Geo-Environmental and Structural Problems of the First Successful True Pyramid, (Snefru Northern Pyramid) in Dahshur, Egypt

Significantly, Snefru northern pyramid is the first successful true complete Pyramid was built in Egypt. It has suffered from different kinds of geo-environmental impact and other mechanical and dynamic actions; aspects of structural deficiency and building material decay are recorded and monitored. The scope of this pilot study is to ensure the structure stability and weathering vulnerability of the building materials of Snefru northern pyramid under different environmental, geotechnical and seismic loading conditions. It has been achieved through the following steps: (1) Evaluation of the building materials; includes the integrated petrography study, petro-physical and geo-mechanical testing (2) Estimations of relevant factors affecting these building materials (3) integrated modeling of the pyramid geo-environment conditions. The present study reveals that the Snefru pyramid is considered the only composite pyramid structure, which is composed of local Dolomitic sandstone body blocks which had been quarried from Dahshur plateau, and joining with pure hydraulic lime mortars and covered with imported casing limestone layers from Tura Formations. Stripped from its limestone casing, this pyramid reveals the reddish sandstone used to build its core. This explains its modern-day name, the red Pyramid. The detailed analytical study proved that this important monument present poor engineering properties and low safety factors for both static and seismic loading. The present study indicates the dependence of the mechanical properties on the petro-physical and the geochemical properties of the studied construction materials. Modeling the properties indicates a reliable correlation between the different parameters. Consequently a well-focused strengthening and retrofitting program is deemed necessary.