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本工作测定了土壤包气层中 3 H和 90 Sr在天然条件和人工喷淋条件下的扩散系数 ,并研究了 3 H和 90 Sr示踪剂在黄土包气层中的迁移行为。结果表明 ,在华北地区黄土高原天然条件下 ,包气层中氚示踪剂以 0 .0 3cm/d速度迁移 ,纵向扩散系数 Dx 为 0 .5 2 cm2 /d;在 2 m× 2 m实验坑中 ,以 5 mm/h喷淋强度每天喷淋 3h的条件下 ,氚示踪剂以 2 .2 7cm/d的速度向下迁移 ,纵向扩散系数 Dx 为 7.75cm2 /d。包气层中天然条件下 90 Sr基本没有迁移 ;人工喷淋条件下 ,90 Sr以 3.7× 10 -3 cm/d速度迁移 ,纵向扩散系数 Dx 为 0 .0 3m2 /d
In this work, the diffusion coefficients of 3 H and 90 Sr in natural gas and artificial sprinkler were measured, and the migration of 3 H and 90 Sr tracer in loess gas-bearing layer was studied. The results show that the tritium tracer migrates at a rate of 0. 03 cm / d and the longitudinal diffusion coefficient Dx is 0.52 cm2 / d under the natural conditions in the Loess Plateau of North China. In the 2 m × 2 m experiment In the pit, the tritium tracer migrated downward at a rate of 2.27 cm / d and the vertical diffusion coefficient (Dx) was 7.75 cm 2 / d under the condition of 5 mm / h showering intensity spraying for 3 h per day. 90 Sr basically did not migrate under natural conditions in the gas-bearing layer. Under the condition of artificial sprinkling, 90 Sr migrated at a velocity of 3.7 × 10 -3 cm / d and the longitudinal diffusion coefficient Dx was 0.30 m 2 / d