JP6159778B2 - Vibro hammer gripping device and steel pipe pile construction method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a gripping device for gripping or drawing a cylindrical or square tubular steel pipe (steel pipe pile) in a vibro hammer method and a method for constructing a steel pipe pile using the gripping apparatus (hereinafter, “steel pipe” is a steel pipe pile). Used to mean).

  When a steel pipe is directly gripped by a general gripping device of a vibratory hammer, a mechanism for inserting a fixed claw and a movable claw provided on a chuck of the gripping device from the top end and clamping a pipe wall as described in Patent Document 1 is well known. .

  When installation of a general gripping device is difficult due to the small inner diameter of the steel pipe, there is a method in which a chucking plate is welded to the top end of the steel pipe and the chucking plate is gripped by a chuck of the gripping device. Further, as in Patent Document 2, there is a method in which a core body is installed in a pipe and is pressed and held inward from the outside of the pipe. The core body is for preventing deformation of the tube due to the pressing force from the outside of the tube.

  FIG. 9 is a plan view and a longitudinal sectional view schematically showing deformation characteristics of the steel pipe P when a pressing force is applied outwardly in the X direction with respect to the inner surface, taking a cylindrical steel pipe P as an example. Each white arrow indicates a pressing force applied to a different position from the top end of the steel pipe P downward. When the same pressing force is applied at each position, the steel pipe P expands in the X direction near the top end and contracts in the Y direction. The top edge has the largest amount of deformation, and the amount of deformation gradually decreases downward. This deformation is plastic deformation and does not return to its original shape even when the pressing force is removed (hereinafter, the steel pipe is simply referred to as “deformation” means plastic deformation). The same deformation occurs when a pressing force is applied inward to the outer surface. In addition, the deformation | transformation aspect of a steel pipe is not restricted to this, It is various also with the number of the press points of the circumferential direction. Therefore, conventionally, when an attempt is made to grip the steel pipe by applying a pressing force to either the inner surface or the outer surface of the steel pipe, a countermeasure for preventing deformation as in Patent Document 2 has been taken.

  As another example of preventing the deformation of the steel pipe by providing a force that opposes the pressing force for gripping the steel pipe, Patent Document 3 describes that the hollow pile is gripped from the outer periphery, and the gripped portion is located inside the hollow pile. A method of gripping a hollow pile by pressing from the periphery is disclosed. Patent Document 4 discloses a method of gripping a tubular pile by exerting a pressing force outward by the in-pipe pressing means in the vicinity of the top end of the tubular pile and by applying a pressing force inward by the tube external pressing means. Yes.

JP 2012-112224 A JP-A-6-257150 JP-A-57-81529 Japanese Patent Application Laid-Open No. 2014-84641

  A general gripping device of a vibratory hammer is not limited to the case where the inner diameter of the steel pipe is small, and there are cases where the steel pipe cannot be gripped due to various circumstances. In some cases, the chucking plate cannot be welded when it cannot be gripped by a general gripping device (for example, when the drawn steel pipe is diverted to another site). In such a case, it is necessary to apply a pressing force outward from the inside of the pipe of the steel pipe and grip the steel pipe by a tensile force, but it is difficult to provide a counter force for preventing deformation of the steel pipe outside the pipe. There is. For example, when a steel pipe is driven into the ground or when another structure is close to the outside of the steel pipe, a necessary space outside the pipe may not be obtained.

  In addition, when a gripping device for a vibratory hammer is provided with a mechanism for applying a pressing force and its opposing force both inside and outside the steel pipe, the gripping device becomes complicated and bulky, which makes the work and conveyance complicated. Cost increases.

  In view of the above problems, the present invention is a steel pipe gripping device in a vibratory hammer, which can hold a steel pipe by applying a pressing force only from one of the pipe inside or outside the pipe, and to deform the steel pipe. An object of the present invention is to provide a gripping device that does not occur and a steel pipe construction method using the gripping device.

  Here, referring again to FIG. 9, no deformation occurs even for the same pressing force below the point of the predetermined length L1 from the top end of the steel pipe P. Similarly, it is self-evident that no deformation occurs even above the point of the predetermined length L3 (= L1) from the lower end of the steel pipe P. That is, no deformation occurs in the intermediate region L2 excluding the upper end region L1 and the lower end region L3 having a predetermined length from both ends in the length direction of the steel pipe P with respect to the predetermined pressing force in the lateral direction. In the predetermined steel pipe P, the range of the intermediate region L2 in which no deformation occurs with respect to the lateral pressing force is determined by the relationship between the magnitude of the pressing force and the material mechanical properties of the steel pipe P.

  This invention is made | formed based on this knowledge, and provides the following structures. The numbers in parentheses are reference numerals of the drawings described later, and are attached for reference.

An aspect of the present invention is a gripping device (1) of a vibratory hammer (VH) for gripping a steel pipe (P), wherein an excitation force of the vibratory hammer (VH) is transmitted to an upper end and extends downward. Support part (3) and one or more pressing means provided at one or a plurality of places in the extending direction of the support part (3) and capable of generating a pressing force outward with respect to the inner surface of the steel pipe (P) (4), and the pressing force by the one or more pressing means (4) is a magnitude that generates a frictional force capable of gripping the steel pipe (P) when driven or pulled out by the vibratory hammer (VH). And the position where each of the one or more pressing means (4) presses the steel pipe (P) is when there is no resistance against the pressing force in the length direction of the steel pipe (P). Upper end region that causes plastic deformation of a predetermined amount or more by the pressing force (L1) and lies in the intermediate region (L2) excluding the lower end region (L3).

Another aspect of the present invention is a gripping device (1) for a vibratory hammer (VH) for gripping a steel pipe (P), wherein the vibratory force of the vibratory hammer (VH) is transmitted to the upper end and extended downward. One or a plurality of support portions (3) and one or a plurality of the support portions (3) that are provided at one or a plurality of locations in the extending direction of the support portion (3) and can generate a pressing force inward with respect to the outer surface of the steel pipe (P). A pressing means (4), and the pressing force by the one or more pressing means (4) generates a frictional force capable of gripping the steel pipe (P) when driven or pulled out by the vibratory hammer (VH). The position where each of the one or the plurality of pressing means (4) presses the steel pipe (P) has no resistance to the pressing force in the length direction of the steel pipe (P). In some cases, the pressing force causes plastic deformation of a predetermined amount or more. Characterized in that the region (L1) and a lower end region (L3) intermediate region (L2) excluding.

A gripping device (1) for a vibratory hammer (VH) for gripping a steel pipe (P), wherein the vibration generating force of the vibratory hammer (VH) is transmitted to the upper end and extends downward. One or a plurality of pressing means (4) provided at one or a plurality of locations in the extending direction of the support portion (3) and capable of generating a pressing force outward with respect to the inner surface of the steel pipe (P), And the pressing force by the one or more pressing means (4) has such a magnitude as to generate a frictional force capable of gripping the steel pipe (P) when being pulled by the vibratory hammer (VH), and The position where each of the plurality of pressing means (4) presses the steel pipe (P) is not less than a predetermined amount by the pressing force when there is no resistance against the pressing force in the length direction of the steel pipe (P) . Upper end region (L1) and lower end region (L ) In the area (L2, L3), excluding the upper end region (L1) of, and at least one of the pushing pressure position is characterized in that in the lower end region (L3).

  In the above aspect, the pressing means (4, 4A) is composed of a combination of one or more fixed claws (41) and one or more movable claws (42), or is composed of a plurality of movable claws (42). Is preferred.

  The said aspect WHEREIN: The said support part (3) is comprised from the some support member (31,32,33,34) connected by the extension direction, and the said one pressing means (4,4A) It is preferable that it is provided on any one (32) of the plurality of support members (31, 32, 33, 34).

  In the above aspect, it is preferable that the plurality of support members (31, 32, 33, 34) include those not provided with the pressing means (4, 4A).

  In the above aspect, it is preferable that one pressing means (4, 4A) has a plurality of pressing points at equal intervals in the circumferential direction.

  In the above aspect, when a plurality of the pressing means (4, 4A) are provided in the extending direction of the support portion (3), it is preferable that the pressing directions include different ones.

  Still another aspect of the present invention is a steel pipe pile construction method characterized in that a steel pipe is gripped by using any one of the above-described vibro hammer gripping devices and the steel pipe is driven or pulled out.

  A gripping device for a steel pipe in a vibratory hammer according to the present invention includes a support portion extending downward and one or a plurality of pressing means, and grips the steel pipe by applying a pressing force to only one of the inner surface and the outer surface of the steel pipe. In this case, the position where the steel pipe is pressed is an area where the steel pipe is not deformed by the pressing force. As a result, the steel pipe can be securely gripped at the time of driving or drawing, and at the same time, deformation of the steel pipe can be prevented.

  In particular, when a pressing force is applied to the inner surface of a steel pipe, there is no need to provide a force against the pressing force on the outside of the steel pipe. Effective when it cannot be secured.

  In addition, when a pressing force is applied to the inner surface of the steel pipe, a position close to the lower end of the steel pipe can be gripped by the pressing means by elongating the support portion, so that the vibration force can be effectively transmitted to that position. As a result, the steel pipe can be easily driven and pulled out.

  In addition, when pulling out a steel pipe, the inner surface of the steel pipe is gripped by pressing means at a position where there is a viscous soil with a strong adhesive force (adhesive force) with the outer surface of the steel pipe, such as a silt layer or a clay layer. The vibration force can be transmitted effectively. As a result, the steel pipe can be easily pulled out.

  Moreover, when pulling out the steel pipe, it is considered that deformation due to the pressing force does not occur at the lower end of the steel pipe having the largest earth pressure. Therefore, by grasping the inner surface of the lower end region of the steel pipe by the pressing means, the vibration force can be effectively transmitted to that position. As a result, the steel pipe can be easily pulled out.

FIG. 1 is a side view schematically showing a construction situation including an example of a first embodiment of a gripping device for a vibratory hammer according to the present invention. 2 is a schematic enlarged view of the gripping device of FIG. 1, (a) is a front view, (b) is a partially cutaway side cross-sectional view shown with a steel pipe (longitudinal cross section), and (c) (B) is the II sectional view, (d) is the II-II sectional view of (b). FIG. 3 (a) is a partially cutaway side sectional view showing an example of a second embodiment of a gripping device for a vibratory hammer according to the present invention together with a part of a steel pipe (longitudinal section), and FIG. Is a sectional view taken along line III-III. FIG. 4: is a side view which shows roughly the construction condition containing an example of 3rd Embodiment of the holding apparatus of the vibratory hammer by this invention. FIG. 5 (a) is a front view showing an example of a fourth embodiment of a gripping device for a vibratory hammer according to the present invention, and (b) shows the gripping device of (a) together with a part of a steel pipe (longitudinal section). It is a partially cutaway sectional side view, and (c) is a view showing an example of a usage pattern of the gripping device of (a). FIGS. 6 (a) and 6 (b) are partially cutaway side cross-sectional views each showing an example of another embodiment of a gripping device for a vibratory hammer according to the present invention together with a part of a steel pipe (longitudinal cross section). 7A, 7B, 7C, and 7D are cross-sectional views schematically showing modifications of the pressing means of the gripping device. FIGS. 8 (a) and 8 (b) are cross-sectional views of each stage schematically showing a modified example in which the pressing means of the gripping device is arranged in three stages. FIG. 9 is a plan view and a longitudinal sectional view schematically showing deformation characteristics of a steel pipe when a pressing force is exerted outwardly in the X direction on the inner surface, taking a cylindrical steel pipe as an example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings of the respective embodiments and modifications, the same or similar components are denoted by the same or similar reference numerals. In general, “gripping” is often used in the sense of grasping an object from both sides, but in this specification, it includes a case where a pressing force is applied to the inner surface of the tubular object and held by a tensile force. Although the gripping device of the present invention will be described based on an example in which the gripping device of the present invention is mainly applied to a cylindrical steel pipe, the gripping device of the present invention can also be applied to a square tube-shaped steel pipe.

(1) 1st Embodiment FIG. 1: is a side view which shows roughly the construction condition containing the structural example of 1st Embodiment of the holding apparatus of the vibratory hammer by this invention. 2 is a schematic enlarged view of the gripping device of FIG. 1, (a) is a front view, (b) is a partially cutaway side cross-sectional view shown with a steel pipe (longitudinal cross section), and (c) (B) is the II sectional view, (d) is the II-II sectional view of (b).

  As shown in FIG. 1, the vibratory hammer VH includes a vibrator 9 and a gripping device 1. The gripping device 1 of the present embodiment includes a head portion 2 attached to the lower surface of the vibrator 9, a columnar or tubular support portion 3 extending downward from the lower surface of the head portion 2, and the extension of the support portion 3. And pressing means 4 provided at one or a plurality of locations in the direction. In the illustrated example, the pressing means 4 is provided at three places, that is, three stages. The pressing means 4 may be one place, that is, one stage as long as a sufficient pressing force can be obtained. Moreover, although the cross-sectional shape of the support part 3 is substantially rectangular, other shapes may be sufficient as long as the pressing means 4 can be supported. The supporting part 3 may be hollow to accommodate a driving part (hydraulic hose or the like) of the pressing means 4. In 1st Embodiment, the support part 3 is arrange | positioned inside the steel pipe P, and each press means 4 can generate | occur | produce outward pressure with respect to the inner surface of the steel pipe P. As shown in FIG.

  As shown in FIGS. 2A and 2B, in the illustrated example, a plurality of reinforcing ribs are provided on the lower surface of the head portion 2 and the upper portion of the support portion 3. Further, in the illustrated example, each pressing means 4 includes a pair of claws directed in directions opposite to each other with respect to the axis of the support portion 3. As shown in the partial cross section of FIG. 2B, one of the pair of claws is a fixed claw 41 and the other is a movable claw 42. The movable claw 42 is driven forward or backward by, for example, a piston integral with the movable claw 42 moving in the cylinder portion 43 by hydraulic pressure. The hydraulic claw 42 can be hydraulically driven by a mechanism (not shown) similar to a general gripping device, and details thereof are omitted here. For the sake of explanation, FIG. 2C shows a state in which the movable claw 42 is retracted (when not pressed), and FIG. 2D shows a state where the movable claw 42 has advanced (when pressed). Specifically, the movable claws 42 of all the pressing means 4 are driven synchronously.

  A friction force is generated between the inner surface of the steel pipe P by the pressing force exerted by the three-stage pressing means 4 as a whole, and the pressing means 4 and the steel pipe P are fixed to each other. This frictional force must be large enough to prevent the steel pipe P and the pressing means 4 from shifting or coming off due to vibrations caused by the excitation force during driving or pulling. That is, the friction force must be larger than the vibration force of the vibration generator 9. This state is a state in which the steel pipe P is gripped by the gripping device 1. As a result, the excitation force transmitted to the upper end of the support portion 3 is transmitted to the steel pipe P through the pressing means 4.

  Each pressing surface 41a, 42a of the fixed claw 41 and the movable claw 42 is formed with a large number of irregularities (for example, a form in which a large number of square pyramid small protrusions are arranged vertically and horizontally) as a slip stopper in order to obtain a sufficient frictional force. It is preferred that Moreover, it is suitable that these pressing surfaces 41a and 42a are curved so as to follow the inner surface of the steel pipe P.

  On the other hand, it is necessary to prevent deformation of the steel pipe P as shown in FIG. 9 by the pressing force of the pressing means 4. For this reason, in this invention, the position of the 1 or several press means 4 on the support part 3 is set as follows (same also in each following embodiment).

  First, a pressing force necessary to grip the steel pipe P is calculated based on the vibration force of a vibrator of a vibratory hammer. Next, the pressing force borne by the first pressing means 4 is calculated according to the number of the pressing means 4. Next, based on the pressing force applied by the pressing means 4 per stage and the material mechanical properties (diameter, thickness, length, proof stress, etc.) of the steel pipe P, the steel pipe P against the pressing force. The range of the intermediate region L2 that does not cause deformation is determined. When the pressing means 4 per stage has a plurality of pressing points in the circumferential direction, “no deformation” means that no deformation is caused by the pressing force distributed to each pressing point.

  For example, as shown in FIG. 9, when a pressing force is applied to different positions in the length direction of the steel pipe P, a position where the deformation amount with respect to the diameter Φ is less than ± 0.5% is obtained. Up to that position is defined as an upper end region L1 that causes deformation. Similarly, a position from the lower end of the steel pipe to the same distance is defined as a lower end region L3 that causes deformation. A region between the upper end region L1 and the lower end region L3 is defined as an intermediate region L2 that is not deformed.

  In the present invention, in principle, the pressing means 4 is not disposed in a region where deformation is caused by a pressing force applied to only one of the inner surface and the outer surface of the steel pipe. Therefore, the position where each pressing means 4 presses the steel pipe P is basically within the range of the intermediate region L2 in the length direction of the steel pipe P. In the example of FIG. 1, the uppermost first-stage pressing means 4 is installed at the upper end position of the intermediate region L2.

  In the example shown in FIGS. 1 and 2, since the steel pipe top end is located at the upper end of the support part 3, the head part 2 is provided at the upper end of the support part 3 and the steel pipe top end is brought into contact with the lower surface thereof. Depending on the construction conditions, the top end of the steel pipe may be located below the upper end of the support part 3, in which case the head part 2 becomes unnecessary. When the top end of the steel pipe is brought into contact with the lower surface of the head portion 2, the vibration force of the vibration generator 9 is transmitted directly from the head portion 2 to the steel pipe P, which is efficient. This also reinforces the fixing strength between the two. In addition, when the top end of the steel pipe is brought into contact with the head portion 2, it is easy to accurately define the holding position of the pressing means 4.

  In the example shown in FIG. 2, the second-stage and third-stage pressing means 4 are installed at equal intervals below the first-stage pressing means 4. The number of steps of the pressing means 4 may be one, not limited to three, and may be two or four or more. Moreover, it is not necessary to install the plurality of steps of pressing means 4 at equal intervals, and the intervals between the steps can be set as appropriate. Even when the pressing means 4 is arranged at a position relatively close to the lower end side of the steel pipe by elongating the support portion 3, in principle, it is within the range of the intermediate region L2 above the lower end region L3 (described later). Excluding the third embodiment).

  As described above, the present invention is not a general idea of gripping a steel pipe at or near the top end of a steel pipe as in the conventional gripping device of a vibratory hammer, but a position away from the top of the steel pipe by a predetermined distance, This is based on a novel idea of gripping a steel pipe even at a position closer to the lower end side than the end.

(2) Second Embodiment FIG. 3A is a partially cutaway side sectional view showing an example of a second embodiment of a gripping device for a vibratory hammer according to the present invention together with a part of a steel pipe (longitudinal section). (B) is a III-III sectional view of (a).

  As shown in FIG. 3A, the gripping device 1 includes a head portion 2 attached to the lower surface of the vibrator, a tubular support portion 3 extending downward from the lower surface of the head portion 2, and the support portion 3. And pressing means 4A provided at one or a plurality of locations in the extending direction. In the second embodiment, the support portion 3 is disposed outside the steel pipe P. As shown in FIG. 3B, in the illustrated example, the cross-sectional shape of the support portion 3 is rectangular, but other shapes may be used as long as the pressing means 4A can be supported.

  In the example of FIG. 3, each pressing means 4 </ b> A can generate a pressing force inward with respect to the outer surface of the steel pipe P. Each pressing means 4 </ b> A includes a pair of claws facing each other on two opposing walls of the support portion 3, one being a fixed claw 41 and the other being a movable claw 42. The movable claw 42 is driven forward or backward by, for example, a piston integral with the movable claw 42 moving in the cylinder portion 43 by hydraulic pressure. The movable claw 42 can be driven by a mechanism (not shown) similar to that of a general gripping device, and the details are omitted here. The movable claws 42 of the pressing means 4A in all stages are driven synchronously. The number of steps of the pressing means 4A is at least one. The interval in the case of providing a plurality of stages can also be set as appropriate.

  A frictional force is generated between the outer surface of the steel pipe P by the pressing force exerted by all the pressing means 4A as a whole, and the pressing means 4A and the steel pipe P are fixed to each other. This state is a state in which the steel pipe P is gripped by the gripping device 1. It is preferable that the pressing surfaces 41a and 42a of the fixed claw 41 and the movable claw 42 are formed with a large number of irregularities as a slip stopper in order to obtain a sufficient frictional force. Moreover, it is preferable that these pressing surfaces 41a and 42a are curved so as to follow the outer surface of the steel pipe P.

(3) Third Embodiment FIG. 4 is a side view schematically showing a construction situation including an example of a third embodiment of a gripping device for a vibratory hammer according to the present invention.

  The third embodiment is a form applied when the steel pipe P is pulled out. In the vicinity of the steel pipe P, for example, it is assumed that soils with different soils exist in the order of the ground surface, gravel layer A, silt layer / clay layer B, and sand layer C. Such ground characteristics are usually known before construction. In the example of the gripping device 1 of this embodiment shown in FIG. 4, the pressing means 4 a and 4 b are provided at two places on the support portion 3.

  The first-stage pressing means 4 a is arranged at a position where the silt layer / clay layer B exists around the steel pipe P. Cohesive soil such as a silt layer or clay layer has a large adhesive force (adhesion) with the outer surface of the steel pipe. Therefore, the steel pipe P can be efficiently detached from the surrounding ground by transmitting the vibration force directly at this position.

  The second-stage pressing means 4b is disposed at the substantially lower end of the steel pipe P. When the periphery of the steel pipe P is a space, this position is in the lower end region L3 that is deformed by the pressing force. Therefore, in the above-described embodiment, the pressing means is not disposed. However, in the case of this embodiment, since the steel pipe P receives earth pressure from the surroundings, it is considered that this becomes a counter force and deformation due to the pressing force of the pressing means 4b does not occur. As for the upper end region L1, it is desirable not to provide the pressing means for the upper end region L1 as in the above-described embodiment because there is no earth pressure acting as a counter force immediately after the start of drawing. Therefore, in this embodiment, as long as it exists in the range of the area | region L4 to the lower end except the intermediate | middle area | region L2 and lower end area | region L3 of the steel pipe P, ie, upper end area | region L1, you may provide a press means. And since the lower end of the steel pipe P is the position where the earth pressure is the largest, the steel pipe P can be efficiently detached by transmitting the vibration force directly at this position.

  In the gripping device for a vibratory hammer, as in the present invention, the structure for gripping the intermediate region and the lower end region of the steel pipe and transmitting the vibration force directly to the intermediate region and the lower end region of the steel pipe is a conventional general gripping method. This is a completely different method.

(4) Fourth Embodiment FIG. 5 (a) is a front view showing an example of a fourth embodiment of a gripping device for a vibratory hammer according to the present invention, and FIG. 5 (b) shows a gripping device of FIG. It is a partial notch side sectional view shown with a part of (longitudinal section), and (c) is a partially notched side sectional view showing an example of a usage form of the gripping device of (a).

  As shown in FIGS. 5 (a) and 5 (b), in the fourth embodiment, the support unit 3 of the gripping device 1 of the first embodiment described above has a plurality of support members 31, 32 connected in the axial direction. It is composed of The uppermost support member 31 is joined to the lower surface of the head portion 2 and includes a plurality of reinforcing ribs on the upper portion. A flange 31 a is formed at the lower end of the support member 31. Another support member 32 has flanges 32a at the upper and lower ends of a columnar or tubular main body. The support member 31 and the support member 32 are brought into contact with each other by bringing the flanges 31a and 32a into contact with each other, and the support members 32 are brought into contact with each other with the flanges 32a and 32a coming into contact with each other and appropriately fixed with a fixing tool such as a bolt or nut. . In the example of FIGS. 5A and 5B, the pressing means 4 is provided on each of the three continuous support members 32.

  Although not shown, the fourth embodiment can also be applied to the support portion 3 of the gripping device 1 of the second embodiment and the third embodiment.

  In the example of the usage pattern in FIG. 5C, the support member 33 that does not include the pressing unit 4 is inserted between the support member 31 and the support member 32 and between the support members 32. The support member 33 is also formed with flanges 33a at the upper and lower ends, and can be connected in the axial direction. The support member 33 serves as a spacer for installing the pressing means 4 included in the support member 32 at an appropriate position. If necessary, a plurality of support members 33 may be connected continuously. For example, when it is desired to install and hold the pressing means 4 at a position close to the lower end of the steel pipe P, a relatively long support member 33 may be connected, or a necessary number of support members 33 may be connected.

(4) Other Embodiments Hereinafter, other embodiments of the gripping device according to the present invention will be described. As long as possible, these embodiments may be applied in combination with the features of each other, or may be applied in combination with the features of the above-described embodiments.

  FIGS. 6 (a) and 6 (b) are partially cutaway side cross-sectional views each showing an example of another embodiment of a gripping device for a vibratory hammer according to the present invention together with a part of a steel pipe (longitudinal cross section). This embodiment is a form in which there is no head portion in the gripping device of the above-described embodiment.

  In the example of FIG. 6A, the top end of the steel pipe P is at a position away from the upper end of the support portion 3. For example, when the steel pipe P is driven or pulled out from the bottom of the water bottom, the top end of the steel pipe is below the water surface, but the upper end of the support portion 3 needs to be located above the water. Also in this case, a spacer-like support member 33 having an appropriate length is interposed so that the pressing means 4 holds the steel pipe P in the intermediate region (including the lower end region in the case of the third embodiment described above). Yes. The holding position of the pressing means 4 is determined by measuring the position of the steel pipe top end in advance.

  In the example of FIG. 6 (b), the top end of the steel pipe P is located at a position away from the upper end of the support portion 3 as in the example of (a), but a flange 34a for pressing the top end of the steel pipe P is provided. A support member 34 is inserted. Since the flange 34a has a larger diameter than the diameter of the steel pipe P, it can be pressed against the top end of the steel pipe P. In this example, the vibration force can be directly transmitted to the steel pipe P, and the fixing strength of the steel pipe P can be reinforced. Further, it is easy to accurately define the grip position of the pressing means 4.

  FIGS. 7A, 7B, 7C, and 7D are cross-sectional views schematically showing modifications of the pressing means of the gripping device 1. FIG. One (one step) pressing means in the present invention has two or more pressing points. In that case, these pressing points exert a uniform pressing force on the inner surface or outer surface of the steel pipe P as a whole. Is arranged.

  In FIG. 7A, two pairs of fixed claws 41 and movable claws 42 opposite to each other are arranged in a cross shape. In FIG. 7B, one fixed claw 41 and two movable claws 42 are arranged at intervals of 120 degrees. FIG. 7C is an example of all movable claws, and six movable claws 42 are arranged at intervals of 60 degrees. FIG. 7D shows an example in the case of a square tubular steel pipe P. In the case of pressing the inner surface, the arrangement is not limited to these examples as long as the necessary tension force can be loaded. Although not shown, even when a pressing force is applied to the outer surface, various arrangements of the fixed claw and the movable claw are possible.

  FIGS. 8A and 8B are cross-sectional views of each stage schematically showing a modification example in which the pressing means of the gripping device 1 is arranged in three stages. In FIG. 8A, the pressing directions by the first and third stage fixed claws and the movable claw are the same, and the second stage pressing direction is perpendicular thereto. In FIG. 8B, the pressing directions of the fixed claw and the movable claw at each stage form an angle of 120 degrees. In the case of having a plurality of steps of pressing means, the pressing directions may be different from each other. In that case, it is preferable to set the direction of pressing in a balanced manner as a whole.

DESCRIPTION OF SYMBOLS 1 Gripping device 2 Head part 3 Support part 31, 32, 33, 34 Support member 4, 4A, 4a, 4b Pressing means 41 Fixed claw 42 Movable claw 43 Cylinder part 9 Exciter VH Vibro hammer P Steel pipe

Claims (9)

A gripping device (1) for a vibratory hammer (VH) for gripping a steel pipe (P),
A support portion (3) that transmits the vibration force of the vibrator hammer (VH) to the upper end and extends downward;
One or a plurality of pressing means (4) provided at one or a plurality of locations in the extending direction of the support portion (3) and capable of generating a pressing force outward with respect to the inner surface of the steel pipe (P). And
The pressing force by the one or more pressing means (4) has a magnitude that generates a frictional force capable of gripping the steel pipe (P) when driven or pulled by the vibratory hammer (VH), and the one or more Each of the pressing means (4) presses the steel pipe (P) in the length direction of the steel pipe (P) when there is no resistance force against the pressing force. A vibratory hammer gripping device, which is located in an intermediate region (L2) excluding an upper end region (L1) and a lower end region (L3) that cause deformation . A gripping device (1) for a vibratory hammer (VH) for gripping a steel pipe (P),
A support portion (3) that transmits the vibration force of the vibrator hammer (VH) to the upper end and extends downward;
One or a plurality of pressing means (4) provided at one or a plurality of locations in the extending direction of the support portion (3) and capable of generating a pressing force inward with respect to the outer surface of the steel pipe (P). And
The pressing force by the one or more pressing means (4) has a magnitude that generates a frictional force capable of gripping the steel pipe (P) when driven or pulled by the vibratory hammer (VH), and the one or more Each of the pressing means (4) presses the steel pipe (P) in the length direction of the steel pipe (P) when there is no resistance force against the pressing force. A vibratory hammer gripping device, which is located in an intermediate region (L2) excluding an upper end region (L1) and a lower end region (L3) that cause deformation . A gripping device (1) for a vibratory hammer (VH) for gripping a steel pipe (P),
A support portion (3) that transmits the vibration force of the vibrator hammer (VH) to the upper end and extends downward;
One or a plurality of pressing means (4) provided at one or a plurality of locations in the extending direction of the support portion (3) and capable of generating a pressing force outward with respect to the inner surface of the steel pipe (P). And
The pressing force by the one or more pressing means (4) has a magnitude that generates a frictional force capable of gripping the steel pipe (P) when being pulled out by the vibratory hammer (VH), and the one or more pressing means Each of the means (4) presses the steel pipe (P) in the length direction of the steel pipe (P), when there is no resistance against the pressing force , the pressing force causes plastic deformation of a predetermined amount or more. There occurring upper end region (L1) and the region excluding the upper end region (L1) of the lower end region (L3) (L2, L3), and at least one of the pushing pressure position to the lower end region (L3) A vibratory hammer gripping device.   The pressing means (4, 4A) is a combination of one or a plurality of fixed claws (41) and one or a plurality of movable claws (42), or a plurality of movable claws (42). The vibro hammer gripping device according to any one of claims 1 to 3.   The support part (3) is composed of a plurality of support members (31, 32, 33, 34) connected in the extending direction, and one pressing means (4, 4A) The vibratory hammer gripping device according to claim 4, wherein the gripping device is provided on any one of the support members (31, 32, 33, 34).   The gripping device for a vibratory hammer according to claim 5, wherein the plurality of support members (31, 32, 33, 34) include those not provided with the pressing means (4, 4A).   The gripping device for a vibratory hammer according to any one of claims 4 to 6, wherein one pressing means (4, 4A) has a plurality of pressing points at equal intervals in the circumferential direction.   When a plurality of the pressing means (4, 4A) are provided in the extending direction of the support portion (3), the pressing directions include those that are different from each other. A gripping device for a vibratory hammer according to claim 1.   The construction method of the steel pipe pile characterized by holding a steel pipe using the holding apparatus of the vibro hammer in any one of Claims 1-8, and driving or drawing | extracting this steel pipe.

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