Introduce 300 words of characteristic caves in northern Shaanxi.

The caves in northern Shaanxi are such arched caves dug according to the mountain situation. Because loess itself has the property of standing upright, the bearing capacity of vault is better than that of flat roof, and vault is generally used in caves to ensure its stability.

Northern Shaanxi is characterized by thick soil layer and low groundwater level in the Loess Plateau, and digging caves as dwellings has the advantages of being warm in winter and cool in summer. Cave dwellings can be divided into pit type, cliff type and adobe type.

Cave dwellings dug on the ground, with caves dug on three or four sides for living, and caves in northern Shaanxi have ramps to enter and exit.

Cliff caves are caves dug layer by layer along the sides of mountains and ditches.

Adobe arch hole is built with adobe arch, covered with soil for thermal insulation. In addition, there are brick cave houses.

There are also pit caves in the western Henan plain with thick loess layer, such as the pit caves in Gongxian County, Henan Province. Often the whole village and street are built under terraced fields, and only the crown of the village and the trees on the ground can be seen from a distance. The land on the top of the pit can also grow crops. Longdong also has such underground streets. From the perspective of western environmental architects, this pit building is a perfect civilized building that does not destroy nature. The combination of underground caves still maintains the pattern of traditional quadrangles in the north, with kitchens, warehouses for storing grain, drinking wells and seepage wells, and sheds for raising livestock, forming a comfortable underground courtyard. There are ingenious treatment methods in the utilization of lots, the division of courtyards, the traffic relationship between upper and lower floors, lighting, ventilation and drainage.