双向低频振动对铀尾矿库滩面覆土层控氡效果影响的试验研究

双向低频振动引起铀尾矿库滩面覆盖层控氡效果劣化是其结构设计中应加以考虑的一项问题。以铀尾砂与本地红土为原材料,制备干燥、自然和饱和三种含水状态下铀尾矿库滩面覆土层试样,基于自制激振组合氡析出试验装置,开展双向低频振动下铀尾矿库滩面覆土层氡析出试验。结果表明,不同含水状态的铀尾矿库滩面覆土层在低频振动条件下,均大致呈现降氡效率随覆土厚度增加而增加的趋势,其中当覆土厚度为5 cm时,降氡效率分别为54.14%、50.32%、60.51%;当激振频率为10 Hz左右时,干燥、自然状态覆土表面氡析出率均达到峰值,分别为0.135 Bq/(m²·s)、0.089 Bq/(m²·s),而饱和状态覆土表面氡析出率在15 Hz的低频振动条件下达到峰值0.118 Bq/(m²·s);双向低频振动对覆土层控氡效果的影响程度表现为:饱和状态>干燥状态>自然状态。

Experimental Study on Effect of Double Directions Low-frequency Vibration on Soil-covering Layer Radon Reduction of Uranium Tailings Pond Beach

Double directions low-frequency vibration should degrade the soil-covering layer effectiveness of radon reduction for uranium tailings pond beach, so structural design of the layer is one of the issues to be considered. In this study, uranium tailings and local laterite have been chosen as the raw materials for the preparation of the samples of soil-covering layer for uranium tailings pond with three water content, namely dry, natural and saturated cases. The experiment of surface radon exhalation from those cases under the condition of double directions low-frequency vibration with different frequencies have been carried out by utilization of self-made experimental installation. The results show that radon reduction efficiency for each case mainly exhibits positive correlation with the height of soil-covering layer, especially when the height is 5 cm, the radon reduction efficiencies are 54.14%, 50.32% and 60.51%, respectively; when the vibration frequency is 10 Hz, radon exhalation rates for dry and natural cases reach peak values, i.e. 0.135 Bq/(m²·s) and 0.089 Bq/(m²·s), respectively; however, the peak value of 0.118 Bq/(m²·s) for saturated case has been found with the vibration frequency of 15 Hz; the influence levels of double directions low-frequency vibration on radon reduction are shown as this relationship:saturated case >dry case> natural case.