A tension-compression type prestressed anchor cable anchoring end device

Abstract

The invention discloses an anchor end device of a tension-compression pre-stressed anchor cable. The anchor end device of the tension-compression pre-stressed anchor cable mainly comprises an expansion shell inside wedge, an expansion piece, an extrusion body, a circular tightening ring, an extrusion nut, an expanding sleeve and a welding circular ring, a through hole through which a steel strand passes and a grouting hole are formed in the middle of the expansion shell inside wedge, the steel strand at the upper end of the expansion shell inside wedge near the expanding sleeve is firmly connected with the expansion shell inside wedge, embedded holes in which extrusion bodies are embedded are uniformly distributed in the edge of the expansion shell inside wedge, the expansion piece closely surrounds the expansion shell inside wedge, the lower end is connected with the welding circular ring, the circular tightening ring for fixing the expansion piece is arranged at the middle of the expansion shell inside wedge, the expansion piece is provided with the extrusion nut near the lower part, and the extrusion nut is connected with the steel strand. According to the anchor end device of the tension-compression pre-stressed anchor cable, the stress distribution on the anchor end is more uniform and reasonable, the design intensity of the pre-stressed anchor cable is improved, and the break (crack) degree of the grouting at the part in contact with a supporting body is alleviated; the anchor end device of the tension-compression pre-stressed anchor cable can be broadly used for the long-term or temporary strengthening for side slopes, foundation ditches and the like.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering prestressed anchor cable anchoring, and in particular relates to a tension-compression type prestressed anchor cable anchoring end device. Background technique [0002] The tension-compression prestressed anchor cable is a composite anchoring form based on the tension type and the pressure type. It has the characteristics of the tension type and the pressure type at the same time, so that the grouting body is simultaneously affected by the tension stress and the compression stress. , which improves the design strength of the anchor cable. The tension-compression prestressed anchor cable is generally composed of three parts: the inner anchor head, the anchor cable body and the outer anchor head. It has many advantages such as large anchorage depth, high bearing capacity, and large prestress can be applied. The stress state of the structure can effectively control the deformation a...

AI Technical Summary

Problems solved by technology

[0003] Although tension-compression prestressed anchor cables have been widely used in practice, due to their immature technology, potential problems in actual construction are still very serious, such as the stress distribution of each steel strand when multiple anchor cables work for a long time Unevenness causes individual steel strands to be broken due to excessive stress, which leads to the consequences of being broken. The steel strands exposed in the tensile stress section in the long-term reinforcement have the problem of being corroded, due to the uneven distribution of tension and compression stress. uniform so that the contact surface between the inner anchor carrier and the grouting body is still easy to be crushed or the contact between the steel strand and the grouting body is easy to be pulled, etc.

[0004] At present, most of the tension-compression prestressed anchor cables are mechanically embedded in the grouting body, relying on the limited contact surface between the grouting body and the carrier body to generate pressure on the grouting body to provide compressive stress, and the carrier body and The contact of the grouting body is prone to stress concentration, which will damage the grouting body at the contact point. The rigid contact between the grouting body and the carrier also makes the breakage easier to occur, and this damage will continue to extend over time, so that the grouting body The crushing of the slurry leads to the loss of the prestress of the anchor cable. In severe cases, the entire bearing body will be gradually pulled out. It is not economically cost-effective to increase the stress area of ​​the grouting body by blindly expanding the diameter of the borehole.

The bonding force between the grouting body and the steel strand does not actually provide too much tensile stress, and there will be serious concentration of tensile stress at the beginning of the bond, so the grouting body is easy to The loss of the prestress of the anchor cable caused by the damage of the tensile crack, the broken anchor cable will extend to a certain depth when the tension of the anchor cable is too large, this kind of broken will affect the overall stability of the grouting body, and then make the grouting body easier to withstand high pressure Under the action, it is crushed by the bearing body. In addition, the direct contact between the exposed steel strand and the grouting body also makes the tension-compression prestressed anchor cable have a safety hazard of steel strand corrosion and being pulled off.

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