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In the present study, we address an important and increasingly relevant topic in mining safety and efficiency, namely the stability of open-pit bench slopes subjected to daily heavy truck cyclic loading. Specifically, we focus on the stability of Zhahanur open-pit slope (Inner Mongolia region, China) and investigate the potential role of daily heavy truck cyclic loading in bench slope instability. To this end, we incorporate a stress corrosion model into the particle flow code to develop a time-dependent deformation model of the rock. With the established model, we quantitatively analyse the effect of heavy truck cyclic loading on the bench slope stability. Our results support the hypothesis that daily heavy truck loading can cause gradual downward deformation of a rock mass, leading to slope instability. To validate our numerical modelling results, we compare and analyse them with in situ monitoring data. Our study demonstrates the significant impact of daily heavy vehicles on bench slope stability in open-pit mines and provides a practical tool for assessing the long-term stability of open-pit bench slopes and optimising mining operations. [ABSTRACT FROM AUTHOR]

Geothermal resources, which are located deep in the Earth, are expected to become one of the important ways to break China's energy dilemma, and promote the realization of carbon peak by 2030 and carbon neutrality by 2060 with the advantages of abundant reserves, clean and renewable. In the process of developing hot dry rock(HDR), the problem of water-rock interaction under high-temperature and high-pressure environment is faced. Under the coupling action of multiple fields such as thermal-hydraulic-mechanical-chemical(THMC), the stress corrosion effect and fatigue deterioration of rock mass will induce rock micro-cracking and fracture expansion, nucleation and clustering behavior, which will affect the heat exchange efficiency of enhanced geothermal system(EGS)and stability of geological body. This is the bottleneck that restricts the long-term safe development of HDR and needs to be broken. Based on experimental exploration, theoretical modeling, numerical analysis and other multi-measures, cross-scale methods for multi-field damage study on HDR under high-temperature and high-pressure, the stress corrosion effect of HDR under high-temperature, high-pressure and water environment was analyzed, the dynamic process and engineering response of the structural evolution of HDR reservoir were elucidated in the cyclic production process of low-temperature mass and high-temperature geological body cyclic heat exchange, and then the fatigue deterioration damage mechanism of HDR reservoir under THMC multi-field coupling was revealed, and the theoretical support and geological guarantee for the efficient and safe development of deep geothermal resources in China were provided. However, it is still urgent to carry out further research on the fatigue deterioration mechanism and long-term stability of HDR under the stress corrosion effect of rock mass and THMC multi-field coupling action of EGS, such as the long-term strength evaluation model considering stress corrosion effect and fatigue damage, the evaluation method of long-term stability based on cross-scale fatigue damage, and THMC multi-field coupling numerical method for reservoir reconstruction and fracture network evolution. [ABSTRACT FROM AUTHOR]

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SUMMARY Following the stress release model (SRM) proposed by , we developed a new multidimensional SRM, which is a space-time-magnitude version based on multidimensional point processes. First, we interpreted the exponential hazard functional of the SRM as the mathematical expression of static fatigue failure caused by stress corrosion. Then, we reconstructed the SRM in multidimensions through incorporating four independent submodels: the magnitude distribution function, the space weighting function, the loading rate function and the coseismic stress transfer model. Finally, we applied the new model to analyse the historical earthquake catalogues in North China. An expanded catalogue, which contains the information of origin time, epicentre, magnitude, strike, dip angle, rupture length, rupture width and average dislocation, is composed for the new model. The estimated model can simulate the variations of seismicity with space, time and magnitude. Compared with the previous SRMs with the same data, the new model yields much smaller values of Akaike information criterion and corrected Akaike information criterion. We compared the predicted rates of earthquakes at the epicentres just before the related earthquakes with the mean spatial seismic rate. Among all 37 earthquakes in the expanded catalogue, the epicentres of 21 earthquakes are located in the regions of higher rates. The map of predicted earthquake rates at the ending time (1997 January 1) suggests that the next destructive earthquake in North China is likely to occur in the regions south of Datong, north of Beijing and east of Hejian. [ABSTRACT FROM AUTHOR]

The crack state in the regenerator of the heavy oil catalytic cracking unit of Daqing Petrochemical Complex is summarized. The reasons for a large number of welding seam cracks in the regenerator-third-stage cyclone system of the heavy oil catalytic cracking unit are analysed. Correlated countermeasures to prevent cracks and several repair plans for the present cracks are proposed. The key technology and measures of repairs are described and could be used as guides for crack repair of similar equipment. [ABSTRACT FROM AUTHOR]