**Abstract**

The Qinghai-Tibet Railway is a magnificent project in the twenty first century. However, the problem of land desertification has arisen during the operation of the railway. Many sections of the railway roadbed are buried by sand. The ecological safety along the railway and the safe operation of the railway have attracted worldwide attention. This chapter will focus on the current situation of desertification along the Qinghai-Tibet Railway, such as key desertification sections and the temporal and spatial characteristics of the occurrence of desertification. At the same time, it introduces the characteristics of the dynamic conditions of railway desertification and the source of sand material. It is divided into two parts: biological measures and engineering measures to introduce desertification control along the railway. The biological measures focus on the selection of *Lolium perenne*, *Festuca sinensi*, *Elymus breviaristatus*, *Elymus nutans* and *Poa crymophila,* and other alpine native sand-fixing plant materials. The engineering measures will introduce the railway desertification comprehensive prevention and control technology system that combines solidification, resistance, and transportation.

**Keywords:** Qinghai-Tibet, railway, desertification, sand prevention and control, biological measures

#### **1. Introduction**

The Qinghai-Tibet Plateau is the highest and unique physical geographic unit in the world. It has a significant impact on the ecological environment of China and its neighboring countries. For a long time, poor traffic conditions in the plateau area have greatly restricted the overall economic and social development of the region. The Golmud-Lhasa section of the Qinghai-Tibet Railway started construction in July 2001 and opened to traffic on July 1, 2006. The Qinghai-Tibet Railway project has fundamentally changed the traffic conditions in the Qinghai-Tibet Plateau, and promoted the reform and opening up of the region, the overall economic and social development, and the improvement of the living standards of the Tibetan people.

The Qinghai-Tibet Plateau has the characteristics of high altitude, low temperature, little precipitation, simple ecosystem structure, weak anti-interference ability, and vulnerability to global environmental changes, showing strong vulnerability [1]. The permafrost section of the Qinghai-Tibet Railway is about 550 km, and the section with an altitude of more than 4000 m is 960 km. The terrain and landforms in the line area are changeable, with high altitude, deep-frozen soil, strong winter wind, low temperature, and large temperature difference between day and night. Plants are difficult to root and have a short growth period [2]. The plants only have

#### *Deserts and Desertification*

a growth time of about 3 months. In addition, in recent years, due to the increasing global climate change and human disturbance, the trend of vegetation degradation is obvious. Once the vegetation in this area is destroyed, it is very difficult to restore [3]. The degraded grassland has become the source of railway sand-damaged materials [1]. In the long-term investigation and monitoring, it was discovered that the construction of the railway has changed the wind and sand environment along the line so that the wind and sand that could have passed through the border piled up near the roadbed. Sand accumulation on the trackbed directly affects the safe operation of railways [4]. At the same time, the accumulation of sand near the roadbed interferes with the protection measures of the railway's frozen soil, accelerated the melting of the frozen soil under the roadbed, caused the deformation of the roadbed, and caused greater harm to the safe operation of the railway. The sand disaster has seriously threatened the operational safety of the Qinghai-Tibet Railway, and it is one of the most severe sand-damaged lines in China [5].

However, there are still huge challenges in understanding the formation mechanism and distribution pattern of sand damage in the Golmud-Lhasa section of the Qinghai-Tibet Railway. Sand hazard prevention and control technologies were also just in their infancy. In the early stage of railway construction, the breeding and selection of native herbaceous plants used for vegetation restoration along the railway have been carried out, and certain results have been achieved. However, woody plants suitable for cold and dry environments have been extremely scarce. The supporting technologies for suitable artificial vegetation construction were insufficient. The traditional biological measures for sand prevention and control along the railway and the "tree, shrub, and grass" model are difficult to achieve. The existing sand prevention technologies along the railway have a series of problems such as high engineering cost, low efficiency, lack of materials required for biological measures, and imperfect comprehensive sand prevention and control system.

On the whole, in order for the Qinghai-Tibet Railway to become an environmentally friendly and safe railway, it is necessary to understand the distribution and characteristics of the severe and potential sand-damaged areas along the railway and strengthen the research on the mechanism and comprehensive prevention and control technology of sand damage along the railway. Urgent problems to be solved include degradation mechanism and protection technology of native vegetation around railways, rapid vegetation restoration technology, railway protection forest plant selection and planting supporting technology, and the combination of biology and engineering technology, etc. This chapter will introduce the distribution pattern and cause mechanism of sand damage, the research and development and integration of vegetation restoration technology, and the research and integration of engineer and plant sand control technology along the Qinghai-Tibet Railway.
