【作者】 陈展鹏；

【导师】 张平仓；

【作者基本信息】 长江科学院 ， 水力学及河流动力学， 2009， 硕士

【摘要】 红壤和紫色土是长江中上游地区的两种最具代表的水蚀性土壤,目前该区域土壤厚度普遍仅30～50cm,只为黄土的1/200,在强烈的侵蚀作用下有限的土壤资源将很快流失殆尽。随着开发建设项目的大量增加,尤其是长江流域红壤、紫色土等主要水蚀区域,人们迫切需要对其造成的土壤侵蚀严重区域进行合理、科学的综合治理。因此,保护红壤和紫色土及防治其水土流失具有重要的意义。本论文主要针对原状和扰动的红壤、紫色土坡面侵蚀过程展开研究,根据开发建设项目水土流失自身的特点,力图阐明其水土流失机制,并推求加速侵蚀系数。本研究利用人工模拟降雨实验和径流小区、侵蚀槽的手段实测原状红壤、紫色土和扰动红壤、紫色土在不同坡度、不同雨强情况等条件下的产流产沙相关数据,并结合原状和扰动的红壤、紫色土的理化性质,通过比较分析原状红壤、紫色土和扰动红壤、紫色土的侵蚀过程、侵蚀率及其影响因素,得到其主要结论如下:(1)原状和扰动红壤、紫色土的初始产流时间均随着雨强的增大而缩短,相同情况下,红壤的初始产流时间比紫色土短,也就是说红壤坡面产流速度快于紫色土。(2)原状红壤、紫色土的产流过程受雨强的影响较大;相同的情况下,红壤径流小区的地表径流深大于紫色土径流小区。扰动红壤和紫色土产流过程比较相似,在坡度相同时地表径流深的随雨强的增大而增大。(3)原状红壤和紫色土的产沙过程随降雨历时的变化不尽相同:红壤径流小区产沙量均随降雨的进行逐渐增大至峰值,而后随着降雨过程波动;紫色土小区在0.8mm/min雨强下的整体趋势较平稳且无较大波动,但在1.1和1.4mm/min雨强下产沙量先随降雨历时逐渐增大到峰值,之后呈现下降趋势。扰动红壤和紫色土的产沙过程较为相似,在坡度相同时产沙量随雨强的增大而增大。(4)原状红壤和紫色土的侵蚀率有较大差异,小雨强时(0.8mm/min),红壤的侵蚀率大于紫色土;中大雨强时(1.1和1.4mm/min)与之相反。扰动红壤和紫色土的侵蚀率都表现出相似的规律,既侵蚀率随着雨强和坡度的增大而增大。(5)扰动红壤的加速侵蚀系数大多随着坡度的增加而降低。紫色土的加速侵蚀系数在20°坡15min时段达到最大,在此坡度条件下符合规律:45min时段加速侵蚀系数<30min时段加速侵蚀系数<15min时段加速侵蚀系数。更多还原

【Abstract】 Red soil and purple soil are two representative soils in the upper reaches of the Yangtze River. Generally soil depth in this region is only 30 ~ 50 cm as 1/200 as that of loess. Their nutrimental surface soil is strongly eroded and washed away. With the increase of development and construction projects in this region, the effective prevention and control measures are urgently needed to prevent and control soil loss. As a result, it is necessary to protect the red soil and purple soil and control their soil lossCombined with the soil loss characteristics of the development and construction projects, the purpose of this study is to analyze the soil erosion processes and mechanism of undistributed red soil and purple soil, distributed red soil and purple soil, and to estimate the expedited coefficient of soil loss. In this study artificial rainfall simulators, runoff plots and erosive grooves are used to collect the runoff and sediment yield data under four rainfall intensity and four slopes. Based on the collected data, the erosion processes, erosion rate and influencing factors of these two kinds soil were analyzed.The conclusions are as follows:(1) With the increasing rainfall intensity, the initial runoff time of undistributed red soil and purple soil, distributed red soil and purple soil decrease. And the initial runoff time of the red soil are less than the purple soil in the same condition, which shows the runoff velocity of red soil are greater than that of soil.(2) The rainfall intensity deeply affects the runoff processes of red soil and purple soil. In the same conditions the depth of runoff of red soil are greater than that of purple soil. The runoff processes of distributed red soil are similar with purple soil. The runoff depth of both kinds of soil increases with the increasing rainfall intensity at the same slopes.(3) The sediment processes of red soil are different with purple soil. The sediment yield of red soil gradually increases to peak value. Subsequetly it fluctuates. The sediment yield of the purple soil changes very small under 0.8mm/min rainfall intensity while it gradually increases to peak and subsequently decreases under 1.1 and 1.4mm/min rainfall intensity. The sediment production processes of distributed red soil are similar with purple soil, and the sediment production of both kinds soil increases with the increasing rainfall intensity at the same slopes.(4)The erosion rate of the red soil differentiates with the purple soil. The erosion rate of the red soil is bigger than purple soil under 0.8mm/min rainfall intensity, and it is opposite under 1.1 and 1.4mm/min rainfall intensity. The erosion rate of distributed red soil is similar with distributed purple soil, and the erosion rate of these two kinds of soil increases with the increasing rainfall intensity at the same slope. (5)The expedited coefficient of soil erosion of distributed red soil almost decreased as slope increases. The expedited coefficient of soil erosion of distributed purple soil reaches the maximum under 20°slope and 15min period, and when the slope is 20°, the relationship of expedited coefficient is: 45min periods﹤30min periods﹤15min periods.更多还原