Rockburst is a difficult problem in underground resource development and infrastructure construction. With scientific and technological progress, more research technologies and methods to prevent rockburst have been proposed and applied. Research content has become more comprehensive, and positive progress and achievements have been made. However, due to the complexity of rockburst control factors and the sudden occurrence of rockburst, the occurrence mechanism and accurate prediction of occurrence intensity and time are still difficult worldwide problems. In this paper, the research development and achievements of rockburst are reviewed. Firstly, various definitions and types of rockburst are briefly summarized. Then, research progress and achievements in four aspects are comprehensively reviewed, including methods and techniques of rockburst research (theoretical research, numerical simulation, physical model tests and in situ monitoring), mechanism of rockburst, classification and prediction of rockburst (empirical criteria, in situ monitoring, mathematical model approaches and rockburst chart) and prevention and control of rockburst. Of particular significance is that the classification and prediction with prevention and control are summarized in detail. Finally, limitations, deficiencies and some promising directions for future research are listed.
24 September 2022 in Journal of Biomolecular Structure and Dynamics
To investigate the binding characteristics of pesticide ethiprole (ETP) with serum albumin is of great significance for pathological analysis of pesticide poisoning, gene mutation, and clinical detection. In present work, the binding characteristics of ETP with a model protein BSA has been estimated by means of multi-spectroscopic approaches integrated with computer simulation. The outcomes testified that the intrinsic fluorescence of BSA was mainly quenched by ETP in a static quenching mode and the stable ETP-BSA complex with the stoichiometry of 1:1 and the binding constant of 6.81 × 103 M−1 (298 K) was produced. The outcomes revealed that ETP combined preferentially to the subdomain IIA (Site I) of BSA and caused the decline in the content of α-helix of BSA and the enhancement in the hydrophobicity of environment centered on Trp residues. The outcomes of experimental and theoretical studies provide the sufficient evidence about the driving forces for the complexation of ETP with BSA, which included van der Waals forces (vdW), hydrogen bonding (H-bonding) interaction, and hydrophobicity. Simultaneously, the theoretical calculation results also confirmed the existence of the significant changes in the physicochemical natures of ETP including molecular conformation, dipole moment, frontier orbital energy, and the atomic charge distribution, which was a responsible for the complexation with BSA. Communicated by Ramaswamy H. Sarma
Owing to the continuous increase in mining depth, Yichang phosphorite mines in China have entered the field of deep mining. The frequency of rockburst disasters is increasing. In situ experience indicates that the practice of spraying water onto a working face after blasting is an effective method of rockburst prevention. In order to investigate the underlying mechanisms of rockburst prevention by watering in phosphorite mines, a series of uniaxial compression laboratory experiments was carried on phosphorite samples under dry and water-saturated conditions with an acoustic emission (AE) monitoring system. A high-speed camera was used to record the failure process and pattern of a given rock sample prior to rockburst. The effects of water on the mechanical properties and fracturing characteristics of phosphorite failure were determined. Experimental results indicate that water reduces the uniaxial compressive strength and Young’s modulus. Saturated phosphorite causes more small fragments after it fractures. A Gaussian mixture model (GMM) clustering algorithm was utilized to analyze the crack propagation patterns of rock samples during the entire process. It was determined that during the unstable crack propagation phase, the presence of water makes the shear characteristics become more obvious. Water reduces releasable strain energy which is consumed by internal damage and plastic deformation of the rock sample. Moreover, the mechanism of watering for rockburst prevention is discussed from both macro and micro perspectives. The primary reasons for this are the transfer of stress concentration zones and stress-releasing effects via microcrack propagation on the working face.