This paper simulates the degradation of a 20 m-tall shaft lining in thick topsoil at the vertical depth of 500 m. The simulation was carried out under the similarity theory. Three reduced scale models were prepared from the original structure. The first model was subjected to circumferential load and then cured naturally, the second model was subjected to circumferential load and then soaked in corrosive solution, and the third model was subjected to circumferential and vertical loads and then soaked in corrosive solution. Without changing the circumferential load, vertical load was applied to the three models until they failed. The three models were found to have similar failure patterns: the uniform cracks first appeared at the top and bottom of the outer lining; the concrete of the inner lining cracked, and the upper part of the shaft lining was crushed, showing a diagonal shear failure. Model 1 had greater cracking load and ultimate load than model 2 and model 3. This is because the coupling between vertical and circumferential loads induces micro-cracks between the inner and outer linings, and thus accelerates the corrosion of the RC shaft lining in the corrosive solution.

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The air shafts of coal mines contain solid, liquid, and gaseous substances that corrode concrete under conditions of relatively high temperature and humidity. The coupling of various factors decreases the concrete strength and thus the bearing capacity of the air shaft lining. In this study, concrete corrosion tests were carried out by simulating the complex environment of a coal mine air shaft lining to study the variation in the concrete stress-strain curve. For corroded concrete specimens subjected to very low stress, the microcracks and holes were closed, generating a large deformation, indicating severe concrete corrosion. The longer the corrosion time was, the gentler the initial slope of the curve. Finally, the uniaxial compression constitutive model of corroded concrete was established based on the Weibull distribution of three parameters, and the model curve was compared with the experimental curve. This model can not only predict the change of the stress-strain curve of high-strength concrete in a coal mine air shaft environment but also provide theoretical reference for the application of high-strength concrete in an air shaft environment.

In the coal mining industrial environment, the materials of RC bunkers suffer from serious aging problems. The cracking and deterioration of concrete and the corrosion of steel reinforcement lead to a degeneration of structural performance and a decline of structural reliability. In this paper, based on on-site detection and coal mining ground industrial environment, the deterioration characteristics of RC bunkers were tested. The investigation involved the apparent characteristics, carbonized depth, compression strength of concrete, reinforcement distribution and cover thickness, corrosion rate and mechanical properties of reinforcement, decline degree of bunkers, and so on. Then a design review check was done. Combined with the above information, the cause and mechanisms of cracking and damage of the structure were studied; finally, the problems of RC bunkers were targeted and improved. The work provides a reference method for repairing a deteriorated RC bunker in an aggressive service environment.