【作者】 王其东；

【导师】 高海鹰；

【作者基本信息】 东南大学 ， 市政工程， 2016， 硕士

【摘要】 黄河中游砒砂岩区水土流失严重,给整个生态环境造成了极其恶劣的影响。目前关于该地区砒砂岩的侵蚀规律研究还不够深入,尤其缺乏模拟降雨试验数据,另外该地区的水土保持措施比较单一,化学材料措施很少推广应用。本研究首先通过室内模拟降雨试验,考察了坡度、降雨强度、植被覆盖度对砒砂岩坡面侵蚀特性的影响,并进行回归分析建立了砒砂岩坡面侵蚀预测模型；其次,通过室内降雨试验和野外放水冲刷试验相结合的方法,检验了新型固化剂W-OH在砒砂岩坡面的应用效果,主要得出的结论有以下几点：1)砒砂岩渗透性很差,一场降雨过程中降雨入渗量仅占到总降雨量的10%-15%,不同条件下坡面产流量随降雨历时趋于稳定,基本等于降雨量。各因素对坡面侵蚀产沙量的影响大小为：降雨强度>植被覆盖度>坡度。2)植被对砒砂岩坡面的减沙效益较减流效益更为明显,不同条件下植被的减流率在20%左右,而减沙率在70%左右,另外植被的减流减沙效益,受降雨强度的影响特别明显,更大的降雨强度时须对应更高的植被覆盖度,才能起到理想的减蚀效果。3)回归分析,得到砒砂岩坡面侵蚀总产沙量与坡度、植被覆盖度间均具有很好的线性关系,而同降雨强度具有较好的幂函数关系,并通过分析累计产沙量随时间的变化规律,建立了砒砂岩小尺寸坡面侵蚀预测模型。4)W-OH在砒砂岩坡面形成一层稳定的保护层,起到了隔水和疏水的效果,这大大削弱了水对砒砂岩的侵蚀作用,使得降雨侵蚀过程只有雨滴的溅蚀作用,而几乎没有径流冲刷和重力侵蚀作用。室内降雨条件下,W-OH的抗蚀效果明显,不同条件减沙率均超过98%；同样,室外条件下,其抗径流冲刷效果也非常显著,两种坡面类型的减沙率都超过99.5%。更多还原

【Abstract】 Pisha sandstone areas in the middle reaches of the Yellow River exist serious water and soil erosion, which has caused bad influence to the ecological environment. However, current research about erosion mechanism on this region is not enough, especially lacks rainfall simulation experiment data. What’s more, the region’s soil and water conservation measures have been old-fashioned, few chemical materials measures applied.First of all, in the indoor simulated rainfall conditions, the erosion rule of slope rainfall in Pisha sandstone region was studied from the aspects of rainfall intensity and slope gradient and the coverage of vegetation. Then through regression analysis, water erosion forecast model about Pisha sandstone slope was established. Secondly, by using indoor simulated rainfall experiment and outdoor runoff scouring experiment, the effect on increasing resistance to water erosion of Pisha sandstone by a novel hydrophilic polyurethane (W-OH) was examined. The main conclusions are the following:1) The permeability of Pisha sandstone is very poor. Within a rainfall, the infiltration water accounts for only 10%～15% to the total rainfall amount. With the increase of rainfall time, the runoff rate tends to be stable, basically equal to the rainfall intensity. The sediment yield is affect by different factors:the influence of rainfall intensity> vegetation coverage> slope.2) The vegetation coverage in Pisha sandstone has a more significant effect to sediment reduction than to runoff reduction. In different conditions, runoff reduction rate is about 20%, however sediment reduction rate is about 70%. In addition, the benefits of vegetation coverage to sediment reduction are particularly affected by rainfall intensity. If you want to get an ideal effect of erosion reduction, the greater rainfall intensity must be corresponding higher vegetation coverage.3) By regression analysis. Pisha sandstone slope erosion sediment shows a good linear relationship with slope and vegetation coverage, and has a good power function relationship with the rainfall intensity. Then water erosion forecast model about Pisha sandstone slope is established with time, rainfall intensity, slope, and vegetation coverage.4) After spraying W-OH, a steady and solidification layer is formed on the Pisha sandstone surface, which could play a role in isolation of water and Pisha sandstone and speed up the flow grooming by improving slope smoothness. Indoor rainfall conditions, erosion reduction of W-OH has a significant effect, and the sediment reduction rate under different conditions is more than 98%. The same to outdoor conditions, the sediment reduction rate is even more than 99.5% in two types of slope.更多还原