河床水力传导度及其各向异性的测定

采用直接测定法观测了黑河中游段河床水力传导度及其各向异性,结果表明:河床水力传导度不仅存在较强的各向异性,而且存在空间尺度上的变异性.河床中心位置在垂直、水平和θ=30°方向的平均水力传导度分别为0.45、22.49和1.71 m/d,河床边分别为5.95、29.69、16.80 m/d.在同一测点,水力传导度随着与水平方向的夹角增大呈幂函数曲线下降.试验结果表明河床边是河水的主要渗漏区,并且以侧渗为主.

Measurement of streambed hydraulic conductivity and anisotropy analysis

The hydraulic conductivity between stream and adjacent aquifers is an important issue for water resource management.The hydraulic conductivity of the streambed is an essential variable in determining the hydraulic connection between a stream and adjoining aquifers.The paper applies straight and L-shaped standpipes directly to streambeds for measuring the in-situ hydraulic conductivity in the vertical(k_v) and horizontal(k_h) directions,as well as in other oblique directions(k_s) in the middle reaches of Heihe river.Results indicate that the hydraulic conductivity of streambed has not only significant anisotropy,but also variability at the spatial scale.In the same measured spot,the hydraulic conductivity decreases with the increase of the angle between horizontal and measurea direction(θ).At the spatial scale,the hydraulic conductivity of side streambed is higher than that of the middle streambed,especially in the vertical direction This indicates that the side streambed is an important leakage region.