The properties of earthen monument soil oriented the material aging: A case study of the Suoyang ancient city

Due to exposing to atmospheric environment, the material of earthen monument sites deteriorated under the long-term influence of rainfall, wind-sand and temperature changes. In order to provide the basic parameters for the further research on the mechanism of materials aging, the world heritage site of Suoyang ancient city was taken as a research object, the physical, chemical, thermal and mechanical properties of the earthen monument soil were tested and analyzed through laboratory tests. The results show that the soil used for walls construction in different directions are low liquid limit clay, the mineral composition is mainly quartz, feldspar, mica, chlorite, calcite and dolomite, and the soluble salts are mainly NaCl and CaSO₄. The composition of soil particles and minerals in different direction cause the differences of physical and mechanical properties. The total amount of soluble salt in the east wall is larger, and the degree of mineral weathering is the highest. The thermal conductivity and diffusivity of soil in the west wall is the lowest, and the thermal degradation damage degree is the largest. The structure of primary rammed earth is better than the remolded sample, and it has higher mechanical properties of resisting compression and shear damage. In the process of soil ruins reinforcing, the layered ramming is beneficial to improve the structural stability.