JP2015190127A - Apparatus and method for soil core sampling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for soil core sampling that allow manual soil core sampling without much labor and reduce the sampling costs.SOLUTION: A sampling tube 2 with at least the bottom end open is inserted into an external tube 3 having open upper and lower ends and is made of a material softened by moisture, and the external tube 3 is inserted into a water bottom ground 9 along with the sampling tube 2. The water bottom ground 9 that serves as a soil core sample 8 enters and fills the sampling tube 2, and the sampling tube 2 is extracted from the external tube 3 along with the soil core sample 8, after at least a part of the external tube 3 has softened by moisture.

Description

  The present invention relates to a collecting tool and a collecting method for collecting a ground core sample, and in particular, a ground core sample collecting tool capable of extracting and collecting a ground core sample manually without requiring a great deal of effort while having a simple configuration and It relates to the collection method.

  The sampling container is inserted into the ground, then pulled out, and the ground strength or the like is measured using the collected ground core sample (see, for example, Patent Document 1). In Patent Document 1, the ground is solidified soil in which excavated earth and the like and a solidifying agent are mixed and solidified, and a separation membrane is interposed between the outer peripheral surface of the sampling container and the solidified ground, and the sampling container A method has been proposed in which the solidified soil is prevented from adhering to the sample container and the sampling container is easily pulled out.

  In this method, an external force whose main component is the horizontal direction (hereinafter referred to as earth pressure) is generated in the sampling vessel from the solidified soil having fluidity before solidification, so the sampling vessel is sandwiched from the side by the solidified soil. It will be in the state. Since the solidified soil is solidified in a state where an earth pressure is generated in the sampling container, the sampling container is subjected to the earth pressure even after the solidified soil is solidified. Therefore, even if a separation membrane is interposed between the solidified soil and the sampling vessel, the friction resistance between the separation membrane and the sampling vessel pressed against the sampling vessel by this earth pressure increases, so sampling from the solidified soil A considerable amount of force is required to pull out the container.

  Even when the ground is not solidified soil, the ground pushed away when the sampling container is driven tries to return to the original position, so that the separation membrane and the sampling container receive a certain amount of external force from the ground. Therefore, it is difficult to manually pull out the sampling container that is sandwiched between the ground.

  Therefore, since it is necessary to arrange and move heavy machinery and the like for drawing out the sampling container, it requires cost and time, and this becomes an excessive burden especially when there are many sampling points.

JP-A-3-281814

  The present invention has been made in view of the above-mentioned problems, and the purpose of the ground core sample is that it is possible to extract and collect the ground core sample manually without requiring much labor, and to suppress the cost of sampling work. It is to provide a sampling tool and a sampling method.

  In order to achieve the above object, the ground core sample collecting tool of the present invention includes a sampling cylinder having at least a lower end opened, and upper and lower ends into which the sampling cylinder is inserted and inserted into the ground together with the sampling cylinder And an outer cylinder body having an opening at the portion, wherein the outer cylinder body is formed of a material that is softened by moisture.

  In the ground core sample collecting method of the present invention, a sampling cylinder having at least a lower end opened therein is inserted into an outer cylinder formed of a material that has upper and lower ends opened and softened by moisture. By inserting the outer cylinder into the ground, the ground is inserted into the sampling cylinder and filled, and after the outer cylinder is at least partially softened by moisture, the ground is filled with the sampling cylinder And extracting from the outer cylinder.

  According to the present invention, the outer cylinder inserted into the ground is gradually softened by moisture, so that there is a gap between the outer peripheral surface of the sampling cylinder inserted in the outer cylinder and the inner peripheral surface of the outer cylinder. It becomes easy to secure a gap. As a result, when the sampling cylinder is pulled out of the ground, the frictional resistance between the two is greatly reduced, so that the ground core sample can be manually removed from the ground together with the sampling cylinder while using a sampling tool with a simple configuration. It can be pulled out. Since it is not necessary to use a heavy machine or the like for extracting the ground core sample, it greatly contributes to the reduction of work costs. The more sampling points, the more remarkable the suppression effect.

  A lubricant may be interposed between the inner peripheral surface of the outer cylinder in which the sampling cylinder is inserted and the outer peripheral surface of the sampling cylinder. In this case, since the lubricant further reduces the frictional resistance between them, the ground core sample can be pulled out from the ground together with the sampling cylinder with less labor.

  A closing member for closing an annular gap between the outer peripheral surface of the sampling cylinder and the inner peripheral surface of the outer cylinder can be provided at the lower end of the outer cylinder in which the sampling cylinder is inserted. With this closing member, when the sampling cylinder and the outer cylinder are inserted into the ground, it is possible to surely prevent the earth and sand from entering the annular gap. Therefore, when the outer cylinder is softened by moisture, the gap between the inner peripheral surface of the outer cylinder and the outer peripheral surface of the sampling cylinder is more reliably secured, and the ground core sample is pulled out from the ground together with the sampling cylinder. It becomes easy.

  A gripping part protruding from the sampling cylinder can be provided at the upper end of the sampling cylinder. By using this gripping part, it becomes easy to pull out the sampling cylinder from the ground, so that the labor of the worker who performs the extraction is further reduced.

  The present invention is applied to, for example, water bottom ground. When collecting a ground core sample of the underwater ground, a diver cannot obtain a reaction force if he / she tries to pull out the collection cylinder from the ground. However, in the present invention, the frictional resistance between the outer peripheral surface of the sampling cylinder and the inner peripheral surface of the outer cylinder is greatly reduced. The cylinder can be pulled out from the ground.

  The present invention can also be applied when the ground is formed of solidified soil. In this case, before the solidified soil is solidified, the outer cylindrical body is inserted into the ground together with the sampling cylinder, and after the solidified soil is solidified, it is extracted from the outer cylindrical body together with the solidified soil filled with the sampling cylinder. .

It is a perspective view which illustrates the outline of the collection tool of the ground core sample of this invention. It is explanatory drawing which shows the longitudinal cross-section of the collection tool of the ground core sample of FIG. It is explanatory drawing which shows the bottom face of the collection tool of the ground core sample of FIG. It is explanatory drawing which illustrates the longitudinal cross-section of another embodiment of a collection tool. It is explanatory drawing which illustrates the state which inserted the collection tool of the ground core sample of this invention in the ground in a longitudinal cross-section. It is explanatory drawing which illustrates the state which cut | disconnected the lower end part of the ground core sample from the ground with a longitudinal cross-section. It is explanatory drawing which illustrates the state which has extracted the extraction cylinder from the ground with a longitudinal cross-section. It is explanatory drawing which illustrates the longitudinal cross-section of the modification of a collection cylinder.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a ground core sample collection tool and collection method of the present invention will be described based on the embodiments shown in the drawings.

  As illustrated in FIGS. 1 to 3, the ground core sample collecting tool 1 of the present invention includes a sampling cylinder 2 having at least a lower end opened, and the sampling cylinder 2 is inserted into the ground together with the sampling cylinder 2. And an outer cylindrical body 3 having opened upper and lower ends. In this embodiment, the sampling cylinder 2 has a cylindrical shape, and both the upper end and the lower end are opened. The sampling cylinder 2 can also adopt a shape such as a rectangular tube shape. In addition, a gripping portion 6 that is gripped when an operator pulls out the sampling cylinder 2 from the outer cylinder 3 is installed on the upper part of the sampling cylinder 2. The gripping portion 6 only needs to have a shape that can be gripped by an operator and pulled out of the sampling tube 2 from the outer tube 3, for example, a frame formed in an annular shape with a wire, rope, metal, or the like. It can be comprised with the rod-shaped body formed with the metal etc.

  The collection cylinder 2 only needs to be strong enough to be pushed into the ground and inserted. For example, a polyvinyl chloride pipe, other resin pipes, or metal pipes can be used. The sampling cylinder 2 may have a cylindrical shape with the upper end closed. In this case, it is desirable to form a deaeration hole for releasing the pressure inside the sampling cylinder at the upper end portion or side surface of the sampling cylinder 2 that is closed. It is good also as a structure which installs the lid etc. which were comprised so that removal was possible in order to close the upper end part of this collection cylinder 2. FIG.

  The length of the sampling cylinder 2 in the axial direction is, for example, 500 mm to 1500 mm, the inner diameter is 50 mm to 125 mm, and the thickness of the peripheral wall is 4 mm to 7 mm.

  The outer cylinder 3 has a strength that can be inserted by being pushed into the ground, but is formed of a material that is softened by moisture. In this embodiment, the outer cylinder 3 is formed using paper that is softened by moisture. If a commercially available cardboard pipe called a void pipe is used as the outer cylindrical body 3, the sampling tool 1 can be produced at low cost. Alternatively, the outer cylinder 3 can be formed by using a water-soluble powder as a material and pressing and compacting the powder. The outer cylindrical body 3 has a cylindrical shape, but a shape such as a rectangular tube shape can also be adopted.

  The length of the outer cylinder 3 in the axial direction is, for example, 500 mm to 1500 mm, and is substantially the same as that of the sampling cylinder 2. The inner diameter of the outer cylinder 3 is, for example, 75 mm to 150 mm, and the thickness of the peripheral wall is, for example, 2.5 mm to 3.5 mm.

  In this embodiment, the diameters of the sampling cylinder 2 and the outer cylinder 3 are determined so that a gap 4 is formed between the outer peripheral surface of the sampling cylinder 2 and the inner peripheral surface of the outer cylinder 3. When the lubricant L is interposed in the gap 4, the size of the gap 4 in the radial direction is set to 0.5 mm to 8.0 mm, and the lubricant L is filled or applied to the gap 4. The lubricant L is selected to have a viscosity that does not flow out of the gap 4. For example, when the gap 4 is wider than 3.0 mm, gel-like grease or the like is used as the lubricant L, and when it is 3.0 mm or less, liquid lubricating oil or the like is used.

  It is also possible not to interpose the lubricant L in the gap 4. Alternatively, the outer peripheral surface of the sampling cylinder 2 and the inner peripheral surface of the outer cylinder 3 may be brought into close contact with each other without providing the gap 4 so that the sampling cylinder 2 is fitted into the outer cylinder 3.

As illustrated in FIG. 3, at least a part of the lower end portion of the gap 4 that is annular in plan view is covered with the closing member 5. In FIG. 3, for the sake of explanation, some of the blocking members 5 are indicated by broken lines. In this embodiment, the closing member 5 is composed of a plurality of adhesive tapes attached at the lower end of the outer cylinder 3 so as to cover the lower end of the gap 4 from the outer cylinder 3 to the sampling cylinder 2. The closing member 5 can be constituted by a plate-like member such as a plastic plate instead of the adhesive tape, or can be constituted by an annular iron plate, a plastic plate or a paperboard covering the annular lower end portion of the gap 4. The closing member 5 may be configured to cover at least a part of the annular lower end portion of the gap 4, but is desirably configured to completely cover the gap 4. Further, the closing member 5 may be integrated with the outer cylinder 3 as well as a separate body separable from the outer cylinder 3.

  The sampling cylinder 2 can be fixed to the outer cylinder 3 with the closing member 5 so that the sampling cylinder 2 does not fall out of the outer cylinder 3 before the sampling tool 1 is inserted into the ground. In this embodiment, since the lower end portion of the outer cylindrical body 3 and the lower end portion of the sampling cylinder 2 are fixed by the closing member 5 made of an adhesive tape, the sampling cylinder 2 is fixed so as not to fall out of the outer cylinder 3. .

  Instead of installing the blocking member 5, a fixing member 7 for fixing the sampling cylinder 2 to the inside of the outer cylinder 3 may be separately installed as illustrated in FIG. 4. The fixing member 7 extends from the upper part of the outer peripheral surface of the sampling cylinder 2 toward the outer cylinder 3 and supports the sampling cylinder 2 so that it does not fall downward by contacting the upper end of the outer cylinder 3. It has the composition to do. The fixing member 7 can be configured by, for example, a bolt that is screwed substantially horizontally toward the outer peripheral surface of the sampling cylinder 2, and an outer end portion such as a bolt that is opposite to the side screwed into the sampling cylinder 2 is In order to avoid contact with the ground or the like, it is desirable that the outer cylindrical body 3 is located inside the outer peripheral surface.

  The gripping part 6 may be fixed to the sampling cylinder 2 by connecting the gripping part 6 made of a wire or the like to the bolt or the like. If the sampling tube 2 can be fixed inside the outer tube 3 by friction generated between the sampling tube 2 and the outer tube 3, the fixing member 7 is not installed. May

  Next, the ground core sample collecting method of the present invention will be described by taking as an example the case of recovering the ground core sample from the submerged ground that has been ground improved using the solidified soil. The water bottom ground 9 illustrated in FIG. 5 is formed of solidified soil in which excavated earth and the like and a solidifying agent are mixed for ground improvement. The ground core sample collection tool 1 is inserted into the water bottom ground 9 before the water bottom ground 9 formed of the solidified soil is solidified. When the fluidity of the solidified soil before solidification is high and soft, the diver inserts the sampling tool 1 into the bottom bottom ground 9 by human power.

  As a result, the solidified soil before solidifying from the lower end opening of the sampling cylinder 2 enters and is filled and held in the sampling cylinder 2 as the ground core sample 8. The outer cylinder body 3 is inserted into the water bottom ground 9 while pushing the solidified soil to the side.

  At this time, the closing member 5 prevents a part of the solidified soil before solidifying from entering the gap 4. Thereby, it is possible to reliably prevent the collection cylinder 2 from being fixed to the outer cylinder 3 and not coming out of the outer cylinder 3 due to the solidified soil that has entered the gap 4.

  The solidified soil pushed away by the inserted outer cylinder 3 generates a great earth pressure on the outer cylinder 3, but this earth pressure is supported by the outer cylinder 3. The earth pressure hardly works.

  During the curing period of the solidified soil, the outer cylinder 3 absorbs surrounding water and softens gradually. At this time, the earth pressure acting on the outer cylinder 3 acts as a force for pushing the softened outer cylinder 3 toward the central axis. However, since the solidified solidified soil has almost no fluidity, no earth pressure is generated in the sampling cylinder 2.

After the outer cylindrical body 3 is softened, the diver holding the gripping portion 6 as illustrated in FIG. 6 moves the sampling cylinder 2 so that the upper end approaches and separates from the outer cylindrical body 3 with the lower end thereof as the center. Swings horizontally. Since the outer cylindrical body 3 is softened, the outer peripheral surface of the sampling cylindrical body 2 can be shaken to the vicinity of the outer peripheral surface of the outer cylindrical body 3 (or the vicinity of the outer peripheral surface before being softened). Due to this swinging, stress concentrates on the lower end portion of the ground core sample 8 held in the sampling cylinder 2 to cause breakage, and the ground core sample 8 is cut off from the water bottom ground 9. Even if the entire outer cylinder 3 is not softened, this operation can be performed in a partially softened state as long as the sampling cylinder 2 can be swung.

  For example, when the distance from the outer peripheral surface of the sampling cylinder 2 to the outer peripheral surface of the outer cylinder 3 is about 20 mm and the axial length of the sampling cylinder 2 is about 1000 mm, the sampling cylinder 2 has its central axis C Is swung to the left and right with respect to the perpendicular H by about ± 1 °. The angle of this swing is defined by the length from the outer peripheral surface of the sampling cylinder 2 to the outer peripheral surface of the outer cylinder 3 and the length of the sampling cylinder 2.

  The sizes of the sampling cylinder 2 and the outer cylinder 3 are desirably determined so that the swing angle is in the range of 0.5 ° to 2.5 °. Preferably, it is determined to be in the range of 0.8 ° to 1.5 °. As the swing angle increases, the lower end portion of the ground core sample 8 becomes easier to separate from the water bottom ground 9, and as the swing angle decreases, the sampling tool 1 to be inserted into the water bottom ground 9 becomes smaller with respect to the ground core sample 8 to be collected. The force required to insert the is reduced. In addition, the direction and swing length (swing width) of swinging the sampling cylinder 2 are appropriately determined according to the state of the water bottom ground 9.

  As illustrated in FIG. 7, the ground core sample 8 from which the lower end portion is cut is extracted from the outer cylinder 3 together with the collection cylinder 2 by human power. At this time, a sufficient space according to the thickness of the softened outer cylindrical body 3 is secured between the bottom bottom ground 9 and the outer peripheral surface of the sampling cylindrical body 2. Little affected by earth pressure generated. As a result, the frictional resistance between the outer peripheral surface of the sampling cylinder 2 and the inner peripheral surface of the outer cylinder 3 is greatly reduced. The ground core sample 8 can be extracted from the submarine ground 9 with little effort. When the gap 4 is formed between the sampling cylinder 2 and the outer cylinder 3, the gap between the water bottom ground 9 and the outer peripheral surface of the sampling cylinder 2 becomes larger, and is generated in the sampling cylinder 2. Since the earth pressure is further reduced, the frictional resistance between the sampling cylinder 2 and the outer cylinder 3 can be further reduced.

  Therefore, a heavy machine or the like for pulling out the sampling cylinder 2 is not necessary, and the cost and time required for the sampling operation can be greatly reduced. When the blocking member 5 is configured so as to be separated from the sampling cylinder 2 and remain on the outer cylinder 3 side when the sampling cylinder 2 is pulled out from the outer cylinder 3, the blocking member 5 moves with the sampling cylinder 2. It can prevent that the malfunction which increases the resistance at the time of pulling out the extraction | collection cylinder 2 in contact with the outer cylinder 3 and the water bottom ground 9 can be prevented.

  For example, when three ground core samples 8 are collected from five locations in a range of 20 m × 40 m, conventionally, a heavy machine such as an offshore crane is moved, and the jigs suspended from the offshore crane and the sampling driven into the underwater ground 9 are used. Since the diver connected the vessel, and it was necessary to pull out the sampling vessel with an offshore crane after waiting for the diver's signal, the time and cost required for the sampling work were tremendous. However, if the sampling tool 1 of the present invention is used, the diver need only to sequentially extract the sampling cylinder 2 from the outer cylinder 3 and collect it without using a heavy machine. Less expensive.

As illustrated in FIG. 8, the sampling cylinder 2 may have a configuration having an upper lid 10 that covers the upper end portion and a lower lid 11 that covers the lower end portion. After the collection tool 1 is inserted into the seabed ground 9, the diver puts the upper lid 10 on the upper surface of the collection cylinder 2. After the sampling cylinder 2 is pulled out from the outer cylinder 3 together with the ground core sample 8, the diver installs the lower lid 11 at the lower end of the sampling cylinder 2. The ground core sample 8 held in the collection cylinder 2 is transported to the water by a diver while being protected by the upper lid 10 and the lower lid 11. Therefore, it is possible to avoid the trouble that the ground core sample 8 is inadvertently dropped from the collection cylinder 2 during transportation. Further, when the ground core sample 8 held in the collection cylinder 2 is transported from the water to a test site where a strength test or the like is performed, the collection cylinder 2 having the upper lid 10 and the lower lid 11 may be used as it is as a transport container. it can.

  When the water bottom ground 9 is not solidified soil, the sampling tool 1 is inserted into the water bottom ground 9 using a heavy machine such as an offshore crane. The outer cylindrical body 3 inserted while pushing away the earth and sand constituting the water bottom ground 9 to the side absorbs the surrounding water and gradually softens. The earth pressure acting on the outer cylinder 3 at this time acts as a force to push the softened outer cylinder 3 back toward its central axis, but the fluidity of the water bottom ground 9 is not high, so It does not cause a large external force. Thereafter, the sampling cylinder 2 is withdrawn from the outer cylinder 3 by a diver and collected in the same manner as described above.

  The present invention can be applied not only to the water bottom ground 9 but also to land on the ground in the same manner as described above, regardless of whether it is solidified soil. At this time, the outer cylindrical body 2 softens by absorbing moisture in the ground, but when the amount of moisture in the ground is not sufficient, the outer cylindrical body 3 may be directly softened by supplying water.

DESCRIPTION OF SYMBOLS 1 Sampling tool 2 Sampling cylinder 3 Outer cylinder 4 Gap 5 Closure member 6 Grasping part 7 Fixing member 8 Ground core sample 9 Submarine ground

Claims (9)

  A sampling cylinder having at least a lower end opened, and an outer cylinder having an upper and lower end opened to be inserted into the ground together with the sampling cylinder inserted into the sampling cylinder, and the outer cylinder is softened by moisture A ground core sample collecting tool, characterized in that it is made of a material to be ground.   The ground core sample sampling tool according to claim 1, wherein a lubricant is interposed between an inner peripheral surface of the outer cylindrical body into which the sampling cylindrical body is inserted and an outer peripheral surface of the sampling cylindrical body.   2. A closing member for closing an annular gap between an outer peripheral surface of the sampling cylinder and an inner peripheral surface of the outer cylinder is provided at a lower end portion of the outer cylinder in which the sampling cylinder is inserted. Or the ground core sample collection tool of 2.   The ground core sample sampling tool according to any one of claims 1 to 3, wherein a grip portion protruding from the sampling cylinder is provided at an upper end portion of the sampling cylinder.   By inserting a sampling cylinder having at least a lower end into an outer cylinder formed of a material that has upper and lower ends opened and softened by moisture, and inserting the outer cylinder together with the sampling cylinder into the ground The ground is inserted into the sampling cylinder and filled, and after the outer cylinder is at least partially softened by moisture, the ground is filled with the ground filled with the sampling cylinder and extracted from the outer cylinder. To collect ground core samples.   The ground core sample collecting method according to claim 5, wherein a lubricant is interposed between an inner peripheral surface of the outer cylindrical body in which the sampling cylinder is inserted and an outer peripheral surface of the sampling cylinder.   After attaching a closing member for closing the annular gap between the outer peripheral surface of the sampling cylinder and the inner peripheral surface of the outer cylinder to the lower end of the outer cylinder in which the sampling cylinder is inserted, The ground core sample collecting method according to claim 5 or 6, wherein the outer tubular body is inserted into the ground together with the collecting tubular body.   The method for collecting a ground core sample according to any one of claims 5 to 7, wherein the ground is submerged ground.   The ground is formed of solidified soil, and before the solidified soil is solidified, the outer cylinder is inserted into the ground together with the sampling cylinder, and after the solidified soil is solidified, the sampling cylinder is The method for collecting a ground core sample according to any one of claims 5 to 8, wherein the ground core sample is extracted from the outer cylinder together with the filled solidified soil.

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