地下水位抬升对人工回灌中悬浮物堵塞的影响

为了研究人工回灌条件下地下水位抬升对悬浮颗粒在含水层中的迁移-沉积的影响机理,在室内模拟实验中,采用100 mg/L的金刚砂悬浊水回灌中粒石英砂介质,分别研究了不同抬升速率(0、2、4cm/h)条件下人工回灌过程中的悬浮物堵塞规律。实验结果表明:地下水位抬升速率对堵塞位置和堵塞位置处悬浮物的级配影响不大,悬浮物主要淤积在0~2cm深度处;在26h前地下水位抬升引起的入渗量比地下水位固定的入渗量小,在26h后二者相反;水位抬升使介质表层堵塞发展速度减慢,非堵塞层渗流状态出现非饱和时刻滞后;在堵塞层0~2cm处地下水位抬升使堵塞速率小于地下水位固定的堵塞速率。

Impact of Groundwater Level Rising on Suspended Solids Clogging During Artificial Recharge

In order to study groundwater level (GL) rising impacts on suspended particle migration and deposition in porous media during artifical recharge of groundwater,three compared sand column experiments were conducted indoor using aritfical recharge water with suspended solids of 100 mg/L under three GL rising rates (0,2,4 cm/h).The results show that ground water level rise rate has little or no effect on the clogging position and the size of suspended solids at the clogging position.Most of the suspended solids deposit in the depth of 0 to 2 cm.While the clogging time characteristics varies observably with different GL rising rats.In the first 26 h,the infiltration rate under rising GL is smaller than that of constant,while it turned opposite after 26 h.The reason is that the total hydraulic head pressure difference decreases with GL rising for the early period,and when the clogging clayer developed to a certain degree (after 26 h),the seepage state of the non-blocking zone beneath clogging layer appears unsaturated,and infiltration capacity of the clogging layer controls the infiltration rate.Since the clogging rate of the main clogging layer of 0 to 2 cm is smaller under GL rising scenarios,the infiltration rate can still be maintained at a relative high value and occurrence of unsaturated infiltration state delayed as well.