Pile hole penetration tester

Abstract

To provide a pile hole penetration tester that can perform measurement tests normally even when the depth of the ground being measured is great. [Solution] An inner casing 3, which is held upright and downright within an outer casing 2, is provided with a penetration rod 6 together with a knocking block 37. The inner casing 3 is provided with a guide section 35 and a weight 38 which is provided upright and downright on the guide section 35 and strikes the knocking block 37. Furthermore, the inner casing 3 is provided with a geared motor 30 and a first pulley 31, a second pulley 32, a first drive belt 33, and a second drive belt 34 which promote the up and down movement of the weight 38 by the drive of the geared motor 30.

Description

Technical Field

[0001] The present invention relates to a penetration tester for pile holes.

Background Art

[0002] Conventionally, as a penetration tester for pile holes, for example, the one described in Patent Document 1 is known. The invention described in this Patent Document 1 is configured as follows.

[0003] That is, in a conventional penetration tester for pile holes, a vertically cylindrical inner casing is held vertically movably inside a vertically cylindrical outer casing. And a penetration rod hanging down from the lower end of the inner casing penetrates the lower end portion of the outer casing and protrudes downward to the outside, and a knocking block integrating the penetration rod is fixed to the lower end portion of the inner casing, and inside the inner casing, a drive hammer for striking the knocking block by free fall is provided. And further, a lifting mechanism for lifting the drive hammer after falling and lowering it at a predetermined height is provided, and it is configured to measure the support strength from the number of strikes of the drive hammer required for the penetration rod to penetrate from the hole bottom to a predetermined depth. The lifting mechanism is composed of a hydraulic cylinder arranged at the upper part inside the inner casing, a slide guide frame provided at the tip of a piston rod protruding downward from the hydraulic cylinder, a pair of clamping pieces held slidable in the radial direction on the slide guide frame, a spring member for urging both clamping pieces in the approaching direction of each other, and a clamp release member provided on the upper side inside the inner casing. And the lifting mechanism configured in this way clamps and holds a gripping portion protruding from the drive hammer between both clamping pieces, lifts the drive hammer by the shortening operation of the piston rod, and both clamping pieces pressed against the clamp release member at the upper limit position are separated against the urging of the spring member to release the drive hammer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] By the way, although the above-mentioned pile hole penetration testing machine can provide a pile hole penetration testing machine with excellent operational stability and durability of the lifting mechanism, it had the following problems.

[0006] The above-mentioned pile hole penetration tester uses a hydraulic cylinder to operate the lifting mechanism. As the depth of the ground being measured increases (for example, to 50m), the hydraulic hose that supplies hydraulic pressure to the hydraulic cylinder sags. When the hydraulic hose sags, the pressure decreases when hydraulic pressure is supplied to the hose, which can cause the lifting mechanism to malfunction. This can lead to problems in conducting the measurement test correctly.

[0007] Therefore, in view of the above problems, the present invention aims to provide a pile hole penetration tester that can perform measurement tests normally even when the depth of the ground being measured is increased. [Means for solving the problem]

[0008] The object of the present invention described above is achieved by the following means. The reference numerals in parentheses indicate the embodiments described later, but the present invention is not limited thereto.

[0009] According to the invention of claim 1, in a pile hole penetration test machine (1) in which a penetration rod (6) is provided together with a knocking block (37) in an inner casing (3) that is held vertically within an outer casing (2), The inner casing (3) includes: Guide section (35), A weight (38) is provided on the guide section (35) so as to be able to move up and down, and strikes the knocking block (37), Motor (geared motor 30), The device is characterized in that it is provided with at least an operating mechanism (first pulley 31, second pulley 32, first drive belt 33, second drive belt 34) that facilitates the raising and lowering of the weight (38) by the drive of the motor (geared motor 30).

[0010] According to the invention of claim 2, in the pile hole penetration test machine (1) described in claim 1, the operating mechanism is A first pulley (31) is connected to the motor (geared motor 30) via a first drive belt (33), It has a second pulley (32) connected to the first pulley (31) via a second drive belt (34), The first pulley (31) and the second pulley (32) are characterized in that they are positioned parallel to the upward and downward direction of the weight (38).

[0011] According to the invention of claim 3, in the pile hole penetration tester (1) described in claim 2, the weight (38) is provided with a locking portion (38a), The second drive belt (34) is provided with a locking portion (34a) that can be locked to the locking portion (38a), The invention is characterized in that when the locked portion (34a) is locked to the locking portion (34), the weight (38) rises along the guide portion (35), and when the locked portion (34a) is released from the locking of the locking portion (34), the weight (38) descends along the guide portion (35). [Effects of the Invention]

[0012] Next, the effects of the present invention will be described with reference to the reference numerals in the drawings. Note that the reference numerals in parentheses are those of embodiments described later, but the present invention is not limited thereto.

[0013] According to the invention of claim 1, a weight (38) that strikes the knocking block (37) is provided on the guide section (35) so as to be able to move up and down, and is moved up and down by an operating mechanism (first pulley 31, second pulley 32, first drive belt 33, second drive belt 34) driven by a motor (geared motor 30). Therefore, since there is no need to use a hydraulic cylinder as in the conventional method to move the weight (38) up and down, the problems that occurred in the conventional method do not occur.

[0014] Therefore, according to the present invention, even if the depth of the ground (G) being measured increases, the measurement test can be performed normally.

[0015] According to the invention of claim 2, the mechanism of the operating mechanism is simplified, which significantly improves the working time for measurement tests.

[0016] According to the invention of claim 3, the raising and lowering of the weight (38) can be facilitated in a simple and easy manner. [Brief explanation of the drawing]

[0017] [Figure 1] This is a front cross-sectional view of a pile hole penetration tester according to one embodiment of the present invention. [Figure 2] This is an explanatory diagram illustrating a method for lowering a weight according to the same embodiment, where (a) shows the state in which the weight has risen to the position of the stopper, and (b) shows the state in which the weight has descended from the position in (a) to the position of the knocking block. [Figure 3] This is an explanatory diagram illustrating a method for raising a weight according to the same embodiment, wherein (a) shows the state in which the weight is about to rise from the position of the knocking block, and (b) shows the state in which the weight is about to rise to the position of the stopper. [Figure 4] The following diagram illustrates the operation of the pile hole penetration test machine according to the same embodiment during a penetration test: (a) shows the state in contact with the bottom of the hole, (b) shows the state at the start of the test, and (c) is a front view showing the state in which the penetration rod has penetrated the ground at the bottom of the hole.

Best Mode for Carrying Out the Invention

[0018] <Explanation of the Borehole Penetration Tester> Hereinafter, an embodiment of the borehole penetration tester according to the present invention will be specifically described with reference to the drawings. In the following description, when indicating the up, down, left, and right directions, it shall refer to the up, down, left, and right as viewed from the front shown in the drawings.

[0019] As shown in FIG. 1, the borehole penetration tester 1 according to the present embodiment includes a vertically cylindrical outer casing 2. As shown in FIG. 1, in the central position of the upper part 2a of this outer casing 2, an attachment portion 20 having a vertically long semi-elliptical shape in a front view and facing upward in the drawing is integrally provided. Further, as shown in FIG. 1, on the upper part 2a of the outer casing 2, on the left side of the attachment portion 20 in the drawing, a power cord adapter 21 is provided.

[0020] On the other hand, as shown in FIG. 1, on the lower part 2b of the outer casing 2, leg portions 22 having a vertically long rectangular shape in a front view are integrally provided on the left side surface 2c side and the right side surface 2d side, respectively. Further, as shown in FIG. 1, on the left side surface 2c and the right side surface 2d of the outer casing 2, stabilizers 23 having a horizontally long semi-circular shape in a front view project outward and are integrally provided.

[0021] Thus, inside the outer casing 2 configured as described above, as shown in FIG. 1, a vertically cylindrical inner casing 3 is loaded concentrically and is movable up and down. Inside this inner casing 3, as shown in FIGS. 1 to 3, a geared motor 30 is attached and fixed to the inner wall surface on the left side surface 3d side of the upper part 3a of the inner casing. Note that, as shown in FIGS. 1 to 3, a power cord 4 for supplying power to the geared motor 30 is connected to this geared motor 30 via the power cord adapter 21.

[0022] Furthermore, as shown in Figures 1 to 3, a first pulley 31 is attached and fixed to the inner wall surface on the right side 3c of the upper 3a side of the inner casing 3. A second pulley 32 is also attached and fixed to the inner wall surface on the right side 3c of the lower 3b side of the inner casing 3, as shown in Figures 1 to 3. Note that, as shown in Figures 1 to 3, the first pulley 31 and the second pulley 32 are spaced apart so that they are parallel in the vertical direction shown in the figures.

[0023] On the other hand, as shown in Figures 1 to 3, a first drive belt 33, formed by a chain or the like, is wound between the geared motor 30 and the first pulley 31. Furthermore, as shown in Figures 1 to 3, a second drive belt 34, formed by a chain or the like, is wound between the first pulley 31 and the second pulley 32. As a result, when the geared motor 30 is driven to rotate, the first pulley 31 rotates via the first drive belt 33, and when the first pulley 31 rotates, the second pulley 32 rotates via the second drive belt 34.

[0024] On the other hand, as shown in Figures 1 to 3, a guide portion 35, which is slender and rod-shaped in a front view, is provided at the center of the inner casing 3, extending in the vertical direction shown in the figure from the upper inner wall surface 3a to the lower inner wall surface 3b. This guide portion 35 is provided so as to be parallel to the position between the first pulley 31 and the second pulley 32, as shown in Figures 1 to 3.

[0025] As shown in Figures 1 to 3, the upper part 35a of the guide portion 35 is attached and fixed to a stopper 36 which has an inverted trapezoidal shape when viewed from the front. The stopper 36 is attached and fixed to the inner wall surface on the upper part 3a side of the inner casing 3, as shown in Figures 1 to 3.

[0026] On the other hand, as shown in Figures 1 to 3, the lower part 35b of the guide section 35 is attached and fixed to a knocking block 37 which is rectangular in front view. This knocking block 37 is attached and fixed to the lower part 3b side of the inner casing 3, as shown in Figures 1 to 3.

[0027] Thus, as shown in Figures 1 to 3, a weight 38 is provided in the guide section 35 configured as described above so as to be able to move up and down. More specifically, as shown in Figures 1 to 3, the weight 38 is provided in the guide section 35 located between the stopper 36 and the knocking block 37 so as to be able to move up and down. As a result, the weight 38 rises to the position of the stopper 36, as shown in Figure 2(a), and descends to the position of the knocking block 37, as shown in Figure 2(b).

[0028] Incidentally, this weight 38 is formed with a mass of 63.5 ± 0.5 kg in accordance with the standard penetration test specified in JIS A 1219, and as shown in Figures 1 to 3, recessed locking portions 38a are provided on the upper side of the left and right sides when viewed from the front. As shown in Figure 3, a rectangular locking portion 34a, which is integrally provided on the second drive belt 34 and protrudes outward, can be locked into this locking portion 38a. Thus, as shown in Figure 3, when the locking portion 34a is locked into the locking portion 38a, the weight 38 rises along the guide portion 35 due to the rotation of the second drive belt 34. On the other hand, as shown in Figure 2, when the locking portion 34a is released from the locking portion 38a, as shown in Figure 2(b), the weight 38 descends along the guide portion 35 due to its own weight.

[0029] Thus, the various components described above are provided inside the inner casing 3.

[0030] Incidentally, as shown in Figures 1 to 3, an encoder 5 is attached and fixed to the inner wall surface of the upper part 2a of the outer casing 2. And, as shown in Figures 1 to 3, a measurement cord 5a extending from this encoder 5 is attached and fixed to the center of the upper part 3a of the inner casing 3. As a result, the encoder 5 can measure the amount of downward movement of the inner casing 3 relative to the outer casing 2.

[0031] On the other hand, as shown in Figures 1 to 3, a penetration rod 6 is provided in the lower part 3b of the inner casing 3. More specifically, as shown in Figure 1, the penetration rod 6 is formed in a slender rod shape when viewed from the front, extending in the vertical direction as shown in the figure. The upper part 6a of this penetration rod 6 is penetrated into the knocking block 37, as shown in Figure 1. Thus, in this state, when the fixing ring 7 shown in Figures 1 and 3 is screw-fastened to the penetration rod 6 and the knocking block 37, the penetration rod 6 is provided in the lower part 3b of the inner casing 3.

[0032] On the other hand, as shown in Figure 1, the lower part 6b of the penetration rod 6 is provided to protrude outward through the accumulator 8 located in the outer casing 2. Furthermore, a split sampler 6b1 for collecting geological samples is provided at the tip of the lower part 6b of the penetration rod 6, as shown in Figure 1.

[0033] Incidentally, the accumulator 8 is under high pressure due to the sealing of compressed air inside. This accumulator 8 prevents mud and soil from entering the outer casing 2 through the penetration portion of the penetration rod 6 during excavation, and is bolted to the lower part 2b of the outer casing 2 as an independent component. As shown in Figure 1, the penetration rod 6 is airtightly inserted through the openings at the upper part 8a and lower part 8b of the accumulator 8 via bearing members 8c and 8d with inner circumference O-rings. As shown by the dashed line in Figure 1, the lower end of the inner casing 3, i.e., the knocking block 37, abuts against the upper bearing member 8c. As a result, the lower limit position of the inner casing 3 within the outer casing 2 is at this position.

[0034] The above describes the pile hole penetration tester 1 according to this embodiment.

[0035] <Explanation of the use of a pile hole penetration tester> Next, an example of using the pile hole penetration tester 1 according to the above embodiment will be described.

[0036] In measuring the bearing strength of the ground at the bottom of a hole using the pile hole penetration test machine 1, first, the mounting portion 20 of the outer casing 2 is fitted and pinned into the lower end opening (not shown) of the Kelly bar K held by the earth drill machine (not shown), as shown in Figure 4(a). This connects the pile hole penetration test machine 1 to the lower end of the Kelly bar K. In this connected state, the pile hole penetration test machine 1 is supported by the Kelly bar K on the outer casing 2 side, so the inner casing 3 is positioned at the lower limit within the outer casing 2 by its own weight, as shown in Figure 4(a). As a result, as shown in Figure 4(a), the protruding length of the penetration rod 6 from the lower part 2b (see Figure 1) of the outer casing 2 is maximized.

[0037] Thus, the pile hole penetration tester 1 connected to the lower end of the Kelly bar K lowers the Kelly bar K without rotation, inserting it into the previously formed pile hole H as shown in Figure 4(a), and lowering it so as not to contact the hole wall, until the tip of the penetration rod 6 abuts against the hole bottom Ha. However, as shown in Figure 4(a), when the tip of the penetration rod 6 abuts against the hole bottom Ha, the lowering of the inner casing 3 stops. However, since the outer casing 2 can move up and down relative to the inner casing 3, the penetration rod 6 retracts into the outer casing 2 as shown in Figure 4(b), causing the outer casing 2 to lower together with the Kelly bar K. Then, as shown in Figure 4(b), when the leg portion 22 provided on the outer casing 2 abuts against the hole bottom Ha, the lowering of the outer casing 2 and the Kelly bar K stops, and the protruding length of the penetration rod 6 from the lower part 2b of the outer casing 2 (see Figure 1) becomes the minimum. In this state, the Kelly bar K is fixed in a position where it cannot be raised or lowered, and the following measurement test is performed using the pile hole penetration test machine 1.

[0038] In the measurement test, first, the geared motor 30 shown in Figure 2(a) is driven to rotate. This causes the first pulley 31 to rotate via the first drive belt 33, and as the first pulley 31 rotates, the second pulley 32 rotates via the second drive belt 34. As a result of this rotation, the second drive belt 34 moves in the direction of arrow Y1, as shown in Figure 2(a). Consequently, the locked portion 34a, which was locked to the locking portion 38a, as shown in Figure 2(a), is released from the locking, as shown in Figure 2(b). Consequently, the weight 38 descends along the guide portion 35 by its own weight, as shown in Figure 2(b) (see arrow Y2). Thus, this descent causes the weight 38 to strike the knocking block 37, as shown in Figure 2(b). This impact force causes the inner casing 3 to descend, and the penetration rod 6 penetrates the ground G at the bottom of the hole Ha, as shown in Figure 4(c).

[0039] Meanwhile, as the second drive belt 34 moves further, the locked portion 34a locks back into the locking portion 38a, as shown in Figure 3(a). Thus, as shown in Figure 3(a), when the second drive belt 34 moves in the direction of arrow Y3 (upward direction in the illustration), the locked portion 34a moves in the direction of arrow Y3 (upward direction in the illustration) while remaining locked into the locking portion 38a. As a result, as shown in Figure 3(b), the weight 38 rises along the guide portion 35 and rises to the position of the stopper 36, as shown in Figure 2(a). Then, as described above, the locked portion 34a, which was locked into the locking portion 38a, is released from the lock, as shown in Figure 2(b), and the weight 38 strikes the knocking block 37.

[0040] Thus, the above process is repeated in the same manner thereafter, and the striking operation is repeated. In this way, the number of strikes required for the penetration rod 6 to penetrate from the bottom of the hole Ha to a predetermined depth is measured, and based on the number of strikes, it is determined whether or not the bearing strength of the ground G at the bottom of the hole Ha is equal to or greater than a predetermined value.

[0041] Incidentally, the number of blows (N value) of the weight 38 can be calculated by checking the rotation speed of the geared motor 30, as the position of the locked portion 34a can be determined by the rotation speed of the geared motor 30. The amount of penetration of the penetration rod 6 into the ground G at the bottom of the hole Ha is measured by the encoder 5 as the amount of descent of the inner casing 3. This measurement signal from the encoder 5 is sent to an automatic measuring device on the ground (not shown), where the settlement amount per blow, i.e., the amount of penetration of the penetration rod 6 into the ground G, and the cumulative penetration amount are recorded and displayed along with the number of blows (N value). In the standard penetration test specified in JIS A1219, a weight 38 with a mass of 63.5 ± 0.5 kg is dropped from a free height of 76 ± 1 cm to strike a knocking block 37, and the number of blows required for a penetration rod 6 with an outer diameter of 51 ± 1 mm and an inner diameter of 35 ± 1 mm to penetrate 30 cm into the ground is expressed as the N value. Therefore, in this pile hole penetration testing machine 1, the bearing strength can be determined as the N value in accordance with the above standard penetration test.

[0042] Therefore, the measurement test will be conducted in this manner.

[0043] The above describes an example of how to use the pile hole penetration tester 1 according to this embodiment.

[0044] Therefore, by using the pile hole penetration test machine 1 described above, there is no need to use a hydraulic cylinder to raise and lower the weight 38 as in the conventional method, and thus the problems that occurred in the conventional method do not occur. For this reason, according to this embodiment, even if the depth of the ground G to be measured is great, the measurement test can be performed normally.

[0045] <Explanation of variations> The above-described details constitute the pile hole penetration tester 1 and its usage examples in this embodiment. However, the shapes and other features shown in this embodiment are merely examples, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. For example, in this embodiment, an example is shown in which the mechanism of the first pulley 31, the second pulley 32, the first drive belt 33, and the second drive belt 34 is used to promote the raising and lowering of the weight 38, but it is not limited to this, and any mechanism that can promote the raising and lowering of the weight 38 in conjunction with the rotational drive of the geared motor 30 is acceptable. However, it is preferable to use a mechanism like the one shown in this embodiment. This is because such a mechanism is simpler than conventional mechanisms in which the drive hammer is clamped, lifted, released, and then clamped again, thus significantly improving the working time for measurement tests.

[0046] Furthermore, in this embodiment, a locking portion 34a is provided on the second drive belt 34, and a locking portion 38a is provided on the weight 38, and an example is shown in which the lifting and lowering of the weight 38 is facilitated by whether or not the locking portion 34a is locked to the locking portion 38a. However, the embodiment is not limited to this, and any configuration that can facilitate the lifting and lowering of the weight 38 is acceptable. Nevertheless, the configuration shown in this embodiment is preferred. This is because such a configuration makes it easy and simple to facilitate the lifting and lowering of the weight 38.

[0047] Furthermore, although this embodiment shows an example in which one mechanism consisting of a geared motor 30, a first pulley 31, a second pulley 32, a first drive belt 33, and a second drive belt 34 is provided, multiple such mechanisms may be provided.

[0048] Furthermore, although this embodiment shows an example in which one locking portion 34a is provided on the second drive belt 34, it is not limited to this, and multiple locking portions may be provided.

[0049] Furthermore, although a geared motor 30 is used as an example in this embodiment, the motor is not limited to this, and any type of motor may be used. [Explanation of Symbols]

[0050] 1. Penetration testing machine for pile holes 2. Outer casing 3. Inner casing 6 Penetration Rods 30 Geared motors (motors) 31. First pulley (operating mechanism) 32. Second pulley (operating mechanism) 33. First drive belt (operating mechanism) 34. Second drive belt (operating mechanism) 34a Locked part 35 Guide section 37 Knocking Block 38 Weight 38a Locking part G Ground

Claims

1. In a pile hole penetration test machine, an inner casing is held vertically within an outer casing, and a penetration rod is provided therein along with a knocking block. The inner casing includes: Guide section, The guide portion is provided with a weight that can move up and down and strikes the knocking block, Motor and, A pile hole penetration tester is provided, which includes at least an operating mechanism that promotes the raising and lowering of the weight by driving the motor.

2. The aforementioned operating mechanism is A first pulley is connected to the motor via a first drive belt, It has a second pulley connected to the first pulley via a second drive belt, The pile hole penetration tester according to claim 1, wherein the first pulley and the second pulley are positioned parallel to the upward and downward direction of the weight.

3. The aforementioned weight is provided with a locking mechanism. The second drive belt is provided with a locking portion that can be locked to the locking portion, The pile hole penetration tester according to claim 2, wherein when the locked portion is locked to the locking portion, the weight rises along the guide portion, and when the locked portion is released from the locking portion, the weight descends along the guide portion.

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