Landslide mechanisms and protection of highways in frozen regions of northeast China

Abstract

Disasters caused by permafrost thawing have increased in permafrost regions in recent years due to changing climate and expansion of human activities. Heilongjiang Province is located in northeast China, where frozen soil is widely distributed. During highway construction, landslides caused by soil freeze-thaw have occurred often, much affecting slope stability and traffic safety. We have studied the effect of seasonal frozen soil freeze-thaw and permafrost thawing on the stability of the highway subgrade and slopes using data from the completed Tong-San highway from Harbin to Jiamusi and the Jihei highway under construction from Bei'an to Heihe. The study was divided into two parts: 1) for the Tong-San highway from Harbin to Jiamusi, the landslide mechanismas well as the protectionmechanism of soil containing woody roots were studied; 2) for the Jihei highway from Bei'an to Heihe, the mechanism of mountain body landslide was studied. These two studies are two IPL projects: IPL 132 (Research on Vegetation Protection System for Highway Soil Slope in Seasonal Frozen Regions), and IPL 167(Landslides Mechanism and the subgrade Stability Controlling Measures in Island Permafrost Area). The research was also funded by the Heilongjiang provincial government and the Chinese Ministry, to a total amount of 400,000 dollars. The work of IPL-132 has been completed, and some research results concerning protection of cut slopes have been adopted by the relevant departments of Heilongjiang Province in highway construction. The work IPL-167 is still ongoing.