Response Of Liangzhu Earthen Site Disease To Microenvironment During Archaeological Excavation

Moist sites are sites which have high moisture content or in high humidity environment. Sites have been kept for centuries under stable environment, and have reached a equilibrium with T and RH. During archaeological excavation, the moisture content of sites decrease rapidly.After being Stayed a long time underground, exposure to the atmospheric conditions and confrontation with weathering factors, various disease occurs such as immediate decay, deterioration and collapse. To protect the cultural remains temporary or long-term sheltering is widely used. The protective shelter design should be designed base on the concept of microenvironment. Microenvironment is a local weather condition related to the small location, eg, a corner of street, a square, a room, where the monument or the object is sited.Hot Disk heat constant analyzer was used to test the thermodynamic parameters of soils from Liangzhu earthen monument sites, and study the influence of dry density, water content on thermodynamic parameters. Laboratory simulation test was conducted to establish to the relation between shelter permeability and soil moisture content. At last, a discussion was made to give a guideline for shelter design in humid area.(1) Diseases of earthen monument in humid states.The diseases of archaeological excavations have two aspects which included surface degradation and structural damage. The former includes cracking, peeling, salting out pulverization and biological diseases, water erosion, etc.(2) Thermal property of Liangzhu earthen monument soilsThermal parameter tests were carried out by Hot Disk TPS2500s Thermal Constants Analyzer to measure the thermal parameters (thermal conductivity, thermal diffusivity and volumetric specific heat) of soils. Test results illustrate that the thermal conductivity of soil increase with the increase in water content and dry density. By data fitting method, good linear relationships were founded between thermal conductivity. Volumetric specific heat also increases with the increase in water content and dry density, but the increase of the amplitude decreases.(3) Laboratary simulation testsome boxes with different air permeability were designed to reflect the protective effect of shelter at site. Laboratary simulation test shows that soil water content increases with the increase of air permeability content. The higher air permeability content make soil content stabilize easily. Higher air permeability than 30% shows a similar effect on soil water content. When the air permeability content is more than 20%, dry density have less impact on the change of soil water content. The shrinkage of soil with density of 1.50g/cm3 is greater than others. When water content exceed 10%, the soil with dry density of 1.55g/cm3 have similar shrinkage with 1.60g/cm3. The dry density of 1.65g/cm3 and the dry density of 1.65g/cm3have similar shrinkage.(4) Guideline for the design of protective shelterThrough the research on response relationship between diseases of archaeological excavations in moist sites and microenvironment, we know that a protective shelter should be designed from the view of microclimate. So to reduce the damage of sites due to the microclimate change during excavation.