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CN-116465597-B - Experimental device and method for monitoring thickness of capillary band

CN116465597BCN 116465597 BCN116465597 BCN 116465597BCN-116465597-B

Abstract

The invention relates to an experimental device and method for monitoring Mao Xidai thickness, wherein the device comprises a sand column and a water level regulating mechanism, a baffle plate is arranged in the sand column, a sand column water inlet and a sand column water outlet are arranged on the sand column, a plurality of pressure water head monitoring holes and a plurality of water content monitoring holes are arranged on the sand column, a water level regulating unit comprises a container, a container water inlet, a container water outlet and a sand column water supply port connected with the sand column water inlet through a pipeline are arranged on the container, the device can be used for measuring the maximum capillary rising height of different soils through a drainage experiment, and the device can be used for observing the dynamic change of a non-saturated zone soil water section along with the fluctuation of an underground water level through the driving of an external periodic water head because the drainage of the sand soil is not instant and can be used for researching the influence of the water level of inland river water level on the underground water level fluctuation and the interaction of underground water and sea areas.

Inventors

  • Mu Haokun
  • LIANG XIUYU

Assignees

  • 南方科技大学

Dates

Publication Date
20260512
Application Date
20230418

Claims (8)

  1. 1. The experimental method for monitoring the thickness of the capillary band is based on an experimental device for monitoring Mao Xidai the thickness, and is characterized by comprising a sand column and a water level adjusting mechanism for adjusting the water level in the sand column, wherein a partition plate capable of allowing water to pass through and blocking sandy soil is arranged in the sand column, and the partition plate divides the inner space of the sand column into a sand-containing seepage area positioned at the upper part and a water storage area positioned at the lower part; A sand column water inlet with a valve for feeding water to the water storage area and a sand column water outlet with a valve for discharging water to the water storage area are arranged on the sand column; The sand column is provided with a plurality of pressure water head monitoring holes with different heights for monitoring the pressure water head and a plurality of water content monitoring holes with different heights for monitoring the water content; the water level regulating unit comprises a container, and a container water inlet, a container water outlet and a sand column water feeding mouth connected with the sand column water inlet through a pipeline are arranged on the container; the experimental method adopts any one of the first method and the second method; the method comprises the following steps: according to the water level elevation required by the experiment, the height position of the sand column is adjusted, and the height position of the inner bottom of the container is adjusted to be consistent with the required water level in the sand column; The sand column water outlet keeps a closed state, water is fed into the container, and water enters the sand column through the pipeline and the sand column water inlet; Stopping water inflow to the container after the water level in the sand column reaches the required water level, adding sand and soil medium into the sand-filling seepage area of the sand column, naturally settling the sand and soil to the bottom along with water, wherein the water-containing medium layer is required to be smaller than the water level; Connecting a pressure water head measuring instrument with a pressure water head monitoring hole, connecting a water content measuring instrument with a water content monitoring hole, and closing a sand column water inlet after the indication is stable; recording the height of the water level in the sand column and the thickness of the water-bearing layer medium, and then taking a certain amount of water from the sand column water outlet at intervals and recording; repeating the previous step until the water level is reduced below the medium surface elevation, and then sampling for a plurality of times; obtaining the maximum capillary rising height and water supply degree of the sandy soil medium according to the linear correlation relation between the pressure water head monitoring hole and the water content monitoring hole and the summation of corresponding water intake respectively in the sampling process; the second method is as follows: according to the water level elevation required by the experiment, the height position of the sand column is adjusted, and the height position of the inner bottom of the container is adjusted to be consistent with the required water level in the sand column; The sand column water outlet keeps a closed state, water is fed into the container, and water enters the sand column through the pipeline and the sand column water inlet; Stopping water inflow to the container after the water level in the sand column reaches the required water level, adding sand and soil medium into the sand-filling seepage area of the sand column, naturally settling the sand and soil to the bottom along with water, wherein the water-containing medium layer is required to be smaller than the water level; Connecting a pressure water head measuring instrument with the pressure water head monitoring hole, and connecting a water content measuring instrument with the water content monitoring hole; Lifting and adjusting the height position of the sand column, and switching the drainage and wetting states of the internal sand, wherein the interval between the drainage process and the wetting process is not less than a set duration; And continuously recording data of the pressure water head monitoring hole and the water content monitoring hole in the process of changing the water level in the sand column from the lowest position to the initial position.
  2. 2. An experimental method for monitoring Mao Xidai a thickness according to claim 1, wherein the container is provided with a partition member dividing the container into two transversely-distributed compartments, one of the two compartments is provided with the container water inlet and the sand column water supply mouth, the other is provided with the container water outlet, and the upper parts of the two compartments are communicated, and the height of the communicated position is lower than the lowest height of the opening of the container.
  3. 3. An experimental method for monitoring Mao Xidai thickness according to claim 1, further comprising a Z-axis displacement platform for elevating the sand column.
  4. 4. An experimental method for monitoring Mao Xidai thickness according to claim 1, wherein said separator is provided with one or more through holes and a gauze covering said through holes.
  5. 5. An experimental method for monitoring Mao Xidai thickness according to claim 1, wherein the pressure head monitoring orifice is connected to a pressure head meter.
  6. 6. An experimental method for monitoring Mao Xidai thickness according to claim 1, wherein the water content monitoring hole is connected with a water content detector.
  7. 7. An experimental method for monitoring Mao Xidai a thickness according to any one of claims 1-6, wherein a plurality of said pressure head monitoring holes are distributed linearly over said sand column.
  8. 8. An experimental method for monitoring the thickness of Mao Xidai according to any one of claims 1 to 6, wherein a plurality of said water cut monitoring holes are linearly distributed on said sand column.

Description

Experimental device and method for monitoring thickness of capillary band Technical Field The invention relates to the technical field of water pollution control, in particular to an experimental device and method for monitoring the thickness of a capillary band. Background At present, related researchers find that capillary bands have non-negligible effects in groundwater hydraulic transmission and solute transport, and the presence of capillary bands can cause fluctuations in groundwater level and migration of contaminants between saturated and unsaturated bands, which are quite different compared to conventional models and understanding. Thus, the related studies of the capillary band have become a hot spot problem. However, the content research on the upper boundary definition of capillary band, the measurement of capillary band thickness, the variation of capillary band thickness with groundwater level and the like is not very perfect. Mao Xidai thickness and thickness variations with groundwater level are difficult to measure and therefore require a related device to assist in research. Indoor sand column equipment is always one of the indispensable equipment for hydrodynamic experiments and water pollution experiments. The water content of the unsaturated zone has hysteresis, and the characteristic of the unsaturated zone is different from the characteristic of the pressure water head of the saturated zone, so that the consideration of the parameter changes of the saturated zone and the unsaturated zone in the process of the underground water level fluctuation is very meaningful. The traditional sand column experiment mainly observes the change of the groundwater level, and although the water content is observed, the research on the dynamic change of the capillary band thickness along with the groundwater level of the whole soil section is relatively less. Therefore, the invention designs an experimental device and a method for monitoring the thickness of the capillary band, so as to meet the requirements of the field. Disclosure of Invention The invention aims to solve the technical problems by providing an experimental device for monitoring the thickness of capillary strips and a research method for monitoring the dynamic thickness change of capillary strips and the maximum capillary rise by using the device. The technical scheme adopted for solving the technical problems is as follows: an experimental device for monitoring the thickness of a capillary band is constructed, wherein the experimental device comprises a sand column and a water level adjusting mechanism for adjusting the water level in the sand column, a baffle plate which can enable water to pass through and block sand is arranged in the sand column, and the baffle plate divides the inner space of the sand column into a sand-filling seepage area positioned at the upper part and a water storage area positioned at the lower part; A sand column water inlet with a valve for feeding water to the water storage area and a sand column water outlet with a valve for discharging water to the water storage area are arranged on the sand column; The sand column is provided with a plurality of pressure water head monitoring holes with different heights for monitoring the pressure water head and a plurality of water content monitoring holes with different heights for monitoring the water content; the water level regulating unit comprises a container, and a container water inlet, a container water outlet and a sand column water feeding mouth connected with the sand column water inlet through a pipeline are arranged on the container. The experimental device for monitoring Mao Xidai thickness comprises a container, a partition piece, two compartments, a water inlet of the container, a water feeding mouth of a sand column, a water outlet of the container, and a lower connecting part, wherein the container is provided with the partition piece, the partition piece divides the container into two compartments which are transversely distributed, one of the two compartments is provided with the water inlet of the container and the water feeding mouth of the sand column, the other one of the two compartments is provided with the water outlet of the container, and the upper parts of the two compartments are communicated with each other, and the height of the communicating part is lower than the lowest height of an opening of the container. The invention discloses an experimental device for monitoring Mao Xidai thickness, wherein the device also comprises a Z-axis displacement platform for driving the sand column to lift. The experimental device for monitoring Mao Xidai thickness provided by the invention is characterized in that one or more through holes and a gauze covering the through holes are arranged on the partition plate. The invention discloses an experimental device for monitoring Mao Xidai thickness, wherein a pressure water head monitoring hole is conn