关键词: 滨海地区, 地下咸水, 储能回灌, 胶体释放, 渗透性变异

Abstract:

In order to reveal the mechanism of permeability variation of the aquifer in the process of the saline water energy storage with recharging in Tianjin coastal area, laboratory column experiments were conducted to investigate the capability and rate of colloid release at different temperatures, the effect of colloid release on the permeability of the aquifer, and the change characteristics of Ca2+ during colloid release. The research results show that the colloid release from saline aquifer water-bearing media is pulse type, and presents to increase suddenly and decrease slowly with the period of 20 pore volumes in the saline water energy storage recharging process. The cumulative release capacity of colloids from saline aquifer increases with increasing pore volumes; and the release dynamic curve of colloid is segmental straight-line, and release rate and growth range of colloid is decreased. The permeability of the aquifer varies in the process of colloid release. The permeability coefficient of the saline aquifer shows a curve of “S” type with increasing pore volumes. In the condition of 0℃,10℃ and 20℃, the permeability coefficient increass by 4.02, 12.21 and 6.63 times respectively. Although the initial permeability coefficients of the saline aquifer vary at different temperatures, and increases gradually to reach about 15 cm/d after 60 pore volumes. Ion exchange reactions of Ca2+ with K+, Na+ exist in the process of colloid release; but the dynamic features of the reactions change with temperatures.

Key words: coastal area, saline groundwater, recharge of energy storage, colloid release, permeability variation