Addressing severe slope failure hazards along Sichuan-Tibet Highway in Southwestern China

Abstract

This paper presents the results of recent field investigations on the geological hazards along the Sichuan-Tibet Highway in Southwestern China. It was found that one section of the highway has been facing severe problems in slope failure. This is the section between Linzhi and Basu and it has been the most dangerous part of the highway system to road users over the last fifty years. Based on the examination of structural geology, Quaternary geology, stratigraphy and petrography, this paper presents the classification, distribution and hazard levels of the slope failures along the highway section. The failures usually occurred in slopes comprising Quaternary glacial deposits, fluvio-lacustrine deposits and residual soils. They can be classified as landslides, mud-rock flows, grain flows on slopes and rock avalanches. They are caused by four main factors: a) intense active tectonic movements, b) on-going alpine canyon relief, c) heavy precipitation and d) irrational human activities. The paper further discusses the engineering measures adopted by the relevant organizations over the past fifty years. Based on the investigations, the paper summarizes some useful recommendations to effectively address and mitigate the severe slope failure hazard problem for safe operation of the highway and future railway systems.