高速公路建设中水土流失预测模式研究

Research on Prediction Model of Water Loss and Soil Erosion in Freeway Construction

针对山区高速公路建设的特点和可能造成水土流失的影响及其分布特性，根据国内外对水土流失预测的研究现状。选择了住于西南土石山区在建国道108线西攀高速公路路段的黄水互通式立交A匝道开挖边坡和K11＋100～K11＋210路段左侧的弃渣场上进行了观测试验，通过15次降雨量和水土流失量的实测，经过降雨强度、各时段降雨动能、降雨总能量参数单因子和复合因子与土壤流失量的相关分析，得出试验区的天然降雨雨滴中数直径与雨强的对数关系和单位降雨强度与降雨动能的关系；初步提出适用于高速公路建设土壤流失预测中的降雨侵蚀力的计算公式、土壤可侵蚀因子值；修正了经验法中的加速侵蚀系数A值。

Based on character of freeway construction in mountainous area, effect and distribution of probable water-soil loss as well as the status of its research home and abroad for prediction, two locations were selected, as test observing sites, on the Xichang-Panzhihua Freeway, the National Highway 108 which was under construction where it was in soil-rocky mountainous area of Southwestern China. One was a digging side slope of a ramp of Huangshui Interchange. The other was a dump at the left side of the section of K11 ＋ 100 -K11 ＋210. Rainfall and water-soil loss were observed quantitively for 15 rains, based on the data obtained correlation analysis was conducted between quantity of soil loss and factors such as rainfall intensity, rainfall kinetic energy of every period and rainfall overall energy, which function as single factor and/or multiple factor. The results obtained included： firstly a logarithmic relationship between diameter of natural raindrop median and rainfall intensity and a relationship between specific rainfall intensity and rainfall kinetic energy; secondly a formula proposed to calculate rainfall erosion and the value of soil erosion factor for prediction of water loss during freeway construction; and thirdly, modification of the value of accelerated erosion coefficient A in empirical formula.