岩溶地区生态防排水技术研究

发布时间：2018-08-21 19:49

【摘要】：中国作为世界上拥有岩溶很多的国家,它的岩溶总面积接近363万km2,占国土面积的1/3,并且岩溶地貌具有分布广泛、面积大的特点。而岩溶地区的水环境相当脆弱,在岩溶地区进行公路建设很容易造成水环境破坏,一旦破坏,很难恢复。不合理的经济活动将会使该地区的很多地方水土流失十分严重,各种灾害发生频繁,从而阻碍了岩溶区国民经济的发展。本文旨在研究岩溶地区公路排水与生态环境保护相协调,合理设计、满足生态保护要求的排水系统,保护公路沿线的植被和水环境。考虑到岩溶地区脆弱的生态环境,在该地区进行工程建设时尽量减少开挖量,保持原有的生态平衡,本文进一步提出了浅碟形植草边沟。然而影响浅碟形植草边沟过水能力的有过水断面的面积、边沟的底坡坡度,还有边沟的壁面粗糙系数。但对给定的明渠均匀流来说,粗糙系数的变化影响着渠道的排水能力。通过室内模型试验研究生态植草边沟内的水流特性,对5组不同流量下的植草边沟与非植草边沟进行了较为系统的研究,然后通过试验数据结合水力学分析,结果表明:植草边沟内的水流在缓流情况下,其粗糙系数为0.03。同时,边沟内的植草在很大程度上改变了原来水流的内部结构,较混凝土边沟的沟渠糙率增大,流速减小,水位升高,水力半径增大。边沟粗糙系数也随着其它水力要素间的改变而变化,并不为常数。流量的增大会引起粗糙系数减小。随着表征水流状态的雷诺数和佛汝德数的增加,粗糙系数呈现一个下降的趋势,且与佛汝德数之间拟合公式的相关系数为0.9974,表明拟合关系很好。根据室内生态边沟模型试验分析,加之岩溶地区这种特殊的地质概况,结合岩溶地区公路生态排水的设计的原则,提出适合岩溶地区生态排水的设计参数,为以后在岩溶地区进行类似的工程建设提供一定的参考价值。
[Abstract]:As a country with a lot of karst in the world, China has a total karst area of nearly 3.63 million km ~ 2, accounting for one third of the land area, and the karst geomorphology has the characteristics of wide distribution and large area. However, the water environment in karst area is very fragile, it is easy to cause water environment damage by highway construction in karst area, once destroyed, it is difficult to recover. Unreasonable economic activities will cause serious soil and water loss and frequent disasters in many places in this area, thus hindering the development of national economy in karst area. The purpose of this paper is to study the drainage system of highway in karst area, which is coordinated with ecological environment protection, reasonably designed to meet the requirements of ecological protection, and protects the vegetation and water environment along the highway. In view of the fragile ecological environment in karst area, the excavation amount is reduced and the original ecological balance is maintained during the engineering construction in this area. However, the area of the cross section, the slope of the bottom slope and the roughness coefficient of the wall of the edge ditch affect the water passing ability of the edge ditch. But for a given open channel uniform flow, the variation of roughness coefficient affects the drainage capacity of the channel. Through the indoor model test to study the characteristics of water flow in the edge ditch of ecological grass planting, five groups of grass edge ditch and non-planting edge ditch under different flow rate were studied systematically, and then the test data were combined with hydraulic analysis. The results show that the rough coefficient of the flow in the furrow is 0.03 under the condition of slow flow. At the same time, the grass planting in the edge ditch changed the internal structure of the original flow to a great extent, which increased the roughness, decreased the velocity, increased the water level and increased the hydraulic radius compared with the concrete side ditch. The roughness coefficient of edge trenches varies with the change of other hydraulic factors and is not constant. The roughness coefficient decreases with the increase of flow rate. With the increase of Reynolds number and Froude number, the rough coefficient shows a downward trend, and the correlation coefficient between the fitting formula and the Froude number is 0.9974, which indicates that the fitting relationship is good. According to the indoor ecological side ditch model test and the special geological situation in karst area, combined with the design principle of highway ecological drainage in karst area, the design parameters suitable for ecological drainage in karst area are put forward. It provides some reference value for similar engineering construction in karst area.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U417.3

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