Force on structures caused by oscillation of liquefied silty soil

Abstract

Liquefaction is a very important form of seabed instability under strong wave action, and it concerns ocean engineering designers. Many works have been performed on the influencing factors and discrimination of liquefaction occurrence and development processes, which provide a better understanding of this phenomenon. The flume test shows that liquefied soil oscillates with waves, which poses a serious threat to the stability and structural strength of seabed structures. In this paper, the oscillation of liquefied soil and induced force on structures (such as piles and pipelines) buried in the liquefied soil are studied. The oscillation of liquefied soil under given conditions is calculated using the two-layer fluid wave theory and tested by the measured value through the falling ball method. Then, according to the results of the wave flume test and Morison equation, the relationship between the velocity of liquefied soil and the force on the structure is determined. The result shows that the two-layer fluid wave model can correctly describe the oscillation of liquefied soil after modification by a coefficient of 1.61, and the force on the structure caused by liquefied soil oscillation is proportional to the square of the velocity of liquefied soil with a scale factor of 150.2.