重庆奉云段高速公路水土流失预测

根据高速公路水土流失特点采用时空二维法分施工期、运营初期两个时段对重庆奉云段高速公路水土流失防治责任范围内的扰动地表区、弃渣场、表土临时堆置区、桥涵基础弃渣水土流失量进行预测。预测结果表明：高速公路水土流失总量为46．28万t，新增水土流失量42．07万t，水土流失新增指数为9．99，其中弃渣场、扰动地表区新增水土流失量分别占水土流失总量的54．58％、42．07％，弃渣场和扰动地表区是严重水土流失区；施工期水土流失强度为运营初期的59．32倍，是严重水土流失时段。对USLE在高速公路水土流失预测中参数取值方法也进行了较为系统的分析。

Discussion on Prediction of Soil and Water Loss on Chongqing Fengyun Expressway

According to the characteristic of water and soil loss in expressway, the project was classified into four parts including disturbed area, residue pits,surface soil pits and residue pits of bridges in two periods which were construction period and traffic-operating period. Then space-time two-dimensional method was used to forecast water and soil loss in Chongqing Fengyun expressway. The results show that in Chongqing Fengyun expressway water and soil loss may be up to 462.8 thousand ton by prediction and cause a new increase of 420.7 thousand ton that is mean the newly increased index of water and soil loss reach to 9.99. In the residue pits and disturbed area of the expressway the newly increased water and soil loss get to 54. 58% and 42.07% of the total amount of water and soil loss respectively. So the residue pits and disturbed area are the most serious water-soil erosion areas. The intensity of water and soil loss in construction period is 59.32 times as it in traffic-operating period, so this time is the most serious water-soil erosion period. The method is systematically analysed to select the indexes in USLE for the predietion of water and soil loss in expressway.