Model tests of freeze-thaw behavior of geocell-reinforced soils

Abstract

Freeze-thaw cycles are a major cause for destabilizing pavements in cold regions. Among countermeasures for freeze-thaw damages, use of geocells to reinforce pavement bases is an effective solution in practice. However, as opposed to widespread applications, research concerning freeze-thaw behavior of geocell-reinforced bases is limited, probably due to a lack of proper devices for conducting experimental tests. This paper presents a new model-test device capable of performing both freeze-thaw tests and plate loading tests on geocell-reinforced soils. A thermodynamic numerical model was developed to assist with the design of freeze-thaw component of the device, while the design of plate loading component was developed by referring to features of existing devices. Eleven tests were run on geocell-reinforced and unreinforced sands to confirm the effectiveness of the proposed device. The test results showed the device successfully provided vertical heat transfer in sands during freeze and thaw. After five freeze-thaw cycles, geocells reduced peak frost heave and thaw settlement of sands by 18% and 34%, respectively, and increased the stiffness and bearing capacity by 40% and 253%, respectively. It was found a temperature drop occurred at the interface between cooling plate and sands, which was due to the existence of thermal contact resistance.