Sampling method and sampling pipe unit for sample

Abstract

To provide a sampling method and a sampling pipe unit for a sample capable of preventing dropout and disturbance of a sample upon pulling out a sampling pipe.SOLUTION: A sampling method for a sample 4 comprises steps of: penetrating, adjacent to a sampling pipe 3, an inflow passage forming member 6 in a column pile shape into an objective ground 1; then forming an inflow passage 7 by pulling out the inflow passage forming member 6; and pulling out the sampling pipe 3 from the objective ground 1 after introducing fluid 10 on an upper part of the objective ground 1 into the inflow passage 7, thereby being capable of preventing dropout and disturbance of the sample 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for collecting a sample and a sampling tube unit used for quality control of materials such as calcium-modified soil that is put into water as a filling material for shallow fields and tidal flats.

Background Art

[0002] A large amount of sediment generated by dredging in harbors and the like is effectively utilized as a filling material for shallow fields and tidal flats by mixing a calcium-modifying material with adjusted particle size and composition of converter steel slag to form calcium-modified soil (see, for example, Patent Document 1).

[0003] In the quality control of this calcium-modified soil, a sample is prepared by filling a mold with the material immediately after mixing the calcium-modifying material with the sediment, and the sample is evaluated by conducting a uniaxial compression test or the like.

[0004] In addition, when the calcium-modified soil is put into water as a filling material for shallow fields and tidal flats, it may be necessary to evaluate the strength of the material after being put into water. In that case, as shown in FIG. 5, a cylindrical sample collection tube 31 is inserted into the target ground 30 immediately after the calcium-modified soil is put into water, and after hardening, the sample collection tube 31 is pulled out from the target ground 30 to collect the sample 32 taken into the sample collection tube 31, and the sample is evaluated by conducting a uniaxial compression test or the like (see, for example, Non-Patent Document 1). Note that reference numeral 33 in the figure is the water surface.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the conventional technology as described above, as shown in FIG. 5, when the sampling tube 31 is pulled out, a vertical hole 34 is formed, resulting in a negative pressure. Due to this negative pressure, a part 32a of the sample 32 taken into the sampling tube 31 may be pulled out, and there is a risk that a part 32a of the sample 32 may fall into the vertical hole 34.

[0007] In addition, the water above the target ground 30 is drawn into the vertical hole 34 by the water 35 flowing through the inside of the sampling tube 31 and the water 36 flowing outside the sampling tube 31. Among them, the sample 32 may be cracked by the water 35 flowing through the inside of the sampling tube 31, and the sample 32 may be disturbed.

[0008] Therefore, in view of such conventional problems, the present invention is made for the purpose of providing a sample collection method and a collection tube unit that can prevent the sample from falling off or being disturbed when the sampling tube is pulled out.

Means for Solving the Problems

[0009] The feature of the invention according to claim 1 for solving the conventional problems as described above is that a sampling tube with both ends open is penetrated into the target ground, and the sampling tube is pulled out to collect the sample taken into the sampling tube from the target ground. In the sampling method, after the sampling tube is penetrated into the target ground, a column pile-shaped inflow path forming member is penetrated into the target ground adjacent to the sampling tube, and then the inflow path forming member is pulled out to form an inflow path. After drawing in the fluid above the target ground into the inflow path, the sampling tube is pulled out from the target ground.

[0010] The feature of the invention according to claim 2 lies in a method for sampling a sample, which involves driving a sample collection tube with both ends open into the target ground, and extracting the sample taken into the sample collection tube from the target ground by pulling out the sample collection tube. In this method, after driving a columnar pile-shaped member for forming an inflow path into the target ground, the sample collection tube is driven into the target ground adjacent to the member for forming the inflow path, and then the member for forming the inflow path is pulled out to form an inflow path. After drawing in the fluid above the target ground into the inflow path, the sample collection tube is pulled out from the target ground.

[0011] The feature of the invention according to claim 3 lies in a method for sampling a sample, which involves driving a sample collection tube with both ends open into the target ground, and extracting the sample taken into the sample collection tube from the target ground by pulling out the sample collection tube. In this method, after driving a sampling tube unit, which is detachably unitized with a columnar pile-shaped member for forming an inflow path in a state where the sample collection tube and the member for forming the inflow path are adjacent to each other, into the target ground, the member for forming the inflow path removed from the sampling tube unit is pulled out from the target ground to form an inflow path. After drawing in the fluid above the target ground into the inflow path, the sample collection tube is pulled out from the target ground.

[0012] The feature of the invention according to claim 4, in addition to the configuration of claim 3, is that the sampling tube unit includes a guide tube integrated adjacent to the sample collection tube, the member for forming the inflow path inserted into the guide tube in a withdrawable manner, and a means for preventing withdrawal for holding the lower end of the member for forming the inflow path in a state where it protrudes deeper than the lower end of the sample collection tube in the guide tube. After driving the sampling tube unit into the target ground, the main body of the member for forming the inflow path is withdrawn from the guide tube to form the inflow path in the target ground.

[0013] The feature of the invention according to claim 5, in addition to the configuration of any one of claims 1 to 3, is that the lower end of the member for forming the inflow path is driven into the target ground until it reaches a position deeper than the lower end of the sample collection tube.

[0014] The feature of the invention according to claim 6 is that, in addition to the configuration of any one of claims 1 to 3, at least one of the plurality of sample collection tubes is penetrated in a state of being adjacent to the member for forming the inflow path, and the plurality of sample collection tubes are penetrated into the target ground in a state of being adjacent to each other. After forming the inflow path by pulling out the member for forming the inflow path from the target ground, the sample collection tube adjacent to the member for forming the inflow path is pulled out from the target ground, and the hole formed by pulling out the adjacent sample collection tube is used as a new inflow path, and the other sample collection tube adjacent to the inflow path or the new inflow path is pulled out.

[0015] The feature of the invention according to claim 7 is that, in addition to the configuration of any one of claims 1 to 3, an inwardly projecting anti-drop member is provided on the inner peripheral surface of the lower end of the sample collection tube.

[0016] The feature of the invention according to claim 8 is a sampling tube unit configured to collect a sample taken into the sample collection tube from the target ground by pulling out the sample collection tube penetrated into the target ground, the sample collection tube having both ends open. The sampling tube unit includes a guide tube integrated adjacent to the sample collection tube, a pile-shaped member for forming an inflow path inserted into the guide tube so as to be extractable, and a means for preventing the member for forming the inflow path from coming out by holding the member for forming the inflow path in the guide tube in a state where the lower end of the member for forming the inflow path protrudes deeper than the lower end of the sample collection tube.

[0017] The feature of the invention according to claim 9 is that, in addition to the configuration of claim 8, the upper end portion of the member for forming the inflow path is provided with a connecting portion to which a wire for pulling out can be connected.

Advantages of the Invention

[0018] The method for collecting a sample according to the present invention can suppress the negative pressure acting when pulling out the sample collection tube from the target ground and prevent the sample from dropping and being disturbed from the sample collection tube by having the configurations described in claims 1 and 2.

[0019] Also, in the present invention, by providing the configuration described in claim 3, the sample collection tube and the member for forming the inflow path can be simultaneously penetrated into the target ground.

[0020] Furthermore, in the present invention, by providing the configuration described in claim 4, the sample collection tube and the unitized member for forming the inflow path can be easily pulled out.

[0021] Furthermore, in the present invention, by providing the configuration described in claim 5, fluid can be reliably introduced from the inflow path into the hole formed when pulling out the sample collection tube, and the generation of negative pressure can be suppressed.

[0022] Furthermore, in the present invention, by providing the configuration described in claim 6, when installing the sample collection tubes over a wide range, by installing only one member for forming the inflow path, each sample collection tube can be stably pulled out in a chained manner.

[0023] Furthermore, in the present invention, by providing the configuration described in claim 7, in addition to the effect of preventing the sample from falling off due to negative pressure suppression, it is possible to physically prevent the sample from falling off from the sample collection tube.

[0024] Also, the collection tube unit according to the present invention can unitize the sample collection tube and the member for forming the inflow path by providing the configuration described in claim 8, and can easily pull out the member for forming the inflow path from the target ground.

[0025] Furthermore, in the present invention, by providing the configuration described in claim 9, the member for forming the inflow path can be easily pulled out from the target ground using the extraction wire.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying out the Invention

[0027] Next, embodiments of the sample collection method according to the present invention will be described based on the examples shown in FIGS. 1 to 3. In the figure, reference numeral 1 is the target ground filled with a landfill material, reference numeral 2 is the water surface, and reference numeral 3 is a sample collection tube for collecting a sample 4 used for inspecting strength etc. from the target ground 1.

[0028] In this example, a case where calcia-modified soil obtained by mixing a calcia modifier with adjusted particle size and composition of steelmaking slag into a large amount of soft soil generated by dredging in a harbor etc. is used as a material will be described as an example. However, the object of collection is not limited to the case where calcia-modified soil is used, and any material that exhibits a certain strength may be used. For example, cement-solidified treated soil etc. may be used.

[0029] As shown in FIGS. 1 and 3, the sample collection tube 3 is composed of a vinyl chloride tube or a steel tube and is formed in a cylindrical shape with both ends open.

[0030] The size of this sample collection tube 3 is not particularly limited. For example, those with a diameter of 50 mm to 100 mm and a total length (length in the tube axis direction) of about 2 m are used. The total length of the sample collection tube 3 can be appropriately set according to the situation of the target ground. When the ground made of the calcia-modified soil is buried by other materials (for example, sand covering), the total length obtained by adding the thickness of the other materials is used.

[0031] In addition, an inwardly projecting anti-drop member may be provided on the inner peripheral surface of the lower end portion of the sample collection tube 3 so that the sample 4 taken into the sample collection tube 3 is retained inside the sample collection tube 3 by the anti-drop member and is physically difficult to drop off. Note that the anti-drop member is not necessarily provided.

[0032] The anti-drop member is not particularly limited. As shown in Fig. 3(a), for example, it is formed by triangular plate materials 5a, 5a... Each anti-drop member 5a, 5a... may be fixed by welding, an adhesive, bolts, etc. according to the materials of the sample collection tube 3 and the anti-drop member 5a, 5a... with the acute angle side facing downward and at intervals in the circumferential direction of the inner peripheral surface.

[0033] Alternatively, as shown in Fig. 3(b), the anti-drop member may be constituted by bolts 5b, 5b... that penetrate from the outside at intervals in the circumferential direction and project inside the lower end portion of the sample collection tube 3, and the bolts 5b, 5b... may be fixed by tightening nuts 5c.

[0034] Furthermore, as shown in Fig. 3(c), the anti-drop member 5d may be formed in an annular shape, an arc shape, or a C shape, and the annular anti-drop member 5d or the like may be fitted to the lower end portion of the sample collection tube 3 and fixed to the inner peripheral surface by welding, an adhesive, bolts, etc.

[0035] To collect the sample 4 using this sample collection tube 3, while the strength of the calcia-modified soil is low immediately after the calcia-modified soil is put into water, as shown in Fig. 1(a), the pile-shaped inflow path forming member 6 is penetrated into the target ground 1 adjacent to the sample collection tube 3. Then, as shown in Figs. 1(b) to 1(c), the inflow path forming member 6 is pulled out to form the inflow path 7. After drawing in the fluid 10 such as seawater above the target ground 1 into the inflow path 7, as shown in Fig. 1(d), the sample collection tube 3 is pulled out from the target ground 1 at a predetermined time to collect the sample 4 taken into the sample collection tube 3.

[0036] As shown in FIGS. 1(a) to 1(c), the member 6 for forming the inflow path is formed in a pile shape using a vinyl chloride pipe, a steel pipe, or the like.

[0037] In addition, it is desirable that the total length of the member 6 for forming the inflow path is longer than the total length of the sample collection pipe 3 because the lower end penetrates to a position deeper than the lower end of the sample collection pipe 3.

[0038] Here, the pile shape includes a cylindrical shape such as a cylinder having a pressing portion 8 at the lower end, a columnar shape such as a cylinder, a pile shape, a body formed by bundling a plurality of small-diameter (for example, 20 mm or less) cylindrical bodies into one pile shape, etc. The material constituting the member 6 for forming the inflow path is not limited to the above-mentioned pipe materials such as vinyl chloride pipes and steel pipes, and may be a solid rod-shaped wood, metal material, or resin material.

[0039] Further, the pressing portion 8 is not limited to a flat surface or a plate shape forming the lower end surface. For example, it may be formed in a conical shape or a polygonal pyramid shape with a pointed lower end so as to easily penetrate into the target ground 1. In addition, when the member 6 for forming the inflow path is cylindrical and the inner diameter is small (20 mm or less), the pressing portion 8 may not be provided at the lower end.

[0040] As shown in FIG. 1(a), the installation of the sample collection pipe 3 and the member 6 for forming the inflow path penetrates into the target ground 1 until the lower end of the member 6 for forming the inflow path reaches a position deeper than the lower end of the sample collection pipe 3. In addition, the lower end position of the member 6 for forming the inflow path only needs to be deeper than the lower end position of the sample collection pipe 3 by a depth equivalent to the diameter of the member 6 for forming the inflow path. For example, when the diameter of the member 6 for forming the inflow path is 100 mm, it may be about 100 mm deeper than the lower end of the sample collection pipe 3.

[0041] When corresponding to a plurality of sample collection tubes 3A, 3B or sample collection tubes 3A to 3F with a single inflow path forming member 6, as shown in FIGS. 2(b) and 2(c), the plurality of sample collection tubes 3A to 3F are adjacent to each other, and the inflow path forming member 6 is arranged so as to be adjacent to at least one of the plurality of sample collection tubes 3A to 3F (3A to 3C in FIG. 2(c)) and penetrate into the target ground 1. It should be noted that the sample collection tubes 3A to 3F are assigned the symbols 3A to 3F respectively according to the order of extraction for convenience.

[0042] In addition, as shown in FIG. 2(d), it is also possible to arrange a large number of sample collection tubes 3A to 3F so as to surround the inflow path forming member 6 arranged in the center. However, when pulling out the inflow path forming member 6, it is necessary for the fluid 10 to flow into the lower end (tip) of the inflow path forming member 6. Along with this, since the water channel is formed around the inflow path forming member 6, there is a high possibility that any one or a plurality of the sample collection tubes 3A to 3F surrounding the inflow path forming member 6 will be disturbed. Therefore, it is desirable to arrange the inflow path forming member 6 at the end and reduce the number of sample collection tubes 3, 3 adjacent to the inflow path forming member 6 to reduce the probability of disturbance in the sample collection tubes 3, 3 adjacent to the inflow path forming member 6.

[0043] The penetration operation of the sample collection tube 3 and the inflow path forming member 6 into the target ground 1 can be carried out in accordance with the conventional general penetration operation of the sample collection tube, and can be penetrated using an existing device for installing the sample collection tube.

[0044] The order of installation of the sample collection tube 3 and the inflow path forming member 6 may be such that the sample collection tube 3 is first penetrated into the target ground 1, and then the inflow path forming member 6 is penetrated along the sample collection tube 3 adjacent to the sample collection tube 3 into the target ground 1. Alternatively, the inflow path forming member 6 may be first penetrated into the target ground 1, and then the sample collection tube 3 may be penetrated along the inflow path forming member 6 adjacent to the inflow path forming member 6 into the target ground 1.

[0045] Also, when installing a plurality of sample collection tubes 3A to 3F, it is desirable to make the overall lengths of the respective sample collection tubes 3A to 3F different, and to adopt the sample collection tube 3 with a longer overall length in order from the one with the earlier extraction order. In Fig. 2(c), the overall length of the inflow path forming member 6 is the longest, and the overall lengths of the sample tubes 3A, 3B, and 3C are longer than the overall lengths of the sample tubes 3D, 3E, and 3F. Incidentally, since the inflow path 7 has already been formed adjacent at the time of extraction, the overall lengths of the sample tubes 3A, 3B, and 3C may be the same length, and the sample tubes 3D, 3E, and 3F may have the same overall length since new inflow paths 7A, 7B, and 7C have already been formed adjacent at the time of extraction.

[0046] Then, after the installation of the sample collection tube 3 and the inflow path forming member 6 is completed, at a desired time after a certain strength has been developed such that the surrounding calcia-modified soil does not collapse and the inflow path 7 can be formed even when the inflow path forming member 6 is pulled out from the calcia-modified soil as shown in Figs. 1(b) to (c), basically, in accordance with the timing of pulling out the sample collection tube 3 (or the first sample collection tube 3A in the case of multiple tubes), the inflow path forming member 6 is pulled out from the target ground 1 to form a vertical hole-shaped inflow path 7 adjacent to the sample collection tube 3.

[0047] At that time, by pulling out the inflow path forming member 6, a vertical hole-shaped inflow path 7 is formed under the inflow path forming member 6 in the target ground 1, and seawater, which is the fluid 10, is drawn in and filled into the inflow path 7 from the upper part of the target ground 1.

[0048] Also, this inflow path 7 is formed deeper than the lower end of the adjacent sample tube, and is filled with a fluid 10 such as seawater drawn to the lower end.

[0049] Then, as shown in Fig. 1(d), the sample collection tube 3 adjacent to the inflow path 7 filled with the fluid 10 such as seawater is pulled out at a desired time, and the sample 4 taken into the sample collection tube 3 is collected. The desired time for pulling out the sample collection tube 3 is not particularly limited, and it may be after a long period such as one year or two years has passed.

[0050] At this time, the side of the vertical hole 9 formed by pulling out the sample collection tube 3 is in communication with the adjacent inflow path 7, and the fluid 10 such as seawater flows into the vertical hole 9 from the inflow path 7. Since the water pressure is balanced and stabilized in the vertical hole 9 formed under the sample collection tube 3, a large negative pressure does not occur in the vertical hole 9 when the sample collection tube 3 is pulled out. Also, since the water above the target ground 1 can be prevented from flowing into the vertical hole 9 through the inside of the sample collection tube 3, it is possible to prevent the sample 4 taken into the sample collection tube 3 from falling off due to negative pressure, and it is possible to prevent the sample 4 from being disturbed by the water above the target ground 1 flowing into the hole through the inside of the sample collection tube 3.

[0051] In addition, as shown in FIGS. 2(b) and 2(c), when a plurality of sample collection tubes 3A to 3F are installed, after first pulling out the inflow path forming member 6 installed at the end to form the inflow path 7, the sample collection tube 3A adjacent to the inflow path forming member 6 is pulled out. Then, the hole formed by pulling out the adjacent sample collection tube 3A is used as a new inflow path 7A, and the other sample collection tubes 3B adjacent to the inflow path 7 or the new inflow path 7A are pulled out in succession.

[0052] For example, in the case shown in FIG. 2(c), when the sample collection tube 3A adjacent to the inflow path forming member 6 is pulled out from the target ground 1, the vertical hole formed by pulling out the adjacent sample collection tube 3A is used as a new inflow path 7A, and the other sample collection tubes 3B and 3C adjacent to the inflow path 7 or the inflow path 7A can be sequentially pulled out. The sample collection tube 3D that is not in contact with the inflow path forming member 6 can be pulled out using the vertical hole formed by pulling out the sample collection tube 3A or 3C as a new inflow path 7A or 7C. In this embodiment, for convenience, the sample collection tube 3A is pulled out first, but the sample collection tube 3B symmetrically arranged with the sample collection tube 3A may be pulled out first. In that case, the sample collection tubes 3B, 3A, and 3C are pulled out in that order.

[0053] Similarly, when pulling out each sample collection tube 3E that is not adjacent to the member 6 for forming the inflow path, the vertical holes formed by pulling out the adjacent sample collection tubes 3B and 3C that have already been pulled out are used as new inflow paths 7B and 7C and pulled out. Then, the sample collection tube 3F is pulled out using the vertical holes formed by pulling out the adjacent sample collection tubes 3B, 3D, and 3E that have already been pulled out as new inflow paths 7C, 7D, and 7E. In this embodiment, for convenience, the sample collection tube 3D is pulled out first, but the sample collection tube 3E that is symmetrically arranged with the sample collection tube 3D may be pulled out first. Also, when the sample collection tube 3D or 3E is pulled out and there are two remaining sample collection tubes, either of the two remaining sample collection tubes may be pulled out first.

[0054] Regarding the extraction conditions of each sample collection tube 3A to 3F, there are no particular limitations other than pulling them out in order from the sample collection tube 3A adjacent to the member 6 for forming the inflow path described above. For example, the extraction timing may be such that each sample collection tube 3 is sequentially pulled out every long-term span of one year to verify the aging changes of the calcia-modified soil, etc. over the long-term span.

[0055] In the above-described embodiment, the case where the sample collection tube 3 and the member 6 for forming the inflow path are installed separately has been described. However, the installation of the sample collection tube 3 and the member 6 for forming the inflow path may be performed simultaneously using a collection tube unit 20 in which the sample collection tube 3 and the member 6 for forming the inflow path are unitized so as to be detachable while being adjacent to each other.

[0056] For example, an example of a method for collecting a sample using the collection tube unit 20 will be described based on FIG. 4. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0057] This sampling tube unit 20 includes a sample sampling tube 3 with both ends open, a guide tube 21 integrated adjacent to the sample sampling tube 3, a member 6 for forming an inflow path that is removably inserted into the guide tube 21, and a means for preventing the member 6 for forming an inflow path from coming out while the lower end of the member 6 for forming an inflow path protrudes to a position deeper than the lower end of the sample sampling tube 3. The sample sampling tube 3 and the member 6 for forming an inflow path are detachably unitized via the guide tube 21.

[0058] The guide tube 21 is formed in a cylindrical shape with both ends open and having the same diameter as or a smaller diameter than the sample sampling tube 3. Its overall length is shorter than that of the sample sampling tube 3, and the lower end position is at the same position as or higher (shallower) than the lower end of the sample sampling tube 3. It is fixed to the sample sampling tube 3 in an adjacent state.

[0059] The fixing means of the guide tube 21 is not particularly limited. For example, the sample sampling tube 3 and the guide tube 21 may be tied together with a binding band or the like, or fixed with an adhesive or the like.

[0060] The member 6 for forming an inflow path is configured in the same manner as in the above-described embodiment, and is formed in a pile shape with an outer diameter slightly smaller than the inner diameter of the guide tube 21 using a vinyl chloride tube, a steel pipe, or the like.

[0061] In addition, the member 6 for forming an inflow path has a length such that, while being held by the guide tube 21 by the means for preventing it from coming out, its lower end protrudes from the guide tube 21 to a position deeper than the lower end of the sample sampling tube 3.

[0062] Also, the upper end portion of the member 6 for forming an inflow path is provided with a connecting portion (not shown) to which a pulling wire (not shown) is connected, and it can be pulled out from the guide tube 21 by pulling the pulling wire.

[0063] The form of the connecting portion is not particularly limited. For example, it may be provided with an insertion hole penetrating in the diameter direction at the upper end portion of the member 6 for forming an inflow path.

[0064] The extraction prevention means is not particularly limited as long as it can hold the member 6 for forming the inflow path in the guide pipe 21 so that it cannot be extracted. For example, it may include a diametrical through-hole 22 provided at a predetermined position of the guide pipe 21 and a rod 23 that penetrates through the through-hole 22 in a withdrawable manner, and the upper end surface of the member 6 for forming the inflow path may be brought into contact with the rod 23 to prevent extraction. Although not particularly shown, it may also be constituted by a cap that screws onto the upper end portion of the guide pipe 21.

[0065] To collect a sample using this sampling tube unit 20, first, as shown in Fig. 4(a), the sampling tube unit 20 is penetrated into the target ground 1.

[0066] At that time, the member 6 for forming the inflow path is held in the guide pipe 21 in a state where the lower end of the member 6 for forming the inflow path protrudes deeper than the lower end of the sample collection tube 3 by the extraction prevention means. Specifically, the member 6 for forming the inflow path is penetrated into the target ground 1 together with the sample collection tube 3 by taking a reaction force on the rod 23 constituting the extraction prevention means, and as shown in Fig. 4(b), the member 6 for forming the inflow path is penetrated into the target ground 1 to a position deeper than the lower end of the sample collection tube 3.

[0067] Then, as shown in Fig. 4(c), at a desired time after a certain strength has developed in the calcia-modified soil, basically at the time of pulling out the sample collection tube 3, after pulling out the rod 23, the member 6 for forming the inflow path is pulled out from the target ground 1 from the guide pipe 21.

[0068] At that time, by pulling out the member 6 for forming the inflow path, a vertical hole-shaped inflow path 7 is formed in the target ground 1 below the guide pipe 21 and deeper than the lower end of the adjacent sample collection tube 3. Seawater, which is the fluid 10, is drawn into the inflow path 7 from the upper part of the target ground 1, and the guide pipe 21 from which the member 6 for forming the inflow path has been pulled out is filled.

[0069] Then, as shown in Fig. 4(d), the sampling tube 3 adjacent to the inflow path 7 filled with the fluid 10 such as seawater is pulled out at a desired time together with the guide tube 21, and the sample 4 taken into the sampling tube 3 is collected. The desired time to pull out the sampling tube 3 is not particularly limited, and it may be after a long period such as one year or two years has passed.

[0070] At this time, the side portion of the vertical hole 9 formed by pulling out the sampling tube 3 is in communication with the adjacent inflow path 7, and the fluid 10 such as seawater flows into the vertical hole 9 from the inflow path 7, and the water pressure is balanced in the vertical hole 9 formed under the sampling tube 3, resulting in a stable state. Therefore, when the sampling tube 3 is pulled out, a large negative pressure does not occur in the vertical hole 9, and water on the target ground 1 cannot flow into the vertical hole 9 through the inside of the sampling tube 3. Thus, it is possible to prevent the sample 4 taken into the sampling tube 3 from falling off due to negative pressure and to prevent the disturbance of the sample 4 caused by water on the target ground 1 flowing into the hole through the inside of the sampling tube 3.

[0071] Note that the sampling tube unit 20 is not limited to the above-described embodiment. For example, a pile-column-shaped inflow path forming member 6 may be detachably attached to the sampling tube 3 with a binding band or the like.

[0072] In the above-described embodiment, the target ground 1 formed by throwing a material such as calcia-modified soil into water has been described as an example, but it can also be applied to the ground in the air such as a landfill site.

[0073] In the case of application in the air, the inflow path 7 adjacent to the sampling tube 3 is filled with air as the fluid. When the sampling tube 3 is pulled out, air flows into the hole formed by pulling out the sampling tube 3 from the inflow path 7, and the air pressure is balanced in the hole formed under the sampling tube 3, resulting in a stable state.

Explanation of Reference Numerals

[0074] 1 Target ground 1 2 Water surface 3 Sampling tube 3 4 Samples 5 Anti-Detachment Member 6 Member for Forming Inflow Path 6 7 Inflow Path 8 Pressing Portion 9 Vertical Hole 10 Fluid 20 Sampling Tube Unit 21 Guide Tube 22 Through-Hole 23 Rod

Claims

1. In a method for collecting a sample by inserting a sample collection tube with open ends into a target ground and collecting the sample taken into the sample collection tube from the target ground by pulling out the sample collection tube, after inserting the sample collection tube into the target ground, a column pile-shaped inflow path forming member is inserted into the target ground adjacent to the sample collection tube, then, the inflow path forming member is pulled out to form an inflow path, after drawing in the fluid above the target ground into the inflow path, the sample collection tube is pulled out from the target ground, which is characterized in that it is a method for collecting a sample.

2. In a method for collecting a sample by inserting a sample collection tube with open ends into a target ground and collecting the sample taken into the sample collection tube from the target ground by pulling out the sample collection tube, after inserting the column pile-shaped inflow path forming member into the target ground, the sample collection tube is inserted into the target ground adjacent to the inflow path forming member, then, the inflow path forming member is pulled out to form an inflow path, after drawing in the fluid above the target ground into the inflow path, the sample collection tube is pulled out from the target ground, which is characterized in that it is a method for collecting a sample.

3. In a method for collecting a sample by inserting a sample collection tube with open ends into a target ground and collecting the sample taken into the sample collection tube from the target ground by pulling out the sample collection tube, after inserting a collection tube unit, in which the sample collection tube and the column pile-shaped inflow path forming member are detachably unitized in an adjacent state to each other, into the target ground, the inflow path forming member removed from the collection tube unit is pulled out from the target ground to form an inflow path, after drawing in the fluid above the target ground into the inflow path, the sample collection tube is pulled out from the target ground, which is characterized in that it is a method for collecting a sample.

4. The sampling tube unit includes a guide tube integrally formed adjacent to the sample sampling tube, a member for forming an inflow path that is removably inserted into the guide tube, and a means for preventing the member from coming out, which holds the member in the guide tube in a state where the lower end of the member for forming the inflow path protrudes deeper than the lower end of the sample sampling tube. The method for sampling a sample according to claim 3, wherein after the sampling tube unit is penetrated into the target ground, the main body of the member for forming the inflow path is withdrawn from the guide tube, and the inflow path is formed in the target ground.

5. The method for sampling a sample according to any one of claims 1 to 3, wherein the lower end of the member for forming the inflow path is penetrated into the target ground until it is deeper than the lower end of the sample sampling tube.

6. At least one of a plurality of sample sampling tubes is penetrated in a state adjacent to the member for forming the inflow path, and the plurality of sample sampling tubes are penetrated into the target ground in a state adjacent to each other. After the member for forming the inflow path is pulled out from the target ground to form the inflow path, the sample sampling tube adjacent to the member for forming the inflow path is pulled out from the target ground, and the hole formed by pulling out the adjacent sample sampling tube is used as a new inflow path, and the other sample sampling tube adjacent to the inflow path or the new inflow path is pulled out. The method for sampling a sample according to any one of claims 1 to 3.

7. The method for sampling a sample according to any one of claims 1 to 3, wherein an inwardly projecting anti-drop member is provided on the inner peripheral surface of the lower end portion of the sample sampling tube.

8. A sampling tube unit including a sample sampling tube having both ends open, and sampling a sample taken into the sample sampling tube from the target ground by pulling out the sample sampling tube penetrated into the target ground. A sampling tube unit, comprising: a guide tube integrated adjacent to the sample collection tube; a pile-shaped member for forming an inflow path, which is inserted into the guide tube in a withdrawable manner; and a means for preventing the member for forming the inflow path from coming out, which holds the member for forming the inflow path in the guide tube in a state where the lower end of the member for forming the inflow path protrudes to a position deeper than the lower end of the sample collection tube.

9. The sampling tube unit according to claim 8, further comprising a connecting portion at an upper end portion of the member for forming the inflow path, to which a wire for pulling out can be connected.

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