远场水下爆炸下面板堆石坝防渗面板的破坏模式与机制OA

The concrete face slab is the primary impervious structure of the concrete-faced rockfill dam(CFRD),its blast resistance is crucial to dam safety.However,there is still a lack of systematic understanding of the damage mechanisms of the face slab subjected to underwater explosions.This study aims to reveal the failure modes and mechanisms of the face slab of CFRDs subjected to far-field underwater explosions.To this end,the reliability of the numerical method was verified by comparing the test results with the numerical results.Then,the impact process of the underwater explosion shock wave on the CFRD was investigated based on a 100 m high CFRD.The dynamic response stage features of the face slab were analyzed,and the damage modes and mechanisms of the face slab were revealed.The results indicate that the failure of the face slab follows a typical two-stage evolution pattern.The initial shock wave action stage only induces localized micro-damage at the slab boundaries,while the subsequent global response stage dominates the formation of serious damage to the face slab.During the global response stage,horizon-tal tensile cracks first appear in the face slab near dam crest and expand rapidly downwards,eventually leading to nearly complete cracking of the face slab within the elevation range of(0.6-1)H.The damage mechanism in the shock wave action stage is the local tensile failure of concrete caused by the reflected tensile wave at the slab boundar-ies.In contrast,the cracking mechanism during the global response stage is driven by the increase in the dynamic ten-sile stress increase within the face slab,which is primarily induced by its dynamic separation behavior(detachment from the underlying cushion layer)within the(0.6-1)H elevation range.This study elucidates the new mechanisms of failure of the face slab with"dynamic separation behavior"as the core driver and provides a theoretical basis for the anti-explosion resilient design of the CFRD.