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一、山区自然特征我国是一个多山国家,全国山区面积大约占总面积的1/3,北方山区(东北山林区)地势较为平缓,多为丘陵山地,平均地面自然横坡约在15°～20°之间。而南方山区多为山岭地带,地形、地质复杂,山脉连绵,山高谷深,峰峦起伏,山坡陡峻,平均地面自然横坡多在20°～35°之间。在自然横坡大的地段,地表土层簿、岩石暴露,形成悬岩陡壁、峡谷以及岩堆等复杂地形。山区气温随海拔高度变化,垂直性差异非常明显。降雨最一般是随海拔高度增加而增加,夏秋雨季多暴雨。由于南方山区具有上述的特殊地形、地貌、地质以及水文气象等地理特征,经常发生一些不良地质现象,如滑坡、泥石流、崩塌、岩堆、岩溶及雪崩等,危及公路
First, the natural characteristics of mountainous areas China is a mountainous country, the mountainous area of the country accounts for about 1/3 of the total area, the northern mountainous area (northeast forest area) is relatively flat terrain, mostly hilly, with an average ground natural slope of about 15 ° ~ 20 ° between. The southern mountainous area mostly mountainous area, topography, complex geological, rolling mountains, deep mountains and valleys, undulating hills and steep slopes, the average natural slope of the ground mostly between 20 ° ~ 35 °. In a large area of natural slope, the surface soil book, rock exposed, the formation of steep cliffs, canyons and rock piles and other complex terrain. Mountain temperatures vary with altitude, the vertical difference is very obvious. The most common rainfall increases with the altitude increases, more rain in summer and autumn rainy season. Due to the above-mentioned special geographical features such as topography, geology, hydro-meteorology and other geographical features, southern mountainous areas often experience some adverse geological phenomena such as landslides, debris flows, collapses, rock piles, karsts and avalanches,