藏区高速公路路基设计主要技术探讨

我国藏区海拔高度大，地形陡峻高差大，断裂活动频繁，江河发育，生态脆弱，地质灾害频发，保护区、风景区多，工程建设条件困难，在此修建高速公路有着与内地高速公路设计不同的技术特点。目前我国藏区高速公路的建设还基本处于初期阶段，如何做到高速公路的安全、抗灾、经济、环保，并具有较好的工程建设可操作性，是藏区高速公路设计的难点和重点之一。本文以两条典型藏区高速公路为例，对高速公路路基设计的一般路基、高填深挖路基、特殊路基和土石方工程等主要分项内容，依据藏区特有的地质环境和人文环境，针对性探讨了路基设计中所要注意的关键点，这对我国将来藏区高速公路的大规模建设时，如何取得优质设计成果具有良好的借鉴和指导作用。

DISCUSSION ON THE MAIN TECHNICAL DESIGN OF HIGHWAY SUBGRADE IN TIBET

Tibet is well known for its high altitude, big elevation, steep terrain and frequent fault activity resulting in many reivers and ecological fragility followed by frequent geological hazards. Adding the widely distributed scenes, it is difficult to build an expressway due to its geological engineering condiditons. So, the design technology for Tibetan expressways should be diffierent from what for the inland expressways. At present, the expressway construction in Tibetan area are basically in the initial stage. How to ensure highway safety, avoid disasters, save economy, protect environment and gain good engineering construction operation is the key problem and the difficulty of Tibetan highway design. In this paper, two typical Tibetan highway are taken as examples to study the main item of expressway subgrade design including general subgrade, high embankment, deep excavation, special Subgrade, earthwork and other contents according to the geological environment in Tibetan area and the humanities. The key issues in design are discussed which should be paid attention to in the design of roadbed. The results may be taken as a good reference and guidance for obtaining high-quality design of the future Tibetan highway.