How to calculate the anchor force

1. The calculation of anchoring force is very complex, and the existing formulas have limitations. We should consider the surrounding rock loose circle, the key layer and other factors, the key is the field situation and the use of nature.

2. 1. The formula for calculating the torsional moment of the threaded steel bolt is t = MDK, where t is the torsional moment; M - pre tightening force; D-diameter; K - coefficient. about φ For 22 rebar, k = 0.39
2. The corresponding maximum torque is 80KN × 22mm × 0.39=686.4N·m

3. The pull-out force of the bolt is generally calculated according to the cross-sectional area of the bolt and the allowable tensile stress of the bolt material. As for the length of the anchor, it must be carried out according to the regulations. Otherwise, the diameter of the anchor hole is larger, the depth is not enough, and the bolt is pulled out, which can not play the role of anchoring. It is absolutely not allowed
according to the calibration value on the calibration certificate of anchor tension meter or Jack, the oil pressure (MPA) is converted into pressure (KN) by interpolation method, and different instruments are used

4. The bearing capacity of the anchorage section is the bearing capacity of the anchor rod, and the minimum values of the tensile strength of the anchor rod, the bond strength between the rod and the anchorage mortar, and the bond strength between the anchor solid and the soil layer are taken

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5. Generally, the design value of pull-out bolt will exceed the actual stress value of bolt about 5 ~ 10 times···

6. Anchor rod has no pull-out force, only anchoring force. The anchoring force is 1.2 times of the yield load.

7. The pull-out force of the bolt is generally calculated according to the cross-sectional area of the bolt and the allowable tensile stress of the bolt material. As for the length of the anchor, it must be carried out according to the regulations. Otherwise, the diameter of the anchor hole is larger, the depth is not enough, and the bolt is pulled out, which can not play the role of anchoring. It is absolutely not allowed!

8. Calculate the pull-out force of anchor

9. The pull-out force is 1.3 times of the yield force

10.

Nak = HTK / cosa, Na = RQ * NAK

NK - standard value of axial tension of anchor rod (KN), FH - horizontal reaction of elastic fulcrum within the calculated width of retaining member (KN), s - horizontal spacing of anchor rod (m), Ba - calculated width of structure (m), and, α -- inclination angle of anchor rod °)

according to the designed anchoring force, the cross-sectional area of anchor rod a: a = (k) is determined × N) / FTK, FTK is the standard value of tensile strength of pull rod
in the design, there are also some bolts (such as improving the shear strength parameters of sliding surface, such as toe slab foundation bolts) which are set according to the experience requirements. Generally, the bolt size, anchor length and other parameters have been determined first, and the design anchor force (pull-out force) of the bolts has also been proposed according to the above steps 1 and 2

extended data:

precautions:

1. When using the equipment, it is necessary to carefully read the technical instructions, be familiar with the technical indicators, working performance, use methods and precautions, and strictly follow the proceres specified in the instrument instructions

The instruments and equipment used in the experiment should be arranged reasonably, placed neatly, easy to operate, observe and record

When using the equipment, its input signal or external load should be limited within the specified range, and overload operation is prohibited

It should be handled with care to prevent vibration. When st and dirt are found, it is not allowed to wipe it with hands or cloth. It must be removed with special procts or special tools

The equipment should not be used in magnetic field or electric field, and shielding measures must be taken to prevent the equipment from damage or rece the measurement accuracy