Numerical analysis of blast-induced liquefaction of soil

Soil has complicated properties that render the finite element modeling of blast-induced liquefaction very difficult. Recently, a numerical three-phase soil model has been proposed by the authors. This model contains all necessary elements for describing complex responses including the change of pore water pressure and degradation of the soil skeleton when subjected to extreme loading such as an explosion, and hence allows for the analysis and prediction of the liquefaction induced by explosion in the soil. In this paper, the three-phase model is applied to simulate the soil liquefaction. An overview of the three-phase soil model is provided first. The model is then employed to simulate physical experiments on the compressive behaviour of undrained soils under quasi-static and shock loading, respectively. Details about the porewater pressure and the effective stress on the soil skeleton are obtained from the numerical analysis and they compare well with the experimental data. An experimental case involving underwater explosion and liquefaction of a sand bed underneath is also analyzed using a coupled simulation with the three-phase soil model. The results show that the liquefaction zone can be simulated favourably. The effects of different shock loading on soil response and the assessment of the soil liquefaction based on the numerical results are discussed.