原状软土和重塑软土进行渗透特性试验,考察了饱和软土的渗透特性。原状样加载初期,渗透系数变化较小,当固结应力大于结构屈服应力时,渗透系数急剧下降,而结构屈服应力前后阶段的孔隙比与渗透系数对数坐标的直线关系没有发生变化,说明胶结对渗透性的影响较小。重塑土的渗透系数在加载过程中变化相对较小。试验结果表明,相同孔隙比时原状土渗透系数要明显大于重塑土。这是由于两者的组构不一样,即原状样的大颗粒和凝聚体间的大孔隙以及历史上形成的土颗粒的排列使其渗流通道要比重塑土通畅。用相同重塑方式制样得到的不同含水量土样,其渗透系数值相近;而用不同重塑方式制样得到的相近含水量土样,其渗透系数相差相对较大。确定饱和软粘土渗透性时要考虑孔隙比和组构的影响。The permeability characteristics of natural soft clays and corresponding remolded clays were investigated in laboratory.The coefficient of permeability of soft clays changes little at the early loading and changes sharply during loading beyond the structural yielding stress.The relationship between void ratio and logarithm of permeability is almost the same before and beyond the structural yielding stress,indicating that the effect of bonding on the permeability is small.The change in the permeability of remolded clays is relatively small.At the same void ratio,the permeability of undisturbed soil is greater than that of the corresponding remolded clay.This is due to different fabrics,i.e.,undisturbed soil is different from remolded soil in the macropore between large particle and the floccules and in the formation of soil particle alignment in the history.The coefficient of permeability is almost the same for remolded soils with the same remolding method and different initial water contents.Even if void ratio is the same,the coefficient of permeability is different due to different ways of remolding.Void ratio and fabric are necessarily considered for determining the coefficient of permeability of clays.

关 键 词：结构性土 渗透系数 渗透指数 组构 胶结 固结试验 

分 类 号：TU443[建筑科学—岩土工程]