Abstract：Based on time-temperature superposition principle：a new creep equipment was designed to study the grogrids HDPE50 creep characteristic under confined load(100 kPa) and no confined load. Based on time-temperature superposition principle：the master curves were obtained from creep curves at different temperature to determine the creep reduction factor accurately. The value of C1，C2 calculated inversely by the tests data verify the rationality of the tests. The research indicate that：the effect of confined load on geogrids creep is obvious：the long time(106 h) creep value under confined load is 37% smaller than that under no confined load. The creep reduction factor calculated by time-temperature superposition creep test considered with confined load and conventional time-temperature superposition creep test RFCR1：RFCR2 is 2.4，1.8 respectively. The creep reduction factor RFCR3 calculated by the existing specifications is 1.7. Compared to the RFCR2，RFCR1 and RFCR3 will make the cost increased by 17%，25% respectively when applied to the same project design. The calculation of creep reduction factor in time-temperature superposition creep test considered with confined load is suggested to use the tensile strength under confined load：the design of project is suggested to use RFCR2.
HESIEHL C W，LEE K，YOO H K，et al. Tensile creep behavior of polyester geogrids by conventional and accelerated test methods[J]. Fibers and Polymers，2008，9(4)：476-480.
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LI R Z. Time-temperature superposition method for glass transition temperature of plastic materials[J]. Materials Science and Engineering A，2000，278(1)：36-45.
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2015, Vol. 34 
