Visual perception of retaining walls in mountainous landscapes: an aesthetic quality assessment of post-earthquake geohazard prevention projects in Jiuzhaigou, China

• Post-earthquake mountain retaining walls require dual focus on disaster prevention and visual harmony with landscapes for sustainable mitigation. • Aesthetic evaluations remain consistent across diverse respondent backgrounds, revealing universal perceptual priorities. • Targeted ecological treatments (vegetation, color matching, slope reduction etc.) significantly boost aesthetic integration and visitor experience. Architectural aesthetics are integral to mountainous landscapes, yet post-earthquake retaining walls—critical for geohazard mitigation—often conflict with natural scenery, undermining visitor experience. While prior research has examined technical functionality or isolated aesthetic factors (e.g., vegetation), two actionable gaps persist: (1) quantifying multi-stakeholder aesthetic consensus amid ecological treatments and (2) translating perceptual insights into field-tested design rules. This study addresses these by integrating quantitative physical parameters (geometric: height, slope, length; visual: color harmony, spatial positioning) of 9 pre- and post-ecological retaining walls in Jiuzhaigou with multi-stakeholder perceptual data (355 valid responses from tourists, students, and local staff) via the Scenic Beauty Estimation (SBE) method. The results indicate that enhancing vegetation coverage on the external space of retaining walls and reducing the color distance between retaining walls and surrounding forests can significantly improve their visual integration with the landscape. The overall aesthetic perception of the evaluators tends to be consistent, with ecologically treated walls 8b, 6b, and 9b appearing more natural and having stronger visual beauty. Additionally, the transformation of the top shape and positioning of retaining walls is considered a key factor in increasing SBE. The study emphasizes the importance of adaptive and environmentally sensitive designing strategies for ecologically treating retaining walls of different locations and scales. This research bridges ecological engineering and landscape aesthetics by: (1) Providing empirical validation that multi-stakeholder aesthetic consensus is attainable through strategic ecological treatments; (2) Offering evidence-based design rules for post-disaster retaining walls. These insights hold global relevance for nature reserves and scenic areas, illustrating that harmonizing safety with visual appeal can simultaneously bolster disaster resilience and visitor well-being. Limitations and future work (e.g., cross-climate validation) are noted to inform subsequent studies.