ABSTRACT

Pore pressure development in loose sand layers can trigger instability and failure of earth structures. Static liquefaction is one of the most common consequences of instability, wherein pore water pressure increments under static loads lead to a decrease in the effective stresses and partial or complete liquefaction of the soil matrix. However, there is an ambiguity in the definition of static liquefaction, linking it to a number of fundamental features such as soil properties, effective stress levels and stability of particle arrangements in the soil matrix in undrained element tests. The results of static liquefaction model slope experiments show two consecutive phases of behaviour. First, a gradual change in the excess pore pressure, and subsequently the occurrence of both very fast accelerations and simultaneous excess pore pressure generation which characterize the onset of instability. The experiments are performed in a unique large scale testing device; a so-called static liquefaction tank.