In this paper, self-sensing cemented soil composites were prepared using multi-walled carbon nanotubes and nano-magnetite as conductive fillers. The effects of mono-doped and co-doped multi-walled carbon nanotubes and nano-magnetite on the early mechanical properties, electrical properties, and self-sensing properties of the cemented soil composites under different forms of loading were investigated. The influence mechanism of multi-walled carbon nanotubes and nano-magnetite on the cemented soil composites was explored by scanning electron microscopy. The results indicate that the incorporation of nano-magnetite has the potential to enhance the early mechanical properties of cemented soil composites. While multi-walled carbon nanotubes enhance the integrity of the conductive network within the cementitious soil, they also mitigate the influence of the polarization effect. The dispersion of multi-walled carbon nanotubes in cemented soil composites can be enhanced through the co-doped multi-walled carbon nanotubes and nano-magnetite, thereby increasing its electrical conductivity. Furthermore, the co-doped multi-walled carbon nanotubes-nano-magnetite not only enhances the stress sensitivity of the cemented soil composites but also sustains a favorable linear relationship between cracks and electrical resistance changes, thereby facilitating more precise and comprehensive crack monitoring.

The process of land subsidence deals with the removal of excess pore water pressure and the compaction of soil mass under the effect of natural or human factors. The detrimental effects of land subsidence include changes in the morphology of the land surface and the formation of earth fissures, as well as structural and non-structural damage to surface and subsurface infrastructures. In Joshimath on 2nd January 2023, an incidence of ground subsidence occurred which damaged many buildings and infrastructures. This study addresses the exploratory work on rapid visual damage assessment of buildings based on method developed by National Disaster Management Authority (NDMA) and European Macroseismic Scale (EMS) - 98. The building vulnerability was assessed using building attributes like typology, number of storeys, area, construction materials, occupancy, configuration, construction practice etc. The damage attributes considered are based on siting issues, soil and foundation conditions, architectural features and elements, structural aspects and components, material & construction details, crack monitoring etc. In the critical buildings, cracks were monitored using crack meters. This study concludes out of total 2364 building surveyed, 37%, 42%, 20%, 1% buildings fall under Usable, Further Assessment, Unusable, to be demolished, grades respectively.