WO2003029782A1

WO2003029782A1 - Nondestructive method and device for investigating underground air, nondestructive method for controlling contamination of soil, and pressure partition used for the control

Info

Publication number: WO2003029782A1
Application number: PCT/JP2002/009942
Authority: WO
Inventors: Yoshikazu Suzuki; Tetsuya Endo; Masayuki Ogawa; Takeshi Manri; Yutaka Kaneko
Original assignee: Koken Boring Machine Co., Ltd.
Priority date: 2001-09-27
Filing date: 2002-09-26
Publication date: 2003-04-10

Abstract

A method of investigating underground air, comprising the steps of installing a pressure partition (1) having openings (4) and (5) so that the openings (4) and (5) face a ground surface (G), sampling the underground air into the pressure partition (1) by reducing a pressure in the pressure partition (1) to a negative pressure, and investigating the sampled air, wherein the pressure partition (1) is formed in an at least double structure comprising an outside pressure partition (2) and an inside pressure partition (3) and, since the underground air (20) flowing into an outside space (7) between the outside pressure partition (2) and the inside pressure partition (3) is mixed with the atmospheric air (23), the mixed air is released to the outside, and only the underground air (21) flowing into an inside space (8) on the inside of the inside pressure partition (3) is sampled and investigated.

Description

Description Non-destructive underground air survey method, survey equipment, non-destructive geological pollution purification method, and pressure bulkhead used for it

The present invention relates to a nondestructive underground air investigation method, an investigation device, a nondestructive geocontamination purification method, and a pressure bulkhead used for the method. More specifically, a geological layer to be investigated or purified is subjected to boring or the like. And survey methods that do not involve destruction of the in-situ position. Background art

For example, the geological pollution of soil and groundwater by volatile organic compounds (VOCs) such as trichloroethylene and tetrachloroethylene has become a social problem, and there is an urgent need for purification measures.

Conventionally, as techniques for investigating geological pollution, there are generally known underground air survey methods in which underground air sampling pipes and gas detection pipes are inserted into boreholes to sample ground air, and gas survey methods in which air is directly sucked into the air. Have been. However, these conventional techniques have the following disadvantages.

(1) Underground air suction using a borehole requires in-situ boring. As a result, the time from the start of construction to the completion of the survey is long, which is extremely uneconomical, including boring costs, and has a high environmental load due to in situ destructive testing.

Making a sampling hole with a simple driver also has similar disadvantages, albeit on a different scale. (2) The method using underground air suction using a drill hole requires excavation of a drill rod after drilling to a predetermined depth. For this reason, when excavating the drill port, the inflow of air into the hole disturbs the underground air, making it impossible to conduct an appropriate investigation.

(3) The method using underground air suction using a borehole is to collect underground air containing volatile gas etc. from a hole with a small area with a hole diameter of about φ10 Omm in plan. Also, when a sampling hole is made with a simple driving tool, the sampling area is very small, with a hole diameter of about 10 mm. For this reason,

It will be a “point” evaluation area, and when locating the source of geological pollution on a vast factory site, excavation surveys at many locations are required.

(4) In the gas survey method that directly sucks the atmosphere, there is a flow due to wind and the like, and the source of pollution cannot be identified.

Conventionally, the following technologies have been generally known as technologies for purifying geological pollution.

(1) A method of creating a negative pressure environment underground through polling holes to volatilize VOCs.

(2) A method in which contaminated groundwater is pumped from pumping wells, groundwater is purified by ground-based purification equipment, and the groundwater purified from the wells is returned to the ground.

(3) A method of injecting or injecting exothermic materials or exothermic chemicals into the basement and heating VOCs to promote volatilization.

(4) A method of excavating contaminated soil with a hydraulic excavator and purifying the soil with ground-based purification equipment.

(5) A purification method in which microorganisms are injected into the basement through boring holes or chemicals that promote the activity of microorganisms are used, and the activity of decomposing pollutants by microorganisms is used. However, the above conventional technologies require the installation of boreholes and wells, and excavation by hydraulic shovels, etc., and although they are for purification, all technologies involve in situ destruction. For this reason, the in situ cannot be restored to the state before contamination after purification. In addition, drilling and construction using large machines will increase purification costs.

In the case of narrow contaminated sites, large wells cannot be installed, and in many cases, pumping wells cannot be installed at the optimal locations for purification. Furthermore, in the case of groundwater pollution, the range of pollution is wide, and construction such as polluting for degradation is restricted by residential areas and roads, and it is often impossible to take appropriate purification measures. In addition, it is difficult and costly to relocate wells when it is found that the location of wells is not optimal after the start of degradation.

The present invention has been made based on the technical background as described above, and achieves the following objects.

An object of the present invention is to provide a non-destructive underground air inspection method and method which can omit a high-cost and in-situ destruction process such as boring, and can perform a low-cost, simple and reliable geological pollution inspection at any place. It is to provide a device.

Another object of the present invention is that purification can be performed without destruction of the purification site, and the environment of the construction site is not restricted, and installation, movement, and removal of the purification facility are easy. An object of the present invention is to provide a non-destructive method for remediating geological pollution which can reduce the construction cost and a pressure bulkhead used for the method. Disclosure of the invention

In order to achieve the above object, the present invention provides a pressure partition having an opening, A part facing the ground surface, a method of collecting and investigating underground air in the pressure bulkhead by making the inside of the pressure bulkhead a negative pressure, comprising: It has at least a double structure consisting of an inner pressure bulkhead, and discharges the underground air flowing into the outer space between the outer pressure bulkhead and the inner pressure bulkhead to the outside, and releases the underground air flowing into the inner space inside the inner pressure bulkhead. It is a nondestructive underground air survey method characterized by sampling and surveying.

In addition, the present invention provides a pressure bulkhead having an opening so that the opening faces the ground surface, and makes the inside of the pressure bulkhead a negative pressure to collect underground air into the pressure bulkhead and investigate. A survey device,

The pressure bulkhead has at least a double structure of an outer pressure bulkhead and an inner pressure bulkhead,

Suction means for making the outer space between the outer pressure partition and the inner pressure partition and the inner space in the inner pressure partition a negative pressure, and discharging the underground air flowing into the outer space to the outside;

Means for collecting the underground air flowing into the inner space.

The suction means is connected to a suction hole provided in the outer pressure partition, and the inner pressure partition has a communication hole communicating the outer space and the inner space. An airtight holding member is provided at the opening of the outer pressure partition to block air from flowing into the outer space. The airtight holding member is a ring-shaped elastic body attached to the opening of the outer pressure partition. The airtight holding member is a tubular body embedded in the ground. The means for collecting the underground air includes: a collection hole provided in each of the outer pressure bulkhead and the inner pressure bulkhead; and a collection pipe which is introduced into the inner space through these collection holes and sucks and collects the underground air. Be prepared. Furthermore, the present invention for achieving the above object provides a method for forming an enclosed space on the surface of a geological layer to be purified,

By suctioning air in the closed space with a suction device to make the inside of the closed space a negative pressure, a contaminant such as a volatile organic compound contained in the geological layer is sucked into the closed space,

Further, there is provided a non-destructive geological pollution purification method, wherein the sucked pollutant is sucked and discharged to the outside by the suction device.

The closed space can be formed by installing a pressure partition having an opening so that the opening faces the ground surface. Means for blocking the inflow of air into the pressure bulkhead may be provided around the opening. In this case, as means for blocking the inflow of the air, an embankment may be laid around the opening, or the opening may be buried below the ground surface.

The present invention also relates to a method for cleaning volatile organic compounds contained in the above-mentioned geological layer, wherein the opening is provided on the surface of the geological layer to be purified so that the opening faces the ground surface, and the internal pressure is reduced. A pressure barrier for aspirating contaminants,

A pressure partition used for purification of geological pollution, characterized in that an airtight holding member for blocking inflow of air is provided at an end of the opening.

The airtight holding member can be formed of a ring-shaped elastic body that can be deformed according to the shape of the ground surface. The airtight holding member may be formed of a sheet-like elastic body having a widened portion extending around the outer periphery of the opening. Further, the airtightness maintaining member may be constituted by a hard cylindrical body embedded in the geological layer. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal sectional view showing an embodiment of the method and apparatus for investigating underground air according to the present invention, FIG. 2 is a longitudinal sectional view showing a state of collecting underground air, and FIG. FIG. 4 is a diagram showing a process of collecting underground air together with a pressure state in a pressure bulkhead. FIG. 4 is a longitudinal sectional view showing an embodiment of a purification method according to the present invention. FIG. 5 is another embodiment of the purification method. FIG. 6 is a longitudinal sectional view showing still another embodiment of the purification method, FIG. 7 is a longitudinal sectional view showing a preferred embodiment of the pressure bulkhead, and FIG. FIG. 9 is a longitudinal sectional view showing another embodiment of the pressure bulkhead, and FIG. 9 is a longitudinal sectional view showing still another embodiment of the pressure bulkhead. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a nondestructive type underground air inspection device according to the present invention, in which a pressure bulkhead 1 has a double structure of an outer pressure bulkhead 2 and an inner bulkhead 3 disposed inside thereof. Both the outer pressure partition 2 and the inner pressure partition 3 have openings 4 and 5. The outer pressure bulkhead 2 and the inner pressure bulkhead 3 are installed on the ground surface G so that the openings 4 and 5 face the ground surface G. As a result, an outer space 7 between the outer pressure bulkhead 2 and the inner pressure bulkhead 3 and an inner space 8 inside the inner pressure bulkhead 3 are formed on the ground surface G, which are hermetically sealed. The opening 4 of the outer pressure bulkhead 2 is provided with an airtight member 9 for blocking the inflow of the atmosphere into the outer space 7. The airtight holding member 9 is a ring-shaped elastic body attached to the entire periphery of the opening 4. The ring-shaped elastic body is made of rubber or a polymer material which closely adheres to the unevenness of the ground surface G and exhibits a sealing function. It is desirable to provide a similar airtight holding member 10 also in the opening 5 of the inner pressure partition 3. Although not shown, a cylindrical body may be provided in the openings 4 and 5 instead of the ring-shaped elastic body as the air-tightness maintaining member, and the cylindrical body may be buried by being pushed to an appropriate depth in the ground. Thus, a sealing function can be exhibited.

The outer pressure bulkhead 2 is provided with a suction hole 11, and a suction means 13 such as a vacuum pump is connected to the suction hole 11 via a suction pipe 12. The suction pipe 12 is provided with a pressure gauge 14. The operation of the suction means 13 is controlled by a controller 15 to which the measurement signal of the pressure gauge 14 is inputted. As shown in FIG. 3, the pressure (negative pressure) in the pressure bulkhead 1 and the pressure The retention time can be set arbitrarily.

The outer pressure bulkhead 2 is further provided with a sampling hole 16 into which a below-described underground air sampling pipe is inserted, and the sampling hole 16 is closed by a plug 17 when suctioning the underground air. The inner pressure bulkhead 3 is provided with a communication hole 18 for communicating the outer space 7 and the inner space 8. These communication holes 18 also serve as underground air sampling holes.

Since the outer pressure bulkhead 2 and the inner pressure bulkhead 3 are maintained at a negative pressure, that is, a pressure lower than the atmospheric pressure, the inner pressure bulkhead 3 and the inner pressure bulkhead 3 are most preferably formed in a thin and lightweight substantially hemispherical shape having excellent buckling strength. Good, but it is also possible to use a cylindrical or square tube.

Next, a method for collecting in-situ underground air using the above-described underground air survey device will be described with reference to FIGS.

In the original position, the outer pressure bulkhead 2 and the inner pressure bulkhead 3 are installed on the ground surface G such that the openings 4 and 5 face the ground surface G. When the pressure reducing means 13 is operated in this state, the air in the outer space 7 and the inner space 8 communicating with the outer space 7 via the communication hole 18 is sucked, and the pressure in the pressure bulkhead 1 becomes negative pressure. As a result, underground air 20 and 21 flow into the outer space 7 and inner space 8, respectively. I do.

At that time, it is inevitable that the air 23 flows into the outer space 7 from the opening 4 of the outer pressure bulkhead 2 even though it has the airtightness retaining member 9, and the pressure distribution in the pressure barrier 1 ( The negative pressure distribution) is as shown by reference numeral 22. That is, the inflowing air 23 mixes with the underground air 20 flowing into the outer space 7, and such mixed air lowers the accuracy of the measurement. Released outside.

On the other hand, only the ground air 21 into which the incoming air 23 does not mix flows into the inner space 8. For this reason, the inner pressure bulkhead 3 is set sufficiently smaller than the outer pressure bulkhead 2. The size of the inner pressure bulkhead 3 is set in consideration of the size of the ground to be subjected to geological pollution at the original position and the transportability and handleability. Depending on the size of the suction means 13, for example, the diameter is Φ300. mm or more can be easily achieved.

Then, after a lapse of a predetermined time, as shown in FIG. 2, gas sampling pipes 24 are inserted into the sampling holes 17 and 18, and the underground air 21 stored in the inner space 8 is sucked and collected. As the gas sampling tube 24, a well-known gas detection tube having a gas suction hole for sucking air (gas) at the tip can be used. As described above in detail, according to the present invention, the following unprecedented excellent effects can be obtained.

(1) Compared to conventional underground air suction using a borehole, the polling process that involves high-cost destruction in situ can be omitted. For this reason, low cost, simple and reliable geological pollution survey can be performed in a short time.

(2) Since there is no inflow of air into the inner space and underground air that is not mixedly disturbed by the inflow air can be collected, a reliable geological pollution survey can be performed.

(3) The inner pressure bulkhead can be easily realized with a diameter of φ300 mm or more. The sampling area can be more than 900 to 9 times larger than that of the existing borehole with a diameter of about 100 to 100 mm. Therefore, when identifying the source of geological pollution on a vast factory site as “area assessment”, the number of surveyed sites can be significantly reduced compared to the conventional survey method, which is extremely efficient.

(4) Compared to the gas survey method that directly sucks the atmosphere, it is not affected by the flow due to wind, etc., so it is possible to conduct reliable geological pollution survey.

Next, an embodiment of the non-destructive geological pollution purification method according to the present invention will be described. FIG. 4 is a sectional view showing the same embodiment. The geological stratum 31 shown in Fig. 4 is contaminated with VOCs (indicated by reference numeral 32), and the following treatment is performed on this geological stratum 31 for purification.

In this embodiment, the pressure bulkhead 33 is a tubular member such as a cylinder or a square tube, and has an opening 34. Inside the pressure bulkhead 33, a suction pipe 38 connected to a suction device 37 such as a vacuum pump is opened. The pressure bulkhead 33 is made of a pressure-resistant material such as a stainless steel plate, but any material may be used as long as it has the pressure resistance. For example, it may be constituted by a resin plate provided with a reinforcing member on the inner circumference or the outer circumference. In addition, the shape is not limited to a cylindrical shape, but may be various shapes such as a hemisphere.

The pressure bulkhead 33 is installed on the ground surface G of the geological stratum 31 to be purified so that the opening 34 faces the ground surface G. As a result, a closed space 36 is formed on the ground surface G. By operating the suction device 37, the air inside the pressure bulkhead 33 is sucked, and the internal pressure is made lower (negative pressure) than the atmospheric pressure. As a result, the movement of fluid such as underground air in the geological layer 31 is promoted, and the underground fluid is sucked into the pressure bulkhead 33 as shown by an arrow in FIG. Along with the suction of the underground fluid, the VOCs 32 contained therein also flow into the inside of the pressure bulkhead 33, where the liquid The VOCs that existed as a volatile gas volatilize, and are discharged to the outside through the suction pipe 38.

The concentration of VOCs discharged from the suction device 37 may be measured and monitored by a concentration measuring device (not shown) to manage the progress of the purification process. Further, an adsorption device using activated carbon or the like may be connected to the suction device 37 via a pipe to adsorb VOCs. Note that the above embodiment is based on the premise that VOCs are present in the preliminary survey, but the survey is conducted using the same method as described above, that is, the existence of the VOCs is confirmed using a concentration measurement device. In addition, it is also possible to adopt a procedure in which a purification process is subsequently performed.

If the airtightness between the end surface of the opening 34 in the pressure bulkhead 33 and the ground surface 35 is insufficient, the air flows into the pressure bulkhead 33 and effectively sucks fluid such as underground air. Can not do it. FIG. 5 and FIG. 6 show an embodiment in which means for blocking the inflow of air into the inside of the pressure barrier 33 is taken. That is, the embodiment shown in FIG. 5 is an example in which an embankment 40 is laid around the opening 34 of the pressure bulkhead 33 as a means for blocking the inflow of air. The embodiment shown in FIG. 6 is an example in which an opening 34 is buried below the ground surface as a means for blocking the inflow of air.

In the above-described embodiment of the purification method, a member for maintaining airtightness is not provided in the pressure partition itself. An airtight member can be provided on the pressure bulkhead itself to block the inflow of air. Hereinafter, a preferred embodiment will be described. The embodiment shown in FIG. 7 is an example in which a ring-shaped elastic body 41 is provided as an airtight holding member at an end of an opening 34 in a pressure bulkhead 33. The ring-shaped elastic body 41 is a ring having the same shape as the shape of the opening 34, for example, a circular ring or a square ring, and has a predetermined height and a predetermined thickness which is larger than the thickness of the pressure bulkhead 33. (Dimension between the inner and outer diameters). The ring-shaped elastic body 41 is made of, for example, a flexible rubber material. When the pressure bulkhead 33 is installed, the ring-shaped elastic body 41 is deformed according to the shape of the ground surface G, and the contact area with the ground surface G increases. Therefore, airtightness is maintained between the end surface of the opening 34 and the ground surface G, and the inflow of air can be prevented, so that fluid such as underground air can be effectively sucked.

The embodiment shown in FIG. 8 is an example in which a sheet-like elastic body 42 is provided as an airtight holding member at an end of an opening 34 in a pressure bulkhead 33. The sheet-like elastic body 42 has a widened part 43 spreading around the outer periphery of the opening part 34. The sheet-like elastic body 42 is made of, for example, a flexible rubber material, similarly to the ring-like elastic body 41 shown in FIG. 7, and when the pressure bulkhead 33 is installed, the sheet-like elastic body 42 follows the ground surface G. It spreads in a disk shape (when the outer shape is circular), and a contact area with the ground surface G that is sufficiently large with respect to the thickness of the pressure bulkhead 33 is obtained.

Then, by mounting and fixing a loading body 44 such as an embankment on the spread portion 43, the spread portion 43 is brought into close contact with the ground surface G, and sufficient airtightness can be maintained. In the case of the embodiment shown in FIGS. 7 and 8, a fluid such as water is used as a sealing material at the portion of the ground surface G that comes into contact with the ring-shaped elastic body 41 or the sheet-shaped elastic body 42. It may be penetrated, which increases the adhesion to the ground surface and further increases the airtightness. The embodiment shown in FIG. 9 is an example in which a tubular body 45 is provided as an airtight holding member at the end of the opening 34 in the pressure bulkhead 33. The cylindrical body 45 is made of a hard material such as steel, and has a larger thickness than the pressure bulkhead 33. By embedding such a tubular body 45 below the ground surface, airtightness can be reliably maintained.

As described above, according to the present invention, the following excellent effects can be obtained.

(1) Since there is no need to install wells or excavate with hydraulic excavators, Does not destroy in situ geological conditions.

(2) Since there is no need to perform boring and construction using large machines, purification costs can be significantly reduced.

(3) Since a pumping well is not required, it can be used even in narrow contaminated sites. Also, since there is no construction such as polling for purification, there are no restrictions on purification measures due to residential areas and roads.

(4) Even if it is found that the installation position of the pressure bulkhead is not optimal after the purification, the installation position can be easily changed.

Claims

The scope of the claims

1. A method in which a pressure bulkhead having an opening is installed so that the opening faces the ground surface, and a negative pressure is applied to the inside of the pressure bulkhead so that underground air is collected in the pressure bulkhead and investigated. hand,

The pressure bulkhead has at least a double structure composed of an outer pressure bulkhead and an inner pressure bulkhead, and discharges underground air flowing into an outer space between the outer pressure bulkhead and the inner pressure bulkhead to the outside, and also includes a A non-destructive underground air survey method, characterized by collecting and investigating underground air that has flowed into the interior space.

2. A surveying device that installs a pressure bulkhead with an opening so that the opening faces the ground surface, and takes underground air into the pressure bulkhead by making the inside of the pressure bulkhead a negative pressure and investigates it. So,

Means for collecting the underground air flowing into the inner space.

3. The suction means is connected to the outer pressure partition, and the inner pressure partition is formed with a communication hole communicating the outer space and the inner space. Underground air survey device as described.

4. The underground air survey device according to claim 2, wherein an airtightness retaining member that blocks inflow of air into an outer space is provided at an opening of the outer pressure partition.

5. The underground air inspection device according to claim 4, wherein the airtight holding member is a ring-shaped elastic body attached to the opening of the outer pressure bulkhead.

6. The underground air survey device according to claim 4, wherein the airtight holding member is a tubular body embedded in the ground.

7. The means for collecting the underground air includes: a collection hole provided in each of the outer pressure partition wall and the inner pressure partition wall; and a collection pipe which is inserted into the inner space through the collection holes to suction and collect the underground air. 3. The underground air survey device according to claim 2, comprising:

8. After forming an enclosed space on the surface of the geological layer to be purified,

Further, a non-destructive geological pollution purification method, wherein the sucked pollutant is sucked and discharged to the outside by the suction device.

9. The non-destructive geological pollution according to claim 8, wherein the enclosed space is formed by installing a pressure bulkhead having an opening so that the opening faces the ground surface. Purification method.

10. The method for purifying nondestructive geological pollution according to claim 9, wherein a means for blocking the inflow of air into the pressure bulkhead is provided around the opening.

11. The means for blocking the inflow of the air, comprising: laying an embankment around the opening or embedding the opening below the ground surface. The method for purifying non-destructive geological pollution according to claim 1.

1 2. The opening faces the ground surface of the geological layer to be purified. A pressure barrier for sucking contaminants such as volatile organic compounds contained in the geological formation by applying a negative pressure to the inside, and an airtight seal for blocking the inflow of air into the opening. A pressure bulkhead used for purification of geological pollution, which is provided with a holding member.

13. The pressure bulkhead used for purifying geological contamination according to claim 12, wherein the airtight holding member is formed of a ring-shaped elastic body that can be deformed according to the shape of the ground surface.

14. The pressure bulkhead used for purifying geological pollution according to claim 12, wherein the airtight holding member is formed of a sheet-like elastic body having a spread portion extending around the outer periphery of the opening. .

15. The pressure bulkhead for use in purifying geological pollution according to claim 12, wherein the airtight holding member is formed of a hard cylindrical body embedded in the geological layer.