JP7449789B2 - How to stop water using the removable anchor method, how to remove strands using the removable anchor method - Google Patents

Description

The present invention relates to a removable anchor construction method that uses a mechanism in which a strand (unbonded PC steel strand) bent back into a loop shape is combined with a load-bearing body, and the method of construction uses a mechanism that combines a strand (unbonded PC steel strand) bent back into a loop shape with a load-bearing body. This relates to a method for pulling out and removing strands.

FIG. 3 is a sectional view showing an example of construction using the removable anchor construction method.
FIG. 4 is a process diagram showing the working procedure of the removable anchor construction method shown in FIG. 3.
The removable anchor method is used to absorb the reaction force of retaining walls that occur when constructing buildings in urban areas. As shown in Figure 3, the removable anchor method uses unbonded PC steel strands 83. This unbonded PC steel stranded wire 83 is constructed by encasing a strand 85 in a sheath 87 made of polyethylene or the like, and filling the gap with grease 89.

The removable anchor construction method applies a reaction force to a structure such as a dam by tensioning a strand 85 as shown in FIG. 4(a) after the grout hardens. After the construction of the heap retainer etc. is completed, as shown in FIG. 4(b), the strands that become underground obstacles are gas cut to release the load, and then the pedestal is removed as shown in FIG. 4(c). Then, as shown in FIG. 4(d), the strand 85 can be easily pulled out and removed from the sheath 87 using a crane truck, tow truck, hydraulic jack, or the like.

As mentioned above, the strand 85 that becomes an underground obstacle can be pulled out, but since the sheath 87 remains underground after the strand is pulled out, if this sheath 87 is damaged, the inside of the sheath 87 will be damaged as shown in FIG. There is a concern that groundwater (free water/pressurized water) may enter the anchor and cause water to spring out from the mouth (anchor head). Therefore, as shown in FIGS. 4(e) and 4(f), it is necessary to attach a water-stopping device or the like to the mouth part or inject a water-stopping material.

Furthermore, immediately after the strand 85 is pulled out by a crane vehicle or the like, the strand 85 wraps around or jumps up as shown in FIG. 6, which is very dangerous, and safety measures are required for the behavior of the strand 85. Furthermore, at this time, the grease filled in the sheath 87 also scatters, so it is necessary to protect surrounding structures from the scattering of the grease and clean up the scattered objects.

Therefore, in view of the problems of the prior art described above, an object of the present invention is to provide a method that can prevent water from gushing out from inside the sheath when the strand is pulled out in a removable anchor construction method. Another object of the present invention is to provide a method in which strands can be pulled out efficiently and with high safety in a removable anchor construction method.

In order to solve the above problems, the method according to the present invention includes the following features.
(1) As shown in FIG. 1, a rope 21 coated with a waterproof material having the same diameter as the sheath inner diameter is connected to the other end of the strand 5 bent back into a loop shape from the pull-out side. This rope 21 is inserted into the sheath 7 at the same time as the strand 5 is pulled out. As a result, a water stop body is formed within the sheath 7, and even if the sheath 7 is damaged, it is possible to prevent underground water from flooding.
(2) As shown in FIG. 2, since the rope 21 is connected to the end of the strand 5, it is possible to prevent the strand 5 from winding around or jumping up immediately after being pulled out.

In other words, the above-mentioned purpose is to connect a rope-shaped water-stopping means to the end of the strand that is bent back into a loop, which is different from the end on the pull-out side, when the strand is removed from the sheath in the removable anchor method. This is accomplished by pulling out the strand so that the rope-like water stop means is inserted into the sheath at the same time as the strand is pulled out. The rope-shaped water-stopping means used in this method is comprised of a rope coated with a water-stopping material and has approximately the same diameter as the inner diameter of the sheath.

According to the present invention, when the strand is pulled out, the strand and the rope coated with a water stop material (rope-like water stop means) are replaced, so even if the sheath is damaged, water will flow into the damaged sheath. It is possible to block groundwater. Therefore, there is no need to perform water stop treatment at the mouth part, install a water stop device, etc., or inject water stop material after pulling out the strand, as shown in Figures 4(e) and 4(f), simplifying the construction process and shortening the process. , construction costs can be reduced.

Further, according to the present invention, the rope coated with the waterproof material is automatically dragged into the sheath in conjunction with the pulling operation of the strand. Therefore, there is no need to take the trouble to insert the rope after the strand is pulled out, so the above-mentioned simplification of construction and shortening of the process is not hindered.

Furthermore, according to the present invention, the rope inserted into the sheath is connected to the rear end of the strand, providing resistance to the strand being pulled out. That is, as shown in FIG. 2, the rope connected to the rear end of the strand immediately after being pulled out restricts the movement of the strand. Therefore, it is possible to prevent the strand from winding or jumping up immediately after being pulled out, and from scattering the grease attached to the strand, eliminating the need for scattering curing, etc., and improving workability and safety during pulling.

Further, according to the present invention, it is possible to visually confirm that there is no remaining strand material by inserting the rope (replacing it with a strand), thereby improving reliability of quality.

1 is a sectional view illustrating an embodiment of a method according to the invention; FIG. 1 is a sectional view illustrating an embodiment of a method according to the invention; FIG. It is a sectional view showing a construction example of a removable anchor construction method. It is a process diagram showing the work procedure of the conventional removable anchor construction method. It is a figure showing the problem of the conventional removable anchor construction method. It is a figure showing the problem of the conventional removable anchor construction method.

Embodiments of the present invention will be described below based on FIGS. 1 and 2.

In the removable anchor method, unbonded PC steel strands 3 are used as the anchor cable (tension support material). As shown in FIG. 1, the unbonded PC steel stranded wire 3 is constructed by encasing a strand 5 (PC steel strand) in a sheath 7 made of polyethylene or the like, and filling the gap with grease 9.

When constructing the removable anchor method, first attach the unbonded PC steel wire 3 bent back into a loop shape to the tip of the load-bearing body 11, and then combine the unbonded PC steel wire 3 and the load-bearing body 11. The mechanism is inserted into an anchor hole drilled in the ground, and both ends of the strand 5 are passed through the retaining plate and pulled out to the outside of the ground. Next, the anchor hole is filled with grout material, and after hardening, the reaction force is taken by the earth retaining wall, and both ends of the strand 5 are pulled with a jack to tighten and fix the grout material, thereby performing earth retaining.

After completing the construction of the heap, etc., the strand 5 is pulled out from one end side of the strand 5 pulled out to the ground surface and removed from the sheath 7. When removing the strand 5 from the sheath 7, the strand 5 is first gas-cut to release the load as in the prior art, and then the pedestal is removed. See FIGS. 4(b) and 4(c).

Next, a rope 21 having approximately the same diameter as the inner diameter of the sheath 7 and coated with a water-stopping material is attached to the end (rear end) of the strand 5 bent back into a loop shape, which is different from the pull-out end (tip). (rope-shaped water stop means). Hereinafter, the rope coated with a water-stop material will be abbreviated as a "water-stop rope." By connecting the water stop rope 21 to the rear end of the strand 5, a state in which the water stop rope 21 is connected to the rear end of the strand 5 and is unified is ensured.

The water-stopping material applied to the rope is not particularly limited as long as it has a water-stopping effect, and specific examples include water-stopping materials based on epoxy or urethane resins and underwater curing materials. Examples include fillers. This material expands when it reacts with water underground, filling voids and then hardening. Materials called filler adhesives, underwater curing agents, wet surface curing materials, etc. are included in the water stop materials that can be used in the present invention.

Subsequently, the end of the strand 5 on the pulling side is connected to a pulling device such as a crane truck or a tow truck via a connector or a hook. In the illustrated embodiment, a crane truck is used as an example of the extraction device.

Next, the strand 5 is pulled out so that the water stop rope 21 is inserted into the sheath 7 at the same time as the strand 5 is pulled out. As mentioned above, the water stop rope 21 is connected to and integrated with the rear end of the strand 5, so when the strand 5 is pulled out of the ground, the water stop rope 21 is simultaneously inserted into the sheath 7 (the trace of the strand being pulled out). I get dragged into it. Therefore, if the strand 5 is continued to be pulled out of the ground, the strand 5 inside the sheath 7 will be replaced by the water stop rope 21.

During the process of pulling out the strand, the water-stopping rope 21 is connected to the rear end of the strand 5, which acts as a resistance to pulling out the strand. As shown in FIG. 2, the water stop rope 21 connected to the rear end of the strand 5 immediately after being pulled out restricts the movement of the strand. Therefore, it is possible to prevent the strand 5 from winding or jumping up immediately after being pulled out, and from scattering the grease attached to the strand 5, eliminating the need for scattering curing, etc., and improving workability and safety during pulling out.

Finally, when the behavior of the strand 5 pulled out from the sheath 7 has stabilized, the water stop rope 21 is cut off from the pulled out strand 5.

3 Unbonded PC steel stranded wire (anchor cable/tension support material)
5 Strand (PC steel stranded wire)
7 Sheath 9 Grease 11 Load-bearing body 21 Rope coated with water stop material (water stop rope/rope-like water stop means)
83 Unbonded PC steel stranded wire 85 Strand 87 Sheath 89 Grease

Claims (3)

When removing the strand from the sheath in the removable anchor method,
A rope-shaped water stop means is connected to the end of the strand bent back into a loop, which is different from the end on the pull-out side.
A water stop method using a removable anchor method, characterized in that the strand is pulled out so that the rope-like water stop means is inserted into the sheath at the same time as the strand is pulled out. When removing the strand from the sheath in the removable anchor method,
A rope-shaped water stop means is connected to the end of the strand bent back into a loop, which is different from the end on the pull-out side.
A method for removing a strand in a removable anchor construction method, characterized in that the strand is pulled out so that the rope-shaped water stop means is inserted into a sheath at the same time as the strand is pulled out. 3. The method according to claim 1, wherein the rope-shaped water stop means is comprised of a rope having approximately the same diameter as the inner diameter of the sheath and coated with a water stop material.