Study of Remedial Measures for Existing Unauthorised Basement Over-excavation Renovation Works

Comprehensive over-excavation renovation works of an unauthorized basement have been studied. Based on the identification of safety hazards and taking into full consideration the uncertainty of structural instability induced by the over-excavated basement, the small construction site and the short construction period, the overall treatment plan combining temporary risk reduction and permanent reinforcement was proposed. The combination of geotechnical and structural measures, such as drainage, backpressure, light weight foam concrete backfills, high pressure rotary pile foundation reinforcement, and the addition of a new pile bearing platform were used. Finally, the effectiveness of the combined geotechnical and structural reinforcement measures in the remediation of the unauthorized basement was verified by combining on-site monitoring. The research results can provide some reference significance for the design and construction of similar renovation works.