| Chinese culture has a long history.In the long years of change,Chinese earthen sites are very vulnerable to the impact of their environments.The construction techniques of earthen sites present a progressive evolution under the influence of two dimensions of time and space in their existing environments.Therefore,the study of the temporal and spatial evolution of the construction techniques of earthen sites in China is a key link to understand the relationship between earthen sites and their environments.Meanwhile,the study is conducive to the protection of cultural relics.This study mainly takes the construction techniques of earthen sites as the research object and takes the earthen sites of the national heritage conservation units as the carrier.At the same time,the study analyzes the temporal and spatial distribution of the construction techniques of earthen sites,and explores the relationship between each type of the construction techniques of earthen sites and its existing environment with the literature statistics and field investigation.In addition,multi-distance clustering function and nuclear density analysis were used to verify the temporal and spatial evolution of the construction techniques of earthen sites.Moreover,Lorentz curve and Gini coefficient are combined in time dimension to explore the mechanism of temporal evolution.Pearson correlation coefficient and the result of geo-detector are combined in space dimension to explore the mechanism of space evolution.The conclusions of the study are as following.(1)Overall,among the 494 earthen sites of the national heritage conservation units with construction information,there are 316 earthen sites with the earth-ramming technique.The number of the earth-ramming technique is the largest and accounts for 64%.The smallest quantity is the mud-stacking technique,which is only counted to 2 places.The earth-excavating technique,the technique of timber-framed mud walls and the grass-wrapped silt technique are often accompanied.(2)The temporal development of the construction techniques of earthen sites has mainly experienced several stages: germination,development,formation,fusion,and sublimation.In the early stage,the earth-excavating technique,the technique of timber-framed mud walls and the grass-wrapped silt technique were mainly used,accounting for 54.7% of the Neolithic period.With the development of the times,relatively complex technologies began to be widely used.By the Xia and Shang dynasties,the proportion of the earth-ramming technique had reached 69.7%,while the total proportion of the earth-excavating technique,the technique of timber-framed mud walls and the grass-wrapped silt technique had decreased to 10.5%.After the Yuan Dynasty,earthen sites were gradually replaced by brick and wood structures,with the proportion of earth-rock mixed structures increasing to 7.2%.Generally speaking,it conforms to the law of progress from simple to complex.(3)The construction techniques of earthen sites are aggregated distribution in various eras.The Gini coefficient at the embryonic stage is 0.512,and then the uneven degree gradually increases to 0.802 at the application stage.The inherent logic of the development of times is that the construction technologies have gradually converged into certain categories over time,and simple techniques are gradually replaced by complex techniques.(4)The construction techniques of earthen sites are mainly affected by factors such as climate,earth quality,and topography.The earth-heaping technique is mainly distributed in moist areas and humid areas with high rainfall.The adobe masonry technique is widely distributed in arid areas,accounting for 43%.Soil quality and topographical factors have less significant impact than rainfall on the spatial distribution,but they affect the operational details of construction techniques.(5)The correlation coefficient between climate conditions and the spatial distribution of construction techniques is 0.627,the quality of earth is 0.378 and the topography is 0.171.The explanatory power of the three factors for spatial distribution is climate conditions > soil factors > terrain factors,and the effect of multiple factors has a superimposed effect.Among them,the order of degree of influence of climate conditions on construction techniques is the adobe masonry technique > the earth-heaping technique > the earth-excavating technique > the earth-ramming technique > the grass-wrapped silt technique = the technique of timber-framed mud walls > earth-rock mixed structures > the mud-stacking technique.The adobe masonry technology is the most susceptible to climate conditions. |
