Preservation of earthen relic sites against salt damages by using a sand layer

Abstract

Salt damage is one of the main problems facing the preservation of earthen sites in heritage museums. The use of salt-inhibiting materials on the surface of earthen sites to prevent damages could cause secondary damage. A method of placing a sand layer as a water and salt barrier was introduced and evaluated based on the law of unsaturated soil water and salt transport. The method involves placing a sand layer on the lower layer of the earthen site to inhibit the migration of water and salt from the deep soil to the surface of the earthen site. Experiments and numerical simulations were conducted to study the long-term effect and efficiency of water and salt barrier of sand layers with different particle sizes. The results show that the sand layer could successfully block the continuous upwards transport of water. The salt was shown to stagnate at the boundary between the bottom of the sand layer and the experimental soil. According to the simulation results, the water and salt barrier effect of the sand layer is proportional to the particle size of the sand layer. The sand layer with particle sizes much larger than the experimental soil has a durable water and salt barrier effect. These results are important for understanding the mechanism of salt damage to earthen sites and for the sustainable preservation of relics against salt damage in a soil environment.

Biocrusts protect the Great Wall of China from erosion

“…In addition, the soil-binding secretions and filamentous structures of biocrusts interweave to form a sticky network that wraps soil mineral particles and aggregates ( 37 ), promoting mechanical strength and aggregate stability against external erosive forces ( 38 , 39 ). Moreover, biocrusts continually absorb soluble base cations from the substrate to synthesize metabolic compounds, resulting in the mitigation of heritage salt corrosion ( 40 , 41 ). Furthermore, the carbon fixation of biocrusts enhances soil organic matter content, indirectly promoting aggregate stability and reducing the erodibility of rammed earth ( 42 ).…”

Low-carbon environmental control system for storage of earthen relics in exhibition hall: From the perspectives of nature based solution

“…1,4,6 Once excavated, the earthen relics have undergone significant energy and material exchanges with the external air environment, causing irreparable damages such as structural cracks and salt accumulation on the relic surface. 7,8 The fully enclosed exhibition hall is currently the most effective measure for earthen relics protection. 9 Besides, the enclosed exhibition hall has other multiple functions, such as exhibition, scientific research and education.…”

The exploration of a new technology: preservation of immovable silicate cultural relics against salt efflorescence by directional induction of water and salt migration

“…The principle of the technology is by reducing the suction of the matrix in the soil water transport layer. Generally, the larger the particle size used, the more durable its water-salt barrier effect [33]. This technique has been demonstrated to be effective to some extent, and it has the potential to destroy silicate cultural relics.…”