Effect of Global Warming on the Dissolution of Limestone

抄録

The effect of global warming on the dissolution of limestone was observed by using numerical simulation. The examination is related to the stability of the underground dam constructed in the south islands in Japan. The model includes dispersion/diffusion, advection, ion exchange, formation of complexes in the aqueous phase, and the dissociation of water and chemical precipitation. The mass action, transport, and the site action equations are expressed in a differential/algebraic form and solved simultaneously by FEM. Results revealed that the physical effect of global warming was very small but considering the detailed investigation of each parameter, lowering of pH has greatest influence on dissolution of limestone, followed by increase in temperature. As the acidification of the rain water progresses, the dissolution of limestone increases. As a result, underground soil porosity increases so that more water will be stored in the aquifer. Increase of intensity of rain, which coincides with the increase of velocity of inlet water, caused the decrease in the dissolution of limestone compared to reference. Dissolution of limestone was favored with increasing temperature as a result porosity of underground dam also increased. Dissolution of limestone increased with combined change of pH, velocity and temperature so that porosity also increased.