The Evaluation of the Hydrogeological Parameters of a Field Pumping Test within Multi-layer Unconfined Pebble Aquifers: A Case Study

This paper presents a case study of field pumping tests and the evaluation of the hydrogeological parameters of the unconfined pebble aquifers in the test site located at Shijiawan station in Luoyang City, China, which guarantees the construction safety of Metro Line 1. Multiple groups of single-well pumping tests and one group-well pumping test were conducted to obtain the aquifers’ hydrogeological parameters. Then, a combination of theoretical analysis and numerical simulation was used to evaluate the aquifers’ hydrogeological parameters. The analytical solutions were obtained for the unconfined, anisotropic pebble aquifers using the Neuman model. The numerical simulation was established via the finite element method (FEM). The calculation results indicate that the theoretical analysis and numerical simulation parameters are well matched. Moreover, the results of the numerical method which considers the heterogeneous and horizontal isotropic characteristics of the pebble stratum, as well as the hydrogeological parameters are more reliable than the results obtained by the theoretical analysis. The pumping tests also indicate that the supporting structure plays a significant role in waterproofing during dewatering construction.