Performance of plastic drains, i.e. drains made of plastic material, was stuided as to whether they are applicable as a countermeasure against soil liquefaction. The shaking table tests and analyses were conducted upon typical plastic drains of which cross sections were rectangular and circular. The cross sectional areas of both of the plastic drains were 20 cm2. The drains were installed in the model ground of the depth of 90cm at the spacing of 50cm and 75cm. Apart from the model tests, design charts were made for determining the spacing of plastic drains based upon the method proposed by one of the authors for gravel drains.
　The results of the model tests and analyses indicate that the plastic drains of both types of cross sections are applicable as a countermeasure against liquefaction. The applicability of the design charts for determining the spacing of plastic drains is also confirmed by the present study.