Understanding effect of freezing phenomenon in a fiber-reinforced soil structure is essential to foundation technology, road construction and earthwork application in cold region. This research aims to present the results of experimental investigation relative to the unconsolidated-undrained triaxial compression behavior of fine-grained soil as a function of freeze-thaw cycles and fiber volume fractions. All measurements were carried out for 3 selected glass and basalt fiber fractions (0%, 0.5%, and 1%) and 5 selected freeze-thaw cycles (0, 2, 5, 10, and 15). It has been observed that for the studied soil, strength of unreinforced soil reduced with increasing number of the freeze-thaw cycles while fiber-reinforced soil shows greater effect and the strength reduction amount reduces from 40% to 18%. Moreover, the reduction trend for cohesion of the fiber-reinforced soil decreased, this was seen more prevalent on 1% glass fiber-reinforced soil. The resilient modulus of all specimens reduced with increasing number of the freezethaw cycles. The experimental results demonstrated that different fiber fractions and their mixtures could be employed as supplement additive to improve the freeze-thaw performance of cohesive soils for road construction and earthworks.

This research presents the dynamic behavior of fiber-reinforced soil exposed to freeze-thaw cycles. The series of dynamic triaxial tests were conducted on fine-grained soil mixed with different percentages of basalt and glass fibers subjected to freeze-thaw cycles. The results showed that after freeze-thaw cycles, with the addition of basalt and glass fibers, the damping ratio and the shear modulus increased at a constant confining pressure because of the increase of stiffness, but the shear modulus decreased with increasing shear strain. Moreover, the theoretical analytical formulations were developed to define for dynamic shear stress and dynamic shear modulus. The parameters were predicted by Hardin-Drnevich model and Kondner-Zelasko model. The shear modulus was expressed as a function of freeze-thaw cycles, fiber contents, confining pressure and initial water content. Finally, ten coefficients were calibrated by analyzing the experimental results and then employed to describe dynamic shear modulus of the fiber-reinforced soil.

h i g h l i g h t s The thermal conductivity of soil decreased with the addition of fibers. Thermal conductivity of reinforced soil reduced when freeze-thaw cycles increased. The statistical-physical model provided good correlation with experimental data.

This paper presents the results of an investigation relative to the prediction of frost depths of seasonal freezing area in eastern Turkey. The Stefan equation and a modified Berggren equation are compared and utilized, and the computed results are compared with actual observed data. Also, the different harmful effects of freezing-thawing on highways in eastern Turkey are elucidated, supplemented with case studies. Based on this, the coldest areas are defined and a freezing depth contour map with the region's transportation network is produced. Some recommendations for the design and maintenance of subgrades in cold regions are provided.