Proposed methods of stabilizing the progressive cracks occurring in Iman Ali Al-Hadi Shrine, Samarra, Iraq

The Al Askari Shrine is a Shiite Muslim holy site in the Iraqi city of Samarra, 125 km north of Baghdad. It is one of the most important Shiite shrines in the world, built in 944 AD. It appears that the causation of the several cracks that recently developed in various locations of the Al-Askarī Shrine is due to differential settlement that in turn could have been caused by the dissolving of certain Gypsum layers of the underlying soil (with a gypsum content of more than 50%) and consequently the creation of cavities in the underlying soil layers. It will then be the collapse of the said cavities that would have consequently caused the proposed soil settlements. A brief history of this shrine is shown in Appendix I, and Appendix II contains some of the photos of the cracked areas of the Shrine; furthermore, Appendix III contains photos the very old Mosque located next to the Shrine and Appendix IV contains photos of a nearby structure (only a few metres away from the Shrine) that has developed extensive cracking all due to differential settlement. This paper comprises a desktop review of known documents and contains a proposal for the further assessment of the soil below the Shrine as well as several possible geotechnical solutions to arrest or slow down future differential settlements.