JP5789804B1 - Underground breathability inspection method and soil contamination investigation method - Google Patents

Abstract

To provide an underground air permeability inspection method capable of pinpointing an underground place where there is a high possibility that a contaminant exists. A gas pressurized to a first pressure in a pressurized container 79 is supplied to a borehole 5 penetrated to a predetermined depth F in the ground M, and is drilled at a lower end portion of the borehole 5. The gas is injected into the ground M from the exhaust hole. The pressure reduction time required until the pressure in the pressurized container 79 decreases to the second pressure lower than the first pressure from the start of the injection is measured. When the measurement is completed, the depth F with respect to the underground M of the borehole 5 is changed to another depth F. When the depth is changed, gas injection and decompression time are measured again to check the permeability of the underground M. [Selection] Figure 7

Description

  The present invention relates to an underground air permeability inspection method and a soil contamination investigation method.

  In the conventional soil contamination investigation method disclosed in Patent Document 1, ozone gas is injected into the ground through a discharge hole formed in the lower end of the ozone injection pipe through the ozone injection pipe. A gas of a volatile organochlorine compound, which is a substance to be investigated, that has flowed in from an inflow hole that has been drilled is captured and the concentration of the gas is measured.

JP 2006-349371 A

  However, in the conventional soil contamination investigation method, when there is a contaminant in the ground between the lower ends of the ozone injection pipe and the observation pipe, the contaminant is captured by the observation pipe and the concentration is measured. Although it can be measured, it was difficult to estimate from the measurement results to which point between the pipes the pollutant exists.

  The present invention has been made to solve such a problem, and provides an underground air permeability inspection method capable of pinpointing an underground place where there is a high possibility that a contaminant exists. For the purpose.

To this end, ground breathable inspection method according to the present invention, a gas sealed in a pressure vessel in a state pressurized to a first pressure, to the ground of a predetermined depth gas injecting the gas into the ground from the injection drilling pipe to the gas discharge holes formed in the lower end of the infusion necessity drilling pipe by supplying by releasing the penetration infusion for the drilling pipe An injection step; a time measurement step for measuring a depressurization time required for the pressure in the pressurized container to drop to a second pressure lower than the first pressure from the time when the gas injection step is started; and A depth changing step of changing the depth of the injecting borehole to the other depth when the time measuring step is completed, and once the depth changing step is completed, the gas injection step and the time measuring step are performed again. I will check the breathability in the ground It is obtained by the.

  The soil contamination investigation method according to the invention described in claim 2 is a soil contamination investigation method carried out in parallel with the underground air permeability inspection method according to claim 1, wherein the time measurement step is completed. In the state where the gas injection step is not performed, the gas injected into the ground by the gas injection step is sucked from the suction hole drilled in the lower end portion of the suction borehole, and the suction borehole is A gas recovery step for recovering to the ground via, and a concentration measurement step for measuring the concentration of contaminants contained in the gas recovered by the gas recovery step, wherein the suction test tube is the injection test tube When the gas recovery step is carried out, it is inserted in the vicinity of the point of penetration and at a distance from the point in the horizontal direction by a certain distance so as to be substantially parallel to the injection test tube. The suction borehole was penetrated Depth in is characterized in that it is underground depth approximately equal to setting of the injection drilling tube during the gas injection step is conducted just prior to the gas recovery step.

  The soil contamination investigation method according to the invention described in claim 3 is the soil contamination investigation method according to claim 2, wherein the ground injection point that penetrates the injection borehole into the ground or the suction borehole is grounded. A plurality of suction points on the ground penetrating into the ground, and setting a plurality of points over a certain area so that the points adjacent to each other are arranged at predetermined intervals in the horizontal direction, The other point is set at a position adjacent to each of the set one point, and the predetermined interval is set to be separated from the horizontal interval between the injection point and the suction point adjacent to each other. It is characterized by being.

  According to the first aspect of the present invention, the air permeability of the soil at the underground point penetrating the injection test tube can be accurately obtained for each depth. Based on this, it is possible to pinpoint a place in the ground where there is a high possibility that a contaminant exists.

According to the second aspect of the present invention, since the suction borehole is inserted in the vicinity of the point where the injection borehole is inserted, the gas injected through the discharge bore of the injection borehole allows the suction borehole to be Underground pollutants existing in the vicinity of the suction hole are mixed into the gas. Since the gas contaminated with the pollutant is collected by the suction test tube, the time required from the injection of the gas to the recovery of the gas mixed with the pollutant can be shortened as much as possible. As a result, the concentration of the pollutant can be quickly measured.
In addition, the gas injected into the ground is used not only for underground breathability inspection but also for measuring the concentration of underground contaminants. Concentration measurement can be performed efficiently.

  According to invention of Claim 3, the space | interval of the adjacent points between either one of the injection | pouring point which penetrates the borehole for injection | pouring into the ground, or the suction | attraction point which penetrates the borehole for suction | inhalation in the ground Is set to be separated from the interval between the injection point and the suction point adjacent to each other, so that there are not too many points to conduct underground air permeability inspection and soil contamination investigation. Can be done efficiently.

It is a front view which shows the state which looked at the borehole apparatus used when implementing the underground air permeability inspection method and soil contamination investigation method which concern on embodiment of this invention from the front. It is sectional drawing which follows the arrow AA line of FIG. It is a bottom view which shows the state which permeate | transmitted some members and was seen from the downward direction of the drilling apparatus of FIG. It is the figure which expanded and showed the lower part of FIG. It is the figure which expanded and showed the up-down direction middle part of FIG. It is sectional drawing which fractured | ruptured and showed a part of sample tube and its vicinity member. The state where the pressurized gas supply device, concentration measuring device, and control panel which are used when carrying out the underground air permeability inspection method and the soil contamination investigation method according to the embodiment of the present invention is schematically shown. FIG. It is the figure which showed the state which laid down the trial-drilling device, and was moved by rolling of a caster. It is the figure which showed typically the state which looked at the point of the ground which penetrates a plurality of boreholes from the upper part. It is a figure which shows the mode of the operation | work which pulls out a borehole from underground. It is a figure which shows the state which is going to lift and move a trial drill apparatus with a forklift. (1) The figure is a three-dimensional graph in which the decompression time measured at the same depth at each injection point of the borehole indicated by the X, Y coordinates is shown on the vertical axis. (2) The figure is the X, Y coordinates. 3 is a three-dimensional graph in which the vertical axis represents the concentration of contaminants collected at the same depth at each suction point of the borehole shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. What is shown by the code | symbol 1 in FIG. 1 is an example of the borehole apparatus used when implementing the underground air permeability inspection method and soil pollution investigation method which concern on embodiment of this invention, and mainly uses trichlorethylene and tetrachlorethylene. It is used when carrying out the air permeability inspection method and soil contamination investigation method for underground M in which the soil is contaminated with contaminants composed of volatile organic compounds (hereinafter referred to as “VOCs”). The borehole device 1 includes a frame 3, a pair of strike devices 7 and 7 for individually penetrating the pair of boreholes 5 and 5 into the ground M, and the vertical positions of the strike devices 7 individually. A pair of hydraulic cylinders 9, 9 to be adjusted, four leg members 11 fixed to the frame 3 to stand the frame 3 on the ground E, and a pair of oil pressures individually supplied to the respective striking devices 7 The hydraulic pressure supply devices 13 and 13 and a pair of hydraulic pressure supply devices 14 and 14 that individually supply pressure oil to the hydraulic cylinders 9 are provided. The pair of boreholes 5 and 5, the striking devices 7 and 7, the hydraulic cylinders 9 and 9, the hydraulic supply devices 13 and 13, and the hydraulic supply devices 14 and 14 have the same configuration.

  The frame 3 includes a pair of guide rails 15 and 15 extending in the vertical direction parallel to each other at a certain interval in the horizontal direction, and one end portion (upper end portion in FIG. 1) and the other end portion of each guide rail 15 in the longitudinal direction. A pair of first members fastened and fastened by a screw member 16 (see FIG. 2) with the guide rail 15 sandwiched between the lower end portion in FIG. Beam members 17 and 17, a pair of second beam members 19 and 19, and a pair of third beam members 21 and 21 are provided.

  Further, the frame 3 is opposed to the pair of first beam members 17 and 17 bonded to one guide rail 15 and the pair of first beam members 17 and 17 bonded to the other guide rail 15. A pair of first horizontal members 23, 23, which are horizontally mounted between the first beam members 17 and fastened by a screw member, and a pair of second beam members 19, which are bonded to one guide rail 15, 19 and a pair of second beam members 19, 19 connected to the other guide rail 15. The pair of second beam members 19, which are horizontally opposed to each other, are fastened by a screw member. The second horizontal members 25, 25 (see FIGS. 3 and 4), and a pair of the second horizontal members 25, 25 in contact with the bottom surfaces of the pair of second horizontal members 25, 25 and the bottom surfaces of the second beam members 19, respectively. The second horizontal members 25, 25 are fastened by screw members. Comprising wear has been a pair of bottom members 27 and 27. Each guide rail 15, each first beam member 17, each second beam member 19, and each third beam member 21 are made of iron members, and their cross-sectional shapes are formed in an approximately H shape. A pair of first beam members 17, 17, a pair of second beam members 19, 19, and a pair of third beam members 21, 21 are provided on both side surfaces in the center of each guide rail 15 when viewed from the direction orthogonal to the transverse section. The beam members 17, 19, and 21 are fastened and fastened by the screw members 16 in a state where the side surfaces of each of the guide rails 15 are in contact with each other.

On the side surface of each second beam member 19, an iron leg member 11 having the same structure is fastened and bound by a screw member 29. A screw hole of a female screw is formed in the lower end portion of the leg member 11, and a screw shaft 31 of a male screw is screwed into the screw hole. A handle 33 is coupled to the upper end portion of the screw shaft 31, and is attached to the lower end portion. A disk-shaped grounding member 35 is bound. By rotating the screw shaft 31 together with the handle 33, the relative position of the grounding member 35 with respect to the frame 3 can be appropriately adjusted, and the borehole device 1 can be installed upright on the ground E.
Further, casters 37 having the same configuration are fastened and bonded to the side surfaces of the first beam members 17 and the second beam members 19 by screw members. For this reason, after removing the screw member 29 and detaching each leg member 11 from the second beam member 19, the drilling device 1 is laid down in the horizontal direction so that the wheels of the casters 37 are grounded to the ground E and the wheels are rotated. By moving it, the borehole device 1 can be easily transported. At this time, each caster 37 is configured to be rotatable around a rotation axis extending in a direction orthogonal to each side surface (side surface to which each caster 37 is attached) of each first beam member 17 and each second beam member 19. Therefore, the moving direction of the borehole device 1 can be easily changed.

  Each striking device 7 is fastened and integrated by a screw member in a state where both side surfaces of the main body are sandwiched between a pair of plate-like weight plates 7a and 7a (see FIG. 5). A slider 7b is fixed to each side surface of one of the weight plates 7a. By attaching the pair of weight plates 7a, 7a, the weight of each striking device 7 increases accordingly, and the impact force when striking is improved. Each striking device 7 moves along the longitudinal direction of each guide rail 15 by sliding along the longitudinal direction of each rail portion 15a with each slider 7b holding the rail portion 15a of each guide rail 15. It is configured to be able to. Each slider 7b is made of a resin member or a metal member coated with a low friction resin member or a low friction material. Each striking device 7 is connected to a hydraulic pressure supply device 13 via a pressure oil pipe 39, and pressure oil is individually supplied from each hydraulic pressure supply device 13 to each striking device 7. Each striking device 7 has an upper end portion individually connected to an upper end portion of the piston rod 9 b of the hydraulic cylinder 9 via a wire 41. A midway portion of each wire 41 is wound around a pair of pulleys 43 fixed to the upper end portion of each guide rail 15.

  Each hydraulic cylinder 9 includes a cylinder body 9a and a piston rod 9b. The upper end and the lower end of each cylinder body 9a are connected to a hydraulic supply device 14 via pressure oil pipes 45a and 45b, respectively. Pressure oil is individually supplied from the device 14 to each cylinder body 9a. Pressure oil is supplied from the hydraulic pressure supply device 14 to the cylinder body 9a via one of the pressure oil tubes 45a and 45b, and from the cylinder body 9a to the hydraulic pressure supply device 14 via the other pressure oil tube. Is returned, the piston rod 9b advances and retreats in the vertical direction with respect to the cylinder body 9a. As the piston rod 9b moves back and forth in the vertical direction, the striking device 7 connected to the piston rod 9b via the wire 41 moves in the opposite direction to the piston rod 9b.

Each striking device 7 includes a striking device main body 49 and a striking portion 51, and each striking portion 51 has a hook-shaped fitting portion 51 a (see FIG. 6) at the lower end. The upper end portion of the cylindrical hit member 53 is fitted in each fitting portion 51a, and the upper end portion of the borehole 5 is fitted in the recess formed in the lower end portion of each hit member 53. The hit member 53 is hit by the hitting part 51 in the state where it is made. The borehole 5 is penetrated into the underground M by hitting the hit member 53.
As shown in FIG. 6, each borehole 5 includes a drilling member 55 positioned at the lower end when penetrating into the underground M, and a cylindrical first circle that is screwed and connected to the drilling member 55. A pipe 57 and a cylindrical second circular pipe 61 connected to the first circular pipe 57 via a cylindrical connecting pipe 59 are provided. As the dimensions of the first circular pipe 57 and the second circular pipe 61, for example, the outer diameter of both the circular pipes 57, 61 is set to 33.5 millimeters, the inner diameter is set to 24 millimeters, and the length of the first circular pipe 57 is set. Is set to 25 centimeters, and the length of the second circular tube 61 is set to 1 meter. The excavation member 55, the first circular pipe 57, the connection pipe 59, and the second circular pipe 61 are made of iron members.
In FIG. 6, for the convenience of drawing, the middle part in the longitudinal direction of the second circular pipe 61 is omitted.

  The excavation member 55 has a male threaded portion engraved on the outer periphery of the upper end thereof, and an excavation portion is provided at the lower end thereof. The excavation portion is formed in a stepped shape that tapers toward the lower end. A female thread portion is engraved on the inner periphery of both ends of the first circular tube 57 and the second circular tube 61, and a male thread portion is engraved on the outer periphery of both ends of the connection tube 59. The excavation member 55 and the first circular pipe 57 are connected by the male screw portion of the excavation member 55 being screwed into the female screw portion at one end of the first circular pipe 57. The other end portion of the first circular tube 57 and the one end portion of the second circular tube 61 are connected by the male screw portions of both ends of the connection tube 59 being screwed to the female screw portions of the circular tubes 57 and 61, respectively. Is done. Further, when it is desired to penetrate the borehole 5 deeper into the underground M, another second circular pipe 61 is connected to the other end of the second circular pipe 61 via another connection pipe 59 according to the depth F. A single long bore tube 5 can be constructed by connecting and connecting.

  The first circular tube 57 is provided with a plurality of through holes 57 a formed by slits that are long in the longitudinal direction of the first circular tube 57. Two through-holes 57a are formed by irradiation with two high-density laser beams at three positions in the longitudinal direction of the first circular tube 57 at regular intervals in the longitudinal direction. The two through holes 57 a drilled at the same position are drilled at positions that are symmetrical with respect to the axis of the first circular tube 57. The through holes 57a adjacent to each other in the longitudinal direction of the first circular tube 57 are formed at positions where the angular position around the axis of the first circular tube 57 is shifted by 90 degrees. As a dimension of the through hole 57a, for example, the length is set to 10 to 15 millimeters and the width is set to 0.7 millimeters.

  In each connection tube 59, a circular insertion tube 63 is inserted with both ends protruding from both ends of the connection tube 59, and connected to male threaded portions engraved on the outer periphery of each end of each insertion tube 63. By connecting the female threaded portion engraved on the inner periphery of one end of the tool 65, the connecting pipe 59, the insertion pipe 63, and the pair of connecting tools 65, 65 are integrated to form a joint member 66. End portions of the gas supply pipe 67 made of a resin material having flexibility are inserted into the other end portions of the respective connecting devices 65 in a state where the air tightness is maintained. The end portion of the gas supply pipe 67 inserted into the connection tool 65 is configured to be prevented from coming off when the outer periphery thereof is tightened by a locking part provided inside the connection tool 65. The tightening state by the locking portion is configured to be released by operating a release operation element provided on the connection tool 65. Thus, each of the plurality of insertion pipes 63, the connection tool 65, and the gas supply pipe 67 is connected to form one long gas supply pipe 69. Gas supply pipes 69 having the same configuration are respectively disposed in the two boreholes 5.

  A male threaded portion engraved at one end of a cylindrical plug member 73 is screwed into the female threaded portion at the upper end of each second circular pipe 61 located at the top when it penetrates into the ground M, The other end of each plug member 73 is fitted into a recess 53 a formed in the lower end of the hit member 53. Each hit member 53 is provided with a communication hole 53b communicating with the through hole 73a in the plug member 73. The communication hole 53b extends upward from the recess 53a and then obliquely upwards. And are opened in the outer peripheral surface of each hitting member 53.

The gas supply pipes 67 respectively disposed in the pipes of the second circular pipe 61 located at the uppermost position when each of the boreholes 5 penetrates the underground M are screwed to the upper end part of the second circular pipe 61. The plug member 73 is inserted into the through-hole 73a of the plug member 73 and the communication hole 53b of the hit member 53 fitted to the plug member 73, extends obliquely upward, and is taken out to the outside. The end portion of the gas supply pipe 67 in the gas supply pipe 69 taken out from one of the two borehole pipes 5 (the right side borehole pipe 5 in FIGS. 1 and 7) is set in advance. It is connected to a pressurized gas supply device 75 for supplying air pressurized to a high pressure. One borehole 5 for supplying pressurized air constitutes an “injection borehole” according to the present invention.
On the other hand, the lower ends of the gas supply pipes 67 of the gas supply pipes 69 located at the bottom when the boreholes 5 are inserted into the ground M are disposed in the pipes of the first circular pipes 57, respectively. There is a gap between the lower end of the gas supply pipe 67 and the upper surface of the excavation member 55.

Further, the end of the gas supply pipe 67 of the gas supply pipe 69 taken out from the other of the two boreholes 5 (the left side of the borehole 5 in FIGS. 1 and 7) is the gas supply. It is connected to a concentration measuring device 77 that measures the concentration of VOCs contained in the gas sucked through the pipe 69. This other borehole 5 for gas suction constitutes the “suction borehole” in the present invention.
As shown in FIG. 7, the pressurized gas supply device 75 is disposed in the longitudinal direction of the connecting pipe 78 and the pressurized container 79 to which the end of the gas supplying pipe 67 is connected via the connecting pipe 78. An electromagnetic valve 80, a pressurizing pump 82 connected to the pressurizing container 79 via the pressurizing air supply pipe 81, a pressure sensor 83 for detecting the pressure in the pressurizing container 79, and a pressurized air supply pipe 81. The solenoid valve 84 disposed in the middle in the longitudinal direction, the steam supply device 86 connected to the pressurized container 79 via the steam supply pipe 85, and the middle in the longitudinal direction of the steam supply pipe 85. And an electromagnetic valve 87. The shape of the pressurized container 79 may be anything as long as it can store pressurized air. For example, the pressurized container 79 can be formed in an arbitrary shape such as a rectangular parallelepiped, a cylinder, or a sphere.

The pressurizing pump 82 compresses air and supplies the pressurized air to the pressurizing container 79 through the pressurized air supply pipe 81. The water vapor supply device 86 includes a boiler 86a that generates water vapor, and a pressure adjustment valve 86b disposed on the boiler 86a. The pressure adjustment valve 86b has a function of adjusting the pressure of the water vapor supplied from the boiler 86a to the water vapor supply pipe 85 to be constant. An example of the constant pressure is a pressure of 0.1 MPa (megapascal), and the temperature of the water vapor at that time is about 80 ° C. In addition, there is a correlation between the pressure of water vapor and the temperature, and when the pressure is determined, the temperature is also determined according to the pressure.
On the other hand, the concentration measuring device 77 includes a gas-liquid separation device 89 to which an end of the gas supply pipe 67 is connected, a suction pump 93 connected to the gas-liquid separation device 89 via a connection tube 91, and a connection tube 95. A concentration measuring device 97 connected to the suction pump 93 is provided.
The electric drive device of each hydraulic pressure supply device 13, the electric drive device of each hydraulic pressure supply device 14, the electromagnetic valve 80 constituting the pressurized gas supply device 75, the electric drive device of the pressure pump 82, the pressure sensor 83, The electromagnetic valve 87, the electric drive device of the suction pump 93 constituting the concentration measuring device 77, and the concentration measuring device 97 are connected to the operation panel 99 via electric wires, respectively.

《Underground air permeability inspection method and soil contamination investigation method》
Next, a method for examining the permeability of the underground M and a method for investigating soil contamination of the underground M will be described. First, each component of the borehole device 1 and the borehole 5, the gas supply pipe 69, the pressurized gas supply device 75, the concentration measuring device 77 and other instruments are transported to the site where these methods are carried out. At the site, as shown in FIG. 8, the borehole apparatus 1 from which each leg member 11 has been removed is laid down horizontally, the wheels of the casters 37 are grounded on the ground E, and the wheels are rolled, thereby making the borehole apparatus. 1 can be easily moved to a desired location. In this way, after moving the borehole device 1 to the point of the ground E that penetrates each borehole 5, the borehole device 1 is erected at the point and each leg member 11 is attached and installed. Then, the handle 33 of each leg member 11 is appropriately rotated so that the borehole device 1 is perpendicular to the ground E, and the vertical position of the grounding member 35 is adjusted.

  In addition, the point of the ground E which penetrates each borehole 5 is set beforehand, for example, as shown in FIG. 9, the several point over the whole area | region R where soil contamination is estimated is set. In FIG. 9, the position (hereinafter referred to as “injection point”) that penetrates the test tube 5 that injects air pressurized by the pressurized gas supply device 75 into the ground M is represented by white circles. A position (hereinafter referred to as “suction point”) penetrating the borehole 5 for sucking the air injected into M is represented by a black circle. The injection points adjacent to each other are set so as to be arranged at a predetermined interval in the horizontal direction, and all the horizontal intervals are set to a constant interval D1. Suction points are respectively set at positions adjacent to these injection points, and the horizontal intervals D2 between the injection points adjacent to each other and the suction points are all set to a constant interval shorter than the interval D1. For example, the distances D1 and D2 may be set to 1 meter and 20 centimeters. On the contrary, the position of the white circle may be the suction point and the position of the black circle may be the injection point.

When the borehole device 1 is installed, a pressurized gas supply device 75, a concentration measuring device 77, and an operation panel 99 are also installed in the vicinity thereof, and they are respectively connected via electric wires.
Next, the excavation member 55 at the lower end of each borehole 5 is assembled so that one end of each gas supply pipe 69 is disposed in each borehole 5 and has a certain length. And suction point respectively. Subsequently, the operation panel 99 is operated to drive each hydraulic pressure supply device 14 to raise the piston rod 9b of each hydraulic cylinder 9 to lower each impact device 7, and to fit the impact portion 51 of each impact device 7. The hit member 53 thus formed is fitted to a plug member 73 screwed to the upper end portion of each borehole 5.
Next, the end of the gas supply pipe 67 of the gas supply pipe 69 taken out from the borehole 5 positioned at the injection point among the gas supply pipes 69 is connected to the pressurized gas supply device 75.
On the other hand, the end of the gas supply pipe 67 of the gas supply pipe 69 taken out from the borehole 5 positioned at the suction point among the gas supply pipes 69 is connected to the concentration measuring device 77.

<Intrusion to the first depth>
Next, the operation panel 99 is operated to drive each hydraulic pressure supply device 13, and the hydraulic pressure is intermittently supplied to each striking device 7 from each hydraulic pressure supply device 13. As a result, the hitting member 53 is hit by the hitting portion 51 of each hitting device 7 so that each of the boreholes 5 penetrates into the ground M. Both boreholes 5 are penetrated into the ground M at a point (a point separated by a distance D2) that is spaced apart by a certain distance in the horizontal direction so as to be substantially parallel to each other. When both the boreholes 5 are penetrated to the first depth F, which is a predetermined depth set in advance, the operation panel 99 is operated to stop the supply of hydraulic pressure by the hydraulic pressure supply devices 13 and strike the impact devices 7. Interrupt.

<Steam filling work>
Next, the operation panel 99 is operated to close the electromagnetic valves 80 and 84 of the pressurized gas supply device 75 and to open the electromagnetic valve 87, and the water vapor previously generated by the boiler 86 a is used as the water vapor supply pipe. The pressurized container 79 is filled through the line 85. The pressure of the water vapor to be filled is adjusted to be constant by the pressure adjusting valve 86b, and the pressure is set to, for example, 0.1 MPa (megapascal).
<Pressurized air filling work>
Next, the operation panel 99 is operated to close the electromagnetic valve 87 and the pressure pump 82 is operated with the electromagnetic valve 84 opened to fill the pressurized container 79 with pressurized air. The pressure in the pressurized container 79 is detected by the pressure sensor 83, and a signal corresponding to the detected pressure value is transmitted to the control device 99 a in the operation panel 99. When the pressure value corresponding to the signal received by the control device 99a reaches a preset first pressure value, the control device 99a automatically stops the pressurizing pump 82 and the electromagnetic valve 84. Is closed. As a value of the first pressure, for example, setting to 0.5 MPa (megapascal) can be mentioned.

<Decompression time measurement work>
Next, the operation panel 99 is operated to open the electromagnetic valve 80 of the pressurized gas supply device 75, and the first circle of the borehole 5 penetrating the injection point through the connection pipe 78 and the gas supply pipe 69. By supplying steam-containing air containing steam into the pipe 57, the steam-containing air is introduced into the underground M from a plurality of through holes 57a (which constitutes “discharge holes” in the present invention) of the first circular pipe 57. inject. This injection work step constitutes the “gas injection step” in the present invention. At this time, by opening the electromagnetic valve 80, the decompression time T required from when the injection operation is started until the pressure in the pressurization container 79 is reduced to the preset second pressure value is controlled. It is measured by a timer in the device 99a. This measurement work process constitutes the “time measurement process” in the present invention. The measured decompression time T is stored in a memory in the control device 99a. Examples of the second pressure value include setting to 0.3 MPa (megapascal). The air injected into the underground M is mixed with a part of the VOCs existing in the gas state among the VOCs existing in the underground M.

After the pressure in the pressurized container 79 decreases to the second pressure value, the operation panel 99 is operated to perform the above-described steam filling operation and pressurized air filling operation again.
<Density measurement work>
In parallel with the steam filling operation and the pressurized air filling operation, the operation panel 99 is operated to operate the suction pump 93 of the concentration measuring device 77, and a plurality of the first circular tubes 57 of the borehole 5 penetrated into the suction point. The gas containing the underground M air and VOCs is sucked through the through hole 57a (which constitutes the “suction hole” in the present invention) and the gas supply pipe 69, and the gas is collected on the ground. . This recovery operation process constitutes the “gas recovery process” in the present invention. The depth F of the underground M of the borehole 5 that has penetrated into the suction point when performing this recovery operation was inserted into the injection point during the gas injection operation that was performed immediately before the recovery operation. It is set to be substantially the same as the depth F of the underground pipe 5 in the underground M. The underground M water sucked together with the gas by the gas recovery is separated when passing through the gas-liquid separator 89, and only the gas is sucked through the connecting pipe 91 and the concentration is measured through the connecting pipe 95. Is sent to the device 97. The concentration meter 97 measures the concentration N of VOCs contained in the gas flowing into the concentration meter 97. This measurement work process constitutes the “concentration measurement process” in the present invention. A signal corresponding to the measurement value measured by the concentration measuring device 97 is transmitted to the control device 99a, and the measurement value is stored in a memory in the control device 99a. The concentration N is represented by the volume or mass of VOCs present in the gas per unit volume.

<Intrusion work to the next depth>
Next, by operating the operation panel 99, the hydraulic pressure is supplied from each hydraulic pressure supply device 13 to each striking device 7, the penetration operation of the borehole 5 is performed again, and the depth F added by a preset length is added. Each of the boreholes 5 is further deeply penetrated into the underground M. The operation of changing the depth F constitutes a “depth changing step” in the present invention. For example, the length added for changing the depth F is set to 50 centimeters.
<Addition work of borehole and gas supply pipe>
As the depth F through which each borehole 5 penetrates becomes deeper, the second circular pipe 61 is connected and connected through the connecting pipe 59. In the case of adding the joint, the operation panel 99 is operated to lower the piston rod 9b of the hydraulic cylinder 9 to raise the impact device 7, and then the uppermost second circular pipe 61 is screwed to the lower end thereof. The member 66 is removed from the connection pipe 59. At this time, since the end portion of the gas supply pipe 67 is inserted into the connecting device 65 on the upper end side of the joint member 66 and is tightened by the engaging portion of the connecting device 65, the connection device 65 is released. The operating element is operated to pull out the end of the gas supply pipe 67 from the connector 65.

  Since the gas supply pipe 67 is set to be longer than the second circular pipe 61, the gas supply pipe 67 is stored in a bent state as shown in FIG. ing. For this reason, since the end of the gas supply pipe 67 can be protruded to the outside from the end of the removed second circular pipe 61, the end of the protruded gas supply pipe 67 is newly added for addition. After being inserted into one connector 65 of the joint member 66, one end of the connection pipe 59 of the joint member 66 is screwed to the end of the removed second circular pipe 61. Next, one end of a new gas supply pipe 67 for addition is inserted into the other connecting member 65 of the joint member 66 for addition and one end of a new second circular pipe 61 for addition of the other end. Then, it is inserted into the tube and pulled out from the other end. The other end of the extended gas supply pipe 67 that has been pulled out is inserted into the connection tool 65 on the upper end side of the joint member 66 from which the second circular pipe 61 has been removed.

Next, after screwing the other end of the second circular pipe 61 for addition to the end of the connection pipe 59 of the joint member 66 from which the second circular pipe 61 has been removed, The other end of the connection pipe 59 of the joint member 66 screwed to the end of the removed second circular pipe 61 is screwed to one end. At this time, as the joint member 66 rotates about its axis, the gas supply pipe 67 is also rotated and twisted, but the communication hole 53b of the hit member 53 through which the gas supply pipe 67 is inserted. Since the gas supply pipe 67 can be rotated relative to the communication hole 53b, the gas supply pipe 67 is twisted in a short section. There is nothing.
Finally, the operation panel 99 is operated to raise the piston rod 9 b of the hydraulic cylinder 9 to lower the impact device 7, so that the impacted member 53 fitted to the plug member 73 at the upper end portion of the second circular pipe 61 is applied. The striking part 51 is fitted. This completes the work of adding the new second circular pipe 61, the joint member 66, and the gas supply pipe 67.

When both boreholes 5 have penetrated to the next added depth F, the operation panel 99 is operated to stop the supply of hydraulic pressure by each hydraulic supply device 13 and the impact of each impact device 7 is interrupted.
Thereafter, in the same manner, the above-described steam filling work, pressurized air filling work, decompression time measurement work, concentration measurement work and penetration work up to the next depth F are repeated, and both the test tubes 5 are deepened to the deepest target depth F. When the water vapor filling operation, the pressurized air filling operation, the decompression time measuring operation, and the concentration measuring operation at the depth F are completed, each penetrating pipe 5 that has been inserted is pulled out from the underground M.
<Pulling out the borehole>
When each of the penetrating test tubes 5 is pulled out from the ground M, as shown in FIG. 10, the F-shaped pulling tool 101 is engaged with the middle portion in the longitudinal direction of the second circular tube 61 of the test tube 5, After the end of the wire 102 connected to the end of the drawing tool 101 is connected to the weight plate 7a of the striking device 7, the operation panel 99 is operated to operate the hydraulic supply device 14, and the piston rod 9b of the hydraulic cylinder 9 is operated. It can be easily pulled out by lowering. When one second circular pipe 61 is lifted above the ground E, the second circular pipe 61, the joint member 66, and the gas supply pipe 67 are reversely operated in the procedure reverse to the above-described work of adding the borehole and the gas supply pipe. Then, the remaining part of the borehole 5 remaining in the underground M is similarly pulled out by the pulling tool 101.

<Movement work of borehole device>
When the pulling-out operation of each borehole 5 is completed, as shown in FIG. 11, the borehole apparatus 103 is moved by the forklift 103 while being kept upright. At this time, by supporting the lower ends of the four third beam members 21 constituting a part of the frame 3 of the borehole device 1 by the pair of fork portions 103a and 103a of the forklift 103, the borehole device 1 can be easily kept upright. Therefore, the working efficiency is improved accordingly.
In this manner, the injection point and the suction point are changed by moving the borehole device 1, and each operation described above is repeated.
When all the above-described operations at each injection point and each suction point in the region R are completed, the operations according to the underground M air permeability inspection method and the soil contamination inspection method are completed.
As a result of performing the above-described operation, the decompression time T at each injection point in the region R and the concentration N of VOCs at each suction point are graphed for each depth F of the underground M, so that The contamination status due to VOCs can be estimated.

(1) in FIG. 12 is a three-dimensional graph showing the decompression time T measured at the same depth F at each injection point in the partial region S in the region R in FIG. Thus, the longer the decompression time T is, the longer the pressure is on the vertical axis. (1) The position of the white circle in the figure is represented by matching the position of the X and Y coordinates of the white circle in the region S in FIG. On the other hand, FIG. 12 (2) is a three-dimensional graph in which the concentration N of VOCs measured at the same depth F is plotted on the vertical axis at each inhalation point in the region S in FIG. The higher the position is, the higher the vertical axis is. (2) The positions of the black circles in the figure are represented by matching the positions of the X and Y coordinates of the black circles in the region S in FIG. Since the injection point and the suction point are adjacent to each other, assuming that the two points are substantially coincident with each other, the decompression time T and VOCs at each point are shown in FIGS. 12A and 12B. The correlation with the concentration N of N is known. By creating these three-dimensional graphs for each depth F, it is possible to three-dimensionally estimate the contamination status of the underground M.
By the way, VOCs usually pass through the gap between the aquifer formed by the presence of a lot of rocks, large and small stones, gravel and sand in the ground together with the groundwater, and the aquifer and the clay existing below it. Many stay in the silt layer interposed between the layers. Since the decompression time T described above becomes longer in the order of the aquifer, silt layer, and clay layer, the silt layer in which a large amount of VOCs is likely to stay from the decompression time T measured by the decompression time measurement operation described above. As a result, it is possible to pinpoint the position of the underground M where there is a high possibility that a large amount of VOCs stays.

According to the underground air permeability inspection method according to the embodiment of the present invention as described above, it is possible to accurately know the soil air permeability at each depth F at the point of the underground M penetrating the borehole 5. Therefore, it is possible to pinpoint the location of the underground M where there is a high possibility that the pollutant VOCs are present based on the obtained soil permeability data.
Further, since the suction test tube 5 is inserted in the vicinity of the point where the injection test tube 5 is inserted, the high-temperature steam-containing air injected through the through hole 57a of the injection test tube 5 is used for suction. The VOCs in the underground M present in the vicinity of the through hole 57a of the borehole 5 are vaporized and mixed into the water vapor-containing air. Then, since the air mixed with the VOCs is collected by the suction test tube 5, the time required to recover the air mixed with the VOCs after injecting the steam-containing air is made as short as possible. As a result, the concentration N of VOCs can be measured quickly.
In addition, since the steam-containing air injected into the underground M is used not only for the underground M breathability test but also for measuring the concentration of VOCs in the underground M, in parallel with the underground M breathability test. Thus, the concentration N of VOCs can be measured efficiently.

  Furthermore, the interval between adjacent points between any one of the injection point where the injection borehole 5 penetrates into the ground M or the suction point where the suction borehole 5 penetrates into the ground M is set. Since the distance between the injection point and the suction point adjacent to each other is set apart, it is not necessary to increase the number of underground breathability inspections and soil contamination investigations. Can be done automatically.

The embodiment of the present invention described above is an example for explaining the present invention, and the present invention is not limited to the above-described embodiment, and the invention can be read from the whole of the claims and the specification. As long as it does not contradict the gist or idea of the present invention, it can be changed as appropriate, and the underground air permeability inspection method and soil contamination investigation method after such change are also included in the technical scope of the present invention.
For example, in the above-described embodiment, an example in which the pressurization pump 82 and the water vapor supply device 86 are provided and pressurized air and high-temperature water vapor are injected into the underground M has been shown. The water vapor supply device 86 may be eliminated and only pressurized air may be injected into the underground M. In this case, the temperature of the air may be room temperature, but air heated to a high temperature by a heater may be injected. Note that it is easier to vaporize VOCs in the underground M when supplying not only air but also high-temperature water vapor, but a part of the VOCs existing in the underground M exists in a gaseous state, so that gas The concentration N can be measured by the concentration measuring device 97 by sucking the VOCs together with air and collecting them on the ground.
Further, as the gas to be injected, an inert gas such as nitrogen gas may be used instead of air.

5 Borehole 57a Through hole (discharge hole, suction hole)
79 Pressurized container D1 Interval D2 Interval F Depth M Ground N concentration T Depressurization time

Claims (3)

The gas of the gas sealed in the first pressurized vessel with pressurized state to a pressure, the injection borehole tube by releasing into the ground of a predetermined penetration has been injected for the drilling pipe to a depth a gas injection step of injecting the gas into the ground from the discharge hole formed in the lower end of the infusion necessity drilling tube by supplying,
A time measuring step of measuring a depressurization time required for the pressure in the pressurized container to drop to a second pressure lower than the first pressure from the time when the gas injection step is started;
When the time measurement step is completed, a depth changing step for changing the depth of the injection test tube to the depth to the other depth, and
An underground permeability test method in which the gas injection process and the time measurement process are performed again after the depth changing process is completed to check the underground permeability. A soil contamination investigation method that is carried out in parallel with the underground air permeability inspection method according to claim 1,
After the time measurement step is completed, the gas injected into the ground by the gas injection step is sucked from the suction hole drilled in the lower end portion of the suction borehole without performing the gas injection step. And a gas recovery step of recovering to the ground via the suction borehole,
A concentration measurement step for measuring the concentration of contaminants contained in the gas recovered by the gas recovery step,
The suction borehole is substantially parallel to the injection borehole in the vicinity of a point where the injection borehole is penetrated and at a certain distance from the point in the horizontal direction. Intruded,
The depth of the underground through which the suction borehole when the gas recovery step is performed is the depth of the underground of the injection borehole at the time of the gas injection step performed immediately before the gas recovery step. A soil contamination investigation method characterized by being set to be substantially the same as the depth. In the soil contamination investigation method according to claim 2,
One of a ground injection point that penetrates the injection borehole into the ground and a ground suction point that penetrates the suction borehole into the ground, the adjacent points between the points are horizontal. Set a plurality over a certain area so as to be arranged at predetermined intervals in the direction,
The other point is set at a position adjacent to each of the set one point,
The soil contamination investigation method, wherein the predetermined interval is set to be separated from a horizontal interval between the injection point and the suction point adjacent to each other.

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