Performance and mechanism of crack prevention measures at interface between rammed earth supplement and original body in the erosion area of rammed earth sites

The interface cracking between the rammed earth supplement and the original site body, after construction, is a common issue for the reinforcement of the erosion area at the base of rammed earth sites. The on-site reinforcement experiments with four crack prevention measures are conducted: no-crack measures (WZ), setting a cushion layer (DC), interface anchoring (MG), interface grooving (KC) and a combination of cushion layer + interface anchoring + interface grooving (DMK). Continuous and synchronous monitoring of strain and moisture content is included. The development of macroscopic cracks at the interface, daily interface strain and accumulated plastic strain under each measure are analyzed, explaining the crack prevention performance and mechanisms. The results indicate that under the five operating conditions designed in this study, during rapid moisture loss, the development of macroscopic interface cracks, daily interface strain and accumulated interface plastic strain consistently ranked from the largest to the smallest are as follows: WZ > DC > MG > KC > DMK, with DMK showing the best crack prevention effects. Under this model, the interface bonding strength is mainly borne by the interfacial adhesion, anchoring force of the anchor bolts, the friction and shear pin force and the interlocking and bonding forces of the groove.