循环荷载作用下结构性软粘土的变形和强度特性

采用萧山原状和重塑软粘土在不同压力下固结后进行动力试验,探讨结构性软粘土在循环荷载作用下,合适的动应变破坏标准。文中比较了按本文提出的破坏标准与破坏应变标准取为5%和10%时的动强度差异,结果表明,在破坏振次较小时,本文提出的应变破坏标准更为合理;随着振次的增大,不同应变标准下的动强度差异性逐渐减小并趋于同一个稳定值--土体的最小动强度。固结压力对结构性软土动强度的影响较大,当固结压力小于土体结构屈服应力时,原状土动强度明显高于重塑土;而当固结压力超过土体结构屈服应力时,两者的动强度基本趋于一致。

Deformation and strength of structural soft clay under cyclic loading

An experimental investigation was presented to study the failure criterion of strain for natural and remolded soft clay of Xiaoshan. Compared were the cyclic strengths defermined with three failure criteria of strain, including 5% and 10% and that proposed by the author. There was obvious influence on cyclic strength defermined with different failure criteria of strain when failure cycle number was relatively small. While the number was large enough, the difference befween the cyclic strengths defermined with different failure criteria of strain decreased with increase of failure cycle number and a minimum cyclic strength was obtained. The confining pressure had an important influence on the cyclic strength of structural soft clay. The cyclic strength of natural soft clay was higher than that of remolded soft clay when confining pressure was smaller than the structural yield stress. Otherwise, the former would be close to the latter.