What are the local factors related to the construction of Yongding Tulou?

Earth buildings are mostly square or round, mainly distributed in Yongding. There are 360 circular buildings and more than 4,000 square buildings in the county. In particular, the strange round earth building is the most traditional Hakka color and the most shocking.

A circular earth building consists of two or three circles, nested from the inside out. The outer ring is more than ten meters high, with four floors and one or two hundred rooms. The first floor is a kitchen and dining room, the second floor is a warehouse, and the third and fourth floors are bedrooms. There are thirty or fifty rooms on the second floor, which are generally guest rooms. One of them is the ancestral hall, which is a public place for hundreds of people living in the building to get married, mourn, celebrate and celebrate. There are also wells, bathrooms, mills and other facilities in the building. The earth building is rammed with local raw soil, without reinforced concrete. The width of the wall foundation is 3m, the thickness of the bottom wall is1.5m, which gradually decreases upwards, and the thickness of the top wall is not less than 0.9m.. Then it is divided into many rooms with wooden boards along the circular outer wall, and there is a corridor inside.

Earth buildings not only have the unique function of defending the enemy, but also have the characteristics of earthquake prevention, fire prevention, theft prevention, good ventilation and lighting. Because of the thick soil wall, it is warm in winter and cool in summer.

Defense requirements are the most important factor, but not the only one. In fact, many Hakka villages are square buildings and circular buildings. After careful investigation, we found that square buildings in Yongding County and Nanjing County appeared earlier than circular buildings. How to develop from a square building to a circular building is a question that needs to be further answered.

Compared with square buildings, circular buildings have seven advantages:

1, the square building's four-corner room is not popular because of the dark light, poor ventilation, close to the wooden stairs and great noise interference, while the round building excludes the corner room.

2. Compared with square buildings, there is no obvious difference in the orientation of rooms in circular buildings, which is beneficial to the distribution within the family.

3. The area of a circle with the same circumference is 1.273 times that of a square. Therefore, building a circular building can get more inner courtyard space than a building.

4. The outer arc of the fan-shaped room in circular building is longer than the earth wall, and the inner arc is shorter than the wood structure, which saves more materials than the square building.

5. The wooden components of circular buildings are of the same size.

6. Feng Shui believes that the round building can be controlled. The scientific explanation is that circular buildings have less resistance to cold air than square buildings, so the influence of evil spirits on rooms is relatively small.

7. From the seismic point of view, the circular building can transmit the horizontal seismic force more evenly, so the model house has stronger seismic performance.