Rod joint structure of ground investigation equipment

Abstract

To provide a joining structure of a rod of a ground survey device capable of easily and safely attaching and detaching the rod even in a state where a load in a vertical direction acts on the rod.SOLUTION: A joining structure of a rod of a ground survey device in which the rod is penetrated into the ground when the target ground is investigated includes: a joining member 4 whose cap part 41 covering an upper end jig 221 of the rod 22 is provided at the lower end; and a pin part 5 which is inserted in a direction orthogonal to an axial direction of the rod so as to be engaged with the cap part and the upper end jig. This pin part is arranged along a pair of concave parts 221a provided on the peripheral surface of the upper end jig.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rod joint structure of a ground investigation device that penetrates a rod into ground when investigating a target ground. [Background technology]

[0002] In conventional general ground investigations, in the case of small-scale buildings, ground constants related to the strength of the ground are obtained by in-situ tests such as Swedish Weight Sounding (SWS) tests. Then, the study of the ground's bearing capacity against long-term loads is carried out based on these ground constants.

[0003] The SWS test is an investigation method that evaluates the hardness of the ground by measuring the penetration resistance of a rod equipped with a weight. The ground investigation equipment used for this test has been automated in recent years, and automated equipment for loading and unloading the weight, rotation control, and measurement are also becoming widespread.

[0004] On the other hand, the SWS test determines the penetration resistance, and there are many issues with its accuracy. Patent Document 1 proposes a method of obtaining highly accurate information by using a penetration tester and applying vibration to it.

[0005] Here, when trying to confirm the dynamic penetration amount and load by using a vibration exciter to apply vibration using a penetration testing machine for SWS tests as is, as in the method disclosed in Patent Document 1, if a displacement meter or load meter is attached directly to the main body of the device, there is a problem that the vibration will be large and may affect accuracy and durability.

[0006] Therefore, Patent Document 2 proposes a measuring device for ground investigation that is compatible with a wide variety of investigation devices and can perform measurements easily and with high accuracy by attaching a displacement meter or the like as a simple attachment to the middle of the rod. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-17112 A [Patent Document 2] JP 2019-178490 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in general, the rod is designed to be joined at both ends with male and female screws, which makes it difficult to attach and detach the rod when the weight of the vibrator is loaded on the upper end of the rod, and can also increase the danger of the work.

[0009] Therefore, an object of the present invention is to provide a rod joining structure for a ground investigation device that allows the rod to be attached and detached easily and safely even when a vertical load is acting on the rod. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the joint structure of a rod of a ground investigation device of the present invention is a joint structure of a rod of a ground investigation device that penetrates a rod into the ground when investigating a target ground, and is characterized in that it comprises a joint member having a cap portion at its lower end that covers the upper end of the rod, and a pin portion that is inserted in a direction perpendicular to the axial direction of the rod so as to engage with the cap portion and the upper end, and the pin portion is arranged along a pair of recesses provided on the peripheral surface of the upper end or a through hole that penetrates the upper end.

[0011] Here, the upper end portion may be configured to be detachably attached to the main body of the rod. Also, a vibration exciter or the like may be attached to the upper end of the joining member. Effect of the Invention

[0012] The rod joint structure of the ground investigation device of the present invention thus configured comprises a joint member having a cap portion at its lower end that covers the upper end of the rod, and a pin portion that is inserted perpendicular to the axis of the rod so as to engage with the cap portion and the upper end. The pin portion is disposed along a pair of recesses provided on the periphery of the upper end or along a through hole that penetrates the upper end.

[0013] Therefore, even if a vertical load is applied to the rod, the rod can be easily and safely attached and detached by inserting and removing the pin. In the case of a ground investigation device that applies vertical load or vibration to the rod, it is sufficient to restrain vertical movement. Furthermore, if the rod is fixed by the pin, it is possible to ensure the desired performance in terms of strength and durability without causing excessive bending stress to the rod or connecting members.

[0014] In addition, if the upper end is detachably attached to the rod body, various rods, including prefabricated rods, can be used. Even if a vibration exciter is attached to the upper end of the joining member, the rod can be easily and safely attached and detached. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is an explanatory diagram showing the configuration of a joint structure of a rod of the ground investigation device of the present embodiment. [Diagram 2] FIG. 1 is an explanatory diagram showing the overall configuration of a ground investigation device. [Diagram 3] FIG. 2 is an explanatory diagram showing a configuration of a rod. [Figure 4] FIG. 4 is an explanatory diagram showing the positional relationship between the upper end of the rod and a joining member. [Diagram 5] 11A and 11B are explanatory diagrams showing the configuration of another joining member. [Figure 6] FIG. 2 is an explanatory diagram showing the configuration of a joining member according to the first embodiment. [Figure 7] 1 is an explanatory diagram showing the overall configuration of a ground investigation device according to a first embodiment. [Figure 8] 4 is an explanatory view showing the configuration of another joining member of the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A ground investigation using the ground investigation device 1 described in this embodiment is carried out on a target ground G for which a building such as a house is to be constructed. A ground investigation such as a penetration test is usually carried out directly on the target ground G at one or more points.

[0017] For example, in the case of a small-scale building, a Swedish weight sounding test (SWS test) is generally conducted at one or more points on the target ground G. The Swedish weight sounding test is a type of static penetration test specified in JIS A 1221, and is a ground investigation method that estimates the hardness of the ground from the penetration resistance of a rod when screwing a screw point 23 into the ground.

[0018] 2, the penetration test machine 2 is mainly composed of a base machine 21, a rod 22, a screw point 23 attached to the tip (lower end) of the rod 22, a base part 24, and a weight part 25. The base machine 21 is a Swedish sounding test machine that has a proven track record in soil investigations of small-scale buildings.

[0019] On the other hand, weight 25 is used to apply a load stepwise to screw point 23 used in Swedish Weight Sounding (SWS) testing. In SWS testing, the results of the investigation are basically evaluated in 25 cm increments. Rod 22 is composed of unit rods of 1 m or 50 cm connected together. In other words, the measurement is carried out by adding unit rods.

[0020] By attaching a vibration exciter 3 to the penetration testing machine 2 and applying vibrations and impacts, it becomes possible to evaluate the bearing capacity and rigidity of the ground more accurately than with the Swedish sounding test. In order to evaluate the bearing capacity of the ground, accurate measurement data of the applied load and the penetration amount is required.

[0021] That is, it is necessary to accurately measure the dynamic penetration amount and load while the vibration exciter 3 is striking the test object. This measurement can be performed by using the displacement meter and load meter that are originally equipped in the penetration tester 2.

[0022] Furthermore, as described in Patent Document 2, by attaching a sensor such as a strain gauge to a short rod or jig interposed in the rod 22, it is possible to make it into a measuring instrument such as a displacement meter.

[0023] The rod joint structure of the ground investigation device 1 of this embodiment includes a joint member 4 that connects the rod 22, which is inserted into the ground when investigating the target ground G, to a vibration exciter 3 attached to its upper end, as shown in Figure 2.

[0024] In detail, as shown in FIG. 1, the joining member 4 has a cap portion 41 at its lower end which covers an upper end jig 221 which is the upper end of the rod 22, and a pin portion 5 which is inserted so as to engage with the cap portion 41 and the upper end jig 221 in a direction perpendicular to the axial direction of the rod 22.

[0025] The joining member 4 is composed of a cap portion 41 at the lower end, a joint portion 43 at the upper end for connecting the vibrator 3 and the like upward, and an axial connecting portion 42 connecting the cap portion 41 and the joint portion 43.

[0026] The cap portion 41 is formed with a cylindrical inner space 411 that is larger than the outer shape of the cylindrical upper end jig 221. The joint portion 43 is provided with a hole 431 for connecting the vibration exciter 3 and the like.

[0027] 3, the upper end jig 221 of the rod 22 housed in the inner space 411 of the cap part 41 is provided with a pair of recesses 221a, 221a on the circumferential surface. The pair of recesses 221a, 221a are formed at the same height and facing each other on the cylindrical upper end jig 221, and have a semicircular or arc-shaped cross section.

[0028] As shown in FIG. 4, the upper end jig 221 of the rod 22 in this embodiment has a male threaded portion 221b at its lower end, and is configured so as to be freely attached and detached to the female thread provided at the upper end of the main body of the rod 22.

[0029] Here, the upper end jig 221 is attached to the upper end of the rod 22 before connecting it to the vibration exciter 3, and is not removed from the rod 22 while it is connected to the vibration exciter 3 and a load is applied to it. When only one rod 22 is to be inserted, an upper end such as the upper end jig 221 can be provided integrally with the rod 22.

[0030] The pin portion 5 is a cylindrical bar disposed along the recess 221a of the upper end jig 221. The recess 221a is formed in a semicircular shape with a diameter slightly larger than that of the pin portion 5 in cross section.

[0031] A recess having a semicircular or arc-shaped cross section and a diameter the same as or slightly larger than that of the pin portion 5 is formed on the inner peripheral surface of the inner space 411 of the cap portion 41 facing the recess 221a. In other words, the pin portion 5 is inserted into a hole 412 having a circular cross section, which is formed by the recess 221a and the recess on the inner peripheral surface of the cap portion 41 (see FIG. 1).

[0032] The hole 412 thus formed in the cap portion 41 is larger than the outer shape of the pin portion 5, leaving a gap between them, so that the pin portion 5, which is oriented in a direction perpendicular to the axial direction of the rod 22, can be easily inserted and removed. In addition, if the connection is a pin fixation that allows rotation, it is possible to prevent the occurrence of excessive stress due to bending, etc.

[0033] 1, when the pin portion 5 is bridged over the cylindrical inner space 411 of the cap portion 41, the cap portion 41 and the upper end jig 221 are engaged with each other by the pin portion 5, and the relative movement in the vertical direction between the cap portion 41 and the upper end jig 221 is restricted. In other words, with respect to a vertical load, the force can be efficiently transmitted between the cap portion 41 and the upper end jig 221 via the pin portion 5.

[0034] So far, the configuration in which the upper end jig 221 is engaged by a pair of pins 5, 5 arranged to sandwich the upper end jig 221 has been described, but the present invention is not limited to this. For example, as shown in Fig. 5, the engagement can also be achieved by a different configuration of a joining member 4A.

[0035] A through hole 412A having a circular cross section is provided in the center of the cap portion 41A of the joining member 4A so as to communicate with the inner space 411, and one pin portion 5 is inserted into the through hole 412A. That is, a through hole 412A for passing the pin portion 5 in a direction perpendicular to the axis of the rod 22 is also provided in the center of the upper end jig 221A of the rod 22 housed in the inner space 411 of the cap portion 41A.

[0036] Even with the joining member 4A configured in this manner, the pin portion 5 can be easily inserted and removed, and the engagement of the pin portion 5 between the cap portion 41A and the upper end jig 221A allows for efficient transmission of force between the cap portion 41A and the upper end jig 221A.

[0037] Next, a method of investigating the ground using the ground investigation device 1 of this embodiment will be described. FIG. 2 shows a state in which a rod 22 having a screw point 23 at the tip of a first unit rod is penetrated into the target ground G by the simple harmonic motion of the vibration exciter 3 in the vertical direction.

[0038] Specifically, the vibration exciter 3 is connected to the upper end jig 221 of the rod 22 via a joint member 4. When the vibration exciter 3 is operated, the screw point 23 at the tip of the rod 22 is driven into the target ground G.

[0039] When the upper end of the uppermost unit rod is struck by the vibration exciter 3, the rod 22 is gradually pushed into the target ground G, until it becomes necessary to add more unit rods to the lowered rod 22.

[0040] At this time, the operation of the vibration exciter 3 is stopped once and a unit rod is added, but since the weight of the vibration exciter 3 remains loaded on the rod 22, in this state the upper end jig 221 cannot be removed from the main body of the rod 22.

[0041] Therefore, the pin portion 5 is pulled out from the cap portion 41 of the joining member 4 to release the connection between the joining member 4 and the rod 22. Since the pin portion 5 is simply inserted into a hole 412 that is slightly larger than the cap portion 41, it can be easily pulled out in the direction perpendicular to the axis of the rod 22 (horizontal direction).

[0042] Once the connection between the joint member 4 and the rod 22 is released, the vibration exciter 3 can be easily removed together with the joint member 4, since the inner space 411 of the cap portion 41 is formed to be slightly larger than the upper end jig 221.

[0043] Next, the upper end jig 221 exposed at the upper end of the rod 22 is removed, and a new unit rod is added above the rod 22. Then, the upper end jig 221 is screwed onto the upper end of the newly added unit rod, and the cap part 41 of the joining member 4 is placed on the upper end jig 221 to position the vibration exciter 3.

[0044] Furthermore, by inserting the pin portion 5 into the hole 412 of the cap portion 41, the cap portion 41 and the upper end jig 221 are engaged with each other by the pin portion 5. Then, the vibration exciter 3 is operated again to advance the penetration of the rod 22 into the target ground G.

[0045] Next, the operation of the joint structure of the rod of the ground investigation device of this embodiment will be described. The rod joint structure of the ground investigation device 1 of this embodiment configured as described above comprises a joint member 4 having a cap portion 41 at its lower end which covers the upper end jig 221 which is the upper end of the rod 22, and a pin portion 5 which is inserted perpendicular to the axis of the rod 22 so as to engage with the cap portion 41 and the upper end jig 221.

[0046] The pin portion 5 is disposed along a pair of recesses 221a provided on the peripheral surface of the upper end jig 221 or a through hole 412A penetrating the upper end jig 221A, and is thereby bridged over the inner space 411 of the cap portion 41 (41A).

[0047] Therefore, even if a vertical load is applied to the rod 22, the rod 22 can be easily and safely attached and detached by inserting and removing the pin portion 5. In the case of the ground investigation device 1 which applies a vertical load or vibration to the rod 22, it is sufficient to restrain the vertical movement, and by fixing with the pin portion 5, it is possible to easily ensure the desired performance in terms of strength and durability without generating stress such as excessive bending in the rod 22 and the connecting member 4.

[0048] Also, if the upper end jig 221 is provided so as to be detachable from the main body of the rod 22, various rods such as prefabricated unit rods can be used. Even if the vibration exciter 3 is attached to the upper end of the joining member 4, it can be easily and safely attached and detached. EXAMPLES

[0049] Hereinafter, a first embodiment, which is different from the embodiment described above, will be described with reference to Figures 6 to 8. Note that the same terms or the same reference numerals will be used to describe the same or equivalent parts as those described in the embodiment described above.

[0050] In the above embodiment, a description has been given of the configuration of the joint member 4 (4A) that allows the rod 22 to be easily and safely attached and detached even when the load of the vibration exciter 3 is applied. In this Example 1, a description will be given of a joint member 6 (6A) that has a heat dissipation function.

[0051] As described above, when the upper end of the rod 22 is struck by a vibration exciter 3 or the like, friction occurs at the connection point between the joining member 4 (4A) and the vibration exciter 3 and at the connection point between the joining member 4 (4A) and the rod 22, and this can cause the temperature to rise due to continued vibration for a long period of time.

[0052] On the other hand, when measuring the load, it is possible to measure the strain by providing a load measuring section on the joining member, but the commonly used strain gauges are susceptible to temperature effects and can be damaged under excessively high temperatures. In addition, there is a possibility that thermal conduction can cause failure of devices such as displacement meters attached nearby.

[0053] Therefore, in this Example 1, a joining member 6 (6A) having a heat dissipation function will be described. First, the joining member 6 will be described with reference to Fig. 6 and Fig. 7. This joining member 6 is composed of a cap part 61 that covers the upper end part 221B of the rod 22, a joint part 63 at the upper end for connecting the vibrator 3 or the like upward, a heat dissipation part 64, and a connection part 62.

[0054] The joint portion 43 is provided with a hole 631 for connecting the vibration exciter 3, etc. The cap portion 61 is formed with a cylindrical inner space 611 that is larger than the outer shape of the cylindrical upper end portion 221B.

[0055] Although not shown, the connection between the upper end portion 221B and the cap portion 61 can be made in any structure, such as via a pin portion 5 that is inserted so as to engage with the cap portion 61 and the upper end portion 221B in a direction perpendicular to the axial direction of the rod 22, as described above in the embodiment.

[0056] Further, a heat dissipation section 64 for efficiently dissipating heat generated by operation of the vibration exciter 3 is provided below the joint section 63 of the joining member 6 in Example 1. In detail, the heat dissipation section 64 is provided between the connection section 62 and the joint section 63 to which the vibration exciter 3 is connected.

[0057] The heat dissipation section 64 includes a plurality of horizontal fins 641 spaced apart in the vertical direction around a shaft section 640 extending in the extension direction of the connection section 62. The horizontal fins 641 are heat dissipation fins formed in the shape of a ring plate around the cylindrical shaft section 640, for example.

[0058] When the heat generated in the joint portion 63 is transferred toward the connecting portion 62, it is also transferred to the horizontal fins 641 that extend in the horizontal direction via the shaft portion 640. The heat transferred to the horizontal fins 641 is dissipated from the upper and lower surfaces of the horizontal fins 641, so that the amount of heat transferred to the connecting portion 62 is significantly reduced.

[0059] That is, the horizontal fins 641, which have upper and lower surfaces extending in an annular shape and are provided in plurality, increase the surface area of ​​the heat dissipation portion 64, thereby efficiently dissipating heat, and thus the temperature rise of the joining member 6 can be suppressed.

[0060] The form of such heat dissipation fins is not limited to the horizontal fins 641. For example, heat dissipation fins extending in the vertical direction may be provided as in the joint member 6A shown in Fig. 8. That is, a heat dissipation section 64A for efficiently dissipating heat generated by the operation of the vibration exciter 3 is provided below the joint section 63 of the joint member 6A.

[0061] The heat dissipation section 64A includes a plurality of vertical fins 642 spaced apart in the circumferential direction around a shaft section 640 extending in the extension direction of the connecting section 62. The vertical fins 642 are heat dissipation fins formed in the shape of rectangular plates and radially arranged around the cylindrical shaft section 640.

[0062] Even when multiple vertical fins 642 are provided in this manner, when heat generated in the joint portion 63 is transmitted toward the connecting portion 62, it is also transmitted to the vertical fins 642 via the shaft portion 640, and is dissipated from both sides of the vertical fins 642.

[0063] As a result, the amount of heat transferred to the connecting portion 62 is significantly reduced, and the temperature rise of the connecting member 6A can be suppressed. Furthermore, the connecting member 6A also has a reinforcement function against the impact of the vibration exciter 3 by the vertical fins 642.

[0064] That is, not only the shaft portion 640 but also the vertical fins 642 provided around it in the form of ribs can withstand the vertical load transmitted between the joint portion 63 and the connecting portion 62 and the force generated by bending. As a result, the strength and durability against repeated loads can be improved.

[0065] The rod joint structure of the ground investigation device 1 of Example 1 configured as described above is a rod joint structure of the ground investigation device 1 that penetrates the rod 22 into the ground when investigating the target ground G, and is equipped with joint members 6, 6A at the lower end of which is provided with a cap portion 61 that covers the upper end portion 221B of the rod 22, and at the upper end of which is provided with a joint portion 63 to which an exciter 3 or the like is attached.

[0066] The joining members 6, 6A are provided with heat dissipation sections 64, 64A having a plurality of heat dissipation fins such as horizontal fins 641 and vertical fins 642. This makes it possible to suppress the temperature rise of the joining members 6, 6A when the vibrator 3 is operated, and significantly reduces the impact on the measurement accuracy of various measuring instruments and the risk of damage.

[0067] Furthermore, if the joining member 6A is provided with the vertical fins 642, it is possible to improve the strength against bending stress and the durability against repeated loads. Other configurations and functions and effects are substantially the same as those of the above-described embodiment, and therefore description thereof will be omitted.

[0068] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment or example, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0069] For example, in the above embodiment and Example 1, a case has been described in which the vibration exciter 3 is attached to the upper end of the joining members 4, 4A, 6, 6A, but this is not limited to this, and what is attached to the joint part 43, 63 may be a unit rod, a jig equipped with a measuring instrument, a loading part for a weight, etc. [Explanation of symbols]

[0070] 1: Ground investigation equipment 22: Rod 221, 221A: Upper end jig (upper end) 221a: Recess 3: Vibrator 4, 4A: Joint material 412A:Through hole 41, 41A: Cap part 43: Joint part (upper end of joint part) 5: Pin section G: Target ground

Claims

1. A joint structure of a rod of a ground investigation device that penetrates a ground when investigating a target ground, A joining member having a cap portion at a lower end thereof for covering an upper end portion of the rod; a pin portion that is inserted so as to engage with the cap portion and the upper end portion in a direction perpendicular to the axial direction of the rod; The pin portion is disposed along a pair of recesses provided on a peripheral surface of the upper end portion or a through hole penetrating the upper end portion, A joint structure for a rod of a ground investigation device, characterized in that an exciter is attached to the upper end of the joint member, and a heat dissipation section is provided between the exciter and the cap section.

2. A joint structure for a rod of a ground investigation device as described in Claim 1, characterized in that the heat dissipation portion is formed by a plurality of horizontal fins arranged at intervals in the vertical direction around the shaft portion of the joint member.

3. A joint structure for a rod of a ground investigation device as described in Claim 1, characterized in that the heat dissipation portion is formed by a plurality of vertical fins arranged circumferentially spaced around the shaft portion of the joint member.

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