Study Of Simulate Experiment On Water-salt Transfer Inside Earthen Site Under High Humidity Condition

As the concept of preventive conservation was increasingly accepted by more and more people, to build a protective architecture on the original site is becoming the major method in the field of earthen site protection. The protection hall of burial pits in HanYangling museum is the first all-underground museum in China. A closed glass space was used to protect earthen site in this museum. The advanced protection idea got lots of attention and it represents the direction of earthen site museum construction in the future.Compared with traditional open building museum, obviously the HanYangling museum can conserve the site more effectively. But even if the site was conserved in a condition of high humidity, some soil disease emerge in the surface of site in ten years, such as crack, powder and salt concentration. After research we know these diseases have to do with the action of water and salt in the site, and which is directly concerned with environment.The NO.13 burial pit is an independent space in the underground building of HanYangling museum. The atmosphere environment kept the humidity a very high level for a long time. I took the NO.13 pit as research object and did an experiment to simulate movement of water and salt in the closed environment with high humidity.After two stage experiments with different groundwater condition, I have analysed the experiment data and atmosphere data to a conclusion:In the closed space with high humidity, soil column、groundwater and atmosphere formed a dynamic mass-transfer equilibrium system. In this system the evaporation is very weak and ions move up slowly, the steam condense on the soil surface driving the ions downward. In the first stage, the water content and movement was mainly controlled by the depth of groundwater but in the next stage surrounding environment have the prior influence.After analysis of the site environment, it was explained that a protective architecture can reduce the evaporation, but a closed room can be better at controlling movement of water and salt. Although the surrounding environment now is stable, but water-off in low speed continued and which is going to be a long-term problem in the future.