新疆地貌及其过程对公路交通建设的影响

Influences of the Landforms and their Processes on the Construction of Highways in Xinjiang

新疆地域辽阔,有“三山两盆”,地形复杂,类型多样。山地、平原、沙漠、湖泊面积所占比重依次为39.11%、40.05%、20.48%和0.36%。山地与盆地海拔高差达8765m;以海拔500～1500m面积居多。坡度0°～3°的面积占67.77%;地形起伏0～50m/km2的面积占63.83%。受地貌条件的限制,公路不得不翻山越岭、在山麓平原连续跨沟和穿越沙漠。不同地貌类型特点各异,其对公路建设的影响不同。受新构造运动作用,山、盆高差大,现代地貌过程自盆地中心往周边高山依次是风蚀风积→流水堆积→干燥剥蚀→流水侵蚀→冰缘冰川寒冻作用,其中风力、流水、冻融及重力作用对公路的影响较大,主要是引起风沙、山洪泥石流、滑坡、崩塌等7种公路病害。针对地貌过程加剧引起公路病害发生特点,提出了6条防治建议。

The area of Xinjiang is vast, and its landforms are complicated and multiplex with a morphological pattern of the “two basins between three mountains'. The area proportions of the mountains, plains, deserts and lakes are 39.11%, 40.05%, 20.48% and 0.36% respectively. The relative elevation difference between the highest mountain and the lowest basin reaches 8765 m. The area in an altitude range of 500～1 500 m a.s.l. is dominant, and the areas in a slope range of 0～3°and an uplift range of 0～50 m/km occupy 67.77% and 63.83% of the total land area respectively. The highways have to be built to cross over the mountain after mountain, the irrigation canals, deserts and Gobi deserts in the piedmont plains due to the constraints from the physiognomy. The features of various geomorphologic types are quite different, which result in the different influences to the construction of highways. The height difference between the mountains and the basins is great, caused by the neotectonic movement. From the hinterland of the basins to the peripheral alpine zones, the modern geomorphologic action is in a devolution of wind erosion and sedimentation → fluviatile deposition → arid denudation → fluviatile erosion→ periglacial cold action → modern glaciation, in which the wind erosion, fluviatile action, freezethaw action and gravitation affect seriously the construction of highways and result mainly in 7 kinds of disasters on highways, such as wind erosion, floods and debris flows in the piedmont zones, landslides and landslips. In the paper, 6 suggestions are put forward for controlling these geologic disasters.