JP2010180581A - Soil sampling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soil sampling method capable of reliably sampling contaminated soil even in the case that hot points of relatively small areas are dispersed. <P>SOLUTION: A highly flexible hollow rod having a relatively small diameter is used to excavate. When a tip has reached a position to be sampled, a sampler is inserted in the inside of the rod. The rod is advanced to fill soil to be sampled in the sampler. A recovery device is used to recover the sampler. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a soil sampling technique for sampling soil in a contaminated area in the ground.

  In soil contaminated with volatile substances (VOC), there is a region (hot point) where the concentration of pollutants is high at the boundary between a water-permeable layer such as a viscous soil layer and a water-permeable layer such as a sandy soil layer. It has been found in past surveys that it often exists.

In the conventional sampling method shown in FIG. 14, for example, the drilling rod BR for investigation passes through the groundwater level Lw and the water permeable layer Gs and excavates in the vertical direction to the bottom of the hardly permeable layer Gc.
Here, in the case where the contaminated areas PV having a relatively small area are dispersed, if the excavation is not carried out so as to pass through the contaminated areas PV pinpoint, as shown in FIG. The contaminated soil in PV cannot be sampled, and the existence of the contaminated soil cannot be grasped.

The contaminated area is schematically shown in FIG. In FIG. 15, the symbol Hb indicates a portion excavated in the vertical direction by the investigation boring rod BR, and the symbol PV indicates a contaminated area. In FIG. 15, the symbol PV1 indicates a contamination region where the VOC contamination concentration is the highest, that is, a hot point, the symbol PV2 indicates a contamination region whose contamination concentration is slightly lower than the hot point PV1, and the symbol PV3 indicates a contamination region. The region with the lowest contamination concentration is shown.
In other words, in FIG. 15, the symbols PV <b> 1 to PV <b> 3 indicate the contamination concentration distribution in the contamination region.

As another conventional technique, a soil sampling device having an outer tube and a sampling inner tube, a lid portion on which a striking force acts upon driving, and a guide for regulating the driving direction has been proposed (patent) Reference 1).
However, since the related art (Patent Document 1) presupposes sampling in the vertical direction in the same manner as the sampling method shown in FIG. 14, if hot points having relatively small areas are dispersed, contamination is caused. The soil cannot be sampled.

JP 2005-82998 A

  The present invention has been proposed in view of the above-described problems of the prior art, and provides a soil sampling method capable of reliably sampling contaminated soil even when hot points having a relatively small area are dispersed. It is an object.

  The soil sampling method of the present invention includes a step of excavating using a hollow rod (2) having a relatively small diameter and high flexibility (so-called “free boring”), and the tip of the rod (2) is soiled. A step of inserting a soil sampling device (sampler 3) into the rod (2) when the position to be sampled is reached, and a soil sampling device (sampler 3) are arranged at the tip (of the rod 2) The soil sampling device (sampler 3) using the recovery device (4) and the step of filling the soil (sampler 3) with the soil to be sampled by advancing the rod (2) while maintaining the wet state ) (Withdrawn to the ground side Gf via the inside of the rod (2)).

  Here, in the step of inserting the soil sampling device (sampler 3) into the rod (2) having a relatively small diameter and high flexibility, the soil sampling device (sampler) in the rod (2) by fluid pressure. It is preferable to move 3) (Claim 2).

  Alternatively, in the step of inserting the soil sampling device (sampler 3) into the rod (2) having a relatively small diameter and high flexibility, the recovery device (4) is engaged with the soil sampling device (sampler 3). Then, it is preferable to move the soil sampling device (sampler 3) within the rod (2) by pressing with the recovery device (4).

And it is preferable that the said collection | recovery apparatus (4) is comprised so that engagement with the soil sampling apparatus (sampler 3) is possible (Claim 4).
In the present invention, in the excavation step, it is preferable to excavate the boundary between the hardly permeable layer (Gc) and the permeable layer (Gs) in the horizontal direction (Claim 5).

  Here, when excavating to a predetermined location, the gyro is inserted to the tip of the highly flexible boring rod (2), and the angle of inclination of the gyro is measured every predetermined distance, and the ground from the tip of the boring rod (2). It is preferable to pull out the gyro to the side.

According to the soil sampling method of the present invention having the above-described configuration, since free boring is used, it is possible to easily perform sampling even when there is a severe restriction on the installation location of the boring machine as in an urban area. It is.
Also, for example, using a gyro, it is possible to calculate the trajectory of pulling out the gyro within the boring rod and to grasp the position of the tip of the boring rod with high accuracy, so the position of the sampling or hot point (PV1) Can be grasped accurately.
Furthermore, since the excavation route can be set freely, it is possible to excavate and sample the boundary between the hardly permeable layer (Gc) and the permeable layer (Gs) where hot points (PV1) are easily formed. It becomes.

  According to the present invention, since the sampling is performed by excavating the boundary between the hardly permeable layer (Gc) and the permeable layer (Gs) where the hot point (PV1) is easily formed, the hot point having a relatively small area. (PV1) is dispersed, and even in the construction site where the probability of reaching the hot point (PV1) is low in the sampling performed by drilling in the vertical direction in the past, the hot point (PV1) is accurately obtained. Can reach and sample the contaminated soil.

  In addition, since sampling can be performed a plurality of times by excavation with a single boring rod, the number of excavations can be reduced and the cost for sampling can be saved.

Sectional drawing which shows the outline | summary of embodiment of this invention. The top view which shows the outline | summary of embodiment of this invention. Sectional drawing which shows the excavation process in embodiment. Sectional drawing which shows the state which the excavation process of FIG. 3 was complete | finished. Sectional drawing which shows the process of inserting a sampler. The expanded partial sectional view which shows the state by which the sampler was arrange | positioned at the rod front-end | tip. Sectional drawing which shows a sampling process. The expanded partial sectional view which shows the state with which the soil was filled in the sampler. The expanded fragmentary sectional view which shows the state which engaged the collection | recovery apparatus with the sampler. The expanded fragmentary sectional view which shows the state which has collect | recovered the sampler. Sectional drawing which shows a sampler collection | recovery process. Sectional drawing which shows the process which is sampling again. The expanded partial sectional view of the state which rearranged the sampler in the rod tip. Sectional drawing which shows the outline | summary of the conventional soil sampling. The top view which shows the outline | summary of the conventional soil sampling.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
As described above, the contaminated region PV or the hot point PV1 often exists at the boundary between the hardly permeable layer Gc and the permeable layer Gs. For this reason, in the illustrated embodiment, as shown in FIG. 1, excavation is performed using a hollow rod 2 having a relatively small diameter and high flexibility by a boring machine 1 (so-called “universal boring” or “bending”). Boring "), and excavating in a substantially horizontal direction parallel to the boundary between the hardly permeable layer Gc and the permeable layer Gs.

Prior to the construction of the illustrated embodiment, vertical drilling (not shown) is performed in advance to determine the depth at which the boundary between the hardly permeable layer Gc and the permeable layer Gs exists in the construction ground.
Then, as shown in FIG. 1, a highly flexible rod 2 was used to excavate a borehole in the horizontal direction (left-right direction in FIG. 1) along the boundary between the hardly permeable layer Gc and the permeable layer Gs. Drill boreholes (universal boring).
In FIG. 1, the code | symbol Lw has shown the groundwater level.

  As shown in FIG. 2, if the boundary between the hardly permeable layer Gc and the permeable layer Gs is drilled in the horizontal direction, compared to the case of excavating in the vertical direction as in the prior art (see FIGS. 14 and 15), The possibility that the hole H passes through the contaminated area PV or the hot point PV1 is increased. And possibility of sampling the contaminated soil Gp of the hot point PV1 will also increase.

Specific steps of sampling in the illustrated embodiment will be described with reference to FIGS.
First, as shown in FIG. 3, a boring machine 1 (a boring machine for free boring) for excavating using a highly flexible boring rod 2 is installed at an appropriate position on the ground side Gf and excavated (freely). Start boring).
Here, the installation location of the boring machine 1 may be separated from the contaminated area (hot point) PV.

In the illustrated embodiment in which the boring machine 1 can be installed apart from a point immediately above the contaminated area (hot point) PV, the prior art in which the boring machine must be installed immediately above the contaminated area PV (FIGS. 14 and FIG. Compared to 15), the degree of freedom of installation of the boring machine 1 is greater, and the construction becomes easier accordingly.
In particular, when the space for installing the boring machine 1 is small and there are many restrictions on the layout, such as in urban areas, it is very advantageous that the degree of freedom in installing the boring machine 1 is large.

Then, for example, excavation is performed up to the sampling scheduled position as shown in FIG.
Although not clearly illustrated, in FIG. 4, the depth of horizontal excavation is the depth of the boundary between the hardly permeable layer Gc and the permeable layer Gs.
In order to change the excavation direction from the state of excavating in an oblique direction as shown in FIG. 3 to the substantially horizontal direction at the boundary between the hardly permeable layer Gc and the permeable layer Gs, for example, the excavation direction adjusting member 22 of FIG. The position of the member to be adjusted) is adjusted appropriately.

Although not clearly shown, when excavating, for example, a high-pressure fluid for excavation is jetted from the tip of the highly flexible boring rod 2 to excavate the soil.
Although not shown, when excavating, it is possible to accurately grasp the excavation route and the boring rod tip position using a gyro. For example, when excavating to a predetermined location, a gyro (not shown) is inserted to the tip of the highly flexible boring rod 2, and the gyro inclination angle is measured from the tip of the boring rod 2 to the ground side Gf at every predetermined distance. Pull out. The gyro movement trajectory from the tip of the boring rod 2 to the ground side Gf can be calculated from the minute pull-out distance and the angle of inclination of the gyro, and the position of the tip of the boring rod 2 can be specified with high accuracy. is there.

When the tip of the highly flexible boring rod 2 reaches the sampling scheduled position, as shown in FIG. 5, the sampler 3 (device for sampling) is inserted into the boring rod 2 from the ground side Gf, and the boring rod 2 is drilled. Move to the tip of the rod 2.
When moving the sampler 3 to the tip of the boring rod 2, it is possible to attach the collection device 4 (sampler collection device) to the sampler 3 on the ground side Gf and press the sampler 3 with the collection device 4. is there.
In FIG. 5, the code | symbol 5 shows the winder for winding the collection | recovery apparatus 4. As shown in FIG.

  When moving the sampler 3 from the ground side Gf to the tip of the boring rod 2, fluid pressure may be applied to the sampler 3 so that the sampler 3 moves in the boring rod 2.

The state in which the sampler 3 has moved to the tip of the boring rod 2 is shown in FIG.
In FIG. 6, the sampler 3 is moved from the ground side to the tip of the boring rod 2 using fluid pressure.
Although not clearly illustrated, in the state shown in FIG. 6, the fluid pressure still acts on the sampler 3, and the sampler 3 is pressed by the fluid pressure and held at the position of the tip of the boring rod 2. Yes.

  On the other hand, when the sampler 3 is moved using the collection device 4 (FIG. 9), the sampler 3 is placed at the tip of the boring rod 2 by continuously pressing the sampler 3 with the collection device 4 ( The state shown in FIG.

With reference to FIG. 6, the detail of the front-end | tip part of the highly flexible boring rod 2 and the sampler 3 is demonstrated.
The boring rod 2 has a rod main body 21 and an excavation direction adjusting member 22 at the tip.
A step portion 213 of the rod inner diameter portion 211 is formed in the vicinity of the distal end portion of the rod main body 21, and an inner diameter portion 212 having a smaller inner diameter than the rod inner diameter portion 211 on the distal end side (left side in FIG. 6) from the step portion 213. It has become.

The distal end of the rod body 21 is formed so as to be cut obliquely, and an excavation direction adjusting member 22 is provided on the inclined end face.
In the state shown in FIG. 6, the sampler 3 is arranged in the distal end side (left side in FIG. 6) region 2 of the inner diameter portion 212 to the inner diameter portion 211 of the rod body 21.
The sampler 3 includes a sampler body 31, an annular moving member 32, and a seal member 33.

The outer diameter dimension of the sampler body 31 is smaller than the inner diameter portion 211 of the rod body 21 and is configured to be able to move smoothly in the rod body 21.
A stepped portion having a shape complementary to the step 213 in the inner diameter portion of the rod is formed at the tip of the sampler body 31. In the state shown in FIG. 6, the step portion of the sampler main body 31 and the step 213 of the rod inner diameter portion are engaged with each other, so that positioning when the sampler 3 is inserted into the tip of the boring rod 2 is configured. Yes.

The sampler body 31 is formed with a first blind hole 311 that opens to the front end side (left side in FIG. 6) and a second blind hole 312 that opens to the ground side (right side in FIG. 6).
As shown in FIG. 8, the annular moving member 32 is configured to move to the bottom 311 b of the first blind hole 311 by being pressed by the sampled soil G when the soil G is sampled. ing.

The second blind hole 312 has a small diameter part 313 and a large diameter part 314.
As will be described later with reference to FIG. 9, the distal end shaft portion 42 of the recovery device 4 is inserted into the small diameter portion 313 when the recovery device 4 recovers the sampler 3.
And the step part in the boundary of the small diameter part 313 and the large diameter part 314 is comprised so that the latch part 44 (refer FIG. 9, FIG. 10) of the collection | recovery apparatus 4 may be engaged.

In FIG. 6, by moving the boring rod 2 forward, the soil present on the left side of the tip of the rod 2 enters the sampler 3 (FIG. 7). Then, as shown in FIG. 8, the sampled soil G is filled in the first blind hole 311 of the sampler 3.
When the sampled soil G is filled into the blind hole 311, the moving member 32 is pressed by the sampled soil G and pressed against the bottom 311 b of the first blind hole 311.

As shown in FIG. 8, when the sampled soil G is filled in the first blind hole 311, as shown in FIG. 9, the recovery device 4 (sampler recovery device) is moved from the ground side Gf to the boring rod. 2 and the front end of the collection device 4 is inserted into a second blind hole 312 formed at the ground-side end portion (right end portion in FIG. 9) of the sampler 3.
When the tip of the collection device 4 is inserted into the second blind hole 312 of the sampler 3, the latch 44 at the tip of the collection device 4 expands in the large diameter portion 314 of the blind hole 312 of the sampler 3, and the latch 44 has a small diameter. It engages with a step portion at the boundary between the portion 313 and the large diameter portion 314 (FIG. 9).

In FIG. 9, the collection device 4 includes a main body part 41 having flexibility and a tip shaft part 42 having a smaller diameter than the main body part 41.
The tip 43 of the tip shaft portion 41 has a substantially truncated cone shape. A plurality of latches 44 are provided on the shaft portion 42 excluding the tip 43 of the tip shaft portion 41. The latch 44 is biased by an elastic body (not shown) so as to expand outward in the radial direction.
As described above, when the distal end of the collection device 4 is inserted into the second blind hole 312 of the sampler 3, the latch 44 expands in diameter and engages with a step portion at the boundary between the small diameter portion 313 and the large diameter portion 314. . In this state, when the recovery device 4 is pulled out to the ground side Gf as shown in FIG. 10, the sampler 3 engaged with the latch 44 at the tip of the recovery device 4 is filled with the soil G (sampled). The soil moves to the ground side Gf (see FIG. 11).

When sampling is required again, a new sampler 3 is inserted into the boring rod 2 and moved to the tip of the boring rod 2 as shown in FIGS.
And the procedure or process demonstrated in FIGS. 5-11 is repeatedly performed.

As shown in FIGS. 1 and 2, the possibility that the boring rod 2 passes through the hot point PV1 increases.
If the timing and frequency of sampling are set appropriately, the possibility of sampling the soil at the hot point PV1 increases, and the actual state of contamination can be grasped on the ground side.

  The illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Boring machine 2 ... Highly flexible boring rod / boring rod 3 ... Sampler 4 ... Recovery apparatus 5 ... Winding machine 21 ... Rod main body 22 ... Excavation direction Adjusting member 31 ... sampler body 32 ... annular moving member 33 ... sealing member 41 ... main body 42 ... tip shaft 44 ... latch 311 ... first blind hole 312 ... second blind hole G ... soil Gf ... ground side

Claims (5)

  A step of excavating using a hollow rod having a relatively small diameter and high flexibility, and a step of inserting a soil sampling device inside the rod when the tip of the rod reaches a position where the soil should be sampled. The step of filling the soil sampling device with the soil to be sampled by advancing the rod while maintaining the state where the soil sampling device is disposed at the tip, and recovering the soil sampling device using the recovery device A soil sampling method comprising a step.   The soil sampling method according to claim 1, wherein in the step of inserting the soil sampling device into the rod having a relatively small diameter and high flexibility, the soil sampling device is moved in the rod by fluid pressure.   In the step of inserting the soil sampling device into the rod having a relatively small diameter and high flexibility, the sampling device is engaged with the soil sampling device and pressed by the recovery device, thereby sampling the soil in the rod. The soil sampling method of Claim 1 which moves the apparatus for operation.   The soil sampling method according to claim 1, wherein the recovery device is configured to be engageable with a soil sampling device.   The soil sampling method according to any one of claims 1 to 4, wherein in the excavating step, a boundary between the hardly permeable layer and the permeable layer is excavated in a horizontal direction.

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