砒砂岩区典型小流域复合侵蚀动力特征分析

Dynamic characteristics of complex erosion in a typical small watershed of soft sandstone area

以鄂尔多斯高原砒砂岩区水力、风力、冻融交错侵蚀作用为研究对象,选择准格尔旗二老虎沟小流域作为研究流域,对侵蚀环境参数进行定位观测,统计分析水力、风力、冻融作用的年内变化过程。采用数据标准化后的层次分析法,揭示水力-风力-冻融交错作用过程,辨识高侵蚀风险发生的时阈及动力交错模式。研究表明:砒砂岩区复合侵蚀作用可分为风冻交错、风水交错和风水冻交错三个典型动力组合模式,风水交错侵蚀是该地区的主要侵蚀模式;砒砂岩区年内存在三个高侵蚀风险期,即风-冻融交错侵蚀期(2月上旬至3月中下旬),风-水交错侵蚀期(6月中上旬至8月中下旬),水-风-冻融交错侵蚀期(10月中旬至11月中下旬)。

Taking the alternating erosion of water,wind and freeze-thaw in the soft sandstone area of Ordos Plateau as the research object,a small watershed named Erlaohugou in Zhun-ge-er County was selected to carry out locating observation of erosion environmental parameters,and to analyze the annual variation process of hydraulic,wind and freeze-thaw action. After the standardization of the data,an analytic hierarchy process(AHP) was used to reveal the alternating process of water-wind-freeze-thaw,and to identify the time threshold and dynamic alternating mode of high erosion risk. The results show that complex erosion in the soft sandstone area can be divided into three typical dynamic combination modes:wind-freezethaw interaction,wind-water interaction and water-wind-freeze-thaw interaction,among them,wind-water interaction erosion is the main erosion mode in this area. There are three periods of high erosion risk in the soft sandstone area in a year,that is wind-freeze-thaw alternate erosion period(from early February to mid-late March),wind-water alternate erosion period(from early June to mid-late August),and waterwind-freeze-thaw alternate erosion period(from mid-October to mid-late November).