Research on arch dam performance considering spatiotemporal effects of fault parameters

• Reveals spatially non-uniform distribution characteristics of fault mechanical properties under confining pressure. • Identifies time-dependent degradation mechanisms of fault mechanical properties under cyclic loading. • Establishes a novel framework for long-term arch dam abutment stability assessment incorporating spatiotemporal fault property evolution. Fault is a typical unfavorable geological structure, which is a common engineering problem in arch dam construction and seriously threatens the operation safety of arch dam. The fault zone is usually composed of a variety of mineral particles, rock fragments and cements, which is easily affected by the ' confining pressure effect '. The mechanical properties of deep faults are often better than those of shallow faults. At the same time, the cyclic load formed by the rise and fall of water level during reservoir operation will weaken the mechanical properties of faults under long-term action. In this paper, the spatial gradient distribution of fault mechanical parameters is realized by writing User Material Subroutine (UMAT), which conforms to the non-uniform distribution of fault mechanical properties in space. At the same time, the coupling simulation of time-dependent damage evolution also provides a dynamic safety threshold criterion for the life-cycle performance evaluation of arch dams. Combining the two, the redistribution of fault mechanical properties in space and the weakening effect of fault time in the actual operation of arch dam are realized, and the fault stability evaluation system of space-time multi-dimensional coupling is constructed to provide scientific support for the safe operation of arch dam in the whole life cycle.