Abstract
In this study, we tried to examine the accuracy of estimation for stress-strain curve in biaxial extension condition which was calculated by strain energy density function of waterproof sheets laid on a seepage structure in a controlled waste disposal site. The partial differential value of the strain energy density function was determined by the pure shear test. After a comparison between calculated stress-strain curve and that from the biaxial extension test, calculated values were correspond with the testing data within 10% error for the range from 15 to 40% strain for PVC, 3 to 4% for HDPE and 6 to 15% for SMePE. The previous study says that the strain of waterproof sheet made of PVC laid on backfilling unevenness was at most 15%. Thus, we suggest that the application of strain energy density function for the evaluation of waterproof sheet deformation due to unevenness of backfilling slope in a controlled waste disposal site should be possible.
