穿越东非大裂谷工程地质与线路比选分析——以内罗毕—马拉巴铁路为例

内罗毕-马拉巴铁路工程是东非"北方走廊"的重要组成部分,是非洲内陆国家发展经济的主干线。铁路线路工程穿越的东非大裂谷,地质复杂、火山地貌、断裂带和拉张裂缝等不良地质极为发育,而东非大裂谷铁路工程建设的研究资料十分匮乏。为了研究穿越东非大裂谷的铁路线路,本文首先介绍了东非大裂谷地形、地貌、裂谷的发育机理、区域断裂分布,然后以铁路沿线经济控制点为主轴,制定了穿越东非大裂谷铁路线路3大通道。分别对线路3大通道穿越的地形、地貌比选,穿越的地层、断裂和地裂缝比选,穿越地震、火山发育比选以及穿越的不良地质灾害比选,最后比选各线路通道的投资以及优、缺点,最终推荐南线通道方案。该线路方案得到肯尼亚政府的肯定和采纳。目前内马铁路正试运营,实践表明内马铁路裂谷段选线是较为成功的,可为同类工程提供借鉴。

COMPARISON AND SELECTION OF ENGINEERING GEOLOGY AND ROUTES ACROSS EAST AFRICAN RIFT VALLEY——TAKE THE NAIROBI-MALABAR RAILWAY FOR EXAMPLE

The Nairobi-Malabar railway project is an important part of the "northern corridor" of East Africa. It is the trunk line of economic development in landlocked African countries. The railway line works pass through the rift valley. The volcanic landform, the fault belt and the tension fracture are extremely development. However, there is a lack of research data on railway construction in the rift valley. To study railway lines through the rift valley, firstly, this paper introduces the topography, landform, development mechanism and regional fault distribution of the east African rift valley, and then formulates three major railway routes through the east African rift valley based on the economic control points along the railway. We had compared the terrain and landform traversed by the three major routes, the stratum, fault and ground fractures, the earthquake and volcanic developments, and the adverse geological disasters. Finally, the investment, advantages and disadvantages of each route had been compared, and finally the southern route scheme was recommended. The scheme of the route was approved and adopted by the Kenyan government. At present, the Nairobi Malaba railway is in trial operation, and the practice shows that the selection of the rift section of Nairobi-Malabar railway is relatively successful, which can provide reference for similar projects.