杭州湾浅层粉土动力特性研究

Studyon the dynamic behavior of silt in shallow layer of Hangzhou Bay

选用杭州湾广泛分布的浅层粉土为研究对象,进行了一系列动三轴加载试验,研究了结构性、加载频率及动应力对杭州湾海底浅层粉土动应变、临界循环应力比和动强度的影响。试验结果表明,同一加载条件下,重塑样比原状样在更小振次内达到破坏,原状样动强度大于重塑样;结构性是影响土样动强度的重要因素,结构性对土样强度的影响随着动应力的增大而增强,随着频率的增大而减弱;加载频率的变化也对试样动力特性有较大影响,随着频率的增大,试样达到破坏所需振次加大,试样临界循环应力比也随之增大。

A series of experiments about dynamic triaxial apparatus were carried out to study the dynamic response behavior of silt from Hangzhou Bay.We studied the influence of structure,loading frequency,dynamic stress on dynamic strain,critical cyclic stress ratio,and the dynamic strength.The test results implied that,under the same loading conditions,the remoded samples are more likely to undergo structural failure than the undisturbed ones in smaller cycles.However,the dynamic strength of undisturbed soil is greater than that of remoded ones.Structural impact become an important factor influencing the dynamic strength of soil samples,the influence increased with the increase of dynamic stress,and decreased with the increase of frequency.On the other hand,the variation of loading frequency has significant effect on the dynamic characteristics of silt,the more frequency increased,the more cycles sample required to reach a failure,at the same time,the critical cyclic stress ratio of silt is also enlarged.