Water Science and Engineering (2019-06-01)

Porosity and permeability variations of a dam curtain during dissolution

  • Ji-xiang Huo,
  • Fu-heng Ma,
  • Xiao-lei Ji

Journal volume & issue
Vol. 12, no. 2
pp. 155 – 161

Abstract

Read online

During reservoir operation, the erosion effects of groundwater change the porosity and permeability of the dam curtain, causing changes to the seepage field. To understand where the changes take place and to what degree the porosity and permeability change, a multi-field coupling model was built and solved. The model takes into account seepage, solution concentration, and solid structure. The model was validated using uplift pressure monitoring data. Then, the variations in curtain porosity, seepage flow, and loss quantity of Ca(OH)2 were calculated. The key time nodes were obtained through curve fitting of the variation of seepage flow with the BiDoseResp function. The results showed that the model could reflect the attenuation trend of curtain performance well. The process and position of the erosion were not homogeneous. Although erosion mainly occurred at the top and bottom of the curtain, it was most developed at the top. The erosion effects developed slowly during the early stage, much fast during the middle and late stages, and culminated in complete dissolution. The model results and the daily monitoring data can provide a scientific basis for the safe operation and management of reservoirs. Keywords: Dam curtain, Permeability, Multi-field coupling model, Porosity, Erosion, Solute transport, Seepage flow