Assessing architectural interventions in rock-cut heritage: a resilience-based restoration approach at Longmen Grottoes, China

The loss of protective structures exposes cave temples to climatic disturbances, but the environmental effects of their restoration remain insufficiently quantified. This study develops an environmental-resilience-oriented restoration framework integrating historical reconstruction, field monitoring, microclimate and solar-radiation simulations, and multi-indicator evaluation. Using Cave 1280 at the Longmen Grottoes, three scenarios were compared: no protective structure, a gallery-eave-type scheme, and a hall-type scheme. The results show seasonal vertical temperature and relative humidity gradients. The hall-type scheme provides stronger thermal buffering and reduces solar radiation by 82–97%, but restricts air exchange and expands low-velocity zones, increasing moisture-retention sensitivity. The gallery-eave-type scheme provides weaker buffering but maintains better airflow continuity and spatial openness. The integrated assessment favors this scheme when ventilation, reversibility, and landscape compatibility are considered. Greater enclosure therefore does not necessarily ensure better conservation. The framework supports site-specific restoration decisions for similar semi-open grottoes.