JPS61117400A - Locking anchor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention involves drilling a hole in rock, inserting a chain, wire, steel rod, etc. into the hole, and pouring cement milk between the chain, wire, steel rod, etc. and the rock. This relates to a type of rock anchor that is injected and hardened.

FIG. 1 shows a longitudinal sectional view of a conventional lock anchor. 11
is rock, 2+ is tension material such as chain, wire, steel rod, etc., 5
' is solidified cement milk injected between the rock and the anchor, and 41 is an anchor head for preventing the anchor from being pulled out. To construct this anchor, drill a hole in the bedrock 1, insert tendons into the hole, inject cement milk between the tendons and the bedrock, and cure for a certain period of time.The cement milk will harden. tb, tension material 2
1 and the bedrock 1 resist the tensile force P' as one body. When the anchor is pulled by external force P1, a shear stress is generated between the tendon and the cement milk, and the cement milk generates a tensile stress. As is well known, cement milk is resistant to tensile stress just like concrete.

Prone to cracking. With this kind of anchor.

It is known that cracks can occur even under a load that is less than the design load because the cement milk is directly stretched, and water, air, etc. can enter through these cracks, causing the tendons to rust and break. arise. In particular, tendons are constantly stretched and subject to relatively large stress, so they are susceptible to rust.

For this reason, corrosion protection of tendons is very important.

Furthermore, in the type shown in Fig. 1, the length of the tendon is determined by the adhesive force between the tendon and cement milk, so the length of the tendon inevitably becomes long.

The present invention was invented for the purpose of canceling the tensile stress of cement milk caused by the tensile force of tendons and providing an anchor system that does not cause cracks and is excellent in rust prevention.

The present invention provides an anchor body which is formed integrally with a tension material having a cable locking part and a cylinder body which is prestressed by the tension material penetrating the inside of the tension material, and which is pre-drilled into the rock. This relates to a rock anchor that is inserted into a hole and then solidified with cement milk to form an integral part of the rock.

(Conventionally, a part of the Cemecyto Milk, which had been constructed on-site, was precast. This precast part was given prestress. (2) The above stress was removed.

It cancels the tensile stress caused by external force, prevents cracks in the cement milk, and (3) provides an anchor system with excellent rust prevention compared to (2). + (') Because a part of the cement milk is precast. The aim is to provide an economical rock anchor that can increase the attachment area and shorten the length of the anchor, and can be applied to 2-port facilities, 8BM, water intake facilities, plant barges, etc.

An embodiment of the lock anchor of the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic vertical sectional view of one embodiment of the lock anchor of the present invention.

FIG. 3 shows a schematic view of a cylinder made of cement milk, cement mortar, or concrete that forms part of the rock anchor of the present invention. 1 is rock, 2 is a tension material such as a chain, wire, or steel rod with a mooring rope locking part, and 5 is cement milk.

5 is cement milk or cement mortar, 6 is a concrete cylinder, 6 is a fixing device such as a nut, and 7 is grout (something with high elongation ability).

8 indicates a washer, and 9 indicates a high-strength grout. In FIG. 3, tendons 2. Cylindrical body 5. The structure consisting of a nut 6, grout 7, and washer 8 is called an anchor body here. The anchor body is produced in a secondary manner. First, a cylindrical body 5 as shown in Fig. 2 is made, and one (lower) fixing device 6 is attached through the washer 8 through the tension material 2.Next, the tension material 2 is attached with the design load of the lock anchor. It is pulled using a jack or the like, and the other (upper) fixing tool 6 is attached via the washer 8.

In this way, the soot and dirt are removed from the cylindrical body 5.

The tension of the tendon material 2 constantly generates compressive stress. Thus, tendons 2. Fixing tool6. After installing washer 8, grout 7'.

Apply 9. In this way, the cylindrical body 5 is given a sive stress by the tension material 2. After inserting a rock anchor consisting of a fixing device 6 and a washer 8 for fixing the anchor, and grout 7.9 enclosing these into a hole previously drilled in the rock mass, the rock anchor is inserted between the rock mass 1 and the main anchor body. is filled with cement milk in the same way as in the conventional Figure 1. Note that the tension material 2 is located between the tendon material 2 at the part 10 in Fig. 2 and the cement milk.
Apply grease or the like to prevent the pull-out force P from being transmitted.

The operation of the present invention will be explained.

(As mentioned above, the cylinder 5 is compressed under the design load. Therefore, even if it is pulled under the design load, no tensile stress is generated in the cylinder 5.

(2) Tensile material inside the anchor body 2. The fixing device 6, washer 8, etc. are sealed with grout 7.

(3) The pull-out force P of the tendon 2 is high strength grout 9
and fixing device6. Cement milk is transmitted to the cylinder 5 via the washer 8, and further from the cylinder 5. It is further transmitted to Bedrock 1.

(4) Since the grout 7 is made of an elastic sealant or the like with a high elongation ability, it will not come off due to the elongation K of the anchor 2.

The present invention achieves the following 91-order effects in addition to the above configuration.

(1) Since a compressive force is applied to the cylindrical body 5 in advance, no cracks will occur even if the tension material 2 is pulled.

(2) Tension material 2. Fixing tool6. Since the washer 8 and the like are completely sealed, they will not rust.

(3) Since the surface area (adhesion area) of the cylinder 5 is larger than the surface area of the tendon material 2 itself, the length of the anchor can be made shorter than that of the conventional one shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional rock anchor. FIG. 2 is a schematic longitudinal sectional view of an embodiment of the rock anchor of the present invention, and FIG. 3 is a schematic diagram of a cylinder made of cement milk, cement mortar, or concrete that forms a part of the rock anchor of the present invention. . 2... Tension material provided with a rope locking portion, 5... Cylindrical body. 3...Cement milk, 1...Bedrock. Sai 2nd Ward

Claims (1)

[Claims] An anchor body, which is integrally formed with a tension member equipped with a rope locking portion and a cylindrical body which is prestressed by the tension member penetrating the inside, is inserted into a hole previously drilled in the rock. A rock anchor that is inserted and solidified with cement milk to form an integral part of the bedrock.