%0 Journal Article
%T The Concavity of the Great Pyramid Can Be Derived from Inward Sloping Courses Needed for the Stability
%A Akio Kato
%J Archaeological Discovery
%P 65-106
%@ 2331-1967
%D 2023
%I Scientific Research Publishing
%R 10.4236/ad.2023.112004
%X The Great Pyramid has the character of concavity that each of its four faces is slightly indented along its central line. Applying the geometry on an inclined plane, we show that this concavity could be derived from its inner structure of inward sloping courses gently inclined towards the center of each course, at about 11 degrees to the horizontal, i.e., the slope 1/5 by the ratio of ¡°rise over run¡±. We explain why the inclined layers together with the reinforced base were necessary for the long-term stability of the Pyramid against the severe natural forces like the high gravitational compression, earthquakes and rainstorms, pointing out the feasible fact that the Pyramid has experienced severe rainstorms more than 500 times during the 4500 years. The crucial point about stability is that the effects of such natural forces are quite different between the core of inclined courses and that of truly level courses in the sense that the former can be tightened to become stronger over time, but the latter would be disintegrated to be weaker over time. Scaled-down models of the Pyramid are introduced to understand the large-scale dynamics of the Pyramid. In particular, the small model reduced by 10^{-3} helps us to imagine the transformation of vertical into lateral forces, pointed out by Mendelssohn. On the other hand, the Step Pyramid of Djoser can be identified almost as the half-sized model of the Great Pyramid when the Great Pyramid was assumed to be composed only of truly level courses. And this identification tells the fate of the Great Pyramid only of truly level courses that it would have almost collapsed until now like the Step Pyramid before the recent restoration.
%K Great Pyramid
%K Concavity
%K Rheology
%K Model
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=123430