Method and device for detecting rust expansion of shallow reinforcing steel bars of tunnel lining

Abstract

The invention discloses a method and a device for detecting the rust expansion of shallow reinforcing steel bars of a tunnel lining. When steel bar rust expansion exists on the surface or the shallowlayer of the tunnel lining, a potential steel bar rust expansion position can be positioned according to temperature difference, and a steel bar rust expansion degree is judged; after a steel bar rusts and expands, a rust expansion crack is generated on the corresponding lining surface and is an along-the-bar crack; the rusted and expanded part of the steel bar can be positioned in an auxiliary manner by acquiring the position distribution of the along-the-bar crack on the lining surface; after the steel bar rusts and expands, the rigidity of an area corresponding to the steel bar is reduced,and as a result, the surface of the structure deforms obviously relative to complete parts on two sides; and the widths and deformation conditions of the crack of the lining surface are different dueto different rust expansion degrees of the steel bar, and thus, on the basis of the relationship between the rust expansion of the steel bar and the surface deformation of the lining and the width ofthe crack and in combination with the relationship of temperature change in infrared thermograms, the rust expansion part of the steel bar can be determined, and the rust expansion degree of the steelbar is 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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