What is the unit weight of 25 combined hollow anchors for tunnels

7kg。The hollow composite bolt is made of a 50 cm hollow rod body and two or three meters of solid rebar.

The rod body is combined, and the weight calculation formula of the hollow anchor rod body is: (outer diameter - wall thickness) * wall thickness *, and the weight calculation formula of the solid rebar rod body is: diameter * diameter = kg m.

For example, 22 25*4mm*weight of hollow part = (25-4)*4*, weight of solid part =, total weight = 7kg.

Hollow bolt is a kind of hollow bolt, which is more used in resin, stable and intact rock layer, cement and engineering glue, which is a more stable bolt than ordinary anchor. The anchor rod is generally composed of a free section and an anchor section, and the anchor body of the hollow anchor rod is a hollow design.

Our company is specialized in the production of hollow bolts. We generally use the following formula to calculate the weight of the bolt:

Weight = (outer diameter - wall thickness) * wall thickness *, the unit of outer diameter wall thickness is cm. The unit of calculated weight is kg.

TB T 3209-2008 "Technical Conditions for Hollow Anchors" stipulates:

25 combined hollow anchors, composed of 25 steel bars + 32 hollow anchor segments.

Rebar (grade HRB335 length can be customized).

Bolt section (50 cm fixed length).

Combined together (1m steel bar + bolt section) is: meters.

Schematic diagram of four types of bolts.

What is the unit weight of 25 combined hollow anchors for tunnels

Hello, your problem teacher will help you inquire as follows: The hollow combined bolt is generally composed of a 50 cm hollow rod body and a two-meter or three-meter solid screw with a swarf steel rod body. Formula for calculating the weight of hollow bolt rod body:

Outer diameter Na Na - wall thickness) * wall thickness *; The formula for calculating the weight of the solid rebar rod is as follows: diameter * diameter = kg mFor example, 22 25*4mm*weight of hollow part = (25-4)*4*weight of solid part = total weight = 7kg, I hope the teacher's reply can help you I wish you a happy life Thank you!

What is the unit weight of 25 combined hollow anchors for tunnels

Dear, hello, I'm glad to answer for you, what is the weight of Minshan in the 25 combined hollow bolt unit for tunnels? Answer: The diameter of the hollow bolt refers to the outer diameter, you can calculate it according to the steel density of 7850kg m3, according to different wall thicknesses.

Commonly used 25*5 is. You can also check the specification "Zhongqiao only hollow grouting bolt implementation standard TBT 3209-2008", which has a variety of different bolt weights and allowable deviations.

At this stage, how do construction companies carry out tunnel hollow bolt construction, and what is the basic situation? The following is the relevant content of Zhongda Consulting's professional construction terminology for tunnel hollow bolt construction, and the basic situation is as follows:

Precautions for the construction of hollow anchors in tunnels:

1) For the grouting of hollow anchors, Songbi supervision should have a side station record, and it is strictly forbidden to do not grouting behavior.

2) The hollow grouting bolt should be kept hollow and smooth during construction, and a special exhaust hole should be left. The nut should be tightened after the initial setting of the mortar, and the backing plate should be in close contact with the shotcrete surface.

3) The hollow grouting anchor rod should have anchor heads, backing plates, nuts, slurry stoppers and other Qingying virtual accessories.

4) During the grouting process, the grouting pressure should be kept at about the left and right, and the grouting can be stopped only after the exhaust port is grunted.

Safety requirements and measures for the construction of hollow anchors in tunnels:

1. During the construction period, the working status of the support should be checked regularly and irregularly. In a bad geological area? It should be inspected by a special person on each shift.

2. When the construction is suspended, the support should be directly reached to the excavation face.

3. The simple bench of the anchor rod should be placed safely.

4. If the wind, water and conveying pipelines are blocked or burst during the operation, the transportation of wind, water and materials must be stopped in turn.

5. Remedial measures should be taken when the deformation and cracking of the support system are found in the monitoring and measurement of the bolt support system. When the danger is critical, personnel should be evacuated from the danger zone.

6. If there is a large deformation or failure of the anchor rod in the anchored lot, immediately add a reinforced anchor rod in the lot, and the length shall not be less than the length of the original anchor rod.