JP5920739B1 - Ground sampling device and ground sampling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ground sampling device and a ground sampling method capable of collecting three phases of solid, liquid and gas from the ground as a sample in a state close to the original ground, mainly for liquefaction investigation ground. . A sampler head attached to the tip of a rod in a ground sample collection device for collecting a ground sample in the sample storage tube by lowering the sample storage tube in the axial direction at the bottom of a borehole drilled in the ground A square tubular penetration tube having an upper end fixed or slidably attached to the sampler head, a shoe having an outer taper fixed to the lower end of the penetration tube, and a lower end fixed to the shoe. A sample storage tube provided through a gap between the inner wall surface of the penetration tube and a gap between the inner wall surface of the penetration tube and the sample storage tube. The ground sample collection device is composed of a thin shutter that can seal a ground sample inserted into the sample storage tube and a liquid discharge means that can discharge the liquid inside the sample storage tube. is doing. [Selection] Figure 1

Description

  The present invention mainly relates to a liquefaction study ground, and relates to a ground sampling device and a ground sampling method that can collect three phases of solid, liquid, and gas from the ground as a sample in a state close to the original ground.

  The main ground for liquefaction is loose or medium-consolidated unconsolidated granular material (sandy / gravel), and a saw-shaped cylindrical catcher is used to prevent the sample from falling off or flowing out during sampling. The method disclosed in Patent Document 1 has been developed and put into practical use for maintaining the quality of a sample and preventing dropping in a state where a radial gap is formed but is almost closed by being pressed into the lower end of the sample while being bent. However, in the case of fine non-adhesive soil particles, especially when fine non-adhesive soil particles are bent, the conventional method of press-fitting into the lower end of the sample while bending a saw-shaped cylindrical catcher can cause fine-grained soil to flow out of the catcher gap is there.

  On the other hand, according to Patent Document 2, a circular cylinder is usually press-fitted into the ground, and then the opening is closed by drawing a shutter made of a flexible plate with a wire. Although a method for preventing the sample from falling is described, no examples in the literature have been reported.

  In the sandy ground that is the target of liquefaction, the liquefaction strength increases when the saturation level is slightly less than 100% (the air is mixed in), so the aeration method has been devised as a countermeasure against liquefaction. (Example: Patent Document 3). For this reason, there has been a demand for the in-situ saturation, but there is no established method yet.

  The freezing method has been partially performed instead of the normal temperature sampling as described above. However, when the ground temperature is lowered from normal temperature to 0 ° C., the bubbles in the pore fluid are reduced, and the saturation is increased by the volume. Further, when the gap fluid at 0 ° C. is frozen, substances other than H 2 O are discharged from the freezing front. The bubbles vary depending on the shape of the soil particles, but the discharge amount is indefinite because the bubbles adhere to the sharp points. Furthermore, the accuracy of measuring the degree of saturation is unknown because water expands by 1/11 minutes due to freezing. However, in the indoor liquefaction strength test, the standard for testing after the saturation level is set to 100% is focused on the skeleton of the soil particles, and there is a background that the frozen sampling sample has been made high-quality and saturated. There is a wrong case where freeze sampling is recommended even for degree measurements.

Patent Document 4 proposes a room temperature method that focuses on the fact that the original position and the water retention state are not changed. However, the degree of expansion of the pore fluid under the groundwater surface and the expansion rate due to the pressure of air and water differ greatly between the ground and the surface, so the saturation naturally changes even if the water retention state is maintained.
As an elemental technique for obtaining the saturation from the relationship between the volume change of the interstitial fluid and the fluid pressure, Patent Document 5 discloses a technique for deforming a metal membrane with fluid pressure as a method for generating volume change. Widely used. On the other hand, as a method for measuring the pore fluid pressure in the soil, a method in which Patent Document 6 uses a rubber disk and a gap pressure gauge with an injection needle is often used.
Regarding the method of maintaining the pressure in the collected sample, there are a method of using a viscous liquid as an encapsulated lubricant and a sample lifting method in water using a flexible hose in Patent Document 1.

Japanese Patent Laid-Open No. 03-295922 Japanese Patent Laid-Open No. 11-71744 JP 2001-193048 A JP 2014-29297 A Japanese Patent Laid-Open No. 3-189537 Japanese Patent Laid-Open No. 56-500581

  In view of the above-mentioned conventional drawbacks, the present invention has a soil particle skeleton of a quality close to that of the original ground even when the sampler is lifted, even if the sample is a soft / loose ground sample that is likely to fall out of the sample storage tube. An object of the present invention is to provide a ground sampling device and a ground sampling method capable of reliably collecting a high quality sample, and capable of reliably collecting the saturation degree of the pore fluid in a state close to the original ground.

  In order to achieve the above object, the present invention provides a ground sample collecting apparatus for collecting a ground sample in a sample storage tube by lowering a sample storage tube in the axial direction to a bottom of a borehole formed in the ground. A sampler head attached to the section, a square tubular penetration pipe having an upper end fixed or slidably attached to the sampler head, a shoe having an outer taper fixed to the lower end of the penetration pipe, The lower end of the shoe is fixed to the shoe, and the sample storage tube provided between the inner wall surface of the penetration tube and a gap between the inner wall surface of the penetration tube and the sample storage tube is operated. A thin plate shutter that sometimes protrudes from the inner wall surface of the shoe in a stepwise manner to seal the ground sample inserted into the sample storage tube, and a liquid discharge means that can discharge the liquid inside the sample storage tube Constitute a panel sampling device.

As is clear from the above description, the present invention has the following effects.
(1) In the invention of claim 1, since the plurality of thin plate shutters block the lower end of the sample storage tube from the left and right, the fine-grained soil does not fall off or flow out.
(2) Since it has liquid discharge means that can discharge liquid from the sample storage tube, even if muddy water or the like is accumulated at the bottom of the borehole, it can be discharged from the liquid discharge means when the sample storage tube is press-fitted. And can be collected in its original state.
(3) The invention of claim 2 can achieve the same effects as in the above (1) and (2), and supply a viscous liquid to the double shutter at the lower end of the sample so that a pressure equivalent to the gap pressure in the sample is obtained. Since pressurization can be performed, the saturation can be measured at the above-ground part of the borehole while the gap pressure of the sample is maintained.
(4) The invention of claim 3 also provides the same effects as in the above (1) to (3), and even if the bottom of the borehole is rough due to boring and the degree of saturation is different from the original ground, the upper part of the sample In addition, a ground sample near the bottom of the borehole can be isolated by pressing the shutter, and a ground sample close to the original shape between the upper thin plate shutter and the lower thin plate shutter can be obtained.
(5) The invention of claim 4 can achieve the same effects as the above (1) to (4), and can measure the degree of saturation in the ground without pulling up the ground sampling device.

The process drawing of the 1st form for carrying out the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view of the ground sampling apparatus of the 1st form for implementing this invention. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. Explanatory drawing of the sample storage tube insertion process of the 1st form for implementing this invention. Explanatory drawing of the ground sample sealing process of the 1st form for implementing this invention. Explanatory drawing of the pressurization process of the 1st form for implementing this invention. Process drawing of the 2nd form for implementing this invention. The longitudinal cross-sectional view of the ground sampling apparatus of the 2nd form for implementing this invention. Explanatory drawing of the sample storage tube insertion process of the 2nd form for implementing this invention. Process drawing of the 3rd form for implementing this invention. The longitudinal cross-sectional view of the ground sample-collecting apparatus of the 3rd form for implementing this invention. Explanatory drawing of the sample storage tube insertion process of the 3rd form for implementing this invention. Process drawing of the 4th form for implementing this invention. The longitudinal cross-sectional view of the ground sample-collecting apparatus of the 4th form for implementing this invention. FIG. 16 is a sectional view taken along line 16-16 in FIG. 15; FIG. 17 is a sectional view taken along line 17-17 in FIG. 15; Explanatory drawing of the ground sample sealing process of the 4th form for implementing this invention. Process drawing of the 5th form for implementing this invention. The longitudinal cross-sectional view of the ground sampling apparatus of the 5th form for implementing this invention. Explanatory drawing of a saturation measuring process.

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

  In the first embodiment for carrying out the present invention shown in FIG. 1 to FIG. 7, reference numeral 1 denotes a sample storage tube 3 that is lowered in the axial direction at a bottom 2 of a borehole formed in the ground, and the ground in the sample storage tube. A ground sample collection device for collecting a sample 4. The ground sample collection device 1 includes a sampler head 6 attached to the tip of a rod 5, and a square tubular penetrating tube 7 having an upper end attached to the sampler head 6. And a shoe 8 having an outer taper fixed to the lower end portion of the penetrating tube 7, and a lower end portion fixed to the shoe 8 and provided between the inner wall surface of the penetrating tube 7 via a gap 9. A ground 9 provided in the gap 9 between the sample storage tube 3 and the inner wall surface of the penetration tube 7 and the sample storage tube 3 and protrudes in a stepped manner from the inner wall surface of the shoe during operation and inserted into the sample storage tube Thin plate shutter 1 that can seal the sample 4 10, a liquid discharge means 12 that can discharge a liquid such as muddy water from the inside of the sample storage tube 3 when the penetration tube 7 and the sample storage tube 3 penetrate the ground sample 4, and the thin plate shutters 10, 10 After the sample 4 is sealed, it is composed of a pressurizing means 13 that supplies and pressurizes the viscous liquid 11 between a plurality of thin plate shutters that protrude in steps so that the ground sample 4 has a pressure equivalent to that in the ground. .

  The penetrating tube 7 has a quadrangular cross section and is formed in a tubular shape. The upper end portion is fixed to the sampler head 6 and the lower end portion is fixed to the shoe 8.

The sample storage tube 3 has a circular cross section and is formed in a tubular shape. The upper end portion is fixed to the sampler head 6 and the lower end portion is fixed to the shoe 8.
The shoe 8 has a tapered outer shape and an inner wall that is substantially the same shape as the inner wall of the sample storage tube 3, and the inner wall surface 8 a of the shoe 8 communicates with a gap 9 between the penetration tube 7 and the sample storage tube 3. In addition, the shutter guide slits 14 and 14 for guiding the thin plate shutters 10 and 10 to seal the sample, and the shutter engagement grooves 15 and 15 are formed in the shoe inner wall surface 8a facing the shutter guide slit.

  The thin plate shutters 10 and 10 include a shutter operating head 16 movably provided in the sampler head 3, and the shutter operating head 16 can be moved up and down, and a shutter operating screw fixed to the rod 5. 17, a load transmission plate 18 fixed to the shutter operating head 16, and a thin shutter body 19 made of spring steel wider than the diameter of the sample storage tube 3 attached to the lower end of the load transmission plate 18. , 19.

  The liquid discharge means 12 is provided with a liquid passage hole 20 formed on the side surface of the sampler head 6 so as to communicate with the inside of the sample storage tube 3. When the penetration tube 7 or the like is press-fitted into the ground sample 4. A liquid such as muddy water is discharged from the liquid passage hole 20.

  The pressurizing means 13 is provided with a viscous liquid storage tank 21 for adjusting pressure in the sampler head 6, and the viscous liquid storage tank 21 is passed through a viscous liquid pressure adjusting hole 34 from a ground pressure adjusting device (not shown). By supplying the viscous liquid 11 at a predetermined pressure, the viscous liquid 11 is allowed to pass through the gap 9 and the shutter guide slit 14 to reach the inter-shutter 10a that is pressed into the ground sample 4 in a stepwise manner. The ground sample 4 inside the sample storage tube 3 is pressurized with a predetermined pressure. After the pressurization, the viscous liquid storage tank 21 is sealed in a state where the viscous liquid storage tank 21 is filled with the viscous liquid 11 in order to prevent the viscous liquid 11 from flowing backward through the gap 9 and the pressure from decreasing. It is preferable to do.

  The ground sample collection method 22 of the present invention is performed by using the ground sample collection device 1, and the ground sample collection method 22 includes the sample storage tube 3 in the bottom of the borehole 2 formed in the ground, and the sample storage tube 3. A sample storage tube insertion step 23 in which the viscous liquid 11 is supplied while being inserted therein, and a plurality of thin plate shutters 10 and 10 are press-fitted in steps below the ground sample 4 inserted into the sample storage tube 3. The ground sample sealing step 24 for sealing the inside of the storage tube 3 and the viscous liquid 11 is supplied and pressurized between the press-fitted thin sheet shutters 10 and 10 so that the sealed ground sample 4 is equivalent to that in the ground. And a pressurizing step 25 for maintaining the pressure at a predetermined pressure.

When the ground sampling device 1 of the present invention is used, the basic concept is that the penetration pipe 7 or the like is gently press-fitted into the ground for a predetermined length without rotating cutting, and the rod 5 is rotated with the vertical movement fixed. By transmitting the force to the shutter operating screw 17, the shutter operating head 16 descends together with the load transmitting plate 18, and penetrates the ground sample 4 while bending the thin plate shutters 10, 10 along the shutter guide slits 14, 14. To form a bottom lid.
At this time, the thin shutters 10 and 10 pass through the ground sample at an angle of approximately horizontal or about 45 degrees, and the shutter engaging grooves 15 formed at positions substantially opposite to the shutter guide slits 14 and 14 of the shoe inner wall surface 8a, 15 and the ground sample 4 is sealed.

  When the penetration pipe 7 or the like is press-fitted into the ground for a predetermined length, liquid such as muddy water is discharged from the liquid passage hole 20 of the sampler head 6 above the sample storage pipe 3 and replaced with the ground sample 4 as the press-fitting proceeds. The

  Note that the lower end portion of the shutter operating screw 17 is attached to a rotatable joint 26 provided in the sampler head 3 to prevent the rotational force from being transmitted to the sampler head 3 and the like.

  When the ground sample 4 is lifted to the ground, the pore fluid pressure under the groundwater surface decreases to atmospheric pressure, and the gas in the pore fluid expands and the degree of saturation is lowered. To prevent this, all spaces are deaerated. When the sample is filled with viscous liquid and the sample is taken into the inner tube, the volume of the sample, the gap between the shutter and the side wall, the gap between the sample sandwiched between the two shutters, the gap between the double pipes, the upper surface of the upper piston of the sample It is stored in the viscous liquid storage tank 21 provided in the sampler head and is configured to be pressurized with the viscous liquid from the outer periphery of the collected sample.

In addition, after collecting a ground sample with the ground sampling apparatus 1 and the ground sampling method 22 of the present invention, the volume of the pore fluid is changed under the same pore pressure as the original ground, and the volume change of soil particles and water is ignored. Therefore, only the volume of the gas in the gap fluid changes, and by measuring the volume change amount and the gap fluid pressure, the ratio of the gas to the gap amount can be measured from Boyle's law.
[Different forms for carrying out the invention]
Next, different modes for carrying out the present invention shown in FIGS. 8 to 21 will be described. In the description of the different embodiments for carrying out the present invention, the same components as those in the first embodiment for carrying out the present invention are denoted by the same reference numerals, and redundant description is omitted.

  The second embodiment for carrying out the present invention shown in FIGS. 8 to 10 is mainly different from the first embodiment for carrying out the present invention in that it can slide up and down inside the sample storage tube 3. The piston 27 is provided with a viscous liquid 11 filled in the space closed by the piston 27, and the viscous liquid 11 is discharged from the liquid passage hole 20 while moving the piston 27 upward when press-fitting into the ground sample 4. However, even if such a ground sample collection device 1A and a ground sample collection method 22A are used, the liquid discharge means 12A for replacing the viscous liquid 11 and the ground sample 4 and the sample storage tube insertion step 23A are used. The same effect as the first embodiment for carrying out the above can be obtained.

  The piston 27 is provided so as not to fall by a minute step (not shown) provided on the shoe inner wall surface 8a.

  The third embodiment for carrying out the present invention shown in FIGS. 11 to 13 is mainly different from the second embodiment for carrying out the present invention in that the liquid is communicated with the viscous liquid reservoir 21. A liquid discharge means 12B and a sample for providing the passage hole 20 and supplying the viscous liquid 11 from the viscous liquid storage tank 21 to the inside of the sample storage pipe 3 and discharging it to the viscous liquid storage tank 21 to replace the viscous liquid 11 and the ground sample 4 Even in the case of using the ground sample collection device 1B and the ground sample collection method 22B, the same operational effects as those of the first embodiment for carrying out the present invention can be obtained in that the storage tube insertion step 23B is used.

  The fourth embodiment for carrying out the present invention shown in FIGS. 14 to 18 is mainly different from the second embodiment for carrying out the present invention in that the upper portion of the sample storage tube 3A formed in a rectangular tube shape. Are provided with upper thin plate shutters 28, 28 so as to protrude from the shutter guide slits 14, 14, and the ground sample is moved up and down by the thin plate shutters 10, 10 and the upper thin plate shutters 28, 28. Even if such a ground sample collection device 1C and ground sample collection method 22C are used, the same effect as that of the first embodiment for carrying out the present invention is obtained in that the ground sample sealing step 24A is sealed. It is done.

  Further, in the upper part of the sampling sample, that is, in the vicinity of the bottom of the hole, the gap fluid is also affected by the circulating fluid during boring and is often different from the original shape, but the ground sampling device and the ground sampling method of the present embodiment are used. By pressing the shutter into the upper part of the sample, the ground sample 4 (ground sample close to the original shape) between the shutter and the lower part of the sample can be obtained, and only this ground sample can be used for the test. I can do it.

  The fifth embodiment for carrying out the present invention shown in FIGS. 19 to 21 is mainly different from the fourth embodiment for carrying out the present invention in that a gap pressure gauge 29 is provided on the inner wall of the sample storage tube 3. A metal membrane 30 is mounted on the opposite inner wall, fluid is supplied to the membrane 30 through a hose 31 from a ground pressure regulator (not shown), and the membrane is adjusted by increasing or decreasing the fluid pressure. Saturation measurement that changes the volume of the gap and changes in the gap pressure at the measurement depth, and enables measurement without the influence of coincidence of internal and external pressure and change of ground temperature. The ground sample collection device 1D and the ground sample collection method 22D according to the present invention are provided with the device 32, and the saturation measurement step 33 is performed after the pressurization step. Like the form In addition to obtaining the effects, the ground sample collection device 1D of the present invention is press-fitted into the investigation ground, then the membrane 30 is pressurized, and the saturation measurement device 32 measures the saturation, thereby storing the sample in the ground sample collection device 1D. The degree of saturation can be measured without lifting the ground sample 4 collected inside the tube 3 to the ground.

  In the embodiment of the present invention, the form in which the pressurizing process is performed has been described. However, the present invention is not limited to this, and even if a ground sample is collected without performing the pressurizing process, a plurality of sheets protrude in a different manner. The ground sample 4 inserted in the sample storage tube can be reliably collected without dropping the ground sample 4 by the thin plate shutters 10 and 10 capable of sealing.

  In the embodiment of the present invention, the shutter operating head 16 is moved down by the shutter operating screw 17 to operate the thin shutter 10, but the present invention is not limited to this, and the shutter operating head is driven by water pressure. The thin plate shutter 10 may be operated by lowering 16, or the thin plate shutter 10 may be operated by applying a load to the shutter operating head 16.

  INDUSTRIAL APPLICABILITY The present invention is used in industries that perform various laboratory tests in the in-situ state of the ground that is likely to fall off and flow out, liquefaction strength tests in the original ground state, and saturation measurement before and after liquefaction measures.

1, 1A, 1B, 1C, 1D: Ground sampling device,
2: Boring hole bottom 3, 3A: Sample storage tube,
4: Ground sample, 5: Rod,
6: Sampler head, 7: Penetration tube,
8: shoe, 9: gap
10: Thin plate shutter, 11: Viscous liquid,
12, 12A, 12B: Liquid discharging means,
13: Pressurizing means, 14: Shutter guiding slit,
15: Shutter engaging groove, 16: Shutter operating head,
17: Screw for shutter operation,
18: Load transmission plate, 19: Thin plate shutter body,
20: liquid passage hole, 21: viscous liquid reservoir,
22, 22A, 22B, 22C, 22D: ground sampling method,
23, 23A, 24B: Sample storage tube insertion step,
24, 24A: Ground sample sealing process,
25: Pressurization process, 26: Rotary joint,
27: Piston, 28: Upper thin plate shutter,
29: Pore pressure gauge, 30: Membrane,
31: Hose, 32: Saturation measuring device,
33: Saturation measurement step 34: Viscous fluid pressure adjustment hole.

Claims (4)

A sampler head attached to the tip of a rod and a sampler head in a ground sample collection device for collecting a ground sample in the sample storage tube by lowering the sample storage tube in the axial direction at the bottom of a borehole formed in the ground A square tubular penetration tube having an upper end attached to the head, a shoe having an outer taper fixed to the lower end portion of the penetration tube, and a lower end portion fixed to the shoe, between the inner wall surface of the penetration tube Provided in a gap between the sample storage tube provided through the gap and the inner wall surface of the penetrating tube and the sample storage tube. A ground sample collection apparatus comprising: a thin shutter capable of sealing the inserted ground sample; and a liquid discharging means capable of discharging the liquid inside the sample storage tube. A sampler head attached to the tip of a rod and a sampler head in a ground sample collection device for collecting a ground sample in the sample storage tube by lowering the sample storage tube in the axial direction at the bottom of a borehole formed in the ground A square tubular penetration tube having an upper end attached to the head, a shoe having an outer taper fixed to the lower end portion of the penetration tube, and a lower end portion fixed to the shoe, between the inner wall surface of the penetration tube Provided in a gap between the sample storage tube provided through the gap and the inner wall surface of the penetrating tube and the sample storage tube. The thin plate shutter that can seal the inserted ground sample, the liquid discharge means that can discharge the liquid inside the sample storage tube, and after the ground sample is sealed with the thin plate shutter, the ground sample is the same as in the ground Soil sampling device, characterized in that is constituted by a pressurizing means for pressurizing and pressure supply viscous liquid between the plurality of thin plates shutter projecting manner different levels a pressure. In a ground sample collection device for collecting a ground sample in the sample storage tube by lowering the sample storage tube in the axial direction to the bottom of the borehole drilled in the ground, the ground sample collection device is attached to the tip of the rod A sampler head, a square tubular penetration tube having an upper end attached to the sampler head, a shoe having an outer taper fixed to the lower end of the penetration tube, and a lower end fixed to the shoe, the penetration tube A sample storage tube provided between the inner wall surface of the shoe and a sample storage tube between the inner wall surface of the penetration tube and the sample storage tube. A thin plate shutter that protrudes in a stepwise manner from the vicinity of each section and can seal the ground sample inserted into the sample storage tube, a liquid discharge means that can discharge the liquid inside the sample storage tube, and the thin plate After sealing the ground sample with a cutter, it is composed of a pressurizing means that supplies and pressurizes viscous liquid between multiple thin shutters that protrude in steps so that the ground sample has the same pressure as in the ground A ground sampling device. The ground sample collection device according to claim 2 or 3, wherein the sample storage tube includes a saturation measuring device capable of measuring the saturation of a ground sample sealed in the sample storage tube.

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