The safety distance of a tunnel under-traversing a slope body with a landslide-prone zone

At present,substantial scientific research achievements have been made in the research on landslide occurrence,movement mechanism,mitigation measures,and structural stability during tunnel excavation.However,the interaction mechanism of a tunnel under-traversing a slope body with potential landslides is still not well understood.Based on the field data provided by previous investigations in the study area,six sets of 1:100 laboratory experiment model tests were conducted to study the stability of the landslide-prone zone of the slope body with an under-traversing tunnel.The selected distances between the tunnel and the sliding surface are 1.5,3,and 5 times of the tunnel diameter,respectively.The experiment results show the interaction between the landslide-prone zone and the tunnel,elucidating the effect of potential landslides during the tunnel excavation process and the reaction of the landslide slip on the tunnel structure.Several conclusions are obtained:①During the process of tunnel excavation,the vertical displacement of the tunnel vault decreases with the increase of the buried depth.②The vertical displacement of the sliding surface increases with the increase of the buried depth of the tunnel.The horizontal displacement of sliding surface decreases with the increase of the buried depth.③After the occurrence of a rainfall-induced landslide,the vertical displacement of the tunnel vault in the 1.5-diameter-distance case is 57.29%greater than that in the 3.0-dismeter-distance case.④For a two-cave tunnel,it is suggested that the cave farther from the landslide toe should be firstly excavated since it may generate less structural deformation.

Design of high-performance and sustainable Co-free Ni-rich cathodes for next-generation lithium-ion batteries

Great attention has been given to high-performance and inexpensive lithiumion batteries(LIBs)in response to the ever-increasing demand for the explosive growth of electric vehicles(EVs).High-performance and low-cost Co-freeNi-rich layered cathodes are considered one of the most favorable candidates for nextgeneration LIBs because the current supply chain of EVs relies heavily on scarce and expensive Co.Herein,we review the recent research progress on Co-free Nirich layered cathodes,emphasizing on analyzing the necessity of replacing Co and the popular improvment methods.The current advancements in the design strategies of Co-free Ni-rich layered cathodes are summarized in detail.Despite considerable improvements achieved so far,the main technical challenges contributing to the deterioration of Co-free Ni-rich cathodes such as detrimental phase transitions,crack formation,and severe interfacial side reactions,are difficult to resolve by a single technique.The cooperation of multiple modification strategies is expected to accelerate the industrialization of Co-free Ni-rich layered cathodes,and the corresponding synergistic mechanisms urgently need to be studied.More effects will be aroused to explore high-performance Co-free Ni-rich layered cathodes to promote the sustainable development of LIBs.