Stress mechanism for the rammed layer interfaces of earthen heritage sites with different treatments

Abstract

Abstract Layer interfaces are the weakest parts of traditional rammed earthen structures. Different ramming technologies for the interfaces between layers were found to have a significant effect on the level of destruction. Accordingly, four interface treatment methods were simulated to reveal the mechanism and damage mode for the interfaces between different layers: no interface, fine interface, coarse interface and rammed pit interface. Moreover, elastic wave velocity, tensile strength, compressive strength and shear strength tests were performed to explore the effects of different interface treatment technologies on different layers. The results showed that the tensile and shear strengths of the rammed earthen layer interfaces were much lower than the compressive strength. The tensile strength was only 1/30 of the compressive strength, which was the decisive factor in the ultimate destruction of such sites. An effective measure to improve the shear strength of rammed earthen sites is to increase the depth and uniform area of friction of the layer interface, and the roughness of the contact surface between layers. The interface treatment with the rammed pit layer provided superior results to the coarse and fine layers. The abovementioned results provide a theoretical basis for the scientific cognition of traditional ramming and consolidation technologies of earthen sites.