No guidelines are available on liquefaction evaluation of silt-clay and silty sand-clay mixtures under cyclic loading. The liquefaction behavior of these kinds of soils is not understood clearly at present. In this paper

according to the results of dynamic triaxial tests

the characters of cumulative pore water pressure and dynamic deformation of silt-clay and silty sand-clay in Tianjin are analyzed. The liquefaction evaluations of indoor tests are studied. At the same time

the results of wave velocity test in situ are compared to that of the indoor tests. As results

for the silt-clay and silty sand-clay in Tianjin under cyclic load

the value of water pore pressure tends to be stable when it is equal to 60 %-80 % of confining pressure; the corresponding value of double amplitude strain is 5 %. Therefore

these values can be used as the indexes of liquefaction evaluation.