History of rammed earth wall

The imperial city and palace walls of Chang 'an in Tang Dynasty were rammed earth walls, and Li Fang in the city was also separated by rammed earth walls. By the Northern Song Dynasty, rammed earth technology had made progress. The book Architectural Style, edited by Li Jie, a craftsman in the Northern Song Dynasty, systematically summarized the achievements of rammed earth slab construction technology at that time. It stipulates that "in the wall-building system, if each wall is three feet thick, it will be nine feet high and the upper part will be inclined, and the specific thickness will be halved;" If the height is increased by three feet and the thickness is increased by one foot, the reduction is the same. "Fujian Tulou has pushed the traditional rammed earth construction technology in China to the peak.