Assembled-type vertical saturated soil column pollutant migration testing device

Abstract

The invention relates to an assembled-type vertical saturated soil column pollutant migration testing device. The device comprises a test soil column and a water supplying device, wherein the test soil column is formed by assembling three types of basic components, namely, an upper water feeding component, middle sample loading components and a lower water discharging component, which are connected with one another by virtue of flanges which are arranged on the basic components; the middle sample loading components are staggered according to a certain angle and then are connected with one another; the upper water feeding component comprises a shell, an inner core and a porous stone; a water discharging outlet is formed in the bottom of the shell so as to reduce errors caused by replacement of a solution; the inner core comprises an upper turbulent flow layer and a lower helix mixing layer and is used for promoting solutions at the upper part to be evenly mixed; the porous stone is put on the top of a soil layer after sample loading is finished; each middle sample loading component can be split into two arc-shaped tube materials, water blocking rings are arranged in each arc-shaped tube material at intervals so as to prevent water flow from being cut off; and a porous stone is contained in the lower water discharging component. As the testing device is applied, a testing condition is optimized so as to reduce testing errors, and the testing device can adapt to simulation tests of multiple lengths by assembling the components of different numbers and specifications, so that the model utilization rate is improved and the cost is reduced. Thus, the mass production of the device can be realized.

Description

technical field [0001] The invention relates to a soil and groundwater pollutant migration test simulation device, in particular to a pollutant migration test in a vertical saturated soil column. technical background [0002] In recent years, with the rapid development of the national economy, the domestic environment has been damaged to a certain extent, and the water resource environment has also been seriously polluted. With the aggravation of the pollution of surface fresh water resources, the problem of groundwater pollution will become increasingly prominent. Therefore, it is very important to study the migration rules and influencing factors of pollutants in soil and groundwater. It will contribute to the control of groundwater pollutants, as well as the prediction and assessment of pollution conditions. The vertical saturated soil column test model is an important means to study the migration of pollutants in soil and groundwater at home and abroad. Through this mod...

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Problems solved by technology

[0003] At present, the vertical saturated soil column model used in the laboratory is relatively simple, and the principle is basically the same, but there are three problems in the actual use process: model error system problem, soil sample collection problem and model utilization repetition rate problem

Part of the leaching tests use showers or direct drip water supply, different soil columns have different permeability, and the thickness of the water retained at the top is also unstable, which cannot provide stable water supply for the soil column, and it is also difficult to use the conditions of large water head. Makes the test time longer and less efficient

[0006] (2) The uneven spatial distribution of the upper boundary concentration

None of the existing models consider the spatial difference of the upper boundary concentration, but due to the boundary effect, in the same plane, the migration rate of pollutants in the center and the surrounding boundary is different, resulting in the spatial difference of the upper boundary concentration; in addition, the present Some water supply methods (whether it is open dripping or closed injection) lead to a certain flow velocity of the injected solution, and the uneven spatial distribution of the flow velocity (large in the middle and small around) also leads to uneven spatial distribution of the upper boundary concentration; Furthermore, there are spatial differences in the permeability coefficient and diffusivity of the soil column itself, which will also lead to the same problem

[0007] (3) The upper boundary solution replacement problem

If the original solution is not discharged, when the pollutant solution is directly added, the mixture of the two will cause the initial concentration of the upper boundary to be lower than the expected concentration, making the test progress slowly, which will greatly affect the follow-up test and cause a large system error.

[0008] (4) Short circuit problem of water flow on the inner wall of the model

The inner wall of the existing model is relatively straight, and some models will be frosted, but the effect is not obvious, and it is still possible for the solution to flow easily on the inner wall, causing a large error in the model

[0009] The second aspect is the problem of soil sample collection

Since the existing models do not have fixed specifications, or are not segmented, they cannot adapt to a variety of tests of different lengths or depths, and the model reuse rate is low

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