1, Yongding is located near the Tropic of Cancer, with a subtropical monsoon humid climate, with hills, mountains and river valleys as the main landforms. So Yongding is hot in summer, with southeast monsoon and abundant rain; It is cold in winter, windy in the northwest and weak in sunshine. Therefore, most of the earth buildings face south, which has the function of ventilation and cooling in summer. The north is a sealed earth wall without doors and windows, which can not only resist the cold wind in winter, but also ensure that the doors and windows in the south have sufficient sunshine. Therefore, the function of tulou is warm in winter and cool in summer.
Yongding is vulnerable to typhoon in summer with abundant rainfall. This earth building is mainly made of sand. If it is soaked in rain for a long time, it is easy to cause the earth wall to crack, the foot of the wall to collapse and the earth building to topple. Therefore, the roof of the earth building is a herringbone double slope roof, and the roof on the outside of the roof is longer and more inclined than the inside. In this way, the rain in the rainy season will be discharged to the outside of the earth building and the wall will be protected. At the same time, the root of the earth building is made of stone about 50 cm to avoid being washed away by the flood.
Yongding is located at the junction of the Pacific plate and the Eurasian plate, which is prone to earthquakes. In order to resist the earthquake, Hakka people adopted the method of bamboo reinforcement and layered tamping. The height of rammed wall is between 1.5m-2m. After each layer of soil is compacted, the sharpened bamboo will be woven and laid on the top of the wall, and the soil will be compacted again and again. At this time, bamboo strips are equivalent to steel bars. If there is an earthquake, the bamboo strips laid in the wall will be stretched to ensure the good position between the inner and outer layers of the wall and enhance the stability of the wall. After vibration, bamboo strips will shrink by themselves because of their toughness, maintaining the original shape of the wall and playing an earthquake-resistant role.
Hakkas live in troubled times. Considering the needs of life, production and defense, they created an architectural form that not only meets the needs of concentrated residential communities, but also has defensive characteristics. Combined with economy, geographical environment and efficiency, on the basis of earthen castles and earthen villages, earthen buildings with both defensive and residential functions and convenient materials are formed.