JPS6340016A - Earth anchoring work - Google Patents

Abstract

PURPOSE:To raise the bearing force of anchors by a method in which a reaction body with faces crossing with the action line of a tensile force is fixed to a tension member, and the tension member is penetrated into an anchor hole and fixed by a tension force to the natural ground by the injection of grout. CONSTITUTION:Reaction bodies 1 of a lantern type hollow cylinder form are fixed to a tension member 2, e.g., PC steel wire, etc., and a compression face 11 and a lower face 12, which are not in parallel with the acting line of tension to be applied to the tension member 2, are provided for the outer face of the body 1. A through hole 13 for the member 2 and a through hole 14 for a grout- injection hose are formed in the upside and downside of the body 1. The member 2 is inserted into the anchor pit 4 being excavated, a grout 3 is injected into the pit 4, and a grout 6 is injected into the sheath 21 and the body 1. After the curing period of the grouts, the end of the member 2 is tensed to introduce a given tension P into it and an anchor head 5 is attached to the member 2 for fixation. The bearing force of anchor can thus be exactly calculated.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an earth anchor construction method.

<Prior Art> In general, the yield strength of an earth anchor is determined by the adhesion force between the tensile material fixed in the ground and the anchor grout, and the adhesion force between the anchor grout and other heaps.

By the way, FIG. 5 shows a general earth anchor.

This earth anchor has a structure in which a tensile material is inserted into an anchor hole a, and then fixing grout e is injected into the anchor hole a to fix the tensile material to another thread.

Thereafter, the base end of the tensile material is tensioned to apply a predetermined tensile force P to fix it.

<Problems to be Solved by the Present Invention> The conventional earth anchor construction method described above has the following problems.

The yield strength of a conventional earth anchor is determined by two resistance forces: the frictional resistance force P between the tensile material and the anchoring grout C, and the frictional resistance force P2 between the anchoring grout C and the ground.

However, if the tensile force P introduced into the tensile material is very large, friction breakage is likely to occur because the contact surface resistance of the frictional resistance force P1 is relatively small.

As a result, if friction breaks occur in the tensile material, it will no longer have the strength needed to serve as an anchor.

As mentioned above, in order to prevent the tensile material from breaking due to friction, it is necessary to accurately calculate the proof stress of the anchor in advance.

However, in the conventional earth anchor construction method, it is extremely difficult to accurately determine the strength of the anchor through mechanical calculations.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an earth anchor construction method that can improve the proof strength of an anchor and accurately calculate the proof strength of the anchor.

Configuration of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

First, the main components used in this construction method will be explained.

〉Reaction force body (Fig. 1.2) The reaction force body 1 is fixed in the middle of the tensile material 2 such as PCM wire,
This is a member that functions as a reaction force resistor between the fixing grout 3 and the fixing grout 3.

An example of the reaction force body 1 is shown in FIG.

This reaction force body 1 consists of a hollow cylindrical body in the shape of a lantern, and its outer surface has a compression surface 11 that is not parallel to the line of action of the tensile force acting on the tensile member 2, and a lower surface 12.

A through hole 13 for penetrating the tension member 2 and an insertion hole 14 for inserting a grout injection hose are formed on the upper and lower surfaces of the reaction body 1, respectively.

As will be described later, the reaction force body 1 can be made of metal, resin, or the like, as long as it is filled with grout and formed as a rigid body.

[Reaction force body fixing means 1 To fix the reaction force body 1 in the middle of the tension member 2, for example, as shown in FIG. Possible methods include a method of fixing the reaction force body 1, or a method of fixing the reaction force body 1 by driving wedges into both ends thereof.

Construction method (Figure 1) The following is a step-by-step explanation.

(1) Assembling tensile material The reaction force body 1 is fixed in the middle of the tensile member 2.

The tensile member 2 between the reaction force members 1 is covered with a sheath 21 .

In this case, the short sheath 21 and the reaction force body 1 are assembled by passing through the tension member 2 alternately.

As for the assembly method, the ends of the reaction force body 1 and the sheath 21 are screwed together or bonded together, and the reaction force body 1 and the sheath 21 are arranged alternately.

The mounting position and number of reaction force members 1 are determined by taking into account the properties of the ground, the tensile force to be introduced, and the like.

(2) Insert the assembled tensile material 2 into the anchor hole 4 after insertion of the tensile material and injection of grout.

Next, the anchoring grout 3 is injected into the anchor hole 4, and the anchoring grout 6 is injected into the sheath 21 and the reaction body 1.

When injecting the fixed grout 6 into the sheath 21 and the reaction force body 1, a hose for grout injection is passed through the tube of the sheath 21 and each reaction force body 1, and inserted to the tip of the anchor.
This is done by sequentially injecting the fixed grout 6 from the tip to the base.

(3) Tensioning and fixing After a predetermined curing period has elapsed, the end portion of the tensile material 2 exposed from the anchor hole 4 is tensioned to introduce a predetermined tensile force P.

Further, an anchor head 5 is attached to the above-mentioned end portion of the tensile material 2 and fixed thereto.

(kuha) Improving the strength of the anchor (Fig. 1.3) As shown in Fig. 3, the compression surface 11 of the reaction force body 1 is inclined at an angle θ with respect to the line of action of the tensile force P. The tensile force P is divided into vectors Pl, P2, and P in a direction perpendicular to the compression surface 11.

Each of the divided force vectors P1, P2, and P3 acts on the fixing grout 3 and the ground as a compressive force.

Therefore, I! between the fixed grout 3 and the ground! J Increases friction resistance.

Furthermore, when the tensile force P acts on the tensile member 2, the fixed grout 6 inside the reaction force body 1 is compressed, and the force changes to grip the tensile member 2, and the fixing force between the reaction force body 1 and the tensile member 2 is reduced. increase

From the above, it is possible to obtain greater reaction force and stability compared to conventional anchor mechanisms, thereby improving the strength of the anchor.

<2> Control of tensile force (Figure 3) As mentioned above, it is possible to divide the tensile force P into multiple vectors, so the tensile force P can be determined by determining each divided vector. Can be done.

Therefore, by selecting the angle θ of the compression surface 11 of the reaction force body 1, the direction of the generated vector can be controlled, and therefore the direction of the reaction force of the tensile force P can also be controlled.

Similarly, the magnitude of the vector generated on each compression surface 11 can be calculated from the number of reaction force members 1 installed and the angle θ of the compression surface 11, and the magnitude of the tensile force P can be easily calculated as Pl.

Other Embodiments (FIG. 4) In the above embodiment, the sheath 21 is attached to the outer periphery of the second group of tension members.

As another embodiment, instead of attaching the sheath 21 to the outer periphery of the two groups of tension members, each tension member 2 in the anchorage length portion of the anchor is covered with a covering material 7 such as polyethylene on the ground, It is conceivable to protect the material 2.

Further, each tension member 2 in the free length portion L2 of the anchor is covered with an unbonded material 8 without adhering to the tension member 2 to protect the tension member 2 so as not to prevent the tension member 2 from stretching. It is possible that

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

B) By attaching a reaction force having a compression surface that is not parallel to the line of action of the tensile force to the tensile material, the tensile force is a reaction of a vector in a direction perpendicular to the compression surface of the reaction force. converted into power.

Therefore, each transformed vector acts as a compressive force on the anchor grout and the rock, increasing the frictional resistance between the anchor grout and the rock.

In addition, when a tensile force acts on the tension member, the fixed grout injected into the reaction body is compressed and turns into a force that grips the tension member, increasing the anchoring force between the reaction body and the tension member. .

Therefore, from the above, compared to the conventional anchor mechanism,
Large reaction force and stability can be obtained, and the strength of the anchor can be improved.

<mouth> As described above, the tensile force introduced into the tensile member can be converted into a reaction force in a vector in a direction perpendicular to the compression surface of the reaction force body.

Therefore, by selecting the angle that the compression surface of the reaction body forms with the line of action of the tensile force, the direction of the generated vector can be controlled, so the direction of the reaction force of the introduced tensile force can be freely adjusted. can be controlled.

Similarly, from the number of reaction bodies installed and the angle that the compression surface of the reaction body makes with the line of action of the tensile force, find the magnitude of the vector generated in the reaction body, and easily calculate the magnitude of the tensile force. It can be calculated as follows.

From these facts, it becomes possible to dynamically calculate the proof strength of the anchor, and the proof strength of the anchor can be determined accurately.

[Brief explanation of drawings]

Fig. 1 2 An explanatory diagram of one embodiment of the present invention Fig. 2: An explanatory diagram of the reaction force body Fig. 3: An explanatory diagram showing the action of the reaction force body Fig. 4: An explanatory diagram of another embodiment Fig. 5 :Explanatory diagram of conventional earth anchor method Applicant
Taisei Corporation Figure 1 Figure 49 1

Claims (1)

[Claims] A resistor having a surface not parallel to the line of action of the tensile force is fixed in the middle of the tension member, the tension member is inserted into the anchor hole, and fixing grout is injected into the anchor hole. An earth anchor construction method in which the material is fixed to the ground and fixed by applying a predetermined tension to the tensile material.