In this paper, instead of glass fiber, a bio-fiber (piemarker fiber) was used to reinforce unsaturated polyester (UP). UP resin was reinforced with piemarker fiber (PF) in a mold under hot pressing. The mechanical properties of the result composites were tested and hot pressing procedure was optimized. The optimum hot pressing technology was obtained. When hot pressing temperature was 90°C and mat was hot pressed for 1.5h. The mechanical properties of the composites indicated that: the optimum mass ratio of piemarker fiber to UP was 30:70, at which the flexural strength of the composite was 48.77MPa, the tensile strength was 29.082MPa, and the impact strength was 9.89KJ/m2.

To investigate the influence of seasonally frozen ground on frost-heave force of artificial frozen wall, 6 artificial frozen wall model tests were performed with different temperature of seasonally frozen ground on developed test platform. Experimental data indicate that compared with the final horizontal frost-heave force of artificial frozen wall without seasonally frozen ground, it increased 8.6% and 9.1% with-3°C and-12°C seasonally frozen ground layer, separately, and it shows that there is an important influence of seasonally frozen ground on the horizontal frost-heave force of artificial frozen wall. It also can be concluded that the lower the temperature of seasonally frozen ground is, the less the freezing time is and the bigger the final horizontal frost-heave force is, but, among all the model tests, the freezing time that is taken to get a stable state is the most for the artificial frozen wall without seasonally frozen ground , and its the final horizontal frost-heave force is the smallest.