Monitoring Structural Stability and Deviation of the Choli Minaret Using Terrestrial Laser Scanning for Heritage

Laser scanning is the latest scanning technique that is used for many important purposes, such as 3D modelling of heritage objects, objects that require very accurate data collection, as well as in the fields of monitoring, as-built surveys, and many other fields. In this study, the inclination and deviation of the minaret was studied. Due to the importance of the Choli Minaret heritage, it was necessary to obtain reliable data to determine the amount of deviation of the minaret in the geometric and scientific manner. Therefore, the researcher used two precise modern surveying instruments, a total station and a BLK360 laser scanner, to determine and prove the amount of deviation of the minaret and determine the direction of deviation, inclination, and compare with the traditional and previous data based on creating 3D model of the minaret. The difficulty of creating 3D models of the minaret is due to the height of the minaret and the absence of any objects around it, as well as the presence of two staircases inside that are not visible from one another. A highly accurate 3D model for the minaret was created as a result and it was found that the minaret had inclined 71 cm towards the south direction. The collapse of the upper part and the concavity in the middle of the southern part of the minaret lead us to the fact that this deviation occurred gradually due to the rainfalls.