Mechanism And Simulation Of Efflorescence At K9901 Funerary Pit Of The Emperor Qin

The earthen sites are precious historical and cultural heritage that contain rich humanistic message and have important archaeological and scientific value. The architectural technology and cultural relics of K9901 funerary pit of the Emperor Qin are rich in historical information, which may provide important information for the history and culture of entertainment, dress and other aspects of the archaeological work in the Qin Empirethat are of great archaeological and cultural significance. However, since the pit exploration, K9901 pit has been subject to damage of different degree under the inflenced of conservation environments and internal factors, salt demage is even more serious. Security and stability of earthen sites have been serious threatened.. In this study, field investagation was conducted first to find the major existing diseases, and the soil physicochemical properties were measured. Furthermore, soil water and solute transport were simulated using soil columns, soil water and salt transport under different groundwater levels were simulated, while using Hydrus-1D model to simulate water flow in this procress. Meanwhile, we quantified soil moisture dynamics along profile in 30 years when the groundwater level was 10 m. Finally, we simulated the process of salt accumulation at soil surface of different salts under different concentrations. The main results were as follow:(1) As affected by external environmrnt, salt crystalization, efflorescence, collapse, crack, flake peel and other diseases exist at K9901 pit of Emperor Qin. In addition, these diseases interact and constitude a direct threat to the pit security and disease prevention.(2) Groundwater and soil water move up gradually through capillary force, soil salinity moves upwards accompanied with moisture migration, especially there will have a salinity peak when wetting front passes through. Salt will gradually accumulates at the soil surface under the influence of evaporation. After 60 days, the EC of 0-5 cm soil layer was significantly higher than the underlying layer, and EC decreased gradually with the increasing soil depth.(3) The Hydrus-1D model could accurately simulate soil water migration and fast increasing of soil moisture caused by shallow groundwater table. The simulation of long time series showed that under the influence of stable groundwater table, the time for soil water moving upward for 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 m were 0.02, 0.14, 0.49, 1.2, 2.47, 4.47, 7.47, 11.7, 17.46, 25.00 years, respectively. This indicated that salts will migrate upward with moisture and accumulated at the soil surface after a long time period and constitude diseases like salt crystalization, efflorescence even though groundwater table was quite deep.(4) Salt crystalization simulation experiments showed that salt of different concentration accumulated at the soil surface under the influence of evaporation. But the salt type and concentration have a significant impact on accumulation procress, the EC of the 0-1 cm layer of soil clods with Na Cl and Na NO3 increased rapidly in the first three days and then tend to stable; while the EC for the soil clods with Na2SO4 always increased during the experiments. The EC of 0-1 cm of soil clods with 0.1 mol/Kg Na Cl also always increased within the experiment.(5) Contribution of different type salt to efflorescence is different, salt crystallization and efflorescence can be seen easily at the surface of soil clods with Na2SO4 compared with that with Na Cl and Na NO3.