Experimental and Numerical Analyses of Freezing Behavior of an Embankment in Cold Regions

Xiaoxiao Luo,Fujun Niu,Wenji Su,Qinguo Ma,He Hu

doi:10.1155/2019/1437904

Abstract

Frost heave is the prevailing damage to the embankment in cold regions. It is a challenge to ascertain frost damage behavior of the embankment due to the complication of freezing-thawing process involving water migration, heat convection process of water, ice-water phase transition, and frost heave. To investigate the freezing behavior of the embankment, a hydro-thermo-mechanical numerical model is deduced, and an embankment model test is carried out. Finally, the moisture, temperature, and deformation during the freezing-thawing process are analyzed. The results show that (1) there exist two warm frozen layers and a frozen layer at the bottom of the embankment at the time of the minimum air temperature and at the time of the maximum thaw depth, respectively. (2) Under the drive of temperature gradient, the water migrates and the redistributions occur. The soil in the freezing-thawing front is filled with unfrozen water and ice, and its water content is high, which directly lead to frost heave. (3) The horizontal deformation at the shoulder is larger than those in other zones, which easily leads to denudation damage. Meantime, the deformation difference between the shoulder and middle will lead to the longitudinal cracks and consequently embankment failures. The study will provide a theoretical basis and reference for the design, maintenance and research of embankment in cold regions.

Highlights

Cold region areas account for about 50% of Earth’s land surface [1]
The results show that (1) there exist two warm frozen layers and a frozen layer at the bottom of the embankment at the time of the minimum air temperature and at the time of the maximum thaw depth, respectively
The following conclusions can be obtained: (1) Both the simulated temperature distributions and deformation variations of the embankment model are approximately similar to the measured ones, which mean that the hydro-thermo-mechanical numerical model can simulate the actual thermal-mechanical state of the embankment model

Summary

Introduction

Cold region areas account for about 50% of Earth’s land surface [1]. Many embankment projects have been constructed in cold regions, such as the Qinghai-Tibet Railway and Highway. Under the action of freezing and thawing, water migrates through the soil pores toward the freezing front, leading to the increase of water content in the freezing-thawing front This freezing-thawing cycle could adversely impose a huge modification of soil characteristics on the cold place countries annually [4,5,6,7]. In such places, soils are subjected to freezing and frosting heave in the winters and thaw settlement and weakening in the springs (Figure 1). It is important to analyze the hydro-thermomechanical process of embankment and investigate the frost behavior of embankment in cold regions

Objectives

Results

Conclusion