In order to accurately measure the mining‐induced stress, a new type of radial stress‐meter with a multipetal structure is developed in this study, and the cross‐sectional selection method and mechanical properties of the stress‐meter are studied in detail by various approaches. First, the expansion deformation law of the cross‐section is obtained based on theoretical analysis and numerical simulation, which shows that the input pressure first affects the size of the cross‐section and then affects the shape of the cross‐section. By comparing the evaluated parameters such as ovality and expansion diameter, it can be determined that the six‐petal structure is the optimal cross‐section shape. Second, the stress analysis results show that the troughs and inner sides of the peaks are the weak positions of the stress‐meter, where stress concentration is likely to occur and cracks are prone to form. Taking into account that plastic deformation dominates the entire expansion process, it is reasonable to use the ultimate strength instead of the yield strength to evaluate the failure of the stress‐meter. Third, there is a good linear relationship between the input pressure and the external pressure after expansion, which is verified by the specially designed triaxial hydraulic chamber loading experiment. The experimental results are in good agreement with the theoretical results. Moreover, under the same material conditions, the wall thickness of the stress‐meter should be as small as possible while ensuring sufficient expansion. The abovementioned research results prove that this new type of stress‐meter is feasible and reliable and also provide a solid foundation for the further integration of monitoring systems in mining engineering.
Zhang et al. (Thu,) studied this question.