Unconsolidated soil sampling device

Abstract

To enable sampling even in a borehole of a small diameter, by reducing an outer diameter of a guide pipe as a whole.SOLUTION: At a tip part of a guide pipe 3 inserted into a borehole, a first short pipe 4a is connected by a joint part 6a which rotates in a flat surface crossing obliquely with an angle of about 22.5 with respect to the central axis of the guide pipe 3, and also, at the tip part of the first short pipe 4a, a second short pipe 4b is connected via a joint part 6b which moves in the flat surface inclined toward the opposite side from the joint part 6a. At the position opposing to each other in the diameter direction of the guide pipe 3, a connection part 8a for bending and a connection part for returning 8b are provided, on an outer peripheral part of the first short pipe 4a, connection parts 9a, 9b are provided, and at the position opposing to each other in the diameter direction of the second short pipe 4b, a connection part 10a for bending and a connection part 10b for returning are provided. By pulling wires 7a, 7b passing through these connection parts, each of the short pipes 4a, 4b is rotated, is bent with respect to the guide pipe 3, and is returned again.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus for collecting a portion of soil into which a chemical solution for ground improvement has been injected as a sample while the soil is still unconsolidated, such as immediately after the injection of the chemical solution. [Background technology]

[0002] It is widely practiced to improve the ground by injecting a chemical solution into the soil and solidifying it. The chemical solution is injected directly into a relatively deep area of ​​the target area, so first, a borehole is drilled, a pipe such as a hose is inserted into the borehole (sometimes called erection), and the chemical solution is injected into the soil from the pipe. In this case, since it is necessary to expand the area where the chemical solution is injected horizontally (in a direction perpendicular to the borehole), a horizontal borehole is drilled extending horizontally from a vertical main borehole. An example of the boring and chemical solution injection method is described in Patent Document 1. In the method described in Patent Document 1, a guide box having a curved hole penetrating in an arc shape from the top surface to the side is inserted at a position of a predetermined depth in the main borehole, and a flexible boring member is inserted from the upper side of the guide box, and the boring member is bent horizontally along the curved hole of the guide box, and the boring member is advanced horizontally in this way to form a horizontal borehole. This operation is performed at multiple locations at different depths to drill multiple horizontal boreholes. After the boring tool is removed from the guide box and the borehole, a hose for injecting chemicals is inserted into the horizontal borehole via the guide box, and the chemicals are injected into the soil by flowing out from the hose.

[0003] The soil into which the chemical solution has been injected is inspected to see if it has been improved as intended. In this case, since it would take a long time to wait for the soil into which the chemical solution has been injected to solidify, samples are taken from unconsolidated soil, and the samples are consolidated before being inspected. The applicant has already proposed a technique for collecting such samples in Patent Document 2. In the device or method described in Patent Document 2, a guide block having a guide section curved at about 90 degrees inside, similar to the guide box described in Patent Document 1, is attached to the tip of a guide tube and inserted into a borehole. When a flexible sampling tube consisting of an inner and outer tube is inserted into the guide tube, the sampling tube is turned sideways by the guide block and pushed into the soil in a muddy or fluid state into which the chemical solution has been injected. In this state, the inner tube and the outer tube are shifted relatively in the longitudinal direction to open the sampling port, and the tributary is taken into the sample storage section provided in the inner tube. The sampling tube is then pulled up to collect the sample. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-59342 A [Patent Document 2] JP 2020-186598 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the devices described in Patent Document 1 and Patent Document 2, a guide box or guide block is used to move the boring member or sampling pipe sideways (or horizontally). The guide members for changing direction are configured so that an opening and a pipe line facing up and down, and a pipe line and an opening line that bend smoothly from the pipe line and face sideways are provided inside a so-called housing. Therefore, the guide member has a shape in which the tip side of the guide member that is bent sideways protrudes horizontally, so the outer diameter or width of the guide member as a whole becomes large. In contrast, the main borehole is for sending the boring member or sampling pipe to a deep position in the ground, and even if it needs to be deep, it does not need to be thick, and it is preferable that it is thin in terms of ease of drilling. In other words, the conventional guide members are contrary to the requirements for the main borehole, and there were areas that needed to be improved in terms of reducing the construction period and costs.

[0006] The present invention aims to provide an apparatus capable of efficiently and quickly collecting soil samples into which a chemical solution has been injected, and capable of collecting samples even from narrow boreholes. [Means for solving the problem]

[0007] The present invention relates to an unconsolidated soil sampling device that has a guide pipe that is inserted into a borehole excavated for ground improvement, and a flexible sampling pipe that is inserted into the guide pipe from its upper part and is pushed from the lower end of the guide pipe into soil that has been softened by the injection of a chemical solution, and that samples the unconsolidated soil through the sampling pipe, and a plurality of short pipes are connected to the tip of the guide pipe via a rotary joint unit in a line up in the longitudinal direction of the guide pipe, and the rotary joint unit is configured to rotate within a plane that is inclined at a predetermined inclination angle that is not perpendicular to the central axis of the guide pipe or the short pipe, and a bending connector and a return connector are provided at different positions in the circumferential direction on the outer periphery of the guide pipe, and a driven connector that is connected to at least one of the bending connector and the return connector is provided on the outer periphery of the plurality of short pipes. a bending line connecting the bending connection portion to any of the driven connection portions on the short tube, and a return line connecting the return connection portion to any of the driven connection portions on the short tube including the other driven connection portions, the return line being configured to pull the driven connection portions connected by the bending line toward the bending connection portion on the guide tube by the bending line, thereby rotating the rotary joint portion to bend each of the short tubes relative to the guide tube, and to pull the driven connection portions connected by the return line toward the return connection portion on the guide tube by the return line, thereby rotating the rotary joint portion to return each of the short tubes from a bent state relative to the guide tube to a straight state.

[0008] In the present invention, the short pipe includes a first short pipe connected to the guide pipe by a first rotary joint portion, and a second short pipe connected to the first short pipe by a second rotary joint portion, the first rotary joint portion is configured to rotate the guide pipe and the first short pipe relatively within a plane inclined at a first predetermined angle less than 45 degrees with respect to the central axis of the guide pipe, and the second rotary joint portion is configured to rotate the first short pipe and the second short pipe relatively within a plane inclined at an angle obtained by subtracting the first predetermined angle from 45 degrees with respect to the central axis of the first short pipe. the bending connecting portion and the return connecting portion are provided at positions rotated 180 degrees relative to each other in the circumferential direction of the guide tube, the driven connecting portion having the bending filament and the return filament passed therethrough is provided on the outer periphery of the first short tube, and the driven connecting portion may be provided on the outer periphery of the first short tube with a bending driven connecting portion to which the bending filament is fixed and a return driven connecting portion to which the return filament is fixed, the driven connecting portions being spaced 180 degrees apart from each other in the circumferential direction of the first short tube.

[0009] In the present invention, a cylinder that expands and contracts a rod is attached to the outer periphery of the guide tube in parallel to the guide tube, and the bending line and the return line are connected to the rod, and the rod expands and contracts to pull one of the bending line and the return line and relax the other, thereby bending the short tube relative to the guide tube, or returning the short tube that is bent relative to the guide tube to an orientation that is in a straight line relative to the guide tube. Effect of the Invention

[0010] According to the present invention, by pulling the bending umbilical cord, a force acts on the short pipe in a direction that brings the bending connector and the driven connector, which are connected to the bending umbilical cord, closer to each other. Since the short pipe is connected by a rotary joint that rotates in a plane inclined at a predetermined angle, the pulling force of the bending umbilical cord acts as a torque and rotates relative to the guide pipe. Since the rotation occurs at the rotary joint, the short pipe swings relative to the guide pipe, and as a result, the short pipe bends relative to the guide pipe. Conversely, if the return umbilical cord is pulled, the short pipe returns to a direction in which it is aligned in a straight line relative to the guide pipe, and the entire pipe becomes a so-called straight pipe. Therefore, the portion of the guide pipe that protrudes outward in the radial direction is a small portion of each connector, and the entire pipe from the guide pipe to the short pipe can be configured to have a small diameter. Therefore, the inner diameter of the borehole into which the sample is inserted can be reduced, and the resistance when the guide pipe is inserted toward the soft soil accumulated in the borehole is reduced, making it easier to insert the guide pipe into the borehole. In addition, since the length of the short tube is not particularly restricted, the portion extending horizontally from the guide tube can be made long without increasing the inside diameter of the borehole. Therefore, the length of the portion guiding the sampling tube in the horizontal direction can be made sufficient, and the sampling tube can be reliably curved and guided in the horizontal direction.

[0011] In particular, if a configuration is adopted in which a cylinder is provided parallel to the outer periphery of the guide tube as an actuator that pulls and relaxes the filament for bending and returning, the entire tube from the guide tube to the short tube can be configured with a small diameter. [Brief description of the drawings]

[0012] [Figure 1] 1 is a front view showing a schematic diagram of an overall configuration of an embodiment of the present invention; [Diagram 2] FIG. 2 is a front view showing a lower end portion of the guide pipe. [Diagram 3] 13 is a perspective view showing a restored state in which the short tubes extend in a straight line aligned with the guide tube. FIG. [Figure 4]11 is a perspective view showing a bent state in which each short tube is rotated and bent relative to the guide tube. FIG. [Diagram 5] FIG. 1 is a perspective view showing a schematic example of an insertion device. [Figure 6] 4 is a mechanical diagram for explaining the configuration of a rotation clamp mechanism. FIG. [Figure 7] FIG. 1 is a circuit diagram showing an example of an air circuit including a switching valve for operating a cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is merely one example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0014] The device according to the present invention is a device for collecting samples from soil into which a chemical solution has been injected for ground improvement, and the injection of the chemical solution is carried out by a conventionally known method. In an unconsolidated state immediately after the injection of the chemical solution, the soil is in a soft state with a certain degree of fluidity, and a part of the soil is collected to verify the state of injection of the chemical solution and its strength when consolidated. The sample is collected by extending a sampling pipe horizontally from a borehole excavated for the injection of the chemical solution, and collecting an appropriate amount of soil from an appropriate point within a range of a predetermined radius centered on the borehole. Figure 1 is a schematic diagram for explaining the collection situation, in which the upper opening of the borehole 1 is closed by a steel plate 2 that serves as a workbench, and a guide pipe 3 is inserted into the borehole 1 through the steel plate 2 and suspended from the steel plate 2. The guide pipe 3 needs to be lowered to a depth of several meters to a dozen meters, so it is composed of multiple pipes connected together with a length that is easy to handle. A flange is attached to the upper end of this guide pipe 3, and the flange is hooked onto the iron plate 2 so that the guide pipe 3 is suspended from the iron plate 2.

[0015] The tip (lower end) of the guide pipe 3 is bendable by a number of short pipes. The bent structure is shown in FIG. 2. These short pipes are configured to change direction between a state in which they extend linearly (straight pipe shape) relative to the guide pipe 3 and a state in which they are curved at a substantially right angle (bent state) relative to the guide pipe 3. As shown in FIG. 2, a base pipe section 5 having the same diameter as the guide pipe 3 is connected to the lower end of the guide pipe 3. This base pipe section 5 is substantially a part of the guide pipe 3. A number of short pipes 4a, 4b (two in the example of FIG. 2) are connected to the tip side of the base pipe section 5. These short pipes 4a, 4b may be pipes having the same diameter as the base pipe section 5, and the total length of the short pipes 4a, 4b may be longer than the radius of the borehole 1.

[0016] The first short pipe 4a is rotatably connected to the base pipe 5 by the rotary joint 6a. The rotary joint 6a is configured such that, for example, a flange provided at the tip of the base pipe 5 is wrapped and held by a holding part with a U-shaped cross section provided at the upper end of the first short pipe 4a so as to be rotatable relative to the first short pipe 4a. The flange and the holding part are provided along a plane inclined at a first predetermined angle (about 22.5 degrees in the example shown in FIG. 2) with respect to the central axis of the guide pipe 3 (or the base pipe 5). That is, the rotary joint 6a is configured so that the base pipe 5 and the first short pipe 4a rotate relative to each other within a plane inclined at an angle of about 22.5 degrees with respect to each other. Therefore, when the first short pipe 4a rotates 180 degrees from the state shown in FIG. 2 in which the central axes of the guide pipe 3 and the first short pipe 4a are aligned on the same axis, the first short pipe 4a is bent at an angle of about 45 degrees with respect to the guide pipe 3 or the base pipe 5.

[0017] The second short pipe 4b is rotatably connected to the tip (lower end) of the first short pipe 4a by a rotary joint 6b having the same configuration as the above-mentioned rotary joint 6a. This so-called second rotary joint 6b has an inclination angle opposite to that of the above-mentioned so-called first rotary joint 6a. As shown in FIG. 2, when the guide pipe 3 and each short pipe 4a, 4b are in a straight line (straight pipe state), the first rotary joint 6a is inclined upward to the right in FIG. 2, whereas the second rotary joint 6b is inclined upward to the left. The angle is about 22.5 degrees. In other words, this angle is the angle obtained by subtracting the inclination angle of the first rotary joint 6a from 45 degrees. Therefore, when the second short pipe 4b rotates 180 degrees relative to the first short pipe 4a from the state shown in FIG. 2, the second short pipe 4b is bent at an angle of 45 degrees relative to the first short pipe 4a. As described above, since the first short pipe 4a is bent at an angle of 45 degrees relative to the guide pipe 3 or the base pipe section 5, the second short pipe 4b can be bent at an angle of 90 degrees overall relative to the guide pipe 3 or the base pipe section 5. This allows the open end of the second short pipe 4b, which corresponds to the tip opening of the guide pipe 3 as a whole, to face horizontally inside the borehole 1.

[0018] The mechanism for rotating each of the short tubes 4a, 4b is configured to rotate each of the short tubes 4a, 4b by pulling each of the short tubes 4a, 4b in the circumferential direction with a filament such as a wire. In the example shown in Fig. 2, connecting parts 8a, 8b are provided at positions 180 degrees out of phase with each other in the circumferential direction (positions rotated 180 degrees relative to each other) on the outer periphery of the lower end of the guide tube 3. These connecting parts 8a, 8b are protrusions provided with a through hole through which a wire can pass, and one connecting part 8a serves as the bending connecting part in the present invention, and the other connecting part 8b serves as the return connecting part in the present invention.

[0019] Also, the first short tube 4a is provided with connecting parts 9a, 9b on its outer periphery. These connecting parts 9a, 9b on the first short tube 4a correspond to the driven connecting parts in the present invention, and are protrusions with through holes through which a wire can pass, similar to the connecting parts 8a, 8b on the guide tube 3. These connecting parts 9a, 9b may be either one of them functionally, but in the example shown in FIG. 2, they are provided at the upper end of the first short tube 4a and at the middle part in the axial direction (longitudinal direction), at the same position in the circumferential direction, that is, on a straight line along the longitudinal direction of the first short tube 4a. Moreover, these connecting parts 9a, 9b are provided at a position aligned on the same axis as the above-mentioned return connecting part 8b when the first short tube 4a is aligned on a straight line with the guide tube 3 (i.e., in the return state). In other words, the relative positions of the return connecting part 8b and the connecting parts 9a, 9b on the first short tube 4a are determined so that the distance between them is the shortest in the return state.

[0020] Furthermore, a pair of connecting parts 10a, 10b are provided at the upper end of the second short tube 4b (for example, a holding part constituting the rotary joint part 6b). These connecting parts 10a, 10b correspond to the driven connecting parts in the present invention, and in the example shown in Fig. 2, they are so-called terminal connecting parts to which the wire is tied and fixed. More specifically, these terminal connecting parts 10a, 10b are protrusions provided at positions 180 degrees apart in the circumferential direction, with one connecting part 10a serving as the bending driven connecting part and the other connecting part 10b serving as the return driven connecting part. That is, in the return state where each of the short tubes 4a, 4b is aligned in a straight line with the guide tube 3, the bending connecting part 10a is located directly below (on the same straight line) as the bending connecting part 8a of the guide tube 3, and therefore the other returning connecting part 10b is located directly below (on the same straight line) as the returning connecting part 8b of the guide tube 3 and the connecting parts 9a, 9b of the first short tube 4a in the return state where each of the short tubes 4a, 4b is aligned in a straight line with the guide tube 3. The relative positions of these connecting parts 8a, 8b, 9a, 9b, 10a, 10b in the return state are shown in Figure 3.

[0021] The wires provided are a bending wire 7a and a return wire 7b. The bending wire 7a corresponds to the bending wire of the present invention, and is for rotating the short tubes 4a, 4b so as to bend the short tubes 4a, 4b relative to the guide tube 3 (or the base tube portion 5). The bending wire 7a passes through the bending joint 8a in the guide tube 3 and the joints 9a, 9b in the first short tube 4a, and is fixed to the bending joint 10a in the second short tube 4b. On the other hand, the return wire 7b corresponds to the return wire of the present invention, and is for rotating the short tubes 4a, 4b so as to return them to the return state described above. The bending wire 7a passes through the return joint 8b in the guide tube 3 and the joints 9a, 9b in the first short tube 4a, and is fixed to the return joint 10b in the second short tube 4b. Therefore, each of the connecting portions 9a, 9b of the first short tube 4a serves both as a connecting portion for bending and a connecting portion for returning.

[0022] Cylinders 11 are provided as actuators for bending each of the short pipes 4a, 4b relative to the guide pipe 3 or the base pipe 5 and for returning the short pipes 4a, 4b from the bent state to their original straight pipe state. In the example shown in FIG. 2, a double-acting air cylinder for extending and retracting a rod 11a is used, and the rod 11a is attached to the outer periphery of the guide pipe 3 in the longitudinal direction of the guide pipe 3 (in a direction parallel to the central axis) with the rod 11a facing upward. Note that piping to the cylinder 11 is omitted in FIG. 2. A pulley 12 attached to the guide pipe 3 is provided above the cylinder 11, and the aforementioned return wire 7b is wound around the pulley 12 and turned downward, and is connected to the rod 11a in this state. In contrast, the bending wire 7a is directly connected to the rod 11a. That is, the cylinder 11 extends its rod 11a upward to pull the bending wire 7a and relax the return wire 7b, thereby bending each of the short tubes 4a, 4b relative to the guide tube 3, and conversely, contracts (pulls down) the rod 11a to relax the bending wire 7a and pull the return wire 7b, thereby returning each of the short tubes 4a, 4b to a state where they are aligned in a straight line relative to the guide tube 3. FIG. 4 shows the state where each of the short tubes 4a, 4b is bent at approximately 90 degrees relative to the guide tube 3. In order to prevent excessive loosening of the wires 7a, 7b and the associated entanglement, it is preferable to interpose a tension spring such as a coil spring in the middle of each of the wires 7a, 7b. In addition, it is preferable to cover the entire cylinder 11, wire 7, pulley 12, etc. with an appropriate cover sheet (or boot) to protect them from contamination by the soil S.

[0023] The sampling pipe 13 for sampling samples is inserted into the guide pipe 3 suspended inside the borehole 1, and is fed into the soil S from each of the short pipes 4a, 4b bent horizontally at the tip of the guide pipe 3, and samples are sampled through the sampling pipe 13. Since the sampling pipe 13 needs to be bent horizontally from the guide pipe 3, at least the tip side (lower end side) is made of a flexible pipe or tube such as a corrugated pipe. On the other hand, the rear end side (upper end side) of the sampling pipe 13 may be a rigid synthetic resin pipe such as polyvinyl chloride, and in this case, it is preferable to configure the multiple pipes to be connected by a screw joint or the like to make it easier to handle. Also, a transparent pipe may be used in part so that the sampling situation can be visually observed.

[0024] The sample can be collected by either the so-called negative pressure extraction method, in which the soil S that has entered the inside of the sampling tube 13 is pulled up together with the sampling tube 13, or the so-called vacuum suction method, in which the soil S is sucked through the sampling tube 13. In the negative pressure extraction method, the sampling tube 13 with its rear end sealed is inserted into the guide tube 3 from its end on the ground side, and is inserted into the soil S from the tip of the short tubes 4a, 4b that are bent horizontally. Since the sampling tube 13 is bent horizontally at the point from the base tube 5 to the short tubes 4a, 4b, it is preferable to insert the sampling tube 13 while rotating it in order to reduce catching and resistance at that time. Since the tip of the sampling tube 13 is open, the soil S tries to enter into it during the process of pushing the sampling tube 13, but since the rear end of the sampling tube 13 is sealed and air is filled inside, the soil S does not enter the entire part that has been sent into the soil S. When the tip of the sampling tube 13 reaches the target location at a predetermined depth, the sealing of the rear end of the sampling tube 13 is released to the atmosphere. In this state, when the sampling tube 13 is shaken by pushing and pulling it back and forth or rotating it left and right, the soil S penetrates into the inside of the sampling tube 13 because the soil S is unconsolidated and has fluidity and is under a certain amount of pressure. In this state, the rear end of the sampling tube 13 is sealed again in an airtight state, and the sampling tube 13 is then raised to the ground. The soil S inside the sampling tube 13, i.e., the sample, tries to flow out of the sampling tube 13, but since the sampling tube 13 is sealed, the sample is held inside the sampling tube 13 by the negative pressure generated inside. After the sampling tube 13 is raised to the ground in this way, the sealing of the rear end is released to allow the sample inside to flow out into a specified container.

[0025] On the other hand, in the vacuum suction method, the sampling tube 13 is inserted to a desired depth and connected to a specified container with a sealed structure, and negative pressure is generated by sucking air from inside the container with a vacuum pump. In this way, the unconsolidated soil S, i.e., the sample, is sucked into the sampling tube 13 and taken into the container via the sampling tube 13.

[0026] The insertion and removal of the sampling tube 13 can also be performed by mechanical force, and an example of a device for this purpose is shown diagrammatically in FIG. 5. This insertion device 14 is portable, and a guide post 17 is erected on a frame 16 equipped with casters 15. A rotating clamp mechanism 18 is attached to this guide post 17 so that it can move up and down. As diagrammatically shown in FIG. 6, the rotating clamp mechanism 18 has a pair of drive rollers 18a and a pair of guide rollers 18b that clamp the sampling tube 13 between the drive rollers 18a, and the guide rollers 18b are attached to an opening / closing lever 18c so that they can move between a position close to the drive roller 18a and a position far away from the drive roller 18a. This opening / closing lever 18c is configured to maintain the state in which the sampling tube 13 is clamped between the drive roller 18a and the guide roller 18b by providing a mechanism with a locking function such as a toggle mechanism in the hinge portion. The drive roller 18a is connected to a motor 18d by a chain or belt and rotated by the motor 18d. An actuator (not shown) is provided to move the rotary clamp mechanism 18 up and down. This actuator may be an air cylinder disposed along the guide post 17.

[0027] An air compressor 19 and a vacuum pump 20 can be mounted on both sides of the guide column 17. The air compressor 19 is a pressure source for the cylinder 11 that bends and returns the short pipes 4a and 4b and for the air cylinder that raises and lowers the rotary clamp mechanism 18, and is adapted to supply and discharge compressed air to the cylinder 11 and the air cylinder by an appropriate switching valve (not shown). FIG. 7 shows an air circuit for driving the cylinder 11, and a manual switching valve 21 is provided between the air compressor 19 and the cylinder 11. The switching valve 21 has an input port 21a, a first output port 21b, a second output port 21c, and an open port 21d, and is configured to be manually switched between a state in which the input port 21a is connected to one of the output ports 21b (21c) and the other output port 21c (21b) is connected to the open port 21d, and a state in which these communication states are reversed.

[0028] In Fig. 1, reference numeral 22 denotes a sampling box, which is a transparent, sealable box made of synthetic resin or the like, and is configured to connect a sampling tube 13 inserted into the soil S, and also to connect a vacuum pump 20. That is, when the vacuum pump 20 sucks from the sampling box 22 to generate negative pressure, the sampling tube 13 sucks in unconsolidated, fluid soil S, which flows out into the sampling box 22. This state can be visually observed because the sampling box 22 is transparent, and the required amount can be sampled.

[0029] Next, the operation of the sampling device according to the present invention will be explained together with the procedure for sampling samples. After the injection of the chemical solution is completed, a steel plate 2 is placed at the open end of the borehole 1, and a guide pipe 3 is inserted into the borehole 1 through a through hole provided in the steel plate 2. In this case, the guide pipe 3 to which the above-mentioned short pipes 4a and 4b are attached is set as the lowest end, and other guide pipes 3 are successively added to it to lower the guide pipe 3 to a predetermined depth. After that, the flange attached to the guide pipe 3 is hooked onto the steel plate 2, and the guide pipe 3 is held in a state of being suspended from the steel plate 2.

[0030] When the guide tube 3 is lowered in this manner, the rod 11a of the cylinder 11 attached to its outer periphery is contracted. In other words, the return wire 7b connected to the short tubes 4a and 4b is pulled. The return wire 7b is inserted into the return connector 8b of the guide tube 3 and the two connectors 9a and 9b of the first short tube 4a, and its tip is fixed to the return connector 10b of the second short tube 4b. Therefore, when the return wire 7b is pulled, a circumferential force acts on the connectors 8b, 9a, 9b, and 10b to which it is connected, so that they are aligned in a straight line. As described above, the relative positions of these connecting parts 8b, 9a, 9b, 10b are aligned in a straight line with each short pipe 4a, 4b extending in a straight line on the extension line of the guide pipe 3, so that by pulling the return wire 7b, the guide pipe 3 and the short pipes 4a, 4b at the tip end thereof become one straight pipe. Therefore, even if the borehole 1 is a vertical hole with a small inner diameter, the guide pipe 3 can be easily inserted into the borehole 1 without any trouble. In other words, the total length of the short pipes 4a, 4b that are bent or curved at an almost right angle to the guide pipe 3 is not restricted by the inner diameter of the borehole 1, and can be made sufficiently long as necessary.

[0031] After the guide tube 3 is suspended and set as described above, the switching valve 21 is switched to send air to the cylinder 11, and the rod 11a is extended. As a result, the bending wire 7a is pulled and the return wire 7b is loosened. The action of pulling the bending wire 7a is the same as the action of pulling the return wire 7b described above, and it is an action of pulling each of the short tubes 4a and 4b in the circumferential direction so that the connecting parts 8a, 9a, 9b, and 10a through which the bending wire 7a penetrates or is fixed are aligned on a line parallel to the central axis of the guide tube 3 and each of the short tubes 4a and 4b and approach each other as close as possible. In other words, the first short tube 4a is rotated so that the connecting parts 9a and 9b provided on its outer periphery are aligned directly below the bending connecting part 8a provided on the guide tube 3. The rotary joint portion 6a connecting the guide tube 3 and the first short tube 4a is configured to rotate within a plane inclined at approximately 22.5 degrees with respect to the central axis of the guide tube 3 and the first short tube 4a, so that the first short tube 4a rotates 180 degrees from the return state described above, and becomes bent at an angle of 45 degrees with respect to the guide tube 3.

[0032] The second short pipe 4b is pulled in the circumferential direction and rotates so that the bending joint 10a provided on its outer periphery is aligned directly below the joints 9a, 9b of the first short pipe 4a. The rotary joint 6b connecting the first short pipe 4a and the second short pipe 4b is configured to rotate in a plane inclined at about 22.5 degrees with respect to the central axis of each of the short pipes 4a, 4b. Therefore, when the second short pipe 4b is pulled in the circumferential direction by the bending wire 7a and rotates 180 degrees, it is bent at an angle of 45 degrees with respect to the first short pipe 4a. Since the first short pipe 4a is bent at 45 degrees with respect to the guide pipe 3 as described above, the second short pipe 4b is ultimately oriented at a right angle with respect to the guide pipe 3. In other words, it faces in a nearly horizontal direction.

[0033] When the short pipes 4a, 4b are bent or curved in this way relative to the guide pipe 3, they will be bent or curved in the soil S, but since the soil S into which the chemical solution has been injected is not yet solidified and is in a fluid and soft state at the time of sample collection, the short pipes 4a, 4b can be easily bent or curved. The dimension to the tip openings of the horizontally oriented short pipes 4a, 4b can be set to a dimension extending horizontally that is equal to or greater than the radius of the borehole 1.

[0034] After the guide tube 3 is set in this way, the sampling tube 13 is inserted from its upper end. First, a flexible pipe is inserted, and then a pipe with a certain degree of rigidity is connected to the rear of it, and the sampling tube 13 is lowered into the guide tube 3. In this case, when using the insertion device 14 shown in FIG. 5, the pipe with a certain degree of rigidity is clamped by the rotary clamp mechanism 18, and in this state, the driving roller 18a is rotated to rotate the sampling tube 13, and at the same time, the rotary clamp mechanism 18 is gradually lowered to lower the sampling tube 13. Therefore, at the part of the short tubes 4a and 4b that is bent from the nearly vertical direction to the horizontal direction, the tip of the sampling tube 13 slides circumferentially along the inner circumferential surface of the short tubes 4a and 4b, so that even if there is a slight step inside the short tubes 4a and 4b, the tip of the sampling tube 13 advances inside them without getting caught. In addition, it bends smoothly along the inner surface of the short tubes 4a and 4b.

[0035] When the sampling tube 13 is further fed by connecting pipes having a certain degree of rigidity, its tip protrudes from the tip opening of the short pipes 4a and 4b and proceeds toward the location where the sample is to be sampled. The length of the short pipes 4a and 4b (the length in the radial direction of the borehole 1) can be made sufficiently long without being restricted by the radius of the borehole 1 as described above. Therefore, the sampling tube 13 curved at the portion from the base pipe 5 to the short pipes 4a and 4b is held horizontally and linearly by the short pipe 4b at the tip side, and then protrudes from the open end. In this way, at the point protruding from the open end, the influence of stress caused by bending following the short pipes 4a and 4b is almost eliminated, so the sampling tube 13 is inserted into the soil S in an almost horizontal direction (the direction in which the open end of the short pipe 4b faces) without the open end being bent downward.

[0036] After inserting the sampling tube 13 to the location where the sample is to be collected, the sampling tube 13 is connected to the sampling box 22 described above, and air is sucked from inside the sampling box 22 by the vacuum pump 20, so that the soil S is sucked up into the sampling box 22 through the sampling tube 13. After the required amount of soil S sample has been collected in this manner, the sampling tube 13 is pulled up and removed from the guide tube 3. The pulling up of the sampling tube 13 or removal from the guide tube 3 can be performed by clamping the sampling tube 13 with the rotating clamp mechanism 18 described above, and in this state pushing up the rotating clamp mechanism with an air cylinder. Alternatively, it can be performed manually.

[0037] At this stage, each of the short pipes 4a, 4b is bent in the horizontal direction, and its tip portion protrudes horizontally beyond the radius of the borehole 1. Therefore, in order to remove the guide pipe 3 from the borehole 1, first, each of the short pipes 4a, 4b is returned to the state in which it extends in the extension direction of the guide pipe 3. That is, the switching valve 21 is operated to pull down the rod 11a of the cylinder 11. Then, the return wire 7b is pulled and the bending wire 7a is loosened, so that each of the short pipes 4a, 4b rotates so that the connecting portions 9a, 9b of the first short pipe 4a and the connecting portion 10b of the second short pipe 4b are aligned in a straight line with respect to the return connecting portion 8b provided on the guide pipe 3. Then, because the rotary joint portions 6a, 6b connecting them are inclined as described above, each of the short pipes 4a, 4b returns to the direction in which it extends in the extension direction of the guide pipe 3. Thereafter, the guide pipe 3 is pulled up from the borehole 1 using an appropriate heavy machine (not shown) or the like.

[0038] As described above, in the device according to the present invention, the mechanism for bending the sampling pipe 13 in the horizontal direction is composed of a plurality of short pipes 4a, 4b connected in sequence by rotary joints 6a, 6b that rotate in a plane inclined at a predetermined angle with respect to the central axis of the guide pipe 3, and is configured to rotate the short pipes 4a, 4b by wires 7a, 7b that pull and relax in the axial direction (longitudinal direction) of the guide pipe 3, bending them relative to the guide pipe 3, and returning them to their original state. Therefore, since there is no portion that protrudes significantly in the radial direction of the guide pipe 3, it is not necessary to increase the diameter of the borehole 1 due to the sampling of samples. In other words, even a small-diameter borehole 1 can be used to sample samples. In addition, since the outer diameter or projected area in the axial direction of the guide pipe 3 is small, the resistance when inserting the guide pipe 3 into the borehole 1 containing unconsolidated soil S is small, and the guide pipe 3 can be easily inserted (built into) the borehole 1. As a result, it is possible to reduce the construction period and costs of the ground improvement work as a whole. Furthermore, the length of the short pipes 4a, 4b that are bent horizontally relative to the guide pipe 3 is not particularly restricted by the inner diameter of the borehole 1, and can be lengthened as necessary. As a result, the length of the portion that guides the sampling pipe 13 to be inserted inside in the horizontal direction can be lengthened, so that the sampling pipe 13 fed out from the tip opening of the short pipe 4b can be fed out horizontally without being affected by stress at the bent portion and bending downward at the point where it leaves the tip opening. In other words, the sampling pipe 13 can be accurately inserted into the place where the sample should be collected.

[0039] On the other hand, in the configuration of the above-mentioned embodiment, since only one sampling tube 13 is inserted into the inside of the guide tube 3, there is little restriction on the thickness, and therefore the sampling tube 13 can be made thicker to quickly and efficiently sample. In addition, the insertion and pulling up of the sampling tube 13, bending and returning of the short tubes 4a and 4b, and suction of the sample can be performed by the insertion device 14. The insertion device 14 is unitized by mounting an air compressor 19 and a vacuum pump 20, and is configured to be movable by casters 15, so that a series of operations such as inserting the sampling tube 13 and vacuum suction can be performed by moving it appropriately to the location where the sample is to be sampled. In other words, the arrangement of the sample collection, the sampling operation, and removal can be simplified or made more efficient. The insertion device 14 may further be provided with a loading platform for mounting necessary equipment such as a synthetic resin pipe to be added to form the sampling tube 13.

[0040] The present invention is not limited to the above-described embodiment, and it is sufficient that a plurality of short pipes and rotary joints are provided to be bent relative to the guide pipe. In this case, if the total inclination angle of the rotary joints is 45 degrees, the short pipe as a whole can be bent at a right angle, or the short pipe as a whole can be bent at an angle twice the total inclination angle. In addition, a minimum of two filaments are used to move the pipe between the bent state and the straight pipe return state, but the number of filaments is not particularly limited, and the pipes may be connected to each other as appropriate, without connecting the multiple connecting parts in series. [Explanation of symbols]

[0041] 1 Borehole 2. Iron Plate 3 Guide tube 4 short tube 4a,4b short tube 5 Base tube part 6a, 6b Rotary joint part 7a Bending Wire 7b Return wire 8a Bending connection 8b Return connection part 9a,9b,10a,10b Connection part (driven connection part) 11 Cylinders 11a Rod 12 Pulley 13 Collection tube 14 Insertion device 15 Caster 16 Frames 17 Guide post 18 Rotating clamp mechanism 18a Drive roller 18b Guide roller 18c Opening and closing lever 18d Motor 19 Air Compressor 20 Vacuum Pump 21 Switching valve 21a Input port 21b, 21c output ports 21d Open Port 22 Collection Box S Soil

Claims

1. An unconsolidated soil sampling device comprising: a guide pipe to be inserted into a borehole excavated for ground improvement; and a flexible sampling pipe that is inserted into the guide pipe from its upper portion and is pushed from the lower end of the guide pipe into soil that has been softened by injecting a chemical solution, the device sampling the unconsolidated soil through the sampling pipe, A plurality of short pipes are connected to the tip end of the guide pipe via rotary joints arranged in sequence in the longitudinal direction of the guide pipe, the rotary joint portion is configured to rotate within a plane that is inclined at a predetermined inclination angle other than perpendicular to a central axis of the guide pipe or the short pipe, A bending joint portion and a return joint portion are provided at different positions in a circumferential direction on an outer periphery of the guide pipe, A driven connecting portion is provided on an outer periphery of each of the short pipes, the driven connecting portion being connected to at least one of the bending connecting portion and the return connecting portion, a bending umbilical member connecting the bending connecting portion to any one of the driven connecting portions in the short pipe, and a return umbilical member connecting the return connecting portion to any one of the driven connecting portions including the other driven connecting portion in the short pipe, The driven connection parts connected by the bending umbilical cord are pulled by the bending umbilical cord so as to approach the bending connection parts of the guide tube, thereby rotating the rotary joint part and bending each of the short tubes relative to the guide tube, and the driven connection parts connected by the return umbilical cord are pulled by the return umbilical cord so as to approach the return connection parts of the guide tube, thereby rotating the rotary joint part and returning each of the short tubes from a bent state relative to the guide tube to a straight state. An unconsolidated soil sample collection device.

2. 2. The unconsolidated soil sampler according to claim 1, the short pipe includes a first short pipe connected to the guide pipe by a first rotary joint portion, and a second short pipe connected to the first short pipe by a second rotary joint portion, the first rotary joint portion is configured to rotate the guide pipe and the first short pipe relative to each other within a plane inclined at a first predetermined angle less than 45 degrees with respect to a central axis of the guide pipe, the second rotary joint portion is configured to rotate the first short pipe and the second short pipe relative to each other within a plane inclined at an angle obtained by subtracting the first predetermined angle from 45 degrees with respect to a central axis of the first short pipe, The bending joint portion and the return joint portion are provided at positions rotated 180 degrees relative to each other in a circumferential direction of the guide tube, the driven connecting portion is provided on an outer periphery of the first short tube, through which the bending umbilical member and the return umbilical member penetrate; The first short tube has an outer periphery provided with a bending driven connection portion to which the bending filament is fixed and a return driven connection portion to which the return filament is fixed, the driven connection portions being spaced apart by 180 degrees from each other in the circumferential direction of the first short tube. An unconsolidated soil sample collection device.

3. 3. The unconsolidated soil sample collection device according to claim 1 or 2, A cylinder for extending and retracting a rod is attached to the outer periphery of the guide tube in parallel with the guide tube, The bending umbilical member and the return umbilical member are connected to the rod, The rod is configured to extend and retract so as to pull one of the bending umbilical member and the return umbilical member and relax the other, thereby bending the short tube relative to the guide tube, or returning the short tube that is bent relative to the guide tube to an orientation in which it is positioned in a straight line relative to the guide tube. An unconsolidated soil sample collection device.

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