落水洞对裂隙-管道介质泉流量衰减过程影响的试验研究

Experimental study on the effects of sinkholes on spring flow attenuation process within fissure-conduit media

岩溶裂隙-管道是我国西南地区的主要地下储水空间和导水通道,落水洞是岩溶地区临时性吸收地表水流的重要过水通道,在西南地区分布密集。开展落水洞大小对裂隙-管道介质中泉流量过程影响的研究,对指导岩溶水可持续开发利用和推动岩溶水研究具有深刻意义。文章研究了落水洞对泉流量衰减过程的影响,利用自制的裂隙-管道物理模型,模拟落水洞不同断面尺寸、填充程度下的泉流量衰减过程,由衰减曲线探求衰减系数受不同因子的敏感程度。试验表明:泉流量衰减过程可分为三个亚动态,大致符合指数型衰减。其中,第一亚动态的衰减系数受落水洞断面尺寸影响较大,落水洞断面尺寸越小,衰减系数越大;落水洞的填充程度越高,衰减系数越大。

The karstic fissures and conduits are the main underground water-storing space and water-conducting channels in Southwest China. Sinkholes are important water discharge channels for temporary storage of the surface water in karst area, and are widely distributed in the Southwest. To study the effects of sinkholes on the spring flow attenuation process is of great importance to the sustainable development and the study of the karst hydrology. A physical model of fissure-conduit medium was set up in this study, and was used to simulate the spring flow attenuation process in sinkholes of different sizes and degrees of filling. The sensitivity of the attenuation coefficient to different factors was explored with the attenuation curve. Results of the experiments demonstrated that the exponential attenuation formulation can describe the attenuation process generally, and the attenuation curve can be divided into three phases. The attenuation coefficient of the first phase is much subject to the size of the sinkhole. The attenuation coefficient will increase as the sinkhole size decreases, and it has positive correlation with the degree of filling of sinkholes.