A detection method and device for the rust and expansion of shallow reinforcement in tunnel lining

Abstract

A method and device for detecting the rust and expansion of steel bars in shallow layers of tunnel lining. When there is rust and swelling of steel bars on the surface or shallow part of the tunnel lining, the potential rust and swelling of steel bars can be located and the degree of rust and swelling of steel bars can be judged according to the temperature difference. After the steel bar rusts and swells, it will cause rust cracks on the corresponding lining surface, which are cracks along the reinforcement. By obtaining the position distribution of the cracks on the lining surface along the reinforcement, it can assist in locating the rusted and swollen parts of the steel bar; the stiffness of the corresponding area will also decrease after the steel bar is swollen The deformation of the structural surface is obviously different from that of the complete parts on both sides, and the crack width and deformation of the lining surface will be different with different reinforcement rust expansion degrees. Therefore, based on the relationship between the reinforcement rust expansion and the lining surface deformation and crack width Combined with the relationship of temperature changes in the infrared thermal image, the location of the rust and swelling of the steel bar can be determined, and the degree of rust and swelling of the steel bar can be judged.

Description

technical field [0001] The invention relates to the technical field of tunnel defect detection. Background technique [0002] Under the influence of chloride ion erosion, concrete carbonation, stray current, etc., the tunnel in the water-rich environment or sea environment will corrode the steel bars inside the tunnel lining. cracks, which aggravated the corrosion of steel bars, and finally caused serious cracks on the lining surface, peeling off, water leakage and other diseases, which seriously affected the normal and safe operation of the tunnel. The degree of expansion is of great significance to the operation and maintenance of structures. [0003] Nowadays, conventional non-destructive testing methods for concrete steel bar corrosion include analytical method, electrochemical method, resistance probe method, ray method, etc. These methods are mainly for local microscopic inspection of steel bar corrosion. Low, it is impossible to quickly locate the location of steel ...

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Problems solved by technology

[0005] Patent CN 108982571A discloses a device for non-destructive detection of rust expansion of reinforced concrete based on a heat-insulating box, a connecting scale, an infrared thermal imager and a computer. The device has a simple structure, but requires manual control of the connecting scale for detection. Only one rust swelling position can be detected, the detection efficiency is low, and the applicability of the device in tunnel engineering is not high due to the complex site conditions of the tunnel, limited space, low visibility, and no solar radiation; patent CN 110310258 A is disclosed A method for evaluating the corrosion degree of steel bars in concrete components is proposed. The fractal dimension value of rust cracks is calculated by processing the image of concrete rust cracks with MATLAB software, and the corrosion rate of steel bars inside concrete is calculated based on the crack fractal dimension value. This method The operation is simple, but it is necessary to pre-determine the location of the rust swelling crack and obtain the image before evaluating it. However, the cracks in the actual tunnel include not only the rust swelling crack of the steel bar, so the work efficiency of this method is not high, and the location of the disease cannot be accurately determined, and the evaluation method is relatively simple

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