针对上海地区淤泥质粘土的原状土样(具有凝聚型结构)和重塑土样(具有分散型结构)进行一维压缩试验,探讨结构性对上海淤泥质软土次压缩特性的影响。结果表明,具有分散型结构重塑土的压缩指数Cc、次压缩系数Ca以及Ca/Cc为定值,并不随固结压力的变化而产生明显变化;但原状土在达到结构屈服强度时,由凝聚型结构向分散型结构转化,并造成Ce、Ca。以及Ca/Ce值迅速增大直至峰值,再随着压力的增大而减小。另外,结构上的大幅调整造成了原状土e-1gt曲线的反S特征不明显。
One dimensional compression tests were conducted on natural samples (with flocculated structure) and remolded samples (with dispersive structure) of Shanghai soft clay to study on the influence of soil structure on the secondary compression behavior of Shanghai soft clay. Results show that the compression index Co, coefficient of secondary compression C,, and CJCaof remolded samples are almost constant and don't change much with increase of consolidation pressure. When the consolidation pressure reach the yield strength of natural structure and the flocculated structure turns to the dispersive structure, Cc, Co and Ca/Cc increase quickly to the peak value and decrease as the consolidation pressure increase. What's more, the drastic change of soil structure will influence the dissipation of pore pressure, so the kind of anti-S shape of e-lgt curve isn't obvious in natural samples and it will be very difficult to determine the time tp, when prime consolidation finished and secondarv comoression beoan.