Karst conduit hydro-gradient nonlinear variation feature study: case study of Zhaidi karst underground river

摘要

Through the analysis of monitoring data with a time interval of 10 min during the rainy season of 2012, for three points of G37, zk8 and zk7 which are located on the main conduit of Zhaidi karst underground river system, the variation features of water level and hydraulic gradient are studied and the relations are established between gradient and water level or amplitude. (1) It is first discovered that there are different function relations such as linear, parabola and inverse parabola between the G37's water level and the hydraulic gradients of different conduit part. (2) The peak delay times for water level curves are < 50 min and the maximum conducting speed of water press is faster than 13,020 m/h. (3) The upstream and downstream karst conduits have corresponding enlarging and shrinking amplitude function by the coefficients of 1.899/km and 0.125/km. (4) The gradient I variation is still linear to the level difference Delta H made by nine rainstorms. The conclusion and the methods of this paper have significance on the study of the regulation and storage capacity and groundwater resources evaluation of karst underground-river system.