Archaeological Study Of City Walls In Song Dynasty

City walls are enclosed facilities built around the city to enhance the military defense of the city.City walls were born at least in the Neolithic Age.Through the Shang and Zhou Dynasties,the Qin and Han Dynasties,the Wei and Jin Dynasties,and the Sui and Tang Dynasties,the city wall defense capability has been continuously enhanced,the structure has been continuously improved,the ancillary facilities have been continuously increased,and the construction process has been continuously standardized.On the basis of inheriting the theory and practice of city wall construction in previous dynasties,the construction of city walls in the Song Dynasty carried out innovation and development,and established the overall shape of city walls in the Yuan,Ming and Qing dynasties.There are about 270 city walls in the Song Dynasty that have clear archaeological excavation or investigation data.According to the different administrative levels of the cities,they are divided into Central Government level city walls,Prefectures and Superior Prefectures level city walls,Districts level city walls and military temporary castles,and the archaeological data of each city wall are sorted out in detail according to the hierarchical order.Among them,there are abundant archaeological materials on city walls of Central Government level,Prefectures and Superior Prefectures level and military temporary castles,while there are relatively few archaeological materials on city walls of Districts level cities,only 8 of which are not detailed.From the perspective of plane structure,the city walls of the Song Dynasty mainly fall into four categories: single layer city walls,double layer city walls,three layer city walls and composite city walls.Different types of city walls have their own characteristics and advantages in terms of scale,characteristics,shape,terrain requirements,resource consumption,construction speed,defense capability,urban area,etc.From the perspective of three-dimensional structure,the city walls of the Song Dynasty still took rammed earth city walls as the main body.In terms of wall construction structure,it can be divided into five categories: single wall,rammed wall foundation+wall,cushion+wall,stone foundation+wall,wood pile+stone foundation+wall.In terms of wall construction materials,it can be divided into four categories: rammed earth city wall,stone built city wall,brick wrapped rammed earth city wall,stone rammed earth city wall.The types of adhesives used in the construction of city wall mainly include fine mud adhesive,lime adhesive,soil lime mixed adhesive There are four kinds of mixed adhesives of glutinous rice and lime.Through the analysis of the wall structure,building materials,the use of adhesives and the rammed earth structure of urban walls in the Song Dynasty,it can be found that the three-dimensional structure of urban walls in the Song Dynasty has the characteristics of coexistence of inheritance and development,unity and regional coexistence.The city walls of the Song Dynasty further developed on the basis of inheriting the city walls of the Sui,Tang and Five Dynasties.The wall foundation became more and more solid,the proportion of bricks and stones used was more and more large,the proportion and types of adhesives used were increasing,and the proportion of rammed earth was more scientific and reasonable.In the study of the auxiliary facilities of the city wall in the Song Dynasty,the city gates,urn cities,trenches and horse faces with rich archaeological materials were selected and analyzed in detail from the aspects of shape,structure,construction location and distribution characteristics.It is found that the ancillary facilities of cities in the Song Dynasty have further changed and developed while inheriting the previous generations.On the whole,the ancillary facilities of the city walls in the Song Dynasty were more perfect,among which the lintel type(row of fork columns)structure in the city gates of the city walls in the Song Dynasty was decreasing,and the arch type structure city gates were increasing,but the transformation from lintel type(row of fork columns)city gates to arch type city gates was not completely completed.In the Song Dynasty,Barbican structures were generally set outside the city gates,which were mainly rectangular and semicircular,and most of the Barbican gates were inclined to open.The urban trench structure in the Song Dynasty was basically stable,which was a trapezoid with a wide upper part and a narrow lower part.The width and depth were mainly affected by military factors.The distribution of horse faces on the city walls of the Song Dynasty has developed from the frontier cities of the previous generation to the widespread distribution on the city walls of various cities,mainly rectangular in shape.In addition,the city wall of the Song Dynasty was more closely coordinated with the auxiliary facilities such as the moat,the urn,the horse face,the sheep and horse wall,and the gate guard wall.Instead of fighting independently,it formed an organic defensive whole.In the Song Dynasty,the city wall and its accessories still took military defense as the main function,and played an important role in the national military strategy and urban offensive and defensive warfare.At the same time,with the development of politics,economy and culture in the Song Dynasty,the social functions of city walls became more and more.First of all,inseparable from the state administrative power,the city wall in Song Dynasty,as a carrier of political culture,is not only a symbol of political power,but also an important field of political arena.Secondly,the development of the city wall in the Song Dynasty complements the development of the citizen economy.The city wall provides conditions and venues for the development of the city economy,and the development of the city economy also provides human and financial support for the construction of the city wall.Thirdly,it was closely connected with the daily life of the people.As a material entity,the city walls of the Song Dynasty could not only divide the urban space,divide the functional areas,maintain the social order,but also provide a place for the people to play and a place for the people to transmit information.Finally,it was closely related to the city’s response to natural disasters.City walls in Song Dynasty played an important role in resisting floods,extinguishing disasters,preventing sea tides,and fighting typhoons.The difference and evolution of the plane structure,three-dimensional structure,ancillary facilities,and functional role of the urban wall in the Song Dynasty are the result of the combined effects of natural environment,urban construction history,national administration,military war,engineering technology,and economic development.In a word,the city walls of the Song Dynasty occupied an important position in the history of the development of ancient city walls in China.They inherited the development trend of the city walls of the Sui,Tang and Five Dynasties in terms of plane shape,three-dimensional structure,building materials,and functional functions.They were constantly innovated with the social progress of the Song Dynasty,and most of them were inherited by the city walls of the Ming and Qing Dynasties.