Soil gas sampler, sampling method, detection method and dynamic change monitoring method

Abstract

The invention discloses a soil gas sampler, a sampling method, a detection method and a dynamic change monitoring method, which belong to the technical field of soil gas detection. The invention comprises a sleeve, wherein a sampler is installed inside the sleeve. The sampling method of the soil gas sampler comprises: a first step, implanting the soil gas sampler; a second step, exhausting and gas replacement; a third step, soil gas sampling, and also comprises a soil gas detection method and a soil gas dynamic change monitoring method. The working process of the monitoring method is as follows: a first step, dynamic index detection; a second step, soil gas detection; a third step, fitting calculation; a fourth step, difference curve calculation; a fifth step, soil gas dynamic change monitoring output; a sixth step, soil gas content expression. The soil gas sampler, sampling method, detection method and dynamic change monitoring method of the invention have accurate soil gas sampling and detection, and can accurately characterize the actual soil gas content of the sampling point.

Description

Technical Field

[0001] The present invention specifically relates to a soil gas sampler, a sampling method, a detection method and a dynamic change monitoring method, and belongs to the technical field of soil gas detection. Background Art

[0002] Accurately collecting soil gas samples is a prerequisite for studying the content of CO2, O2 and volatile organic pollutants in soil gas. In the prior art, the methods of collecting soil gas mainly include directly drilling holes to sample gas, or sampling and sealing the soil. The error of measuring soil gas by soil is large. Therefore, most of them use direct collection of soil gas for measurement; For example, Chinese Patent Publication No.: 112523678A discloses a soil gas monitoring hole forming device and its forming method and soil gas monitoring hole structure, the device includes: a drill bit, a wall protection sleeve, the wall protection sleeve The sleeve has a relative lower open end and an upper open end for mounting on the driving device, the lower open end is detachably connected to the drill bit; and an air pipe for connecting the vacuum pump is passed through the wall protection sleeve. This structure adopts single-point vacuum sampling and can accurately enter the detection point, but this structure cannot perform multi-point detection. In addition, when the existing sampling head enters the soil, it is easy to cause a large collection error due to the gas brought in during the drilling process. If the vacuum treatment is directly adopted, it is easy to cause the vacuum backflow at the moment of vacuum shutdown, and it is impossible to fully remove the gas brought in. The gas is completely discharged. Therefore, before sampling, it is necessary to continue to evacuate the sampling point for a long time until the surrounding soil gas is exhausted and then turn off the vacuum pump. This method is easy to damage the environment of the sampling point. In addition, when the sampling pipeline intermittently samples multiple sampling points, the sampling tube is easily disturbed by the temporarily stored soil gas, resulting in errors between the soil gas sampling at each point and the actual results. In addition, since there are many soil gas detection objects, the existing sampling points and detection points are separated. Therefore, when the soil gas sample is transferred from the sampling point to the detection point, or when the detection point is detected, errors cannot be discovered in time. Moreover, most of the existing sampling equipment is one-time sampling, and soil gas sampling is instantaneous. Since soil gas is a dynamic process, it will be affected by environmental factors such as air pressure and weather temperature and humidity. Therefore, the current single collection cannot accurately characterize the actual situation of soil gas content. Some collection schemes will collect multiple times and characterize them by taking the average. This method cannot ensure that the collected data is characteristic. For example, the two previous and subsequent collections are both on the high line or both on the low line, thereby raising or lowering the entire mean, making the detection data lack accuracy. Summary of the invention

[0003] To solve the above problems, the present invention proposes a soil gas sampler, a sampling method, a detection method and a dynamic change monitoring method. The soil gas sampling and detection are accurate and can accurately characterize the actual soil gas content at the sampling point.

[0004] The soil gas sampler of the present invention comprises a sleeve, a sampler is installed inside the sleeve, the sleeve comprises a columnar barrel, the barrel is provided with multiple ring-shaped grids at intervals, the bottom of the barrel is a conical structure, the sampler comprises a tube body composed of a thick-diameter tube and a thin-diameter tube staggered and screwed together, the thin-diameter tube is provided with mesh holes, and the inside is filled with a non-adsorbent filler, that is, an adsorbent material such as carbon material cannot be used, and the filler is used to filter the gas containing soil; the outer wall of the thick-diameter tube is provided with a sealing ring, the sealing ring is tightly pressed with the inner wall of the sleeve, and the inside of the thick-diameter tube is sealed into multiple spaces by the sealing ring , each space corresponds to a sampling point; the thin-diameter tube is directly opposite to the strip grid; a plurality of rolling balls that fit each other are arranged in the strip grid; the rolling balls can be guided circumferentially or axially when the sleeve is drilled or screwed into the soil, and at the same time, the rolling balls are rotated by friction between them to avoid soil blocking the rolling balls, so as to maintain smooth detection and air extraction; the inner bottom of the thick-diameter tube is integrally made of a mesh plate, and the aperture of the mesh plate is smaller than the particle size of the filler; a cover body is arranged on the top of the mesh plate, and a main pipe and an electric-controlled sampling valve are arranged on the top of the cover body; the main pipe is connected to the electric-controlled sampling valve; the main pipe passes through filler, and connected with the main pipe inside the adjacent large-diameter pipe; the diaphragm pump provides power to allow soil gas to enter the small-diameter pipe from the sampling point through the strip grid, rolling ball, and mesh of the small-diameter pipe, and enter the main pipe through the cover body and the electric-controlled sampling valve. Since the electric-controlled sampling valve can disconnect each sampling point, mutual interference of sampling can be avoided; the bottom surface of the main pipe arranged at the bottom is sealed to avoid air extraction from the bottom surface of the main pipe at the bottom when the diaphragm pump is working; a sealing plate is fixed to the top of the cylinder through a flange. When the sealing plate is installed, it is pressed into the ground or buried inside the ground. An outer pipe is arranged on the sealing plate, and the outer pipe is connected to the main pipe arranged at the top. The outer tube is connected with an inner tube body, and the inner tube body extends to the inner bottom of the outer tube. The inner tube body is connected to the clean gas pressure tank. The outer tube is also connected to the one-way valve of at least one gas storage tank through a diaphragm pump. A pressure gauge is installed at the input end of the diaphragm pump. The outer tube is provided with a drain valve on the output side of the diaphragm pump, and the drain valve is used for purifying the pipeline, and the purified gas is discharged from the drain valve. The gas storage tank is provided with a detection exhaust valve. When the gas storage tank completes gas storage and needs to be tested, the detection pipeline is connected to the detection exhaust valve, and the detection exhaust valve is opened to perform the detection.

[0005] Furthermore, the power line and control line of the electric-controlled sampling valve pass through the filler, mesh plate and cover body and extend to the outside of the sealing plate; the cover body and sealing plate are injected with resin or rubber sealing material at the position where the power line and control line pass through; when the power line and control line are led out from the inside of the sampler, the lead-out hole is filled and sealed with resin or rubber.

[0006] The soil gas sampling method uses a soil gas sampler to take samples. The sampling process is as follows:

[0007] The first step is to implant the soil gas sampler, knock or screw the assembled sleeve and sampler into the detection point according to the depth requirements; and complete the connection of the lines and pipelines;

[0008] The second step is exhaust and gas replacement. When exhausting, open all the electronically controlled sampling valves and the drain valve, then open the diaphragm pump, and use the diaphragm pump to evacuate the area around the sampling point so that the pressure value around the sampling point reaches the set vacuum value. Then, close the drain valve and the diaphragm pump, and open the valve of the clean gas pressure tank to inject clean gas into the inner tube body. The clean gas is a gas that does not affect the indicators of the test object, such as nitrogen gas. After the injected gas reaches the set pressure, close the valve of the clean gas pressure tank. After completing the temporary replacement of the gas at the sampling point, evacuate the sampling point according to the exhaust steps to reach the set vacuum value. Close the electronically controlled sampling valve. Complete the exhaust and gas replacement of all sampling points. Through the replacement method, it is only necessary to evacuate before and after the replacement. The replacement gas is first filled and squeezed to squeeze the unexhausted gas. Then, the gas is discharged by vacuuming. The clean gas that is not fully discharged does not affect the subsequent test results.

[0009] The third step is soil gas sampling. The sampling order is from deep to shallow. When sampling, open the deepest electric sampling valve, then open the diaphragm pump, and use the diaphragm pump to extract the soil gas at this point into the clean gas pressure tank, and monitor it in real time through the pressure gauge. When the pressure value at the sampling point drops to the set low level, the electric sampling valve is closed and the diaphragm pump is shut down; the one-way valve of the gas storage tank automatically closes the sampled gas, waits for the soil gas detection inside the gas storage tank, completes the soil gas sampling at the sampling point at this position, and then proceeds to the previous deep sampling point. Before sampling the soil gas at the previous depth, close all the electronically controlled sampling valves, open the drain valve, and open the valve of the clean gas pressure tank, inject clean gas into the inner tube body, output clean gas from the bottom of the inner tube body, and blow the main tube and the outer tube; after the blowing is completed, open the diaphragm pump and the exhaust valve for secondary exhaust, and finally perform soil gas sampling at the previous depth, and sample the soil gas at each depth sampling point in turn; the sampling polling time adopts timed polling, and when the polling time is reached, a new round of soil gas collection is triggered.

[0010] A soil gas detection method comprises a soil gas sampler, wherein the detection exhaust valve is an electrically controlled opening valve, the detection exhaust valve is provided with a flow meter at the output end, and the electrically controlled opening valve is connected to a gas detector; the soil gas sampled each time is detected and recorded by the gas detector; and the data is locally stored or uploaded to a remote processing terminal; the flow in a gas storage tank is measured by the flow meter, and the gas detector measures each component at the same time, so as to obtain the total amount of gas in the gas storage tank and the content of each component in the gas.

[0011] The method for monitoring the dynamic change of soil gas includes a soil gas sampler and a gas detector, and also includes a single-indicator online detector installed inside a cover body, wherein the single-indicator online detector and the gas detector are connected to a dynamic monitoring controller, and the dynamic monitoring controller is also connected to a meteorological monitor, and the meteorological monitor is installed in a soil detection area; the working process of the monitoring method is as follows:

[0012] The first step is dynamic index detection. The dynamic monitoring controller performs sampling at a fixed time in the sampling cycle. When the sampling time is reached, the dynamic monitoring controller sends a signal to the single index online detector. Then, the dynamic monitoring controller sends a signal to the soil gas sampler and the meteorological monitor. The soil gas sampler collects soil gas at each fixed depth sampling point. The meteorological monitor obtains the current air pressure and air temperature and humidity data. The single index online detector and the meteorological monitor send the detection data to the dynamic monitoring controller.

[0013] The second step is soil gas detection. The soil gas collected in the first step is sent to the gas detector, which quantitatively detects the soil gas composition and sends the detection data to the dynamic monitoring controller in a timeline;

[0014] The third step is fitting calculation; the fitting calculation process is as follows: a three-dimensional coordinate system is established based on the measured data, with temperature data as the X-axis, humidity or air pressure as the Y-axis, and the total amount of a certain detection index in the soil gas as the Z-axis, and the data A corresponding to each time point obtained by the dynamic monitoring controller is n (x n ,y n 、z n ) falls into a three-dimensional coordinate system, A indicates a certain punctuation point in the three-dimensional coordinate system, n indicates a certain time point, x is temperature data, y is humidity or air pressure data, and z is a certain index data measured in soil gas; obtain three-dimensional data, construct a surface with the three-dimensional data through Matab and obtain a fitting formula or find a fitting formula through TableCurve3D, and according to the fitting calculation process, establish fitting formulas under meteorological conditions for all the indicators measured in soil gas one by one;

[0015] The fourth step is to calculate the difference curve. The dynamic monitoring controller performs a difference operation on the data collected by the single-indicator online detector and the same indicator data detected by the gas detector, and obtains the difference into a difference fitting formula according to the fitting calculation method in the third step.

[0016] The fifth step is to monitor and output the dynamic changes of soil gas. The dynamic monitoring controller sends the data collected by the meteorological monitor in real time into the fitting formula under various meteorological conditions, outputs all the index data in the soil gas, and then sends the data collected by the single-index online detector in real time into the difference fitting formula to calculate the corresponding index data in the soil gas. The dynamic monitoring controller compares the output result of the difference fitting formula with the output result of the fitting formula under meteorological conditions for the detection object of the single-index online detector. If the error is within the set range, the output of all the index data in the soil gas by the meteorological monitor is used as the result output; when the error between the two exceeds the set range, the inspection and correction process is entered; the inspection and correction process is to add an additional sampling and detection process; and the fitting curve and / or the difference fitting curve under meteorological conditions are corrected with the actual results.

[0017] The sixth step is to express the soil gas content. The soil gas content is measured by calculating the mean of the dynamically changing data. The temperature value, temperature value or air pressure value of the whole year of the monitoring year or the previous year is used as the input object, and a data group with the same number or a multiple of the number of days in the year is output. The data group is averaged and the calculated value is used as the soil gas content representation value.

[0018] Compared with the prior art, the soil gas sampler, sampling method, detection method and dynamic change monitoring method of the present invention have the following advantages:

[0019] The drill bit is screwed or pressed into the detection point, which causes little damage to the surrounding soil layer. During the detection, multiple depth sampling can be carried out on the same axis. The gas enters the sampling position after being filtered, and the sampling safety is good.

[0020] Through the replacement method, it is only necessary to evacuate the air before and after the replacement, and use the replacement gas flow to fill and squeeze the unexhausted gas. Then, the gas is exhausted by vacuuming. The clean gas that is not fully exhausted will not affect the subsequent test results. The test pipeline can be jet-purified before and after the test to ensure the accuracy of sampling.

[0021] A single indicator detection sensor is set at the sampling point. By comparing a certain indicator data detected by the single indicator detection sensor with the corresponding indicator data output by the detector, it can be determined whether there is an error in the collection and detection process.

[0022] It can characterize the soil gas dynamic curve, and quantitatively evaluate and characterize the soil gas content by taking the average of the dynamic curve, making the detection more consistent with the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the installation structure of the sleeve and the sampler of the present invention.

[0024] Figure 2It is a schematic diagram of the internal structure of the sleeve of the present invention.

[0025] Figure 3 It is a schematic diagram of the installation structure of the inner tube body and the outer tube of the present invention.

[0026] Figure 4 It is a schematic diagram of the overall structure of the soil gas sampler of the present invention.

[0027] Figure numerals: cylinder 1, strip grid 2, rolling ball 21, thick diameter tube 3, thin diameter tube 4, mesh 5, filler 6, sealing ring 7, cover 8, main pipe 9, electric control sampling valve 10, sealing plate 11, outer tube 12, inner tube body 13, clean gas pressure tank 14, diaphragm pump 15, gas storage tank 16, one-way valve 17, pressure gauge 18, drain valve 19, detection exhaust valve 20, single indicator online detector 21. DETAILED DESCRIPTION

[0028] Embodiment 1:

[0029] like Figures 1 to 4The soil gas sampler shown comprises a sleeve, a sampler is installed inside the sleeve, the sleeve comprises a columnar barrel 1, the barrel 1 is provided with a plurality of ring-shaped strip grids 2 at intervals, the bottom of the barrel 1 is a conical structure, the sampler comprises a tube body composed of a thick-diameter tube 3 and a thin-diameter tube 4 staggered and screwed together, the thin-diameter tube 4 is provided with a mesh 5, and the inside is filled with a non-adsorbent filler 6, that is, carbon material adsorbent material cannot be used, and the filler 6 is used to filter the gas containing soil; the outer wall of the thick-diameter tube 3 is provided with a sealing ring 7, the sealing ring 7 is tightly pressed against the inner wall of the sleeve, and the inside of the thick-diameter tube 4 is sealed into a plurality of spaces by the sealing ring 7, each space corresponding to a sampling point ; The thin-diameter tube 4 is directly opposite to the strip grid 2; a plurality of rolling balls 21 that fit each other are arranged in the strip grid 2; the rolling balls 21 can be guided circumferentially or axially when the sleeve is drilled or screwed into the soil, and the rolling balls 21 can be rotated by friction between the rolling balls 21 to avoid soil blocking the rolling balls 21, so as to maintain smooth detection and extraction; the bottom of the inner side of the thick-diameter tube 3 is integrally made of a mesh plate, and the aperture of the mesh plate is smaller than the particle size of the filler; a cover body 8 is arranged on the top of the mesh plate, and a main pipe 9 and an electrically controlled sampling valve 10 are arranged on the top of the cover body 8; the main pipe 9 is connected to the electrically controlled sampling valve 10; the main pipe 9 passes through the filler 6 and is connected to the main pipe on the inner side of the adjacent thick-diameter tube 3 9 is connected; the diaphragm pump provides power to allow soil gas to enter the narrow-diameter tube 4 from the sampling point through the strip grid 2, the rolling ball 21, and the mesh of the narrow-diameter tube 4, and enter the main tube 9 through the cover body 8 and the electric-controlled sampling valve 10. Since the electric-controlled sampling valve 10 can disconnect each sampling point, mutual interference between samplings can be avoided; the bottom surface of the main tube 9 arranged at the bottom is sealed to avoid air being drawn from the bottom surface of the main tube 9 at the bottom when the diaphragm pump is working; a sealing plate 11 is fixed to the top of the cylinder 1 through a flange. When the sealing plate 11 is installed, it is pressed into the ground or buried inside the ground. An outer tube 12 is arranged on the sealing plate 11, and the outer tube 12 is connected to the top of the main tube 9 arranged at the top; the outer tube 12 is connected to The inner tube body 13 extends to the inner bottom of the outer tube 12, the inner tube body 13 is connected to the clean gas pressure tank 14, and the outer tube 12 is also connected to the one-way valve 17 of at least one gas storage tank 16 through a diaphragm pump 15; the input end of the diaphragm pump 16 is installed with a pressure gauge 18; the outer tube 12 is provided with an exhaust valve 19 on the output side of the diaphragm pump 16, and the exhaust valve 19 is used for purifying the pipeline, and the purified gas is discharged from the exhaust valve; the gas storage tank 16 is provided with a detection exhaust valve 20. After the gas storage tank 16 completes gas storage, when detection is required, the detection can be carried out by connecting the detection pipeline to the detection exhaust valve 20 and opening the detection exhaust valve 20.

[0030] The power line and control line of the electric-controlled sampling valve 10 pass through the filler 6, the mesh plate and the cover body 8 and extend to the outside of the sealing plate 11; the cover body 8 and the sealing plate 11 are filled with resin or rubber sealing materials at the positions where the power line and the control line pass through; when the power line and the control line are led out from the inside of the sampler, the lead-out hole is filled and sealed with resin or rubber.

[0031] A soil gas sampling method is provided, wherein sampling is performed by a soil gas sampler, and the sampling process is specifically as follows:

[0032] The first step is to implant the soil gas sampler, knock or screw the assembled sleeve and sampler into the detection point according to the depth requirements; and complete the connection of the lines and pipelines;

[0033] The second step is exhaust and gas replacement. When exhausting, open all the electronically controlled sampling valves 10 and the drain valve 19, then open the diaphragm pump 15, and use the diaphragm pump 15 to evacuate the area around the sampling point so that the pressure value around the sampling point reaches the set vacuum value. Then, close the drain valve 19 and the diaphragm pump 15, and open the valve of the clean gas pressure tank 14 to inject clean gas into the inner tube 13. The clean gas is a gas that does not affect the indicators of the detection object, such as nitrogen gas. After the injected gas reaches the set pressure, close the valve of the clean gas pressure tank 14. Complete the temporary replacement of the gas at the sampling point, and then evacuate the sampling point according to the exhaust steps to reach the set vacuum value. Close the electronically controlled sampling valve 10. Complete the exhaust and gas replacement of all sampling points. Through the replacement method, it is only necessary to evacuate before and after the replacement. The replacement gas is first filled and squeezed to squeeze the unexhausted gas, and then the gas is discharged by vacuuming. The clean gas that is not fully discharged does not affect the subsequent detection results.

[0034] The third step is soil gas sampling. The sampling order is from deep to shallow. When sampling, open the deepest electric sampling valve 10, then open the diaphragm pump 15, and extract the soil gas at this point to the clean gas pressure tank 14 through the diaphragm pump 15, and monitor it in real time through the pressure gauge 18. When the pressure value at the sampling point drops to the set low level line, the electric sampling valve 10 is closed and the diaphragm pump 15 is shut down; the one-way valve 17 of the gas storage tank 16 automatically closes the sampled gas, waits for the soil gas detection inside the gas storage tank 16, completes the soil gas sampling at the sampling point at this position, and then proceeds Soil gas sampling at the previous depth; before soil gas sampling at the previous depth, close all the electrically controlled sampling valves 10, open the drain valve 19, and open the valve of the clean gas pressure tank 14, inject clean gas into the inner tube body, output clean gas from the bottom of the inner tube body 13, and blow the main tube 9 and the outer tube 12; after the blowing is completed, open the diaphragm pump 15 and the exhaust valve 20 for secondary exhaust, and finally perform soil gas sampling at the previous depth, and sample the soil gas at each depth sampling point in turn; the sampling polling time adopts timed polling, and when the polling time is reached, a new round of soil gas collection is triggered.

[0035] A soil gas detection method includes a soil gas sampler, wherein the detection exhaust valve 20 is an electrically controlled opening valve, the detection exhaust valve 20 is provided with a flow meter at the output end, and the electrically controlled opening valve 20 is connected to a gas detector; the soil gas sampled each time is detected and recorded by the gas detector; and the data is locally stored or uploaded to a remote processing terminal; the flow in a gas storage tank 16 is measured by the flow meter, and the gas detector measures each component, thereby obtaining the total amount of gas in the gas storage tank 16 and the content of each component in the gas.

[0036] A soil gas dynamic change monitoring method includes a soil gas sampler and a gas detector, and also includes a single indicator online detector 21 installed on the inner side of a cover 8, the single indicator online detector 21 and the gas detector are connected to a dynamic monitoring controller, the dynamic monitoring controller is also connected to a meteorological monitor, and the meteorological monitor is installed in a soil detection area; the working process of the monitoring method is as follows:

[0037] The first step is dynamic index detection. The dynamic monitoring controller performs sampling at a fixed time in the sampling cycle. When the sampling time is reached, the dynamic monitoring controller sends a signal to the single index online detector. Then, the dynamic monitoring controller sends a signal to the soil gas sampler and the meteorological monitor. The soil gas sampler collects soil gas at each fixed depth sampling point. The meteorological monitor obtains the current air pressure and air temperature and humidity data. The single index online detector and the meteorological monitor send the detection data to the dynamic monitoring controller.

[0038] The second step is soil gas detection. The soil gas collected in the first step is sent to the gas detector, which quantitatively detects the soil gas composition and sends the detection data to the dynamic monitoring controller in a timeline;

[0039] The third step is fitting calculation; the fitting calculation process is as follows: a three-dimensional coordinate system is established based on the measured data, with temperature data as the X-axis, humidity or air pressure as the Y-axis, and the total amount of a certain detection index in the soil gas as the Z-axis, and the data A corresponding to each time point obtained by the dynamic monitoring controller is n (x n ,y n 、z n) falls into a three-dimensional coordinate system, A indicates a certain punctuation point in the three-dimensional coordinate system, n indicates a certain time point, x is temperature data, y is humidity or air pressure data, and z is a certain index data measured in soil gas; obtain three-dimensional data, construct a surface with the three-dimensional data through Matab and obtain a fitting formula or find a fitting formula through TableCurve3D, and according to the fitting calculation process, establish fitting formulas under meteorological conditions for all the indicators measured in the soil gas one by one; the dynamic monitoring controller fits all the data collected recently, such as obtaining the volatile organic pollutant index data measured in the soil gas corresponding to different temperatures and humidities according to the detected data, and performs a fitting calculation formula: D=3.41621lnt+0.721c+11.7314; wherein D is the volatile organic pollutant index data, t is the temperature data, and c is the humidity data; finally, establish a three-dimensional model based on the measured three-dimensional data;

[0040] The fourth step is to calculate the difference curve. The dynamic monitoring controller performs a difference operation on the data collected by the single-indicator online detector and the same indicator data detected by the gas detector, and obtains the difference into a difference fitting formula according to the fitting calculation method in the third step.

[0041] The fifth step is to monitor and output the dynamic changes of soil gas. The dynamic monitoring controller sends the data collected by the meteorological monitor in real time into the fitting formula under various meteorological conditions, outputs all the index data in the soil gas, and then sends the data collected by the single-index online detector in real time into the difference fitting formula to calculate the corresponding index data in the soil gas. The dynamic monitoring controller compares the output result of the difference fitting formula with the output result of the fitting formula under meteorological conditions for the detection object of the single-index online detector. If the error is within the set range, the output of all the index data in the soil gas by the meteorological monitor is used as the result output; when the error between the two exceeds the set range, the inspection and correction process is entered; the inspection and correction process is to add an additional sampling and detection process; and the fitting curve and / or the difference fitting curve under meteorological conditions are corrected with the actual results.

[0042] The sixth step is to express the soil gas content. The soil gas content is measured by calculating the mean of the dynamically changing data. The temperature value, temperature value or air pressure value of the whole year of the monitoring year or the previous year is used as the input object, and a data group with the same number or a multiple of the number of days in the year is output. The data group is averaged and the calculated value is used as the soil gas content representation value.

[0043] The above embodiments are only preferred implementations of the present invention, so all equivalent changes or modifications made according to the structures, features and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A soil gas sampling method, characterized in that: A soil gas sampler is used for sampling, the soil gas sampler comprises a sleeve, a sampler is installed inside the sleeve, the sleeve comprises a columnar cylinder, the cylinder is provided with multiple rings of strip grids at intervals, the bottom of the cylinder is a conical structure, the sampler comprises a tube body composed of a thick-diameter tube and a thin-diameter tube staggered and screwed together, the thin-diameter tube is provided with mesh holes, and the inside is filled with non-absorbent filler; a sealing ring is provided on the outer wall of the thick-diameter tube; the sealing ring is tightly pressed against the inner wall of the sleeve; the thin-diameter tube is directly opposite to the strip grid; a plurality of rolling balls that fit each other are provided in the strip grid; a mesh plate is integrally made at the bottom of the inner side of the thick-diameter tube; a cover is provided on the top of the mesh plate, and the A main pipe and an electric-controlled sampling valve are provided on the top of the cover body; the main pipe is connected to the electric-controlled sampling valve; the main pipe passes through the packing and is connected to the main pipe on the inner side of the adjacent large-diameter pipe; the bottom surface of the main pipe arranged at the bottom is sealed; a sealing plate is fixed to the top of the cylinder body through a flange, an outer pipe is provided on the sealing plate, and the outer pipe is connected to the top of the main pipe arranged on the top; the outer pipe is connected to an inner pipe body, the inner pipe body extends to the bottom of the inner side of the outer pipe, the inner pipe body is connected to the clean gas pressure tank, and the outer pipe is also connected to the one-way valve of at least one gas storage tank through a diaphragm pump; a pressure gauge is installed at the input end of the diaphragm pump; the outer pipe is provided with an emptying valve on the output side of the diaphragm pump; a detection exhaust valve is provided on the gas storage tank; The specific working process of the method is as follows: The first step is to implant the soil gas sampler, knock or screw the assembled sleeve and sampler into the detection point according to the depth requirements; and complete the connection of the lines and pipelines; The second step is exhaust and gas replacement. When exhausting, open all the electronically controlled sampling valves and the drain valve, then open the diaphragm pump, and use the diaphragm pump to evacuate the area around the sampling point so that the pressure value around the sampling point reaches the set vacuum value. Then, close the drain valve and the diaphragm pump, and open the valve of the clean gas pressure tank to inject clean gas into the inner tube. The clean gas is a gas that does not affect the indicators of the test object. After the injected gas reaches the set pressure, close the valve of the clean gas pressure tank. Complete the temporary replacement of the gas at the sampling point, and then evacuate the sampling point according to the exhaust steps to reach the set vacuum value. Close the electronically controlled sampling valve. Complete the exhaust and gas replacement of all sampling points. The third step is soil gas sampling. The sampling order is from deep to shallow. When sampling, open the deepest electric sampling valve, then open the diaphragm pump, and use the diaphragm pump to extract the soil gas at this point into the clean gas pressure tank, and monitor it in real time through the pressure gauge. When the pressure value at the sampling point drops to the set low level, the electric sampling valve is closed and the diaphragm pump is shut down; the one-way valve of the gas storage tank automatically closes the sampled gas, waits for the soil gas detection inside the gas storage tank, completes the soil gas sampling at the sampling point at this position, and then proceeds to the previous deep sampling point. Before sampling the soil gas at the previous depth, close all the electronically controlled sampling valves, open the drain valve, and open the valve of the clean gas pressure tank, inject clean gas into the inner tube body, output clean gas from the bottom of the inner tube body, and blow the main tube and the outer tube; after the blowing is completed, open the diaphragm pump and the exhaust valve for secondary exhaust, and finally perform soil gas sampling at the previous depth, and sample the soil gas at each depth sampling point in turn; the sampling polling time adopts timed polling, and when the polling time is reached, a new round of soil gas collection is triggered.

2. The soil gas sampling method according to claim 1, characterized in that: The power line and control line of the electric-controlled sampling valve pass through the filler, mesh plate and cover body and extend to the outside of the sealing plate; the cover body and the sealing plate are filled with resin or rubber sealing material at the position where the power line and control line pass through.

3. A soil gas detection method, wherein the soil gas sampling method according to claim 1 is used for sampling, characterized in that: The detection exhaust valve is an electrically controlled opening valve, a flow meter is provided at the output end of the detection exhaust valve, and the electrically controlled opening valve is connected to a gas detector; the soil gas sampled by the soil gas sampler each time is detected and recorded by the gas detector; and the data is locally stored or uploaded to a remote processing terminal; the flow in the gas storage tank is measured by the flow meter, and the gas detector measures each component at the same time, thereby obtaining the total amount of gas in the gas storage tank and the content of each component in the gas.

4. A method for monitoring soil gas dynamic changes, using the soil gas detection method of claim 3 for detection, characterized in that: It also includes a single-indicator online detector installed inside the cover body, the single-indicator online detector and the gas detector are connected to a dynamic monitoring controller, the dynamic monitoring controller is also connected to a meteorological monitor, and the meteorological monitor is installed in the soil detection area; the working process of the monitoring method is as follows: The first step is dynamic index detection. The dynamic monitoring controller performs sampling at a fixed time in the sampling cycle. When the sampling time is reached, the dynamic monitoring controller sends a signal to the single index online detector. Then, the dynamic monitoring controller sends a signal to the soil gas sampler and the meteorological monitor. The soil gas sampler collects soil gas at each fixed depth sampling point. The meteorological monitor obtains the current air pressure and air temperature and humidity data. The single index online detector and the meteorological monitor send the detection data to the dynamic monitoring controller. The second step is soil gas detection. The soil gas collected in the first step is sent to the gas detector, which quantitatively detects the soil gas composition and sends the detection data to the dynamic monitoring controller in a timeline; The third step is fitting calculation; the fitting calculation process is as follows: a three-dimensional coordinate system is established based on the measured data, with temperature data as the X-axis, humidity or air pressure as the Y-axis, and the total amount of a certain detection index in the soil gas as the Z-axis, and the data A corresponding to each time point obtained by the dynamic monitoring controller is n (x n ,y n 、z n ) falls into a three-dimensional coordinate system, A indicates a certain punctuation point in the three-dimensional coordinate system, n indicates a certain time point, x is temperature data, y is humidity or air pressure data, and z is a certain index data measured in soil gas; obtain three-dimensional data, construct a surface with the three-dimensional data through Matab and obtain a fitting formula or find a fitting formula through TableCurve3D, and according to the fitting calculation process, establish fitting formulas under meteorological conditions for all the indicators measured in soil gas one by one; The fourth step is to calculate the difference curve. The dynamic monitoring controller performs a difference operation on the data collected by the single-indicator online detector and the same indicator data detected by the gas detector, and obtains the difference into a difference fitting formula according to the fitting calculation method in the third step. The fifth step is to monitor and output the dynamic changes of soil gas. The dynamic monitoring controller sends the data collected by the meteorological monitor in real time into the fitting formula under various meteorological conditions, outputs all the index data in the soil gas, and then sends the data collected by the single index online detector in real time into the difference fitting formula to calculate the corresponding index data in the soil gas. The dynamic monitoring controller compares the output result of the difference fitting formula with the output result of the fitting formula under meteorological conditions for the detection object of the single index online detector. If the error is within the set range, the output of all the index data in the soil gas by the meteorological monitor is used as the result output; When the error between the two exceeds the set range, the inspection and correction process begins; The inspection and correction process is to add an additional sampling and testing process; And use the actual results to correct the fitting curve and / or the difference fitting curve under meteorological conditions; The sixth step is to express the soil gas content. The soil gas content is measured by calculating the mean of the dynamically changing data. The temperature value, temperature value or air pressure value of the whole year of the monitoring year or the previous year is used as the input object, and a data group with the same number or a multiple of the number of days in the year is output. The data group is averaged and the calculated value is used as the soil gas content representation value.

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