Soil sampling device

Abstract

To provide a soil sampling device which, by being able to be used by connecting to a ground survey machine, does not compromise simplicity of testing, with which no soil other than that at the desired depth gets mixed in, and by which soil at the desired depth can be reliably sampled.SOLUTION: A soil sampling device includes an inner tube 3 with a partially open tip, a rotating shaft part 4 that is connected to a rod and fitted to the inner tube so as to transmit rotation, fixed cap parts 5, 6 that are rotatable relatively to the rotating shaft part and have a stepped shape so as to restrict rotation to a certain angle, and an outer tube 2 with a partially open tip that can engage with the fixed cap after the aforesaid set is combined and inserted; when the rod is rotated in one direction, the non-open parts of the inner tube and outer tube form a continuous non-open surface inclined toward the shaft direction and maintain this state, thus preventing soil from entering or falling out, and when the rod is rotated in the opposite direction to the aforesaid rotation, the opening parts of the inner tube and outer tube overlap and maintain this state, making it possible to collect soil.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a device for collecting soil at a desired depth by being penetrated into the ground using a device used for ground investigation. Soil sampling device It relates thereto.

Background Art

[0002] Various ground investigations are carried out for the purpose of investigating the bearing capacity characteristics, settlement characteristics, stability against liquefaction, etc. of the ground on which buildings and structures are constructed. For example, the screw weight penetration test method (JIS A 1221:2020) is widely used as a method for investigating the bearing capacity characteristics of small-scale structures such as detached houses due to its simplicity. This method is a test method in which the screw point at the tip is rotationally penetrated into the ground while adding rods, and the static penetration resistance for evaluating the hardness, tightness, and soil layer composition of the ground is obtained. Such a method of penetrating a resistance body attached to a rod into the ground and investigating its properties is generally called a sounding test. Among the sounding tests, there are methods that involve collecting soil in the ground, but there are also methods that do not involve collecting soil, such as the above screw weight penetration test method. The soil quality of each soil layer constituting the ground is an important factor in considering the safety of the ground supporting buildings and the like. However, in a ground investigation method that does not involve collecting soil and does not have other functions for determining soil quality, there is a drawback that soil quality cannot be accurately determined. However, bringing in a separate device for collecting soil for determining soil quality impairs the simplicity of the test and is not economical. Therefore, it is conceivable to collect soil using a ground investigation device for sounding tests. Since a ground investigation device for sounding tests is equipped with a mechanism for penetrating the tip into the ground, a soil collection device that is connected to the ground investigation device and penetrated into the ground to collect soil is effective. This makes it possible to collect soil without significantly impairing simplicity, and it becomes possible to accurately determine soil with extremely high compressibility such as highly organic soil and soil with a high risk of liquefaction during an earthquake.

[0003] In addition, in order to correctly determine the soil quality at a specific depth, not only the soil needs to be sampled, but also the soil at the target depth must be sampled reliably without mixing in soil other than the soil at the target depth. To this end, some mechanism must be provided in the sampling device, and the mechanism must be operated with the sampling device inserted into the ground so that only the soil at a specific depth is sampled. As methods for this operation, methods such as operation by mechanical transmission means, operation by fluid pressure, and operation by electrical signals can be considered. However, in order to perform soil sampling more simply and economically, physical operation means that an operator on the ground can perform on the rod, that is, a mechanism that can be operated only by raising, lowering, and rotating the rod, is desirable. Such soil sampling devices have been proposed previously. For example, there are those proposed in Patent Documents 1 and 2.

[0004] In Patent Document 1, a soil sampling device is proposed that has sampling ports respectively provided in the axial directions of a double-cylindrical inner cylinder and outer cylinder that are relatively rotatable, and a sampling blade formed to protrude outward on one longitudinal side of the inner sampling port. This is inserted into an investigation hole resulting from a ground investigation, and by applying rotational forces in the forward and reverse directions via a rod, the sampling ports are opened and closed, and at the same time, it is possible to take in surrounding soil and sand with the sampling blade. There is an advantage that soil can be sampled simply by using the investigation hole.

[0005] In Patent Document 2, a sampling device is proposed that includes a core tube and a plug body that can slide up and down inside the tube. After being inserted into the bottom of the hole for sampling with the plug body closing the open lower end of the core tube, the plug body is raised to the upper limit position inside the core tube and connected, so that the soil at the bottom of the hole is pushed into the soil and sand receiving space formed inside the core tube from the open lower end of the core tube for sampling. This has the advantage that, since the tip in the penetration direction is open and pushed into the sampling depth, it is possible to sample soil that has not yet been disturbed by anything such as a screw point, other penetration tools, and the sampling device itself.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Patent Application Laid-Open No. 2004-332392 Patent Document 2 Japanese Patent Application Laid-Open No. 2014-156706 Summary of the Invention Problems to be Solved by the Invention

[0007] However, the above-described soil sampling device has problems. Regarding the device of Patent Document 1, since the soil scraped by the sampling blade is sampled from the sampling port provided in the axial direction using the investigation hole, when the side wall of the investigation hole is disturbed and soil from other depths adheres, or when soil from other depths adheres to the sampling device during insertion, there is a possibility that soil from depths other than the desired depth may be mixed in.

[0008] Regarding the device of Patent Document 2, after being inserted into the bottom of the hole with the lower end closed, the lower end is opened and the soil at the bottom of the hole is sampled from the tip in the penetration direction, so that the soil that has not yet been disturbed by anything such as the screw point, other penetration tools, and the sampling device itself is sampled, thereby eliminating the possibility of mixing of soil from depths other than the desired depth. However, since the lower end remains open even after the soil is sampled, especially when the sampling target layer is soft soil, there is a possibility that the sampled soil may fall from the open lower end before being pulled up to the ground, and there is a problem with the certainty of sampling.

[0009] The present invention has been made to solve the above problems, and it is possible to reliably and simply sample only the soil at a desired depth in the ground without mixing soil from other depths by using a device used for ground investigation. Soil sampling device It is an object of the present invention to provide such a device. Means for Solving the Problems

[0010] In order to solve the above problems, the invention according to claim 1 is a soil sampling device that is connected to a plurality of connectable rods by a ground investigation machine and penetrated into the ground, and is capable of sampling soil at a desired depth. A hollow outer tube with one end having an opening part and a non-opening part and through holes provided on the side surface A hollow inner tube with one end having an opening part and a non-opening part, inserted rotatably relative to the outer tube, and having a shape in which a rotary shaft component is fitted to the end on the opposite side of this direction A rotary shaft component having a shape that can be screwed to the rod and fitted to the inner tube, and capable of transmitting the rotation around the axis of the rod to the inner tube, and having a stepped shape formed around its axis A pair of fixed cap components mounted by being sandwiched around the axis so as to be relatively rotatable with respect to the rotary shaft component and fix the relative position in the axial direction, having screw holes provided on the side surfaces of each pair of components, and a fixed cap component having a stepped shape at one end of the pair of components With the inner tube fitted to the rotary shaft component and the fixed cap component attached, in a state where the assembly is inserted into the outer tube, the screw is fastened through the through hole of the outer tube to the screw hole provided in the fixed cap component, thereby engaging the sampling device as a whole When the stepped shape provided on the rotary shaft component and the stepped shape provided on the fixed cap component interfere with each other when reaching a certain angle in both directions of the relative rotation In a certain direction of relative rotation, at a certain angle of relative rotation, the opening part of the outer tube and the opening part of the inner tube overlap at least partially, and the relative rotation is restricted up to this angle In the relative rotation in the direction opposite to the above direction, at a certain angle of relative rotation, the non-opening part of the outer tube and the non-opening part of the inner tube form a continuous non-opening surface, and the relative rotation is restricted up to this angle The non-opening surface formed by the outer tube and the inner tube is a surface inclined with respect to the axial direction of a shape obtained by obliquely cutting a cylinder It is a soil sampling device.

[0011] When such a soil sampling device is connected to a rod and penetrates into the ground, the rotation of the outer pipe is resisted by the surrounding soil. Therefore, when rotation is applied to the rod, relative rotation occurs between the inner pipe and the outer pipe due to the rotation generated in the inner pipe accordingly. Depending on the direction of the relative rotation, the tip of the soil sampling device is in a non-opening state or a partially opened state. The non-opening state means that the intrusion of soil from the tip into the inner pipe and the outflow of soil from the tip inside the inner pipe are both suppressed. The partially opened state means that soil can be sampled from the opening part into the inner pipe from the tip. Furthermore, since the angle of the relative rotation is limited to this angle, even if the rod is rotated in the same direction further, the inner pipe and the outer pipe will rotate together, and the non-opening or opening state of the tip will be maintained.

[0012] Therefore, such a sampling device can prevent the mixing of soil at depths other than the desired depth by penetrating while applying rotation in the direction in which the tip closes when penetrating into the ground (hereinafter referred to as forward rotation). By applying rotation in the direction in which the tip opens at the desired depth (hereinafter referred to as reverse rotation), soil can be sampled from the opened surface. By applying forward rotation after soil sampling to close the tip, it is possible to prevent the sampled soil from falling. Therefore, it is possible to reliably sample only the soil at the desired depth.

[0013] The configuration in which the non-opening surface is a surface inclined with respect to the axial direction and the opening parts overlap due to the relative rotation between the outer pipe and the inner pipe can be implemented, for example, by making the tip of the outer pipe have a shape with an oblique cut and providing a semi-circular opening in the tip-side projection plane. The tip of the inner pipe is shaped such that when engaged with the outer pipe at a certain rotation angle, it closes the opening of the outer pipe to form a continuous non-opening surface, and the other parts of the tip are opened.

Advantages of the Invention

[0014] As described above, for the soil sampling device according to claim 1, when penetrating into the ground, by penetrating with forward rotation, it is possible to prevent the soil at other depths from being mixed in. After reaching the target depth, by applying reverse rotation to the rod, the tip opens, and by performing penetration in the open state, it is possible to collect the soil at the target depth. Further, after collecting the soil, by applying forward rotation to the rod to close the tip of the soil sampling device, it is possible to pull it up to the ground without dropping the collected soil and obtain it. Also, by providing an inclined surface inclined with respect to the axial direction in a shape with an oblique cut at the tip, When driving in the ground while rotating, the tip of the inclined surface of the outer pipe scrapes the soil, and by driving while letting the scraped soil escape onto the inclined surface, the driving performance is improved compared to simply cutting perpendicularly in the axial direction. Also, by reducing the force applied to the closed surface of the inner pipe, wear and deformation occurring in the inner pipe can be suppressed, and the service life can be extended. Furthermore, with the corresponding component configuration, it can be easily disassembled and assembled by screw operation. Therefore, after soil sampling, it is convenient to clean and reassemble the components and use them again.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

Examples

[0016] Hereinafter, The first embodiment corresponding to claim 1 The soil sampling device will be described with reference to FIGS. 1 to 4. FIG. 1 is a front view seen from the opening surface side of the soil sampling device. 1a is an opening, and the entry and exit of soil from this part are controlled by closing or opening it by forward or reverse rotation. 1b is a connection part with a rod, and this part is screwed and connected to the rod, and is penetrated into the ground using a ground investigation machine equipped with a mechanism capable of rotationally driving and lifting and lowering the rod. FIG. 2 is a side view of the soil sampling device. FIG. 3 is an assembly drawing of each component. The sampling device is composed of an outer tube 2, an inner tube 3, a rotating shaft component 4, and fixed cap components 5 and 6. The inner tube 3 is inserted into the outer tube 2 so as to be relatively rotatable. The outer tube opening 2a and the inner tube opening 3a are in an open state at an overlapping angle, enabling soil sampling, and the outer tube opening 2a is in a closed state at an angle overlapping a non-opening part other than the opening of the inner tube, preventing the intrusion and dropping of soil. The rotating shaft component 4 is inserted into the outer tube in a state where the fitting part 4b of the rotating shaft component with the inner tube and the fitting part 3b of the inner tube with the rotating shaft component are fitted. The other end of the rotating shaft component corresponds to the connection part 1b with the rod in FIG. 1, and the rotational movement of the rod is transmitted to the inner tube via the rotating shaft component. The fixed cap component (1) 5 and the fixed cap component (2) 6 are fitted so as to sandwich the rotating shaft component and then inserted into the outer tube. The fixed cap component and the rotating shaft component are relatively rotatable, but when the relative rotation reaches a certain angle, the stepped shape part 4a for rotational angle control and the stepped shape part 5b for rotational angle control interfere with each other, so that the relative rotation in each rotational direction is limited to 180 degrees. By this mechanism, when a forward rotation is applied to the rod, the soil sampling device closes and the closed state is maintained, and when a reverse rotation is applied to the rod, the soil sampling device opens and the open state is maintained, so that the opening and closing state of the soil sampling device can be operated using the rotational drive mechanism of the ground investigation machine from the ground. The through hole 2b of the outer tube is a hole provided for passing a screw, and by passing the screw through this hole and fastening it to the screw holes 5a and 6a of the fixed cap component, each fixed cap component is engaged with the outer tube, and the inner tube and the rotating shaft component inserted into the outer tube are also indirectly engaged with the outer tube through this engagement, and the soil sampling device is assembled.Figure 4 is an assembly diagram showing that the inner tube 3, the rotary shaft component 4, and the fixed cap components 5 and 6 are inserted after being combined with the outer tube 2, and the fastening screw 7 between the outer tube and the fixed cap is fastened to the screw hole of each fixed cap component through the through hole of the outer tube to be engaged as a set of soil sampling devices.

[0017] The soil sampling method using the soil sampling device of the first embodiment This will be described with reference to FIG. 5. The soil sampling of this embodiment is performed by sequentially executing the following steps (A) to (F). (A) Connect the soil sampling device to the rod and lower it while applying forward rotation to the rod. (B) Stop lowering when the tip of the soil sampling device reaches the upper end of the sampling target layer. (C) Apply reverse rotation to the rod to open the tip of the soil sampling device. (D) By lowering the soil sampling device with its tip open, the soil of the sampling target layer is sampled into the inner tube of the soil sampling device. (E) When reaching the lower end of the sampling target layer, apply forward rotation to the rod to close the tip of the sampling device. (F) Raise the rod with the tip of the sampling device closed and pull the sampling device to the ground. According to this soil sampling method, since the tip is in a closed state during penetration, it is possible to prevent the intrusion of soil at other depths and perform high-precision soil quality determination. Also, by closing the tip again after soil sampling and pulling it up, it is possible to reliably sample the soil without dropping the sampled soil.

Explanation of Signs

[0018] 1 Soil sampling device 1a Opening 1b Connection part with rod 2 Outer tube 2a Outer tube opening 2b Through hole 3 Inner tube 3a Inner tube opening 3b Fitting part with rotary shaft component 4 Rotary shaft component 4a Step-shaped part for rotation angle control 4b Fitting part with inner tube 5 Fixed cap part (1) 5a Thread hole 5b Step-shaped part for controlling the rotation angle 6 Fixed cap part (2) 6a Thread hole 7 Fastening screw between the outer tube and the fixed cap

Claims

1. A soil sampling device that is connected to a plurality of connectable rods by a ground investigation machine and penetrates into the ground to collect soil at a desired depth, comprising: a connecting portion connectable to the rod; a hollow outer tube with one-way tips consisting of an open portion and a non-open portion; a hollow inner tube with one-way tips consisting of an open portion and a non-open portion, inserted rotatably relative to the outer tube, and configured to rotate with the rotation around the axis of the rod; means for engaging the outer tube and the inner tube; locking means for restricting the relative rotation to a certain angle for both directions of rotation; when the relative rotation is in one direction, at a certain angle of relative rotation, a non-open surface is formed by the non-open portions of the outer tube and the inner tube being continuous, and the relative rotation is restricted up to that angle; when the relative rotation is in the direction opposite to the above, at a certain angle of relative rotation, the open portions of the outer tube and the inner tube overlap at least partially, and the relative rotation is restricted up to that angle. A soil sampling device characterized by this.

2. The soil sampling device according to Claim 1, wherein the non-open surface formed by the outer tube and the inner tube is a surface inclined with respect to the axial direction of a shape obtained by obliquely cutting a cylinder.

3. In the soil sampling device according to Claim 1 or 2, the engaging means between the outer tube and the inner tube and the locking means for restricting the relative rotation to a certain angle are: a rotary shaft component that is fitted to the inner tube so as to be able to transmit rotation, has a stepped shape formed around the axis, and a connecting portion that can be screwed with the rod; a pair of fixed cap components that are rotatable relative to the rotary shaft component and are attached by being sandwiched around the axis so as to fix the relative position in the axial direction, screw holes are provided on the side surfaces of each pair of components, and one end of the pair of components has a fixed cap component with a stepped shape; an outer tube provided with a through hole on the side surface; an inner tube provided with a shape in which a rotary shaft is fitted to the inner tube; The engaging means is by inserting a set in which the inner tube is fitted to the rotary shaft component and the fixed cap component is attached into the outer tube, and fastening a screw through the through hole of the outer tube to the screw hole provided in the fixed cap component. The locking means is that the stepped shape provided on the rotary shaft component and the stepped shape provided on the fixed cap component interfere with each other when a certain angle of relative rotation in both directions of their relative rotation is reached, thereby restricting the relative rotation beyond that angle. A soil sampling device.

4. A ground investigation machine equipped with a mechanism capable of rotationally driving and vertically driving the rod, and a soil sampling device according to any one of claims 1 to 3, is a soil sampling method for sampling soil at a desired depth underground, comprising: After connecting the soil sampling device to the tip of the rod, By applying rotation transmitted via the rod to the inner pipe, while lowering the rod while applying rotation in the direction in which relative rotation occurs between the outer pipe that receives the resistance of the soil in the ground and the inner pipe, which is rotation in the direction in which the non-opening surface is formed (hereinafter referred to as forward rotation), so that the tip of the sampling device penetrates to a predetermined depth while maintaining a closed state; By applying rotation transmitted via the rod to the inner pipe, rotation in the direction in which relative rotation occurs between the outer pipe that receives the resistance of the soil in the ground and the inner pipe, which is rotation in the direction in which the opening surfaces of the outer pipe and the inner pipe overlap (hereinafter referred to as reverse rotation), so as to form a state in which at least a part of the tip of the sampling device is open; By lowering a predetermined descending length rod, a step of sampling soil into the inner pipe from the opening; A step of closing the tip of the sampling device by applying forward rotation to the rod; A step of pulling up the sampling device to the ground by raising the rod and taking out the soil sampled underground from the sampling device. A soil sampling method comprising these steps.

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