JP3760335B2 - Ground anchor construction using trumpet pipe and trumpet pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ground anchor method using a trumpet tube and a trumpet tube used in the method.
[0002]
[Prior art]
Ground anchor method is a method used to prevent unstable collapse or peeling by bonding unstable ground or rock directly to stable ground or rock, and drilling holes in the base to inject cement mortar etc. The anchor body is formed by the following three basic elements.
"Anchor head": A part that allows force from the structure to be transmitted to the tension part as a tension force.
"Tensile part": A part that transmits the tensile force to the anchor body in the base.
"Anchor body": A part that transmits the tensile force from the tension part to the base and resists it.
[0003]
As shown in FIG. 5, the general construction method of the ground anchor method is to insert the casing pipe 6 into a drilling hole drilled to a depth reaching the base with a rotary percussion drilling machine, for example [FIG. . Then, the grout material G is filled into the casing pipe 6 and the tendon 7 (tensile material) is inserted through the casing pipe 6 as shown in FIG. Next, the grout material G is injected under pressure while the casing pipe 6 is pulled out as shown in FIG. The tension layer is tensioned between the anchor body formed in the stable layer in this way and the structure provided on the ground surface, whereby the unstable layer is reinforced [Fig. (E)].
[0004]
The main feature of the ground anchor work is a tightening function that presses and stabilizes the slope where there is a risk of slipping by prestressing the tension part. The tensile strength of the tensile part is used to prevent the landslide mass from trying to slide, but unlike the pile work, by applying a certain amount of prestress to the tensile part at an early stage, the elongation of the tensile part ( There is an initial detent function that can increase the deterrent effect when the amount of deformation due to landslide is small. In addition, there is a sewing function in which the anchor body is formed across the sliding surface and the strength of the sliding surface is increased by the tensile strength of the tensile portion.
[0005]
[Problems to be solved by the invention]
As described above, it goes without saying that the most expected effect in adopting the ground anchor method as the slope reinforcing work is that a prestress is applied to the tension portion. However, in the conventional ground anchor construction, the prestress, which is the greatest feature, is hardly structurally applied.
[0006]
This is because the portion of the unstable layer to be compressed is continuously integrated with the anchor body by the injection of the grout material. Such a phenomenon occurs in the casing pressure injection method. Prestress applied to the anchor head is applied to the grout material that has penetrated to the portion to be compressed, and the unstable layer is not damaged unless the grout material in this portion is broken. No compression zone will occur. Even if the grout material breaks, the compression is limited to the fracture locality, and unless the tensile property of the grout material is lost throughout the unstable layer, the substantial function of the ground anchor construction cannot be fully exhibited. .
[0007]
[Means for Solving the Problems]
Therefore, the present inventor has achieved the present invention as a result of intensive studies in view of the above problems, and the feature of the present invention is that in the ground anchor method, the grout material is used for the casing pipe in the ground anchor work. After forming the anchor body in the base by press-fitting, a trumpet pipe constituted by a pipe part having a diameter having a gap with the tensile material and a diameter-enlarging part provided at the tip part of the pipe part and communicating with the pipe part Is inserted into the casing pipe, and the grout material between the casing pipe and the trumpet pipe is discharged through the pipe section of the trumpet pipe.
[0008]
Alternatively, in ground anchor work, after a grout material is press-fitted into a casing pipe to form an anchor body in the base, a pipe portion having a diameter having a gap between the tensile material and a tip portion of the pipe portion is provided. A trumpet pipe constituted by an enlarged diameter portion communicating with the casing pipe is inserted into the casing pipe, and a trumpet pipe stopper sheath is attached to an end portion of the trumpet pipe to form a structure fixing portion. .
[0009]
In the invention of the object, in the ground anchor work, the grout material is press-fitted into the casing pipe to form an anchor body in the base, and then inserted into the casing pipe, between the tensile material and A pipe portion having a diameter having a gap and a diameter-increased portion provided at the tip portion of the pipe portion and communicating therewith.
[0010]
Alternatively, in the ground anchor work, after the grout material is press-fitted into the casing pipe to form an anchor body in the base, the pipe portion having a diameter between the tensile material and the pipe portion inserted through the casing pipe and the pipe A trumpet pipe formed by a diameter-expanding portion provided at the tip portion of the portion and communicatively connected thereto is slidably attached to the end portion of the pipe portion, and the main body is constituted by a bellows body.
[0011]
Here, the “anchor body” as used in this specification means that a casing pipe is inserted into a hole drilled by a drilling machine to the depth from the ground surface to a stable base, and cement milk or cement mortar is inserted into the casing pipe. It refers to a lump formed in the base by press-fitting grout material. There are various hole drilling machines, for example, a rotary percussion type and a down-the-hole hammer type. In the rotary percussion type, the anchor body is formed by press-fitting the grout material while pulling out the casing pipe, but in the down-the-hole hammer type, the anchor forming portion is drilled in a series of processes, and the anchor body is not pulled out. It is formed.
[0012]
“Tensile material” refers to a steel material that is prestressed by embedding one end in an anchor body and pulling the other end from the ground surface side. Generally, a PC steel strand, a PC steel composite wire bundle, a PC steel rod, or the like is used. Usually, a tensile material is covered with a sheath and a rust preventive material such as grease is enclosed inside. In general, an apartment or a fixing body is called a tendon.
[0013]
“Trumper pipe” refers to a member for removing the grout material filled in the casing pipe. This is because the grout material is pressurized and injected into the casing pipe to form an anchor body, and then the trumpet pipe is inserted into the casing pipe to discharge the grout material and anchor the tensile force of the anchor head. This is to ensure that it is transmitted to the body. The insertion length of the trumpet tube is basically up to the anchor body. That is, it is fundamental to remove almost all of the grout material between the casing pipe and the trumpet tube and to prevent the anchor body injection grout material from flowing out to the free length portion.
[0014]
However, the greatest object of the present invention is to prevent the portion to be compressed of the unstable layer from being continuously integrated with the anchor body by the injection of the grout material, thereby preventing the compression zone from being generated in the unstable layer. For this reason, a part of the grout material between the casing pipe and the trumpet pipe may be removed by inserting the trumpet pipe to such an extent that a compression region is generated in the unstable layer (the length not reaching the anchor body).
[0015]
The trumpet tube is constituted by a pipe portion and a diameter-expanded portion provided at and communicated with the pipe portion. The pipe portion is a portion that fits into the tensile material, and the grout material is discharged through the pipe portion. For this reason, the inner diameter of the pipe portion is a diameter that creates a gap with the tensile material. The material is not particularly limited, but it is preferable to reduce the weight with a plastic such as aluminum or polyvinyl chloride.
[0016]
The enlarged diameter portion is provided at the tip of the pipe portion to introduce the grout material in the casing pipe into the pipe portion, and has a truncated cone shape or a bowl shape. The material is made of a soft material such as rubber, leather, synthetic rubber, or synthetic leather, and is made to follow the inner peripheral surface of the casing pipe. It is preferable to remove even the grout material on the inner peripheral surface portion of the casing pipe at the enlarged diameter portion, but even if it remains to some extent, it may be easily broken when the tension material is tightened or removed when the casing pipe is pulled out. Accordingly, the diameter of the casing pipe may be a diameter where a gap is generated, and even when formed of a hard member such as metal or plastic, most of the grout material that hinders the tension of the anchor body can be removed.
[0017]
It is preferable to provide a guide member on the distal end side of the enlarged diameter portion. This is because if there is a portion with a different diameter such as a coupling in the casing pipe, the enlarged diameter portion may be caught and cannot be inserted further. As the guide member, pin-shaped members such as metal and plastic are provided at appropriate intervals. In this case, the guide member is provided so as to be inclined inward so as not to be caught by the different diameter portion, or the tip portion is bent inward.
[0018]
In the conventional ground anchor construction, the anchor molding is completed when the grout material is press-fitted to form the anchor body. After that, curing, tension / fixation, rust prevention, etc. are applied to complete. Therefore, in the construction method according to the present invention, the anchor formation is terminated at the stage where the trumpet pipe is inserted, and the rest is completed by a method similar to the conventional method. The trumpet tube may be pulled out after the grout material is removed or left as it is.
[0019]
In the method of the present invention, a trumpet tube stopper sheath is further provided at the end of the pipe portion of the trumpet tube inserted into the casing pipe. This is a member for processing the head when the inserted trumpet tube is left as it is. In other words, the trumpet tube should not cause a beam effect between the anchor head and the anchor body. Another object is to enhance the rust prevention effect by sealing the trumpet tube end. For this reason, the trumpet tube stopper sheath is formed with a bellows body or is slidably attached to the pipe portion of the trumpet tube.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments of the invention shown in the drawings.
[0021]
FIG. 1 is an example of an embodiment of a ground anchor construction using a trumpet pipe according to the present invention, and shows an example of drilling with a down-the-hole hammer drilling machine. First, the hole which penetrates the casing pipe 6 and the hole which forms the anchor body 9 are drilled like (a) and (b). And the casing pipe 6 and tendon (tensile material) 7 are inserted like (c). Next, as shown in (d), the grout material G is pressurized and injected into the casing pipe 6 to form the anchor body 9. The steps up to here are the same as those of the conventional ground anchor method.
[0022]
In the present invention, when the anchor body 9 is formed, the grout material G in the casing pipe 6 is discharged by inserting the trumpet pipe 1 into the casing pipe 6 as shown in (e). After discharging the grout material G, the casing pipe 6 is completely pulled out (f), tensioned (g), and fixed (h) in the same manner as a general ground anchor work.
[0023]
FIG. 2 shows an example of the embodiment of the trumpet pipe 1 for ground anchor construction according to the present invention. As shown in FIG. The diameter portion 3 is provided with a guide pin 4 as a guide member at the tip as shown in FIG. In this example, an example is shown in which a trumpet tube stopper sheath 5 for processing the head of the trumpet tube 1 inserted is attached.
[0024]
FIG. 3 shows the state of use of the trumpet tube 1. By inserting the trumpet pipe 1 into the casing pipe 6, the grout material G stirred in the enlarged diameter portion 3 is discharged through a gap with the tendon 7 inside the pipe portion 2. The state to be made is shown. Further, in this example, even when there is a different diameter portion due to the presence of the coupling 8 in the casing pipe 6, the enlarged diameter portion 3 can be deformed and moved by the guide pin 4 as shown by a chain line in the figure.
[0025]
As shown in FIG. 4, the anchor structure constructed by the ground anchor construction using the trumpet pipe according to the present invention does not have a free length portion that inhibits compression by the tendon 7, and the tensile force from the tensile portion is reduced. It can be reliably transmitted to the anchor body 9, and the secondary tension can be effectively performed.
[0026]
【The invention's effect】
As described above, in the ground anchor work using the trumpet pipe according to the present invention, in the ground anchor work, after the grout material is press-fitted into the casing pipe to form the anchor body in the base, a gap is formed between the tensile material and the ground material. A trumpet pipe formed by a pipe portion having a diameter and an enlarged diameter portion provided at the tip end portion of the pipe portion and communicating with the pipe portion is inserted into the casing pipe, and between the casing pipe and the trumpet tube. The grout material is discharged through the pipe part of the trumpet pipe. Alternatively, in ground anchor work, after a grout material is press-fitted into a casing pipe to form an anchor body in the base, a pipe portion having a diameter having a gap between the tensile material and a tip portion of the pipe portion is provided. By inserting a trumpet tube constituted by the enlarged diameter portion communicating with the casing pipe into the casing pipe and attaching a trumpet tube stopper sheath to the pipe portion end of the trumpet tube to form a structure fixing portion, The function of the ground anchor can be fully utilized without restricting the elastic function of the free length portion.
[0027]
Moreover, the damage of the sheath due to ground disturbance can be protected by attaching the trumpet tube, and the anticorrosive effect of tendon can be enhanced. In addition, the triple structure of the sheath, the grout material remaining between the sheath and the trumpet tube, and the pipe part of the trumpet tube can reliably prevent corrosion of the tensile material, and the structure has excellent workability, safety, and durability of the structure, It has extremely useful effects in practice, such as being able to construct a ground anchor in the construction method and work process.
[Brief description of the drawings]
FIGS. 1A to 1H are schematic sectional views showing an example of an embodiment of a ground anchor construction using a trumpet pipe according to the present invention.
FIG. 2 shows an example of an embodiment of a trumpet pipe for ground anchor work according to the present invention, in which (a) is a longitudinal sectional view and (b) is a perspective view of an enlarged diameter portion.
FIG. 3 is a schematic cross-sectional view showing an example of a usage state of a trumpet tube.
FIG. 4 is a schematic sectional view showing an example of an embodiment of an anchor structure constructed by ground anchor work using a trumpet pipe according to the present invention.
FIGS. 5A to 5E are schematic cross-sectional views showing an example of a conventional ground anchor method.
[Explanation of symbols]
G Grout material 1 Trumpet tube 2 Pipe portion 3 Expanded portion 4 Guide pin 5 Trumpet tube stopper sheath 6 Casing pipe 7 Tendon 8 Coupling 9 Anchor body

Claims (4)

  In ground anchor work, grout material is press-fitted into a casing pipe to form an anchor body in the base, and then a pipe portion having a diameter between the tensile material and a tip portion of the pipe portion is provided and communicated therewith. A trumpet pipe formed by the enlarged diameter portion is inserted into the casing pipe, and the grout material between the casing pipe and the trumpet pipe is discharged through the pipe section of the trumpet pipe. Ground anchor construction using a trumpet pipe.   In ground anchor work, after grout material is press-fitted into a casing pipe and an anchor body is formed in the base, it is inserted into the casing pipe, and a pipe portion having a diameter having a gap between the tensile material and A trumpet pipe for ground anchor construction, characterized in that it is formed by a diameter-expanded portion provided at the tip portion of the pipe portion and communicating therewith. The tread pipe for ground anchor construction according to claim 2 , wherein the enlarged diameter portion is provided with a guide member on the tip side.   In the ground anchor work, a grout material is press-fitted into a casing pipe to form an anchor body in the base, and then inserted into the casing pipe, a pipe portion having a diameter between the tensile material and the pipe portion. A trumpet tube stopper sheath which is attached to the end of a pipe portion of a trumpet tube which is provided at a distal end portion and communicates with the enlarged diameter portion, and whose main body is constituted by a bellows body.

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