The collapse of a 30-year-old hotel building in Suzhou, Jiangsu Province on 12 July 2021 raised legitimate questions about the identification of old buildings’ condition and risks stemming from remedial operations. This short communication reports and investigates the causes of this accident, which led to 17 deaths and 5 injuries. Subsequently, it describes the rescue actions undertaken, including logistic means, operational strategies, and procedure sequencing. The causes of the accident were attributed to: (i) the poor quality and fragility of the building, (ii) illegal renovations and extensions, as well as (iii) the laxism of relevant departments that failed to timely check the risk level of the building before these renovations. Thanks to efficient organization and management, the rescue operations were completed within 42 h. Based on this preliminary analysis, some recommendations are proposed to prevent similar incidents in the future.

After extracting the longitudinal seam (LS) LiDAR detected data inside shield tunnel, although most can be obtained, some are obscured by tunnel objects and scanning limitations . Additionally, some segment point clouds are misidentified as seams, leading to extraction inaccuracies. Therefore, this study proposes an inference method based on geometric information to identify the extracted LS point clouds to estimate the longitudinal seams' locations that could not be extracted. Moreover, this method is applied for validation in a section of the Luoyang Subway Line 2 tunnel [1]. Developed an inference method based on geometric information for shield tunnel; Application of proposed method to identify the locations longitudinal seams; The proposed method is validated in a section of the Luoyang Subway Line 2 tunnel.