粉土液化再固结过程中的波速特征及物理性质试验研究

Experimental Study on Wave Velocity Characteristics and Physical Properties of Silt During Liquefaction and Reconsolidation

强振动荷载作用下海底沉积物可能会发生液化。为了解粉土振动液化和再固结过程中波速特性与物理性质的变化规律,采用振动台试验模拟地震作用,针对不同状态的土体开展了波速测量和土体物理性质测试,研究了纵、横波速度的变化规律以及与物理性质之间的相关性。试验结果表明:与原始固结状态相比,粉土液化后纵、横波速度降低;液化再固结后土体纵、横波速度明显升高。纵、横波速度与沉积物物理性质具有良好的相关关系,与密度、平均粒径呈正相关,而与孔隙度、含水量具负相关性。相对于纵波速度,横波速度对沉积物的物理性质更敏感,能更好地刻画沉积物物理性质的变化。

The liquefaction of seabed sediments may induced by the action of strong vibration loads.In order to understand the variation between velocity characteristics and physical properties during the processes of silt vibrating liquefaction and reconsolidation,the shaking table test was used to simulate the seismic action.The wave velocity measurement and physical property test of soil were carried out for different status.The velocity variation of compressional wave and shear wave,and the correlation between velocity and the physical properties were investigated.The results show that the velocities of the compressional wave and shear wave are decreased in comparison with those in the original consolidation state,and the velocities are increased obviously after liquefaction and reconsolidation.The correlations between the velocity and the physical properties of the sediments are better preferable,which are positively correlated with the density and the average particle size,but negatively correlated with the porosity and water content.Compared with the compressional wave velocity,the shear wave velocity is more sensitive to the physical properties of the sediments,which can characterize the variation of sediments physical properties preferably.