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在多年冻土地区铁路路基工程中,人为上限(即季节最大融化深度)的合理计算对断面形式的合理设计具有重要的意义。人为上限受很多因素影响,通常可大致分二类:(1)构筑物及其附近土体特性指标及构筑物几何形状;(2)外界(上、下边界和地中热流)条件。 然而,青藏高原多年冻土地区腹部地带又具有下述特点:年平均气温低(-5—-7℃),年内负温期长达7个月以上,年内季节冻深超过季节融深,年平均地温较季节冻土区要低得多,在融化过程中由融化界面传入冻土中的热量成为不可忽视的影响因素。因此,必须分析其主要因素,以便使路
In railway subgrade projects in permafrost regions, the rational calculation of artificial ceiling (ie, the maximum melting depth in the seasons) is of great significance to the rational design of cross-section forms. The artificial ceiling is affected by many factors and can be broadly divided into two categories: (1) soil properties of the structure and its vicinity, and geometry of the structure; and (2) conditions of the outside world (upper and lower boundaries and geothermal heat flow). However, in the permafrost regions of the Qinghai-Tibet Plateau, the belly belt has the following characteristics: the average annual temperature is low (-5--7 ℃), and the negative temperature period is as long as 7 months or more during the year; The average ground temperature is much lower than that in the seasonal frozen soil area, and the heat input into the frozen soil from the melting interface during the melting process becomes an unavoidable factor. Therefore, we must analyze its main factors in order to make way