Liquefaction flow slides are recurrent phenomena in the Fraser River d
elta near Sand Heads. The reasons for these failures an unexplained an
d remained speculative. An investigation of a liquefaction flow slide
that occurred in 1985 in the Fraser River near Sand Heads has been und
ertaken using steady state concepts. For liquefaction flow slides to o
ccur in sand deposits, the sand must strain soften in undrained shear
and the in situ shear stresses must be greater than the available undr
ained shear strength. Laboratory tests have been performed on reconsti
tuted Fraser River sand samples to establish steady state parameters.
Moist tamping methods and water pluviation techniques were used for pr
eparing soil samples in the laboratory. Shear wave velocity measuremen
ts were used to evaluate the in situ state of the young, uncemented sa
nd deposits. The in situ state of the young sand deposits near Sand He
ads was found to be on the loose side of steady state, consistent with
the field observation of instability.