Quantitative Study Of Soil Porosity In Qin Shihuang Mausoleum Site And Analysis Of Water And Salt Migration In Unsaturated Zone Of Park

Soil porosity is the structural basis for its own function.At present,there are few domestic researches on the pore structure of the site soil,especially the soil in the hill area.Water and salt distribution in soil is the basis for the study of soil water and salt transport.Groundwater recharge is the final result of precipitation infiltration in the aeration zone,and is also a way for salt to pass through soil to contaminate groundwater.At present,water and salt migration in the aeration zone in the relevant site area is involved.There have been few studies on the impact on the ecological environment of the ruins and groundwater pollution.In this paper,based on CT scanning technology,the soil pore structure of different sites with different historical backgrounds in Pit 3 of Terracotta Warriors and Horses in the Terracotta Warriors and Horses of the First Qin Dynasty was studied,and the distribution and morphological characteristics of pores at different sites were revealed at multiple scales.As a result,it was revealed that the construction process of the site can reflect the pore structure characteristics of the soil to some extent.Based on the chlorine ion mass balance method,the groundwater recharge conditions under different land use patterns around the imperial cemetery site were assessed,and the causes of the errors were analyzed.The source of the error was explained.The distribution law of water and salt in the aeration zone surrounding Qin Shihuang's Mausoleum Park was clarified,revealing Mechanism of contamination of deep groundwater by excessive fertilization and artificial irrigation.The main findings are as follows:(1)The difference in pores between soils of different sites and non-remaining soils is embodied in porosity,number of pores,pore shape,connectivity and complexity of pore structure,and many pore characteristics.Fine alumina and coarse alumina all have more Soil pores and sintered soils have fewer pores;the porosity of sintered soils is significantly higher than that of the other two types of relict soils and non-reservoir soils;in contrast,there are almost no large pores with equivalent pore sizes >100 ?m in fine alumina.And the pore distribution and size are very uniform,the pore shape is also more regular,narrow and long pores and irregular pores less,uneven distribution of coarse pores in the medium,large pores,narrow and long pores and irregular pores are more,the porosity of the sintered soil The type is dominated by macropores and the morphology is more regular,and the pore connectivity and complexity are lower.(2)Fine technics can significantly reduce soil porosity,increase the homogeneity of pore structure,and make the soil structure compact.Although rough technics can improve the compactness of soil structure to a certain extent,it is generally fine with The influence of the process on the soil structure is quite different;fire will cause the soil and pores to expand,and the soil structure will become loose.The rough boring process is suitable for tamping the tomb foundation before construction,while the fine rammed soil is more stable and suitable for being used in the construction of the rammed earth wall,and plays a major bearing role in the building.(3)The spatial distribution of soil moisture in the aeration zone of the park has a strong correlation with the soil texture.The soil moisture distribution has a good positive correlation with clay particles and silt particles,but negative correlation with sand particles.The vertical distribution of water is related to the loess-paleosol sequence,and a layer of loess and a layer of paleo-soil constitute a humidity fluctuation,and the humidity increases with the depth of the profile.The distribution of salt in the unsaturated zone is greatly influenced by excessive fertilization,which causes the accumulation of large amounts of salt in the shallow unsaturated zone and threatens the salt of the buried cultural relics site;artificial irrigation of the artificial forest land leads to dry and wet changes of the soil.The salt segregation has accumulated many times in the deeper aerated zone,and it will pose a potential threat to the deeper buried groundwater as the leachate moves deeper into the aeration zone.(4)The recharge intensity of vertical infiltration of the average atmospheric precipitation over three sampling sites of artificial forest land(8#)and abandoned farmland(3#,5#)was 98.54 mm/a,133.09 mm/a,and 280.12 mm/a,respectively.The results were greatly affected by fertigation.