JP2007120283A - Anchor maintenance jack and jack-up method of existing ground anchor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anchor maintenance jack which is compact and has a small number of components, and which can be maintained easily and safely. <P>SOLUTION: The anchor maintenance jack, which raises the excessive length H of the existing ground anchor and measures ground-fixing ability, is provided with a cylinder rod 1 and a guide tube 2. The cylinder rod 1 has an interior diameter which is larger than or equal to the outer diameter of the excessive length H, and the guide tube 2 guides the stroke of the cylinder rod 1 in the circumference of the cylinder rod 1. Then an inner screw structure 12, which is screwed to the outer screw on the outer periphery of the excessive length H, is provided so that it overlaps the substantial stroke part Els of the cylinder rod 1 in the stroke direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an anchor maintenance jack that performs maintenance by pulling up an extra length portion H of an existing ground anchor.

  Conventionally, there is a center hole jack as a jack attached to a ground anchor (see, for example, Patent Document 1).

    However, since the conventional center hole jack has a jack mechanism disposed at the tip side of the surplus portion H, a sufficient stroke amount and a stable jack force can be secured, while an extension rod or the like that extends the surplus portion H is provided. Due to the fixing mechanism etc. to the jack tip, the volume or the weight of the parts is increased, and it cannot be said that it is compact. In particular, when performing maintenance of an existing ground anchor, there is no scaffold as in the case of ground anchor fixing construction, so it is difficult to attach a high-torque jack-up device mechanism to the extra length H protruding on the slope at a high place. For this reason, it has been difficult to perform safe and easy maintenance work with the conventional center hole jack.

    In addition, as a conventional anchor maintenance jack, there is an anchor fixing portion in which the lower end side of the cylinder rod 1 is extended toward the bearing plate P, and the extra length portion H is fixed by this anchor fixing portion. This is because the extra long portion H is surrounded by an inner cylindrical anchor fixing portion which is slightly larger than the extra length portion H, and a wedge-shaped fixture is sandwiched between the lower end of the anchor fixing portion and the extra length portion H. A fixed state is formed (see, for example, Patent Document 2).

However, fixing with such a wedge-shaped fixture is insufficient as a fixing means for a ground anchor to which a tensile load of several tens of tons per one is applied. It could not be said that maintenance was possible. In addition, the attachment by sandwiching a plurality of wedge-shaped fixtures is complicated, and the weight increases due to the attachment structure or the like, so that it cannot be said that maintenance is easy.
JP 2004-294235 A Japanese Utility Model Publication No. 64-28431

  Accordingly, an object of the present invention is to provide an anchor maintenance jack that is compact and does not have a large volume or weight and can be maintained easily and safely.

In order to solve the above problems, the present invention takes the following means (1) to (7). That is,
(1) The anchor maintenance jack of the present invention is an anchor maintenance jack that can measure the ground fixing property by jacking up the extra length H (anchor head) provided with external screws on the ground surface side of the existing ground anchor. An internal screw structure that engages with an external screw on the outer periphery of the extra length H, a cylinder rod 1 that pulls up the internal screw structure by a stroke toward the ground surface in the axial direction of the ground anchor, and a cylinder around the cylinder rod 1. And a guide tube 2 for guiding the stroke of the rod 1, wherein the internal screw structure is provided at an axial height that overlaps at least a part of the substantial stroke portion Els of the cylinder rod 1. To do.

  If it is such, the fixing means to the surplus length part H is screwed fixation, and the substantial stroke part Els of the cylinder rod 1 is directly screwed on the outer periphery of the surplus length part H, and the surplus length part H Can be fixed in a state of covering directly from the side periphery. For this reason, a sufficient fixing force can be ensured with certainty, and an extension rod for extending the surplus length H is not required, thereby achieving weight reduction and volume reduction. Further, in the attached state, it is possible to suppress the height in the stroke direction (distance from the bearing plate P), in particular, the portion that protrudes further forward than the surplus length portion H, and it becomes more compact.

  The cylinder rod 1 has a through hole 11 having an inner diameter equal to or larger than the outer diameter of the surplus length portion H through which the surplus length portion H can pass, and an internal screw structure is provided from the lower end of the through hole 11 or in the vicinity thereof. .

  (2) The anchor maintenance jack includes inner screw structures 1a, 1b, 1c,... That can be accommodated inside the cylinder rod 1, and the inner screw structures 1a, 1b, 1c,. However, it is preferable to include the through-hole 11 through which the extra length portion H can penetrate and the inner screw structure directed upward from the lower end of the through-hole. That is, the through hole 11 has an inner diameter through which the extra length portion H can pass, and is open to the upper and lower ends inside the cylinder rod 1. Further, the inner screw structure is provided from the lower end of the through hole 11 toward the surface in the axial direction (upward). As long as the inner screw structure 12 is provided at least from the lower end of the through hole 11, the inner screw structure 12 may extend to less than the vicinity of the center of the through hole 11, or to the vicinity of the center of the through hole 11, or from the lower end of the through hole 11. It may extend to the upper end, that is, the entire length of the through hole 11.

  If it is such, the surplus length part H screwed in the cylinder rod 1 from the cylinder rod 1 lower end can protrude from the cylinder rod 1 upper end. For this reason, even if the surplus length portion H screwed reaches the upper end of the cylinder rod 1, it can be further tightened, and regardless of the total length or stroke length ls of the cylinder rod 1, the lifting height of the surplus length portion H, that is, the ground The lifting length of the anchor can be secured. Thereby, for example, the full length, stroke length ls, or screwing length of the cylinder rod 1 can be made shorter than the extra length H length, and it becomes extremely compact.

  In addition, by pulling up the ground anchor with a relatively large lifting length, it is possible to reliably identify the presence or absence of the primary bending point relative to the anchor fixing force lifting length, and to further increase the lifting length after the primary bending point. When recommended, the anchor fixing force behavior (that is, anchor fixing force-lifting length data) can be easily recognized.

  In addition, anchor fixing increases as the pull-up length increases. As the screwing length increases, the contact area of the surplus portion H with the inner surface of the cylinder rod 1 increases, so that the fixing force to the surplus length portion H is always secured. It is possible to prevent accidents caused by poor installation.

  (3) Further, in any one of the anchor maintenance jacks, a plurality of internal screw structures 1a, 1b, 1c,... Having different inner diameters are provided in the cylinder rod 1 so as to be exchangeable. It is preferable.

  The inner screw structures 1a, 1b, 1c,... Are made of a cylindrical body having an insertion hole inside. Specifically, the cylindrical body has an outer shape that can be inserted through the inner hole of the cylinder rod 1 and an inner shape that includes an insertion hole through which the extra length portion H of the ground anchor can be inserted. The insertion hole of this cylindrical body penetrates from the upper end to the lower end, starts from at least the lower end of the insertion hole, and is provided with an internal screw structure that extends upward, that is, toward the surface in the axial direction.

  The internal screw structures 1a, 1b, 1c,... Of Example 3 are accommodated in the cylinder rod 1 with a predetermined clearance, and the cylindrical outer surfaces of the internal screw structures 1a, 1b, 1c,. By sliding inside the cylinder rod 1, it is accommodated so as to be freely rotatable.

  Further, the cylinder rod 1 includes a plurality of first, second, third,... Inner screw structures 1a, 1b, 1c,. The plurality of internal screw structures 1a, 1b, 1c,... Can be replaced in a so-called attachment type, and correspond to various ground anchors having different extra length H diameters. I can do it.

  (4) In any one of the anchor maintenance jacks, the inner screw structures 1a, 1b, 1c... Are fitted to the cylinder rod 1 at the upper end, and the cylinder rod 1 is inserted into the cylinder rod 1. It is preferable that it is accommodated so as to be freely rotatable (pivotable). The cylinder rod 1 can be freely rotated (including free rotation in either direction). For example, the inner screw structures 1a, 1b, 1c,. This is possible by providing a predetermined clearance.

  If this is the case, it is possible to perform additional tightening to the extra length portion H of the internal screw structure without removing the connection to the guide tube 2 such as the hydraulic hose 33, and the anchor maintenance work is easier. It becomes.

  (5) In any one of the anchor maintenance jacks, the anchor maintenance jack includes a leg unit that stands on the bearing plate P and supports the cylinder rod 1 and the guide tube 2, and a plurality of strain gauges 27 are connected to the leg It is preferable that the unit is disposed so as to be symmetrical with respect to the anchor axis of the ground anchor. If it is such, the tensile force can be measured with higher accuracy by measuring the amount of strain based on the load on the leg portion 24 or the leg-to-leg bridge 26 when jacking up.

  (6) Further, in any one of the anchor maintenance jacks, the cylinder rod is erected on the bearing plate P and fitted with the lower end of the guide tube 2 or the outer cover covering the guide tube 2 at the upper end with the conical surface. 1 and a leg unit for supporting the guide tube 2 are preferably provided. The leg unit includes a leg 24 and an inter-leg bridge 26.

  (7) Moreover, the jack-up method for the existing ground anchor of the present invention includes an internal screw structure that can be screwed into the extra length portion H of the existing ground anchor fastened by the bearing plate P, and an axial direction of the ground anchor. Using an anchor maintenance jack comprising a cylinder rod 1 that can be stroked up / down along the same, and a leg portion 24 that supports the inner screw structure and the cylinder rod 1 and stands on the bearing plate P, This is a jackup method for an existing ground anchor in which the extra length H provided with an external thread of the ground anchor is jacked up by the stroke of the cylinder rod 1.

Then, anchor maintenance is performed by directly screwing the inner screw structure into the outer screw of the extra length portion H (on the ground surface side of the ring nut N) where the ring nut N is screwed (to the outer screw of the extra length portion H). Screw the jack to the extra length H,
This extra length H is jacked up with the ring nut N by increasing the stroke of the cylinder rod 1,
The ring nut N screwed into the jacked-up extra length H is tightened and brought into contact with the bearing plate P,
The cylinder rod 1 is stroked down, and the cylinder rod 1 and the guide tube 2 are lifted to the raised extra length side.
The inner screw structure is tightened and the leg portion 24 is brought into contact with the support plate P integrally with the guide tube 2,
The extra length portion H jacked up is further jacked up (together with the ring nut N) by the stroke up of the cylinder rod 1.

  Furthermore, this existing ground anchor jack-up method is a jack-up method of jacking up using any one of the anchor maintenance jacks described in (1) to (6) above or an anchor maintenance jack combining a part of the construction. It is preferable.

  The anchor maintenance jack of the present invention has the above-described configuration, is compact and does not have a large volume or weight, and can perform anchor maintenance easily and safely.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings illustrating the embodiments. 1 to 8 show an anchor maintenance jack according to a first embodiment of the present invention, and FIGS. 9 to 11 show an anchor maintenance jack according to a second embodiment of the present invention. 12, 13 and 14 show an anchor maintenance jack according to a third embodiment of the present invention. 15 and 16 show an example of the extra length portion H of the ground anchor to which the anchor maintenance jack of the present invention is attached. FIG. 17 and FIG. 18 show the comparison test results of load-displacement between the anchor maintenance jack of the present invention and the center hole jack by jacking up an existing ground anchor.

(Anchor maintenance jack of the present invention)
The anchor maintenance jack of the present invention is an anchor maintenance jack for measuring the ground fixing property by pulling up the extra length portion H provided with an external screw on the outer periphery in advance. The cylinder rod 1 has an inner diameter equal to or larger than the outer diameter of the extra length H, and a guide tube 2 that guides the stroke of the cylinder rod 1 around the cylinder rod 1. Further, as the fixing means to the surplus length portion H, a reliable screwing and fixing by an internal screw structure 12 that is screwed to an external screw on the outer periphery of the surplus length portion H is adopted, and this internal screw structure 12 is arranged in the stroke direction. The cylinder rod 1 is provided so as to overlap with at least a part of the substantial stroke portion Els of the cylinder rod 1.

(The existing ground anchor jack-up method of the present invention)
Moreover, the existing ground anchor jack-up method of the present invention jacks up the extra length portion H provided with the external thread of the ground anchor by the stroke of the cylinder rod 1 using an anchor maintenance jack. And it is characterized by comprising the following processes (a) to (f).

  The jack for anchor maintenance used in this jack-up method has an internal screw structure that can be screwed to at least an extra length H of an existing ground anchor fastened by a bearing plate P, and a stroke up along the axial direction of the ground anchor. / The cylinder rod 1 that can be stroked down, and the leg portion 24 that supports the internal screw structure and the cylinder rod 1 and stands on the bearing plate P are provided.

  (A) The inner screw structure is directly screwed into the outer screw of the extra length H, and the anchor maintenance jack is screwed and fixed to the extra length H. This is the anchor maintenance jack attachment process. The extra length H at this time is a ring nut N screwed state in which the ring nut N is screwed to the external screw.

  However, before the anchor maintenance jack is screwed and fixed, the ring nut N is externally screwed to the extra length H where there is no ring nut N in the existing state, such as a ground anchor using a wedge type fixing tool. The ring nut N threading process to be threaded is passed through.

  (B) Next to the anchor maintenance jack mounting step, the extra length portion H is jacked up together with the ring nut N by the stroke up of the cylinder rod 1. This is the jack-up process. At this time, the ring nut N screwed to the surplus length portion H is pulled up together with the surplus length portion H, and the lower surface of the ring nut N is separated from the bearing plate P.

  (C) The ring nut N screwed into the extra length H jacked up through the jack-up process is tightened further downward in the axial direction, that is, to the base of the extra length H (support pressure plate P). Abut against P. This is the ring nut N retightening step.

  (D) After the ring nut N retightening step, the cylinder rod 1 is stroked down by reducing the hydraulic pressure of the hydraulic mechanism, and the cylinder rod 1 and the guide tube 2 are floated on the raised extra length side. This is a stroke down process.

  (E) Next to the stroke down step, the inner screw structure is tightened to bring the leg portion 24 into contact with the bearing plate P integrally with the cylinder rod 1 and the guide tube 2. Here, the term “integral” means that the separable leg unit and the structure composed of the cylinder rod 1 and the guide tube 2 are combined and the leg 24 supports the cylinder rod 1 and the guide tube 2. It means that it is in a state. This is the inner screw structure retightening step.

  (F) After the inner screw structure retightening step, the extra length portion H that has been jacked up is further jacked up (together with the ring nut N) by the stroke up of the cylinder rod 1. This is the same as the jack-up process.

  (G) Subsequently, the ring nut N retightening step, the stroke down step, and the internal screw structure retightening step are repeated in the same order and an arbitrary number of times. As a result, jackup exceeding the stroke length ls is continuously performed.

(Ground anchor to be installed)
The ground anchor to which the anchor maintenance jack of the present invention is attached is an existing ground anchor that has passed through a fixing test during construction on the ground. This ground anchor has a configuration using a nut type fixing device (ring nut N) as shown in FIG. 15 and a configuration using a wedge type fixing device as shown in FIG. The surplus length portion H referred to in the present invention is a concept included in both of the above-described configurations, and refers to what is described below in the ground anchor of each type of fixing device.

  In the configuration using the nut type fixing tool (ring nut N) (FIG. 15), the uncurtain dong is connected to the fixing portion and free length portion in the ground, and protrudes from the support plate P at the tip to the ground surface. The bolt-shaped part of the head that appears on the front side is fastened on the bearing plate P by screwing a ring nut N that is a nut-type fixing tool. The bolt-shaped part of the head of the an curtain head is the extra length H in the present invention. The extra length H (that is, the extra length H on the ground surface side from the support plate P of the uncurtain don) is provided with an external screw, and the ring nut N is screwed there.

  However, this extra nut H referred to in the present invention does not include this ring nut N. That is, a tension of several tons to several tens of tons is applied to the uncurtain dong fixed in the ground, and in this state, the ring nut N is screwed to the extra length H, and the ring nut N is connected to the bearing plate P. By the pressure contact, the uncurtain dong is fixed in the ground in a tension state.

  In the configuration using the wedge-type fixing tool (FIG. 16), the wire-shaped tip portion of the uncurtain dong that is connected to the fixing portion and the free length portion in the ground and protrudes to the ground surface at the tip is a wedge-type fixing. It is fastened by the tool K and a trapezoidal fixing tool (H) that serves as a table into which the wedge-shaped fixing tool K is driven (FIG. 16). The table-type fixing device is provided with an external screw for use during loading (ie, tension) or unloading. The trapezoidal fixing device provided with the external screw is the extra length H in the present invention. The table-shaped fixing tool as the extra length H has a fixing hole through which the uncurtain dong is inserted, and is placed on the upper surface (surface on the ground surface side) of the bearing plate P. And the uncurtain dong fixed in the ground is passed through the fixing hole of the trapezoidal fixing tool which is the extra length H on the surface side of the bearing plate P, and a tension of several tons to tens of tons is applied. It is done. In this state, when the wedge-type fixing tool K is driven into the fixing hole, the uncurtain don W and the wedge-type fixing tool K, and the wedge-type fixing tool K and the trapezoidal fixing tool (the extra length portion H) come into contact with each other. Fixed. As a result, the wedge-shaped fixing tool K is in pressure contact with the trapezoidal fixing tool (the surplus length portion H) through the fixing hole, and the lower surface side of the trapezoidal fixing tool (the surplus length portion H) is in pressure contact with the bearing plate P. , Uncurtain Don is fixed in the ground in tension. In the configuration using the wedge type fixing tool, a ring nut that is screwed into the trapezoidal fixing tool (the extra length portion H) after the construction is not attached. For this reason, in order to hold | maintain a jack-up state safely, it is preferable to perform beforehand the ring nut N attachment process which attaches the ring nut N before attaching the anchor maintenance jack of this invention.

  The anchor maintenance jack of the present invention is screwed and fixed to the surplus length portion H to raise the surplus length portion H. As long as it has a configuration corresponding to the surplus length portion H provided with an external screw, The ground anchor (FIG. 15) using a fixing tool and the ground anchor (FIG. 16) using a wedge type fixing tool can be used.

  1 and 2 are respectively a perspective explanatory view and a plan view explanatory view of an anchor maintenance jack according to a first embodiment of the present invention. FIGS. 3 to 8 are cross-sectional explanatory views taken along the line AA of FIG. 2, and illustrate the front view state at each stage as an example of use of the anchor maintenance jack of the first embodiment. Hereinafter, each configuration of Example 1 will be described in detail.

(Cylinder rod 1)
The cylinder rod 1 has a through hole 11 that is open at both the upper and lower ends, and an inner screw is provided in the through hole 11 from the lower end to the upper end. Specifically, the cylinder rod 1 has a substantially cylindrical inner screw structure 1a, 1b, 1c,... Having the through-holes 11 and the periphery of the inner screw structures 1a, 1b, 1c,. The substantially cylindrical outer cylinder 10 that covers the cylinder is configured to be able to be held and fixed.

  Each of the inner screw structures 1a, 1b, 1c,... Has a through hole 11, and has an inner screw structure 12 at least at a substantial stroke portion Els of the through hole 11. Each of the plurality of inner screw structures 1a, 1b, 1c,... Has a substantially cylindrical shape that is screwed into the inside of the cylinder exterior 10, and has a common outer diameter and an inner diameter (through hole 11 and inner screw). Only the inner diameter of the structure 12 is different. In order to correspond to the outer diameters of various types of extra length portions H, the inner diameters are different from each other. The different inner diameters are several types according to the outer diameter type of the extra length portion H to be screwed into the inner screw structure 12.

  In the first embodiment, the first screwing structure 1a, the second screwing structure 1b, and the third screwing structure 1c are arranged in order of increasing inner diameter, and any one of these three is installed. The extra length portion H is appropriately selected according to the outer diameter, and is screwed into the inner hole of the cylinder outside 10 so as to be exchangeable.

  The cylinder exterior 10 and any one of the first inner screw structure 1a, the second inner screw structure 1b, and the third inner screw structure 1c are fixed by fixing means provided above the side portion. Specifically, the fixing means includes a fixing screw 14a and a fixing hole 14b into which the fixing screw 14a is screwed. The fixing hole 14b is formed in a protruding portion above the side portion of the cylindrical cylinder exterior 10 so as to be directed toward the center. The fixing screw 14 screwed into the fixing hole 14b has an outer screw portion of one of the first, second, third,... Screwed structures (1a, 1b, 1c...) At the tip. Both are fixed by pressing.

  In FIG. 1 to FIG. 8, the third screwing structure 1 c having the largest inner diameter (the diameter of the through hole 11) is selected from the three screwing structures and is combined with the cylinder exterior 10. In addition, as in Example 2 described later, the inner diameter may be adjusted by combining any or all of a plurality of screwed structures. (In Example 2 (FIGS. 9 to 11), as will be described later, there are a plurality of screwed structures such as a first screwed structure 1a, a second screwed structure 1b, and a third screwed structure 1c. The inner diameter (the diameter of the through hole 11) can be variably adjusted depending on the number of combinations.

(Through hole 11)
The through hole 11 is a circular hole extending from the lower end to the upper end of the cylinder rod 1 and is open to both the upper and lower ends. The inner diameter is the same as or slightly larger than the outer diameter of the extra length portion H. Of the inner surface of the through hole 11, an internal screw structure 12 is provided at an axial position (that is, an axial height) that overlaps at least the substantial stroke portion Els.

(Substantially stroke part Els of cylinder rod 1)
Here, the substantial stroke portion Els referred to in the present invention refers to the direction from the lower end of the lower pressing portion 23 of the guide tube 2 when the cylinder rod 1 is not pressurized, that is, in the lower end stroke state S1. It means a section up to one stroke length ls protruding downward. The phrase “the inner screw structure 12 is substantially at the stroke portion Els” means that the inner screw structure 12 is provided in the projecting portion below this. This section is located above the lower end of the lower holding portion 23 of the guide tube 2 in the upper end stroke state S2, and a part of the section overlaps with the height direction of the hydraulic chamber 31 that appears by pressurization. .

  Specifically, the substantial stroke portion Els in the cylinder rod 1 is below the lower end of the side protrusion 13 in the through hole 11 formed to penetrate in the vertical direction, and the lower end of the side protrusion 13. From the base end, the lower presser part thickness 23t (here, the lower presser part thickness 23t means the thickness of the lower presser part 23 in the height direction) is defined as the base end, and the lower end from the base end. In addition, this is a section extending to the stroke length ls.

  The significance of providing the internal screw structure 12 in at least a part of the substantial stroke portion Els is that it is possible to perform work on site safely and reliably while making the jack compact. Furthermore, if the inner screw is cut from the lower end of the rod 1, an anchor that has a particularly short extra length H and a long screwing section, a jack for maintenance of a ground anchor in which the strength of the screw is reduced by rust, etc. The effect suitable for up is demonstrated.

(Inner screw structure 12)
The inner screw structure 12 is provided in a part or all of the through hole 11 provided in the center of the cylinder rod 1 and through which the extra length H can pass. In the first embodiment, the through hole 11 is provided from the lower end to the upper end. However, as in the third embodiment (FIGS. 13 and 14) described later, the inner screw structure is formed from the lower end of the through hole 11 or the vicinity thereof. For example, it may be provided as long as it is provided at least from the vicinity of the lower end of the through-hole 11 toward the surface in the axial direction (upward).

(Cylinder exterior 10, side protrusion 13)
On the outside of the cylinder rod 1, a substantially cylindrical cylinder exterior 10 having substantially the same height as the inner screw structures 1 a, 1 b, 1 c,... Screwed to the outer periphery of the inner screw structure 12 is formed. Of the outer surface of the cylinder exterior 10, a side projecting portion 13 projecting in a disk shape outward is provided near the center in the height direction and slightly below. This lateral protrusion 13 is guided by the guide tube 2. Further, an inner hole is provided in the cylinder exterior 10, and the inner screw structures 1a, 1b, 1c,... Are accommodated in the inner hole, and the accommodated inner screw structures 1a, 1b, 1c,. The cylinder is fixed inside the cylinder 10 by a predetermined fixing means.

(Guide tube 2)
The guide tube 2 mainly includes a side peripheral covering portion 21 that covers the outer periphery in plan view of the side protrusion 13 of the cylinder rod 1, and an upper and lower side of the side protrusion 13 at the upper and lower ends of the side peripheral cover 21. The upper presser portion 22 and the lower presser portion 23 that respectively cover the upper and lower presser portions 23, and a leg unit that extends further downward from the lower end of the side peripheral cover portion 21. In the embodiment, the side peripheral covering portion 21, the upper pressing portion 22, and the lower pressing portion 23 are integrally configured as a guide tube body, and the leg unit that can be separated from the guide tube body has a predetermined fitting surface. And is arranged below the guide tube 2. The guide tube 2 may be provided with an external cover including a thin cylindrical plate covering the outer peripheral surface thereof. The fitting surface of the first embodiment is a horizontal fitting surface that is horizontal with the surface of the bearing plate P, and the guide tube body and the leg unit are so-called horizontally fitted.

(Leg unit)
The leg unit includes at least a plurality of leg parts 24, and preferably a plurality of leg parts 24 arranged at equal intervals, and an inter-leg bridge 26 that connects adjacent leg parts 24 to each other above each other. It is comprised integrally with. The leg 24 supports the inner screw structure and the cylinder rod 1 and stands on the bearing plate P. The lower end of the leg portion 24 is an abutment leg surface 24b that abuts against the pressure bearing plate P.

  The leg portion 24 is provided with an operation window 25 for operating the ring nut N in the attached state. The operation window 25 according to the first embodiment includes a space between the adjacent leg portions 24 opened downward, and the periphery of the operation window 25 has a pair of side surfaces opposed to each other and the leg portions 24. It is comprised by the lower surface of the bridge 26 between legs which connects.

(Strain gauge 27)
A plurality of strain gauges 27 are disposed and attached to the leg unit, that is, the leg part 24 or the leg bridge 26 so as to be in a symmetrical position in plan view with respect to the anchor axis of the ground anchor. This is to measure the pulling force at the time of jacking up by measuring the strain due to the elastic deformation of the leg unit when the pulling force of the ground anchor is applied by jacking up. The number of strain gauges 27 is preferably an even number for bridge wiring. In the first embodiment, four strain gauges 27 are provided on the outer surface of the inter-leg bridge 2627 and at the center position between the leg portions 24. When the strain gauge 27 is provided on the outer surface in this manner, it is preferable to guard the outside of the strain gauge 27 with a covering plate along the outer periphery.

(Hydraulic mechanism 3)
The hydraulic mechanism 3 includes a hydraulic chamber 31, a hydraulic connection port 32, a hydraulic hose 33 connected to the hydraulic connection port 32, and a pressure pump (not shown) that feeds pressure oil into the hydraulic hose 33. The The hydraulic chamber 31 is configured to be surrounded by the side periphery covering portion 21 of the guide tube 2, the lower pressing portion 23, the cylinder exterior 10 of the cylinder rod 1, and the side protrusion 13. In the “lower end stroke state S1” before pressurization, the lower surface of the side protrusion 13 is in contact with the upper surface of the lower presser 23 (FIG. 3), and the volume of the hydraulic chamber 31 is extremely small. After the pressurization, the pressurized oil is fed from the hydraulic connection port 32, so that the lower surface of the side protrusion 13 is pushed upward by the hydraulic pressure to become a hydraulic chamber 31 having a volume corresponding to the cylinder amount of the cylinder rod 1. 4 "upper end stroke state S2". Since the height of the hydraulic chamber 31 is common to the stroke amount, the maximum hydraulic chamber height is the stroke length ls which is the maximum stroke amount, and this time is the upper end stroke state S2.

(Side handle 4)
The side handle 4 has a grip portion in the same direction as the height direction on the peripheral side surface of the guide tube 2 or the outer side surface of the outer cover that covers the outer peripheral surface of the guide tube 2, and a plurality of side handles 4 are fixed at equal intervals. Is done. In the first embodiment, four substantially U-shaped handles bent at two upper and lower portions are provided. The side handle 4 holds the anchor maintenance jack of the present invention and fixes it to the extra length H, and adjusts the attachment angle. For example, as shown in FIG. 1, the side handle 4 is provided with four flat U-shaped grip bars extending in the vertical direction along the anchor shaft.

(Upper handle 5)
A plurality of upper handles 5 are provided on the upper surface of the cylinder rod 1. Since it is fixed to the upper surface of the cylinder rod 1 itself, the cylinder rod 1 can be reliably rotated. Further, in the lower end stroke state S1 where the hydraulic pressure is released, it is possible to turn the other while holding one of the side handle 4 and the upper handle 5. For example, by tightening the upper handle 5 while holding the side handle 4 and fixing the guide tube 2 and its outer cover, the cylinder rod 1 can be tightened to the extra length H.

  In the first embodiment, two L-shaped handles that are bent outward in plan view are provided on the diagonal line of the cylinder rod 1 in plan view. Specifically, the grip portion is fixed to the upper surface of the cylinder exterior 10 and extends upward from the fixed portion in the same direction as the stroke direction. The grip portion extends in the radial direction in a plan view on the front side bent from there.

(Jack-up method for ground anchor maintenance (How to use anchor maintenance jack))
The anchor maintenance jack having the above-described configuration can be used by a method of performing additional tightening to the extra length portion H as described below, for example, when jacking up an existing ground anchor for maintenance.

  That is, as a jack-up method for maintenance of an existing ground anchor, (a) an anchor in which an internal screw structure is directly screwed into an external screw of the extra length H and the anchor maintenance jack is screwed and fixed to the extra length H. Maintenance jack mounting process, (b) a jackup process in which the extra length H is jacked up with the ring nut N by increasing the stroke of the cylinder rod 1, and (c) a ring screwed into the extra length H that has been jacked up. A ring nut N retightening process in which the nut N is tightened downward in the axial direction and brought into contact with the bearing plate P, and (d) the cylinder rod 1 and the guide tube 2 are separated from the bearing plate P by reducing the stroke of the cylinder rod 1. Stroke down process to make it floated and (e) Retighten the internal screw structure, And an internal screw structure retightening step in which the cylinder rod 1 and the guide tube 2 are brought into contact with the bearing plate P in an integrated manner, and then, the stroke length of the cylinder rod 1 is further increased. The jackup process of jacking up with the ring nut N is then performed. Hereinafter, each process in the jacking-up method of the existing ground anchor using Example 1 is explained in full detail.

(A) Anchor maintenance jack attachment process As an anchor maintenance jack attachment process, first, the anchor maintenance jack of the present invention is set in advance as a "lower end stroke state S1" in which the stroke position of the cylinder rod 1 is the lower end. It is screwed and attached to the extra length H in the state S1 ". Specifically, the attachment to the surplus length portion H is performed by aligning the lower end of the cylinder rod 1 with the upper end of the surplus length portion H and turning the entire anchor maintenance jack by the side handle 4 or the upper handle 5 to screw into the surplus length portion H. Thus, the contact surface 24b of the guide tube 2 is brought into contact with the support plate P (Fig. 3). In this initial state, the ring nut N attached to the extra length H is pressed against the support plate P at the lower end of the extra length H.

(B) Jack-up process Next, as a jack-up process, the anchor maintenance jack is jacked up by the hydraulic pressure of the hydraulic mechanism 3 with the leg surface in contact with the anchor maintenance jack mounting process. The cylinder rod 1 is stroked in the direction of the thick arrow in FIG. 3 by pressurization, and the “upper end stroke state S2” (FIG. 4) in which the stroke position of the cylinder rod 1 is the upper end from the “lower end stroke state S1” (FIG. 3). It becomes. As a result, the extra length H is jacked up and pulled up by one stroke length ls. At this time, the ring nut N is in a state of being lifted from the bearing plate P by one stroke length ls together with the jacking up of the extra length H while being screwed into the extra length H (FIG. 4). At this time, the leg surface contact state continues.

(C) Ring nut N retightening step Next, as the ring nut N retightening step, the leg surface contact state, the upper end stroke state S2 that has undergone the jack-up step, and the ring nut N is lifted from the bearing plate P The ring nut N floating from the bearing plate P together with the jacking up of the extra length H from the operation window 25 of the guide tube 2 is kept at the base end side of the extra length H (FIG. 4). The ring nut N is in contact with the pressure plate P by screwing in the direction of the pressure plate P (indicated by the thick arrow).

  Thereby, the jack-up state of the extra length portion H that has been jacked up is maintained regardless of the pressurization state of the hydraulic mechanism 3. This is because, even when the hydraulic mechanism 3 is depressurized as described in D below, a contact pressure in the direction of the bearing plate P is generated in the ring nut N by the anchor force in the underground direction. In addition, the contact leg surface 24b of the guide tube 2 remains in the leg surface contact state in contact with the bearing plate P (FIG. 5).

(D) Stroke down process Then, as a stroke down process, the ring nut N is in contact with the bearing plate P through the ring nut N retightening process (the leg contact state, the upper end stroke state S2). In addition, the hydraulic pressure of the hydraulic mechanism 3 is reduced while the ring nut N is in a contact state, and the state is shifted from the “upper end stroke state S2” to the “lower end stroke state S1”. At this time, as shown in (c), the jack-up state of the extra length H is maintained by the contact pressure of the ring nut N in the direction of the bearing plate P as shown in FIG. For this reason, as the pressure is reduced, the entire anchor maintenance jack slides upward while maintaining the screwed state, and shifts from the state shown in FIG. 5 to the state shown in FIG. The contact leg surface 24b of the guide tube 2 shifts from the contact state to the leg surface separated state in which the contact leg surface 24b is separated from the pressure bearing plate P by pressure reduction (FIG. 6).

(E) Inner screw structure retightening step Next, as the inner screw structure retightening step, from the leg surface separation state in the lower end stroke state S1 and the ring nut N contact state after the stroke down step as shown in FIG. As in (a) above, by rotating the cylinder rod 1 with the upper handle 5, it is screwed in the direction of the pressure plate P (the direction indicated by the thick arrow in FIG. 6) on the base end side of the extra length H, and the guide tube 2 The abutment leg surface 24b is in a contact state with the leg surface in which the abutment leg surface 24b abuts against the bearing plate P (FIG. 7). At this time, the side handle 4 is held and fixed, and the cylinder tube 1 alone is turned while holding the guide tube 2 so as not to turn. Thereby, the anchor maintenance jack can be screwed in the direction of the bearing plate P without removing the hydraulic hose 33 from the hydraulic connection port 32. Therefore, the work procedure is simplified and the maintenance work becomes easier.

(F) Re-jacking step or inner screw structure retightening step After the inner screw structure retightening step, if further lifting of the extra length H is necessary, following the inner screw structure retightening step, The process from (b) the jack-up process to (d) the stroke-down process or (b) the process from the jack-up process to (e) the internal screw structure tightening process is repeated as many times as appropriate. By repeating the steps (b) to (e) several times, as shown in FIG. 8, it becomes possible to pull the anchor up to the state where the extra length H penetrates the through hole 11 opened in the vertical direction. . The extra length H is held in a state where it is jacked up by the ring nut N additional tightening process, and the anchor maintenance jack is attached to the extra length H by the stroke down process and the additional tightening process, and the extra jack has been jacked up more than once. The long portion H can be further jacked up by a simple and quick process. According to these series of steps, the stroke length ls is made relatively short in consideration of the rigidity of the jack structure portion (cylinder rod 1 and guide tube 2) of the anchor maintenance jack and the weight of the hydraulic mechanism 3. However, continuous jack-up with a limited stroke length ls or more can be easily performed. For this reason, for example, the maintenance work can be efficiently performed by using an anchor maintenance jack that is relatively small and lightweight. Here, the term “small and light” refers to a specification such as a total length (axial length) of about 200 to 300 mm, a weight of about 20 to 30 kg, or a stroke length of ls 60 to 150 mm.

  9 and 10 are a perspective explanatory view and a plan view explanatory view, respectively, of an anchor maintenance jack according to a second embodiment of the present invention. FIG. 11 is a cross-sectional explanatory view taken along the line AA of FIG. 10, illustrating a front view state at the stage of attachment to the extra length H as an example of use of the anchor maintenance jack of the second embodiment. In the second embodiment, the configuration of the cylinder rod 1 (first, second, third... Internal screw structures 1a, 1b, 1c. Etc.), the shape of the side handle 4 and the presence or absence of the upper handle 5 are different. Other configurations are the same as those of the first embodiment. Hereinafter, each configuration of the second embodiment different from the first embodiment will be described in detail.

(Cylinder rod 1)
The first, second, and third inner screw structures 1a, 1b, 1c,... In Example 2 have different inner screw structures 12 having different inner diameters by combining any one or a plurality thereof. The extra length H can be adapted to the outer diameter type. Specifically, the first inner screw structure 1a, the second inner screw structure 1b, and the third inner screw structure 1c have different outer diameters and inner diameters, and the cylinder exterior 10 and the first inner screw are different from each other. The structure 1a, the first inner screw structure 1a and the second inner screw structure 1b, and the second inner screw structure 1b and the third inner screw structure 1c can be screwed together in a nested manner. It has become. Then, the inner screw structure 12 of each of the inner screw structures 1a, 1b, 1c,... Appears as a through hole 11 that can be screwed into the extra length portion H, thereby reducing the inner diameter of the inner screw structure 12. It can be adjusted.

  The plurality of inner screw structures 1a, 1b, 1c... Or between the first inner screw structure 1a and the cylinder exterior 10 includes a fixing hole 14b and a fixing screw 14a screwed into the fixing hole 14b. Consists of. The first, second, third,... Inner screw structures 1a, 1b, 1c,... Have a disk-like flange having an outer diameter larger than that of the cylinder at the upper part of the cylinder with a screw cut on the inner and outer surfaces. It is fixed (see, for example, 1a in FIG. 9). The fixing hole 14b is provided vertically in the protruding portion of the disk-like flange (circular portion protruding outward from the cylindrical outer shape) through the thickness direction of the disk-like flange. The fixing screw 14a screwed from above into the fixing hole 14b passes through the disk-like flange up and down, and then the tip is pressed downward to fix it.

  In the second embodiment, the distance from the lower surface of the side protrusion 13 to the lower end of the cylinder exterior 10 is larger than “the stroke length ls and the lower pressing portion thickness 23 t”. In other words, the cylinder downward length of the cylinder exterior 10 extending downward from the side protrusion 13 exceeds the substantial stroke portion Els and the lower pressing portion thickness 23t. Thereby, the lower end of the cylinder rod 10 is always positioned below the lower pressing portion 23 to ensure sufficient rigidity and a stable stroke. Further, the screwing section can be made longer, and the fixing to the extra length portion H is made more reliable and safe. In the second embodiment, the upper handle 5 on the upper surface of the cylinder rod 1 is not provided.

(Strain gauge 27)
The strain gauge 27 of Example 2 is the left and right side surfaces and the inner side surface of each of the four leg portions 24, and both are attached at the same height (FIGS. 10 and 11). By installing each leg portion 24 so as to surround the three side surfaces, it is possible to accurately grasp the uneven load applied to the leg portion 24. Further, by providing not on the outer surface of the leg portion 24 but on the inner side surface of the leg portion 24 and the left and right side surfaces of the leg portion 24 which is the side periphery of the operation window 25, erroneous contact during operation is prevented and more accurate measurement is performed. Can be done.

(Side handle 4)
The side handle 4 of the second embodiment is fixed radially from the outer periphery of the anchor maintenance jack as in the first embodiment. However, as shown in FIG. It is bent in one direction. Moreover, as shown in FIG. 9, a grip part is provided in an up-down direction in a bending part and a front-end | tip part. With this configuration, the anchor maintenance jack can be transported or operated easily and reliably using the handle 4, and anchor maintenance can be performed more safely using the anchor maintenance jack that is often installed at high places or inclined surfaces. sell.

  In addition, this invention is not limited to the structure of said each Example, A various structure change is possible in the range which does not deviate from the meaning of invention.

  FIG. 12: is each perspective explanatory drawing of the anchor maintenance jack of Example 3 of this invention, and shows the cross-sectional top view explanatory drawing which passes along an axis | shaft. FIGS. 13 and 14 are cross-sectional plan views illustrating the anchor maintenance jack according to the third embodiment of the present invention, and are examples of using the leg surface contact state and the lower end stroke state S1, respectively (the diagram of the first embodiment). 3), and a usage example (a state similar to the state of FIG. 6 of Example 1) in a state in which the ring nut N is in contact with each other in the leg surface separated state and the lower end stroke state S1. The third embodiment is different from the second embodiment in that the configuration of the cylinder rod 1 (first, second, third... Internal screw structures 1a, 1b, 1c. Etc.), the presence / absence of a leg unit composed of the leg 24 and the inter-leg bridge 26, the presence / absence of the strain gauge 27, and the number of systems constituting the hydraulic mechanism 3 are different. Other configurations are the same as those of the second embodiment. Hereinafter, each configuration of the third embodiment different from the second embodiment will be described in detail.

(Inner screw structure 1a, 1b, 1c ...)
The internal screw structures 1a, 1b, 1c,... Of Example 3 are formed of a cylinder having a through hole 11 therein, and a disk-shaped perforated flange having an outer shape larger than that of the cylinder is fixed to the upper part. The upper handle 5 is fixed to the upper part of the disk-like perforated flange. The through-hole 11 is provided in the up-down direction through the thickness direction of the disk-shaped flange at the protruding portion of the disk-shaped flange (circular portion protruding outward from the cylindrical outer shape). An internal screw structure is provided from the lower end of the through-hole 11 to the vicinity of the center in the length direction. The disc-shaped flange protrudes laterally from the cylinder of the inner screw structures 1a, 1b, 1c... At the upper ends of the inner screw structures 1a, 1b, 1c. The lower surface is in contact with the upper end surface of the cylinder exterior 10, and the inner screw structures 1a, 1b, 1c,. When the cylinder exterior 10 is stroked by jacking up, the disk-shaped flanges of the inner screw structures 1a, 1b, 1c,... Are pushed up, and are thereby screwed and fixed to the inner screw structures 1a, 1b, 1c,. The extra length portion H is pulled up. Two upper handles 5 are fixed at equal intervals on the upper surfaces of the disk-shaped flanges of the inner screw structures 1a, 1b, 1c.

    The first, second, and third inner screw structures 1a, 1b, 1c,... Of Example 3 have different inner diameters of the inner screw structure 12 by selecting and replacing any one of them. The extra length H can be adapted to the outer diameter type. Specifically, the first inner screw structure 1a, the second inner screw structure 1b, and the third inner screw structure 1c have the same outer diameter and different inner diameters. Each of the body 1a, the second inner screw structure 1b, and the third inner screw structure 1c can be individually accommodated inside the cylinder exterior 10. The inner screw structures 12 of the inner screw structures 1a, 1b, 1c,... Correspond to the extra length portions H having different outer diameters. Thereby, even when the diameter of the extra length portion H differs depending on the type, the inner screw structures 1a, 1b, 1c,... The inner diameter can be adjusted.

    Specifically, the cylinders of the inner screw structures 1a, 1b, 1c,... Of the third embodiment have an outer shape that can be inserted into the inner hole of the cylinder exterior 10 and a through-hole that can be inserted through the extra length H of the ground anchor. 11 and an inner shape. The insertion hole of this cylindrical body penetrates from the upper end to the lower end, starts from at least the lower end of the insertion hole, and is provided with an internal screw structure that extends upward, that is, toward the surface in the axial direction. The cylinders of the internal screw structures 1a, 1b, 1c,... Of the third embodiment are provided with a predetermined clearance (for example, 1 mm to 2 mm) from the inner surface of the cylinder exterior 10. The cylindrical outer surface of the inner screw structures 1a, 1b, 1c,... Slides or moves in the inner hole of the cylinder exterior 10, so that the inner screw structures 1a, 1b, 1c,. The inside of 1 is accommodated so that free rotation is possible.

(Leg unit)
In the leg unit of the third embodiment, four leg portions 24 and an inter-leg bridge 26 that connects the adjacent leg portions 24 are integrally formed, and are erected on the support plate P. The leg unit upper surface 24t is provided with a mortar-shaped conical concave surface whose apex is on the axis of the lower ground anchor. At the same time, a conical convex surface that can be fitted to the conical surface is provided on the lower surface 23 b of the lower pressing portion 23 of the guide tube 2. The guide tube 2 and the leg unit are fitted into the conical surface by the contact of both the conical surfaces, and the leg unit supports the guide tube 2 and the cylinder rod 1. When the inner screw structures 1a, 1b, 1c... Are screwed into the extra length H and screwed downward by this conical surface fitting, the conical convex surface of the lower pressing portion 23 is on the conical concave surface of the leg unit. , And the center of the leg unit is moved to the center position common to the axis of the ground anchor, so that the so-called centering of the leg unit is automatically performed. As a result, even if the leg unit can be separated from the cylinder rod 1 and the guide tube 2 and the like, the leg unit can be easily arranged at an accurate position, and the jack-up can be performed evenly and accurately in the circumferential direction. Further, by making the leg unit separable from the cylinder rod 1 and the guide tube 2 and the like, the cylinder rod 1 having an internal screw structure is reduced in weight, and the attachment to the extra length H is greatly facilitated.

(Strain gauge 27)
A plurality of even-numbered strain gauges 27 are affixed to the leg unit at symmetrical positions about the axis of the ground anchor. In Example 3, the side upper part of the leg part 24 and the lower part of the inter-leg bridge 26 are connected by the curved part of the curved boundary, and the strain gauge 27 is attached to the curved part (FIG. 12). That is, the operation window 25 of the third embodiment is a flat rectangular window opened downward, and the upper left and right corners of the rectangular shape are curved portions. Two strain gauges 27 are provided for each operation window 25 along the bent portion. This position is a side surface of the four leg portions 24 and is a position with few erroneous contacts. Also, this bent part is a place where a lot of concentrated load is applied to the leg unit when jacking up, and the strain amount of the leg unit can be measured efficiently, so that the tensile force of the ground anchor can be measured more accurately. sell.

(Hydraulic mechanism 3)
The hydraulic mechanism 3 according to the third embodiment is provided with two upper and lower hydraulic connection ports in one hydraulic chamber 31. The lower side is a pressurizing hydraulic connection port 32 and is connected to a pressurizing hydraulic hose 33, and the upper side is a depressurizing hydraulic connection port 32 and is connected to a depressurizing hydraulic hose 33. By using two systems of oil transportation, pressurization and decompression, pressurization and decompression can be performed efficiently.

(Tensile test of existing ground anchor)
In the anchor (N = 34) constructed on the farm road mountain side cut slope of Sakai City, A Prefecture, a tensile test was conducted by using a ground anchor of Example 3 of the present invention and a conventional center hole jack, respectively. -The measurement results of displacement were compared and evaluated. The test anchors (N = 2) are all Super Flotech Anchor SFL-3, Design Anchor Force / Fixing Load 437.0kN, Drilling Hole Soft Rock I of Anchoring Part (Ambient Surface Friction Resistance τ = 1.00N) / Mm ² ), the confirmation test implementation date at the time of construction is 16 months before the test date. Free length and anchor length are test anchor NO. 1 is 4.0 m and 5.7 m, NO. 2 is 16.2 m and 6.0 m. In the evaluation, the ground anchors were lifted off (monotonically loaded) with two types of jacks of the same anchor: a testing machine and a center hole jack, and the results were compared. FIG. 1 (first test with center hole jack (a), later test with anchor maintenance jack of the present invention (b)), FIG. 2 is a test result (first test (a) with the anchor maintenance jack of the present invention and later test (b) with the center hole jack). The load at the inflection point represents the effective tension. As a result of the test, the inflection point appears at a load close to that of the center hole jack and the anchor maintenance jack of the present invention. However, the anchor maintenance jack of the present invention has a smaller variation in the effective tension than the center hole jack. In addition, the displacement curve up to the effective tension appears in a substantially straight line with a smaller and slower increase rate. This is because the anchor maintenance jack according to the present invention directly engages the anchor head with the cylinder rod 1 and does not use an extension rod or the like for extending the extra length H. The main cause is thought to be a reduction in measurement noise.

  The main specifications of the anchor maintenance jack of the third embodiment of the present invention are: capacity: 500 kN, total weight 20 kg (total weight including two configurations of a guide tube main body integrated with the cylinder rod 1 and the like, and a leg unit), Total length: 20 cm, stroke amount 11 cm. The structure consists of a structure including a cylinder external 10 rod and a leg unit, and does not include a ram chair, a tension bar, a tension coupler, or a lock nut.

  The main specifications of the conventional center hole jack to be compared are: capacity: 500kN, total weight about 55kg (center hole jack + ram chair + locking nut + tension bar + tension coupler), total length: about 70cm, stroke amount: about 30 cm. The configuration includes a ram chair, tension bar, tension coupler, center hole jack, and locking nut.

(Operational effect of the present invention)
According to the present invention, the following effects can be achieved.

  (A) The degree of soundness can be evaluated by any anchor work as long as there is certain data. In other words, it is not always necessary to conduct a field survey. As a result, it will be possible to investigate, maintain and repair anchor works that require efficient and focused measures, and as a result contribute to the maintenance of safe and comfortable social and economic activities.

  (B) It is a clue to clarify how various factors such as ground conditions, groundwater presence, etc., which are currently unknown, influence the deterioration of the anchor, and it is also used as design information it can. If the superiority of anchor work can be evaluated at the time of design, it will be possible to construct anchor work only when the life cycle cost is really low, and the value of social capital will be improved.

  (C) Deterioration prediction can be performed by changing the elapsed years on the model of the anchor work in service. This makes it possible to estimate in advance the locations and costs that require maintenance, and contribute to leveling maintenance costs and reducing administrative costs.

According to the anchor maintenance jack of the present invention, it is possible to speedily collect data relating to the soundness level of the anchor work, thereby solving the following problems. The challenge is
(1) There is no dedicated equipment for the tension test of the conventional anchor method, even if it is large and heavy, and the tension test after construction requires installation of scaffolding, loading / unloading of equipment with a crane, etc. The challenges of time, cost, danger, impact on economic activity, and
(2) The conventional test equipment needs to be rented from each material maker, etc., which is a problem that the investigation cost increases.

  The anchor maintenance jack of the above embodiment of the present invention is lighter and more compact than conventional test equipment. Further, since there are adjusters corresponding to various anchors, it is possible to cope with various sizes of ground anchors having different sizes of members for installing the equipment depending on the construction method, ability and the like. Furthermore, since the strain of the test equipment can be made extremely small, more accurate displacement can be obtained for the tensile force of the ground anchor before and after the inflection point by a change curve with less strain, and the analysis should be performed in detail. Can more accurately evaluate the health of the ground anchor. Furthermore, it is possible to load and fix the tension, and to load and unload, that is, it is possible to remove the looseness and overstress that were discovered during the investigation on the spot. By these, it is possible to solve the problems of the conventional test equipment.

  Ground anchors that have already been installed after passing through a fixing test at the time of construction on the ground are mainly attached, and can be used as a maintenance jack for such ground anchors. Above all, it can be used as a measuring instrument for evaluating the degree of soundness after the passage of ground anchors including effective tension, and it can also be used as a re-tensioning jack that applies re-tensioning force as necessary.

The perspective explanatory view of the anchor maintenance jack of Example 1 of the present invention. FIG. 3 is an explanatory plan view of the anchor maintenance jack according to the first embodiment. FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing a usage example (a leg surface contact state and a lower end stroke state S1) in the anchor maintenance jack of the first embodiment. FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing an example of use in the anchor maintenance jack of the first embodiment (a state in which the ring nut N is lifted in a leg surface contact state and an upper end stroke state S2). FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing an example of use in the anchor maintenance jack of the first embodiment (a state in which the ring nut N is in contact with the leg surface in contact with the upper end stroke state S2). FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing an example of use in the anchor maintenance jack of the first embodiment (a state in which the ring nut N is in contact with the leg surface in a separated state and a lower end stroke state S1). FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing a usage example (a leg surface contact state and a lower end stroke state S1) in the anchor maintenance jack of the first embodiment. FIG. 3 is an AA cross-sectional explanatory view of FIG. 2 showing an example of use in the anchor maintenance jack of the first embodiment (a state in which the ring nut N is in contact with the leg surface in a separated state and a lower end stroke state S1). The perspective explanatory view of the anchor maintenance jack of Example 2. FIG. Plane view explanatory drawing of the usage example of the anchor maintenance jack of Example 2. FIG. FIG. 10 is an AA cross-sectional explanatory view of FIG. 10 illustrating an example of use in the anchor maintenance jack of the second embodiment. The perspective explanatory view of the anchor maintenance jack of Example 3. Sectional explanatory drawing which shows the usage example in the anchor maintenance jack of Example 3. FIG. Sectional explanatory drawing which shows the usage example in the anchor maintenance jack of Example 3. FIG. Cross-sectional explanatory drawing which shows the ground anchor used as the attachment object of the anchor maintenance jack of this invention. Cross-sectional explanatory drawing which shows the ground anchor used as the attachment object of the anchor maintenance jack of this invention. The displacement-load diagram which shows the measurement result when a tensile test is done in order of the anchor maintenance jack (a) and the center hole jack (b) of the present invention. The displacement-load diagram which shows a measurement result when a tensile test is done in order of the center hole jack (a) and the anchor maintenance jack (b) of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder rod 1a 1st internal thread structure 1b 2nd internal thread structure 1c 2nd internal thread structure 10 Cylinder exterior 11 Through-hole 12 Internal thread structure 13 Side protrusion 14a Fixed screw 14b Fixed hole 2 Guide Tube 21 Side peripheral covering portion 22 Upper pressing portion 23 Lower pressing portion 23t Lower pressing portion thickness 24 Leg portion 24b Abutting leg surface 25 Operation window 26 Leg bridge 27 Strain gauge 3 Hydraulic mechanism 31 Hydraulic chamber 32 Hydraulic connection port 33 Hydraulic pressure Hose 4 Side handle 5 Upper handle Els Substantially stroke part H Extra length part H
ls Stroke length N Ring nut P Bearing plate S1 Lower end stroke state S2 Upper end stroke state

Claims (7)

  An anchor maintenance jack capable of jacking up an extra length portion provided with an external screw on the ground surface side of an existing ground anchor, wherein the internal screw structure is engaged with the external screw of the extra length portion, and the internal screw structure is grounded. A cylinder rod that is pulled up by a stroke toward the axial surface of the anchor, and a guide tube that guides the stroke of the cylinder rod around the cylinder rod, and the inner screw structure has a substantial stroke of the cylinder rod. An anchor maintenance jack characterized by being provided at an axial height that overlaps at least a portion of the portion.   An internal screw structure that can be accommodated inside the cylinder rod is provided, and the internal screw structure includes a through-hole through which the extra length portion can penetrate and the internal screw structure that extends upward from the lower end of the through-hole. The anchor maintenance jack according to claim 1 provided.   The anchor maintenance jack according to claim 2, wherein a plurality of internal screw structures having different inner diameters are exchangeably accommodated in the cylinder rod.   The anchor maintenance jack according to claim 2 or 3, wherein the inner screw structure is fitted to the cylinder rod at the upper end and is accommodated in the cylinder rod so as to be freely rotatable (rotatable) with respect to the cylinder rod. .   A leg unit standing on the bearing plate and supporting the cylinder rod and the guide tube is provided, and a plurality of strain gauges are arranged on the leg unit so as to be symmetrical with respect to the anchor axis of the ground anchor. The anchor maintenance jack according to claim 1, 2, 3, or 4 provided.   2. A leg unit for supporting a cylinder rod and a guide tube by standing on a support plate and fitting a conical surface with a lower end of the guide tube or the outer cover at the upper end. The anchor maintenance jack according to 4, or 5.   An anchor having an inner screw structure that can be screwed into an extra length portion of a ground anchor, a cylinder rod that can be stroked along the axial direction of the ground anchor, and a leg portion that supports these and stands on a bearing plate. A jack-up method for an existing ground anchor that uses a maintenance jack to jack up the extra length of the existing ground anchor, with an internal screw structure on the outer screw of the extra length of the ring nut screwed To fix the anchor maintenance jack, jack up the extra length part with the ring nut by increasing the stroke of the cylinder rod, and tighten the ring nut screwed to the extra part that was jacked up to contact the bearing plate. Contact the cylinder rod, stroke the cylinder rod down, and lift the cylinder The guide tube is lifted, the internal screw structure is tightened, the legs are brought into contact with the bearing plate integrally with the guide tube, and the jacked up extra portion is further jacked up by increasing the stroke of the cylinder rod. A jack-up method of an existing ground anchor characterized by the above.

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