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用人工渗灌的方法使粉砂土排水地段的地下水位升至地表,然后在两排水渠之间选定的地点加入 KI~(131)溶液用闪烁计数器观测在不同时间放射性同位素的传播情况。根据观测结果绘制放射性的等量线图。可知在施同位素两周后放射强度的最大残存量是在最初灌入 KI~(131)溶液的地点。加入同位素后几分钟,不但在垂直方向而且在排水管方向的一米远处,都发现了少量放射性。放射性的移动主要是向下的,并且严格遵守时间对数和距离的比例关系,据此可以算得水流的最小速度。土壤物理性质对放射性传布的影响用一个比例常数来表示,除此定量结果外,通过对等量线的研究也可得出如下结论:1、向排水管的流线穿过底土深达2米以上;2、过去因埋设排水管经过翻动的土壤,较未扰动土显示出更大的通透性,这说明机械耕作的影响纵然在十多年后仍然存在;3、在不同结构的土壤的界面垂直水流受到阻碍,即使下一层土壤有较大的通透性也是如此。
The method of artificial seepage was used to raise the groundwater level of the silt gully drainage area to the surface. Then KI 131 solution was added at selected locations between the two drainage channels to observe the radioactive isotope propagation at different times using a scintillation counter. Draw a radioactive isometric plot based on the observations. It is known that the maximum level of radioactivity after two weeks of isotope application is at the point where KI ~ (131) solution was initially poured. A few minutes after adding the isotope, a small amount of radioactivity was found not only in the vertical direction but also one meter in the direction of the drain. Radioactive movement is mainly downward, and strictly abide by the logarithm of the ratio of time and distance, which can be calculated as the minimum speed of water flow. In addition to the quantitative results, through the study of equivalent lines, the following conclusions can be drawn from the influence of soil physical properties on the distribution of radioactive emissions: 1, the flow line to the drainage pipe penetrates through the subsoil to a depth of 2 meters Or above; 2. In the past, the soil that had been drained through the drainage pipes showed greater permeability than the undisturbed soil, indicating that the influence of mechanical farming was still present even after more than 10 years; 3. In the soil with different structures The vertical flow of the interface is hampered, even with the greater permeability of the next layer of soil.