Investigation of the Bearing Capacity and Dynamic-Elastic Behavior of Mechanical Stabilization of Sandy Subgrade Using Geocells

There are many highway engineering researches conduced in China and many efforts were concentrated on the deserts of the great northwestern region. Due to the lack of good quality subgrade materials, it is necessary to consider improving the sandy materials locally available with geocells and used as subgrade economically. In order to fully understand the reinforcing behavior of geocells, both static and dynamic plate loading tests were conducted on the same sandy materials. For static tests, the test specimens are 60 cm (H) by 90 cm (W) by 150 cm (L) with two different geocell heights and two circular plate sizes (diameter of 20 cm and 30 cm) were used. For dynamic test, the specimens are 45.7 cm (H) by 45.7 cm (W) by 70 cm (L). Same geocell heights were used with smaller loading plate (5.08 cm and 10.16 cm). The loading conditions were 0.21 kg/cm2, 0.35 kg/cm2, 0.49 kg/cm2, 0.7 kg/cm2 and 1.05 kg/cm2. Experiment results indicated that geocell significantly upgraded the performance of sandy materials used in this research. The bearing capacity was improved 140% and the settlement was reduced. With a higher geocell, subgrade will have a higher bearing capacity and lower final settlement. Under repeated dynamic loading condition, the 15 cm high geocells had a higher initial settlement than the 10 cm ones. But the dynamic modulus of subgrade reaction will increase after 100 cycles. It showed that the initial settlement was a part of compaction process and it would benefit the long term performance.