A method for preventing cross-zone sampling of a groundwater sampling well

Abstract

The present application belongs to the technical field of groundwater sampling, and particularly relates to a method for preventing layer mixing during groundwater sampling in a water well, comprising the following steps: injecting clean water into the sampling water well and flushing the well wall, and then pumping out the mixed water at the bottom of the sampling water well; setting a blocking device in the sampling water well to intercept the seepage water above the sampling layer; setting a water collector below the blocking device in the sampling water well, with the tube mouth of the water collector leaning against the well wall to collect the seepage water; after sampling is completed, the tube mouth of the water collector is closed, the blocking device is removed, and the water collector is recovered to complete the sampling. By means of the blocking device, the seepage water above the sampling layer is guided away along the blocking device, so that the water collected from the sampling layer is relatively accurate, and layer mixing is avoided. By means of the water collector leaning against the well wall to collect water, insertion into the well wall is avoided, the content of silt in the sampled water is reduced, and the water collector and the water pump can be prevented from being blocked.

Description

Technical Field

[0001] This invention belongs to the field of groundwater sampling technology, specifically relating to a groundwater sampling well anti-cross-layer sampling method. Background Technology

[0002] When monitoring groundwater, it is necessary to drill wells to form sampling wells. Especially when sampling shallow water, since the water mainly comes from precipitation and surface runoff, and the soil and gravel have a certain filtering effect, the pollution status of water bodies at different depths is not the same.

[0003] Currently, water samples are taken through sampling wells. However, because water seeps through the well walls and accumulates inside the well, the samples collected inside the well are mixed water bodies after cross-layering, and cannot effectively reflect the water quality of a specific water layer. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a groundwater sampling well anti-cross-layer sampling method, which can avoid cross-layering of water samples obtained in the sampling well and improve the detection accuracy.

[0005] The specific technical solution adopted in this invention is as follows: A groundwater sampling well anti-cross-layer sampling method includes the following steps: S1. Pour clean water into the sampling well and rinse the well wall, then pump out the mixed water from the bottom of the sampling well; S2. Install a blocking device inside the sampling well to intercept the seepage water above the sampling layer; S3. A water sampler is installed in the sampling well below the blocking device. The water sampler is located at the bottom of the sampling layer, and the pipe opening of the water sampler rests against the well wall to collect seepage water. S4. After sampling is completed, the inlet of the water sampler is sealed, the blocking device is removed, and the water sampler is retrieved to complete the sampling.

[0006] In step S2, after the blocking device is set up, wait 1.5-2 hours before opening the water sampler's port to collect samples.

[0007] The blocking device includes a traction main cable, a water intake core tube, and an expansion bladder arranged in a U-shape around the outside of the water intake core tube. The traction main cable passes through the central hole of the water intake core tube and is fixed to the inner wall of the water intake core tube. The outer wall of the water intake core tube is also provided with a hanging first support rod. Multiple first support rods are annularly hinged around the water intake core tube. The lower end of the first support rod is fixedly connected to the upper side of the expansion bladder. The end of the first support rod is conical and extends out of the expansion bladder. The first support rod is also connected to an auxiliary traction cable.

[0008] The water-conducting core tube is also provided with a through-hole drainage hole, which is connected to the inside of the expansion bladder.

[0009] The water-diverting core tube is also provided with a second support rod. The first support rod and the second support rod are parallel and arranged in a vertical group. A tension rod is also provided between the first support rod and the second support rod arranged in a vertical group. The first support rod, the second support rod, the tension rod and the water-diverting core tube form a parallelogram structure. The free end of the second support rod is fixedly connected to the side wall of the expansion bladder.

[0010] A fixing ring is provided on the upper side of the water intake core tube. The fixing ring is fixedly connected to the traction main cable. The fixing ring is fixedly connected to the inner wall of the water intake core tube by means of a set of spoke-shaped support plates. The lower end of the water intake core tube is funnel-shaped.

[0011] The water collector is located at the end of the traction main cable. The water collector includes a water intake pipe and a first solenoid valve and a second solenoid valve located at both ends of the water intake pipe. The lower end of the water intake pipe is connected to a connecting hose. A water pump located on the ground is connected to the water intake pipe via the connecting hose.

[0012] The traction main cable is connected to the middle section of the water intake pipe, the center of gravity of the water intake pipe is located above the connection point of the traction main cable, and an enlarged water storage cavity is provided on the water intake pipe below the connection point of the traction main cable.

[0013] The beneficial effects of this invention are: This invention adds a blocking device to guide the seepage water above the sampling layer away, making the water sampled from the sampling layer more accurate and avoiding cross-contamination. The method of using a water sampler to lean against the well wall avoids insertion into the well wall, reducing the sediment content in the sampled water and preventing blockage of the water sampler and pump. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram showing the well wall blocked by the blocking device; Figure 3 This is a schematic diagram of the water intake core pipe viewed from above. Figure 4 This is a schematic diagram showing the swinging of the water intake pipe. In the attached diagram, 1 is the main traction cable, 2 is the water intake core tube, 3 is the expansion bladder, 4 is the first support rod, 5 is the auxiliary traction cable, 6 is the drain hole, 7 is the second support rod, 8 is the traction rod, 9 is the fixing ring, 10 is the support plate, 11 is the water intake pipe, 12 is the first solenoid valve, 13 is the second solenoid valve, 14 is the connecting hose, and 15 is the water storage chamber. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Specific implementation examples Figure 1 As shown, the present invention is a groundwater sampling well anti-cross-layer sampling method, comprising the following methods: S1. Pour clean water into the sampling well and rinse the well wall, then pump out the mixed water from the bottom of the sampling well; S2. Install a blocking device inside the sampling well to intercept the seepage water above the sampling layer; S3. A water sampler is installed in the sampling well below the blocking device. The water sampler is located at the bottom of the sampling layer, and the pipe opening of the water sampler rests against the well wall to collect seepage water. S4. After sampling is completed, the inlet of the water sampler is sealed, the blocking device is removed, and the water sampler is retrieved to complete the sampling.

[0016] The well wall is rinsed with clean water to remove sand and other adhering materials from the surface of the well wall and to remove the cross-layer water that has flowed onto the sampling layer tube wall.

[0017] In step S2, after the blocking device is set up, wait 1.5-2 hours before opening the water sampler's port to collect samples.

[0018] By waiting for a period of time, allowing the groundwater layer to continue to seep water, a self-cleaning effect is achieved, so that the water permeating the sampling layer can better reflect the data of the sampling layer.

[0019] After the blocking device intercepts the water above the sampling layer, it guides it away through the inner diameter of the water inlet core pipe 2. The water in the upper layer is guided by the water inlet core pipe 2 and the traction main cable 1 to flow into the bottom of the well, and no longer flows with the well wall, thus avoiding cross-layering.

[0020] Furthermore, such as Figure 1 As shown, the blocking device includes a traction main cable 1, a water intake core tube 2, and an expansion bladder 3 arranged in a U-shape around the outside of the water intake core tube 2. The traction main cable 1 passes through the central hole of the water intake core tube 2 and is fixed to the inner wall of the water intake core tube 2. The outer wall of the water intake core tube 2 is also provided with a hanging first support rod 4. Multiple first support rods 4 are annularly hinged around the water intake core tube 2. The lower end of the first support rod 4 is fixedly connected to the upper side of the expansion bladder 3. The end of the first support rod 4 is conical and extends out of the expansion bladder 3. The first support rod 4 is also connected to an auxiliary traction cable 5.

[0021] As the main traction cable 1 is lowered into the sampling well, the first support rod 4 hangs down due to its own weight and the traction of the expansion bag 3, and will not hook onto the well wall. When the main traction cable 1 is lowered to a predetermined length, that is, when the blocking device is above the sampling layer, the auxiliary traction cable 5 is pulled, causing the first support rod 4 to open. With the help of the first support rod 4, which is inserted obliquely into the well wall, the part of the expansion bag 3 connected to the first support rod 4 is tightly attached to the well wall. As the seepage water gradually flows into the expansion bag 3, the expansion bag 3 gradually expands and sticks tightly to the well wall, thereby trapping the seepage water in the expansion bag 3.

[0022] like Figure 2 As shown, a through-hole 6 is also provided on the side wall of the water inlet core tube 2, and the drain hole 6 is connected to the inside of the expansion bladder 3.

[0023] When the water level in the expansion bladder 3 gradually rises to the height of the drain hole 6, the excess seepage water enters the water inlet core pipe 2 through the drain hole 6 and then falls to the bottom of the well through the water inlet core pipe 2.

[0024] Furthermore, the water-diverting core tube 2 is also provided with a second support rod 7. The first support rod 4 and the second support rod 7 are parallel and arranged in a vertical group. A tension rod 8 is also provided between the vertically grouped first support rod 4 and second support rod 7. The first support rod 4, the second support rod 7, the tension rod 8 and the water-diverting core tube 2 form a parallelogram structure. The free end of the second support rod 7 is fixedly connected to the side wall of the expansion bladder 3.

[0025] The expansion bag 3 is supported by the second support rod 7 and the first support rod 4, so that the expansion bag 3 can fit against the well wall for a longer length during the fitting process, resulting in better sealing and drainage effects.

[0026] Furthermore, a fixing ring 9 is provided on the upper side of the water intake core tube 2. The fixing ring 9 is fixedly connected to the traction main cable 1. The fixing ring 9 is fixedly connected to the inner wall of the water intake core tube 2 by means of a set of spoke-shaped support plates 10. The lower end of the water intake core tube 2 is configured as a funnel shape.

[0027] like Figure 3 As shown, the fixed ring 9 is supported by the spoke-shaped support plate 10, so that a space is formed between the fixed ring 9 and the water inlet core pipe 2 for other pipelines to pass through. The fixed ring 9 has a positioning screw inserted through its side wall. The positioning screw passes through the fixed ring 9 and is inserted into the traction main cable 1 for fixation. When the seepage water enters the water inlet core pipe 2, it flows down along the middle of the well barrel with the help of the funnel-shaped structure, avoiding flowing along the well wall. The traction main cable 1 passes through the center of the funnel shape, which plays a guiding role in the water flow and prevents the water from splashing onto the well wall and causing crossflow.

[0028] The bottom of the inflatable sac 3 is as follows Figure 2 As shown, due to the water pressure forming an arc, a small amount of water seeping from between the expansion bag 3 and the well wall falls along the expansion bag 3 and down the well cavity, reducing the flow rate on the well wall and preventing cross-layering.

[0029] Furthermore, such as Figure 4 As shown, the water collector is located at the end of the traction main cable 1. The water collector includes a water intake pipe 11 and a first solenoid valve 12 and a second solenoid valve 13 located at both ends of the water intake pipe 11. The lower end of the water intake pipe 11 is connected to a connecting hose 14, and a water pump located on the ground is connected to the water intake pipe 11 via the connecting hose 14. The traction main cable 1 is connected to the middle section of the water intake pipe 11, and the center of gravity of the water intake pipe 11 is located above the connection point of the traction main cable 1. An enlarged water storage chamber 15 is provided on the water intake pipe 11 below the connection point of the traction main cable 1.

[0030] The water sampler is located at the bottom of the sampling layer. Therefore, the length of the traction cable 1 between the water sampler and the blocking device is equal to the thickness of the sampling layer. Since the center of the water sampler's intake pipe 11 is high, the upper end of the intake pipe 11 is always close to the well wall. After the water sampler descends to its position with the traction cable 1, the first solenoid valve 12 and the second solenoid valve 13 are opened, allowing the seepage water to enter the intake pipe 11 and be drawn to the ground by the connecting hose 14. After sufficient sampling water is drawn, the first solenoid valve 12 is closed, while the second solenoid valve 13 remains open. At this time, as the water storage chamber 15 continuously stores water, the center of gravity of the intake pipe 11 moves downward. Figure 4 As shown, the upper end of the water intake pipe 11 detaches from the well wall and is in an upright state. At this time, the traction main cable 1 is directly retracted, the first support rod 4 is pulled out from the well wall, and the expansion bag 3 loses its tension. Under the action of gravity, the expansion bag 3 is squeezed out by the downward swing of the first support rod 4 and the second support rod 7, which facilitates the removal of the blocking device and the water intake device. The whole process is simple to operate and the equipment structure is simple, effectively avoiding the problem of cross-layering caused by water seepage from the well wall during groundwater sampling.

Claims

1. A groundwater sampling well anti-cross-layer sampling method, characterized in that: Including the following methods, S1. Pour clean water into the sampling well and rinse the well wall, then pump out the mixed water from the bottom of the sampling well; S2. Install a blocking device inside the sampling well to intercept the seepage water above the sampling layer; S3. A water sampler is installed in the sampling well below the blocking device. The water sampler is located at the bottom of the sampling layer, and the pipe opening of the water sampler rests against the well wall to collect seepage water. S4. After sampling is completed, the inlet of the water sampler is sealed, the blocking device is removed, and the water sampler is retrieved to complete the sampling. The blocking device includes a traction main cable (1), a water intake core tube (2), and an expansion bladder (3) arranged in a U-shape around the outside of the water intake core tube (2). The traction main cable (1) passes through the central hole of the water intake core tube (2) and is fixed to the inner wall of the water intake core tube (2). The outer wall of the water intake core tube (2) is also provided with a hanging first support rod (4). Multiple first support rods (4) are annularly hinged around the water intake core tube (2). The lower end of the first support rod (4) is fixedly connected to the upper side of the expansion bladder (3). The end of the first support rod (4) is conical and extends out of the expansion bladder (3). The first support rod (4) is also connected to an auxiliary traction cable (5). The water inlet core tube (2) is also provided with a through drain hole (6) on its side wall, and the drain hole (6) is connected to the inside of the expansion bladder (3); When the water level in the expansion bladder (3) gradually rises to the height of the drain hole (6), the excess seepage water enters the water inlet core pipe (2) from the drain hole (6) and then falls to the bottom of the well from the water inlet core pipe (2), no longer flowing with the well wall, thus avoiding cross-layering.

2. The groundwater sampling well anti-cross-layer sampling method according to claim 1, characterized in that: In step S2, after the blocking device is set up, wait 1.5-2 hours before opening the water sampler's port to collect samples.

3. The groundwater sampling well anti-cross-layer sampling method according to claim 1, characterized in that: The water-diverting core tube (2) is also provided with a second support rod (7). The first support rod (4) and the second support rod (7) are parallel and arranged in a vertical group. A traction rod (8) is also provided between the first support rod (4) and the second support rod (7) arranged in a vertical group. The first support rod (4), the second support rod (7), the traction rod (8) and the water-diverting core tube (2) form a parallelogram structure. The free end of the second support rod (7) is fixedly connected to the side wall of the expansion bladder (3).

4. The groundwater sampling well anti-cross-layer sampling method according to claim 1, characterized in that: A fixing ring (9) is provided on the upper side of the water intake core tube (2). The fixing ring (9) is fixedly connected to the traction main cable (1). The fixing ring (9) is fixedly connected to the inner wall of the water intake core tube (2) by means of a set of spoke-shaped support plates (10). The lower end of the water intake core tube (2) is set in the shape of a funnel.

5. The groundwater sampling well anti-cross-layer sampling method according to claim 1, characterized in that: The water collector is located at the end of the traction main cable (1). The water collector includes a water pipe (11) and a first solenoid valve (12) and a second solenoid valve (13) located at both ends of the water pipe (11). A connecting hose (14) is connected to the lower end of the water pipe (11). A water pump located on the ground is connected to the water pipe (11) via the connecting hose (14).

6. The groundwater sampling well anti-cross-layer sampling method according to claim 5, characterized in that: The traction main cable (1) is connected to the middle section of the water intake pipe (11). The center of gravity of the water intake pipe (11) is located above the connection point of the traction main cable (1). An enlarged water storage cavity (15) is provided on the water intake pipe (11) below the connection point of the traction main cable (1).

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