中尼铁路夏木德至加德满都段主要工程地质问题及地质比选

Main Problems in Engineering Geology and Geological Alignment in Xiamude-Katmandu Section of China-Nepal Railway

拟建中尼铁路夏木德至加德满都段穿越喜马拉雅山脉,具有新构造运动及地震强烈、构造应力场强烈、岩浆活动强烈、水热活动强烈、重力夷平面下切强烈、物理风化强烈的特点。活跃的内外力地质作用导致该区工程地质条件极其复杂,边坡稳定性、泥石流水毁、高地温热害、高地应力下硬质岩岩爆、软岩大变形及深大活动断裂错断效应构成了控制线路方案的主要工程地质问题。研究认为:夏木德经吉隆至加德满都(AK)方案走行于吉隆藏布峡谷区,自然坡降相对较缓,有设口岸站条件,受地震影响较小,线路走向与主应力方向近乎平行。夏木德经聂拉木至加德满都(A1K)方案走行于波曲高山峡谷区,自然坡降相对较陡,设站条件困难,地层虽以硬质岩为主,但活跃的内外力作用,导致主要地质问题更为发育。从边坡稳定性、泥石流水毁、高地温热害、高地应力下硬岩岩爆及软岩大变形主要地质问题综合考虑,AK方案优于A1K方案。

The proposed Xiamude-Katmandu section of China-Nepal Railway through the mountains of Himalaya is characterized by neotectonic movement and strong earthquake, strong tectonic stress field, heavy strong magmatic activity, intense water and heat activity, fierce shear of the gravity planation surface and serious physical weathering. The active internal and external geological forces lead to the extremely complicated environmental engineering geological conditions and the railway track is much affected by the geological disasters, such as slope stability, damage by debris flow, heat damage of high ground temperature, hard rock burst and large deformation of soft rock under high ground stress, large active faults effect. The results suggest that the Xiamude-Gyirong-Katmandu （AK） solution running in the Geelong Zangbo gorge area is encountered with relatively slow natural slope, favorite port station conditions and less earthquake impact, where the direction of the railway is nearly parallel to the direction of the principal stress. While, The Xiamude-Nyalam-Katmandu （A1K） solution running in the Yu Bo Mountain canyon area is met with relatively steep natural gradient, difficult station conditions, although the stratum is formed mainly with hard rock, the internal and external forces are active and the main geological problems tend to get more intense. In view of the slope stability, damage by debris flow, heat damage of high ground temperature, hard rock burst and large deformation of soft rock under high ground stress consideration, the AK solution is proved superior to the A1K solution.