A novel approach of mitigating fault-slip induced dynamic disasters based on liquid super-lubricity

Fault-slip induced dynamic disasters, such as seismicity and rockburst, pose significant risks to various subsurface engineering projects, and the currently used mitigation methods often involves strategies of modulating in-situ stresses in the surrounding rocks near fault planes timely. Here, we propose an alternative strategy for mitigating fault-slip induced dynamic disasters in terms of reducing friction of faults based on liquid super-lubricity principle. A series of friction experiments were conducted on fault specimens in which deionized water (DW), polyethylene glycol (PEG) solution, graphene oxide (GO coating), PEG with graphene oxide additives (GO in PEG) and ethyl alcohol aqueous solution with graphene oxide additives (GO in EA) were served as lubricants. The experimental results demonstrate that friction coefficients of flat and rough fault specimens were reduced by 3 % and 4 %, 46 % and 28 %, 62 % and 23 %, 74 % and 51 %, 62 % and 48 %, respectively, when lubricated by DW, PEG solution, GO coating, GO in PEG, and GO in EA compared to dry condition. Microscale friction tests and surface characterization were conducted to elucidate the lubrication mechanism of GO additives in PEG. The adsorbed PEG film and graphene layers on contact asperities effectively withstood high pressures, exhibiting low shear stress and preserving a relatively rough surface texture. The results suggest that injecting lubricant solutions into natural faults to modulate friction coefficients can effectively control fault slip and mitigate the risk of dynamic disasters.