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Typical seismic sway braces (SSBs) are composed of several bolted steel components. As the connecting bolts become loose, the stiffness and bearing capacity of SSBs decline from which their seismic performance degrades significantly. Based on the vibration response of the brace components, a framework of a vibration-based pre-alarming method for the bolt looseness of SSBs is created and established. Four damage indexes were constructed based on the methods of Fast Fourier Transform (FFT), Wavelet Packet (WP), Intrinsic Mode Function (IMF) and Hilbert-Huang Transform (HHT). Having tested and verified their sensitivity to the bolting torque of bolts, a multi-index hierarchical early warning system (MHES) was established by associating the four damage indexes with the tightening torque of the bolts, by which the threshold of the yellow (slightly damaged) and red (severely damaged) warnings were defined and confirmed. By means of the application in an actual project, the validation of the MHES was finally verified and confirmed according to its stability and accuracy. [ABSTRACT FROM AUTHOR]

Typical seismic sway braces (SSBs) are composed of several bolted steel components. As the connecting bolts become loose, the stiffness and bearing capacity of SSBs decline from which their seismic performance degrades significantly. Based on the vibration response of the brace components, a framework of a vibration-based pre-alarming method for the bolt looseness of SSBs is created and established. Four damage indexes were constructed based on the methods of Fast Fourier Transform (FFT), Wavelet Packet (WP), Intrinsic Mode Function (IMF) and Hilbert-Huang Transform (HHT). Having tested and verified their sensitivity to the bolting torque of bolts, a multi-index hierarchical early warning system (MHES) was established by associating the four damage indexes with the tightening torque of the bolts, by which the threshold of the yellow (slightly damaged) and red (severely damaged) warnings were defined and confirmed. By means of the application in an actual project, the validation of the MHES was finally verified and confirmed according to its stability and accuracy.

Common faults of coal mine conveying belt were analyzed as well as their causes, including splice breaking, longitudinally tearing, sideslipping, coal-water mixture and conny piling up, etc. Existing monitoring technologies for common faults of coal mine conveying belt were summarized as well as their main problems. For the problem that existing monitoring technologies only alarm after faults but cannot pre-alarm, an intelligent detecting and pre-alarming system for coal mine conveying belt was proposed which was based on machine vision.

Tailings dam is an indispensable part of mining safety production and environmental sustainability. The stability, monitoring, pre-alarming, and sustainability of tailings dam are crucial for mining disaster control, environment, and human beings. The paper introduces the damage of tailings dam failure by 44 typical accidents (2138 deaths in total), and then presents some developments and new insights for environmental sustainability and disaster control of tailings dam. Firstly, three kinds of methods for stability analysis of tailings dam were summarized and compared. Limit equilibrium methods (LEMs) were focused on Sweden methods, Janbu method, Bishop method, and Morgenstern-Price method. Numerical simulation methods were discussed about finite element method (FED), discrete element method (DEM), boundary element method (BEM), and finite difference method (FDM). Uncertainty methods were compared, including gray system evaluation method, reliability method, and fuzzy evaluation method. Secondly, the research progress in the field of safety monitoring and pre-alarming of tailings dam was reviewed, covering the aspects of traditional monitoring methods and coupled monitoring systems. Finally, the conception map of disaster prevention, disaster control, and environmental sustainability for safety management and environment to enhance cleaner production work in tailings dam was presented. The map for safety work and environmental sustainability achieves the goals from "lagging" to "real time", from "point" to "solid", from "surface" to "internal", and from "passive" to "coupled passive and active". • Comprehensive stability analysis with multiple methods improves dam reliability. • Pre-alarming systems using displacements and seismic monitoring are recommended. • The concept map for safety management and environment of tailings dam is proposed. • The monitoring methods from "surface" to "internal" are achieved. [ABSTRACT FROM AUTHOR]