摘要
在有钙华沉积的云南白水台景区引水渠道中,通过水准测量以及导线测量的方法,获得了引水渠道各研究点的相对高程和距离。利用流速仪测定了各研究点的水流流速,通过计算获得了各研究点的总水头和水力坡度。利用水化学记录仪,在短时间内测定了各研究点的电导率、水温与pH值,结合现场滴定以及室内水样分析的结果,计算出各点的方解石饱和指数和二氧化碳分压。发现在方解石饱和指数大于0.8的研究渠段,电导率、Ca2+和HCO3-浓度沿水流方向降低,经成因分析与数学推导,得出Ca2+浓度与总水头呈线性关系,水力坡度与渠段上的钙华沉积量也呈线性关系,这是岩溶作用动力学扩散边界层控制理论的具体体现,也即水力坡度越大,流速越快,扩散边界层越薄,碳酸钙沉积速率越大。
Methods of leveling survey and traverse survey were used to measure the relative elevation and distance between sampling sites in the travertine-depositing canal in the Baishuitai scenic area, Yunnan Province. A flow meter was used to measure the flow velocity at each sampling site and the data of total head and hydraulic gradient at the sampling sites were obtained by calculation. The calcite saturation index and carbon dioxide partial pressure were calculated by using a method that combined electrical conductivity, water temperature and pH （which were recorded during a short time by hydrochemical data logger） with the in-situ titration and laboratory measurements of water samples. It was found that the electrical conductivity and the concentrations of Ca^2＋ and HCO2- decreased downstream of the canal where the calcite saturation indices of water were greater than 0.8. It was also found from genetic analysis and mathematical derivation that there existing linear relationships between the concentrations of Ca^2＋ and the total head and between the amount of deposited travertine and the hydraulic gradient in the canal. This phenomenon is just a reflection of the theory of diffusion boundary layer that controls karst kinetics, i. e. , the higher the hydraulic gradient, the higher the flow speed, the thinner the diffusion boundary layer, and the higher the calcite deposition rate.
出处
《地球与环境》
CAS
CSCD
北大核心
2009年第2期103-110,共8页
Earth and Environment
基金
国家自然科学基金(40572107)
中国科学院"百人计划"项目
国家社会公益项目(2005DIB3J067)资助
关键词
溪流
钙华沉积
总水头
水力坡度
流速
扩散边界层
云南白水台
stream
travertine deposition
total head
hydraulic gradient
flow velocity
diffusion boundary layer
Baishuitai, Yunan Province
