Risk assessment of soil subsidence in old building renovation projects based on geotechnical data and exploratory boreholes.

Mohammad Taghi Ahangariyeh¹

1) Structural Civil Engineering Expert, Tabriz Metropolitan Municipality, Iran

IOI Code : AACZ-ABGDAC
Publication : The 5th International Conference on Seismic Retrofitting(5icst.ir)
Abstract :
    Soil subsidence is one of the hidden yet destructive risks in old building renovation projects (reconstruction and modernization), which can lead to cracking of adjacent structures, damage to underground utilities, project stoppage, and heavy legal costs. This research aims to develop a framework for assessing soil subsidence risk in such projects based on geotechnical data and exploratory boreholes. Key indicators include soil type, borehole depth, groundwater level, standard penetration test (SPT) results, and initial effective stresses. Using semi-quantitative methods and analytical subsidence models, three risk levels—low, medium, and high—are defined. The results indicate that in 70% of boreholes with soft clay soils and high groundwater levels, there is a risk of subsidence exceeding the permissible limit (greater than 25 mm). Applying this approach is essential in pricing old renovation properties and making decisions regarding the foundation method (piled vs. spread foundations).

Keywords : soil subsidence risk assessment old renovation properties geotechnical data exploratory borehole